THE INFLUENCE OF SODIUM CARBOXYMETHYL CELLULOSE ON THE SEDIMENTATION BEHAVIOUR OF NICKEL PHOSPHATE PRECIPITATE AT VARYING TEMPERATURES

Abstract

The sedimentation data of nickel phosphate precipitate formed with or without a modifier - sodium carboxymethyl cellulose (Na-CMC) biopolymer were studied under controlled conditions of temperature. The main objective was to access the influence of Na-CMC and temperature on On-set Sedimentation Rate (OSR) and Sedimentation Volume Ratio (SVR) of nickel phosphate. Na-CMC at different concentrations (200ppm - 2000ppm) was mixed with constant volume of disodium hydrogen phosphate solution in a graduating measuring cylinder. On mixing the resulting solution with constant volume of nickel chloride solution, a precipitate was formed, stirred for 1 min and placed in the sedimentation measurement device - PreSed Meter. The settling of the precipitate was monitored and recorded at different temperatures (30oC, 40oC and 50oC). Blank sedimentation (0ppm Na-CMC) was also run at various temperatures by adding 10ml of deionized water (instead of 10ml of Na-CMC solution). A plot of precipitate displacement per settling time established a logarithmic curve which flattened with time. Regression analyses of OSR (0.71 ≤ R2 ≥ 0.94) and SVR (0.51 ≤ R2 ≥ 0.93) indicated the dependence of sedimentation on concentration of Na-CMC thus implying chemical interaction between the chemical species.