Ural Mining and Metallurgical Company, Verkhnyaya Pyshma, Sverdlovsk Oblast, Russia

A. M. Panshin, Technical Officer

“Chelyabinsk Zinc Plant” JSC, Chelyabinsk, Russia

P. A. Kozlov, Head of Engineering Center, e-mail: pak@zinс.ru
D. A. Ivakin, Head of Technological Bureau of Engineering Center
V. N. Vyatkin, Leading Processing Engineer of Engineering Center

Processing of difficult chemical products (dusts) of copper industry is very actual for the purpose of extraction of copper, precious metals, zinc, lead and iron. The usage of Waelz process makes it possible to transform zinc, lead and tin from the foregoing raw materials into Waelz oxide. Taking into account the chemical and mineralogical content of raw materials, it is necessary to develop the conditions for efficient extraction of the considered metals. There are considered the thermodynamic characteristics of the processes, taking place with zinc, lead and tin compounds in the conditions of Waelz kiln during the processing of charge on the basis of copper industry middlings. According to the phase analysis, the basic amount of zinc in raw materials has the oxide and sulphide form; the amount of lead has the sulfate form; and the amount of tin has the oxide form. There is shown the possibility of interaction of calcium oxide, zinc and iron sulphides and hydrogen (which is formed during the feeding of water vapour into the furnace) with zinc, lead and tin compounds with following distillation of metals (at the process temperature of 1500–1573 K). The most important factor for the technology development is distillation of lead without its recovery up to the metallic state, because metals accumulation in the rotary furnace leads to the failure of Waelz process. On the basis of experimental data, there are considered the mechanisms of the processes kinetics. According to the data processing, on the basis of the generalized level of heterogeneous reactions, there are defined the activation energies of lead and tin sublimation processes, which contain 63–77 kJ/mole and 66–100 kJ/mole, which corresponds to kinetic and combined area of reactions. The practical application of the considered reactions in Waelz-kiln makes it possible to do the following operations:
— selection of optimal content of charge;
— intensification of the process of non-ferrous metals distillation;
— decreasing of the consumption of reducer (coke fines), which is supplied with raw materials.

1. Kozlov P. A., Kolesnikov A. V. Tsvetnye Metally — Non-ferrous metals. 1995. No. 4. pp. 55–56.
2. Kozlov P. A. Velts-protsess (The Waelz process). Moscow : “Ore and Metals” Publishing House, 2002.
3. Baram I. I. Makrokinetika geterogennykh protsessov (Macrokinetics of heterogenous processes). Alma-Ata : Nauka, 1986. 208 p.