METHOD AND FURNACE FOR PROCESSING CHROMITE ORE INTO SODIUM CHROMATE Russian patent published in 1997 - IPC

FIELD: chemical engineering. SUBSTANCE: chromite ore is treated in soda ash or sodium hydroxide and sodium chromate melt at 1200 ± 50 C and chromite ore/alkali/sodium chromate molar ratio 1:1:(4-10). Oxygen-rich air is passed through reaction mass. Process is conducted in furnace having lined vertical casing 1 with bottom 2 and roof 4. The latter has loading port and gas flue fitting 6. Bottom 2 is made in the form of truncated cone accommodating discharge means in the form of drain hole 7 provided with cut-off means. Casing contains three graphite electrodes 8,9,10 and graphite air-distribution grate 11, under which blower 12 is installed to feed fresh oxygen-rich air onto grate from below. Electrode 8 is made as hollow cylinder coaxially disposed inside furnace and tightly adjoining wall of lining 3. Electrode 9 is a rod disposed in the center of furnace and supported by air-distribution grate 11. Electrode 10 is a bottom insertion-bushing located in drain hole 7 of bottom 2. Each electrode has current-supply bus 13 conducting one phase of alternating current, cylinder 8 and bushing 10 having the same phase. EFFECT: enhanced efficiency of process. 2 cl, 2 dwg