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

摘要： 纯碱法具有工艺简单的技术优点，被国内高纯氧化镁生产企业普遍采用，但是它存在生产成本较高的显著缺点。本文系统地综述了目前工业上利用海盐化工、盐湖提钾等过程副产的老卤液生产高纯氧化镁的各种技术，分析了每种生产技术的优缺点。依次介绍了技术成熟、生产成本低、被国际主要的高纯氧化镁生产企业广泛采用的白云石/石灰石法，技术有待改进的氨法，工艺简单、成本较高的纯碱法，以及碳铵法。特别地，详细阐述了直接热解法的技术基础、Aman法热解工艺以及国内对直接热解法工艺的研究进展。重点推介了低水合氯化镁流态化热解生产高纯氧化镁、同时联产工业浓盐酸的最新技术。指出流态化热解技术可能是我国高纯氧化镁产业降低生产成本、提高企业产能、能够取代传统纯碱法的理想工艺路线。

关键词: 老卤, 氧化镁, 流态化