US2756157A - Preparation of monocrystalline rutile - Google Patents
Preparation of monocrystalline rutile Download PDFInfo
- Publication number
- US2756157A US2756157A US373884A US37388453A US2756157A US 2756157 A US2756157 A US 2756157A US 373884 A US373884 A US 373884A US 37388453 A US37388453 A US 37388453A US 2756157 A US2756157 A US 2756157A
- Authority
- US
- United States
- Prior art keywords
- rutile
- boule
- single crystal
- oxygen
- preparation
- 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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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims description 36
- 238000002360 preparation method Methods 0.000 title description 6
- 150000001875 compounds Chemical class 0.000 claims description 7
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 claims description 6
- 229910052733 gallium Inorganic materials 0.000 claims description 6
- 239000013078 crystal Substances 0.000 description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 13
- 239000001301 oxygen Substances 0.000 description 13
- 229910052760 oxygen Inorganic materials 0.000 description 13
- AJNVQOSZGJRYEI-UHFFFAOYSA-N digallium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Ga+3].[Ga+3] AJNVQOSZGJRYEI-UHFFFAOYSA-N 0.000 description 8
- 229910001195 gallium oxide Inorganic materials 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- 150000002259 gallium compounds Chemical class 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000010405 reoxidation reaction Methods 0.000 description 2
- -1 salt ammonium-titanium-sulfate Chemical class 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 239000010902 straw Substances 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 244000144725 Amygdalus communis Species 0.000 description 1
- 235000011437 Amygdalus communis Nutrition 0.000 description 1
- 244000000626 Daucus carota Species 0.000 description 1
- 235000002767 Daucus carota Nutrition 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- VULAXXNFNMUCIP-UHFFFAOYSA-M [NH4+].[O-]S(=O)(=O)O[Ti] Chemical compound [NH4+].[O-]S(=O)(=O)O[Ti] VULAXXNFNMUCIP-UHFFFAOYSA-M 0.000 description 1
- 235000020224 almond Nutrition 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 238000007580 dry-mixing Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 239000010437 gem Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/16—Oxides
- C30B29/22—Complex oxides
- C30B29/26—Complex oxides with formula BMe2O4, wherein B is Mg, Ni, Co, Al, Zn, or Cd and Me is Fe, Ga, Sc, Cr, Co, or Al
Definitions
- the present invention relates to rutile single crystal boules modified with respect to color and certain other physical properties, and to methods for the production of such boules.
- Rutile is one of the three known crystal modifications of titanium dioxide. When substantially pure, a massive single crystal of rutile has gem-like properties with a very light straw color and reflectance, refraction and brilliance greater than that of a diamond. By means of the present invention rutile single crystals may be produced which have a nearly water-white color. In addition, the present invention permits finishing the boule by reoxidation in considerably less time than is required for a pure rutile single crystal boule.
- the principal object of the present invention is the preparation of rutile single crystal boules having nearly water-white color.
- Another object of the invention is a method for producing a finished, oxidized rutile single crystal boule in considerably less time than is required for the preparation of a finished oxidized pure rutile single crystal boule.
- the present invention contemplates a rutile single crystal boule containing a small amount of an oxidic compound of gallium in solid solution and charabterized by having a nearly water-white color.
- This water-white single crystal may be prepared according to the method of the present invention byprogressively fusing a mixture of finely divided TiOz containing a small amount of an oxidic compound of gallium in a flame carrying an excess of an oxidizing gas and thereafter oxidizing boule so formed.
- boule is used in its currently accepted meaning to denote a characteristic shape or form of an artificially prepared massive single crystal having a rounded end, or meniscus, a more or less rod-like body portion and a tapering end, giving an overall appearance in profile of an almond, or carrot.
- a substantially pure TiOz which is very fine, fairly uniform and possesses an open structure with units capable of being rapidly melted.
- a TiOz having an ultimate unit particle size of approximately 0.1 micron has proved especially satisfactory.
- material having an average particle size above about 5 microns should be avoided because such particles do not satisfactoriiy fuse under the conditions of the invention.
- a preferred method for preparing a T iOz starting material especially adapted for the production of rutile single crystal boules is described in U. 8. Patent No. 2,521,392, issued September 5, 1950,
- the small amount of gallium compound maybe mixed with the TiOz starting material in any convenient manner, for instance, by dry mixing.
- a more uniform mixture and, therefore, a preferred mixture may be prepared by adding gallium oxide as a powder, slurry, or solution to the double salt, ammonium-titanium-sulfate prior to calcination.
- the amount of gallium compound to be added to the TiOz starting material should not exceed about 1.0%, calculated as gallium oxide based on the weight of the TiOz.
- the lower limit which is effective is about 0.05%.
- amounts of gallium oxide of about 1.0% and below a complete solid solution of the gallium oxide in the TiOz is formed from which a high quality unfractured boule is produced.
- a flame which carries an excess of an oxidizing gas, preferably oxygen.
- an oxidizing gas preferably oxygen.
- the fusion is carried out according to the method described in application Serial No. 286,853 supra, in which the particles of the starting mixture are entrained in a stream of oxygen in a tube constituting the center of a burner consisting of three concentric tubes.
- hydrogen is introduced to the flame through the intermediate tube and additional oxygen in excess over the amount required to combine with the hydrogen is introduced through the outer tube.
- the ratio of oxygen to hydrogen by volume should be about 1:1 and should not be less than about 8.5 parts of oxygen to 9.5 parts hydrogen by volume.
- the boule as produced has a generally deep blue-black color indica- I tive of some deficiency in oxygen. Therefore, in order to produce the nearly water-white boule of the present invention, the blue-black boule has to be re-oxidized.
- the reoxidation of the boule is preferably carried out by heating the blue-black boule in an oxidizing atmos phere, for instance, air or oxygen.
- the temperature of the treatment should be within the range from about 650 C. to about 1500 C. It has been found that temperatures to any extent below 650 C. oxygen will not be appreciably incorporated into the rutile single crystal while temperatures above 1500 C. are expensive and difficult to maintain.
- the heating should be continued until the boule obtains the maximum degree of lightness of color, this time will usually be about one-quarter of that required to fully oxidize a pure rutile boule.
- the gallium oxide containing rutile boule has a more or less frosted outer surface.
- the interior surfaces of the pieces are vitreous and shiny and nearly water-white. They may be cut and polished to form beautiful gems, more brilliant than diamonds and having a white color compared to the characteristic straw or light yellow color of pure rutile.
- a single crystal of synthetic rutile consisting essentially of titania and from about 0.05% to about 1.0% of an oxidic compound of gallium.
- a single crystal of synthetic rutile consisting essentially of titania and from about 0.05% to about 1.0% gallium oxide.
- a method for synthesizing a substantially waterwhite single crystal of rutile consisting of fusing a powder containing titania and from about 0.05% to about 1.0% of an oxidic compound of gallium, crystallizing the fused material and heating the crystallized material in an oxidiz ing atmosphere of oxidizing gas until the water-white color is obtained.
Description
PREPARATION OF MON OCRYSTALLINE RUTILE Malcolm D. Beals, Fanwood, N. J., and James Fill filler, Lancaster, Ohio, assignorsto National Lead Company, New York, N. Y., a corporation of New Jersey No Drawing. Application August 12, 1953, Serial No. 373,884
4 Claims. (Cl. 106-42) The present invention relates to rutile single crystal boules modified with respect to color and certain other physical properties, and to methods for the production of such boules.
Rutile is one of the three known crystal modifications of titanium dioxide. When substantially pure, a massive single crystal of rutile has gem-like properties with a very light straw color and reflectance, refraction and brilliance greater than that of a diamond. By means of the present invention rutile single crystals may be produced which have a nearly water-white color. In addition, the present invention permits finishing the boule by reoxidation in considerably less time than is required for a pure rutile single crystal boule.
The principal object of the present invention is the preparation of rutile single crystal boules having nearly water-white color. Another object of the invention is a method for producing a finished, oxidized rutile single crystal boule in considerably less time than is required for the preparation of a finished oxidized pure rutile single crystal boule. These and other objects of the present invention will become apparent from the following descriptron.
In its broadest aspect the present invention contemplates a rutile single crystal boule containing a small amount of an oxidic compound of gallium in solid solution and charabterized by having a nearly water-white color. This water-white single crystal may be prepared according to the method of the present invention byprogressively fusing a mixture of finely divided TiOz containing a small amount of an oxidic compound of gallium in a flame carrying an excess of an oxidizing gas and thereafter oxidizing boule so formed.
In this description of the present invention the word boule is used in its currently accepted meaning to denote a characteristic shape or form of an artificially prepared massive single crystal having a rounded end, or meniscus, a more or less rod-like body portion and a tapering end, giving an overall appearance in profile of an almond, or carrot.
The general method to which the presentinvention relates is that described in another of assignees applications, that is in co-aending application Serial No. 286,853, filed May 9, 1952, and now abandoned, for the preparation of pure rutile single crystal boules.
According to the preferred method of the present invention, there is employed as starting material a substantially pure TiOz which is very fine, fairly uniform and possesses an open structure with units capable of being rapidly melted. A TiOz having an ultimate unit particle size of approximately 0.1 micron has proved especially satisfactory. In general, material having an average particle size above about 5 microns should be avoided because such particles do not satisfactoriiy fuse under the conditions of the invention. A preferred method for preparing a T iOz starting material especially adapted for the production of rutile single crystal boules is described in U. 8. Patent No. 2,521,392, issued September 5, 1950,
wherein the double salt ammonium-titanium-sulfate is calcined until all of the ammonia and sulfate has been removed by volatilization.
Substantially any oxidic compound of gallium'can be added to the feed material, for example, the sesqui-oxide or any oxidic compounds which form the oxide at the temperatures employed in the preparation of the rutile boules.
According to the present invention the small amount of gallium compound maybe mixed with the TiOz starting material in any convenient manner, for instance, by dry mixing. A more uniform mixture and, therefore, a preferred mixture may be prepared by adding gallium oxide as a powder, slurry, or solution to the double salt, ammonium-titanium-sulfate prior to calcination.
The amount of gallium compound to be added to the TiOz starting material should not exceed about 1.0%, calculated as gallium oxide based on the weight of the TiOz. The lower limit which is effective is about 0.05%. When the amount of gallium oxide is increased substantially above about 1.0% resulting boules tend to fracture and this is to be avoided. With amounts of gallium oxide of about 1.0% and below a complete solid solution of the gallium oxide in the TiOz is formed from which a high quality unfractured boule is produced.
In progressively fusing the starting mixture of "H02 and gallium oxide there should be employed a flame which carries an excess of an oxidizing gas, preferably oxygen. Preferably the fusion is carried out according to the method described in application Serial No. 286,853 supra, in which the particles of the starting mixture are entrained in a stream of oxygen in a tube constituting the center of a burner consisting of three concentric tubes. In this burner hydrogen is introduced to the flame through the intermediate tube and additional oxygen in excess over the amount required to combine with the hydrogen is introduced through the outer tube. Preferably, the ratio of oxygen to hydrogen by volume should be about 1:1 and should not be less than about 8.5 parts of oxygen to 9.5 parts hydrogen by volume.
The excess of oxygen in the flame is necessary because at elevated temperatures, titanium dioxide gives up oxygen and is converted to lower, or sub-oxides of titanium, e. g. TiaOs. This loss of oxygen proceeds with considerable rapidity under conditions produced by an oxy-hydrogen flame wherein the TiO2 is fused and the loss is accelerated when the flame is neutral or reducing. Under such conditions the formation of lower, or sub-oxides of titanium, is so great that mixtures of small crystals of various oxides of titanium are produced rather than a single crystal boule.
Even when operating with an excess of oxygen the boule as produced has a generally deep blue-black color indica- I tive of some deficiency in oxygen. Therefore, in order to produce the nearly water-white boule of the present invention, the blue-black boule has to be re-oxidized.
The reoxidation of the boule is preferably carried out by heating the blue-black boule in an oxidizing atmos phere, for instance, air or oxygen. The temperature of the treatment should be within the range from about 650 C. to about 1500 C. It has been found that temperatures to any extent below 650 C. oxygen will not be appreciably incorporated into the rutile single crystal while temperatures above 1500 C. are expensive and difficult to maintain. The heating should be continued until the boule obtains the maximum degree of lightness of color, this time will usually be about one-quarter of that required to fully oxidize a pure rutile boule.
As produced, the gallium oxide containing rutile boule has a more or less frosted outer surface. When split, the interior surfaces of the pieces are vitreous and shiny and nearly water-white. They may be cut and polished to form beautiful gems, more brilliant than diamonds and having a white color compared to the characteristic straw or light yellow color of pure rutile.
The foregoing description has been given for purposes of illustration, but the invention is not to be limited thereto and various modifications and variations Within the scope of the appended claims maybe employed.
We claim:
1. A single crystal of synthetic rutile consisting essentially of titania and from about 0.05% to about 1.0% of an oxidic compound of gallium.
2. A single crystal of synthetic rutile consisting essentially of titania and from about 0.05% to about 1.0% gallium oxide.
3. A method for synthesizing a substantially waterwhite single crystal of rutile consisting of fusing a powder containing titania and from about 0.05% to about 1.0% of an oxidic compound of gallium, crystallizing the fused material and heating the crystallized material in an oxidiz ing atmosphere of oxidizing gas until the water-white color is obtained.
4. The method according to claim 3 in which the crystallized material is heated in an atmosphere of oxygen at a 10 temperature between about 650 C. and 1500 C.
No references cited.
Claims (1)
1. A SINGLE CRYSTAL FO SYNTHETIC RUTILE CONSISTING ESSENTIALLY OF TITANIA AND FROM ABOUT 0.05% TO ABOUT 1.0% OF AN OXIDIC COMPOUND OF GALLIUM.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US373884A US2756157A (en) | 1953-08-12 | 1953-08-12 | Preparation of monocrystalline rutile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US373884A US2756157A (en) | 1953-08-12 | 1953-08-12 | Preparation of monocrystalline rutile |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2756157A true US2756157A (en) | 1956-07-24 |
Family
ID=23474282
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US373884A Expired - Lifetime US2756157A (en) | 1953-08-12 | 1953-08-12 | Preparation of monocrystalline rutile |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2756157A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3022186A (en) * | 1958-01-11 | 1962-02-20 | Bayer Ag | Mixed phases with a rutile or polyrutile structure |
| US4624776A (en) * | 1984-03-09 | 1986-11-25 | Exxon Research And Engineering Company | Selective removal of coke precursors from hydrocarbon feedstock |
-
1953
- 1953-08-12 US US373884A patent/US2756157A/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| None * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3022186A (en) * | 1958-01-11 | 1962-02-20 | Bayer Ag | Mixed phases with a rutile or polyrutile structure |
| US4624776A (en) * | 1984-03-09 | 1986-11-25 | Exxon Research And Engineering Company | Selective removal of coke precursors from hydrocarbon feedstock |
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