Bischofite Preparation Process Of The High-quality Magnesium Carbonate

Based on the comprehensive development of the resources in the salt lakes spreaded in the Qinghai Province, in the research of this dissertation a high-tech and high added value approach is proposed to utilize magnesium chloride resource. Basic magnesium carbonate is obtained by the method of chemical precipitation and pyrogenation, which uses bischofite in the salt lakes as the material and ammonium bicarbonate as the precipitant. The optimum process parameters to produce basic magnesium carbonate are studied here. This study will provide an effective path of developing the magnesium resource in Qinghai area comprehensively.The main research contents list as the following:(1) The optimum process parameters of obtaining magnesium carbonate with bischofite in the salt lakes and ammonium carbonate by chemical precipitation method are studied here. The main parameters in the chemical precipitation reaction such as concentration of Mg2+, raw material ratio, reaction temperature, reaction duration and pyrogenation duration that influence the content of magnesia in the product are investigated by orthogonal experiment. The influence of ammonia to the content of magnesia in the product is investigated by single parameter experiment. (2) The optimum process parameters of obtaining basic magnesium carbonate with self-made magnesium carbonate by pyrogenation method are studied here. The main parameters in the pyrogenation reaction such as pyrogenation temperature, pyrogenation duration, raw material mass ratio and agitation speed that influence the content of magnesia in the product are investigated by orthogonal experiment.(3) Analyzed by X-ray diffraction, the structure of product basic magnesium carbonate is confirmed to be monocline crystal of 4MgCO₃·Mg(OH)₂·4H₂O. The purity of the product basic magnesium carbonate is comparatively high, the content of magnesia is above 41%.