Production of high-purity molybdenum compounds from a Cu–Mo acid-washed liquor using solvent extraction. Part 2: Pilot and plant operations

Laboratory studies on the recovery of molybdenum from acid wash liquor, reported in Part 1 of this series of papers, identified the optimum process conditions for the production of high purity molybdenum trioxide and calcium molybdate. Pilot and plant scale operations were conducted as a result of the design developed during our laboratory studies.Molybdenum was selectively recovered from a wash liquor containing 10 g/L Mo via a 2-stage extraction using 10% v/v Alamine diluted in Anysol 150 diluent as extractant. The use of 10% v/v isodecanol (IDA) was found to enhance the extraction of molybdate from the wash liquor. The organic extractant liquor had to be scrubbed with water to remove the ammonium sulphate crud formed when ammonium hydroxide solution (20% w/v) was used to strip the molybdate from the loaded organic. The pilot scale study (0.2 m3/day) and plant operation (30 m3/day) were able to be continuously operated to recover 99% Mo from the wash liquor, from which high purity MoO3 and CaMoO4 of >99.9% purity could be recovered.