新型碳还原炼镁工艺热力学分析及可行性研究

Thermodynamic Analysis and Feasibility Study of a Novel Carbothermal Reduction of Magnesium Smelting

碳热法炼镁工艺具有能耗低和碳排放低的优点,但由于混合气发生逆反应的问题导致其并未工业化应用。提出一种新型碳还原炼镁工艺,并运用热力学计算软件FactSage8.2进行热力学分析。第一阶段炼镁工艺的合适温度和系统真空度区间分别为1250~1350℃和2000~4000 Pa;第二阶段电石冶炼工艺的合适温度和系统真空度区间分别为1650~1800℃和3000~10000 Pa。相关试验结果表明:随着系统压强的增大,第一阶段副反应发生程度减弱;在1350℃、4000 Pa和反应时间2 h的条件下,第一阶段炼镁还原率达90%以上且副反应发生程度微弱;在1800℃、5000 Pa和反应时间0.5 h的条件下,第二阶段反应所得电石品质可达到市场优等品(发气量≥300 L/kg)的标准。

The carbothermal process of magnesium smelting has the advantages of low energy consumption and low carbon emissions.However,it has not been used industrially due to the problem of reverse reaction in the mixed gas.A new type of carbothermal reduction of magnesium smelting was proposed and thermodynamic calculation was carried out by FactSage8.2 software.The suitable temperature and system vacuum degree for the first stage magnesium refining process are 1250—1350℃ and 2000—4000 Pa,respectively,while for the second stage carbothermic smelting process they are 1650—1800℃ and 3000—10000 Pa,respectively.The experimental results show that with the increase of system pressure,the degree of occurrence of side reactions in the first stage decreases.Under the conditions of 1350℃,4000 Pa and a reaction time of two hours,the reduction rate of magnesium refining in the first stage is over 90% and the occurrence of secondary reactions is weak.Under the conditions of 1800℃,5000 Pa and a reaction time of half hour,the quality of calcium carbide obtained in the second stage reaction can meet market standards for superior grade(gas yield≥300 L/kg).