JSC “Shchyolkovo plant of secondary precious metals”, Shchyolkovo, Russia:

S. I. Rogov, Director of Economic Affairs, e-mail: gupvdm@elnet.msk.ru

This article is devoted to development of technology of oxidizing melting silver-zinc accumulators, containing lead. There are given the results of single-stage melting of accumulators. This technology of silver isn't suitable for processing of similar products because of high losses. There is studied the behavior of lead compounds in the presence of metal and zinc vapors. It is revealed that simultaneous removal of zinc and lead is almost impossible. Therefore, two-stage melting is accepted: oxidation and zinc slagging in the presence of flux, followed by lead oxidation. Researches on studying of dynamic viscosity of used slag are conducted. Slag, based on sodium oxide and silicon dioxide, is offered to use, which melting temperature at the ratio of SiO₂:Na = 75:25 is equal to 782⁰ C. For the purpose of decrease of silver losses with flue gases, it is offered to enter integumentary fluxes at the second melting stage into mixture of 20–40% of MgCl₂ and 60–80% of NaC (3% of initial weight). Dependences of maintenance of components in draft silver are received from melting duration, and influence of melting duration on silver losses at single- and two stage swimming trunks, influence of cooling speed on change of the content of lead in draft silver at the second stage of melting. Results of two stage meltings are given. With fast hardening of material, it is possible to reach the reduction of duration of the second stage till 30 minutes. There are given the results of the second stage of melting with targeting of integumentary fluxes. Decrease in silver losses from 8.67% to 0.58% is shown. The process flow diagram is submitted by the obtained data results.

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