Slime from sulfuric acid shop of Balkhash copper-smelting factory – alternative source for production of selenium at the enterprise. Review

Abstract

The article covers the problems of possibility for involving selenium from the slime of the sulfuric acid shop of the Balkhash Copper Smelting Plant (BCSP) into the sphere of its production. At pyrometallurgical processing of copper charge, selenium is sublimated and distributed among four waste products: washing sulfuric acid, slimes of sulfuric acid and electrolyte shop, and electrofilter dust. In the world, the main raw material for the production of selenium is copper electrolytic sludge (90 %) and sludge of sulfuric acid production of the chemical and pulp and paper industry (10 %). A comparative analysis of selenium content in the slimes of the metallurgical, chemical and pulp and paper industries showed that the content of selenium in the slimes of the sulfuric acid shops of the BCSP and “Kola Company” JSC is identical and much higher than in copper electrolytic slimes – the main source of selenium in the world. The qualitative, quantitative, granulometric and material compositions of the slime of the BCSP’s sulfuric acid shop are presented. It contains Pb, Se, Re, Al, Si, S, Ca, Fe, Cu, Zn, Sr, Cd, I, Hg, Ni, Br, Bi, As, Sb, Ag, Cr, Mg, Mo, Ti, Mn, and organic compounds (presumably, aliphatic acids). The content of some elements is several tens of percent, others – hundredths of a percent. Interest for the recovery is Se (4.6–32.3 5 wt. %), and furthermore are Re (0.14 wt. %), I (0.33 wt. % Hg (0.57 wt. %). Slime-forming element is lead in the form of its sulfate. Into the size class -0.4 + 0 the following are recovered Pb – 47.84 %, Se – 47.45 %, Re 55.31 %. The content of the elements in classes of different sizes is almost identical: Pb (56.7-58.1 wt. %), Se (4.00-4.51 wt. %), Re (0.10-0.16 wt. %.). Selenium in the slime is in the forms of the elemental – of three modifications, lead selenate and a substance containing the selenite anion. With the slime disposed to sewage treatment plants, 30-40 % of selenium, produced from copper electrolyte slime in Balkhash, is lost. Following facts are a strong argument for involving these slimes into the sphere of selenium production. They are the high content of selenium in slime of sulfuric acid shop, in perspective taken out as an independent product when introducing the technology of rhenium extraction from washing solutions, the presence of selenium production at the plant and the predicted selenium deficit in the world due to introduction of new technologies.