CaSO_4与CaS在N_2气氛下反应动力学

Kinetics of reaction between CaS and CaSO_4 under N_2 atmosphere

利用热重分析仪研究了不同摩尔比下的硫酸钙和硫化钙混合物在N2气氛下的反应特性,探讨了其化学反应动力学及反应机理.CaSO4和CaS的固固反应是CaS氧化生成CaO反应的速率控制反应.当CaSO4过量时,CaSO4与CaS的反应分两个阶段.在890～1120℃温度范围内CaSO4与CaS发生固固反应.在1160～1330℃温度范围内,剩余的CaSO4发生自身分解.当CaSO4与CaS的摩尔比为3∶1时,反应的活化能最大.CaSO4和CaS的反应机理可以采用液态共熔体模型来解释.

The reaction between CaS and CaSO4 with different molar ratios in N2 atmosphere was investigated with a Metteler Toledo thermogravimetric analyzer. In this work, the chemical reaction kinetics and mechanism were discussed in detail. The reaction between CaS and CaSO4 was the ratecontrolling step in the oxidation of CaS to CaO. When CaSO4 was in excess, the reaction proceeds in two steps. The apparent solid-solid reaction between CaS and CaSO4 started at 890℃ and ended at 1120℃.Then the residual CaSO4 continued decomposing in the range of 1160-1330℃. When the molar ratio of CaSO4 to CaS was 3, the maximal activation energy of 302.46 kJ · mol^-1 was obtained. The reaction mechanism could be explained by a eutectic liquid model.