JSC “UMMC-Holding”, Verkhnyaya Pyshma, Russia:

A. M. Panshin, Technical Director

Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:
S. V. Mamyachenkov, Professor, e-mail: svmamyachenkov@yandex.ru
O. S. Anisimova, Assistant Professor, Chair of Heavy Non-Ferrous Metals Metallurgy

D. Serikbayev East Kazakhstan State Technical University, Ust-Kamenogorsk, Republic of Kazakhstan:

N. A. Kulenova, Professor, Head of Metallurgy Chair

JSC “Elektrozinc”, Vladikavkaz, Russia:

I. I. Khodyko, Executive Officer

Optimization and simulation of results of laboratory experiments on leaching of calcined Waelz oxide with sulfuric acid and circulating electrolyte allowed to formulate the conditions of maximum transfer of zinc into productive solution. Using the computer program Statistica-7, the obtained data were processed in the form of models. Extraction rate of impurities in the solution depends on the zinc:acid ratio: with stoichiometric ratio of 1:1, zinc and iron hydrocompounds, inhibiting impurities output, are formed on the surface of Waelz-oxide particles. Dissolution of the film of reaction products, removing internal diffusion limitations, is observed with zinc:acid ratio of 1:1.2. Dependence of copper recovering on pH, duration and zinc:acid ratios in all series is characterized by initial induction period for the first 30 minutes of leaching. With a surface layer of iron cations (III), having oxidizing properties, equilibrium shifts towards copper cations Cu²⁺. According to this, significant amount of these cations appear in the solution. Reaching pH > 3, part of iron (Fe (III)) forms a basic salt solution and ferrous hydroxide, reducing its concentration. Formation of two fractions in the cake after leaching is substantiated by various mechanism of crystallization of calcium and lead sulphate; calcium sulfate phase is formed in the bulk solution, while lead sulfate phase is crystallized on Waelz oxide surface. At the same time, lead sulfate phase creates a film and increases both volume and density of residual cake particles. Microspectroscopic analysis showed that composition of fine fraction is dominated by zinc and calcium sulfates, whereas part of coarse fraction contains residual zinc oxide and lead sulphate. Iron, copper and arsenic oxides were found in the form of impurities (within 1%) in composition of fine and coarse fractions.

1. Panshin A. M., Anisimova O. S., Mamyachenkov S. V., Karelov S. V. Fazovyy sostav produktov veltsevaniya tsinksoderzhashchikh pyley chernoy metallurgii (Phase composition of products of Waelz processing of zinc-containing ferrous metallurgy dusts). Tsvetnye Metally = Non-ferrous metals. 2013. No. 8. pp. 51–55.
2. Panshin A. M., Lamukhin A. M., Zinyagin G. A., Skurdin F. L., Kozlov P. A., Dyubanov V. G., Leontev L. I. Razrabotka tekhnologii pererabotki tsinksoderzhashchey pyli elektrodugovykh pechey s polucheniem syrevogo produkta dlya polucheniya metallicheskogo tsinka (Development of technology of processing of zinc-containing dust of electric arc furnaces with stock obtaining for metallic zinc production). Ekologiya i promyshlennost Rossii = Ecology and industry of Russia. 2013. No. 1. pp. 4–6.
3. Panshin A. M., Kozlov P. A., Ivakin D. A., Vyatkin V. N. Analiz otgonki tsinka, svintsa i olova v veltspechi pri pererabotke pylevidnykh polimetallicheskikh promproduktov mednoy promyshlennosti (Analysis of zinc, lead and tin distillation in Waelz-klin in the time of processing of dust-like polymetallic copper industry middlings). Tsvetnye Metally = Non-ferrous metals. 2013. No. 8. pp. 41–45.
4. Panshin A. M., Kozlov P. A., Leontev L. I., Dyubanov V. G., Zatonskiy A. V., Ivakin D. A. Tekhnologiya pererabotki pyli elektrodugovykh pechey Otkrytogo Aktsionernogo Obshchestva “Severstal” v veltskomplekse Otkrytogo Aktsionernogo Obshchestva “Chelyabinskiy Tsinkovyy Zavod” (Technology of processing of dust of electric arc furnaces of JSC “Severstal” in Waelz-complex of JSC “Chelyabinsk Zinc Plant”). Ekologiya i promyshlennost Rossii = Ecology and industry of Russia. 2012. No. 11. pp. 4–6.
5. Rozovskiy A. Ya. Kinetika topokhimicheskikh reaktsiy (Topochemical reaction kinetics). Moscow : Khimiya, 1974. 220 p.
6. Kakovskiy I. A., Khalezov B. D. O kinetike rastvoreniya okisi tsinka v vodnykh rastvorakh sernoy kisloty (About the kinetics of dissolution of zinc oxide in water dissolutions of sulfuric acid). Izvestiya vuzov. Tsvetnaya metallurgiya = Russian Journal of Non-Ferrous Metals. 1977. No. 2. pp. 26–31.
7. Nikolaeva R. B., Pashkov G. L., Saykova S. V. Izuchenie mekhanizma kislotnogo i sorbtsionnogo rastvoreniya oksida tsinka metodom vrashchayushchegosya diska (Research of mechanism of acid and sorption dissolution of zinc oxide by rotary disc method). Zhurnal fizicheskoy khimii = Russian Journal of Physical Chemistry. 1995. Vol. 69, No. 12. pp. 2200–2203.
8. Guspiel V., Riesenkampf W. Kinetic of dissolution of ZnO, MgO and their solid solutions in aqueous sulphuric acid solutions. Hydrometallurgy. 1993. Vol. 34, No. 2. pp. 203–220.
9. Gorichev I. G., Kipriyanov N. A. Kineticheskie zakonomernosti rastvoreniya oksidov metallov v kislykh sredakh (Kinetic regularities of dissolution of metal oxides in acid mediums). Uspekhi khimii = Russian Chemical Reviews. 1984. Vol. 53, Iss. 11.
10. Kakovskiy I. A., Potashnikov Yu. M. Kinetika protsessov rastvoreniya (Kinetics of dissolution processes). Moscow : Metallurgiya, 1975.