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针对硫精矿中硫的脱除问题,研究了低品位硫精矿在富氧条件下焙烧反应的动力学过程。利用XRD、SEM和EDS分析了硫精矿氧化焙烧过程的矿相变化规律。同时,根据其热分析的DSC和TG曲线,采用AcharBrindley-Sharp-Wendworth微分法和Coats-Redfern积分法分别计算了脱硫反应的动力学参数,确定了硫精矿不同温度段脱硫的反应机制。结果表明:随着温度的升高,复杂的硫精矿逐渐被氧化成赤铁矿,其中伴随着中间产物硫酸铁的生成与分解;而且焙烧矿的硫含量也随温度升高而逐渐降低。动力学计算结果表明,在430~975℃的温度范围内,硫精矿氧化焙烧分为4个阶段进行,在前3个阶段,脱硫反应机理均符合Avrami-Erofeev方程,为随机成核和随后生长的化学反应控制,只是反应级数和表观活化能在不同阶段各不相同;在第4阶段,脱硫反应机理符合Z-L-T方程,为残余硫化物的三维扩散控制,反应的表观活化能分别为10.812和9.920kJ/mol,在4个温度段中是最低的。
Aiming at the problem of sulfur removal from sulfur concentrate, the kinetics of the roasting reaction of low-grade sulfur concentrate under oxygen-rich condition was studied. XRD, SEM and EDS were used to analyze the variation of ore phase in the process of oxidative roasting of sulfur concentrate. At the same time, kinetic parameters of desulfurization reaction were calculated by AcharBrindley-Sharp-Wendworth differential method and Coats-Redfern integral method, respectively, according to the DSC and TG curves of thermal analysis. The reaction mechanism of desulfurization of sulfur concentrate at different temperature was determined. The results show that with the increase of temperature, the complex sulfur concentrate is gradually oxidized to hematite, which is accompanied by the formation and decomposition of intermediate product ferric sulfate. The sulfur content of roasted ore also decreases with the increase of temperature. Kinetic calculations show that the pyrite roasting process is divided into four stages in the temperature range of 430 ~ 975 ℃. In the first three stages, the desulfurization reaction mechanism is in accordance with the Avrami-Erofeev equation. For the random nucleation and subsequent In the fourth stage, the mechanism of desulfurization reaction accords with the ZLT equation, which is the three-dimensional diffusion control of the residual sulphides, and the apparent activation energy of the reaction respectively Of 10.812 and 9.920 kJ / mol, the lowest among the four temperature ranges.