Varta process

This is typified by the Varta process implemented by Varta Batterie AG at Hannover, Germany and as used by Boliden-Bergsoe AB at Landskrona, Sweden. The batteries are drained and charged with fluxes (lime, silica and shredded scrap iron), coke and an amount of recycle lump slag. The slag has a melting point above 1000°C and maintains an open structure in the shaft until it nears the tuyere zone with a temperature of around 1150°C. 

Water is evaporated in the upper part of the shaft, followed by decomposition of the plastic components as the temperature rises to 500°C. Lead also melts and reacts with Pb02 to form PbO. This is reduced by CO to lead further down the shaft, and sulfates are reduced to PbS. A feature of the Varta process is the use of metallic iron to react with PbS and form lead and FeS as a matte, thus capturing the majority of the sulfur in feed. 

Koch, M and Niklas, H, 1989. Processing of lead-acid-battery scrap The Varta process, in Proceed/ngi Minerals, Metals and Materials Society (TMS) Symposium on Productivity and Technology in the Metallurgical Industries, Cologne, September, pp 495-500 (The Minerals, Metals and Materials Society (TMS) ... 

Figure 19.2 Schematic diagram of toe charging process in seaied nickei-cadmium batteries with negative charging reserve (Courtesy of Varta)...

Figure 19A Schematic diagram of the discharge process in sealed nickel-cadmium batteries with antipoiar mass in the positive electrede (Ceurtesy of Varta)...

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