Patent ID: 7897126

Claim:
A process for extracting and recovering alkali metal from a char, the char comprising (i) one or more soluble alkali metal compounds and (ii) insoluble matter comprising one or more insoluble alkali metal compounds, the process comprising the steps of: (a) providing char at an elevated temperature ranging from 50° C. to about 600° C.; (b) quenching the char in an aqueous medium to fracture the char and form a quenched char slurry; (c) contacting the quenched char slurry with carbon dioxide under suitable pressure and temperature so as to convert at least a portion of the insoluble alkali metal compounds to one or more soluble alkali metal compounds, and produce a leached slurry comprising the soluble alkali metal compounds and residual insoluble matter; (d) degassing the leached slurry under suitable pressure and temperature so as to remove a substantial portion of the excess carbon dioxide and hydrogen sulfide, if present, and produce a degassed leached slurry; (e) separating the degassed leached slurry into a liquid stream and a residual insoluble matter stream, the liquid stream comprising a predominant portion of the soluble alkali metal compounds from the degassed leached slurry, and the residual insoluble matter stream comprising residual soluble alkali metal compounds and residual insoluble alkali metal compounds; (f) recovering the liquid stream; and (g) washing the extracted insoluble matter stream with an aqueous medium to produce a wash stream comprising substantially all of the residual soluble alkali metal compounds from the residual insoluble matter stream, wherein the quenching and contacting is performed in the substantial absence of gaseous oxygen.