化工学报 ›› 2023, Vol. 74 ›› Issue (4): 1805-1817.DOI: 10.11949/0438-1157.20221358

• 材料化学工程与纳米技术 • 上一篇    下一篇

湿法磷酸半水工艺考察与石膏结晶过程研究

苏晓丹1(), 朱干宇2,3(), 李会泉2,4, 郑光明5, 孟子衡2,3, 李防5, 杨云瑞2,4, 习本军3, 崔玉1()   

  1. 1.济南大学化学化工学院,山东 济南 250022
    2.中国科学院过程工程研究所,绿色过程与工程重点实验室,战略金属资源绿色循环利用国家工程研究中心,北京 100190
    3.湖北三峡实验室,湖北 宜昌 443000
    4.中国科学院大学化学工程学院,北京 100049
    5.宜都兴发化工有限公司,湖北 宜昌 443000
  • 收稿日期:2022-10-14 修回日期:2023-03-20 出版日期:2023-04-05 发布日期:2023-06-02
  • 通讯作者: 朱干宇,崔玉
  • 作者简介:苏晓丹(1997—),女,硕士研究生,suxiaodan@ipe.ac.cn
  • 基金资助:
    国家自然科学基金项目(22078344);湖北三峡实验室开放/创新基金项目(SC211001)

Optimization of wet process phosphoric acid hemihydrate process and crystallization of gypsum

Xiaodan SU1(), Ganyu ZHU2,3(), Huiquan LI2,4, Guangming ZHENG5, Ziheng MENG2,3, Fang LI5, Yunrui YANG2,4, Benjun XI3, Yu CUI1()   

  1. 1.School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong, China
    2.CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
    3.Hubei Three Gorges Laboratory, Yichang 443000, Hubei, China
    4.School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
    5.Yidu Xingfa Chemical Company Limited, Yichang 443000, Hubei, China
  • Received:2022-10-14 Revised:2023-03-20 Online:2023-04-05 Published:2023-06-02
  • Contact: Ganyu ZHU, Yu CUI

摘要:

湿法磷酸半水工艺可生产高浓度磷酸[w(P2O5)>40%(质量)],但在半水反应阶段磷矿易发生钝化,半水石膏结晶粒径小,造成工艺后端过滤困难,磷回收率降低。以湖北典型中低品位磷矿为原料,系统考察了半水工艺中SO42-浓度、磷酸浓度、反应温度等条件对半水石膏结晶物相、形貌及粒径的影响规律,分析了优化条件下石膏杂质赋存与含量变化。结果表明,半水反应中液相硫酸、磷酸浓度会引起半水石膏物相、形貌、粒径变化,磷硫浓度提高会导致石膏晶体形貌由柱状变化为棒状、片状,粒径从70 μm减小到10 μm。优化工艺条件下,半水石膏较原工艺石膏P2O5含量降低至1.39%(质量),磷的主要存在形式为难溶性磷酸盐,同时F含量降低至0.44%(质量),其以CaF2、AlF3等难溶物形式存在于石膏,其他杂质含量均有所降低。本研究可为半水工艺生产过程参数优化及半水石膏品质提升提供参考。

关键词: 湿法磷酸, 半水工艺, 结晶, 过程控制, 优化

Abstract:

Hemihydrate wet process phosphoric acid can produce w(P2O5)>40%(mass) phosphoric acid but in the reaction stage, the phosphate ore is prone to coating formation, the crystal size of hemihydrate phosphogypsum is small, resulting in difficult filtration and reduced phosphorus recovery. Taking typical mid-and low-grade phosphate rock from Hubei province as raw material, the conditions such as SO42- concentration, phosphoric acid concentration and reaction temperature in hemihydrate process were investigated, and the crystal phase and morphology and particle size change rule of semi-aqueous gypsum were obtained. In the hemihydrate reaction, with the concentration of sulfuric acid and phosphoric acid in the liquid phase increase, the hemihydrate phosphogypsum is more prone to phase transformation. The morphology of hemihydrate phosphogypsum changes from hexagonal prism to rod and flake, and the particle size decreases from 70 μm to 10 μm. Under optimal conditions, the content of P, F and other elements in hemihydrate phosphogypsum can be effectively reduced. The P2O5 content of hemihydrate phosphogypsum was reduced to 1.39%(mass) and the main form of P was insoluble phosphate. The F content was reduced to 0.44%(mass), which existed in hemihydrate phosphogypsum in the form of poorly soluble substances such as CaF2 and AlF3. The form of impurities is simple, which is convenient for the subsequent purification and utilization of gypsum. The above research brings new ideas for the stable operation of hemihydrate process and the quality improvement of hemihydrate phosphogypsum.

Key words: wet process phosphoric acid, hemihydrate process, crystallization, process control, optimization

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