| 摘要 |
509,368. Chlorinating chromium ores; retorts; treating solids with gases. GREAT WESTERN ELECTRO-CHEMICAL CO. June 15, 1938, No. 17856. Convention date, June 15, 1937. [Classes 1 (i) and 1 (iii)] A chromite ore is finely divided and formed into a porous bed of less than 3 mm. thickness and chlorinated at a high temperature in the presence of a reducing agent with volatilization of its chromium, aluminium and iron contents. In carrying out the process a mixture of powdered ore, carbon and a binding agent such as water, tar or wax is agitated with carrier bodies of a comparatively inert material such as quartz mullite, coke or sintered ore, so that a film of ore from .25 mm. to .50 mm. thick is formed on the bodies. The coated bodies are continuously led down the shaft 6 of a vertical retort heated by electric resistances 8. Chlorine is led in by the pipe 12 and vapours are led off approximately a quarter of the way up the heated zone, into the condensing chamber 21. Scrapers 22 and 24 enable the condensate to be removed into the chamber 27, the gases being finally led through the cloth bag 29 to remove dust &c. which is dislodged from the material by periodic shaking. The chlorination is carried out at from 910‹-920‹C. with an excess of chlorine equal to 10-11 per cent. of the exit gases. Under these conditions aluminium iron and chromium are volatilized as chlorides, it being stated that the chromium forms a tetrachloride which is more volatile than chromic chloride and decomposes below 900‹C. Calcium and magnesium present form liquid chlorides which are absorbed by capillarity into the carrier bodies and thus are prevented from forming an impervious' layer over the unreacted ore. The carrier bodies finally pass out of the retort by the conveyer 18 and the calcium and magnesium chlorides and unreactive constituents are washed off. Alternatively the ash may be shaken off and the hygroscopic magnesium chloride serve to bind a fresh change of ore on to the bodies. The carrier bodies can vary from <3>/16 to ¥ inch in size according to the size of the retort. The carbon may be dispensed with and a mixture of hydrocarbon and chlorine or carbon tetrachloride may be used as the reagent gas. The Specification as open to inspection under Sect. 91 comprises also the modification of the process wherein other halogens may be used instead of chlorine. This subject-matter does not appear in the Specification as accepted. |
