Recovery of alkali values from trona ore

A method of recovering alkali values from a subterranean trona deposit which comprises

• (i) introducing into the region of the trona deposit an aqueous mining solvent containing from about 3 to about 8% sodium sulfide;
• (ii) maintaining the solvent in the region to solubilize at least a portion of the trona as sodium carbonate whereby sodium sulfide is converted into sodium hydrosulfide;
• (iii) withdrawing from the region at least a portion of the resulting mining solution containing sodium carbonate and sodium hydrosulfide;
• (iv) treating the withdrawn mining solution with hydrogen sulfide to convert the major portion of the sodium carbonate into a sodium salt selected from the group sodium sesquicarbonate, sodium bicarbonate and mixtures thereof, the salt or mixtures thereof being precipitated and whereby the hydrogen sulfide is converted into sodium hydrosulfide;
• (v) separating the precipitated sodium salt from the mother liquor containing sodium hydrosulfide;
• (vi) subjecting the mother liquor to distillation whereby the sodium hydrosulfide is converted into hydrogen sulfide and sodium sulfide which remains dissolved in mother liquor;
• (vii) recycling the hydrogen sulfide to step (iv);
• (viii) adding water and sodium sulfide to the mother liquor obtained in step (vi) to reconstitute the mining solvent;
• and
• (ix) recycling the reconstituted mining solvent to step (i) and repeating the cycle of recovery.