INCREASING THE RATE OF TIN DISSOLUTION IN AN ALKALINE MEDIUM

摘要

Tin production from scrap and tin plate wastes is based on alkaline hydroelectrometallurgical technology, the main shortcoming of which is the low productivity of the detinning operation. Therefore there is practical interest in seeking ways to increase the efficiency of tin regeneration by accelerating the stripping of tinplate. In an earlier work, using the rotating electrode method, a detailed study was made into the dissolution of metallic tin in relation to the concentration of alkali, metanitrobenzoic acid (MNBK), the temperature, and application of current. This work provides the results obtained from determining the rate of tin dissolution under conditions approximating the industrial processing of tin-containing scrap. For this, a stationary electrode was used and the concentration of basic components was maintained in accordance with the composition of the industrial solution used for detinning. Basic attention was given to evaluating the effect of the application of anodic current on the tin dissolution rate, since in USSR regenerating units the detinning of tin wastes is conducted both chemically (a separate flowsheet) and electrochemically (combined systems). Chemical dissolution was conducted in a glass thermostatic vessel, 0.5 dm~3 in capacity. Cylindrical specimens, cast from specially pure granulated tin, were charged vertically and attached securely. Forced convection was created by a glass mixer (n = 60 rpm). Air was fed by a compressor and sprayed by the Schott filter. For electrochemical dissolution, TEC-42 stabilizing rectifiers and cells with diaphragms made from baked glass were used.