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Valorization of Solid/Liquid Wastes: A Route to Green Industrial Process
by
Dr. R. S. Somani, Senior Principal Scientist
Discipline of Inorganic Materials & CatalysisCentral Salt & Marine Chemicals Research Institute
(Council of Scientific and Industrial Research)rssomani@csmcri.org
16th October, 2014
Successful Case studies at CSIR-CSMCRI
Value addition of solid waste generated in nitro-phosphate fertilizer plant
Preparation of sodium silicate, precipitated silica and Zeolite-A from waste generated during diamond mining
Recovery of Palladium from spent silica and spent catalysts
Production of Zeolite-A from alumina waste, effluent containing AlCl3 and low grade Bauxite
Precipitated Calcium carbonate from carbide lime waste
Preparation of Synthetic Hydrotalcites from effluents discharged by Dye manufacturing units
Value addition of solid waste generated in nitro-phosphate fertilizer plant
Nitro Phosphate Fertilizer Plant
Rock Phosphate
Phosphoric Acid + Calcium Nitrate + Nitric Acid + HF
Calcium Nitrate, Tetra hydrate
ChillingPhosphoric Acid
+
Nitric Acid
+
HF
60% Nitric Acid
In 60% Ammonium Nitrate solution
Dissolution
Ammonium Carbonate
solution
Byproduct Calcium Carbonate
Ammonia
Filtration
CAN
Filtration
ANP
Drawbacks of solid waste / by-product
• Off white color
(Whiteness Index 80 – 85%)
• Coarse particle size
(20 – 150 microns)
• High bulk density
(1.32 – 1.35 g/cc)
• Alkaline pH (7.5 – 8.5)
• Low purity (CaCO3, 80 – 85 %)
• Presence of P2O5 (1.5 – 2.5%)
• Impurities identified:
Ammonium nitrate, Calcium
nitrate, Calcium tri-phosphate and
Calcium fluoride
Semi-continuous pilot plant (10kg/h) for the
production of PCC & ACC
Nitro phosphate
Fertilizer Plant Fertilizer
CaCO3 rich Inorganic
solid waste
Rotary Screw Feeder
Rotary Calciner
Rotary Cooler
Grinder
Slaker
Carbonation Tower
Filter Press
Dryer
Pulvarizer PCC or ACC
Wet Cake
Slurry Tank
Fatty acid / salt
solution
Exhaust Gases
Scrubber
CO2 Recovery &
Compression system
Air
Product Application Advantages to Fertilizer industry
• Low Raw Material Cost.
• Integration with Existing Complex –
Lower cost vis-à-vis setting up New
Plant.
• Waste Utilisation – Long Term
Solution.
• Recycling & recovery of ammonium
nitrate.
Patents Granted: US6,790,424, US6,761,864, JP2005507357T, JP2005507356T,
EP1440037, EP1440038, WO03037796, WO03037795, CN1484616, DE60108910D,
DE60108990D
Preparation of sodium silicate, Precipitated silica and Zeolite-A (detergent builder) from waste
generated during diamond mining
For mining of 10 carats of diamond, about 100
tons of solid waste (Kimberlite) is generated.
In Panna mines itself, which is mining about
58,000 carat of diamond, around 0.6 million
tones of this waste is produced every year.
Furthermore, around ~4 million tons of
kimberlite is already available from Panna
mines accumulated during previous mining.
Typically kimberlite waste is having the chemical
composition SiO2 30 – 32%, Al2O3 2 – 5%, TiO2 5 –
8%, CaO 8 – 10%, MgO 20 – 24%, Fe2O3 5 – 11%,
LOI 13 – 15%.
The major components of kimberlite waste are
magnesia and silica. The XRD patterns of the
kimberlite shows the presence of serpentine,
quartz, calcite and chlorite as major phases and
hematite, magnetite and anatase as minor phases.
Preparation of Sodium silicate, Precipitated silica and Zeolite-A from residual silica recovered from
Kimberlite
Kimberlite Waste
Acid Treatment
Acid treated kimberlite waste
(Silica rich (70-72%) residue)
Sodium Silicate
Ppt. Silica
Filtrate containing acid
soluble impurity
Treatment with NaOH
Solid containing HCl
and NaOH insoluble
material Zeolite-A
Used for preparing
Magnesium compounds and
Pigment grade Iron Oxide
Patent granted: US 7,335,342; 7,560,093; 7,037,476
Recovery of Palladium from spent silica and catalysts
United States Patent 7,108,839( 2006); 7,473,406 ( 2009)
Zeolite-A from alumina waste, effluent containing AlCl3and low grade Bauxite
PCC from carbide lime waste
Properties of Precipitated Calcium Carbonate from Carbide lime waste
Vaterite phase of CaCO3
Preparation of Synthetic Hydrotalcites from effluents discharged by Dye manufacturing units
Properties CSMC
RI -
SHT
DHT-4A
Molar ratio MgO/ Al2O3 4.2 4.0-5.0
Specific surface area
(BET) m2/gm
12 5-15
Loss on drying (105C,
1hr, %wt)
0.4 0.5 max.
Heavy metals (as pb) <10pp
m
10ppm
max.
Particle size distribution ( by number )
Mean particle size
(surface weighted) m
0.45 0.4-0.7
Under 1 m 90% 85% min.
Over 5 m None None
pH of suspension
[2%(w/v)C2H5OH:H2O(1
:1)]
9.1 9.00.5
Bulk density gm/c.c. 0.3 0.33
Halogen scavenger grade SHT
Key Innovations
Use of waste bittern as Mg source.
Reduced energy consumption.
Process simplicity.
AlCl3 spent liquor from fine chemical industries can be used.
High acid absorption capacity of pharma grade SHT.
A plant, set up by M/s Heubach Color Pvt. Ltd;
using CSIR-CSMCRI technology to manufacture
1000 Tons per annum of Synthetic hydrotalcite was
inaugurated by company’s Chairman, Mr. Rainer
Heubach on 10th October 2012. The product SHT is
prepared using effluent streams containing
aluminum, alkali generated in copper pthalocyanin
organic pigment plant of the company, and bittern
containing magnesium. The product meets the
specification of benchmark products marketed by
reputed companies. SHT finds many industrial
applications including polymer additive as halogen
scavenger, fire retardant material, as antacid
adsorbent and catalyst. The requirement is met
through import hitherto. Patent has been filed.
Inauguration of 1000TPA plant for production of Synthetic hydrotalcite (SHT)from waste
streams
CSIR-CSMCRI
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