GB552254A - Improvements in and relating to the refining of sublimable materials - Google Patents

Abstract

552,254. Magnesium ; sulphur; sublimation, apparatus for. MAGNESIUM METAL CORPORATION (American Magnesium Metals Corporation). June 20, 1941, Nos. 7819/41 and 9789/42. [Class 82 (i)] [Also in Group III] In a process and apparatus for refining sublimable materials, particularly magnesium, but applicable also to other materials, e.g. zinc, cadmium and sulphur, the speed of flow of vapour from the material to the condenser is controlled to prevent the carrying over of any impurities into the condensed product. In the case of magnesium, the speed may be not more than about 4.5 metres per second. The apparatus shown comprises a condenser C, which may be surrounded by a cooling coil 10, and a retort R mounted within an electrically heated chamber 4. The condenser and retort are arranged to be exhausted through a pipe 24, and the chamber 4 through a pipe 28, so that the walls 2 are not subjected to stresses. The material to be treated, which may be tablets or granules of magnesium dust with or without a binder, is charged through a central pipe 18 through the condenser into the retort where is occupies the space around a series of coaxial truncated conical members 22 which are surmounted by a perforated conical hood 23. The vapour evolved passes through the narrow spaces between the members 22 into the relatively larger central space where its speed is reduced, and thence through the hood 23 into the condenser, where it is deposited in solid form. The deposit may be received on a removable metal liner 8 which may be split to facilitate removal of the deposit or may be made of the material being sublimed, e.g. pure magnesium. In a modification, chains depend in the condenser near its walls and the body of condensed material embeds the chains and may be lifted out of the condenser which is of inverted conical form. Specification 381,115 and U.S.A. Specification 2,240,817 are referred to.