solubility ammoniacal ammonium salt solutions of copper, · solubility in ammoniacal ammonium salt...
TRANSCRIPT
Solubility in Ammoniacal Ammonium Salt Solutions of
Copper, Nickel, and Cobalt Components of a Waste Product
hoduced at Incois Port Colbome Cobalt Refinery
Selwyn R. FiRh
A thesis submitted in conformity with the requirements for the degree of Master of Applied Science,
Department of Chernical Engineering and Applied Chemistry University of Toronto
O Selwyn R. Firth, 200 1
National Library l*l of Canada Bibliothèque nationale du Canada
Acquisitions and Acquisitions et Bibliographie Semices services bibliographiques
395 Wellington Street 395, nie Wellington Ottawa ON K1A O N 4 Ottawa ON K1 A ON4 Canada Canada
The author has granted a non- L'auteur a accordé une Licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de
reproduction sur papier ou sur format électronique.
The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation.
ACKNOWLEDGEMENTS
The author thanks Professor Frank R. Foulkes, his supervisor, for his invaiuable assistance
encouragement and skihl guidance.
The heipfùl discussions with Professors D. Krk, and V. Papangelakis are gratefully
appreciated..
The able assistance Dr. I. Graydon for ninning thermogravimetric analysis as well as for
discussions of the experimental iesults of the work is especially appreciated.
The assistance of Ying Lee and Dan Mathers of the Analyst Lab in the Chemistry
Department for assistance with the FAA and ICP analyses is acknowledged, as is the
kindness of Phil Bearse and Dan Young of Inco's Port Colbome Facility for providing
assistance and samples of the waste stream.
The helpful discussions and encouragement fiom fellow graduate students in room 334
and room 233 are greatly appreciated.
Selwyn Robert Firth Master of Applied Science in Chemical Engineering Depanment of Chemical Engineering, U of Toronto 200 College St. Toronto, Ont. M5S 3 E5
ABSTRACT
The feasibility of using different ammoniacal salt solutions, for the dissolution of the nickel. copper, and cobalt components of an industnal waste from the INCO Pon Colborne. Ontario cobalt refinery was investigated.
The solubiIization of the cornponents was examined for various reagents on an aged sample provided, which represents the 25 year accumulation of the waste at the facility.
Several types of the waste were processed differently and then were compared to see if processing conditions affected the solubility of the different components.
It was not possible to solublize al1 of the metals from the waste however. it was shown that the processing conditions and age of the material make a difference in the solubilities of the different cornponents. The maximum solubilities of the unfiltered material were; copper. nickel and cobalt, 98, 88, 76 percent respectively.
It was demonstrated that the three metals could be electrolyticly removed from the ieachate.
TABLE OF CONTENTS
Acknowledgcments
Abstract
Tablc of Contents
List of Tables
List of Figures
i Introduction
2 Thcory and Litenturc Rcvicv
3 Esperimental
3. 1 Appamtus
3. 2 Anal!-tical Equiprncnt
3. 3 Rcagcnts
3. 4 Proccdurc
3. 5 Instmmcnt Calibration
5. 6 Analysis
4 Results and Discussion
4.1 Effcct of Leachant on rnctal solubiliiy
4. 1. a Ammonium Hydrosidc
4 I b Ammonium Sulphote
4 1 c Ammonium Cliloridc
4. 1. d Ammonium Citrate
4. 1. c Ammonium Acctatc
4. 1. f. i Ammonium Sulphate with added Ammonium Hydrosidc
4. 1. f. ii Ammonium Hydrosidc with Addcd Ammonium Sulphatc
4. 1. g. i Ammonium Chloride with added Ammonium Hydrosidc
4. 1. g. ii Ammonium Hvdroside with addcd Ammonium Chloridc
4. 1. h. i .4mmonium Citrate with addcd Ammonium Hydrosidc
4. i . i. Summary of DifTercnt Leachants
4.2 Effect of Lçaching Time
4.3 Secondan- Leaching
4.4 Effect of Hcating
4.5 Effat of Ageing
4.6 Thennogra~imetric Analyses
4.7 Plant Proccssing Conditions
4.8 Elecuo-reduction
-5.8. 1 Electro Stripping
4.8. 2 Current Eficiency
5 Conclusions
6 Recommendations
7 Rcfercnces
8 Nomenclature Used :u'PESDL\: :l
.-VPESDR B
APPEYC'DlS C
..VPENDIS D
LIST OF TABLES
Table 1 Summary of different leachants
Table 2 Cornparison of first and second leaches
Table 3 Cornparison of different treatments
Table 4 Electro- reduction of rnetals in solution
LIST OF FIGURES
Fig. 1 Extractions using Ammonium Hydroxide
Fig. 2 Extractions using Ammonium Sulphate
Fig. 3 Extractions usiny Ammonium Chloride
Fig. 4a Extractions using Ammonium Citrate
Fig. 4b Extractions using Ammonium Citrate
Fig 5 Extractions using Ammonium Acetate
Fig 6 Extractions usinç Ammonium Sulphate with Ammonium Hydroxide
Fig. 7 Extractions using Ammonium Hydroxide with Ammonium Sulphate
Fiç. 8 Extractions using Ammonium Chloride with Ammonium Hydroxide
Fig. 9 Extractions using Ammonium Hydroxide with Ammonium Chloride
Fig. I O Extractions using Ammonium Citrate with Ammonium Hydroxide
Fig. 1 1 a 24 h Copper Extractions
Fig. I I b 24 h Nickel Extractions
Fig. 1 1 c 74 h Cobalt Extractions
Fig. 1 2 Extractions with Heat
Fig. 13 Thennogram I untreated MC0 material
Fig. 14 Thennogram 2 extracted INCO material
1 INTRODUCTION
The work descnbed herein is an investigation of a potential waste reduction and resource
recovery process for an industrial waste produced by MC0 at its Pon Colbome, Ontario, cobalt
refinery .
The advent of concems over environmentai pollution in the 1970s ' ' ' led to mandatory
reductions in waste strearns. The statutes require that waste waters contain less than 5 ppm of
designated heavy metals such as copper, nickel, and cobalt.' ' ' The heavy metal hydroxide
precipitates fiom the electroplating and the mining industries were thus created as companies
complied with the regulations.
Treatment processes to lower the concentrations of designated heavy met& to levels of
less than 5 ppm must do so without dilution of the waste stream.' ' ) The insolubility of most
transition metal hydroxides at pH's of 8 - 10 "' provides a simple and cost effective method of
complying with govemment requirements for waste water discharge. The result of treating waste
water with calcium oxide ( lime ) or sodium hydroxide ( caustic soda ), produces a heavy metal
precipitate which settles out of the waste stream; this precipitate then can be collected and
dewatered to forrn a filter cake.
The preferred method of treating the large volumes of waste water at MCO's Pon
Colborne facility uses lime to adjua pH levels of the waste stream. Calcium carbonate is formed,
because of the high carbonate levels in the waste stream, which are the result of using fiesh water
from limestone formations in southem Ontario, and precipitates and mixes with the insoluble
metal hydroxides.
Ca0 + 40 --> Ca ( OH )2
Ca ( OH )2 ---- > Ca( OH )' + OR pH - 12
Ca ( OH ), + HCO', -----> CaCO, ( s ) + -0 +OH-
Me2' + 2 OH- ------ > Me(OH):(s)
The use of calcium oxide rendes the waste product unsuitable for acid leaching due to the
reactivity of the calcium carbonate formed with acids.
CaCO,(s) + 2K -----> Ca" +no +CO:(g)
Similar heavy metal hydroxide precipitated wastes are also produced by the electroplating
industry. The metal content of the different filtercakes can range From 1 to 5 percent depending
on the operator and the treatment method and precipitant chosen.
MC0 produces approximately 500 tonnes per month at 50 wt % water . of this product
in its Pon Colborne refinery. The waste sample, provided by M C 0 for this project, contains
approximately 0.6 % cobalt, 1.4% nickel and 1.7 % copper on a dry weight basis. Femc
hydroxide is 5 %, alurnina 1 S%, siiica 1% and approxirnately 85 % calcium carbonate. The pH of
the s l u q was 9.54. The actual material varies on a daily basis, depending on the upstream
processing conditions; however a given 20 kg grab sample is very uniform.
In 1994 the electroplating companies in south-western Ontario were producing another
combined 150 tonnes a month of wet filter cake containing 3- 5 % nickel on a dry basis or again
approximately haif that value wet.' ' ) These wastes may also contain quantities of chromiurn
hydroxide which cm render the wastes unsuitable for conventional smelting but which can be
processed by t his method.
INCO has been accumulating its material for the past 25 years at the Pon Colbome
facility. An estimate of the value of the rnetals contained in the waste material is approximately
li I million annually for iNCO at the Pon Colbome operation. There is also approximately $ 5 -
10 million of waste generated by the nickel / chrome electroplating seaor annually as well as a
substantiai amount of copper waste from circuit board manufacturers.
It is important to recover and recycle as much of our resources as we cm and to lirnit the
impact of disposing of the by products of out civilization as much as possible. Some nickel wastes
can be recovered by smelting if they have Iimited chromiurn content. The process herein descnbed
places no such limitation on the wastes.
It is well known that copper, nickel, and cobalt form soluble ammonium cornplexes(') and
that Shemtt Inc..' ) employs an oxidizing ammonium pressure leach process to recover copper,
nickel, and cobalt from sulphide ores. The ammonium salt and ammonium hydroxide leaching
process described in this thesis attempts to evaluate the recoverability of copper, nickel and
cobalt from the oxidized hydroxides found in the INCO waste. The process operates at room
temperature or higher and atmosphenc pressure, making it less expensive fiom a capital
standpoint than a pressurized system, ideaily leaving a markedly less hazardous product that can
be disposed of with a reduced environmental impact. The use of an ammonium-based electrolytic
process to recover waste materials of copper, nickel. and cobait is not found in the literature,
although nickel ammonium sulphate electroplating bathsc6 ' are sometimes used. Vogel describes a
quantitative analyticai technique that electrowins nickel from an ammonium solution.' ' '
Shemtt International employs a hydrogen reduction systemï a ) to recover the cobalt and
nickel fractions from its process Stream, producing substantial quantities of ammonium sulphate
( sold as fertilizer ) as a by product. The process proposed here is a method to recycle the
ammonium sait / hydroxide solution, since there is no added sulphate from the feedstock, as is the
case with Sherritt.
The work described herein is an attempt to develop and evaiuate a method of using a
combination of ammonium saits and ammonium hydroxide at atmosphenc pressure to dissolve
the vaiuable CO-precipitates of copper, cobait and nickel into an aqueous solution, followed by an
electrowinning process for their separation and recovery from the pregnant solution, thereby
allowing the leachant solution to be regenerated to effect a closed loop recovery process for
copper, nickel, and cobalt.
This work is an attempt to examine factors which affect the solubilization and recovery of
valuable minerals fiom the iNCO waste product descnbed earlier.
2 THEORY AND LITERATURE REVIEW
Priestly first produced amrnonia gas '9'in 1754 by heating lime with sa1 ammoniac
( ammonium chloride ), which had been known since about 400 BC. The sal ammoniac was
narned for the town of Ammon in Egypt where it was first produced.
It is well known that nickel, copper. and cobalt form soluble complexes with arnmonia and
ammonium salts. ' ''
The stepwise formation constants for arnrnonia metal complexes were extensively
investigated in the 1 930s by J. Bjemm, who used a glass electrode.' ' ' Me2- + MI, -----------> M~W,"
Me( NH, )," + NH, ------> Me( NH, ):'
The use of ammonia leaching was pioneered by Caron' 'O ' in the early part of the twentieth
century. Caron used an ammonium hydroxide and ammonium carbonate mixture to leach nickel
From reduced ores. In the late 1940s and early 1950s Shemtt Gordon Mines ( now Shemtt
International ) discovered that the use of ammonia under oxidizing conditions ar elevated
temperatures and pressures would oxidize and dissolve the sulphidic nickel and copper ores
without prior reduction.'"'
Sherritt then developed the process further to remove copper and iron contaminants and
to separate and reduce the nickel and cobalt fractions using hydrogen gas under pressure.' ' ' The
depleted solution of ammonia and ammonium sulphate then was stripped of the volatile ammonia
gas, which was recycled, while the ammonium sulphate was crystallized and sold as fertilker.' "'
The use of ammonium sait and ammonium hydroxide solutions. on the other hand, do not react
with the calcium carbonate or the ferric hydroxide, alumina or silica fractions. ( See Appendix B )
Thus it seemed ideai to dissolve the valuable metal components using a combination of
those reagents. The electrolytic separation of copper fiom nickel and cobalt can be achieved in
acid electrowinning systems ' l 3 ' and the same may be possible with ammoniacal solutions. ~ogel"
has described a quantitative electrolytic procedure for the determination of nickel in ammonicai
solutions, so it may be possible to produce a cobalt nickel alloy by electrowinning if the copper
first can be separated.
If electrolytic separation of copper is not possible, another technique to separate the
copper might be the use of sulphur- bearing chemicais, as implemented by Shemtt.' " ' Sherritt aiso uses an oxidative procedure that preferentially oxidizes the cobaltous ions to
cobaltic, leaving the nickelous ions which then are selectively reduced in the presence of the
cobaitic ions to separate the nickel and cobalt Fractions' "' since cobalt has the ability to form
cobaitic amine complexes whereas nickel doesn't:'"
~CO(NH,);' + N~(NH,),' + 40 + 112 O2 W ! O H ., 2Co(NH3):+ + Ni(NH,)," + ZOH.
3 EXPERIMENTAL
3. 1 Amaratus
The majority of the experiments were performed using 250 mL erlenmeyer flasks equipped
with a magnetic stir bar and sealed with parafilm. Most of the expenments were conducted at
room temperature ( 2 1 - 23 deg C ) and atmosphenc pressure for two hours. Heated experiments
were conducted using a reflux condenser, seded. but not pressure tight.
3. 2 Analvtical Eauipment
Attempts were made to use standard analytic techniques such as those found in Vogel ' ' '
for the analysis of nickel. However. this procedure was suitable oniy for certain reagents and was
abandoned. The use of UV spearoscopy also was attempted but this too was abandoned as
impractical due to the difficulty of setting up standard solutions. since dl three metal ammonia
complexes absorb light in the sarne range. Thus. depending on the ratio of metal complexes in
soiution one could get readings that were the same but the two solutions could have different
levels of ail three metal complexes.' l 3 )
Atornic Absorption Spectroscopy was found to be effective but too time consurning for
the number of samples. Induaively Coupled Plasma spectroscopy ( ICP ) finally was chosen for
the majority of the analyses. The ICP analyses were contracted to the Analyst Lab located in the
Lash Miller Chemistry building at the university of Toronto.
Thermogravimetrk analyses were performed by Dr. J. Graydon, using a Dupont
Instmments Mode1 93 1 thermogravimetric analyser located in Prof Kirk's laboratory.
3.3 Reaeents
Al1 solutions were prepared from deionized distilled water of 18 Mohm- cm resistivity.
using a MILLIPORE - Q WATER SY STEM deionizer.
Al1 reagents were ACS grade, ammonium hydroxide, ammonium sulphate, ammonium
chlonde, ammonium acetate, citric acid. sulphunc acid, nitnc acid, hydrochloric acid, potassium
hydroxide. nickel sulphate, copper sulphate, and cobalt nitrate.
Analytical standards were AA grade for AA anaiysis at 1 O00 PPM ( BDH AA Standards ).
ICP standards were Specpure@ certified NBS traceable.
Al1 solutions and residue washings were made with the 18 Mohm- cm deionized water.
3.4 Procedure
1 Extractions
A slurry was made by blending approximately 1.5 kg of the MC0 filter cake with
deionized water to a volume of 2.5 L.
Dual samples then were taken for drying at 250 C and at 105 C to establish the solids
content (approximately 30 % by weight ) and to determine which temperature gave more accurate
values for the solids content. The 105 C drying was within 0.2 percent of the 250 C drying.
Leaching experiments were set up based on the metal content of the slurry, as eaablished by ICP
andysis of either HCI or HNO, digests of a weighed sample of the sluny.
lnitially a set volume of the slurry was measured out using a calibrated graduated
cylinder. The samples then were quantitatively transferred using 1 x 10 rnL wash foiiowed by 2 x
5 rnL washes of deionized water. Later, samples of the well k e d s l u q were weighed into the
250 mL erlenrneyer flasks, a measured quantity of an ammonium salt or concentrated ammonium
hydroxide reagent added, the flask sealed with parafilm and mixing comrnenced for five hours.
Samples were taken hourly and the solutions and residues were analysed for copper, nickel, and
cobalt. It was determined From these experiments that very h i e extra material dissolved between
2 and 5 h. Thereafter the reactions were run for 2 hours.
At the end of the experiment the samples were centnfbged and then were decanted to
separate the pregnant solution from the residue. The residues then were re-suspended in fresh
deionized water. The washed residues then were centnfuged a second time. Washing was
repeated four times with wash ratios of 2 volumes of fresh water to 1 volume of retained solution.
This ensured that after washing the retained liquid per washing contained no more than 33 % of
the amount of liquid retained pnor to the wash. The clear coloured supernatant washes were
added to the pregnant solutions of the respective samples.
The respective rnixed washings and pregnant solutions then were diluted to a standard
volume using volumetnc flasks ( normally 250 mL class A ). Sarnples were retained for later
analysis. The retained samples were fbnher diluted by a known amount with 5 percent v/v nitric
acid to be in an accurately measurable range for the instrument ( For ICP and AA this was at O -
10 ppm )-
Residues of ~amples were digested using concentrated nitrk acid, and mass balances were
performed to ensure that the extracted solution contained metals in proportion to the original
unreacted product analysis.
3. 5 Instrument Calibration
3.5. 1 Atomic Absorption Spectroscopy
Fresh unopened AA standards were used to calibrate the AA spectrometer. The original
solutions were 1000 pprn guaranteed 5 5 ppm.
Calibration standards of 1, 2 and 5 pprn were made. Dilute standards of 100 rnL at 100
pprn were made by taking a 10 mL aliquot of the 1000 pprn standard and diluting to 100 mL using
class A volumetnc glassware.
A funher dilution then was made by taking a 10 rnL aliquot of the 100 pprn standard and
diluting to 200 mL for a 5 pprn standard.
An 80 rnL aliquot of 5 pprn standard then was diluted to 200 mis for a 2 ppm standard.
and a 50 mL aliquot of the 2 pprn standard then was taken and diluted to 100 rnL for the 1 pprn
standard.
The correlation coefficients of the analyses were 0.9999 using these standards.
3. 5. 2 Inductively Coupled Plasma
A 10 rnL aliquot of a rnixed 25 element, Nationai Bureau of Standards, traceable standard
was used to make 100 rnL of a 10 pprn solution of 25 elements. A ten mL aliquot of the 10 pprn
standard then was used to make 100 rnL of a 1 pprn solution. These two standards then were
used to caiibrate the instrument. The correlation coefficient for the instrument was 1.0000.
3. 5.3 Electronic balance
The electronic balance used , supplied by Van Waters and Rodgers, was a mode1
ACCULAB # VI- 3MG. The readability was 1 mg. The sensitivity was 0.003 g over the full
range of measurement of 0.000 - 3 10.000 g. A 200.000 g calibrated weight was used to verify the
accuracy of the machine before and after each use.
3.6 Analyses
Attempts to use a volumetnc method of analysis for the detemination of nickel had to be
abandoned due to interferences caused by the ieaching reagents ammonium sulp hate, ammonium
hydroxide and ammonium citrate. Attempts to use üV spectroscopy to analyse the extracted
solutions was not able to discriminate between the three different element's amine complexes well
enough to accurately determine the relative arnounts of each element, nor the total amounts of al1
elements. This was due to overlap of the absorption spectra of the ammine complexes of each of
the elements.' '"
Atomic absorption spectroscopy was anempted and found to yield excellent results, but.
due to the large number of sarnples and the lack of an autosampler it was decided to use ICP
analysis instead. ICP ( Inductively Coupled Plasma ) is sirnilar to AA in that the sample is heated
to a high temperature ( in an inductiveiy coupled argon gas Stream ) which ionizes the elements,
The ionized elements emit characteristic wavelengths of light, the intensity of which is
proportional to the amount of the element in the sample. The ernitted light is focused on a
difiaction grating which separates the beam into separate wavelengths of light. The amount of
light of each wavelength is then determined by computer analysis of a ccd ( charged coupled
device ) detector output. The levels are compared to the set of standards used to calibrate the
machine. The ICP analyser has a linearity of five orders of magnitude and can accurately measure
quantities of unknowns from ppb to pp ten thousand depending on the calibration setup. Samples
were diluted to the ppm range as a suitable method for the analyser had been previously
established for elements at that concentration.
4 RESULTS AND DISCUSSION
4. 1 Effect of Leachant on metal solubilitv
A set of timed expenments over 5 h with sarnples being taken hourly was initially
conducted. The plot of metal extracted vs time indicated that a maximum was reached at 2 h.
Therefore a 2 h reaction time was used for most of the experiments. Initiaily single reagents
ammonium hydroxide, ammonium chloride, ammonium sulphate, ammonium citrate and
ammonium acetate were used to leach the INCO filtercake. Later, combinations of ammonium
hydroxide with ammonium sulphate, ammonium chloride, and ammonium citrate were tned, to
see if there was any benefit obtained by adding ammonium hydroxide to the ammonium salt
leachants. PH rneasurements were made for the sait only experiments and the result was t hat the
pH changed very little from values of 7 to 8 for the different salts. The addition of ammonium
hydroxide raised the pH of the solutions significantly in the range between 8 at the low
concentrations to 9.5 with the addition of 50 mL of 27 % ammonium hydroxide. The effect of pH
changes the ammonium hydroxide concentration. The formation constant for the hexamine
complexes i.e. K, Ni( MI,), = 539 .
Ni" + 6 w40H < ------ > Ni( NH,)," + 6 50
6 Ni( Mi,), = 539 = [ Ni( MI,),'+] / [ Ni"] x [ Mi40H l6
The high concentrations of ammonium salts and ammonium hydroxide used ennire that the
NH,OH concentration changes very little and the activity of NH,OH will also change very little as
a very small amount of ammonium hydroxide is consumed in forming the ammine complexes. The
effiect on the hexamine complex is far overwhelmed by the ammonium ion and ammonium
hydroxide concentrations. The reactions are limited by the solubiiïty of a species rather than by
equilibnum control. The concentrations of the metal amine complexes were at levels less than
0.5 % of their maximum values in the concentrated ammonium salt and ammonium hydroxide
solutions.
4. 1. a Ammonium Hydroxide
The results of a 2 h leach using vaiying amounts of ammonium hydroxide per mole of the
desired metals copper, nickel, and cobalt are plotted in Fig. 1 below.
Fig 1 Metals Dissolved Using Ammonium Hydroxide ai Room Temperature for 2 h
O 10 20 30 u) 50 Hl 70 80 9(]
Moles of Ammonium Hydroxide per mole of metals
The results of the ammonium hydroxide leaching for 2 h at room temperature were that a
smail portion of the nickel and cobalt, 6.8 and 2.7 percent respectively, and 30.8 percent of the
copper were dissolved.
4. 1. b Ammonium Sulphate
Ammonium Sulphate is the least soluble of the ammonium salts tned, and equivalent
quantities of other salts were used as a basis for comparisons. The results of a 5 h ammonium
sulphate leach are shown in Fig. 2 below.
Fig. 2 Percent Metal Dissolved Using Various amounts of Ammonium Sulphate
O 5 10 15 20 23 30 35 40 45
Moles of Ammonium Sulphate added per mole of metal in sampk
The copper at 48.4 percent solubilization is 66 percent higher than obtained with the pure
ammonium hydroxide. There is better than a 100 percent improvement over the use of
ammonium hydroxide with the percent of nickel solubilized tnpling to 21.7 percent and that of
cobalt tripling to 9.3 percent. Note'
1 The ammonium sulphate reaction ran for 5 h as opposed to 2 h for the other extractions.
4. 1. c Ammonium Chloride
Ammonium chlonde was tned with varying arnounts to match the equivalents of the
ammonium sulphate used. The quantities used were based on the actual mole fraction of the
metals contained in the waste sample. Fig. 3 below is a plot of the results.
Fig 3 Metal Solubilized using Ammonium Chloride 2h
O 10 20 30 40 50 60 'O 90
Moia Ammonium Chtotidc Pm Mdc . M d
It is seen from Fig. 3 that there is an irnprovement in the amount of the rnetals dissolved
compared to the ammonium hydroxide leach. The copper is highest at 40 percent, followed by
nickel at 1 1.1 and cobalt at 4.2 percent dissolved. The improvements are not as great as the 5 h
ammonium sulphate leach but still substantial cornpared to the 2 h ammonium hydroxide leach.
4. 1. d Ammonium Citrate.
Ammonium citrate, unlike ammonium chioride and ammonium sulphate, is the salt of the
weak acid ( citric acid) and ammonium hydroxide which is a weak base. It dissociates in water
and its ions c m react with hydroxyl or hydronium ions; consequently it becomes a buffenng
agent. Citric acid is known to be used in the electroless plating industry.' 16' for solubizing nickel;
therefore, it was thought that using ammonium citrate might yield usehl data when compared to
ammonium chlofide and ammonium sulphate. Fig. 4a below is a plot of the ammonium citrate
extractions.
Fig 4a Metals Dissolved by Varying Amounu of Arnmouium Citrate in 2 h
A O
O 2 4 6 8 10 12 14
Moles of Ammonium Citrate added per mole of Metab
The extraction using ammonium citrate very rapidly reached a maximum afîer 6 moles per
mole of metals was added, and appeared to taper off and decrease, however, the decrease is
w i t h the range of experimental error of + 3 % and may be an anefact.
The maximum values of the extraction for ammonium citrate were 78, 70, and 62 percent
respectively for copper, nickel, and cobalt. These values were al1 higher than previous results. The
extracted value for copper was 63 percent higher using ammonium citrate than for ammonium
sulphate. However the differences for the nickel and cobalt were some 500 percent for nickel and
an astounding 930 percent increase for the cobalt extraction. Ammonium citrate also dissolved
450 mg of iron as well as the other metals. The iron levels dong with the acnial solution ppms of
nickel are plotted in Fig. 4b for cornparison purposes.
Fig. 4b Concentrations of Metals In Solution
O 2 4 6 8 10 12
Moies of Ammonium Citrate PerMole o f Metals
The maximum iron concentration is over 1800 ppm. The high iron levels led to some
difficulty in separating the solids and liquids because, as the retained solutions becarne less
concentrated in ammonium salts, some iron precipitated as colloidal ferric hydroxide. The iron
value may be unreliable due to the high levels; nevertheless, it does point out a potential problem
with the use of ammonium citrate. Ammonium acetate next was investigated to see the effect of
using a mono carboxylic acid ammonium salt as opposed to the tri-carboxylic ammonium citrate.
4. 1. e Ammonium Acetate
Ammonium acetate in solution acts as a buffering agent, as does the ammonium citrate,
since both its ions, acetate and ammonium, will react with either excess hydronium ions or
hydroxyl ions. The results fiom the 2 h reaction with ammonium acetate are ploned in Fig. 5
below.
il 00 :O 00 au0 6000 8000 100 00 120 IJO lM OO
Mokes of ammonium Acetate per moie of metals in rample
Fig. 5 Percent Metd Dissolved Using Various amounts of ammonium Acetate
I iUJ
90 -
The maximum values for extracted metals are 66, 38, and 27 percent respectively for copper ,
nickel, and cobalt. The extraction results for copper, nickel, and cobalt are midway between the
values for ammonium sulphate and ammonium citrate leaching. Iron was not dissolved by the
ammonium acetate.
80
2 70 '
i
I
- R c m t Cobolt Disolvcd Y *Percent Nickel ~ I v d
9 - /--
Next a set of experiments using the maximum concentration of ammonium sait with
varying quantities of ammonium hydroxide was carried out. Ammonium sulphate, ammonium
chloride, and ammonium citrate were used.
1. 1. f. i Ammonium Sulphate with added Ammonium Hydroxide
First a fixed quantity of ammonium sulphate was used ( 47 .9 g ) which was the maximum
amount soluble for the conditions, and corresponded to 36 moles of ammonium sulphate per mole
of metal in the sample. Fig 6 below is a graph of the percent metal dissolved vs ammonium
sulphate with added ammonium hydroxide for a 2 h reaction.
Fig. 6 Metals Dissolved Using 37.4 moles of af Ammonium Sulphate
per mole of metals with varying ratios of Ammonium Hydroxide
Pacmi C a r Di.iolved
APaœnt Nickel Dudved
Moles o f Ammonium Hydroxide added per mole of Metals in Sample
There is a quick rise to a maximum for al1 three rnetals and then the curves flatten out. The
maximum for ail three metals occurs at the sarne quantity of ammonium hydroxide added,. namely
18 moles of ammonium hydroxide per mole of metal in the sample. Next a fixed amount of
ammonium hydroxide was used with varying arnounts of ammonium sulphate added.
4. 1. f. ii Ammonium Hydroxide with Added Ammonium Sulphate
This set of expenments used a fixed quantity ( 50 mL of 15.9 M ) of ammonium hydroxide
with the addition of various amounts of ammonium sulphate. The plot of the results is shown in
Fig 7 below.
Fig 7 Metal Dissolved Using 80 Equivalents of Ammonium Hydmide and Varying amaunts
of Ammonium Sulpbate per Mole of Metab In samplc
n q 10 15 !O 3 10 $3 10
.Vola of Ammonium Sulphate Pcr M o k or Metah in Sample
Here we see a simila. trend towards a maximum extractabiiity for each metai with the copper
reaching a plateau first. Nickel and cobalt slowly climb to a maximum later with aimost identical
later stage curves. Note ' A similar cornparison next was done for the ammonium chlonde
ammonium hydroxide system.
.)
The last points on this graph were taken h m the results of the previous experiment as were the starting
values taken from the work on the ammonium hydroxide extraction.
4. 1. g. i Ammonium Chloride with added Ammonium Hydroxide
The ammonium chloride expenrnents were pattemed after the ammonium sulphate
expenments. A fixed 72 moles of ammonium chloride per mole of metal was the starting point
and varying ratios of ammonium hydroxide were added. The results are shown in Fig. 8 below.
Fig 8 Percent Metal Dissolved using 38.9 g of Ammonium Chloride
100 with varying amounts of Ammonium Hydroride
Moles of Ammonium Hydroxide added per mole of metal in samples
The results for this set of experiments parallels those of the ammonium sulphate
experiments shown earlier, with the copper quickly reaching a slowly rising plateau d e r 20
equivdents of ammonium hydroxide was added and 70 percent of the copper had been leached.
Thereafler the amount of copper leached slowly rising to a maximum of 77 percent at an addition
of 80 equivalents of ammonium hydroxide. The cobalt and nickel foliowed the trend of copper
with a slower climb to 30 percent at 32: 1 moles of ammonium hydroxide added per mole of metal
and from there a slow steady clirnb to 40 percent dissolved for both cobalt and nickel at 80 moles
of ammonium hydroxide added per mole of metais in sample.
4. 1. g. ii Ammonium Hydroxide with added Ammonium Chloride
A continuation of the ammonium hydroxide and ammonium chloride extractions was the
use of a fixed arnount ( 80 moles of ammonium hydroxide ) per mole of metal with varying
amounts of ammonium chioride added. The results of these experiments are s h o w in Fig. 9
beiow .
Fi 9 Metal Dissolved Using 80 Moles of Ammonium Hydroxide and Varying
Amounts of Ammonium Chloride Per Mole of Meta1 in Sample
The trend to a maximum continues and the curves almost duplicate those of the
ammonium sulphate with added ammonium hydroade reactions. Copper is the most soluble at a
78 percent with cobalt and nickel dissolving approximately half that amount at 40 percent each.
Next ammonium citrate with varying amounts of ammonium hydroxide was inveaigated.
4. 1.h Ammonium Citrate with added Ammonium Eydroxide
A series of experiments using 12 moles of ammonium citrate with varying amounts of
ammonium hydroxide was mn for 2 h at room temperature and pressure. The results are shown
below in Fig. 10.
Fig 10 Metal Dissolved using 12 Equivdents of Ammonium Citrate with
Varying amounts of ammonium hydroxide
Equivalents of ammonium hydroxîde per mole of total metals in sample
'O
JO
The addition of ammonium hydroxide to the ammonium citrate had no effect, as clearly
can be seen from the above graph. The respective amount for each metal extracted is the same in
.
al1 cases. The above graph demonarates the lack of effect of additionai ammonium hydroxide
1 PercentCqpsds4va l
8 P u a n t Cobait Duiolvcd -&- Perant Nickel Diuolved
when used in combination with ammonium citrate.
This can be explained by the pka of the citric acid which is a weak tri-carboxylic acid. The
ammonium citrate is completely dissociated in water. The respective ions react with water and
form the acid and base. The fiee ammonium ion can take up the excess hydroxide ion to form
ammonium hydroxide.
Note '
The overall reactions end up producing ammonium hydroxide in situ and therefore any
additional amounts would be superfluous and there would be no advantage of adding extra
ammonium hydroxide. The ammonium acetate behaves in a similar fashion.
4. 1. i Surnmary of Different Leachants
It was found that there were maximum arnounts of metd leached for each leachant. The
worst case was with ammonium hydroxide which leached very small proportions of the most
valuable materials cobalt and nickel. The overall best leachant thus far is the ammonium citrate,
which kaches up to 83 percent of the copper, 70 percent of the nickel and 60 percent of the
cobalt. The pH of the ammonium citrate solution was 7.5 at the low concentration to 8.5 at the
hi& concentration. However, the ammonium citrate also leaches high levels of iron which none of
the other leachants does. This is due to the citrate ion being tri-dentate'? thus being able to
supply three electron pairs to the femc ion and chelate it extrernely well. It is clear from the above
that the use of ammonium hydroxide with either ammonium chloride or ammonium sulphate has a
synergistic effect in that more material is leached than can be accounted for if each matenal was
3 The stepwise ionization of citrate has been ignored for brevity
acting independently of the other. The maximum percentages that were dissolved are surnmarized
in Table 1 below.
Table 1
Percent Metal solubilized with different ammonium compounds
Tercent Copper Percent Nickel Percent Cobalt
Ammonium Hydroxide
Ammonium Chioride
Ammonium Sulphate
Ammonium Acetate
Ammonium Citrate
Ammonium Chloride
plus Ammonium
Hydroxide
Ammonium Sulphate
plus Ammonium
Hyd roride - -
Temp 2 1 C, ambient pressure, 2h,
The reagents in the above table were the maximum values used in the previous
expenrnents. The arnounts of ammonium hydroxide used in those expenments with ammonium
hydroxide were al1 50 mL of 30 % solution.
4 .2 Effect of Leaching Tirne
A series of extractions were canied out over 24 h for the four most effective leachants
from the short tenn leaching runs discussed in section 4.1. They were ammonium citrate,.
ammonium acetate, ammonium suiphate with ammonium hydroxide, and ammonium chloride with
ammonium hydroxide. The experiments used four separate flasks for each experiment so that
there was no loss of matenai when sarnples were taken. The times were set for 1, 8, 16, and 24
hours. The two hour values were taken from the previous results.
The results are s h o w on three separate graphs cornparing the same metal extracted with
different leachants. Fig 1 1 a is the copper extraction, Fig. 1 1 b is the nickel extraction, and Fig. 1 1
c is the cobalt extraction. The experiments were performed at room temperature ( 2 1 C ) and
atmospheric pressure. The reagents used were as follows
Ammonium Sulphate 47. 9 g Plus 50 rnL 30 % Ammonium Hydroxide Plus 57.2 g Slurry
Ammonium Chloride 38.9 g Plus 50 mL 30 % Ammonium Hydroxide Plus 57.2 g Slurry
Ammonium Citrate 50 mL of 2 M solution Plus 57.2 g slurry
Ammonium Acetate 87 g Plus 57 g slurry Plus 25 mL water.
Fig I l a Coppcr Extracted over 24 h with Different kachanis
Fig.11 b Nickel Earacted over 24 h with Different Leachants
Fi 11 c Cobalt Ertwcted over 24 h with Dlfferent hachants
3 -0 O
i - O
. - # . P 4
Paant Cohlt Durolved Sul@tiaic - Cl Paann Coboli Durolvcd Orionde
A P a m t Cobalt Diwlved Aœwc
Perunt Cdnit Duu>lvcd C i m
O I O I! 20 3
Time h
The experiments were performed at 21 C and atmospheric pressure.
The time curves for each salt behave similarly; the absolute values differ depending on the
reagents. The results plotted above show that mon of the material is dissolved in 2 h and that only
slight additional leaching occurs from 2 to 24 h. The time curves for each salt behave similarly;
the absolute values difEer depending on the reagents. This Iack of improvement with time could
have been the result of reaching a saturated condition.
To test this hypothesis second leaching experiments then were performed on several of the
previously-leached samples using identical reagent concentrations, conditions, and times as for the
first leach.
4.3 Secondary Leaching
Four previously leached residues tiom ammonium hydroxide with either ammonium
sulphate or ammonium chloride extracts were reacted using the identical reagents and conditions.
The samples had been first leached with 50 mL of 30 % ammonium hydroxide plus 47.9 g of
ammonium sulphate or the equivalent arnounr of ammonium chlonde.
.Table 2
Cornparison of fint and second leaches
1 Am Chl Oct 24 # 8 Cu 76 4 80 78
Experiment # And
Metd Dissoived
Am Chl Oct. 24 #7 Ni
Am Chl Oct. 21 # 8 Ni ,
Am Chl Oct. 21 #7 Co
Am Ch1 Oct, 21 # 8 CO
Am Chl Oct. 21 #7 Cu
Sulp Oct. 27 # 7 Co
Although there was some secondary leaching the results were low compared to the first kaches.
Percent Metai
First Extraction
45
43
43
12
78
Percent Metai
Second Extraction
6
8
Total Percent
Metal Ertracted
51
51
Percent Extracted
in 24 Rours
47
47
47
47
78
7
9
4
50
51
82
The above table demonstrates t hat a second leach can extract fiom 6 to I 1 percent more
than the first leachV4 but it only reaches a slightly higher maximum arnount of metal than can be
dissolved in a single 24 h leach. It cm also be seen that the total values for the first and second
leaches are the same for a particular ammonium salt and ammonium hydroxide set. This would
suggest that. since not al1 the metals were dissolved in the second leach. some fraction of the
metals are in different compounds which are less soluble. That is, there are two different
compounds for each metal in the waste product. The effect of heating on the extractions using
ammonium sulphate, and ammonium chloride next was investigated to see if heating made the
materiai more soluble.
4.4 Effect of Heating
A weighed quantity of slurry was placed in a 500 m . three neck round bottomed
reaction flask equipped with a magnetic stirrer, a thermowell and a reflux condenser. The flask
was secured in a water bath which was heated using a hot plate magnetic stirrer combination. The
ammonium salt and ammonium hydroxide was added, heating started and well rnixed samples
were taken at 1, 2, and 5 hours. The solution boiled at 78 C. because of the high concentration of
ammonium hydroxide in the solution. The sarnples were well mixed throughout the experiment.
The solution volume changed with time as ammonia escaped, therefore it was decided to
separate the pregnant solution fiom the solids for each sample, wash out and collect the retained
solution and then digest the washed sample residue. Analysis of the extracted solution and the
residue digest would give a total quantity of metal for each sarnple and thus a relative percentage
f Both first and second leaches were for 2 h at room temperature and atmospheric pressure.
The 24 h values are included to demonstrate the maximum leached for the same reagents.
3 1
extracted could be calculated. The mass balances for the total metals was between 95 and 10 1 %.
The results of the 5 h heating are plotted in fig. 12 below.
Fig 12 Percent Metal Dissolved witb heliting up to 5 h
1 I 1 4 9 6
Time ( h )
The maximum amounts dissolved were reached in 1 h versus 2 without heating.
The above plot shows that the curves for copper are almoa identical at 84 percent and
that the cobalt and nickel cluster around 60 percent. Heating at 78 C did not increase the amount
of the metals solubilized to any appreciable extent. The dmost identicai curves indicate that both
the ammonium sulphate and ammonium chlonde with added ammonium hydroxide are equaily
effective leachants for this material.
4.5 Effect of Ageing
Cunosity led to dissolving some pure nickel hydroxide in the ammoniacal ammonium
sulphate. A four year old sample of purified nickel hydroxide was used. A leach of the aged nickel
hydroxide, which used 47.9 g of ammonium sulphate and 50 mL of 30 % ammonium hydroxide at
2 1 C, and which ran for 24 hours, lefi a Fraction of insoluble materiai that had the same
appearance as the original nickel hydroxide. This material was soluble in dilute ( 0.1 N )
hydrochloric, sulphunc, and nitric acids.
It was suggested , by Dr. George Babjak at MCO's Sheridan Park Research facility, that
the insoluble compound in the aged nickel hydroxide could be a basic salt of the type.
('NiOH)2S0,
Basic salts are known' '" and can be insoluble in water and basic solutions, but are soluble
in acids. However upon dissolution of the insoluble material in 10 % HCL and testing for sulphate
using a barium chioride solution there was no precipitate; therefore the insoluble matenal could
not be a basic salt, since it had been made fiom nickel sulphate. If it were a basic salt then a
precipitate of bariurn sulphate would have ensued fiom the barium chloride addition.
Nea a sample of fresh nickel hydroxide containing 5 g of nickel was added to a flask
containing 47.9 g of ammonium sulphate in 50 mL of water. The nickel hydroxide was observed
to slowly dissolve and colour the solution blue. When 50 rnL of 30 % ammonium hydroxide was
added the solution cleared before the addition was completed. The freshly made nickel hydroxide
was completely soluble in the ammonium sulphate and ammonium hydroxide mixture. This was
expected and confirms literature finding~."~ )
The jack of confirmation of a basic sait combined with the insoluble fraction in pure nickel
hydroxide led to discussions with Dr. John Graydon, of the department, regarding ways to
determine if there is an aged matenal present . It is known that ageing' " ' of transition metai
hydroxides does occur. Thennogravimetnc anaiysis was suggested as a possible way to detemine
whether there was an aged product present.
4.6 Thermogravimetric Analvses
Thermogravimetry as the narne implies is the use of heat to cause changes in the weight of
a sample. If there is a component of a systern that can be volatilized by heating the weight of the
remaining substance can be monitored. The temperature of the material will change over tirne but
there will be plateaus where energetic processes are taking place, such as the dehydration of a
hydrated salt. A sarnple of washed but othedse unreacted MC0 filtercake, and a well leached
and washed sample were analysed by Dr Graydon.
One of the problems with thermogravimetry is the small sample size; this makes it difficult
to monitor changes for relatively rninor components of a sarnple. The metal hydroxides in our
sample made up little more than 3 percent of the sarnple weight.
The graphical output is show below.
, Fig 13 Thennogram 1
Untreated INCO Matenal
Fig 14 Thennogram 2
Leached INCO filtercake
The derivative of the thennogram of the unleached material has a smail maximum which is
absent fiom the derivative of the thermogram of the leached materiai. This is an indication that
the leaching is removing ail of the materiai associated with that maximum.
Dr Graydon confirmed that a thennogram of a sarnple of the purified 4 year old nickel
hydroxide indicated that it had a sirnilar maximum. A thermogram of freshly made nickel
hydroxide aiso showed the same maximum. The occurrence of the maximums at the same
temperature indicates that a sirnilar process is taking place at that temperature. We can conclude
that the three materials contain the same substance. This may help explain the inability to dissolve
al1 the metal compounds since al1 of the material that causes the maximums is in fact solubilized.
Dr. Graydon also confirmed that a thermogram of the older purified nickel hydroxide was
found to be sub-stoichiometric for nickel hydroxide because the weight loss. at the temperature at
which hydroxide loses water to form oxide, was less than the expected arnount for the quantity of
material analysed. This helps to confirm that there are at least two different compounds in the
material.
As mentioned above, it is known that transition metal hydroxides, including nickel, age.'"'
Ni(OH),> NiO. H,O - - - > Ni0 + &O
The nickel oxide is thermodynamically more stable than the hydroxide and over time the
hydroxide will convert to oxide. This is true of al1 transition metal hydroxides and their respective
oxides.'"' The use of ammonium hydroxide and ammonium salts to separate the ammonium
hydroxide insoluble aged products from the soluble nickel hydroxide may be of some use in
investigation of the phenomena of copper, nickel, or cobalt hydroxide ageing. The possibility
that ageing had an effect on the solubility of the waste suggested that evaluating differently
treated materials might yield some information on the waste.
4.7 Plant Processine Conditions
The MC0 material is filtered using a rotary vacuum filter which draws tremendous
volumes of air through the cake. This may partially dry the cake and make the end product oniy
partially soluble in the ammonium sait solutions.
Sarnples of a 7 day old filtercake, dong with samples of influent and filter pre-feed were
obtained. The 20 L of influent was treated with 120 g of calcium oxide and the precipitate was
collected after decanting the supernatant. It then was centrifuged and transfemed to a 250 mL
erlenrneyer flask for reaction. The pre-feed was shaken to mix it thoroughly, two 100 mL samples
then were centrifuged to remove the excess solution. Samples of the 7 day old matend were aiso
taken. As well a sample of the 5 year old matenal was digested in 5 M sulphuric acid and then
reprecipitated using lime.
Each of the samples then was reacted with 47.8 g of ammonium sulphate and 50 mL of
concentrated ammonium hydroxide for 2 h at 22 C. The samples then were centrifuged and the
residues washed and the washings collected. The respective pregnant solutions and washings were
CO-mingled and diluted to 250.0 rnL for anaiysis.
The washed residues of the above materials were al1 digested in concentrated Ntnc acid,
the digests were centrifuged and the clear solution decanted. The residues from the digests then
were washed and the solutions added to the clear digest and diluted to 250.0 mi,.
Table 3 below is a cornparison of the results of processing conditions on the leachability of
the metals.
Table 3
Extractions of different precipitates of 16 g solids
47.9 g ammonium sulphate with 50 mL of 27 % ammonium hydroxide
II Type of Rcsidue 1 % Copper Dissalveci / % Nickel Dissolved 1 % Cobalt Dissolved
7 Day Old Cake 1 94 I 81 I 55
Old Cake
Note '
Copper is little affeaed by the age of the materiai whereas cobalt is the most affected.
Ufiltered prefeed and re-precipitated material behave simiiarly for al1 three metals. The seven day
old cake was dmost as good as the ufiltered pre-feed materiai for copper and nickel extraction
but was only slightly better for cobalt than the five year old material. The laboratory preparation
of material using lime as a precipitant was not as good as for the re-precipitated material even
though both products were made using the same reagents and following the same protocol.
From the results obtained there is clear evidence that the metals are precipitated as their
hydroxides and that by the time they exit the rotary vacuum filter they have aged sufficiently to
render a portion of each insoluble in the ammonium hydroxide ammonium salt solutions at
atmospheric pressure and with limited ammonium hydroxide present.
1 l
- - - - - - - -
82 50
5 The experimental volumes were 130 mL each
39
48.1
The MC0 material is first precipitated in very large 1,000,000 L reactors and as a resuit it
will have aged for several weeks before it is filtered. This may explain why 12 percent of the
nickel and 24 percent of the cobalt is not removed fiom the pre-feed material.
The lower levels of cobalt leaching as compared to the nickel, rnay be explained by the
observation that wet cobaltous hydroxide formed a dark higher oxidation product when it was
shaken in air as happened with a sample of fieshly made pink cobaltous hydroxide that was being
washed in the \ab.
The ageing process may change the hydroxide Me ( OH ), to a metal oxide hydrate with a
formula MeO. H.O. This is an interesting question and the use of an ammoniacal ammonium salt
solution may be a way to separate that component of an aged system, at least for copper, cobalt
and nickel hydroxides.
The inability of the ammonium hydroxide / ammonium sulphate mixture, which clearly
dissolves nickel hydroxide, to completely dissolve the nickel fraction fiom the waste matenal
leads one to conciude that there are at lest two distinct nickel containing chernical compounds
present. The aged nickel hydroxide may explain why there is an insoluble fraction but it does not
prove that the insoluble compounds in the waste are a result of ageing of the hydroxide
precipitates.
M e r the leaching investigation a prelirninary investigation of the practicality of using an
electro-reduction to recover the metais from the ammonium sulphate solution was investigated.
4.8 Electro-reduction
4.8. 1 Electro Stripping
This experiment was to demonstrate the practical ability to remove the copper, nickel, and
cobalt frorn solution and to thus be able to recycle the barren Ieaching solution so formed. Table 4
beiow is a tirne vs % removal of the three metals.
Table 4
Electro-reduction of metals in ammoniacal ammonium sulphate solution.
V = 4.0 volts 1 = 0.5 amperes Measured at the electrodes
L
The above table resulted from an electroplating experiment by which ferrous ions were
dissolved from a steel anode and the copper, nickel, and cobalt ions were reduced and deposited
onto a stainless steel cathode. The dissolving ferrous ions were being oxidized by stimng the
solution in air. The air oxidation was continued for an additional ten hours. The ievel of iron in the
solution after precipitation of femc hydroxide was Iess than 1 ppm.
This preliminary experiment was done merely to dernonarate that the three met& could
be effectively stripped from an ammoniacal ammonium sulphate solution using an electroplating
technique and that the ferrous ammonium sulphate in solution, could be air oxidized to remove
Time h
O
24
40
Percent Copper
removed
O
98.5
99.9
Percent cobalt
removed
O
78
98
72
Percent nickel
removed
O
12
34
99 99.9 99
the iron as ferric hydroxide, which is insoluble in ammoniacal solutions' I9 ', leaving a regenerated
barren solution for recycling.
The effective process is that steel reacts with the copper, nickel, and cobalt hydroxides
plus oxygen to fom femc hydroxide and the metals. This will use less energy as it is easier to
oxidize iron than to oxidize water by almost a full volt.
The results from air oxidation of the ferrous sulphate in ammonium hydroxide were that
the intense blue colour had completely disappeared, indicating that the ferrous matenal had been
oxidized to ferric and that femc hydroxide had been precipitated. There was a noticeable build-up
of ferric hydroxide in the bottom of the beaker.
1.8. 2 Current Efficiency
The initial concentrations ( ppm ) of metais in solution were Ni 10,294 Cu 144 1
and Co 2065. Solution volume 500 mL volumetric class A.
The molar quantities are 0.17755 mol Ni, 0.02268 mol Cu and 0.03 504 mol Co.
The current was 0.5 A for 72 H. Therefore 72 X 3600 X 0.5 C = 129600 Coulombs.
96,487~ Moles of bivalent metal are 0.2353 and requires 0.2353 mol x (5) x (F-) = 45 40 1 C . 45,JO l c Therefore the current efficiency (-) x 100 = 3 5 Percent.
This investigation was preliminary and was an attempt to demonstrated the practicality of
electro-reduction to remove the metals. The development of an electrolytic recovery is
recommended.
5 CONCLUSIONS
1. The use of an ammoniacal ammonium sulphate or ammonium chloride solution to
extract the copper, nickel, and cobalt fiom freshly made or non vacuum filtered M C 0 waste has
some merit and may have some application in industry.
2. The waste as produced yielded lower solubility than waste that had not been vacuum
filtered. Also, the older waste had a markedly reduced solubility of the nickel and cobait fractions.
3. Ammonium citrate, while an excellent leachant, aiso dissolved the undesirable iron
component and was aiso heat sensitive; therefore it is not recomrnended as a leachant for this
product .
4. Heating the solution at atmosphenc pressures had no advantage in solubilizing the metal
components.
5. A two hour leach effectively dissolved most if not al1 of the soluble components of the
waste.
6. The use of an electroplating process utilizing iron to replace the copper, nickel and
cobalt in solution would ailow for the leaching solution to be recycled, since the iron then could
be precipitated and removed with the leached residual waste.
6 RECOMMENDATIONS
1. Further work should be performed on developing an effective electrolytic recovery
system for the ammoniacal ammonium sulphate solution. The nature of the ammoniacal cornplex
changes the nature of the system with reference to electrode reduction voltage characteristics of
the metal.' "
2. The use of membranes to keep the anolyte and catholyte separated to reduce the
possibility that iron could CO-deposit with the other metals should be investigated.
3. A high temperature and high pressure ammonium hydroxide and ammonium sulphate
leach for the aged material rnay lead to a viable process for the recovery of the wastes that have
been stockpiled.
4. Investigation of the nature of the insoluble aged nickel with ammoniacal ammonium
sulphate may help understand the ageing of transition metal hydroxides better.
7 REFERENCES
Environmenta1 Protection Act Ont., Section 309
Atlas of Electrochemical Equilibria in Aqueous Solutions. M. Pourbaix NACE
Data Collected FFom survey that the author compiled in 1994
Meta1 h m i n e Formation In Aqueous Solution, J. Bjemm P. Haase And Son 194 1
Ammonia Pressure leach process for recovenng Nickel, Copper, and Cobalt from Shemtt
Gordon Nickel Sulphide Concentrate, F. A. Forward. Transactions Volume LVI 1952 pp
373 - 380
Mellor's Modem Inorganic Chemistry 1939, G. D. Parkes and J. W. Mellor
A. I. Vogel " A Textbook of Quantitative Inorganic Anaiysis " 3rd ed. Longmans.
Reduction of Nickel by Hydrogen from Ammoniacal Nickel Sulphate solutions. V N.
Mackiw. W. C. Lin, and W. Kunda. p 786 Journal of Metals 1957.
Ammonia, A. V. Slack 1973 Marcel Dekker Inc.
Ammonia Leaching of Nickel and Cobalt Ores, M. H. Caron Transactions AIME Vol.
188 1950 Journal of Metals 67
Chemistry of the Ammonia Pressure Process for Leaching Ni, Cu, and Co from Shemtt
Gordon Sulphide Concentrates. F.A. Forward and V. N. Mackiw Journal of Metals
Mach 1955 pp 457 - 463
Operation of a byproduct ammonium sulphate plant at Shemtt Gordon Mines Limited.
J. Stiksrna, R. Schech and M. McKimon Presented at the International Symposium on
Crystallization and Precipitation, Saskatoon, Saskatchewan, Oct 5 - 7 1987.
Metallurgical Improvernents in the Treatment of Copper - Nickel Ores. The Staff of
MC0 MME Journal of Metals vol. LI 1948 pp 187 198.
The Recovery o f Cobalt by The Soluble Cobaltic Arnmine Process, R. Stauffer and S.
Lindsay Presented at the Conference of Metallurgists of the Canadian Institute of Mining
and Metallurgy in Toronto, Ontario, August 29 - 3 1 , 1966.
Stability Constants of Metal Ion Complexes 1964, J. Bjemm The Chernical Society
London
Handbook of Electroplating 1999, American Electroplaters and Surface Finishers.
Basic lnorganic Chemistry 1976. F. A. Cotton and G. Wilkinson. John Wiley And Sons
Mellor's Modern Inorganic Chemistry 1939. G. D. Parkes and .J W. iMellor
Inorganic Chemistry 1894. G. S. Newth. lonmans Green And Co
Inorganic Chemistry 1967, R. T Sanderson, Reinhold Publishing Corporation
8 NOMENCLATURE USED
The following nomenclature was used
Sample weight
Sample Volume
Solids content
Solids in a volume
Analyte
Dilution Factor
Diluted Volume
Residue
place
Residue Digest
Total metals moles
means the weight of a sample used in a reaction
means the measured volume of a sample of slurry of known solids
content
means the fraction of solids in a given sample
means the theoretical dry weight of a sample based on dried
standards
means the analysed sample d e r dilution
means the amount the original sample had to be diluted by for an
accurate anaiysis to be performed
means the standard volume to which the extracts and digests were
diluted to (in most cases this was 250 rnL )
means the undissolved solids remaining afker a reaction had taken
means the solution obtained by reacting a residue with excess acid
means the sum of the theoreticai moles of the individual metals in a
sample based on ICP analyses of nitnc acid digests of dud
samples
Percent metai dissolved means the arnount of metal dissolved compared to the
theoretical amount in a given sample
APPENDIX A
Sample Calculations
- 1 - To calculate the weight of a metal dissolved where the residue was not digested
Weight dissolved = analyte concentration ( pprn ) X dilution factor X standard volume of
solution ICP (analyte ppm 9.43) X IO0 X 0.25 L = 235.75 mg
Weight in HNO, digest = ICP Value for HNO, Digest X dilution factor X Standard
Volume of solution = 9..78 ppm X 100 X 0.25L = 244.5 mg in digested sample of sluny
Metal Fraction per dry weight of solids
= weight of metal in digested sarnple / ( Sarnple wt of Slurry X fraction of solids )
= 244. 5 mg 1 ( 57285 mg X 0.29 13 = 0.0 146 metal fraction in dried slurry
Percent dissolved = weight of metai dissolved / weight in sample X 100
For a sample weight of 64.569 g with a solids content of 29.13 % and a metal fraction of solids
of 0.0 146 The ICP value might be 8.714 for a 100 : 1 dilution of a 0.250 L standard volume.
Weight dissolved = 8.7 14 ppm X 100 X 0.250 L = 2 17.85 mg dissolved
Weight in sample = weight of sarnple X solids fraction X rnetal Fraction in dried slurry.
Weight in sample = 64.569 X 0.2913 X 0.0146 = 0.2746 g
Percent dissolved = weight dissolved X 100 / weight in sarnple
= 2 1 7.85 mg X 100 / 274.6 mg = 79.33 Percent of the metal dissolved
-2- Where there was a residue digested the total weight of the metal is known
Weight in extract = analyte concentration ( ppm ) X dilution factor X standard volume of
solution
9.. 78 ppm X 100 X 0.2SL = 244.5 mg in digested sample of slurry
Weight in residue = ICP Value for HNO, Digest X dilution factor X Standard Volume of
solution
Total weight = Weight in extract + weight in residue digest
Percent Dissolved = Weight in extract 1 total weight X 100.
weight in extract =1 ICP Value 9.43 X 100 X 0.25 L = 235.75 mg
Weight in Residue Digest = ICP Value 2.43 X 100 X 0.25 L = 60.75 mg
Total weight = 23 5.75 mg + 60.75 mg = 296.50 mg
Percent Dissolved = 23 5.75 X IO0 / 296.5 = 79.5 1 .
APPENDIX B
TABLE OF 22 ELEMENT ICP ANALYSIS
A 22 element analysis of ammonium sulphate with ammonium hydroxide Expt 8 July 5 , 2000
Sample-lD Analyte 758 Ag 328.06 758 A1 308.21 5 758 As 188.97 758 Ba 233.52 758 Be313.10
Mean-ST -0.138 1 01 -0.050527 0.362958
-0.018548 -0.004961
RSD . Cal-Units Std-U 1 Std-U 2 1.151 mg/L -0.13781 1 -0.136675 3.337 mg/L -0.048582 -0.05 1 586 1.80I. mg/L 0.355643 0.368233 0.897 mjjL -0.01 8584 -0.01 8366 0.339 lm& -0.004975 -0.004942
Std-U 3 -0.139816 -0.05 14 12 0.364997
-0.0 18693 -0.004965
APPENDIX C
Raw ICP Values for the rnetals Copper Nickel and Cobalt
July 5 2000 Ammonium Sulphate with Ammonium Hydroxide
[Sample-I 1 Analyte Mean-ST RSD Cal-Units Std-U 1 Std-U 2 Std-U 3
119l61'f .E :69188f'E :Z ; ILE68f-E ; 1 ,EO-3tl'S SESISI'O .LIL16E'f !N 00'Za !?;'~LzL 5ESL09'C f SI CG97 ii: 16S6P19-f 1 1 EO-306'L 15 16101'0 (69ZS19'5 !N OO'SG !S;UZL 9628t.8'1 : f . L6LECS'I ;5 !86nE8'1 1 i €0'308'8 ; L Ob8ft'O ' t 9 18C8' 1 !N OO'ZCL !N'9LSf SSIûl6'0 f tlC696.0 :Z :ZIPL6'0 1 i EO-39S'Z SELC9Z'O ,LOSIL6'0 !E; OO'ZEi !NISLSL SbSl9f'O . E E86LSf.0 ;5 !91t19E'O 11 r EW38T'f I8LC806'0 . S 1 f 19f.0 !S OO'ZEZ !K itLSL 20'38L'L ' E ZO-3EI'L Ii: ;Z0-386'9 : 1 i EO-38t' l 8599LO-Z ;O-3E I 'L !K OO'SEZ !.h; i ELSL 20-38t.Y f ITO-30'2 IS iSO-3Sl.i: 1 1 'CO-3ZCC !8019t'01 mZO*XZT !N 00'Slc !SISLZL ZO-390'1 f CO'XS'6 ; Z 120-3CW1 : 1 : t i)-3tI 'S i S8P690.5 : 20-310'1 !N OO'SCi !.";' l LZL
ZIlS66'0 E 106686'0 ;Z ' 81 ES86'0 1 ; CO-306't i 6S6Mt'O 1 1066'0 03 19'8Zi: 03 8LSL 68MlL'O S E 161f9ZL'O If IZIZSZL'O 1 1 ! CO-318'C ! 186925'0 L08EZL.O 03 I9'8ZC 03 UZi ZEtSSt'O : C :t9IlSt'O ;Z ! 898ûSt.0 ! I 'fW3SS'Z I 18t49S'O .88tZSt'O 03 1 9'8X 03' 9LZL SOSZ 12'0 ' C I8ZLllZ'O iZ ItZllZ*O ' 1 .t@310'8 4108UE0 ~Sf6115'0 03 19.822 03 SLLL 20-3St.9 f sZ0-3X~9 ;Z 150-3L C'9 : 1 , EO-391' 1 ! 9ZOtE8' 1 ; 20'3PE.9 03 19'855 03 tLZL Z05?Sl'l E '20-3LZ I : Z 120-XI'1 11 i ti)-Xt.'9 1 L90SOt-'5 ' ZO-30;' 1 03 1 9'822 03 EL TL EO-Xt 'Z ' E I fV396‘1 :Z I CO-305'1 ! 1 I W3SO't I WLS'bZ €0-3L6' I 03 8 19'8SZ 03: SLSL EO-3S.Z- IWd30'f 1 CO-3t.Z- 100-30'5 I EO-31'2- I 1 I W-39L-1 I I SEWS'L i CO-3E.Z- 03 19'8ZZ 03 ILZL ,3) 3 ~ 3 ~ 1 r ; I W % ~ ? I O ) 3 ~ m ~ IWI(~!PD) ~ ~ ~ S I O N ~ h i ( q ! m ) as ~03) am ;m) 3 ~ 0 3 ~ 1 3 N a r i l w v ~ a l aldute
Ammonium Chloride with added ammonium hydroxide
Sample-1 Analyte Mean-ST RSD Cal-Units Std-U 1 Std-U 2 Std-U 3
Ammonium citrate with added ammonium hydroxide
Sample-1 Anaiyte Mean-ST RSD Cal-Units Std-U 1 Std-U 2 Std-U 3 720 1 Cu 324.75 9.142995 0.154 rndL 9.126801 9.149312 9.152873
APPENDIX D The raw ICP Values and the Respective Spreadsheets of Experiments The Tables in this section are used to calculate the percent of metal dissolved or removed February l e - 14 e
Ammonium Sulphate Extractions
kmplc Dilutcd Pcrant ldcnufiatio Slmplc Fnaion Gnatnuati Diluum SImplc H g GbJt C d d t n Eicmcnt Mcan-ST SD-Calib RSD Cal-Uni& Weighr g Mcul ai F a a a Vdume ûissdvcd D iudved march7-le Co 278.6 16 0.03251268 0.002031 6.167 m u t
Samptc-ID Analyre Mean-ST SD-Cdib RSD Cal-Unics march7-lc Ni 31003 0.11 11579 0.00343 3.M mg& march7-2c Ni 3 2 0 0 3 0,338261 0.005213 1.541 mgiL march7-3c Ni 31003 0.W18M58 0.006116 0.768 mgfL march7-k Ni 232003 1.3079563 0.006103 0.522 mg/L march7-5t Ni 233303 I W Q S I O.W327 O. 121 mg/L march7-k Ni 232003 2.7295044 0.015495 0.567 mg/L march7-7e Ni 23303 12.091665 0.074397 0.615 mg/L rnarch7-tk Ni 232003 18.969963 l). 115797 0.61 mglL
Sample Pcrant Dilution Volumc Mg Nidctl Nickel
Sid-U 1 Factor ( L ) Dissolved üissolvcd 0.0132 O. 114942 10 0.25 0.287355 0.130616 0.0132 0.342971 10 0.25 0.857427 0.38974 0.0132 0 .WW3 10 0.3 102JS07 0.9203 O.0132 1.306948 10 0.25 3.37371 1.485169 0.0132 1087527 10 0 . 3 5.218819 2.37219 0.0132 L%?28f 10 0.25 6.WMJ55 3.ü93M3 0.0132 12.Olm 10 0.15 30.04313 13.65597 0.0132 18.dSW7 10 0 . 3 47.t46û5 21.43002
March 19 Ammonium Chloride extractions
Experimen t Mar 19- 1 Mar 19 - 2 Mar 19- 3 Mar 19 - 1 Mar 19 - 5 mar 19 - 6 Mar 19 - 7 Mar 19 - 8
Dilution 10 50 50 50 50 50
100 100
Experirnent Analyte AauaI Mg of Perant Idzntificatio Dilution Sampie Copper Conanira Standard q p e r Cappcr in n Faaor wcighr Conc tion ppm volume dissolved Solution
PPm Cu Aaual Volume Mg's in 16.652 1.9 1 19.1 0.25 4.775 16.652 0.874 43.7 0.25 10.93 16.652 1.351 67.55 0.25 16.8875 16.652 1.638 81.9 0.25 $6.475 16.652 2.225 11 1 . 3 0.25 27.8125 16.652 1534 126.7 O . 31.675 16.652 3.42 342 0.25 85 5 16.652 4.481 448.1 0.25 112.0?5
Dilution Faaor for Co and Ni
Dilution Mar 19- 1 1 Mar 19 -2 1 O Mar 19- 3 10 Mar19-4 10 Mar 19 -5 1 O rnar 19 - 6 10 Mar 19 - 7 10 Mar 19 - 8 10
Dilution Mar 19 - 1 1 Mar 19- 2 10 Mar 19- 3 1 O Mar 19 - 4 1 O Mar 19 - 5 10 mat 19 -6 10 Mar 19- 7 1 O Mar 19 - 8 10
Analyie lobalt Auual Pcrtxnt Concentra Concentra Standard Mg Cobalt Cobalt lion [ion ppm VoIum dissolved Dissolvtd
Conc in Mg's Co PPM Co Sol'n Volume in Sol'n Perœnt
16.652 0.661 0.661 0.25 0.16525 0.2 16.652 0.047 0.47 0.25 O. 1175 O. 1 16.652 O. 102 1.02 0 . 3 0.255 0.3 16.652 0.143 1.43 0.25 0.3575 0.4 16.652 0.17 1.7 0.25 0.325 0.5 16.652 0.173 1.73 0.25 0.4325 0.5 16.652 0.904 9.84 0.75 2.46 2.7 16.652 1.812 18.12 0.25 4.53 4.9
Conc in Standard Perant in PPM Ni Sample Volum mg In soln Solution
16.652 1.9 1.9 0.25 0.95 0.4 16.652 0.308 3.08 0.3 1.54 O. 7 16.652 0.782 7.82 0.25 3.91 1 .8 16.652 0.9U 9.44 0.25 4.72 I I 16.652 0.778 7.78 0.25 3.89 1.8 16.652 0.961 9.6 1 0.25 4.805 -.. 9 9
16.652 3.219 32.19 0.25 16.095 7.3 16.652 5.214 52-14 0.25 26.07 11.85
Ammonium Citrate
Mg's in Soi'n
115.65 160.1
l69.n 193.8
197.55 IIrS17
-Tm33
Percen t Copper in Solution T'mu72
3 1.m 61.O6tTS
10.43 165 -7-mm3 -773m35
16.- 73;2554
Pcrccni Nickel in Solution 3.2 J4.5
J . - -IaO Y
39.3
7 36.6
'Moles Ammoniu m Citrate per Mole Metal
Copper in Solution
Perm t Cobalt in Solution D
7.0
3 4.3 43. r 94.0 60.7 66.4 69.5
Ammonium Sulphate With Ammonium Hydroxide
I 1 I
t Ihmiol m d -a l lUW#ls l l rq# lbmraml w h d
- b d d l -MC- I U o f C - dC-i- C d C U W u m e i m l & I 1 u?rip* 4 8 ) -- =iip*
O a137 O r OCMM flmlb 1 6 0 ~ -
O ml7 «,3llI / 0- O IR16 umir / o r n a - 0 m37 O (Rlb
1
O.O(U7 O,?l 1 U t m m O WI8 - omis 1 U a m '
n m n 0-WI I o a w omm o m i s 1 a m m 7 o w O 1 o m m 0 . m ~ ornia i aum.
Ammonium Chloride With Ammonium Hydroxide
Ammonium Acetate
Ammonium Citrate with Ammonium Hydroxide
Fnaian of Nickcl in Soli&
= 0.013: (1.013; m 1).013; 0.0f3;
nicorctia I Mda of Cobalt in Sample
7nmlm -Umm5 -omlm U.ODTS57 7Imm [IIWISn [lI1101568 O.W156
nicorciia 1 mola ot mdal in vmplc
-lJlmm -immla -lmmm -inmm O.W9685 -unFm -Umm m
Paœnt Cobal i
Dirtolvcd
63I3! T T -59.g? aI.Y = -7im
tual yc Conan tri iim ppn
Nickel ïE33m 6.16267,ç -inRZR 6.[]97CiS1 ï5lmm 7cmmT XxFm b.71KJS5;
aalpc Con a n in
tim ppm Cappcr
TRw -xm%3 -mmm ggn(JS7 V.102611 V.Z67PJ7 T+mm Tmm
24 Hour Experiments Ammonium Acetate
Smplc Thmct ia Identification Elcmenr Analyic Weighi l T o u l Thcœclia t\mmcmium & Ehmcni Concentra Anaiyic Nickel Soli& Ppm of weighr of I mole Percent Aatatc Mdytc wvelengr a d d tim ppm Dilution Vdume Durolved Waghi of Conicnt d mctal in mcul in ofmeul in Mcrai Extractions Numkr h for Meul Fa- ( L ) ( mg ) Emplc Emple Solids wmple m p l e Dirpolved I h am a m 16 Ni 31003Ni 3.7W836 100 0.15 976É091
Ammonium Citrate
24 h Ammonium Sulphate with ammonium hydroxide
Sarnple Identification Am moni um Sulphate with Ammonium Hydroxide Extractions 1 h am sulp 8h am sulp 16 h am sulp 25 h am sulp
Elernent Sr Element
Analyte wavelengt Analyseci Number h for
6 Ni 232.003 Ni 7 Ni 232.003 Ni 8 Ni 232,003Ni 9 Ni 232003 Ni
Anafyte Analyte Analyte Weigh t Concentra Concentrati Concentra Analyte Nickel tion pprn on ppm tion ppm Dilution Volume Dimlved Nickel Coppet Cobalt Faaor ( L ) ( m g ) 3.233%1 8.12668652 1.4035 1 100 0.25 80.84904 3.985885 9.09057034 1.715985 100 0.25 99.64713 4.247242 9.35844669 1.807734 100 0.25 106.1816 4.319696 9.41 160789 1.83755 100 0.25 107.9923
Theoretici Theoretica l Total Theoretica I Total
Weight of Solids Ppm of Ppm of PPM of weight of 1 moles of weight of Weight of Copper Cobalt Weight of Content of Nickel in Copper in Cobalt in nickel in nickel in Copper in dissolvcd Dissolved Sample Sample Sol ids sol ids Solids sample sample Sample
203.167163 35.234 57.962 0.29135 0.0132 0.0167 0.0055 0.2291 1 0.003802 0.282017 227.26125&1 42.900 57342 0.29135 0.0132 0.0167 0.0055 0.220527 0.003761 0.279 33.961 1 6 2 45.181 57391 0.29135 0.0132 0.0167 0.0055 0.220715 0.003765 0.379238 235.2901972 46.189 57.273 0.29 13s 0.0132 0.0167 0.0055 0.2û262 0.003757 0.278664
Theoretica 1 Total Theoretica weight of I Moles of Peraent Percent Percent
T7ieoteticaI Moles of Cobalt in Cobalt in Copper Cobalt Nickel Copper in Sample sarnple Sarnple dissolved Dissolved Dissolved
0.004438412 0.09288 0.001576 72.04 37.93 36.27 0.004390936 0.091 886 0.001559 82.46 16.69 45.19 0.004394688 0.091965 0.00156 1 83.79 49.13 $8.1 1 0.003385652 0.091 7ï6 0.001 557 84.43 5033 49.03
24 h Ammonium Chlonde with ammonium hydroxide
Smplc Idenlincation Ammonium Chloride with Ammonium Hydraxidc Exinctions 1 h am ch1 8h am ch1 16 h am ch1 24 h am ch1
A d p e Anaiyte Amiyte Weight Element Gncmuati Conccntrati Conantrati M y t c Nickel
N y t c Elemcnt & Analyscd on ppm on ppm on ppm Dilutiar Volume ( Dissalved ( Nurnber wavclcngth for Nickel Copper Cobalt Faam L ) mg )
1 Ni 32.003 Ni 3. 127884 7.836025 1.31 1523 100 0.25 78.19709 2 Ni 32.003 Ni 3.861 229 8.464101 1.6 19582 100 0.25 96.53074 3 Ni 332.003 Ni 3.876488 8.346 f 24 1.630079 100 0.25 96.9122 4 Ni 02.003 Ni 4.128037 8.685067 1.73 1632 100 0.25 103.2009
Theoretid Theoretical Total nieoreticai Total
Weight of Solids Ppmof Ppm of PPM of wcight of molcs of wcight of Weight of Coppcr Cobalt Weight of Content of Niclel in Coppcr in Cobalt in nickel in nickel in Coppet in drssolved Dissolved Sample SampIe Solids solids Solids samplc samplc Sample
195.9006262 32.788 57.03 1 0.291 35 0.0132 0.0167 0.0055 O.?lW3 1 0.003741 0,27487 21 1.603 132 40.490 58.676 0.29135 0.0132 0.0167 0.0055 0.225465 0.003846 0.285247 208.6531021 40.752 59.389 0.29135 0.0132 0.0167 0.0055 0.22399 0.003896 0.28896
217.12668 43.291 57.239 0.29135 0.0132 0.0167 0.0055 0.2201 3 1 0.003755 0.278499
Theorciical Toial Theuetical weight of Molcs of Perant Percent Ptrant
Thcoteticil Moles of Cobalt in Cobolt in Coppcr M a l t Nickel Coppcr in Sample sarnple Samptc -olvcd Dissolved DiJsolvcd
0.0043671 21 0.091388 O.Ool55 1 70.60 35.88 35.65 0.00J589258 0.093943 0.001594 74.18 13.10 42.81 0.004537684 0.095 166 0.001 6 15 72.21 42.82 42.43 0.004383049 0.09 1721 0.001 556 77.96 47.20 46.88
Heated Experirnents Ammonium Sulphate
u m5 urnb
um:
Heated Ammonium Chloride
Concctcd values Of
Mgs Nickel in solution 62.1 61.1 m -11.0 7 T
16.2 37.8 --3m3
Nickei
Sample dissolved 60.0 0.a
110.0 0.6f 300.0
Different Treatments
FreshCake and Lab Preps Sarnples
Solut ion Total Percent Analyte Element & Sarnple Fpm In Dilution Pprn in volume Mg Cobalt cobalt Numkr Wavelcngth Wemcnt Identification analytc factor solution ( 1 ) ûissolved ( mg ) d i d v c d
25 Co 28.616 Co ûec 27 1000 1nm 10.03365 4 40.17361 0 . 3 10.04 33.66214 57.5539049 29 C o 3 6 1 6 Co Dec 27 lnco exua 0.544739 100 54.47393 0.25 13.61 30 Co 28.616 Co Dec 27 Inca extra 0.61241 100 61.24103 0.3 153 1 26 Co 28.616 Co Dec 27 $000 Inn, 11.95955 4 51.83819 0.25 12.96 28.2698 54.15763 12 31 Co 28.616 Co ûec 27 Lab 2000 1.879618 100 187.9618 0 .3 46.99 27 Co 228.616 Co k c 2'7 2000 Lab 44.01632 4 176.0653 0 . 3 44.01 91.00678 51.633021 1 32 Co 228.616 Co Dec 2'7 300 Lab 1.59381 100 159.381 0.25 39.85 28 Co 228.616 Co Dec 27 2000 Lab 35.1 1644 4 140-4657 0.25 35.11 74.9617 53.1541613
Percent Cob Percent Copp Rrccnt Nickel Dissolved Dec 27 lnco c5755390402 93.68962702 8234763859 Dec 2'7 fnco e54.15763125 93.39482616 80.67185178 Dec 27 1OOO 53.15416132 Y6.81M8776 66.39477961 k c 2'7 ?Ooû 51.64102109 96.65454288 6 8 . 8 8 0 9 ~ 8
Solution Mg krccnt Pprn Coppcr in Volume Cappcr Total mg Coppe Solut ion ( L ) Dissotved Coppr Dtssolvtd
4.40017341 17.60069364 0.X 4.400173 69.71921 93.69963 Ni 233003 Ni 2.61316158 1613161581 0.25 6532904 Ni 232.003 Ni 3.15106529 315.1065192 0.25 78.77663 84.34796 9339483 Ni 237003 Ni 5.5713295 1 22.2853 1803 0.3 5.57133 Ni 237003 Ni 6.60897803 660.8978033 0.25 165.2245 170.6679 96.81049 Ni 232003 Ni 5.4347337 21.773897445 0.25 5.443475 Ni 137003 Ni 5.23083598 523.083598 0.25 130.7709 t35.2972 96.65354 Ni 233003 Ni 4.52631013 t8.10524051 0.25 4.52631 Ni 232003 Ni
Perceni M g Nichl in Solurion Mg Nickl Total Nickel Nickcl samplc Volume Dissolvcd ( mg ) Disolvcd
127.88192 0 . 3 31.97198 181.0688427 82.35264 596.38135 1 0.25 149.096863 70 1 ,200969 0.25 175.300242 217.3003823 80.67185
168.00056 0.25 42.00014 527.931384 0.25 13 1.982846 198.4860767 66.49478 266.0127îJ 0.25 665031807 456.WS9 0.15 1 14.012115 1655206513 68.8809 106.034 146 0.25 515085365
Dilution Factor
4 4 4 4
100 Io0 100 Io0