Download - Coal Gold Agglomeration
![Page 1: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/1.jpg)
COAL-GOLD AGGLOMERATION
GROUP ONE
COPYRIGHT © 2011, C.O.B
![Page 2: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/2.jpg)
Environmental protection has become the
focus of world-wide researches in the gold mining industry and favors the development of environmentally sound processes, such as the Coal-Gold Agglomeration (CGA) process, which is an alternative to existing gold processing methods, such as cyanidation and mercury amalgamation.
INTRODUCTION
![Page 3: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/3.jpg)
This process of gold recovery was developed
and patented by the British Petroleum (BP) research team in the early eighties and was to replace the old hazardous forms of mining; and has an advantage over the other methods of gold mining, in that gold is recovered by a procedure which has little or no negative impact on the environment, low operation as well as low cost involvement.
![Page 4: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/4.jpg)
The gold mining industry especially the small-
scale mining industry has relied mainly upon the use of highly polluting chemicals, such as mercury and cyanide to recover gold from its ores. These methods of gold mining pose considerable hazards to the environment due to the effects these chemicals have.
![Page 5: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/5.jpg)
The process is based on the recovery of
hydrophobic gold particles from ore slurries into agglomerates formed from coal and oil. The oils often used in this process include diesel oil, kerosene and vegetable oils. The oil acts as the bridging liquid between the coal and gold particles where the coal is the carrier of the mineral and enables effective separation of the oil phase.
![Page 6: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/6.jpg)
The coal-oil agglomerate is prepared by
mixing coal powders of the size of 0.074 to 0.149 millimeters and diesel oil of dosage 15% - 30% in mass.
COA PREPARATION AND GOLD RECOVERY
![Page 7: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/7.jpg)
CGA process can be applied for extracting
gold from hard (rock) ore, alluvial ore and other gold bearing ore which are difficult for cyanidation process because of high copper or arsenic content, and difficult for gravity process because of small gold particle size and certain refractory gold ores as well.
![Page 8: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/8.jpg)
In this process of gold recovery, the slurry is
burned causing the gold to form larger particles that can be extracted using gravity methods using water (i.e. flotation)
![Page 9: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/9.jpg)
This can be done in the lab by putting a weighted milled
ore into an adhesion tank. Water is then added to form the pulp. The pH of the resulting pulp is adjusted by the addition of
sodium carbonate or sodium silicate. Collectors are added successively and respectively and
pulp is stirred. COA is then put into the tank and mixed. Separation of COA from pulp is performed by filtration and
froth floatation. After adding flocculants , the residual pulp is filtered . The filtered cake is dried and sample is taken for analysis.
EXPERIMENTAL PROCEDURE
![Page 10: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/10.jpg)
After the crushed gold-bearing ores have been passed
through a ball mill, many gold particles can be liberated or exposed from the gangue mineral. When the gold particle and the other minerals associated with them become hydrophobic (i.e. by means of PH modification, addition of collectors, depressants and activators), coal-oil agglomerate (COA) can easily capture the oleophilic gold particles and the other minerals associated with them. The COA then is burnt and the resultant residue is smelt to produce gold bullion or extracted by hydrometallurgical method to produce purer gold product.
INDUSTRIAL PROCEDURE
![Page 11: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/11.jpg)
The coal-oil agglomerates are recycled to
increase their gold loading, after which they are separated and further treated to produce gold bullion or bars of gold.
A flow diagram of the whole experimental setup is found on slide 13.
![Page 12: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/12.jpg)
When the chief gold bearing minerals are
sulphides such as pyrite , yellow arsenic etc. , (although the gold recovery is high) the consumption of coal-oil agglomerate would be too high for the process to be economical.
The works carried out in the CGA process can recover gold effectively from many kinds of gold bearing minerals and can be operated successfully in commercial scale.
![Page 13: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/13.jpg)
Figure 1—A Simplified flow diagram of the Experimental Setup of theCoal Gold Agglomeration (CGA) process
![Page 14: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/14.jpg)
Laboratory scale batch tests were performed
on artificial mixture gold slurry and gold recoveries of up to 85% were found under optimized conditions. By recycling the coal/oil phase, it was found that the gold loading onto the agglomerates was increased.
EXPERIMENTAL EVIDENCE
![Page 15: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/15.jpg)
• The ground size of the ore: gold recovery
increase with ground size becoming small (high surface area).
• The pH value of the pulp: pH of the medium should be basic. The favorable pH is about 9 and this is obtained by adjusting the pH of pulp using sodium carbonate.
• The time of adhesion: The speed of gold recovering in CGA process is extremely rapid and keep constant with time.
• The stirring strength : increasing stirring increases rate of precipitation in a saturated solution.
EFFECTS OF TECHNOLOGICAL FACTORS ON GOLD RECOVERY.
![Page 16: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/16.jpg)
The coal gold agglomeration (CGA) process is
a novel gold recovering technique, which has following advantages.
Studies on gold recovery from amalgamation tailings by CGA process shows that about 88% gold can be captured by coal-oil agglomeration and the gross gold recovery is more than 85%.
ADVANTAGES OF USING CGA
![Page 17: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/17.jpg)
The gold particle from the fine (minus 5
micrometers) to the coarse (plus 300micrometers) can be recovered effectively.
The short residence time and low reagent consumption lead to a low capital and operation cost comparing with tradition cyanidation and mercury amalgamation processes.
ADVANTAGES OF USING CGA
![Page 18: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/18.jpg)
The high selectivity can be achieved against
gangue sulphide, minerals by depressants and pH modification, as in froth floatation.
No cyanide or mercury is needed; therefore the process has good environmental protection.
Silver and platinum group metals can also be recovered.
ADVANTAGES OF USING CGA
![Page 19: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/19.jpg)
Tests performed on an industrial ore yielded
slightly lower gold recoveries, and X-ray Diffraction (XRD) analysis on the coal/oil phase showed that minerals other than gold was recovered into this phase.
CHALLENGES OF CGA
![Page 20: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/20.jpg)
A comparative study conducted whereby the
CGA process was compared to mercury amalgamation showed that, Gold recoveries obtained through amalgamation were 15% lower than by the agglomeration process, which indicates that this process is relatively better.
CONCLUSION
![Page 21: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/21.jpg)
1. HUGHES-NARBOROUGH, C., WALL, N.C., and WILLEY, G. Coal Gold Agglomeration: An innovative approach to the recovery of gold in environmentally sensitive areas, IV International Mineral Processing, vol. 2, 20–22 October 1992.
2. HOUSE, C.I., TOWNSEND, I.G., and VEAL, C.J. Separation Process. Pat. Int. Cl (4) C22B1/16, /GB87/00480, w088/00248 (1988).
HOUSE, C.I., TOWNSEND, I.G., and VEAL, C.J. Separation Process. Pat. Int. Cl(4) C22B1/16, /GB87/00480, w088/00248 (1988).
3. BONNEY, C.F. Coal Gold Agglomeration—A novel Approach to GoldRecovery; Randol Gold Forum 88, Scottsdale, Arizona, 23–24 January1988.
4. HOUSE, C.I., TOWNSEND, I.G., and VEAL, C.J. Coal Gold Agglomeration,International Mining, September 1988.
5. BUCKLEY, S.A., HOUSE, C.I., and TOWNSEND, I.G. A Techno-EconomicAssessment of the Coal Gold Agglomeration Gold Recovery Process, TheCanadian Mineral Processors Conference, Ottawa, January 1989.
REFERENCE
![Page 22: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/22.jpg)
MESSRS ;
KOPGLI ROLAND
KWAKYE SAMUEL
ANANE BOATENG JOHN
DOMFEH AUGUSTINE
ANDERSON RICHARD
WILSON EBENEZER
AGLUBI YAW MANASEH
MEMBERS
![Page 23: Coal Gold Agglomeration](https://reader038.vdocuments.us/reader038/viewer/2022102901/55370a66550346640d8b4b34/html5/thumbnails/23.jpg)
THANK YOU