Production of high purity molybdenum compounds from a Cu–Mo acid-washed liquor using solvent extraction. Part 1: Laboratory studies

Solvent extraction, using Alamine 304-1 for loading (extraction) and ammonia for stripping, was used for selectively recovering molybdenum from acid wash liquor produced by a Mo processing plant. The results showed that the extraction could be completed in 3 stages, using Alamine 304-1 as the extractant (10%, v/v in Anysol 150 diluent), with almost all the Mo(VI) recovered from an acidic sulfate wash liquor, containing 10–15 g/L Mo(VI), 10 g/L Cu(II) and 2 g/L Fe(III), using an O/A volumetric ratio of 3:2. Using ammonia (12.5%, w/v), at an O/A ratio of 5:1, all the Mo(VI) from an Alamine liquor containing 17.5 g/L Mo could be removed in one strip, yielding a solution with 87.0 g/L Mo(VI). High purity (>99.9%) MoO3 and CaMoO4 were produced from this pure liquor via an intermediate hydrate precipitate (MoO3 · H2O). The study also showed that understanding the stability and speciation of various soluble and solid Mo species are essential for the development of an efficient recovery process.