Inorganic Chemicals Industry ›› 2023, Vol. 55 ›› Issue (6): 85-91.doi: 10.19964/j.issn.1006-4990.2022-0546

• Environment·Health·Safety • Previous Articles     Next Articles

Feasibility analysis of calcination and decomposition process of phosphogypsum in circulating fluidized bed

ZHANG Lei1(), LI Meng1,2, XIANG Wenguo3, HU Jun3,4(), CHEN Shiyi3, DUAN Lunbo3   

  1. 1. SINOPEC Nanjing Engineering & Construction Incorporation,Nanjing 210049,China
    2. College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310058,China
    3. School of Energy and Environment,Southeast University,Nanjing 210096,China
    4. School of Petroleum and Natural Gas Engineering,School of Energy,Changzhou University,Changzhou 213164,China
  • Received:2022-09-09 Online:2023-06-10 Published:2023-06-14

Abstract:

Phosphogypsum produced from phosphoric acid production,as industrial solid wastes,can be used for the production of sulfuric acid and calcium based materials,which is a sustainable technological route.The process of phosphogypsum decomposition in the coal-fired circulating fluidized bed to produce sulfuric acid and calcium-based materials after granulation was presented.The feasibility of the process was verified from the aspects of the mass energy balance of the process and the decomposition desulfurization performance of phosphogypsum calcined from coal under different working conditions.Thermodynamic calculation results showed that the process could realize self heating operation.CaO was generated from the decomposition and desulfurization of calcined phosphogypsum.O2/H2O and O2/CO2 were suitable fluidization and oxidation media.The volume fraction of SO2 in the dry gas at the reactor outlet could reach 33%,which was suitable for sulfuric acid production.The excessive reducing weak oxidizing atmosphere could realize the decomposition and desulfurization of phosphogypsum at 1 100 ℃,which was lower than the existing decomposition process temperature of phosphogypsum.Under the reaction conditions of 1 100 ℃,phosphogypsum/coal mass ratio of 4∶1,O2/CO2 or O2/H2O with 1% O2 volume fraction,the main components of solid residue were CaO,CaO·CaSiO3.The research results preliminarily showed that the technology of phosphogypsum calcination and decomposition by circulating fluidized bed to produce sulfuric acid and calcium based materials was feasible.

Key words: phosphogypsum, calcium-based materials, decomposition and desulphurization, circulating fluidized bed

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