Study of the process of purifying potassium humate suspension from suspended particles using industrial centrifuges

Abstract

Potassium humate suspensions obtained by alkaline extraction of peat using cavitation dispersion contain suspended solid particles that require effective separation to improve product quality. The separation of suspended solid particles larger than 20 μm is particularly important to ensure product purity. The main objectives of the study were to determine the possibility of removing suspended solid particles from potassium humate suspension and to evaluate the efficiency of the separation process on a laboratory and industrial scale. Laboratory tests included sedimentation under the action of Earth's gravity for two months, centrifugation in a laboratory cup centrifuge at different speeds, and analysis of solid content, particle size distribution, pH, and conditional viscosity. Industrial tests were carried out on an Ecomash SHS 311 centrifuge in both batch and continuous modes at different rotor speeds and flow rates. The purified product (fuga) was analysed by sieving through 20 and 40 μm sieves and measuring viscosity. Laboratory sedimentation showed the formation of a compact sediment layer, confirming the presence of suspended solids. Industrial tests demonstrated effective removal of suspended solids at a separation factor (Fr) ≥ 1550, with no visually detectable particles larger than 20 μm in the filtrate. Viscosity measurements correlated well with suspended solids content and were proposed as a rapid control method. Centrifugation effectively removes suspended solids from potassium humate suspensions in both laboratory and industrial conditions. The separation factor significantly affects the efficiency of purification. For operational quality control, sieving in combination with viscosity measurement is recommended. Further laboratory studies are needed to establish the dependence of viscosity on solids content and temperature to improve process control.