Facile method for preparing a nano lead powder by vacuum decomposition from spent lead-acid battery paste: leaching and desulfuration in tartaric acid and sodium tartrate mixed lixivium

A facile method for the desulfuration of a waste lead-acid battery paste was proposed, in which tartaric acid-sodium tartrate was used as the leaching agent to yield lead tartrate [(C4H4O6) Pb], which was further vacuum decomposed. First, lead paste was transformed into lead tartrate with a desulfuration efficiency of 99.51% under the optimum conditions: an n(C)(4H6O6): n(C)(4H4O6Na2) ratio of 1:1.5, an n(P)(b): n(C)(4H4O6)(2-) ratio of 1:2, a liquid-solid ratio of 6:1, a temperature of 70 degrees C, and a reaction time of 3 h. The purity and average size of the lead tartrate product approached 99.80% and 20.75 mu m. The vacuum decomposition of lead tartrate yielded nano lead and lead oxide powder at different temperatures; nano lead powder was generated at 290 degrees C, and the content of PbO in the decomposition products increased with the increasing temperature and reached 98.6% at 480 degrees C. All the decomposed particles were made of spherical nanoscale particles with a uniform size of approximately 100 nm. The main advantages of this process are that it employs a facile and nontoxic lixivium and the nano lead powder is directly produced by vacuum decomposition.