METHOD FOR FORMING A TUNGSTEN POWDER HAVING A HIGH DEGREE OF PURITY FROM (5(NH4)2O 12WO3 5H2O) BY SELF-PROPARGATING HIGH-TEMPERATURE SYNTHESIS

摘要

PURPOSE: A method is provided to manufacture high purity tungsten (W) by leaching tungsten (W)-magnesium oxide (MgO) composite powder obtained as a byproduct of the reduction using about 20% hydrochloric acid (HCl) after reducing a raw material powder of ammonium paratungstate (5(NH4)2O·12WO3·5H2O) using magnesium (Mg) powder as a reductant in the self-propagating high temperature synthesis. CONSTITUTION: The method for manufacturing high purity tungsten powder comprises the steps of mixing ammonium paratungstate and magnesium in a mole ratio of 1:35; forming the formed mixture into a pellet by applying a forming pressure of 4 to 41 tons to the mixture; charging the pellet into a self-propagating high temperature synthesizing reactor under an inert gas atmosphere; burning the pellet in the self-propagating high temperature synthesizing reactor; discharging the manufactured burned product from the self-propagating high temperature synthesizing reactor; leaching the burned product using hydrochloric acid (HCl) which is diluted to 20%; filtering the leached exudation; and washing the filtered tungsten (W) powder.