| abstract |
A method of preparing primary refractory metais (e.g., primary tantalum metal) by contacting a particulate refractory metal oxide (e.g., tantalum pentoxide) with a heated gas (e.g., a plasma), is described. The heated gas comprises hydrogen gas. The temperature range of the heated gas and the mass ratio of hydrogen gas to refractory metal oxide are each selected such that: (i) the heated gas comprises atomic hydrogen; (ii) the refractory metal oxide feed material is substantially thermodynamically stabilized (i.e., the concurrent formation of suboxides that are not reduced by atomic hydrogen is minimized); and (iii) the refractory metal oxide is reduced by contact with the heated gas, thereby forming primary refractory metal (e.g., primary tantalum metal and/or primary niobium metal). |