Abstract: Thermal analysis was used in the investigation of reaction process for sulfuric acid production from phosphogypsum. The effects of different raw material C/CaSO4 molar ratios on reaction process and reaction temperature were investigated with TG-DTA thermal analyzer. Through the comparison for the difference between experimental and theoretical weight loss values，it was found that CaSO4 was reduced to CaS by C during the first reaction step when raw material molar ratios was 0.4 and 0.5. At the same time，the reaction temperature decreased with increasing raw material molar ratio. However，the products were CaO and CO，etc. during the first reaction step when raw material molar ratio increased to 0.6. XRD results of samples also confirmed that the reaction resultants included CaS and CaO respectively. Therefore it was concluded that the use of thermal analysis in the investigation of reaction process for sulfuric acid production from phosphogypsum was feasible. Finally a discussion on the reaction mechanism was given.

摘要： 采用热分析方法研究磷石膏制酸过程中CaSO4与焦炭的反应进程。在TG-DTA热分析仪上研究原料配比（C与CaSO4摩尔比）对反应进程及反应温度的影响。通过比较化学反应的实际失重量与理论失重量，发现原料配比为0.4和0.5时，反应先生成CaS，且反应温度随原料配比增加而降低。当原料配比增至0.6时，反应先生成CaO、CO。反应产物的XRD表征也进一步证实分别生成了CaS和CaO，因此可以认为热分析方法用于磷石膏制酸反应研究是可行的。最后对反应机理进行了初步的探讨。