Abstract: A method for removing sodium polysulfide from used sodium/sulfur batteries provides that the cells are granulated under protective measures, the scrap is treated in a solution of sodium cyanide and the solution obtained is treated with air. The solution then contains sodium thiocyanate and sodium hydroxide, which latter can be reacted by means of CO.sub.2 to Na.sub.2 CO.sub.3, precipitated and separated.

Abstract: A method of treating solid hazardous wastes containing unacceptable levels of leachable metals such as lead, cadmium and zinc includes mixing the solid waste with a buffering agent selected from the group consisting of magnesium oxide, magnesium hydroxide, reactive calcium carbonates and reactive magnesium carbonates, and with an additional agent which is an acid or salt containing an anion that forms substantially nonleachable forms of the metals, which additional agent is selected from the group consisting of triple superphosphate, ammonium phosphate, diammonium phosphate, phosphoric acid, boric acid and metallic iron so that under both acidic and nonacidic leaching conditions the metals in the mixture will be converted to substantially nonleachable forms.