Recovery of phthalocyanine coloring maters

Claim 1

IN THE UREA-PROCESS OF PREPARING A COPPERPHTHALOCYANINE, WHEREIN PHTHALOCYANINE-FORMING ORGANIC INTERMEDIATES ARE REACTED WITH COPPER YIELDING AGENTS IN THE PRESENCE OF UREA AND AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF TRICHLOROBENZENE AND KEROSENE, THE IMPROVEMENT WHICH CONSISTS OF ISOLATING THE PRODUCED PIGMENT BY AGITATING THE ENTIRE REACTION MASS WITH SULFURIC ACID OF 85 TO 100% STRENGTH, IN QUANTITY CALCULATED TO SUPPLY NOT LESS THAN 1.0 AND NOT MORE THAN 1.5 PARTS BY WEIGHT OF H2SO4 FOR EACH PART OF PIGMENT PRODUCED, AND AT A TEMPERATURE BETWEEN 90* AND 150* C., WHEREBY TO CONVERT THE PIGMENT INTO ITS TETRASULFATE IN SOLID FORM AND SIMULTANEOUSLY TO CONVERT THE BYPRODUCTS OF THE REACTION MASS INTO A FORM SOLUBLE IN DILUTE ACID, THEN SEPARATING THE BULK OF THE LIQUID PHASE AND TREATING THE RESIDUAL MASS WITH WATER, WHEREBY TO LIBERATE THE PIGMENT IN SOLID FORM FROM ITS TETRASULFATE WHILE DISSOLVING THE CONVERTED IMPURITIES, ENABLING SEPARATION BETWEEN THE TWO.