Inorganic Chemicals Industry ›› 2025, Vol. 57 ›› Issue (9): 88-95.doi: 10.19964/j.issn.1006-4990.2024-0461

• Environment·Health·Safety • Previous Articles     Next Articles

Study on removing impurity and whitening phosphogypsum after flotation by sulfuric acid coupling silane coupling agent

CHEN Yuanzhi1(), LI Rui1, LI Yubiao1,2(), WU Xiaoyong1, WU Kaizhen1, XUE Lutao1, CHI Ru’an2   

  1. 1. School of Resources and Environmental Engineering,Wuhan University of Technology,Wuhan 430070,China
    2. Hubei Three Gorges Laboratory,Yichang 443000,China
  • Received:2024-08-20 Online:2025-09-10 Published:2024-10-16
  • Contact: LI Yubiao E-mail:3044340341@qq.com;yubiao.li@whut.edu.cn

Abstract:

In order to alleviate the problem of phosphogypsum stockpiling pollution and promote the mass utilization of phosphogypsum,sulfuric acid coupled with silane coupling agent was used to further remove impurities and whitening of phosphogypsum after flotation.The results showed that the optimum conditions for the impurity removal and whitening process were as follows:the sulfuric acid mass fraction of 30%,acid leaching solution-solid ratio of 5∶1,acid leaching temperature of 80 ℃,acid leaching time of 30 min,silane coupling agent fraction of 5%,silane coupling agent reaction temperature of 80 ℃ and silane coupling agent reaction time of 60 min.Under this condition,the purification effect was remarkable,and the whiteness of the sample could be increased from 65.19% to 91.91%.In the process of impurity removal and whitening,fluorine and phosphorus impurities were mainly removed by reaction with sulfuric acid.Silicon and organic impurities were mainly adsorbed by the silane coupling agent and aggregated into large particles,which were filtered out.The whiteness and purity of phosphogypsum after impurity removal by this process were close to those of natural gypsum,and its application prospects in related industries such as building materials,papermaking,agriculture,rubber,heat-resistant and reinforced insulation materials were significantly improved,which had certain guiding significance for the realization of the mass utilization of phosphogypsum.

Key words: phosphogypsum, impurity removal, whitening, acid leaching, silane coupling agent

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