RECLAIMING OF LEAD IN FORM OF HIGH PURITY LEAD COMPOUND FROM RECOVERED ELECTRODE PASTE SLIME OF DISMISSED LEAD BATTERIES AND/OR OF LEAD MINERALS

摘要

An outstandingly low environmental impact wet process recovers the lead content of an electrode slime and/or of lead minerals in the valuable form of high purity lead oxide or compound convertible to highly pure lead oxide by heat treatment in oven at relatively low temperature, perfectly suited for making active electrode pastes of new batteries or other uses. The process basically comprises the following treatments: a) suspending the impure lead containing material in an aqueous bath containing at least a lead oxide dissolving acid; b) reducing any insoluble lead dioxide to lead oxide by introducing in the suspension either hydrogen peroxide, a sulphite or sulphurous anhydride; c) converting all dissolved lead oxide to lead sulphate in the aqueous bath; d) obtaining a solution of lead sulphate obtained in an aqueous solution containing an acetate salt; e) precipitating and separating a purified lead compound in the form of either carbonate/oxycarbonate or of oxide/or hydroxide by adding to said acetate salt solution a carbonate salt or a hydroxide of the same cation of said acetate salt, respectively. Exemplary flow sheets according to several alternative embodiments and related processing plant diagrams are disclosed.