TUNGSTEN RECOVERY FROM TUNGSTEN ORE CONCENTRATES BY CAUSTIC DIGESTION

摘要

The tungsten is recovered from tungsten ore concentrates in the form of sodium tungstate by a basic process in which the ore is first digested in sodium hydroxide solution, followed by dilution of the solution sodium tungstate dissolved, separation of the solution of the caustic insoluble sludge and crystallization of soluble sodium tungstate, the present invention allows improved recovery of tungsten from difficult ore treated by the grinding process steps of ore concentrates tungsten particles having a size lower to about 200 gauge, addition ore triturated in aqueous sodium hydroxide solution at a temperature between about 10 and 30 C, dispersion of this ore triturated in aqueous hydroxide solution sodium before digestion, digestion at a temperature of 75 C and 150 C for a period of time sufficient to convert to nsiblement all amounts of tungsten to sodium tungstate soluble, and dissolving the mixture to reduce the concentration of sodium hydroxide between 4.5 and 5.5 molar at a temperature below about 90 C. to dissolve substantially all of the tungstate sodium.