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采用物料失重率、金属Mg还原率、X射线衍射(XRD)与扫描电子显微镜(SEM)等手段与方法,研究了真空条件下氧化镁碳热还原温度、物料造球成型压力、物料配比、碳热还原保温时间以及催化剂对氧化镁碳热还原法炼镁工艺的影响。研究结果表明,在30~100 Pa时,碳热还原温度高于1553 K,控制物料压块压力为8 MPa,此时物料失重率最大,最有利于氧化镁的还原。随着焦煤还原剂与氧化镁摩尔比以及碳热还原时间的增加,碳热还原反应速率加大,还原率提高,但是变化效果不明显,加入氟盐CaF2后,物料失重率明显提高,添加CaF2的质量超过物料总质量的3%时,物料失重率超过95%,还原率也相应大幅提高。因此,选择适当的焦煤还原剂与氧化镁摩尔比值以及碳热还原时间,添加超过3%CaF2,将有利于该法炼镁过程的顺利进行与金属Mg还原率的提高。此研究为真空碳热法从氧化镁中提取金属Mg工艺提供了很好的实验依据。
The weight loss rate of metal, metal Mg reduction rate, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study the effect of the carbothermal reduction temperature of magnesia, the forming pressure of the material ball, the material ratio, Effect of Carbothermal Reduction Preheating Time and Catalyst on Magnesium Smelting by Magnesite Reduction by Magnesia. The results show that the carbothermal reduction temperature is higher than 1553 K at 30 ~ 100 Pa and the pressure of the briquetting material is controlled at 8 MPa. At this time, the weight loss rate of the material is the largest, which is most favorable for the reduction of magnesium oxide. With the increase of molar ratio of coking coal reducing agent to magnesium oxide and carbothermal reduction time, the rate of carbothermal reduction reaction increased and the reduction rate increased, but the effect was not obvious. After the addition of fluoride salt CaF2, the weight loss rate of CaF2 increased obviously. The quality of more than 3% of the total mass of the material, the material weight loss rate of more than 95%, the reduction rate also increased significantly. Therefore, choosing the appropriate molar ratio of coking coal reducing agent to magnesium oxide and the carbon thermal reduction time, the addition of more than 3% CaF2 will be beneficial to the smoothing of the magnesium refining process and the improvement of the metal Mg reduction rate. This study provides a good experimental basis for the vacuum carbothermal extraction of magnesium from magnesium metal process.