Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process
Red mud, which could cause numerous problems to the environment, is a hazardous waste generated from the alumina smelting industry. In general, the storage and harmless utilization of red mud are hard to implement due to its fine particle size and high alkalinity. This study put forward a novel proc...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-03-01
|
| Series: | Minerals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-163X/13/3/452 |
| _version_ | 1797610037020983296 |
|---|---|
| author | Rui Chen Lin Shi Haoyong Huang Jie Yuan |
| author_facet | Rui Chen Lin Shi Haoyong Huang Jie Yuan |
| author_sort | Rui Chen |
| collection | DOAJ |
| description | Red mud, which could cause numerous problems to the environment, is a hazardous waste generated from the alumina smelting industry. In general, the storage and harmless utilization of red mud are hard to implement due to its fine particle size and high alkalinity. This study put forward a novel process to separate iron (MgFe<sub>2</sub>O<sub>4</sub>) and alumina (Al<sub>2</sub>O<sub>3</sub>) in red mud by a magnetization sintering method. The magnesium oxide was added to transform the nonmagnetic Fe<sub>2</sub>O<sub>3</sub> into magnetic MgFe<sub>2</sub>O<sub>4</sub> to achieve physical separation of iron-bearing minerals, and the alumina-bearing minerals were converted into dissoluble NaAlO<sub>2</sub> minerals in a one-step reaction. The atmospheric pressure leaching process was adopted in this study for alumina resource recovery. To achieve clean alumina production, the silicate in the leaching solution was removed by adding the slightly soluble CaSO<sub>4</sub>, and the entire process becomes clean and harmless. The feasibility of the process was verified by thermodynamic analysis, and a series of experiments were performed to detect the optimum MgO/(Fe<sub>2</sub>O<sub>3</sub> + MgO) ratio and the calcining and leaching conditions. The morphological and mineralogical characteristics of modified red mud, leaching red mud, and magnetic separation product were studied by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS). It was observed that under the optimal conditions with MgO/(Fe<sub>2</sub>O<sub>3</sub> + MgO) of 14.89% to recover iron and aluminum, the corresponding recovery rates were 67.54% and 73.01% respectively, and the iron grade was 30.46%. The EDS results showed that the obtained Mg/Fe ratio of the magnetic separation product was 0.4677–0.528, which is slightly different from that of the standard MgFe<sub>2</sub>O<sub>4</sub> at 0.5. This new method can promote the development of comprehensive utilization of red mud and iron production. |
| first_indexed | 2024-03-11T06:08:51Z |
| format | Article |
| id | doaj.art-f8d3ae63a0a948b19f1af59e6c476a3b |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-11T06:08:51Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-f8d3ae63a0a948b19f1af59e6c476a3b2023-11-17T12:48:47ZengMDPI AGMinerals2075-163X2023-03-0113345210.3390/min13030452Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering ProcessRui Chen0Lin Shi1Haoyong Huang2Jie Yuan3School of Environment and Energy, South China University of Technology, Guangzhou 510006, ChinaSchool of Environment and Energy, South China University of Technology, Guangzhou 510006, ChinaSchool of Environment and Energy, South China University of Technology, Guangzhou 510006, ChinaSchool of Environment and Energy, South China University of Technology, Guangzhou 510006, ChinaRed mud, which could cause numerous problems to the environment, is a hazardous waste generated from the alumina smelting industry. In general, the storage and harmless utilization of red mud are hard to implement due to its fine particle size and high alkalinity. This study put forward a novel process to separate iron (MgFe<sub>2</sub>O<sub>4</sub>) and alumina (Al<sub>2</sub>O<sub>3</sub>) in red mud by a magnetization sintering method. The magnesium oxide was added to transform the nonmagnetic Fe<sub>2</sub>O<sub>3</sub> into magnetic MgFe<sub>2</sub>O<sub>4</sub> to achieve physical separation of iron-bearing minerals, and the alumina-bearing minerals were converted into dissoluble NaAlO<sub>2</sub> minerals in a one-step reaction. The atmospheric pressure leaching process was adopted in this study for alumina resource recovery. To achieve clean alumina production, the silicate in the leaching solution was removed by adding the slightly soluble CaSO<sub>4</sub>, and the entire process becomes clean and harmless. The feasibility of the process was verified by thermodynamic analysis, and a series of experiments were performed to detect the optimum MgO/(Fe<sub>2</sub>O<sub>3</sub> + MgO) ratio and the calcining and leaching conditions. The morphological and mineralogical characteristics of modified red mud, leaching red mud, and magnetic separation product were studied by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS). It was observed that under the optimal conditions with MgO/(Fe<sub>2</sub>O<sub>3</sub> + MgO) of 14.89% to recover iron and aluminum, the corresponding recovery rates were 67.54% and 73.01% respectively, and the iron grade was 30.46%. The EDS results showed that the obtained Mg/Fe ratio of the magnetic separation product was 0.4677–0.528, which is slightly different from that of the standard MgFe<sub>2</sub>O<sub>4</sub> at 0.5. This new method can promote the development of comprehensive utilization of red mud and iron production.https://www.mdpi.com/2075-163X/13/3/452red mudharmless utilizationmineralogical analysisMgFe<sub>2</sub>O<sub>4</sub>leaching parameter |
| spellingShingle | Rui Chen Lin Shi Haoyong Huang Jie Yuan Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process Minerals red mud harmless utilization mineralogical analysis MgFe<sub>2</sub>O<sub>4</sub> leaching parameter |
| title | Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process |
| title_full | Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process |
| title_fullStr | Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process |
| title_full_unstemmed | Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process |
| title_short | Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process |
| title_sort | extraction of iron and alumina from red mud with a non harmful magnetization sintering process |
| topic | red mud harmless utilization mineralogical analysis MgFe<sub>2</sub>O<sub>4</sub> leaching parameter |
| url | https://www.mdpi.com/2075-163X/13/3/452 |
| work_keys_str_mv | AT ruichen extractionofironandaluminafromredmudwithanonharmfulmagnetizationsinteringprocess AT linshi extractionofironandaluminafromredmudwithanonharmfulmagnetizationsinteringprocess AT haoyonghuang extractionofironandaluminafromredmudwithanonharmfulmagnetizationsinteringprocess AT jieyuan extractionofironandaluminafromredmudwithanonharmfulmagnetizationsinteringprocess |