US2913315A - Tungsten carbide purification - Google Patents
Tungsten carbide purification Download PDFInfo
- Publication number
- US2913315A US2913315A US642667A US64266757A US2913315A US 2913315 A US2913315 A US 2913315A US 642667 A US642667 A US 642667A US 64266757 A US64266757 A US 64266757A US 2913315 A US2913315 A US 2913315A
- Authority
- US
- United States
- Prior art keywords
- tungsten carbide
- pyrosulfate
- molten
- carbide
- salt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 title claims description 28
- 238000000746 purification Methods 0.000 title description 3
- 238000000034 method Methods 0.000 claims description 19
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 13
- 150000002739 metals Chemical class 0.000 claims description 12
- 150000003839 salts Chemical class 0.000 claims description 12
- 229910052783 alkali metal Inorganic materials 0.000 claims description 6
- 150000001340 alkali metals Chemical class 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 4
- 230000004927 fusion Effects 0.000 claims description 3
- VFNGKCDDZUSWLR-UHFFFAOYSA-L disulfate(2-) Chemical compound [O-]S(=O)(=O)OS([O-])(=O)=O VFNGKCDDZUSWLR-UHFFFAOYSA-L 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 229910052742 iron Inorganic materials 0.000 description 7
- KAQHZJVQFBJKCK-UHFFFAOYSA-L potassium pyrosulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OS([O-])(=O)=O KAQHZJVQFBJKCK-UHFFFAOYSA-L 0.000 description 7
- 239000002253 acid Substances 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- -1 tungsten carbides Chemical class 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- 239000000908 ammonium hydroxide Substances 0.000 description 3
- 239000002585 base Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000011876 fused mixture Substances 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- 229910021654 trace metal Inorganic materials 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 229910001930 tungsten oxide Inorganic materials 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 235000010678 Paulownia tomentosa Nutrition 0.000 description 1
- 240000002834 Paulownia tomentosa Species 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 239000003637 basic solution Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-M bisulphate group Chemical class S([O-])(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-M 0.000 description 1
- 239000002802 bituminous coal Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- NNIPDXPTJYIMKW-UHFFFAOYSA-N iron tin Chemical compound [Fe].[Sn] NNIPDXPTJYIMKW-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- CHKVPAROMQMJNQ-UHFFFAOYSA-M potassium bisulfate Chemical compound [K+].OS([O-])(=O)=O CHKVPAROMQMJNQ-UHFFFAOYSA-M 0.000 description 1
- 229910000343 potassium bisulfate Inorganic materials 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- JXAZAUKOWVKTLO-UHFFFAOYSA-L sodium pyrosulfate Chemical compound [Na+].[Na+].[O-]S(=O)(=O)OS([O-])(=O)=O JXAZAUKOWVKTLO-UHFFFAOYSA-L 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 238000004846 x-ray emission Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/949—Tungsten or molybdenum carbides
Definitions
- This invention relates to reducing the trace metal content of tungsten carbide. More particularly, this invention relates to a refining process for reducing the trace metal content, such as iron and manganese, of tungsten carbide which comprises heating a mixture of tungsten carbide and an alkali metal pyrosulfate salt to a temperature where the salt component is molten.
- Tungsten carbide is an extremely important article of commerce, useful in applications requiring high temperatures, hardness and/or high wear resistance. It is the most important constituent of modern cemented carbides. Sintered or fused tungsten carbides are employed in applications requiring high wear resistance.
- Tungsten carbide is well known and can be prepared, for example, by those methods described in Refractory Hard Metals by Schwarzkoff et al., pp. 138-161 (Mac- Millan Co., 1953).
- tungsten carbide produced by these methods does not always meet specifications as to trace metals, for example, iron and manganese, present in the final product.
- tungsten carbide is prepared by the method of Li and Dice, described in US.
- Patent 2,535,217 wherein the carbide is produced directly from ore containing tungsten oxide by reduction with carbon, such as bituminous coal, in the presence of iron-tin alloys at temperatures as low at 1420 C., there is obtained a product containing iron and manganese in the order of about 1 or more percent.
- These trace metals which tend to soften the carbide, cannot be removed even when tungsten carbide is treated with strong acids under conditions at which chemical attack of the tungsten carbide itself is observed. Thus, it appears that these trace metals are trapped in the carbide in such a manner that is resistant tochemical attack.
- the amount of trace metals, such as iron and manganese, present in tungsten carbide can be reduced, for example, to 20-30% of their original content by a process which comprises heating a mixture of tungsten carbide and a pyrosulfate salt, for example, an alkali metal pyrosulfate, to a temperature where the salt is molten;
- a pyrosulfate salt for example, an alkali metal pyrosulfate
- the reaction is carried out by heating a mixture of tungsten carbide particles and an alkali metal pyrosulfate, for example, potassium pyrosulfate, for minutes to two hours or longer, but preferably from 10 to 20 minutes, at a temperature where the pyrosulfate component is molten, cooling, and then extracting the fused mixture with water- Further purification can be effected by washing with a basic solution, such as ammonium hydroxide, and subsequently washing with a dilute acid, suchas hydrochloric acid, followed by a water wash.
- a basic solution such as ammonium hydroxide
- the ratio of tungsten carbide to the pyrosulfate salt is not critical provided there is sutlicient pyrosulfate salt to stoichiometrically react with the trace metals present in the carbide.
- the temperature of the reaction mixture is not critical provided the reaction mixture is fused, in practice I have employed temperatures of from 300 to 500 C. or higher, preferably about 350 C.
- ingredients may be added which are capable of forming pyrosulfates in situ.
- potassium hydrogen sulfate or potassium sulfate moistened with sulfuric acid mixed with tungsten carbide forms potassium pyrosulfate in situ during heating.
- an excess of the sulfate, bisulfate salt or sulfuric acid lowers the melting of the fused mixture so that mixtures employed in the process can be fused below the melting point of potassium pyrosulfate itself, for example, below 300 C.
- the following examples illustrate the reduction of the iron and manganese content of tungsten carbide.
- 2 parts of potassium pyrosulfate (Kgsgoq) and 1 part of tungsten carbide particles were intimately mixed and heated as shown in Table I.
- the resulting melts had cooled to room temperature, they were dissolved in water and treated with concentrated ammonium hydroxide.
- the resulting tungsten carbide crystals were then separated by filtration, and washed with dilute hydrochloric acid and water.
- the starting materials and products were analyzed for iron and manganese by X-ray emission spectroscopy. These results are presented in Table I.
- the products of this invention are useful in these applications for which tungsten carbide is now presently used, taking into consideration that the reduction of the iron and manganese content produces a harder material.
- the product of my invention can be used in tools, crucibles, machinery, drilling apparatus and other applications which demand refractory properties, hardnessand/or high wear resistance.
- a process for removing from impure tungsten carbide particles, the trace metals which react with molten alkali metal pyrosulfates which comprises contacting the impure tungstencar'b'idewith a molten alkali metal pyrosulfate, thereb-y extracting thetrace metals 'in'tothe molten salt and thereafter separating the purified tungsten c'arbide from the fusion mass.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Carbon And Carbon Compounds (AREA)
Description
United States Patent TUNGSTEN CARBIDE PURIFICATION William W. Welbon, Ballston Lake, N.Y., assignor to General Electric Company, a corporation of New York No Drawing. Application February 27, 1957 Serial No. 642,667
9 Claims. (Cl. 23-208) This invention relates to reducing the trace metal content of tungsten carbide. More particularly, this invention relates to a refining process for reducing the trace metal content, such as iron and manganese, of tungsten carbide which comprises heating a mixture of tungsten carbide and an alkali metal pyrosulfate salt to a temperature where the salt component is molten.
Tungsten carbide is an extremely important article of commerce, useful in applications requiring high temperatures, hardness and/or high wear resistance. It is the most important constituent of modern cemented carbides. Sintered or fused tungsten carbides are employed in applications requiring high wear resistance.
Tungsten carbide is well known and can be prepared, for example, by those methods described in Refractory Hard Metals by Schwarzkoff et al., pp. 138-161 (Mac- Millan Co., 1953). However, tungsten carbide produced by these methods does not always meet specifications as to trace metals, for example, iron and manganese, present in the final product. Thus, where tungsten carbide is prepared by the method of Li and Dice, described in US. Patent 2,535,217, wherein the carbide is produced directly from ore containing tungsten oxide by reduction with carbon, such as bituminous coal, in the presence of iron-tin alloys at temperatures as low at 1420 C., there is obtained a product containing iron and manganese in the order of about 1 or more percent. These trace metals, which tend to soften the carbide, cannot be removed even when tungsten carbide is treated with strong acids under conditions at which chemical attack of the tungsten carbide itself is observed. Thus, it appears that these trace metals are trapped in the carbide in such a manner that is resistant tochemical attack.
Unexpectedly, I have now discovered that the amount of trace metals, such as iron and manganese, present in tungsten carbide can be reduced, for example, to 20-30% of their original content by a process which comprises heating a mixture of tungsten carbide and a pyrosulfate salt, for example, an alkali metal pyrosulfate, to a temperature where the salt is molten; The unexpectedness of this process is enhanced by the fact that removal is effected by this process whereas strong acid extractions fail under extreme reaction conditions.
The mechanism of the reaction is not understood since if the trace metals were on the surface of the crystals of carbide, one would expect them to be removed by acids. Since this is not the case, the trace metals are probably trapped in the interior of the crystals. On the other hand, if this is true, it is ditficult to conceive of a mechanism whereby reaction with a pyrosulfate salt should succeed where strong acid treatment fails.
In general, the reaction is carried out by heating a mixture of tungsten carbide particles and an alkali metal pyrosulfate, for example, potassium pyrosulfate, for minutes to two hours or longer, but preferably from 10 to 20 minutes, at a temperature where the pyrosulfate component is molten, cooling, and then extracting the fused mixture with water- Further purification can be effected by washing with a basic solution, such as ammonium hydroxide, and subsequently washing with a dilute acid, suchas hydrochloric acid, followed by a water wash.
The ratio of tungsten carbide to the pyrosulfate salt is not critical provided there is sutlicient pyrosulfate salt to stoichiometrically react with the trace metals present in the carbide. There is no upper limit to the amount of pyrosulfate required except that based on practical considerations. In practice, I have employed 1-20 parts or more of potassium pyrosulfate for each part by weight of carbide. Although the temperature of the reaction mixture is not critical provided the reaction mixture is fused, in practice I have employed temperatures of from 300 to 500 C. or higher, preferably about 350 C.
In addition to adding pyrosulfates to tungsten carbide, ingredients may be added which are capable of forming pyrosulfates in situ. Thus, potassium hydrogen sulfate or potassium sulfate moistened with sulfuric acid mixed with tungsten carbide forms potassium pyrosulfate in situ during heating. In addition an excess of the sulfate, bisulfate salt or sulfuric acid lowers the melting of the fused mixture so that mixtures employed in the process can be fused below the melting point of potassium pyrosulfate itself, for example, below 300 C.
The following examples are illustrative of the practice of my invention and are not intended for purposes of limitation. In the examples, all parts are by weight unless otherwise stated.
The following examples illustrate the reduction of the iron and manganese content of tungsten carbide. In the following example, 2 parts of potassium pyrosulfate (Kgsgoq) and 1 part of tungsten carbide particles were intimately mixed and heated as shown in Table I. When the resulting melts had cooled to room temperature, they were dissolved in water and treated with concentrated ammonium hydroxide. The resulting tungsten carbide crystals were then separated by filtration, and washed with dilute hydrochloric acid and water. The starting materials and products were analyzed for iron and manganese by X-ray emission spectroscopy. These results are presented in Table I.
Although the foregoing examples have described a few variations and modifications of ingredients and reaction conditions which may be employed in the practice of the present invention, it should be understood that my process is also applicable to other reaction conditions, and proportions of ingredients which are not specifically illustrated by the examples. For example, other fusable pyrosulfate salts, such as sodium pyrosulfate, etc., can also be employed.
The products of this invention are useful in these applications for which tungsten carbide is now presently used, taking into consideration that the reduction of the iron and manganese content produces a harder material. Thus, the product of my invention can be used in tools, crucibles, machinery, drilling apparatus and other applications which demand refractory properties, hardnessand/or high wear resistance.
What I claim as new and desire to secure by Letters Patent of the United States is:
l. A process for removing from impure tungsten carbide particles, the trace metals which react with molten alkali metal pyrosulfates, which comprises contacting the impure tungstencar'b'idewith a molten alkali metal pyrosulfate, thereb-y extracting thetrace metals 'in'tothe molten salt and thereafter separating the purified tungsten c'arbide from the fusion mass.
2. The process of claim 1 wherein the is potassium pyrosulfate.
3. The process of claim 1 where the reaction product is extracted with water.
4. The process of claim 2 where the reaction'product is extracted with water.
5. The process of claim 4 where water-extracted 'tung' pyrosulfate salt sten carbide is treated first with a base, then with an acid, and thereupon washed with water.
6. The process of claim 1 wherein the impure tungsten carbide is a tungsten carbide resulting from the reduction of tungsten oxide ore with carbon.
7. A process as in claim 6 wherein the pyrosulfate salt is potassium pyrosulfate.
8. The process as in claim 7 wherein the fusion mass is extracted with water and the separated tungsten carbide is treated first with a base, second with an acid, and third with water.
9. The process as in claim 8 wherein the base is ammonium hydroxide and the acidis hydrochloric acid.
No references cited.
Claims (1)
1. A PROCESS FOR REMOVING FROM IMPURE TUNGSTEN CARBIDE PARTICLES, THE TRACE METALS WHICH REACT WITH MOLTEN ALKALI METAL PYROSULFATES, WHICH COMPRISES CONTACTING THE IMPURE TUNGSTEN CARBIDE WITH A MOLTEN ALKLI METAL PYROSULFATE, THEREBY EXTRACTING THE TRACE METALS INTO THE MOLTEN SALT AND THEREAFTER SEPARATING THE PURIFIED TUNGSTEN CARBIDE FROM THE FUSION MASS.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US642667A US2913315A (en) | 1957-02-27 | 1957-02-27 | Tungsten carbide purification |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US642667A US2913315A (en) | 1957-02-27 | 1957-02-27 | Tungsten carbide purification |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2913315A true US2913315A (en) | 1959-11-17 |
Family
ID=24577526
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US642667A Expired - Lifetime US2913315A (en) | 1957-02-27 | 1957-02-27 | Tungsten carbide purification |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2913315A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4216009A (en) * | 1977-07-27 | 1980-08-05 | Sumitomo Electric Industries, Ltd. | Method of making alloy and carbide powders of molybdenum and tungsten |
-
1957
- 1957-02-27 US US642667A patent/US2913315A/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| None * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4216009A (en) * | 1977-07-27 | 1980-08-05 | Sumitomo Electric Industries, Ltd. | Method of making alloy and carbide powders of molybdenum and tungsten |
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