Manufacture of calcium carbonate

Claim 2

A CONTINUOUS PROCESS FOR PRODUCING CALCIUM CARBONATE COMPRISING THE STEPS OF (1) CONTINUOUSLY MOVING A MIXTURE OF CALCIUM HYDROXIDE AND A FIRST AQUEOUS SOLUTION CONTAINING AN ALKALI METAL CARBONATE THROUGH A REACTION ZONE TO REACT SAID CALCIUM HYDROXIDE WITH NOT MORE THAN 80 WEIGHT PRECENT OF SAID ALKALI METAL CARBONTE TO FORM CALCIUM CARBONATE, (2) CONTINUOUSLY SEPARATING FLUID FROM THE MIXTURE EXITING FROM SAID REACTION ZONE TO FORM A FILTER CAKE, (3) CONTACTING SAID FILTER CAKE WITH A SECOND AQUEOUS SOLUTION CONTAINING ALKALI METAL CARBONATE TO COMPLETE THE CONVERSION OF CALCIUM HYDROXIDE TO CALCIUM CARBONATE AND FORM ALKALI METAL HYDROXIDE, AND REMOVING ALKALI METAL HYDROXIDE FROM SAID CAKKE DURING SAID CONTACTING STEP, AND (4) WASHING THE RESULTING CALCIUM CARBONATE WITH WATER.

Claim 3

IN THE SYSTEM OF PULING LIGNEOUS CELLULOSIC MATERIALS WITH ALKALI METAL BASE COOKING LIQUORS, RECOVERING SPENT COOKING LIQUORS TO FORM GREEN LIQUOR CONTAINING ALKALI METAL CARBONATE IN AQUEOUS SOLUTION, AND CAUSTICIZING SAID GREEN LIQUOR TO CONVERT SAME TO WHITE LIQUOR FOR RECYCLE TO THE PULGING STEP, THAT IMPROVEMENT COMPRISING, MIXING A PORTION OF SAID GREEN LIQUOR WITH CALCIUM HYDROXIDE, CONTINUOUSLY MOVING THE RESULTING MIXTURE THROUGH A REACTION ZONE TO REACT SAID CALCIUM HYDROXIDE WITH NOT MORE THAN 80 WEIGHT PERCENT OF SAID ALKALI METAL CARBONATE CONTAINED BY SAID GREEN LIQUOR TO FORM CALCIUM CARBONTE, CONTINUOUSLY SEPARATING FLUID FROM THE MIXTURE EXITING FROM SAID REACTION ZONE TO FORM A FILER CAKE, AND PASSING ANOTHER PORTION OF SAID GREEN LIQUOR THROUGH SAID FILTER CAKE TO SUBSTANTIALLY COMPLETELY CONVERT THE CALCIUM HYDROXIDE IN SAID CAKE TO CACO3 AND FORM ALKALI METAL HYDROXIDE, ANR REMOVING ALKALI METAL HYDROXIDE FROM SAID CAKE WHILE PASSING SAID PORTION OF GREEN LIQUOD THROUGH SAID CAKE.

Claim 4

IN THE SYSTEM OF PULING LIGNEOUS CELLULOSIC MATERIALS WITH ALKALI METAL BASE COOKING LIQUORS, RECOVERING SPENT COOKING LIQUORS TO FORM GREEN LIQUOR CONTAINING ALKALI METAL CARBONATE IN AQUEOUS SOLUTION, AND CAUSTICIZING SAID GREEN LIQUOR TO CONVERT SAME TO WHITE LIQUOR FOR RECYCLE TO THE PULGING STEP, THAT IMPROVEMENT COMPRISING, MIXING A PORTION OF SAID GREEN LIQUOR WITH CALCIUM HYDROXIDE, CONTINUOUSLY MOVING THE RESULTING MIXTURE THROUGH A REACTION ZONE TO REACT SAID CALCIUM HYDROXIDE WITH NOT MORE THAN 80 WEIGHT PERCENT OF SAID ALKALI METAL CARBONATE CONTAINED BY SAID GREEN LIQUOR TO FORM CALCIUM CARBONTE, CONTINUOUSLY SEPARATING FLUID FROM THE MIXTURE EXITING FROM SAID REACTION ZONE TO FORM A FILER CAKE, AND PASSING ANOTHER PORTION OF SAID GREEN LIQUOR THROUGH SAID FILTER CAKE TO SUBSTANTIALLY COMPLETELY CONVERT THE CALCIUM HYDROXIDE IN SAID CAKE TO CACO3 AND FORM ALKALI METAL HYDROXIDE, ANR REMOVING ALKALI METAL HYDROXIDE FROM SAID CAKE WHILE PASSING SAID PORTION OF GREEN LIQUOD THROUGH SAID CAKE.