FORMING LOW-OXYGEN INGOT WITH HYDROGEN REDUCTION AND VACUUM MELTING OF METAL OXIDE, AND LOW-OXYGEN INGOT THEREOF

摘要

PURPOSE: A method of manufacturing low oxygen ingot is provided to manufacture low oxygen ingot with a small amount of oxygen by dehydrating molybdenum trioxide as a first step and vacuum melt the molybdenum trioxide as a second step. CONSTITUTION: A method of manufacturing low oxygen ingot comprises the following steps. Raw material metal oxide is put into a dehydrogenating apparatus and hydrogen gas is added to the apparatus. The raw material metal oxide is heated for a certain period of time to get metal oxide which is reduced. The reduced metal oxide is heated for a certain period of time to get metal oxide powder. The metal oxide powder is heated for a certain period of time to be removed from gas. The heated metal oxide powder is vacuum melted. The heating process for removing gas is carried out at a temperature of 1200-1500°C for 1-2 hours. The raw material metal oxide is molybdenum trioxide(MoO3), the reduced metal oxide is molybdenum dioxide(MoO2) and the reduced metal oxide poser is molybdenum(Mo). The vacuum melting is carried out under the atmosphere of inactive gas and H2 gas 5-20 % for 3-20 minutes. [Reference numerals] (ST100) Put molybdenum trioxide(MgO3) powder into a hydrogen reduction apparatus; (ST200) Enable H2 gas to flow into the hydrogen reduction apparatus(supplying flux: 1000-2000cc/min); (ST300) Heat molybdenum trioxide powder after reaching to a first reducing temperature(temperature: 500-600°C, maintaining time: 2 hour); (ST400) Heat molybdenum dioxide after reaching to a second reducing temperature(temperature: 800-1000°C, maintaining time: 1 hour); (ST500) Block H2 gas; (ST600) Degas and heat treat obtained metal molybdenum powder(heat treatment temperature: 1200-1500°C, maintaining time: 1 hour); (ST700) Put metal molybdenum powder into a vacuum dissolving furnace(vacuum dissolving atmosphere: Ar + 5% H2 gas); (ST800) Vacuum dissolve(vacuum dissolving time: 5-20 minutes); (ST900) Obtain molybdenum ingot