One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions
Black mineral sands are widely used to obtain titanium dioxide, titanium, and, more recently, a variety of iron–titanium oxide nanostructures. Highly corrosive mineral acids or alkalis are commonly employed for this purpose. Hence, it is desirable to find eco-friendly ways to process these minerals,...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/3/306 |
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| author | Carla S. Valdivieso-Ramírez Patricia I. Pontón Anja Dosen Bojan A. Marinkovic Victor H. Guerrero |
| author_facet | Carla S. Valdivieso-Ramírez Patricia I. Pontón Anja Dosen Bojan A. Marinkovic Victor H. Guerrero |
| author_sort | Carla S. Valdivieso-Ramírez |
| collection | DOAJ |
| description | Black mineral sands are widely used to obtain titanium dioxide, titanium, and, more recently, a variety of iron–titanium oxide nanostructures. Highly corrosive mineral acids or alkalis are commonly employed for this purpose. Hence, it is desirable to find eco-friendly ways to process these minerals, deriving high-added value materials. In this study, an Ecuadorian mineral sand precursor (0.6FeTiO<sub>3</sub>∙0.4Fe<sub>2</sub>O<sub>3</sub> solid solution) was treated with oxalic acid aqueous solutions under subcritical water conditions. The synthesis was conducted in a batch reactor operating at 155 °C, 50 bar, and 700 rpm for 12 h, varying the oxalic acid concentration (0.1, 0.5 to 1.0 M). The as-obtained compounds were physically separated, dried, and analyzed by X-ray powder diffraction, scanning electron microscopy, and Raman spectroscopy. The characterization showed that the precursor was completely converted into two main products, ferrous oxalate, and titanium dioxide polymorphs. Rutile was always found in the as-synthesized products, while anatase only crystallized with high oxalic acid concentrations (0.5 and 1.0 M). These results open the possibility to develop more sustainable routes to synthesize iron and titanium-based materials with promising applications. |
| first_indexed | 2024-03-09T13:13:46Z |
| format | Article |
| id | doaj.art-267478333bc4425b81b697f6922bb214 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T13:13:46Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-267478333bc4425b81b697f6922bb2142023-11-30T21:38:16ZengMDPI AGMinerals2075-163X2022-02-0112330610.3390/min12030306One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water ConditionsCarla S. Valdivieso-Ramírez0Patricia I. Pontón1Anja Dosen2Bojan A. Marinkovic3Victor H. Guerrero4Department of Materials, Escuela Politécnica Nacional, Quito 170525, EcuadorDepartment of Materials, Escuela Politécnica Nacional, Quito 170525, EcuadorDepartment of Chemical and Materials Engineering, Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rio de Janeiro 38097, BrazilDepartment of Chemical and Materials Engineering, Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rio de Janeiro 38097, BrazilDepartment of Materials, Escuela Politécnica Nacional, Quito 170525, EcuadorBlack mineral sands are widely used to obtain titanium dioxide, titanium, and, more recently, a variety of iron–titanium oxide nanostructures. Highly corrosive mineral acids or alkalis are commonly employed for this purpose. Hence, it is desirable to find eco-friendly ways to process these minerals, deriving high-added value materials. In this study, an Ecuadorian mineral sand precursor (0.6FeTiO<sub>3</sub>∙0.4Fe<sub>2</sub>O<sub>3</sub> solid solution) was treated with oxalic acid aqueous solutions under subcritical water conditions. The synthesis was conducted in a batch reactor operating at 155 °C, 50 bar, and 700 rpm for 12 h, varying the oxalic acid concentration (0.1, 0.5 to 1.0 M). The as-obtained compounds were physically separated, dried, and analyzed by X-ray powder diffraction, scanning electron microscopy, and Raman spectroscopy. The characterization showed that the precursor was completely converted into two main products, ferrous oxalate, and titanium dioxide polymorphs. Rutile was always found in the as-synthesized products, while anatase only crystallized with high oxalic acid concentrations (0.5 and 1.0 M). These results open the possibility to develop more sustainable routes to synthesize iron and titanium-based materials with promising applications.https://www.mdpi.com/2075-163X/12/3/306ferrous oxalatetitanium dioxideoxalate-based reagentferrotitaniferous sandssubcritical water technology |
| spellingShingle | Carla S. Valdivieso-Ramírez Patricia I. Pontón Anja Dosen Bojan A. Marinkovic Victor H. Guerrero One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions Minerals ferrous oxalate titanium dioxide oxalate-based reagent ferrotitaniferous sands subcritical water technology |
| title | One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions |
| title_full | One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions |
| title_fullStr | One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions |
| title_full_unstemmed | One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions |
| title_short | One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions |
| title_sort | one step synthesis of iron and titanium based compounds using black mineral sands and oxalic acid under subcritical water conditions |
| topic | ferrous oxalate titanium dioxide oxalate-based reagent ferrotitaniferous sands subcritical water technology |
| url | https://www.mdpi.com/2075-163X/12/3/306 |
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