MAGNESIUM HYDROXIDE RECOVERY FROM MAGNESIA WASTE BY CALCINATIONS AND HYDRATION PROCESSES

Abstract

In this study, hydration behavior of the magnesia waste, supplied from the electrostatic bag house of the sintering unit of MAS Company, Eskisehir-Turkey was studied to find out re-usability of the material as a source of magnesium hydroxide (Mg(OH)(2)) production. According to chemical and crystalline phase analyses, MgO content of the sample was determined as 49.9 wt% and consists of mainly raw magnesite (MgCO3), sintered magnesia-periclase (MgO) and small amount of serpentine (lizardite) phases. In hydration process, the reactivity of magnesium oxide determines the rate and extent of hydration of the sample. Therefore, the waste samples both calcined and uncalcined forms were hydrated in water and the efficiencies were compared according to sample source. The hydration experiments were carried out at temperatures ranging from 30 degrees C and 80 degrees C to evaluate the influence of temperature on particle morphology and surface areas of the products. The efficiency of the hydration was evaluated by using thermogravimetric (TG) and scanning electron microscopy (SEM) analyses. The test results suggest that the magnesia waste could be used as a source material for production of magnesium hydroxide.