Abstract: In order to study the solid-phase reduction process of CaW0₄ and Si at low temperature during steelmaking process by direct alloying, the thermo-analysis experiments on CaWO₄ and Si powder mixture have been carried out by using differential thermal analyzer with constant heating rate 10 T/min, the reaction products and reaction ratio of CaWO₂ and Si pellets at 1 400 ℃ for 30 min are analyzed by high temperature furnace constant temperature test and combined with melting point measure test the behavior of physical change of pellets in heating process is analyzed. Experimental results show that the reduction reactions of CaW04 and Si occurred at less than 1 400℃ are all solid-phase reaction, the products of reaction are W, WSi₂, W₅Si₃, Ca₃ ( Si₃0₉ ) and SiO₂, the reduction ratio of CaW0₄ pellets at 1 400 °C for 30 min is up to 93.41% , and during solid-phase reaction process the CaO could not increase the reaction rate； with condition of constant heating rate at less than 1 400℃ , the apparent reaction of CaW0₄ and Si conforms to Avarami -Erofeev equation, the mech-anism of reaction is random nucleation and subsequent growth, and the apparent reaction dynamical equation is da/dt = 11.68e^{-51.75x103/RT.} 4( 1 - a) [ - ln( 1 - a)]^3/4

摘要： 为研究CaWO₄与Si在直接合金化炼钢过程中的低温固相反应过程,采用差示热分析仪在10℃/min恒速升温条件下对CaWO₄与Si粉末混合物进行热分析实验,通过高温炉恒温实验对CaWO₄与Si球团在1400℃恒温30 min的反应生成物及反应率进行分析,结合熔点测试实验分析了球团在升温过程中的物理变化行为。实验结果表明,CaWO₄与Si在1400℃以下所发生的还原反应为全固相反应,反应生成物为W、WSi₂、W₅ Si₃、Ca₃(Si₃O₉) 、SiO₂ 、CaWO₄球团在1400℃   30 min的反应率达到93.41%,固相反应过程中CaO不能促进反应的进行;CaWO₄与Si 1400℃以下恒速升温条件下表观反应符合Avarami-Erofeev方程,反应机理为随机形核和随后生长,表观反应动力学表达式为dα/dt=11.68e^{-51.75x103/RT.} 4(1 - a) [ - ln(1 - a)]^3/4。

关键词: 钨酸钙, 硅还原, 固相反应, 热分析, 动力学