磷石膏转氨法制硫酸技术原理与过程评价

Preparation of sulfuric acid from phosphogypsum by ammonium-transferred method:Technical principle and process evaluation

以贵州瓮福磷石膏为原料,探讨了碳酸铵循环法利用磷石膏制取硫酸的改进工艺。通过热重、气相质谱连用技术分析了转氨法关键步骤——硫酸氨分解特征,并指导确定了分解温度以避免不利副反应的发生。通过优化实验,使磷石膏与碳酸铵复分解反应制备硫酸铵的转化率达到92.93%。而硫酸铵与氧化铁固相反应的实验结果表明:420℃,1h时,氨气回收率达86.57%;700℃,1h时,SO3回收率达到93.75%,两步法工艺可以较好的实现氮和硫元素的回收循环。磷石膏转氨法制硫酸,一次性资源消耗和CO2排放量较低,副产品经济价值较高,环境相容性较好,具有更好的工业化前景。

Producing sulfate acid with ammonium-transferred method was studied using phosphogypsum from Wengfu Guizhou Ltd.The decomposition of Ammonium sulfate was analyzed by thermogravimetry-mass spectrum（TG-MS）,and the decomposition temperature was determined to avoid the side reaction.According to results,ammonium sulfate transformation rate can reach 92.93%,recycle rate of NH3 can reach 86.57%at 420℃for 1h,and recycle rate of SO3 can reach 93.75% at 700℃ for 1h.Nitrogen and sulfur are recycled effectively via the process.It turns out that the ammonium-transferred method is best for industrialization of sulfuric acid production.