PROCESS FOR REDUCING THE PERCENTAGE OF DIAMETER ALUMINA TRIHYDRATE CRYSTALS LESS THAN 200 MICRONS OBTAINED FROM THE BAYER METHOD LIQUEURS AND METHOD FOR EXTRACTING SODIUM OXALATE CRYSTALS FROM THE SAME

摘要

P THIS PROCESS REDUCES THE PERCENTAGE OF DIAMETER ALUMINA TRIHYDRATE CRYSTALS LESS THAN 200MICRONS, WHICH CRYSTALS ARE PRODUCED DURING THE CRYSTALLIZATION OF ALUMINUM TRIHYDRATE FROM FRESH BAYER LIQUIDS CONTAMINATED WITH SODIUM OXALATE. / P P FOLLOWING THE INVENTION, ADDED TO THE FRESHLY LIQUEURS OF THE BAYER PROCESS, AFTER SEPARATION OF THE RED SLUDGE AND IMMEDIATELY BEFORE CRYSTALLIZING THE ALUMINA TRIHYDRATE, AN EFFECTIVE QUANTITY OF A POLYACRYLIC ACID BY WEIGHT HIGH MOLECULAR HAVING A MEDIUM MOLECULAR WEIGHT OF NOT LESS THAN ONE MILLION AND CONTAINING AT LEAST 50M PERCENT PER MONOMER OF ACRYLIC ACID. / P P THE INVENTION FINDS AN ADVANTAGEOUS APPLICATION OR ON THE FRESH LIQUORS OR ON THE EXTENDED LIQUEURS OF THE BAYER PROCESS. / P