Abstract Rhenium, a by-product of molybdenum's extractive metallurgy, can be recovered from acidic gas-scrubbing solutions by using the techniques of direct precipitation and separation on resin. Direct precipitation is achieved by using tetraphenylphosphonium bromide (φ4P). This technique yields an organometallic precipitate containing more than 25% Re and less than 1% Mo and Se. The reaction is fast and selective, with a stoichiometry φ4P/Re = 1/1. Separation on resins is achieved with a weak base anionic resin of the tertiary amine type. By using the reflux method, the weakly coadsorbed molybdenum and selenium are removed by a concentrated sulfuric acid solution containing rhenium. Rhenium is then selectively eluted by an ammoniacal solution from which pure ammonium perrhenate is crystallized.