Patent EP-0091414-A1 (EP)
Inventor: ISHIZUKA HIROSHI
IPC: C22B34/12
Filed: 1983-03-29
Abstract: An apparatus and method for production of refractory metal from a chloride thereof, comprising a conversion assembly (Figure 1) and a purification assembly (Figure 2) the former in turn comprising: an elongated vertical cylindrical member (2) with an open top and a closed bottom, another cylindrical member (5) open at each end but having a grid plate (6) detachably supported at a bottom thereof, said cylindrical members consisting of axially arranged outer (2) and inner (5) vessels, respectively, an annular top cover (8) joined on respective upper ends of said outer and inner vessels, a closure (12) joined over a central bore of said top cover (8), a furnace means (3) surrounding said outer vessel (2), a tube means (7) which extends through the closure (12) into the inner vessel (5) for feeding raw chloride, another tube means (7) which opens in the outervessel (2) at a bottom thereof and extends along a wall thereof outwards for discharging fluids, and a means for evacuation (15) and introduction (16) of inert gas; while the purification assembly (21) comprisng: an elongated vertical cylindrical retort (22) which is separable into a coolable upper half (22a) and a heatable lower half (22b), a cylindrical member open at each end thereof to consist another inner vessel (27) coaxially arranged inside the retort (22), another top cover (28) joined on respective upper ends of the retort (22) and inner vessel (27) another closure (30a) joined over a central bore of the top cover, a furnace means (25) surrounding the retort lower half (22b), a water jacket (26) on the retort upper half (22a), and a duct means (30) connected with the closure (30a) for degassing the retort, said inner vessels (23, 27) being of a common construction to each other, and the top cover (28) of the purification assembly, as well as the closure (30a), being secured airtightly but detachably to the retort (22) and the inner vessel (27) by a mechanical means adaptable to secure the top cover and closure to the outer and inner vessels of the conversion assembly, respectively. 
     Such apparatus is most effectively operated in the following way: providing a conversion assembly such as specified above, holding fused magnesium at a level above the grid plate, feeding raw chloride to the magnesium, thus initiating a reaction therebetween to form a refractory metal product and magnesium chloride byproduct, depositing said product in an inner vessel (5), discharging the byproduct for some part in liquid state so that magnesium overlying the byproduct may exhibit a lowered level, discontinuing supply of the raw chloride to terminate the conversion step at a timing where the magnesium remains unconsumed for some part, cooling and removing the inner vessel (5) with a mixed mass of product, byproduct and magnesium loaded and the top cover joined thereto, providing a purification assembly such as specificed above but with the retort upper half removed, placing the inner vessel (5) in the retort lower portion to become the lower inner vessel (23) of the assembly, removing the top cover from said vessel (23), putting on the retort upper half (22a), another inner vessel (27), a top cover (28) and a closure (30a) with a duct means (30), all assembled in advance, over the lower half (22b) of the retort (22), degassing said retort to an elevated vacuum, providing such a temperture condition in the retort that magnesium chloride and magnesium metal evaporate to ascend from the vessel (23) and deposit on the inner vessel (27) upwards, taking out said vessel (27) from the retort with the top cover secured thereto, joining the vessel (27) with the outer vessel (22), top cover (28), closure (30a), and grid plate (6) to set up the conversion assembly, replenishing fused magnesium to a level above the grid plate, and resuming the conversion run, while refractory metal product is recovered from the inner vessel (27) with a pressing mechanism after the vessel (27) has been taken from the purification retort.