METHOD FOR PROCESSING OF PASTE BY WASTE LEAD- ACID BATTERY

摘要

The method will be used for high-productivity lead extraction in hydrometallurgy. The method uses three processes: desulphurisation, leaching and electro winning. Desulphurisation is carried out in an inert or reducing gas medium at pressures of 2-6 MPa in two stages: at 30-35 and 55-75 degree C, respectively, each of the stages lasting 20-40 minutes, using a stoichiometric quantity of a saturated solution of sodium carbonate and adding, in equal portions, sodium hydrogen carbonate and sodium hydrogen sulphite at liquid/solid phase ratios between 4:1 and 8:1. Leaching is carried out using silicofluoric acid and phosphorous acid in the amount of 40 percent of the plumbous oxide in the desulphurised product. Electrowinning extraction is carried out finally with the electrolyte containing, in g/l: lead 30-80 and silicofluoric acid 8-120, using graphite anodes and a periodic reverse current with density of the normal current pulse 200-300 A/m<2> and duration 10-60 seconds, while the density and duration of the reversed current pulse are, respectively, 5-100 percent and 1-2 percent of the normal current pulse with a duration of the cathode cycle 48-96 hours.