GB919528A - Process for producing high purity rhenium and its compounds - Google Patents

Abstract

Per-rhenic acid, containing cationic metal contaminants is purified by contacting an aqueous solution thereof with a cation exchanger in the hydrogen form and recovering per-rhenic acid pure from the effluent, the cations being retained by the cation exchanger. Rhenium values are converted to per-rhenic acid by combustion in oxygen, condensing the oxides, mainly rhenium heptoxide, lixiviating said sublimate with distilled water, filtering and subjecting the filtrate to contact with a bed of cation exchanger. The effluent of purified per-rhenic acid may be neutralized with ammonia; ammonium per-rhenate may be crystallized and may be reduced by heating with hydrogen. The metal may be used for manufacturing electronic components by powder metallurgy. The mother liquor from which ammonium per-rhenate has been recovered may be recirculated in the process by adding it to a further batch of rhenium values. The cation exchanger may be regenerated by contact with a non-oxidizing mineral acid, e.g. 12% hydrochloric acid. The examples relate to the removal of impurities which include potassium, iron, copper, magnesium and aluminium ions; alkali and alkaline earth metal ions may also be removed by the process.