GB2322366A - Anatase titanium dioxide - Google Patents
Anatase titanium dioxide Download PDFInfo
- Publication number
- GB2322366A GB2322366A GB9810209A GB9810209A GB2322366A GB 2322366 A GB2322366 A GB 2322366A GB 9810209 A GB9810209 A GB 9810209A GB 9810209 A GB9810209 A GB 9810209A GB 2322366 A GB2322366 A GB 2322366A
- Authority
- GB
- United Kingdom
- Prior art keywords
- titanium dioxide
- micrometre
- anatase
- anatase titanium
- average
- 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.)
- Granted
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/08—Drying; Calcining ; After treatment of titanium oxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
- C01G23/0532—Producing by wet processes, e.g. hydrolysing titanium salts by hydrolysing sulfate-containing salts
-
- 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
-
- 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
- C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/60—Compounds characterised by their crystallite size
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/51—Particles with a specific particle size distribution
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Anatase titanium dioxide which has been milled to form a product with a high single crystal fraction, has an average crystal size greater than 0.20 micrometres and an average particle size less than 0.28 micrometres.
Description
ANATASE TITANIUM DIOXIDE
This invention relates to anatase titanium dioxide having a large crystal size.
The manufacture of titanium dioxide pigment by the so-called "sulphate process" has become well established producing two types of pigment, anatase titanium dioxide and the more valuable and technically important rutile titanium dioxide.
The pigmentary properties of rutile titanium dioxide make the pigment the preferred one but anatase does possess a higher degree of whiteness and brightness which are important in certain uses.
Consequently it would be advantageous if anatase titanium dioxide could be made with at least some improved pigment properties. In particular anatase titanium dioxide having a larger crystal size than is conventionally available is now recognised as desirable.
In the sulphate process a titaniferous ore is digested with concentrated sulphuric acid and the cake obtained is dissolved in weak acid or water to produce a solution of a titanium sulphate. This titanium sulphate is subsequently hydrolysed to precipitate hydrous titanium oxide either by the deliberate addition of nuclei ('Mecklenburg' process) or by inducing nuclei within the solution by the addition of water ('Blumenfeld') process.
A process for making large crystal anatase using added nuclei has recently been described in GB 2 247 009. The current invention provides anatase of even larger crystal size which is more easily milled than that of
GB 2 247 009.
According to the invention, there is provided anatase titanium dioxide having an average crystal size greater than 0.2 micrometre and an average particle size less than 0.28 micrometre.
Preferably, the average particle size is less than 0.28 micrometre and, more preferably, the average crystal size is in the range 0.25 to 0.27 micrometre and an average particle size in the range 0.27 to 0.29 micrometre.
The geometric weight standard deviation of the crystal size is generally in the range 1.30 to 1.50 and frequently in the range 1.35 to 1.40.
In comparison with the products of GB 2 247 009, it has been found that the products of this invention can be milled relatively easily. It is therefore possible to produce by milling, a product having a high single crystal fraction (i.e. the average particle size is only slightly higher than the average crystal size). In particular, the process of the invention provides a method for producing anatase titanium dioxide having an average crystal size greater than 0.20 micrometre and an average particle size less than 0.29 micrometre and preferably less than 0.28 micrometre. In a preferred product formed by milling the average crystal size is in the range 0.25 to 0.27 micrometre and the average particle size is in the range 0.27 to 0.29 micrometre.
Generally, at least 90% by weight of the product is in the anatase crystal form and preferably at least 95% is in the anatase form,
A process for the preparation of the product of the invention is disclosed and claimed in GB-A-2297082 from which this application has been divided.
Uncoated products of this invention are useful in producing paper, paper coatings and cosmetics and as food additives. The coated products are useful for paints, especially emulsion paints and for inks, radiation-cured coatings, rubber and plastics. Generally the opacity of the products of this invention is improved compared to conventional anatase products that have a smaller average crystal size and the whiteness and brightness of the products is improved over rutile. The products are especially useful when used in conjunction with optical brighteners.
The invention is illustrated by the following example.
EXAMPLE
An aqueous solution of titanium sulphate containing the equivalent of 250 grams TiO2 per litre and an acid to titanium ratio by weight, of 1.82 was hydrolysed by the addition of water in a proportion of 20.5 parts water per 100 parts titanium sulphate by weight. The water was added to the titanium sulphate solution at a temperature of 90"C over a period of 15 minutes. The mixture was maintained at a temperature of90"C for 220
minutes when hydrolysis was complete. The precipitated titanium oxide was separated by filtration using a Moore filter and further dewatered on a pressure filter.
The filter cake was fed to a calciner at a feed rate of 2.9 te filter cake per hour. A concentrated solution of potassium hydroxide and phosphoric acid was added to the calciner feed at a rate sufficient to introduce 0.30% K2O and 0.39% P205 by weight with respect to TiO2. The average gas temperature of the zone into which the filter cake was introduced was 524"C and the titanium oxide was heated in this zone and a second zone to 680"C with an average residence time in the two zones combined of 240 minutes. The titanium oxide was subsequently heated to 750"C over a period of 30 minutes in a third zinc, to 880"C over a period of 60 minutes in a fourth zone, to 925"C over a period of 40 minutes in a fifth zone and was finally discharged from the calciner at a temperature of 985"C after a further 80 minutes residence in a sixth zone.
The final product was found to have an average crystal size of 0.25 micrometre and 99% was in the anatase crystal form.
After coating with alumina and silica using a standard recipe it was used to prepare an emulsion paint which had a higher opacity than a paint made from a conventional anatase pigment with a similar inorganic coating.
Claims (3)
1. Anatase titanium dioxide having an average crystal size greater than 0.20 micrometre and an average particle size less than 0.29 micrometre.
2. Anatase titanium dioxide according to claim 1 having an average particle size less than 0.28 micrometre.
3. Anatase titanium dioxide according to claim 1 having an average crystal size in the range 0.25 to 0.27 micrometre and an average particle size in the range 0.27 to 0.29 micrometre.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9810209A GB2322366B (en) | 1995-01-20 | 1996-01-03 | Anatase titanium dioxide |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9501086.4A GB9501086D0 (en) | 1995-01-20 | 1995-01-20 | Preparation of anatase titanium dioxide |
| GB9810209A GB2322366B (en) | 1995-01-20 | 1996-01-03 | Anatase titanium dioxide |
| GB9600045A GB2297082B (en) | 1995-01-20 | 1996-01-03 | Preparation of anatase titanium dioxide |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9810209D0 GB9810209D0 (en) | 1998-07-08 |
| GB2322366A true GB2322366A (en) | 1998-08-26 |
| GB2322366B GB2322366B (en) | 1999-04-07 |
Family
ID=26306347
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9810209A Expired - Fee Related GB2322366B (en) | 1995-01-20 | 1996-01-03 | Anatase titanium dioxide |
| GBGB9801209.9A Ceased GB9801209D0 (en) | 1995-01-20 | 1998-01-03 | Communications system |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB9801209.9A Ceased GB9801209D0 (en) | 1995-01-20 | 1998-01-03 | Communications system |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB2322366B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017212286A1 (en) * | 2016-06-10 | 2017-12-14 | Huntsman P&A Uk Limited | Titanium dioxide product |
-
1996
- 1996-01-03 GB GB9810209A patent/GB2322366B/en not_active Expired - Fee Related
-
1998
- 1998-01-03 GB GBGB9801209.9A patent/GB9801209D0/en not_active Ceased
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017212286A1 (en) * | 2016-06-10 | 2017-12-14 | Huntsman P&A Uk Limited | Titanium dioxide product |
| US11130866B2 (en) | 2016-06-10 | 2021-09-28 | Venator Materials Uk Limited | Titanium dioxide product |
| TWI743134B (en) * | 2016-06-10 | 2021-10-21 | 英商凡納特材料英國公司 | Titanium dioxide product |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9810209D0 (en) | 1998-07-08 |
| GB9801209D0 (en) | 1998-03-18 |
| GB2322366B (en) | 1999-04-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010103 |