AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES
A bauxite reserve with an Al2O3 grade less than 50% is classified as low-grade bauxite due to the presence of impurities such as silica and iron oxide, thus pretreatment before concentration (Bayer process) is required to reduce SiO2 and Fe2O3. Hence, this study investigates the feasibility of remov...
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University of Zagreb
2025-01-01
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| Series: | Rudarsko-geološko-naftni Zbornik |
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| Online Access: | https://hrcak.srce.hr/file/481991 |
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| author | Amirhossein Ashrafi Asghar Azizi Zahra Bahri |
| author_facet | Amirhossein Ashrafi Asghar Azizi Zahra Bahri |
| author_sort | Amirhossein Ashrafi |
| collection | DOAJ |
| description | A bauxite reserve with an Al2O3 grade less than 50% is classified as low-grade bauxite due to the presence of impurities such as silica and iron oxide, thus pretreatment before concentration (Bayer process) is required to reduce SiO2 and Fe2O3. Hence, this study investigates the feasibility of removing SiO2 and Fe2O3 from a low-grade bauxite ore using magnetic separation and flotation processes. Different magnetic methods were utilized to eliminate iron impurities, and the results indicated that the high-gradient magnetic separation (HGMS) with an intensity of 18000 Gauss had the best output in reducing Fe2O3 with 18.03% Fe2O3 content and a 31.15% removal rate. In the next step, reverse and direct flotation techniques were employed to remove silica from the sample. The findings showed that the highest removal efficiency of SiO2 was achieved using the reverse flotation process at 750 g/t Armac C collector, 1200 g/t starch, 40 g/t MIBC and 11 pulp pH. Ultimately, the HGMS followed by reverse flotation with an Armac C collector (750 g/t) was implemented on the bauxite sample, and the content of Fe2O3, and SiO2, silica removal efficiency, and Al2O3/SiO2 mass ratio was found to be 17.76, and 22.11%, 45.22% and 1.63, respectively, indicating that HGMS followed by flotation is not effective enough in reducing iron oxide and silica, and therefore requires further pretreatment and/or the study of a suitable alternative method. The behaviour observed may be because iron oxide and silica minerals were fine-grained diseminated in the bauxite sample. |
| format | Article |
| id | doaj-art-307d6e9e274f4c0fb3aaf1d23a8c9b99 |
| institution | Kabale University |
| issn | 0353-4529 1849-0409 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | University of Zagreb |
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| series | Rudarsko-geološko-naftni Zbornik |
| spelling | doaj-art-307d6e9e274f4c0fb3aaf1d23a8c9b992025-08-20T03:50:12ZengUniversity of ZagrebRudarsko-geološko-naftni Zbornik0353-45291849-04092025-01-0140311913010.17794/rgn.2025.3.9AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSESAmirhossein Ashrafi0Asghar Azizi1Zahra Bahri2Faculty of Mining, Petroleum & Geophysics Engineering, Shahrood University of Technology, Shahrood, IranFaculty of Mining, Petroleum & Geophysics Engineering, Shahrood University of Technology, Shahrood, IranDepartment of Control and Modeling of Mineral Processing Systems, Institute of Mineral Processing, Academic Center for Education, Culture & Research (ACECR) at Tarbiat Modares, Tehran, IranA bauxite reserve with an Al2O3 grade less than 50% is classified as low-grade bauxite due to the presence of impurities such as silica and iron oxide, thus pretreatment before concentration (Bayer process) is required to reduce SiO2 and Fe2O3. Hence, this study investigates the feasibility of removing SiO2 and Fe2O3 from a low-grade bauxite ore using magnetic separation and flotation processes. Different magnetic methods were utilized to eliminate iron impurities, and the results indicated that the high-gradient magnetic separation (HGMS) with an intensity of 18000 Gauss had the best output in reducing Fe2O3 with 18.03% Fe2O3 content and a 31.15% removal rate. In the next step, reverse and direct flotation techniques were employed to remove silica from the sample. The findings showed that the highest removal efficiency of SiO2 was achieved using the reverse flotation process at 750 g/t Armac C collector, 1200 g/t starch, 40 g/t MIBC and 11 pulp pH. Ultimately, the HGMS followed by reverse flotation with an Armac C collector (750 g/t) was implemented on the bauxite sample, and the content of Fe2O3, and SiO2, silica removal efficiency, and Al2O3/SiO2 mass ratio was found to be 17.76, and 22.11%, 45.22% and 1.63, respectively, indicating that HGMS followed by flotation is not effective enough in reducing iron oxide and silica, and therefore requires further pretreatment and/or the study of a suitable alternative method. The behaviour observed may be because iron oxide and silica minerals were fine-grained diseminated in the bauxite sample.https://hrcak.srce.hr/file/481991low-grade bauxitesilicaremoval efficiencymagnetic separationreverse flotation |
| spellingShingle | Amirhossein Ashrafi Asghar Azizi Zahra Bahri AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES Rudarsko-geološko-naftni Zbornik low-grade bauxite silica removal efficiency magnetic separation reverse flotation |
| title | AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES |
| title_full | AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES |
| title_fullStr | AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES |
| title_full_unstemmed | AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES |
| title_short | AN INVESTIGATION INTO THE PRETREATING OF A LOW-GRADE BAUXITE ORE USING MAGNETIC SEPARATION AND FLOTATION PROCESSES |
| title_sort | investigation into the pretreating of a low grade bauxite ore using magnetic separation and flotation processes |
| topic | low-grade bauxite silica removal efficiency magnetic separation reverse flotation |
| url | https://hrcak.srce.hr/file/481991 |
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