Development Of Wet Precise Classification Technology For Synthetic Mica Powder

Synthetic mica powder is an important synthetic non-metallic flaky crystal materials with non-fixed diameter, which widely uses in paints, plastics, cosmetics, electronic industry and the other field. The applications need high quality of synthetic mica powder, such as surface finish, size distribution, etc. During the manufacture process of the synthetic mica powder, classification is the main step affecting the production efficiency and quality of product. At present, natural settling classification process was widely used for synthetic mica powder production, which has defects of a large area of equipment, batch production and low degree of automation. Thus, the development of new high-efficiency and high-precision classification equipment is of great significance for improve production efficiency and promote the application of synthetic mica powder.In this study, based on the comprehensive analysis of current particle wet classification technology, the dispersion properties and sedimentation properties of synthetic mica powder in water were studied, then the calculation model was established, and continuous wet precise classification equipment was designed. The equipment configuration and process parameters were optimized based on experimental results, and pilot experiment was carried out. The main works completed include:(1) a suitable dispersion conditions of synthetic mica powder in water were determined, i.e., the concentration of dispersant A is 120 mg/L, pH of the suspension was neutral or alkaline and adjust with NaOH.(2) The interference settling velocity formulas of synthetic mica powder in water were confirmed respectively with the equivalent diameter of Malvern particle size measurement value D99.5, D90, D50.(3) The laboratory equipment was designed, and its configuration and process parameters were optimized based on experimental results, i.e., the inclined plate spacing is 1.0 cm, the angle is 45° and solid holdup of suspension is not more than 20%.(4) The experiment results show that the particle size distribution of products classified by the pilot device meets the product standard, and the processing capability of the pilot device is 6 times higher than the natural sedimentation tank with the same floor space.The developed wet precise classification equipment enables continuous production, the product reach the product standards, and is promising for industrial application.