Inorganic Chemicals Industry ›› 2022, Vol. 54 ›› Issue (7): 129-134.doi: 10.19964/j.issn.1006-4990.2021-0654

• Environment·Health·Safety • Previous Articles     Next Articles

Study on preparation of phosphoric acid by leaching fluoride residue from wet-process phosphoric acid with organic solvents

FU Ziqi1(), ZHANG Cheng1, SHENG Yong2, JI Lijun1()   

  1. 1.School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China
    2.Sinochem Yunlong Co. ,Ltd.
  • Received:2021-10-27 Online:2022-07-10 Published:2022-07-14
  • Contact: JI Lijun E-mail:17621965230@163.com;jilijun@ecust.edu.cn

Abstract:

The fluoride residue is a solid waste produced in the chemical defluorination process of wet-process phosphoric acid.The effects of leaching time,temperature and liquid-solid ratio on the leaching ratio of P2O5 and F and the phosphor-fluorine ratio[m(P2O5)/m(F)] were studied by using methanol,ethanol and acetone to leach the fluoride residue for recycling phosphoric acid.The suitable leaching conditions were obtained.After the leaching solution was evaporated and concentrated to recover the leaching agent,the concentrated solution all could meet the requirements of the m(P2O5)/m(F) of wet-process phosphoric acid for producing feed-grade calcium hydrogen phosphate.Considering the cost of the leaching solvents,the leaching ratio of P2O5 and m(P2O5)/m(F),methanol was selected as the optimal leaching solvent,and the leaching conditions of methanol was optimized by response surface methodology.Under the optimized conditions,the leaching ratio of P2O5 was 97.13%,and the m(P2O5)/m(F) of the leaching solution was 51.62.After 5 cycles of solvent recovery and leaching,recovered methanol still had good leaching effect on the fluoride residue.

Key words: wet-process phosphoric acid, fluoride residue, leaching, response surface methodology

CLC Number: