Patent ID: 6319358
Filing Date: 2001-11-20
Classification: D21C

Abstract:
A method for electrolytically treating molten Kraft smelt to provide sodium sulfide to a Kraft process, the molten Kraft smelt comprising sodium sulfide, sodium sulfate, sodium chloride and alkali metal carbonates, the method comprising:providing an electrolytic cell having an anode and a cathode;feeding the molten Kraft smelt into the cell, wherein the molten Kraft smelt comprises sodium carbonate, potassium carbonate, sodium sulfide, sodium sulfate and sodium chloride, the molten Kraft smelt having a temperature of from about 750.degree. C. to about 950.degree. C.; andapplying an electrical potential which is effective for preventing reactions of sulfide in the molten Kraft smelt, the potential between the anode and the cathode with the molten Kraft smelt therebetween in an environment that is substantially without liquid water,whereby the method is effective for providing sodium sulfide to a Kraft process and at least about 75% of the alkali metal carbonates in the molten Kraft smelt are converted to alkali metal oxides or alkali metal hydroxides.