The Ural State Mining University, Ekaterinburg, Russia:

A. M. Amdur, Head of the Chemistry Department, e-mail: engineer-ektb@rambler.ru
S. A. Fedorov, Student, e-mail: saf13d@mail.ru
A. N. Matushkina, Post Graduate Student, e-mail: annamat87@mail.ru
R. A. Apakashev, Professor of the Chemistry Department, e-mail: parknedra@yandex.ru

Considerable part of the world's reserves of gold is accumulated in refractory ores, which contain a dispersed gold as inclusions in sulphides and silicates. The dispersed gold extraction from refractory ores and anthropogenic objects by well-known ore-dressing methods requires a preliminary enlargement of gold parts. Here the purpose is to analyze processes leading to a dispersed gold coarsening in the course of ore heating. The object of investigation is silicate-carbonate gold-bearing ore. Gold in the ore is associated with pyrite and arsenopyrite and is also contained in quartz and hard iron minerals. It cannot be extracted by cyanidation. It is experimentally determined that dispersed drops of the molten gold move towards ore surface through pores under the action of thermocapillary pressure on being heated by external heat source. After the enclosing rock melting, drops of gold are floated by gas bubbles. A condition of the drops of gold flotation in oxide melt has been analyzed. It is noted that drops of gold coagulate in the process of flotation. As a result, gold concentrates on the oxide melt surface. At the same time, the gold particles enlargement up to the sizes permissive to extract the given metal by gravity methods takes place. Method of thin gold extraction, including material heating, melting, grinding after cooling and enrichment by gravity method with the use of a KNELSON centrifugal concentrator has been realized in laboratory conditions. This has allowed to increase the yield from 13% for an initial material to 33% after its thermal treatment, especially on narrowing the size grades of particles and on separate enrichment of the close-cut fractions. In the latter case the most part of gold is extracted by cyanidation.

The work was performed within the framework of the project part of the Ministry of Science and Education of the Russian Federation state order.

1. Leonenko N. A., Kuzmenko A. P., Peterson M. V., Kuzmenko N. A. Lazernaya aglomeratsiya ultradispersnogo zolota iz mineralnykh i tekhnogennykh assotsiatsiy vysokoglinistykh peskov (The superdispersed gold laser agglomeration out of the mineral and anthropogenic high-clayey sands associations). Zapiski Gornogo Instituta = Journal of Mining Institute. 2007. Vol. 171. pp. 113–116.
2. Leonenko N. A., Kuzmenko A. P., Kuzmenko N. A. Izvlecheniye ultradispersnykh blagorodnykh metallov iz mineralnykh sred pri impulsnom lazernom vozdeystvii (The superdispersed noble metals extraction from mineral surroundings under the pulsed laser exposure). Gorny informatsionno-analiticheskiy byulleten (nauch no-tekhnicheskii zhurnal). GIAB. Otdelnyi vypusk. Dalniy Vostok = Mining Informational and Analytical Bulletin (scientific and technical journal). Fascicle. The Far East. 2007. No. 9. 584 p.
3. Galustyan L. A. Tekhnologya izvlecheniya kolloidnogo zolota iz proizvodstvennykh i stochnykh vod zolotoizvlekatelnykh fabric (Technology of gold extraction from manufacturing water and sewage of goldextractant factories). Gornyi Zhurnal = Mining Journal. 2003. No. 2. pp. С. 61–62.
4. Moiseenko V. G., Ostapenko A. F., Mironiuk A. F. Netraditsionnyy podkhod k otrabotke tekhogennykh zolotosoderzhashchikh rossypey (A nonconventional approach to testing of anthropogenic gold-bearing placers). Gornyi zhurnal = Mining Journal. 2006. No. 4. pp. 66–68.
5. Kuzmenko A. P. et al. Sposob vydeleniya ultradispersnykh i kolloidno-ionnykh blagorodnykh vklucheniy iz mineralnogo syriya i tekhnogennykh productov i ustanovka dlya ego osushchestvleniya (Method of the superdispersed and colloid-ionic noble inclusions separation from mineral raw material and anthropogenic products and a plant for its realization). Patent RF, No. 2541248. IPC МПК C22B11/02, C22B9/22. Asserted 27.01.2014. Published 10.02.2015. Bulletin No. 4.
6. Leonenko N. A. et al. Sposob izvlecheniya dispersnogo zolota iz zolotosoderzhashchego vysokoglinistogo mineralnogo syriya (Method of the dispersed gold extraction from gold-bearing high-clayey mineral raw material). Patent RF, No. 2413779. IPC C22B11/02, B22F1/00. Asserted 07.04.2010. Published 10.03.2011. Bulletin No. 7.
7. Guzev M. A. et. al. Sposob povtornoy razrabotki rossypnykh mestorozhdeniy (Method of the gravel deposits re-development). Patent RF, No. 2457330. IPC E21C41/30. Asserted 20.01.2011. Published 27.07.2012. Bulletin No. 21.
8. Matushkina A. N., Amdur A. M., Gazaleeva G. I., Vlasov I. A. Sposob izvlecheniya zolota iz trudnoobogatimykh rud s pomoshchiyu temperaturnoy obrabotki (Method of extracting gold from refractory ores with temperature treatment). Izvestoya vuzov. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2014. No. 5. pp. 129–132.
9. Amdur A. M., Vatolin N. A. Kinetika vytekaniya metallicheskykh kapel iz poristogo tela (Kinetics of the gold drops leaking out of the porous body). Rasplavy = Melts. 1991. No. 5. pp. 105–107.
10. Abramov A. A. Flotatsionnye metody obogashcheniya : uchebnik dlya vuzov : 3-e izdaniye (Flotation methods of concentration : Reference book for high schools : Third edition). Moscow : Izdatelstvo MGTU, 2008. 710 p.
11. Deryagin B. V., Tchuraev E. V., Muller V. M. Poverkhonstnye sily (The surface forces). Moscow : Nauka, 1985. 398 p.
12. Sedelnikova G. V. Mirovaya praktika pererabotki upornykh zolotosulfidnykh rud i kontsentratov (International practice of refractory gold-sulphide ores and concentrates processing). Vestnik Kazakhstanskoy natsionalnoy akademii estesvennykh nauk. Plaksinskie chteniya – 2014 = Bulletin of the Kazakhstan National Academy of Natural Sciences. Plaksin readings – 2014. 2014. No. 3. pp. 42–44.