Experimental Approach for the Characterization of Low-Grade Phosphate Ore Performance in Isothermal Conditions

Autor: Xianfen Li, Qinghui Wu, Huang Run, Junqi Li, Shufang Xie
Rok vydání: 2021
Předmět:
Zdroj: Journal of Sustainable Metallurgy. 7:1736-1747
ISSN: 2199-3831
2199-3823
DOI: 10.1007/s40831-021-00451-2
Popis: The vacuum carbothermal reduction behavior of low-grade phosphate ore was examined using coke powder as a reducing agent. The findings show that the reduction ratio of phosphate ore and the volatilization ratio of P increased with increasing temperature and holding time, of which the reduction temperature had a more significant influence on the reduction degree compared with the holding time. Above 1250 °C, the reaction rate was very high, but after 30 min, the rate of reaction began to slow. At 1080 °C, Ca5(PO4)3F first reacted with a small amount of SiO2 in the ore sample to form Ca3(PO4)2, CaSiO3, and SiF4 (escaped in the form of gas), and Ca3(PO4)2 was subsequently reduced by C. When the temperature reached 1300 °C, a large amount of Ca5(PO4)3F in the phosphate rock started to react with C to produce CaO, P2 (g), CO (g), and CaF2. Via the mutual verification trial-and-error method, it was concluded that the unitary reduction process was under the control of the shrinking core model and diffusion, and the activation energies of the unitary reduction were 124.67 kJ/mol and 265.9 kJ/mol. Meanwhile, the volatilization of P was under the control of the diffusion and shrinking core model, and the activation energies were 604.77 kJ/mol and 339.49 kJ/mol.
Databáze: OpenAIRE
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