Complexation extraction of scheelite and transformation behaviour of tungsten-containing phase using H2SO4 solution with H2C2O4 as complexing agent
| Autor: | Hao Guo, Hua-jin Cheng, Qingsheng Liu, Xuezhong Wang, Tao Tu |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Chemistry
Oxalic acid Metals and Alloys chemistry.chemical_element Sulfuric acid Tungsten Geotechnical Engineering and Engineering Geology Condensed Matter Physics Tungsten trioxide chemistry.chemical_compound Tungstate Leaching (chemistry) Scheelite Materials Chemistry Tungstic acid Nuclear chemistry |
| Zdroj: | Transactions of Nonferrous Metals Society of China. 31:3150-3161 |
| ISSN: | 1003-6326 |
| DOI: | 10.1016/s1003-6326(21)65724-2 |
| Popis: | The extraction of tungsten from scheelite was carried out using a sulfuric acid solution with oxalic acid as the chelating agent. Tungsten was obtained in the form of highly soluble hydrogen aqua oxalato tungstate (H2[WO3(C2O4)·H2O]) during the leaching process, while calcium remained in the residue as calcium sulfate dihydrate (CaSO4·2H2O). About 99.2% of the tungsten was leached at 70 °C, 1.5 mol/L sulfuric acid, 1 mol/L oxalic acid, a liquid/solid ratio of 25:1 (mL/g), an oxalic acid to sulfuric acid molar ratio of 1:1, a stirring speed of 300 r/min and a leaching time of 2 h. H2[WO3(C2O4)·H2O] was thermally decomposed into tungstic acid (H2WO4), and tungsten trioxide (WO3) was directly produced by calcining H2WO4 at 700 °C for 2 h. The surface chemical reaction was determined to be the controlling step during tungsten leaching, and the apparent activation energy was calculated to be 51.43 kJ/mol. |
| Databáze: | OpenAIRE |
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