Synthesis of sodium polyacrylate copolymers as water-based dispersants for ultrafine grinding of praseodymium zirconium silicate A Physicochemical and engineering aspects

A series of sodium polyacrylate copolymers (i.e., poly acrylic acid-co-itaconic acid-co-2-acrylamide-2-methylpropanesulfonic acid or PSIA with different molecular weights and monomer molar ratios) were synthesized based on acrylic acid-co-itaconic acid (PAI) as water-based dispersants for ultrafine grinding of praseodymium-doped zirconium silicate (Pr-ZrSiO4). The particle size/size distribution, suspension rheology and dispersant adsorption were analyzed by laser particle size analysis, rheometry, Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG) and electrokinetic potential measurement, respectively. Compared to the dispersant PAI, the use of the dispersant PSIA1 with a greater molecular weight in the Pr-ZrSiO4 suspension ground for 45 min at pH values 7.0–8.0 can give a finer product with the narrower particle size distribution. The dispersant PSIA1 used in ultrafine grinding has a suitable viscosity of the suspension and generates more hydrogen bonds on the particle surface, and sulfonic acid group in the dispersant PSIA1 can provide a greater charge density than carboxylic acid groups in the dispersant PAI. In addition, the total potential energies between the particles in suspension with different copolymer dispersants at different pH values were also calculated. It is indicated that the effective ultrafine grinding of the particles is related to the total interparticle potential energy provided by the dispersant PSIA1 at pH 7.0–8.0.