CALCIUM PRODUCING METHOD AND APPARATUS (VERSIONS) Russian patent published in 2003 - IPC

FIELD: metallurgy. SUBSTANCE: method involves preparing basic mixture comprising calcium carbonate and aluminum powder; processing basic mixture under combined dissociation-reduction-melting mode carried out in three stages: at first stage basic mixture is vacuum heated at temperature of 700-850 C for 4-8 hours under residual gases pressure of 10-50 Pa, at second stage temperature of resultant mixture is increased also under vacuum condition and mixture is hold at residual pressure less than 10 Pa for 8-12 hours, at third stage resultant solid condensate is molten in argon under pressure of 15-25 kPa and at temperature of 900 C for 1-2 hours; discharging calcium into furnace well. According to first version, apparatus has furnace with at least one horizontal retort mounted inside furnace and equipped with heating zone and condensation zone. Retort is connected to vacuumizing system and to coolant circulation system. Discharge opening is formed in lower part of condensation zone and adapted for communicating said zone with metal collecting vessel. Electric heater is located inside condensation zone and at least one cylindrical basket for briquetted mixture is concentrically located inside heating zone. Cylindrical basket is provided with perforated cover. Perforated tube is mounted inside cylindrical basket and has diameter making 1/4 to 1/3 the diameter of retort. Tube axis is positioned higher than retort axis. Retort is connected to argon supply system. Size of perforations is less than size of mixture briquettes. According to second version, apparatus has furnace with at least one vertical retort. Condensation zone is equipped at its outside with detachable electric heater. Coolant circulation system is of open spraying type. Metal collecting vessel is mounted inside retort. Method and apparatus may be used for producing alkaline and alkaline-earth metal. EFFECT: increased efficiency, reduced power consumption provision for obtaining high-purity calcium in molten state, and reduced number of technological operations. 44 cl, 2 dwg, 1 tbl