industrial application of radioisotopes in zimbabwean industries€¦ · 28-04-2017 · industrial...

Industrial application of radioisotopes

in Zimbabwean industries Peter Baricholo

National University of Science and Technology, Department of Applied Physics, P. O. AC939, Ascot, Bulawayo, Zimbabwe

[email protected]

www.nust.ac.zw

VIC, Vienna, Austria, 24 – 28 April 2017

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mailto:[email protected]

Introduction

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Zimchem Refineries

Group Members Dr. B. Muchono Mr R. T. Mashingaidze Mr W. Chirume Mr. C. Dzingai Eng. S. Mudono

Outline

• Introduction

• RTD experiment at PPC

• RAF1004 Final coordination meeting

• Environmental Gamma Radiation Monitoring at Power Plant

• NDT activities

• Preparations for Gamma column scans

• Conclusions

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Raw mill 13.5m long and 4.2m in diameter at the factory

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RTD Experiment at PPC

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RTD Experiment at PPC Radiotracer preparation

• The preparation of the radioactive tracer was conducted in a laboratory

at PPC Colleen Bawn.

• The radioactivity was of approximately 200 mCi in solid metal form of 198Au.

• To prepare the solid 198Au; an acid solution composed of 1 part of

concentrated HNO3 by volume and 3 parts of concentrated HCl by

volume was used.

• Aqua Regia solution which was allowed to react for approximately 30 min

to form a yellow solution to that it dissolves metal gold.

• The gold in metal form was submerged into the solution and allowed to

stand for an hour to dissolve.

• After the gold was dissolved, it was further diluted with ethanol to a

volume of 80 ml.



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Experiment 1: 1 kg of limestone with 40 ml of the gold solution with a total

activity of app. 100 mCi 198Au tracer. The material feed rate was 90 t/h.

Experiment 2: 1 kg clay with 20 ml solution with app. 50 mCi of 198Au. The

material feed rate was 90 t/h.

Experiment 3: 1 kg of limestone labelled with 20 ml solution with an

activity content of appx. 50 mCi of 198Au. The feed rate was 85 t/h.

Concentration of tracer using sensitive scintillation detectors placed at

appropriate positions along the mill system as a function of time was

recorded.


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Radiotracer was introduced to the end of the raw material conveyor belt, with

the three detectors placed in three different zones, i.e.:

Detector D1: at the mill inlet for recording the zero time of tracer entering the

mill,

Detector D2: at the mill outlet,

Detector D3: at the separator outlet for recording the material that returns to

the mill entry for regrinding.



0

5000

10000

15000

20000

25000

30000

35000

40000

0 250 500 750 1000 1250 1500

Recirculation

Output pulse

Co

un

tsp

er s

eco

nd

Time in seconds

Limestone (Flow rate = 90 T/hr)

Experiment 1

Experiment 2

The mean residence time through the mill

was calculated as 8.27 min and can be

considered as representative.

The mean residence time from the inlet

pulse to the detector on the recycle line is

8.74 min.

The MRT of the clay is much quicker than that

of limestone, which can be attributed to the

particle size which creates less resistance

against the material flow and grinding process.

RTD experimental results


The MRT at outlet of mill is

3.36 min, and the transit

time of the material from

the outlet of the mill to the

recycle line is 2.14 min. 8

10

0

5000

10000

15000

20000

25000

30000

35000

0 250 500 750 1000 1250

Output pulse

Recirculation

Co

un

ts/s

Time/s

Limestone (Flow rate = 85 T/hr)

Experiment 3

RTD experimental results

The MRT from the inlet

of the mill (40.9s) to the

outlet (330.83s) is

relatively fast at 4.83

min, in comparison with

90t/h (8.27min).

Results show that the grinding process of raw materials inside the mill is not optimal; it

seems that:

1. the dynamic behaviours of limestone and clay are different, clay spends less time

inside the mill compared to limestone (for the same regime),


2. clay dynamics inside the mill was abnormal; there was a portion

of clay particles that moves faster from the input to the exit

bypassing the grinding process (or short-circuit).

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10

RAF1004 Final Coordination Meeting


Environmental Gamma Radiation Monitoring at Power Plant

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Onsite monitoring stations at the thermal power station.


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Experimental set up for taking measurements on raw coal.

Experimental set up for

taking measurements on

fly ash and bottom ash mixture.

Radon monitoring in coal and fly ash of a small thermal power plant

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0

50

100

150

200

250

300

0 100 200 300 400 500 600 700 800 900

Ac

tivit

y (

cp

s)

Time (s)

Detector 1 on Ash

Detector 2 on Ash

Detector 1 on coal

Detector 2 on coal

0

50

100

150

200

250

1 2 3 4 5

Acti

vit

y (

cp

s)

Day of experiment

Ash

Coal

Average activity

of raw coal and

ash for 5 days

Activity of raw coal and ash

measured on 18/03/2016

Radon monitoring in coal and fly ash of a small thermal power plant


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NDT Activities


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Gamma Column Scanning Activities

Zimchem Refineries

Zone zero refinery

Plant process Crude Benzole and Crude Tar


• Zimchem was formed in 1989

and the refinery was

commissioned in 1993.

• The refinery produces Crude

Benzole and Crude Tar used to

manufacture Road Tars, Pitch,

Coal Tar Fuels, Heavy Furnace

Fuels, Creosote (a wood

preservative) and industrial

solvents such as Benzene,

Toluene Xylene and

Naphthalene.

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We are currently in the

process of preparing to

carry out the gamma column

scanning experiment at the

refinery.

Gamma Column Scanning Activities at Zimchem Refineries


Some of the solvents are

used to make a wide range

of industrial chemicals and

detergents, such as

thinners, Contact Adhesives, Agrochemicals, etc.

NATIONAL UINVERSITY OF SCIENCE AND

TECHNOLOGY

industrial application of radioisotopes in zimbabwean industries€¦ · 28-04-2017 · industrial...

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