A new technology for production of high purity paratungstate ammonium from low grade tungsten concentrate

Abstract

A new technological process for production of paratungstate ammonium from low grade tungsten concentrate with a high content of calcium and impurities has been studied. The experiments show that average tungsten leaching efficiency of more than 96.92% can be obtained with a low NaOH consumption by using the mechanical activating caustic decomposition, and the content of main impurities (P, As, Si) in Na₂WO₄ solution obtained is competitive with that from standard wolframite concentrate by traditional caustic decomposition. After recovering caustic soda by crystallization, impure Na₂WO₄ solution is changed to (NH₄)₂WO₄ solution by ion exchange method. Molybdenum may be removed from (NH₄)₂WO₄ solution by new ion exchange method. Finally, paratungstate ammonium of high purity is obtained. This technology has the advantages of short technological process, high recovery of tungsten, high economic and social benifits.

Keywords

low grade tungsten concentrate / mechanical activating caustic decomposition / ion exchange / paratungstate ammonium

References

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