Abstract: Vacuum thermal reduction technology was used to extract magnesium from ascharite mineral. At the same time, boron in the raw material was kept in residue. The residue could be used as raw materials to make non-alkali glass fiber. Calcined material and residue were analyzed by XRD and compared. Based on thermodynamic analysis, the Gibbs free energy and critical temperature of reduction of ascharite with silicon were calculated. As a result, the critical temperature was 661℃ when the air pressure in the system was 4 Pa. The best calcination conditions were obtained as 1000℃ for 30 min. In addition, the reduction rate of magnesium increased sensibly as long as CaO addition mass was increased.

Key words: ascharite, magnesium, vacuum thermal reduction, thermodynamic analysis, non-alkali glass fiber

摘要： 采用真空热还原法还原硼镁石矿中的镁，并将矿石中的硼保留在还原渣中，使还原渣适用于生产无碱玻璃纤维. 分别对原料和还原渣进行XRD分析和对比，对反应过程进行了热力学计算和分析. 计算得当系统气压为4 Pa时反应温度降为661℃. 确定了硼镁石矿的最佳煅烧条件为1000℃，恒温30 min. 增大CaO加入量镁还原率显著增加.

关键词: 硼镁石矿, 镁, 真空热还原, 热力学分析, 无碱玻璃纤维