Novel Alkaline Method for the Preparation of Low-Chromium Magnesia

The typical method for the preparation of chromium-magnesia is by energy-consuming grinding, but the pollution of Cr⁶⁺ ions is a problem. However, the chromium-magnesia refractory is still irreplaceable due to its outstanding performance. In this regard, low-chromium magnesia was prepared by the alkaline chromium precipitation method from cheap light-burned magnesia. The impurities in the light-burned magnesia was removed in order to avoid the formation of Cr⁶⁺. The chromium was precipitated directly on the light-burned magnesia surface without the grinding process. The low-chromium magnesia was obtained after the calcination. The reaction temperature, solid content, reaction time and stirring speed were examined and low-chromium magnesia with Cr³⁺ 0.4%, MgO 98.5% was obtained. The effect of temperature on the surface tomography of low-chromium magnesia was also discussed. The present novel alkaline method should be a promising way for the preparation of low-chromium magnesia.