North-Caucasian Mining-Metallurgical Institute, Vladikavkaz, Russia:

L. A. Voropanova, Professor, e-mail: lidia_metall@mail.ru
N. B. Kokoeva, Post-Graduate Student

The developed low-waste, effective technology for processing of zinc cakes allows a selective extraction of iron, zinc, copper, lead, gold and silver from oxidized zinc cakes. This technology consists of the following basic production stages:
• sulfatization of cakes with oleum;
• leaching of sulfate sinter with a diluted sulfuric acid solution;
• hydrochlorination of pulp;
• extraction of iron and gold from the solution with tributylphosphate after hydrochlorination;
• extraction of zinc and silver;
• re-extraction of iron and zinc from extracts with a distilled water;
• re-extraction of gold and silver with a mixture of an 8% thiourea solution and 10% HCl solution.
The technology is designed for initial extraction of iron in the first portions of extractants, as the presence of iron in the solutions suppresses the extraction of zinc, silver and — to a significantly lesser degree — gold. Furthermore, iron oxide is formed; it is suitable for further use and is an inseparable part of gold extraction technology. The processes of extraction and re-extraction are performed with portion supply of extractants and re-extractants, which lowers their consumption and increases the selectivity of metal extraction. The developed technology enables selective extraction of valuable metals at a high rate, %: 88 Zn; 77 Fe; 98 Cu; 86 Pb; 90 Au; 86 Ag. The developed technology has fewer wastes than the Waelz process. If clinker amounts to around 65–70% of the processed cake’s mass, the offered technology enables a 3–5 times lower level of solid residue, i. e., up to 10–20% of the processed cake’s mass. The residue of hydrochlorination also needs to be buried, yet it contains an insignificant amount of non-ferrous metals and can be used for technical purposes.

1. Zaytsev V. Ya. , Margulis E. V. Metallurgiya svintsa i tsinka (Metallurgy of lead and zinc). Moscow : Metallurgiya, 1985. 263 p.
2. Kozlov P. A. Velts-protsess (Waelz-process). Moscow : “Ore and Metals” Publishing House, 2002. 176 p.
3. Shivrin G. N. Metallurgiya svintsa i tsinka (Metallurgy of lead and zinc). Moscow : Metallurgiya, 1982. 352 p.
4. Alkatseva V. M. Printsipialnaya skhema pererabotki tsinkovykh kekov (Flow diagram of zinc cake treatment). Izvestiya vuzov. Tsvetnaya metallurgiya = Universities’ Proceedings. Nonferrous Metallurgy. 2014. No. 3. pp. 28–32.
5. Karelin V. A. Ekstraktsiya tributilfosfatom (Extraction by tributyl phosphate). Tomsk : Tomsk Polytechnical University, 2012. 16 p.
6. Wang Fuxing, Huang Songtao, Luo Wei, Yang Limei, Liu Xue. Extraction of Leaching Solution with Low Ni and Co Content. Xiyou jinshu (Chinese Journal of Rare Metals). 2011. Vol. 35, No. 5. pp. 753–758.
7. Zhukov S. V., Litvinova T. E., Chirkst D. E. Razdelenie zheleza (III), alyuminiya i lantanoidov ekstraktsiey naftenovymi kislotami (Separation of iron (III), aluminium and lanthanides by naphtenic acid extraction). Zapiski Gornogo instituta = Proceedings of the Mining Institute. 2012. Vol. 197. pp. 221–225.
8. Kuznetsova N. A., Shavkunova M. Yu., Sinegribova O. A. Poisk optimalnykh usloviy provedeniya protsessa ekstraktsionnogo izvlecheniya Zr v tributilfosfat iz azotnokislykh rastvorov (Search of optimal conditions of the process of Zr extraction in tributyl phosphate from nytrogen-acid solutions). Uspekhi v khimii i khimicheskoy tekhnologii = Journal Advances in Chemistry and Chemical Technology. 2011. Vol. 25, No. 7. pp. 12–16.
9. Naboychenko S. S., Ageev N. G., Doroshkevich A. P., Zhukov V. P., Eliseev E. I., Karelov S. V., Lebed A. B., Mamyachenkov S. V. Protsessy i apparaty tsvetnoy metallurgii (Processes and apparatuses of non-ferrous metallurgy). Ekaterinburg : Ural State Technical University — Ural Polytechnical Institute, 2005. 700 p.
10. Wieszczycka K. Recovery of Zn (II) from multielemental acidic chloride solution with hydrophobic 3-pyridineketoxime. Separation and Purification Technology. 2013. Vol. 114. pp. 17–23.
11. Lum K. H., Stevens G. W., Perera J. M., Kentish S. E. The modelling of ZnCl₂ extraction and HCl co-extraction by TBP diluted in ShellSol 2046. Hydrometallurgy. 2013. Vol. 133. pp. 64–74.
12. Fleitlikh I. Yu., Pashkov G. L., Grigorieva N. A., Logutenko O. A., Kopanyov A. M. Zinc extraction from sulfate-chloride solutions with mixtures of a trialkyl amine and organic acids. Hydrometallurgy. 2014. Vol. 149. pp. 110–117.
13. Kopkova E. K., Tyuremnov A. V., Gromov P. B., Neradovskiy Yu. I., Semushin V. V. Gidrokhloridnaya ekstraktsionnaya pererabotka tsinkovogo klinkera (Hydrochloride extraction processing of zinc clinker). Khimicheskaya tekhnologiya = Chemical technology. 2015. No. 3. pp. 168–175.
14. Reznik I. D., Sobol S. I., Khudyakov V. M. Kobalt (Cobalt). Moscow : Mashinostroenie, 1995. Vol. 2. pp. 91–93.
15. Voropanova L. A., Kokoeva N. B. Selektivnoe izvlechenie zheleza i tsinka iz vodnykh rastvorov tributilfosfatom (Selective extraction of iron and zinc from aqueous solutions using tributylphosphate). Tsvetnye Metally = Non-ferrous metals. 2015. No. 12. pp. 30–35. DOI: 10.17580/tsm.2015.12.05