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Effect of potassium feldspar on the decomposition rate of phosphogypsum
Author(s) -
Lu Dinghui,
Chen Qianlin,
Li Cuiqin,
Gong Shang
Publication year - 2021
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.6549
Subject(s) - decomposition , phosphogypsum , coke , calcination , chemistry , potassium , feldspar , mineralogy , nuclear chemistry , raw material , materials science , metallurgy , organic chemistry , catalysis , quartz
Abstract Background Phosphogypsum (PG) is a solid waste from a wet process of phosphoric acid and its main component is CaSO 4 ·2H 2 O. However, the temperature of PG decomposition is above 1200 °C. In this study, the decomposition temperature of PG was decreased using a small amount of coke as reducing agent, and the decomposition rate of PG can be further increased using potassium feldspar (K‐feldspar) as an additive to form a eutectic mixture with PG in nitrogen atmosphere. Results A high PG decomposition rate of 99.40% was obtained at 1150 °C for 25 min, when the mass ratio of coke to PG and K‐feldspar to PG was 0.07 and 0.43, respectively. Compared with the addition of coke alone (coke/PG = 0.07) as the reducing agent, the decomposition rate of PG was increased by 35.40%. The HSC Chemistry software 8 was used to calculate the equilibrium compositions of the PG @K‐feldspar @coke system, and the decomposition rate of 99.77% was obtained at 1150 °C by calculation. The experimental results are basically consistent with the thermodynamic equilibrium calculation. Conclusion The PG and K‐feldspar are fully utilized by calcination. The decomposition reaction of PG can proceed via the continuous consumption of CaO and CaS by K‐feldspar, which increased the decomposition rate of PG. The thermodynamic calculation results showed a good agreement between the equilibrium value calculated and the experimental data obtained. Furthermore, the calcined products can be used as an agricultural potassium fertilizer. © 2020 Society of Chemical Industry (SCI)