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| Study on Thermodynamics of Alkaline Roasting of Acid Leaching High-silica Slag in Copper Smelting Process |
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Received:June 03, 2024
Revised:June 19, 2024
Accepted:June 20, 2024
Published Online:November 17, 2024
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| DOI：doi：10.3969/j.issn.1007-7545.2024.12.004 |
| KeyWord:pyrometallurgical process of copper; high silica slag; alkaline roasting; thermodynamics; phase diagram |
| Author | Institution |
| RAO Jian |
江西理工大学 |
| LI Mingdong |
江西理工大学 |
| YAN Kang |
江西理工大学 |
| ZHANG Jian |
吉林紫金铜业有限公司 |
| WANG Hongbo |
吉林紫金铜业有限公司 |
| WANG Mengkai |
江西理工大学 |
| ZHANG Zhongtang |
江西理工大学 |
| YU Qunbo |
矿冶科技集团有限公司 |
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| Abstract: |
| A large amount of copper slag is produced in the pyrometallurgical process of copper smelting, and a substantial quantity of high-silica slag is produced after the recovery of valuable metals such as copper by acid leaching. In order to realize both the harmless disposal of high-silica slag and the recovery utilization of silicon, thermodynamic software Factsage 7.3 and HSC 6.0 were used to calculate and construct ΔG—T diagrams, phase equilibrium distribution diagrams, and phase diagrams of Na2O-SiO2-FeO system during the main reactions involved in the alkaline roasting process for high-silica slag. The results indicate that variations in roasting temperature and ω(Na2O)/ω(SiO2) can significantly affect the roasting transformation process and product phase composition. Theoretically, the optimization conditions for SiO2 transformation are determined to be a roasting temperature range of 800—900 ℃ with ω(Na2O)/ω(SiO2)=0.41—0.64. Furthermore, impurities such as Al and Fe were found to participate in the reaction process within high-silica slag, and insoluble impurity NaAlSiO4 being formed prior to soluble impurity Na2FeO2. According to the results of thermodynamic analysis, validation tests were carried out. The results show that the leaching rate of silicon reaches 88.56% under the conditions including excess coefficient of sodium carbonate of 0.9 times of the theoretical total amount of SiO2, Al and Fe, roasting temperature of 850 ℃, and roasting time of 2 h. |
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