Effect of thermal treatment on magnesite impurity removal using dry high-intensity magnetic separation

Abstract

This study investigates the extraction of impurities from a low-grade Saudi magnesite ore with the following composition: 37.68% MgO, 7.24% CaO, 3.10% SiO₂, 1.91% Fe₂O₃, 0.58% Al₂O₃, and 48.65% LOI. Additionally, it examines the calcination process of magnesite and the subsequent removal of impurities. Dry high-intensity magnetic separation was utilized for the magnesite both before and after calcination. Various parameters, including feed size, feed rate, magnetic field strength, and roll speed, were assessed using an Outotec-induced roll magnetic separator (model MIH 13 111-5). The results demonstrate that impurity removal and recovery are more efficient after calcination than before. The final product is anticipated to be a suitable raw material for producing dead-burned magnesia, which is utilized in the refractory industry.