Zhu Ganyu, Yang Yunrui, He Lei, Li Huiquan, Meng Ziheng, Zheng Guangming, Li Fang, Su Xiaodan, Xi Benjun, Li Zhongjun
CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Strategic Metal Resources Green Recycling and Utilization, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Omega. 2023 Jul 27;8(31):28122-28132. doi: 10.1021/acsomega.3c01168. eCollection 2023 Aug 8.
Phosphogypsum, as a byproduct of wet-process phosphoric acid reaction, has caused many environmental pollution problems. To improve the property and purity of phosphogypsum in the wet-process phosphoric acid process, a liquid-solid-liquid three-phase acid hydrolysis synergistic extraction reaction system was established by adding a certain amount of extractant in the actual production process. In order to study the extraction effect and residue of impurities in the reaction system, the phase, morphology, and impurity occurrences of phosphogypsum were systematically analyzed. The results showed that when the reaction time was 7 h, the reaction temperature was 80 °C, the reaction speed was 200 r/min, the volume ratio of the extractant to diluent (dilution ratio) was 1:4 and the volume ratio of the oil phase/aqueous phase (O/A ratio) was 1:1, PO conversion was the highest in phosphate rock, and the residual PO content in phosphogypsum was as low as 0.36%. The morphology of the phosphogypsum crystal was uniform and coarse long strip. The main forms of residual impurities were silicate, aluminum fluoride with crystal water, aluminate, phosphate, and fluoride. Meanwhile, the residual amount of main impurities in phosphogypsum was significantly reduced. Through this novel method, the property of phosphogypsum can be improved through the generation process and is greatly beneficial for its utilization and the recycling development of the wet-process phosphoric acid industry.
磷石膏作为湿法磷酸反应的副产物，引发了诸多环境污染问题。为提高湿法磷酸工艺中磷石膏的性能和纯度，在实际生产过程中通过添加一定量萃取剂建立了液 - 固 - 液三相酸水解协同萃取反应体系。为研究反应体系中的萃取效果和杂质残留情况，对磷石膏的相组成、形貌及杂质赋存状态进行了系统分析。结果表明，当反应时间为7 h、反应温度为80℃、反应转速为200 r/min、萃取剂与稀释剂的体积比（稀释比）为1:4且油相/水相体积比（O/A比）为1:1时，磷矿中PO转化率最高，磷石膏中残留PO含量低至0.36%。磷石膏晶体形貌均匀且呈粗大长条状。残留杂质的主要形态为硅酸盐、含结晶水的氟化铝、铝酸盐、磷酸盐和氟化物。同时，磷石膏中主要杂质的残留量显著降低。通过这种新方法，可在磷石膏生成过程中改善其性能，对其综合利用及湿法磷酸行业的循环发展极为有利。
