Process for the production of stabilized sodium acid pyrophosphate

Claim 1

STABILIZED SODIUM ACID PYROPHOSPHATE OF SUBSTANTIALLY IMPOVED DOUGHNUT BAKING PROPERTIES AND LOW TURBIDITY PRODUCED BY THERMALLY EVAPORATING A MONOSODIUM ORTHOPHOSPHATE SOLUTION CONTAINING FROM 1.0% TO 12.5% BY WEIGHT REFERRED TO NAH2PO4 OF PREVIOUSLY-FORMED SODIUM ACID PYROPHOSPHATE, TOGETHER WITH ABOUT 0.10% TO ABOUT 0.20% K2O AND ABOUT 0.025% TO ABOUT 0.075% AL203, BASIS NAH2PO4, TO PRODUCE SUBSTANTIALLY DRY MONOSODIUM ORTHOPHOSPHATE, CALCINING THE SAID MONOSODIUM ORTHOPHOSPHATE AT A TEMPERATURE OF ABOUT 225* C. TO ABOUT 235* C. UNITL SODIUM ACID PYROPHOSPHATE HAS BEEN FORMED AND THEREAFTER TEMPERING SAID PYROPHOSPHATE BY MAINTAINING IT AT ATMOSPHERIC PRESSURE AND AT A TEMPERATURE OF ABOUT 215* C. TO 245* C. IN AN ATMOPSOHERE CONTAINING 230 MM. TO 760 MM. HG PARTIAL PRESSURE OF STEAM, SAID TEMPERING BEING CARRIED OUT FOR ABOUT ONE HOUR TO ABOUT 4 HOURS.