Studies on Reduction of Ammonium Paratungstate for producing the Tungsten Powder

Abstract

India is entirely dependent on the imports of tungsten bearing materials e.g. tungsten powder, tungstic acid, etc, generating considerable quantity of tungsten-copper (W-Cu) alloy scraps. NML has developed a novel process of direct leaching of W-Cu borings, a waste product from the M/s Miapalloy, Chennai in the ammonium solution, separat-ing the dissolved copper by the solvent LIX 84 (2-(N-Hydroxyethanimidoyl)-4- nonylphenol C17H27NO2) and then crystallising the separated ammonium paratungstate solut-ion as ammonium paratungstate (APT). In the present work a detailed investigation on the reduction of APT having purity of 99.95 was used as the starting material to pro-duce the tungsten powder. In the present investigations were conducted on the effect of temperature at different time intervals, effect of flow rate of hydrogen gas, effect of time and evaluation of kinetics at various temperatures of hydrogen gas. Under the optimised conditions, the amount of hydrogen gas required at diff-erent quantity of APT used was also reported.