GB759724A - Improvements in and relating to the making of zirconium chloride - Google Patents

Abstract

<PICT:0759724/III/1> Zirconium chloride is prepared by fluidizing a mass of a zirconium ore, preferably zircon, in the presence of carbon with gaseous chlorine at a temperature such that chlorination occurs, suitably between 800 DEG and 1100 DEG C and condensing the chloride formed from the gaseous reaction product. When zircon is employed a 4:1 by weight ratio of zircon to carbon is preferred but greater amounts of carbon may be employed if an oxygen containing gas is fed to the reaction chamber to supply heat by carbon combustion. The reaction zone may be indirectly heated for example by an electric furnace or the mixture of oil and carbon or the chlorine gas may be preheated. In the drawings, Fig. 2, a fluidized mass of zircon and carbon is maintained in a silica reaction tube 5 by feeding the ore/carbon mixture through hopper 40 and fluidizing the bed by chlorine gas fed through line 28 from a source 32. The centre part of the reaction zone is surrounded by an electric furnace 6 containing silicon carbide resistance heating elements 9. Gaseous reaction products leave the furnace through an arm 44 which is surrounded by a packed ceramic fibre layer 48 in which is embedded a heating coil 50 to maintain the arm 44 at 325 DEG to 350 DEG C. The reaction products pass into condenser 4 where zirconium chloride precipitates, deposition on the walls being prevented by a vibrator 58; uncondensed reaction products pass through line 55 to a further condenser 62 where silicon tetrachloride is precipitated. In operation, before the passage of chlorine gas, the apparatus is swept by a nitrogen stream fed from a container 31 and the thus fluidized mass of zircon and carbon is heated to about 1000 DEG C before the nitrogen is replaced by chlorine from source 32. The feed line 39 from the hopper 40 is heated by means not shown, to prevent clogging of the line by deposition of sublimed zirconium chloride. At the close of the operation the chlorine stream is substituted by nitrogen and the electric furnace removed. When the temperature has dropped to about 300 DEG to 400 DEG C the nitrogen is turned off and the condensers 4 and 62 are removed and replaced by a calcium chloride drying tube to prevent moisture being drawn into the system as it cools. The process is applicable to other zirconium ores such as zirkite or baddeleyite.