Method for crystallizing a sodium carbonate

Claim 1

A PROCESS FOR PREPARING CARBONATE CRYSTALS SELECTED FROM THE GROUP CONSISTING OF SODIUM SESQUICARBONATE AND SODIUM BICARBONE, FROM AQUEOUS SOLUTIONS CONTAINING CARBONATES SELECTED FROM THE GROUP CONSISTING OF SODIUM BICARBONATE AND MIXTURES OF SODIUM CARBONATE AND SODIUM BICARBONATE, WHICH CRYSTLS ARE IMPROVED IN SIZE, DEWATERING ABILITY AND SETTLING RATE, WHICH COMPRISES ADDING TO SAID AQUEOUS SOLUTIONS PRIOR TO INITIAL CRYSTALLIZATION, UP TO ABOUT 400 PARTS PER MILLION OF AN ANIONIC-ACTIVE SURFACTANT SELECTED FROM THE GROUP CONSISTING OF (1) ALKYL BENZENE SULFONATES CONTAINING AT LEAST 8 CARBON ATOMS IN THE ALKYL CHAIN, (2) ALKYL NAPHTHALENE SULFONATES CONTAINING AT LEAST 4 CARBON ATOMS IN THE ALKYL CHAIN (3) PRIMARY ALKYL ALCOHOL SULFATES CONTAINING AT LEAST 10 CARBON ATOMS AND (4) N-SUBSTITUTED TAURINES OF THE FORMULA R''R'''' NCH2CH2SO3M WHERE R'' IS A HYDROCARBON RADICAL, R" IS THE ACYL RADICAL OF A HIGHER FATTY ACID AND M IS AN ALKALI METAL AND ADDING TO SAID TRONA SOLUTION AN ADDITIONAL AMOUNT OF SULFATE IONS OVER THAT NORMALLY CONTAINED THEREIN TO BRING THE SULFATE ION CONTENT IN SAID SOLUTION TO BETWEEN 0.3% TO 5%, WHEN CALCULATED AS SODIUM SULFATE, CRYSTALLIZING SAID CARBONATE CRYSTALS FROM THE SAID SOLUTION AND SEPARATING SAID CRYSTALS FROM THE MOTHER LIQUOR.