METHOD FOR ALUMINOTHERMIC PRODUCTION OF METALLIC CHROME Russian patent published in 2011 - IPC C22B34/32 C22B5/04 

FIELD: metallurgy.

SUBSTANCE: preparation, loading and burning of charge is performed; the above charge contains chromic anhydride and sodium or potassium bichromate in ratio of 1.3:1.7 at the following component ratio of charge, wt %: chrome oxide - 57.5-61.0, aluminium - 24.5-26.9, chromic anhydride - 4.9-6.9, sodium or potassium bichromate - 3.7-4.6, calcium hydroxide - 1.2-1.6, sodium chloride - 0.5-0.7, lime with carbon content of not more than 0.2 wt % - 2.3-2.5, fluorspar concentrate - 0.5-1.0 to weight of chrome oxide. Lime with carbon content of not more than 0.2 wt % is introduced immediately to charge, and lime with carbon content of not more than 0.5 wt % is loaded to the stock 2-4 minutes before the end of the charge burning at the ratio of lime with carbon content of not more than 0.2 wt % and lime with carbon content of not more than 0.5 %, which equals to (50-70):(30-50) respectively. At that, loading and burning of charge is performed in one stage with speed of 330-450 kg/m² min, and after some portion of slag is drained to the casting form on slag lining, fluorspar concentrate is loaded on the rest of liquid slag, and after the latter is dissolved, slag and metal is drained.

EFFECT: increasing the output of high-quality grades of chrome, increasing the extraction property of chrome to metal.

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