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The main process parameters have been investigated with a relatively new method for lead recovery from oxidic paste. The method consisting in leaching with NaOH and is also useful for processing other secondary resources (volatile dusts resulted from metallurgical extraction of lead from primary resources). The chemical analysis and X-ray diffraction have attested that the oxidic paste resulted from the dismantling of spent lead-acid batteries has a content of 70–73% Pb, mainly as anglesite (around 38% PbSO4) and lanarkite (about 36% Pb2SO5). Experiments have been carried out through leaching with NaOH of the industrial paste out of spent car batteries as well as for the pure substances. The experiments were conducted at temperatures of 40, 60 and 80 °C, at various solid/liquid ratios (S : L = 1 : 10; 1 : 30 and 1 : 50) and different molarities for the NaOH solutions (2, 4, 6 and 8 M). The reaction time was 1 h for the leaching of the pure substances and 2 h for the leaching of the industrial pastes. An extraction efficiency of 92% Pb was obtained with a leaching solution of 6 M NaOH, at 60 °C, for 2 h and S/L ratios of 1 : 20–1 : 30. The efficiency may be increased up to 97% Pb only when the leaching process is carried out in two steps. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd. |
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