The inhibition of calcium sulfate and barium sulfate nucleation in NaCl brines by phosphonates and polycarboxylates was studied at 25°C, 50°C, 70°C, and 90°C in terms of the prolonged induction period. Hexamethylenediaminetetra(methylene phosphonic) acid (HDTMP) was found to be an effective inhibitor for the scaling of calcium sulfate. 1-hydroxyethylene-1, 1-diphosphonic acid (HEDP) and phosphinopolycarboxylic acid (PPPC) were found to be effective inhibitors for BaSO4 scaling. The inhibition of nucleation through prolongation of the nucleation induction period resulted from an increase in the interfacial tension between the crystal and aqueous solution due to the presence of the inhibitors. It was observed that the inhibition of nucleation depends highly on the lattice cation/anion molar ratio and the pH of the solution as well as the supersaturation and temperature for a given inhibitor.

Subject
Acids, Water, Inhibitor performance, Barium sulfate, Scale inhibitors, Nucleation, Interfacial tension, Gypsum, Sodium chloride solution, Chemical inhibition, Saturation index, Calcium sulfate, Corrosion inhibitors
Keywords:
calcium sulfate, barium sulfate, nucléation kinetics, scale, inhibitors
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1994
Association for Materials Protection and Performance (AMPP)
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