Method for desulphurization of battery paste

摘要

The invention relates to a method of desulphurizing battery paste in the process of recycling lead-acid batteries. The paste desulphurizing stage of the method according to the invention is carried out in an aqueous solution of a defined amine or of a mixture of polyamines, wherein the said solution is saturated with carbon dioxide to remove the remainder of calcium from the solution and then filtered to isolate precipitated calcium carbonate, preferably by using pressure filtration, thereafter the battery paste is leached with the thus obtained circulating aqueous solution of the polyamine or of a mixture of polyamines, followed by filtration of the suspension obtained, preferably by using pressure filtration and washing on the filter, to obtain a desulphurized paste of low sulphur content and the circulating solution. The solution is regenerated by removing therefrom the remainder of lead and carbon dioxide by acting upon it with sulphuric acid and then filtered to separate lead sulphate and recycled to the basic process. The circulating amine solution is regenerated with calcium hydroxide in a crystallizer to obtain a gypsum suspension, which is separated by pressure filtration and washed on the filter to produce gypsum and the circulating solution, wherein the concentration of the polyamine or of the mixture of polyamines in the solution is adjusted by admixing a new portion of the polyamine or of the mixture of polyamines, and the adjusted solution is returned to the start of the process.