Abstract
Dielectric properties and heating characteristics of stibnite concentrate and pure antimony compounds were assessed. Stibnite concentrate and Sb2S3 have high dielectric properties and heating efficiency while Sb2O4 and Sb2O3 are relatively low. Sb2O5 is high from 25 to 300 °C and sharply decreases due to decomposition. Microwave heating process in air has four stages and the roasting process appears at the third stage with corresponding phase changes as Sb2S3 → Sb2O3 → Sb2O5 → Sb2O4. XRD and SEM-EDS results show that Sb2S3 is thoroughly oxidized to Sb2O3 before 400 °C and Sb2O3 is further oxidized into Sb2O4 above 500 °C. Sb2O4 reacts with Fe2O3 above 800 °C to form FeSbO4. Microwave heating mechanism shows FeS2 is the main absorber from 25 to 300 °C, and Sb2S3 was the main absorber above 331.6 °C, indicating theoretical basis for microwave selective roasting stibnite concentrate to produce antimony oxide powder.
Original language | British English |
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Pages (from-to) | 630-640 |
Number of pages | 11 |
Journal | Powder Technology |
Volume | 379 |
DOIs | |
State | Published - Feb 2021 |
Keywords
- Dielectric properties
- Heating mechanism
- Microwave roasting
- Stibnite concentrate