Selective carbonation of slurries and mixtures of calcium and magnesium hydroxide

Claim 1

IN THE MANUFACTURE OF HIGHLY CONCENTRATED MAGNESIUM BICARBONATE SOLUTION FROM A SLURRY COMPOSED PRIMARILY OF A MIXTURE OF MAGNESIUM AND CALCIUM HYDROXIDES FORMED FROM THE SUBSTANTIALLY COMPLETE CALCINATION OF DOLIMITE, A CONTINUOUS SEQUENCE OF CARBONATION STEPS IN A SERIES OF ZONES INCLUDING THE STEPS OF CARBONATING TO CALCIUM CARBONATE SUBSTANTIALLY ONLY THE CALCIUM HYDROXIDE OF THE SLURRY IN THE FIRST OF SAID ZONES, PASSING THE PARTIALLY CARBONATED SLURRY TO THE SECOND OF SAID ZONES, COOLING AND DILUTING THE PARTIALLY CARBONATED SLURRY BY MIXING THEREWITH AQUEOUS TAILINGS CONTAINING MAGNESIUM SALTS AND CARBON DIOXIDE, GRADULLY CARBONATING THE SLURRY BEING PASSED THROUGH SAID SECOND ZONE WITH A GAS CONTAINING FROM 8 TO 50% OF CARBON DIOXIDE, THEREBY MINIMIZING THE FORMATION OF NORMAL MAGNESIUM CARBONATE, CONTINUOUSLY PASSING THE GRADUALLY CARBONATED SLURRY INTO A THIRD ZONE, CARBONATING THE SLURRY WITH SUBSTANTIALLY PURE CARBON DIOXIDE TO FROM A HIGHLY CONCENTRATED MAGNESIUM BICARBONATE SOLUTION, SEPARATING THE SLUDGE OF CALCIUM CARBONATE FROM THE MAGNESIUM BICARBONATE SOLUTION WHILE MAINTAINING SAID SO-