Carbothermic Reduction Kinetics of Phosphorous Vaporization from Tri-calcium Phosphate (TCP) Under Microwave Rapid Heating With/Without the Presence of Fe{sub 3}O{sub 4}
- Tohoku University, Graduate School of Environmental Studies (Japan)
- Tohoku University, Department of Materials Science and Engineering (Japan)
The kinetics of vapor phase dephosphorization from tri-calcium phosphate (TCP) by carbothermic reduction was studied with and without the presence of Fe{sub 3}O{sub 4}. Microwave heating was utilized to obtain large variations in the heating rate (HR). In the reduction of TCP alone, the phosphorous removal fraction (RF; equal to ∆P{sub 2}O{sub 5}/P{sub 2}O{sub 5}{sup 0}, where ∆P{sub 2}O{sub 5} is the weight change and P{sub 2}O{sub 5}{sup 0} is the P{sub 2}O{sub 5} weight before heating) decreased as the HR increased. In other words, a shorter residence time at a high temperature resulted in a smaller reduction fraction of TCP. An apparently third-order reaction was postulated to account for the kinetics using a fitting simulation based on the additive law of the reaction progress. On the other hand, the phosphorous removal (dephosphorization) rate (RR; equal to ∆P{sub 2}O{sub 3}/t{sub MW}, where t{sub MW} is the microwave heating time period) increased as the HR increased above 1200 °C. The reduction ratio of Fe{sub 3}O{sub 4} above 1100 °C is higher than 97 pct regardless of the heating rate. The reduction of TCP in the presence of Fe{sub 3}O{sub 4} showed that RF increased slightly with increasing HR despite a shorter residence time at a high temperature. The RR also increased with the HR even though RF decreased to half of the values observed in the cases without Fe{sub 3}O{sub 4} for temperatures above 1200 °C. The practicality and optimal operation conditions of phosphorus vapor removal were discussed.
- OSTI ID:
- 22857944
- Journal Information:
- Metallurgical and Materials Transactions B, Process Metallurgy and Materials Processing Science, Vol. 49, Issue 3; Other Information: Copyright (c) 2018 The Minerals, Metals & Materials Society and ASM International; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); ISSN 1073-5615
- Country of Publication:
- United States
- Language:
- English
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