US1437271A - Manufacture of ferrotungsten - Google Patents

Description

.155 Church Road, Battersea, London,

Patented Nov. 28, 1922.

UNITED STATES JOHN MUBDOCH SKELLEY AND JAMES MERSON, OF BATTERSEA, LONDON, ENGLAND,

PATENT OFFICE.

ASSIGNOBS TO CONTINUOUS REACTION COMPANY, LIMITED, OF LONDON, ENGLAND.

MANUFACTURE OF FERROTUNGSTEN.

Io Drawing.

To all whom it ma concem:

Be it known that we, JoHN MURDOOH,

SKELLEY and JAMES MnRsoN, both subjects of the King of Great Britain, residin at n land, have invented new and useful Iniprovements in the Manufacture of Ferrotungsten, of which the following is a specification.

-This invention relates to improvements in the manufacture of ferrotungsten, i. e. alloys of tungsten and iron in various proportions, containing up to about ;85 per cent of tungsten respective These alloys have itherto been manufactured as a rule .from ores or mixtures containing iron an tungsten by reduction either in the electric furnace or by the alumino-thermic process. In some cases the alumino-thermic reduction has been effected by means of a mixture of aluminium and ferrosilicon, but it has not been possible to dispense with the use'of a substantial proportion of aluminium, which is a relatively costly reducing agent.

The present invention is based upon the discovery that if ores or mixtures containing iron and tungsten in the form of oxides be mixed with pulverized silicon or ferrosilicon and a suitable oxidizing agent containing nitrogen such as sodium nitrate, but without aluminium, reaction may be initiated at a point in a cold or heated mixture as in the alumino-thermic process, and if suitable proportions of the ingredients be used the reaction proceeds to completion,

ferrotungsten practically free from carbon and silicon resultin According to th1s invention, therefore, ferrotungsten is produced without the aid 'of aluminium by the silico-thermic reduction of a mixture of oxide ofiron with oxide of tungsten, or of an ore containing iron nitrate.

As a rule, the richer the reducing agent is in silicon, the better is the reaction. Commercial silicon, which contains up to about 95% Si, or ferrosilicon containingfrom 90 to 70% Si, can be used with excellent results. It will be understood that with ferro- Application filed. Kay 29,

silicon containing lower proportions of silicon the reaction becomes more sluggish and The following example illustrates the.

invention A commercial tungsten ore is subjected to a preliminary purification to remove any tin and other undesired constituents present and is then roasted till free from sulphur.

Of the product, containing per cent of- WO,, 16 per cent of FeO and 8 per cent of Mn(), 100 lbs; are mixed with 20% lbs. of ferrosilicon (90% Si) and 5 lbs. of sodium nitrate. Preferably 5 lbs. of calcium fluoride are added to enhance the fluidity of the slag. The mixture is put into a crucible and reaction is initiated as in the aluminothermic process. 1

What we claim is 1. The manufacture: of ferrot ungsten without the aid of aliminium by the sllicothermic reduction of iron oxide and tungsten oxide in the presence of an oxidizing agent containing nitrogen.

2. The manufacture of ferrotungsten without the aid of aluminium by' the silico-- thermic reduction of iron oxide andtungsten oxide in the presence of sodium nitrate.

3. The manufacture of ferrotungsten by purifying tungsten ore to remove any tin and other undesired constituents present, roasting the residue to remove sulphur, mixing with the product ferrosilicon and an oxidizing agent containing nitrogen, and producing reaction as in the we known alumino-thermic process.

- 4. The manufacture of ferrotungsten without the aid of aluminum by the sllicothermic reduction of iron oxide and tungsten oxide in the presence of a nitrate oxidizing agent.

' 5. The manufacture of ferrotungsten by purifying tungsten ore to remove any tin and other undesired constituents pres ent, roasting the residue to remove sulphur, mixing with the product ferrosilicon and a nitrate oxidizing agent, and producing reaction as in the Well known alumino-thermic oxide, 8 parts of manganese oxide, 20% parts of ferrosilicon and 5 parts of sodium nitrate. 10

In testimony that We claim the foregoing as our invention We have signed our names this 17th day of May, 1922.

JOHN MURDOCH SKELLEY. JAMES MERSON.