METHOD OF TREATING ALKALI METAL SULFIDE AND CARBONATE MIXTURES

摘要

METHOD OF TREATING ALKALI METAL SULFIDE AND CARBONATE MIXTURES Arthur L. Kohl Robert D. Rennick Martin W. Savinsky A method of removing and preferably recovering sulfur values from an alkali metal sulfide and carbonate mixture comprising the steps of (1) introducing the mixture in an aqueous medium into a first carbonation zone and reacting the mixture with a gas containing a major amount of CO2 and a minor amount of H2S; (2) introducing the resultant product from step 1 into a stripping zone maintained at subatmospheric pressure, and contacting this product with steam to produce a gaseous mixture, comprising H2S and water vapor, and a liquor of reduced sulfide content; (3) introducing the liquor of reduced sulfide content into a second carbonation zone, and reacting the liquor with substantially pure gaseous CO2 in an amount sufficient to precipitate bicarbonate crystals and produce an offgas containing CO2 and H2S for use in step 1; (4) recovering the bicarbonate crystals from step 3, and thermally decomposing the crystals to produce an alkaline metal carbonate product and a substantially pure CO2 offgas for use in step 3.