关键词: 老卤, 氧化镁, 流态化

Abstract: The soda method is mainly used in the domestic high-purity magnesia production industry because of its operational simplicity. However,the excessively high production cost is an obvious shortcoming. In this paper,various technologies of producing high purity magnesia from brine,which is the by-product in the processes of the sea salt chemical industry and the potassium chloride production from salt lake carnallite resources,are systematically summarized,and the advantages and the disadvantages of each technology are analyzed. The slaked lime or dolomite precipitation method,which has been developed into a practical,low cost process and been universally adopted by the major international high purity magnesia producers,the ammonium method which is still developing,the soda method which is easy but high-cost,and the ammonium bicarbonate method are introduced,in that order. The pyrohydrolysis method including its technological principle,the famous Aman process,and its research progress in China is described. Moreover,the fluidized pyrohydrolysis process of lowly hydrated magnesium chloride as the lasting technology of high-purity magnesia and industrial concentrated hydrochloric acid co-production is firmly recommended. Due to its significant superiority in low cost and ability to improve the production capacity of enterprises,this innovative fluidized pyrohydrolysis process may become an ideal alternative method of the high purity magnesia production,replacing the traditional soda method.

Key words: brines, magnesia, fluidization