Automated crystal optical technique for quantitative determination of phase and particle size composition of alumina

For many years specialists of VAMI have been involved in developing of automated techniques and new equipment arrangement for determination of phase and particle size composition of products in alumina manufacture. Crystal optical analysis being a complicated technique requiring professional background however is not free from subjective estimation as far as the quantitative analysis is concerned. State-of-the art computer diagnostics and processing allow overcoming these problems. Figure 1. Diagram of light refraction Now at several alumina refineries a technique for automated quantitative determination of alumina phase composition using Image Analysis System is tested. This technique is a combination of latest achievements in the instrumentation art, software and many-years practical experience. The following automated techniques were developed with the help of Image Analysis System: 1. determination of alpha-modification content in of all grades alumina irrespectively of method of production of alumina and way of its formation; 2. determination of quantitative phase composition of smelter grade alumina. 3. Automated determination of particle size distribution of aluminium hydroxide containing fine particles. The developed methods solve the problem of phase composition monitoring in the course of phase transformation from hydrargillite to alpha-alumina in the calcination process and control of particle size distribution of aluminium hydroxide in full fraction range.