Performance assessment of various polymer flocculant types in clay-dolomite flocculation of tincal ore using macroscopic metrics

Borax, an important, refined boron product, is obtained by processing tincal ore through dissolution, separation from clay, crystallization, dewatering, and drying processes in factories. Precipitation of suspended clays with flocculant is a crucial stage in the process. In this study, suitable flocculant properties and appropriate operating conditions were determined in a laboratory setting for the refined borax production process. The studies were conducted using samples taken directly from the process and under the process conditions (95 °C, pH = 9.5). Flocculants with different properties (anionic, cationic, nonionic), obtained from a commercial firm, were used. The effect of flocculant type, charge density, and molecular weight on supernatant turbidity and solid settling rate was investigated as a function of flocculant dose, mixing rate and duration. All flocculants showed a parabolic trend with minimum turbidity and maximum settling rate. Anionic flocculants provided significantly higher flocculation efficiency. The anionic flocculant (AH3), with high molecular weight and low charge, demonstrated the highest flocculation performance, resulting in a turbidity of 9 NTU and a settling rate of 67 mm/min. The optimum flocculant dosage, mixing rate, and time for all flocculants were determined to be 2 mg/L, 150 rpm, and 1 min, respectively.