Direct Pressure Alkaline Leaching of Scheelite Ores Concentrates
| Autor: | Aurora Futuro, Patrícia Leitão, António Fiúza, Lurdes Dinis, Cristina Vila, Anthony S. Danko |
|---|---|
| Přispěvatelé: | Faculdade de Engenharia |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
business.industry
Mechanical Engineering Final product 0211 other engineering and technologies Metals and Alloys 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Geotechnical Engineering and Engineering Geology chemistry.chemical_compound chemistry Control and Systems Engineering Reagent Scheelite Materials Chemistry Environmental science Carbonate Leaching (metallurgy) 0210 nano-technology Process engineering business Sodium carbonate Dissolution Operating cost 021102 mining & metallurgy |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| Popis: | The average global recovery rates for processing scheelite ores by physical methods are normally in the range 50 to 70%, and it is problematic to attain a minimum grade of 60% WO3 in the concentrates without penalizing further this yield. Direct hydrometallurgical processing of low-grade concentrates or medium- to high-grade ores may become an interesting global economic alternative as it allows increasing the recovery rate, avoiding major penalizations due to the grade of the concentrate and increasing the added value of the final product. Leaching of scheelite by sodium carbonate presents several advantages such as its selectivity regarding the dissolution of troubling metals like iron and aluminium, allowing for a simple and flexible process diagram. However, it has the disadvantage that it is performed at high temperature and pressure with a high consumption of reagents. The feasibility of leaching is appraised by the extraction yield and selectivity, but also by the operating cost. Considering these aspects, a relevant objective of the research was to transform alkaline pressure leaching into a feasible processing alternative directly applicable to both medium- and high-grade ores and simultaneously to low- and high-grade concentrates produced by physical methods. The research used ore samples and low-grade concentrates from a typical skarn orebody as well as high-grade concentrates from a chalcopyrite-scheelite orebody. Different operating conditions were tested. Temperature, pressure and reagent concentration showed to be fundamental, but not exclusive, in determining the leaching behaviour. The operating conditions are milder than the ones generally proposed in the literature or currently in use in industry, but with higher carbonate consumptions. The research was oriented towards potential industrial implementation allowing for the application of optimization methods and straight scale-up to pilot-plan design and project. |
| Databáze: | OpenAIRE |
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