Baseline performance evaluation of micronized-magnetite recovery using conventional wet-drum and high-gradient magnetic separators

摘要

In 1990 and 1991, a series of 97 laboratory-scale conventional wet-drum magnetic separation tests and 52 high-gradient magnetic separation tests were carried out at the Pittsburgh Energy Technology Center (PETC) of the US Department of Energy to investigate the performance of these processes in separating micronized magnetite ((minus)10 mu m) from fine coal ((minus)600 mu m). This testing was part of a multiyear investigation into the evaluation and development of PETC's Micro-Mag Process, which involves the use of a micronized-magnetite and water mixture for cleaning fine coal in a cyclone, along with the subsequent recovery and reuse of the micronized magnetite. Some of the process variables studied included magnetite particle size, feed percent solids, magnetite-to-coal ratio, feed rate, and staging. The performance was analyzed in terms of magnetite recoveries and corresponding purities. The results demonstrated that recoveries of nearly 91% with purities of about 9% magnetite were possible using a multistage (3 stages) conventional wet-drum recovery circuit. Under some conditions, recoveries approaching 99.9% with purities of nearly 95% were possible in a single pass through a high-gradient magnetic separator. This report provides the detailed operating and performance data for these series of tests. (ERA citation 17:027198)