Ammonium Paratungstate One Step Reduction Producing Tungsten Powder
Ammonium paratungstate calcinates into yellow tungsten oxide or blue tungsten oxide under mild reduction atmosphere, and then producing tungsten powder by hydrogen reduction. It is the most widely applied in industry at present. However, this method takes longer process, impurities can enter easily and relative high manufacture cost. As a result, using ammonium paratungstate as raw material to produce tungsten powder which is of high quality, also shorten process and lower cost.
1.Weigh a certain amount of APT into railboat, then put into hydrogen reduction furnace, inlet nitrogen for 20min, charge and set temperature rising procedure, then inlet hydrogen and nitrogen mixing gas by a certain ratio, atmosphere in furnace keeps stay in mild reduction status.
2.When temperature rises to a certain degree, keep it warm to eliminate moisture and ammonia gas in APT, then keep increasing temperature to the needed degree for hydrogen reduction, inject hydrogen and process the second period of hydrogen reduction. After reduction is completed, turn off the hydrogen valve and turn on nitrogen to cool it down to a certain temperature and take it out.