Processes of regenerating chemical nickel plating solutions

Claim 1

THE PROCESS OF REGENERATING A DEPLETED AQUEOUS CHEMICAL NICKEL PLATING SOLUTION CONTAINING DESIRABLE NICKEL CATIONS AND HYPOPHOSPHITE ANIONS AND UNDESIRABLE PHOSPHITE ANIONS AND HAVING A PH BELOW ABOUT 5.5, COMPRISING ADDING TO THE DEPLETED PLATING SOLUTION BOTH AN ALKALINE EARTH HYDROXIDE AND AN ALKALINE EARTH SALT OF A MINERAL ACID, SAID ADDITION SUPPLYING SUFFICIENT HYDROXYL IONS TO THE RESULTING SOLUTION TO INCREASE THE PH THEREOF INTO THE RANGE 5.5, TO 7.0, BUT NOT ABOVE, SO AS TO PRECIPITATE THEREIN ALKALINE EARTH PHOSPHITE, WITHOUT PRECIPITATING THEREIN ANY SUBSTANTIAL AMOUNTS OF ALKALINE EARTH HYPOPHOSPHITE OR OF ANY NICKEL COMPOUND, SAID ADDITION SUPPLYING SUFFICIENT ALKALINE EARTH CATIONS TO THE RESULTING SOLUTION TO EFFECT THE REMOVAL THEREFROM OF A SUBSTANTIAL PROPORTION OF THE PHOSPHITE ANIONS THEREIN, REMOVING THE PRECIPITATED ALKALINE EARTH PHOSPHITE FROM THE RESULTING SOLUTION, AND THEN ADDING TO THE RESULTING SOLUTION THE REQUIRED NICKEL CATIONS AND HYPOPHOSPHITE ANIONS AND HYDROGEN IONS TO PRODUCE A PLATING SOLUTION OF DESIRED COMPOSITION.