Process for producing magnesium hydroxide

Claim 1

IN A PROCESS FOR PRODUCING MAGNESIUM HYDROXIDE WHICH COMPRISES THE STEPS OF INTRODUCING DILUTE MAGNESIUM SALT-CONTAINIG BRINE TO A REACTION SYSTEM, ADDING CALCINED DOLOMITE OF PARTICLE SIZE NOT LESS THAN THAT RETAINED ON 200 MESH SCREEN TO SAID DILUTE BRINE, AGITATING THE MIXTURE IN A REACTION ZONE, WITHDRAWNG FROM SAID AGITATED MIXTURE AS UNDERFLOW A SLUDGE ENRICHED IN IMPURITIES, WITHDRAWING FROM SAID MIXTURE AS OVERFLOW REACTED BRINE CONTAINING A SUSPENSION OF MAGNESIUM HYDROXIDE CRYSTALS, AND FLOWING SAID REACTED BRINE TO A THICKENING ZONE, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF RECYCLING TO THE REACTION SYSTEM A PORTION OF SAID REACTED BRINE IN AMOUNT OF FROM ABOUT ONE-HALF TO ABOUT TWO TIMES THE VOLUME OF UNREACTED BRINE BEING INTRODUCED TO THE REACTION SYSTEM, AND ADDING ADDITIONAL MAGNESIUM HYDROXIDE CRYSTALS TO THE REACTION SYSTEM IN AMOUNT SUFFICIENT TO PROVIDE IN THE REACTION ZONE A TOTAL MAGNESIUM HYDROXIDE CRYSTAL CONTENT IN PROPORTION OF FROM ABOUT 3 TO ABOUT 15 TIMES THE WEIGHT OF MAGNESIUM HYDROXIDE BEING PRODUCED.