PREPARATION OF CHROME YELLOW AND MOLYBDATE ORANGE PIGMENTS

摘要

O.Z. 0050/41591 Chrome yellow/molybdate orange pigments are prepared with reuse of the nitric acid and sodium hydroxide by electrochemically splitting the sodium nitrate solution obtained in the pigment synthesis into sodium hydroxide and nitric acid in a three-divided electrolysis cell where the central compartment, which contains the sodium nitrate, is separated from the cathode space by a cation exchange membrane and from the anode space by an anion exchange membrane, and using the nitric acid for preparing lead nitrate from lead oxide and the sodium hydroxide for making sodium aluminate from aluminum hydroxide and for setting the pH.