Lead paste desulphurization
The benefit of the desulphurization of paste is the extreme diminution of SO2 emission and the production of slag reduced down to less than 10% of produced lead. The productivity of the smelting furnace is increased due to a lower quantity of reagents and fluxes to be added to the process.
The paste slurry is pumped into a reaction tank and it is mixed with the waste acid collected in the battery storage area. The desulphurization reaction can be carried out through addition of the Sodium Carbonate, or Sodium Hydroxide or Ammonium Bicarbonate.
The reacted paste slurry is pumped to the filter-press for dewatering then the paste cake is discharged in a dedicated area ready for smelting, while the filtrated sulphate solution is conveyed to the subsequent treatment for removal of heavy metals. The purified sodium sulphate solution, separated by a further polishing filter press, is sent to sulphate salt production unit.