A novel method of preparing PbS from waste lead paste through in-situ vulcanization and reduction

摘要

Lead in the Waste lead-acid batteries (WLAB) is a serious, important environmental problem if it is not properly disposed. And this is one of the issues that catches the world attention. At the same time, the waste lead is a kind of resource which is worthy of recovery. This paper proposes a new method to prepare ultrafine PbS using the main components of the lead paste in WLAB. Fully utilizing the sulfur in the PbSO4 of the lead paste, PbS can be prepared after in-situ vulcanization and reduction. A little sulfur is added for vulcanization of Pb, PbO and PbO2 in the paste, and the dosage of the sulfur can be calculated as M-S = 0.167M(Pb) + 0.25M(PbO) + 0.35M(PbO2). PbSO4 can be reduced to PbS by adding carbon. Therefore, the sulfur in PbSO4 will be kept in PbS and will not generate SO2 emission, which will be beneficial for the air protection. The mechanisms of each step are also explored in detail. This study can provide an environmentally-friendly way for recycling Pb from the WLAB with a high value-added product. (C) 2018 Elsevier Ltd. All rights reserved.