This hydrometallurgy paper recovers vanadium and tungsten from leach liquors of spent catalysts used for nitrogen oxide control, using a quaternary ammonium extractant. The feed contained about 7 g/L tungsten and 0.7 g/L vanadium. The work concerns metal recycling, not food or human exposure.
Key numbers
This paper reports no numerical findings relevant to tungsten exposure.
Methods (brief)
Solvent extraction and stripping tests varying pH, extractant level, diluent, chloride, temperature and stripping reagents, with McCabe-Thiele analysis of stage requirements.
Evidence fitness
Off-topic for dietary exposure: an industrial recovery paper that does not support dietary exposure or toxicity claims for tungsten.
Limitations
Process chemistry only; no environmental or biological measurements.
Related evidence
Update history
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