Effect of precipitation inhibitors on calcium phosphate scale formation

Abstract

The highly reproducible pH-stat technique was used to study the influence of various types of inhibitors on the precipitation of calcium phosphate from solution. Three types of inhibitors were evaluated: (1) homo- and copolymers of acrylic acid, (2) polyphosphate and phosphonates, and (3) polycarboxylic acids. Experimental variables studied included pH, temperature, and inhibitor dosage all of which were found to greatly affect the precipitation of calcium phosphate. The role of polyacrylic acid molecular weight is addressed. Comparative data for the various types of inhibitors is discussed. Keywords: precipitation inhibitors, calcium phosphate scale formation.