US2186447A - Method of making molybdenum and alloys of molybdenum - Google Patents

Description

Patented Jan. 9, 1940 METHOD OF MAKING MOLYBDENUM AND 'ALLOYS OF MOLYBDENUM Joseph 11. Brennan, Niagara Falls, N. Y., assignor to Electro Metallurgical Company, a corporation of West Virginia No Drawing. Application January 28, 1939, Serial No. 253,449

4 Claims. (01. 75-176) The principal ores of molybdenum, including the sulfide ore, molybdenite, very often contain substantial amounts of copper minerals, for

instance copper sulfide, which can not readily be separated from the ore by mechanical methods.

Inasmuch as there is a demand for metallic molybdenum andmolybdenum alloys containing one or more metals of the iron group (iron, cobalt, nickel) with little or no copper, a practical m method is needed for producing these alloys from copper-contaminated molybdenite, roasted molybdenite, or other molybdenum sources. It is an object of this invention to provide such a process. 5 In accordance with the invention, molybdenite,

roasted molybdenite, or other ore source of molybdenum, contaminated with copper mineral,

30 may be used. A moderate excess of reducing agent is desirable, but a large excess should be avoided.

Soda ash is a satisfactory form of basis flux for use in this process. The sodium carbonate is 35 believed to enter into a chemical reaction of the type:

2NazCOs+MoS2+2C=2Na;S+2COz+2CO+Mo thereby supplying sodium sulfide to the slag. A

40 substantial excess of sodium carbonate may be used. Lime, limestone, magnesia, or dolomite may be added to supplement the action of sodium carbonate by reactions of the type:

and to aid in fiuxing gangue materials, silicate for instance. Other basic, or neutral, fiuxing agents may be added if desired. Preferably, a

rather large excess of basic fluxes is added to 50 keep the slag basic. It is preferred, furthermore,

that sodium be the predominating base-forming element of the slag.

As indicated above, the sodium sulfide may be formed by reaction of soda ash with carbon and the sulfides in the ore. Altemately or additionally, sodium sulfide may be added to the slag; or sodium sulfate and a reducing agent; or calcium sulfate, a reducing agent, and a sodium compound such as soda ash. The latter methods are particularly useful in the treatment of oxidized ores of molybdenum.

The molybdenite material to be treated will ordinarily contain between 25% and 60% molybdenum and 1% to 15% copper.

The following specific examples of processes embodying the principles of the invention serve to illustrate such principles, but it-will be understood that the scope of the invention is not limited to or by these examples.

Example I 100 parts of a molybdenite concentrate containing 34.2% M0, 3.5% Fe, 1.5% Cu, 25% S, remainder chiefly gangue, was mixed with 100 parts of soda ash, 50 parts of lime, 29 parts of iron (nail scrap), and 27 parts of bituminous coal. The mixture was melted in an open-arc electric furnace, the reactions completed, the slag removed, and the alloycast. The cast alloy contained 53.2% M0, 1.6% C, 0.13% Cu, 0.24% S, remainder iron. Thus, the ratio of Mo to Cu of about'22 in the ore was raised to about 400 in the alloy. The slag contained 2.98% Mo and 0.45% Cu. 7

Example I! I ,3

100 parts of molybdenite concentrates containing 28.2% Mo, 10.9% Cu, 10.9% Fe, 31.0% S, remainder chiefly gangue (ratio of Mo to Cu about 2.6) was mixed with '72 parts of soda ash, 65

parts of lime, 10 parts of iron (nail scrap), and 25 parts of bituminous coal. The mixture was melted and treated as in Example I. .The resulting alloy contained 69.6% Mo, 27.4% Fe, 1.4% Cu, 0.19% C, and less than 0.08% S (a ratio of Mo to Cu of about49). The slag contained about 5% each of molybdenum and copper.

Example In 100 parts of the same concentrate as that used in Example 11 was mixed with '75 parts of soda ash, 65 parts of lime, 13 parts of iron (nail scrap),

other than sodium carbonate may be used, and heating means other than an open-arc electric furnace may be utilized. However, the preferred procedure is that specifically described herein.

I claim:

1. Method of treating crude material containing reducible compounds of molybdenum and copper to produce a molybdenum alloy in which the ratio of molybdenum to copper is higher than in said crude material, which includes the step of reducing said compounds in the presence of a basic flux essentially containing sodium sulfide.

2. Method of making, from molybdenite material containing a substantial proportion of copper as copper sulfide, a molybdenum alloy in which the ratio of molybdenum to copper is higher than in said molybdenite material, which comprises reducing said molybdenite material in the presence of a basic slag essentially containing sodium sulfide.

3. Method of making, from molybdenite material containing a substantial proportion of copper sulfide, molybdenum alloys in which the ratio of molybdenum to copper is higher than in said molybdenite material, which comprises heating at a reaction temperature a mixture including said molybdenite material, coal, soda ash, and lime, and coalescing the resulting metallic molybdenum with molten metal of the iron group.

4. Method which comprises melting in an electric furnace a mixture consisting of the following ingredients in approximately the proportions indicated: molybdenite containing 25% to 60% molybdenum and about 1% to copper, 100 parts; bituminous coal, to parts; soda ash, 70 to 100 parts; lime, to parts; iron, 10 to 30 parts; and separating the resultinglow-copper alloy and high-copper slag.

JOSEPH H. BRENNAN.