Dense sodium carbonate process

Claim 1

A CYCLIC METHOD OF FORMING DENSE SODA ASH WHICH COMPRISES MIXING CRUDE SODIUM BICARBONATE WITH RECYCLED MOTHER LIQUOR TO PRODUCE A CRUDE SODIUM BICARBONATE SLURRY, PASSING SAID SLURRY INTO A CLOSED DECOMPOSITION VESSEL WHEREIN SAID SLURRY IS HEATED TO A TEMPERATURE OF ABOUT 100*C. TO ABOUT 250*C. AND AT SUPERATMOSPHERIC PRESSURE, CONTINUING SAID HEATING UNTIL THE SODIUM BICARBONATE IS DECOMPOSED TO A MINIMUM OF ABOUT 20 MOL PERCENT TO PRODUCE A PARTIALLY DECOMPOSED SODIUM BICARBONATE SLURRY AND DECOMPOSITION GASES, REMOVING SAID DECOMPOSITION GASES FROM THE DECOMPOSER AND PASSING SAID PARTIALLY DECOMPOSED SLURRY INTO A PRESSURE VESSEL AND HEATING SAID SLURRY THEREIN TO A TEMPERATURE OF ABOUT 150*C. TO ABOUT 250*C. AT A PRESSURE FROM ABOUT 80 P.S.I.A. TO ABOUT 500 P.S.I.A., CONTINUING SAID HEATING UNTIL A MINIMUM OF 55 MOL PERCENT OF THE SODIUM BICARBONATE HAD BEEN DECOMPOSED TO PRODUCE DECOMPOSITION GASES AND A MIXTURE OF ANHYDROUS SODIUM CARBONATE CRYSTALS AND MOTHER LIQUOR, REMOVING SAID DECOMPOSITION GASES FROM THE DECOMPOSITION VESSEL AND SEPARATING THE ANHYDROUS SODIUM CARBONATE FROM THE MOTHER LIQUOR AT A TEMPERATURE ABOVE THE TRANSITION TEMPERATURE OF MONOHYDRATED SODIUM CARBONATE TO ANHYDROUS SODIUM CARBONATE, RECYCLING THE MOTHER LIQUOR AND MIXING IT WITH ADDITIONAL CRUDE SODIUM BICARBONATE.