Patent GB-484329-A (GB)
Title: Improvements in or relating to processes for the manufacture of tungsten from its ores, salts or other compounds of tungsten
IPC: C22B34/36
Filed: 1936-12-21
Abstract: Tungsten is produced by first forming tungsten sulphide by heating a tungsten ore or compound with a carbonaceous material such as powdered coal, low temperature carbonization coke, brown coal or charcoal in sulphur vapours and/or a gaseous non-metallic sulphur compound, e.g. carbon bisulphide or sulphuretted hydrogen, to say about 800-1200 DEG  C. and thereafter reducing the tungsten sulphide by heating it with a metal, e.g. aluminium, calcium, barium, sodium or magnesium, the heat of formation of the sulphide of which is greater than that of tungsten sulphide, this operation being effected in an atmosphere of a reducing and/or inert gas and in the substantial absence of moisture, nitrogen, oxygen or oxygen-containing gas, e.g. in an atmosphere of hydrogen or argon. Pure tungsten salts or other compounds may be employed as initial materials.  In examples, (1) tungsten trioxide, mixed with about an equal weight of low temperature carbonization coke, is heated at about 950 DEG  C. while sulphur vapours are passed through the mixture.  The carbon monoxide produced can be used for heating or any other purpose.  The tungsten sulphide produced is mixed with aluminium chips or powder and heated in a current of hydrogen or argon, the temperature being preferably kept below the melting point (about 1100 DEG  C.) of p  the aluminium sulphide formed; (2) wolframite is crushed and mixed with an equal quantity of low temperature carbonization coke, and heated in sulphur vapours at about 950 DEG  C.  The mixture of tungsten, iron and manganese sulphides formed is reduced with calcium or aluminium as in example (1).  The aluminium or calcium sulphide formed is separated, and treated for the recovery of the sulphur content, which may be re-employed in the process.  The iron and manganese may be separated from the tungsten by dissolving them, e.g. with hydrochloric acid of sp. gr. 1,12 or 1,19.  In both of the examples, the quantity of aluminium or calcium used is about 10 per cent over that theoretically required.  Another suitable tungsten containing ore is scheelite.ALSO:Tungsten is produced by first forming tungsten sulphide from a tungsten ore or compound, and thereafter reducing the tungsten sulphide by heating it with a metal, e.g. aluminium, calcium, barium, sodium, or magnesium, the heat of formation of the sulphide of which is greater than that of tungsten sulphide, this operation being effected in an atmosphere of a reducing and/or inert gas and in the substantial absence of moisture, nitrogen, oxygen, or oxygen-containing gas, e.g. in an atmosphere of hydrogen or argon. Pure tungsten salts or other compounds may be employed as initial materials whereby pure tungsten is obtained directly.  In examples, (1) tungsten trioxide is converted into tungsten sulphide, which is mixed with aluminium chips or powder and heated in a current of hydrogen or argon, the temperature being preferably kept below the melting point (about 1100 DEG  C.) of the aluminium sulphide formed; (2) wolframite is treated for the production of a mixture of tungsten, iron, and manganese sulphides and the mixture is reduced with calcium or aluminium as in example (1).  The aluminium or calcium sulphide formed is removed, and the iron and manganese may be separated from the tungsten by dissolving them, e.g. with hydrochloric acid of sp. gr. 1,12 or 1,19.  In both of the examples, the quantity of aluminium or calcium used is about 10 per cent over that theoretically required.  Another suitable tungsten-containing ore is scheelite.