Abstract: Inhibition properties of organophosphonic acids and copolymers on calcium carbonate and phosphate scale were studied.Experimental results indicated that scale inhibition percentages of 1-hydroxyethylidene diphosphonic acid(HEDP) on calcium carbonate did not increase with the increasing concentrations of HEDP;for copolymers AA/AMPS and AA/AMPS/MMA,there existed critical concentrations for inhibiting calcium phosphate scale;AA/HPA(or AA/AMPS) and orthophosphate had synergistic effects for inhibiting calcium carbonate scale within certain concentration ranges.These conclusions may have directive value on the practical use of organophosphonic acids and copolymers.

Key words: organophosphonic acid, copolymer, scale inhibitor, synergistic effect