GB2291052A - Production of rutile titanium dioxide - Google Patents
Production of rutile titanium dioxide Download PDFInfo
- Publication number
- GB2291052A GB2291052A GB9512960A GB9512960A GB2291052A GB 2291052 A GB2291052 A GB 2291052A GB 9512960 A GB9512960 A GB 9512960A GB 9512960 A GB9512960 A GB 9512960A GB 2291052 A GB2291052 A GB 2291052A
- Authority
- GB
- United Kingdom
- Prior art keywords
- nuclei
- process according
- rutile
- per cent
- titanium dioxide
- 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.)
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 155
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 238000000034 method Methods 0.000 claims abstract description 43
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 36
- HDUMBHAAKGUHAR-UHFFFAOYSA-J titanium(4+);disulfate Chemical compound [Ti+4].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O HDUMBHAAKGUHAR-UHFFFAOYSA-J 0.000 claims abstract description 33
- 239000013078 crystal Substances 0.000 claims abstract description 25
- 239000000203 mixture Substances 0.000 claims abstract description 19
- 239000000725 suspension Substances 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
- 239000000243 solution Substances 0.000 claims description 36
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- 238000001354 calcination Methods 0.000 claims description 11
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 7
- 239000007864 aqueous solution Substances 0.000 claims description 7
- 235000011149 sulphuric acid Nutrition 0.000 claims description 7
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 claims description 7
- 239000001117 sulphuric acid Substances 0.000 claims description 6
- 239000010936 titanium Substances 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 5
- 230000007062 hydrolysis Effects 0.000 claims description 5
- 238000006460 hydrolysis reaction Methods 0.000 claims description 5
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 239000001164 aluminium sulphate Substances 0.000 claims description 3
- 235000011128 aluminium sulphate Nutrition 0.000 claims description 3
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 claims description 3
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 claims description 3
- BUACSMWVFUNQET-UHFFFAOYSA-H dialuminum;trisulfate;hydrate Chemical compound O.[Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O BUACSMWVFUNQET-UHFFFAOYSA-H 0.000 claims description 3
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 3
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 claims description 3
- 229910052939 potassium sulfate Inorganic materials 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 150000001399 aluminium compounds Chemical class 0.000 claims description 2
- 150000003868 ammonium compounds Chemical class 0.000 claims description 2
- 239000001120 potassium sulphate Substances 0.000 claims description 2
- 235000011151 potassium sulphates Nutrition 0.000 claims description 2
- 230000001376 precipitating effect Effects 0.000 claims description 2
- 150000001339 alkali metal compounds Chemical class 0.000 claims 1
- 150000001875 compounds Chemical class 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 239000003973 paint Substances 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000000049 pigment Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 4
- 238000007792 addition Methods 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000005569 Iron sulphate Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000001132 aluminium potassium sulphate Substances 0.000 description 1
- 235000011126 aluminium potassium sulphate Nutrition 0.000 description 1
- 229940077746 antacid containing aluminium compound Drugs 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 description 1
- 239000006012 monoammonium phosphate Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- 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
- C01G23/0534—Producing by wet processes, e.g. hydrolysing titanium salts by hydrolysing sulfate-containing salts in the presence of seeds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
-
- 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
-
- 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
- C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Nanotechnology (AREA)
- Organic Chemistry (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Materials Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Composite Materials (AREA)
- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
A process for the formation of rutile titanium dioxide from a titanium sulphate solution comprises heating the titanium sulphate in the presence of a suspension of nuclei comprising a mixture of rutile-promoting nuclei and non-rutilising nuclei in which mixture the proportion of rutile-promoting nuclei is not greater than 25% by weight. The hydrous titanium dioxide formed is calcined to form rutile having a higher average crystal size than would be expected if the titanium sulphate had been hydrolysed in the presence of the same quantity of rutile-promoting nuclei. Rutile with a large average crystal size is useful in specialist pigmentary applications such as infra-red reflecting paints.
Description
This invention relates to a process for the production of rutile titanium dioxide and in particular to a process which controls the crystal size of rutile titanium dioxide prepared from titanium sulphate solutions.
In the preparation of titanium dioxide by the so-called "sulphate" process an aqueous solution of a titanium sulphate is hydrolysed to precipitate hydrous titanium dioxide generally in the presence of nuclei. Usually, after drying, this titanium dioxide is obtained in the anatase crystal form unless specific steps are taken to assist conversion to the rutile form. If the hydrous titanium dioxide is precipitated in the presence of rutile-promoting nuclei then the rutile crystal form is produced relatively easily during the calcination step which is conventionally used in the preparation of titanium dioxide pigments.
Alternatively, rutile-promoting "seeds" can be added to the precipitated titanium dioxide before calcination or the conversion to rutile can be achieved by prolonged heating and/or relatively high calcination temperatures.
It is an object of the present invention to provide a process for preparing rutile titanium dioxide in which the conversion of anatase to rutile is controlled so as to produce rutile titanium dioxide having useful properties.
According to the invention, a process for the production of rutile titanium dioxide comprises forming an aqueous solution of titanium sulphate, heating said solution in the presence of a suspension of nuclei, thereby precipitating hydrous titanium dioxide and calcining the hydrous titanium dioxide formed wherein the suspension of nuclei comprises a mixture of rutilepromoting nuclei and non-rutilising nuclei and said mixture contains not more than 25 per cent by weight rutile-promoting nuclei with respect to total weight of nuclei.
It has been found, surprisingly, that the use of a mixture of nuclei according to the invention leads to the formation of rutile titanium dioxide having a larger crystal size than would be expected from a conventional process using similar conditions but in which all the nuclei used are rutilepromoting.
Furthermore, the process can be employed to produce rutile titanium dioxide having a mean crystal size larger than that normally produced as a conventional pigment. Rutile titanium dioxide having a large crystal size is useful, for example, as a pigment for reflecting infra-red light.
The process uses a mixture of two forms of nuclei which have been termed "non-rutilising" and "rutile-promoting". The two forms of nuclei can be distinguished by the crystal form of the titanium dioxide produced by utilising the nuclei in a hydrolysis of titanium sulphate. In a suitable test, titanium sulphate solution is hydrolysed in the presence of2 per cent nuclei by weight with respect to potential TiO2 in the titanium sulphate solution. After filtration, the precipitated titanium dioxide is dried and calcined at 950"C for 2V2 hours and the crystal form is determined by X-ray diffraction. Rutile promoting nuclei produce titanium dioxide which is principally in the rutile crystal form whereas the titanium dioxide produced by the use of non-rutilising nuclei is principally in the anatase crystal form.
Generally, rutile-promoting nuclei either comprise rutile at ordinary room temperatures or are converted to rutile when heated at a temperature of 600"C or less, although this test is not necessarily conclusive. Usually, in nonrutilising nuclei the rutile crystal form is undetectable by X-ray diffraction on a powder prepared by drying a sample of the nuclei.
A typical process for preparing rutile-promoting nuclei comprises rapidly adding an aqueous solution of titanium tetrachloride containing the equivalent of about 200 grams per litre TiO2 to a solution of sodium hydroxide.
Nuclei prepared in this way typically contain 10-20 per cent of the titanium dioxide in the rutile form when freshly prepared.
The non-rutilising nuclei can also be prepared by the hydrolysis of an aqueous titanium tetrachloride solution (typically containing the equivalent of 200 grams per litre TiO2). However, for non-rutilising nuclei, sulphuric acid (usually at a TiO2 :H2SO4 ratio of about 1.5:1) is added to the titanium tetrachloride solution and the sodium hydroxide solution is added rapidly.
A number of other methods for the production of rutile-promoting nuclei and non-rutilising nuclei are known in the art of preparation of titanium dioxide pigments and, generally, nuclei made by any suitable method can be employed in the process of this invention.
The size of nuclei of use in the precipitation of titanium dioxide can be extremely difficult to measure. However, it is believed that one particular form of rutile-promoting nuclei is acicular with an average length in the range 10 nm to 20 nm and an average width in the range 5 nm to 10 nm. One form of nonrutilising nuclei is believed to be approximately spherical with an average particle diameter in the range 2 nm to 8 nm.
The titanium sulphate solution used in the process of the invention can be any titanium sulphate suitable for use in the well-known "sulphate" process for the preparation of titanium dioxide pigments. The solution is usually prepared by digesting a titaniferous ore with concentrated sulphuric acid to produce a digestion cake which is then dissolved in water or dilute acid to form the titanium sulphate solution. A number of titaniferous ores can be used, typical ores being ilmenite and slag.
The titanium sulphate solution usually contains iron sulphate and other impurities in addition to the titanium sulphate and is usually treated with a reducing agent and filtered before it is converted into hydrous titanium dioxide in accordance with the method of this invention. The solution is often referred to as titanyl sulphate solution although this does not imply any specific chemical composition. Solutions having a range of titanium to sulphate ratios can be employed. Usually the Ti:SO4 molar ratio is in the range 1.4:1 to 1.8:1 and preferably the ratio is in the range 1.5:1 to 1.7:1.
The concentration of the titanium sulphate solution is normally expressed in terms of the potentially available titanium dioxide and is usually in the range 100 to 300 grams per litre TiO2. Preferably, the concentration is from 150 to 250 grams per litre TiO2 and a particularly convenient range is 180 to 200 grams per litre Till.
The total quantity of nuclei used in the process of the invention to precipitate hydrous titanium dioxide from the titanium sulphate solution depends upon a number of factors including the desired crystal size of the titanium dioxide finally produced. Amounts within the range 0.2 to 10 per cent by weight of TiO2 in the nuclei with respect to titanium content of the titanium sulphate solution (expressed as TiO2) are usually employed. Preferably, the amount is up to 6 per cent by weight and more preferably from 0.25 to 2.0 per cent by weight. A typical process according to the invention for producing rutile titanium dioxide with an average crystal size about 0.4 micrometres uses from 1.6 to 2.0 per cent nuclei by weight (as TiO2 with respect to potential
TiO2 in the titanium sulphate solution).
The crystal size of the product rutile titanium dioxide is also influenced by the ratio of the amount of rutile-promoting nuclei to the amount of nonrutilising nuclei present in the suspension of nuclei. According to the process ofthe invention the proportion of rutile-promoting nuclei in the suspension is less than 25 per cent by weight. Preferably, the proportion is less than 15 per cent and most preferably it is from 1 to 10 per cent by weight.
A mixture of the two forms of nuclei can be prepared before this mixture is added to the titanium sulphate solution but the two forms can be added separately to the solution. Alternatively, the non-rutilising nuclei can be generated by a partial hydrolysis of the titanium sulphate solution and the rutile-promoting nuclei are subsequently added to this prepared mixture.
Typically, hydrolysis of the titanium sulphate is effected in the presence of the nuclei by raising the titanium sulphate solution to its boiling point and continuing heating to precipitate substantially all the available titanium dioxide.
The precipitated hydrous titanium dioxide is recovered by filtration, decantation or other conventional methods and, after separation, is usually washed with water and, if necessary, leached with small concentrations of sulphuric acid or other suitable reagents. The washed precipitate is then usually treated with one or more small additions of alkali metal or ammonium compounds such as potassium sulphate or ammonium dihydrogen phosphate and with aluminium compounds such as aluminium sulphate each of which is present in an amount of from 0.2% to 0.9% by weight as oxide on TiO content of the precipitated hydrous titanium dioxide.
Usually, the additioned precipitate is then dewatered and calcined to convert it to rutile titanium dioxide having the chosen crystal size. The length of time for which the titanium dioxide is heated is usually controlled by determining the degree of conversion to rutile. Normally, the titanium dioxide is calcined until at least 96 per cent by weight is present in the rutile crystal form. Preferably, at least 98 per cent rutile is present after calcination.
Calcination is usually carried out at a temperature in the range 800"C to 1200"C and preferably in the range 900"C to 1050"C. The choice oftime and temperature for calcination depends upon a number of factors. It is more economical to employ a temperature at the lower end of the above range but the conversion to rutile is then slower than at higher temperatures.
By comparison to conventional methods utilising only rutile-promoting nuclei it will generally be necessary to operate at a slightly increased calcination temperature in order to achieve a specified degree of conversion to rutile.
The method of the invention provides a means of preparing rutile titanium dioxide having a controlled crystal size. It is particularly useful for preparing rutile with a crystal size larger than is conventionally produced for titanium dioxide pigments. Rutile with this large crystal size is useful in specialist pigmentary applications such as for infra-red reflecting paints.
The invention is illustrated by the following examples.
EXAMPLE 1
To 3 litres of a titanium sulphate liquor containing the equivalent of 185 grams TiO2 per litre, 110 grams per litre Fe and 350 grams per litre free sulphuric acid was added nuclei in an amount equivalent to 1.8 weight per cent (calculated as TiO2) with respect to potential TiO2 in the titanium sulphate liquor. The nuclei consisted of a mixture of 9 parts by weight non-rutilising nuclei and 1 part by weight rutile-promoting nuclei. The rutile-promoting nuclei were prepared by rapid addition of an aqueous solution of titanium tetrachloride to a solution of sodium hydroxide followed by ageing by heating, quenching by cooling and neutralisation. The non-rutilising nuclei were prepared by forming a mixture of sulphuric acid and aqueous titanium tetrachloride and rapidly adding sodium hydroxide solution. The mixture was aged by heating, quenched by cooling and neutralised.
The titanium sulphate liquor containing the nuclei was heated to boiling and maintained at boiling for 3 hours to precipitate hydrous titanium dioxide which was separated by filtration, washed, leached, re-filtered and washed.
Standard calcination additions of aluminium sulphate, potassium sulphate and monoammonium phosphate solutions were made and the powder was heated at 970"C in a muffle fumace to achieve 97% conversion to rutile in 21/2 hours.
The calcined product had a crystal size of 0.4 micrometres.
EXAMPLE A (Comparative)
Example 1 was repeated except that the nuclei added (1.8 per cent by weight of TiO2 with respect to potential TiO2) were all rutilising nuclei.
The product had a crystal size of0.21 micrometres.
Claims (25)
1. A process for the production of rutile titanium dioxide comprising forming an aqueous solution oftitanium sulphate, heating said solution in the presence of a suspension of nuclei, thereby precipitating hydrous titanium dioxide, and calcining the hydrous titanium dioxide formed wherein the suspension of nuclei comprises a mixture of rutile-promoting nuclei and nonrutilising nuclei and said mixture contains not more than 25 per cent by weight rutile-promoting nuclei with respect to total weight of nuclei.
2. A process according to claim 1 in which the rutile-promoting nuclei are prepared by adding an aqueous solution of titanium tetrachloride to a solution of sodium hydroxide.
3. A process according to claim 2 in which the rutile-promoting nuclei contain from 10 per cent to 20 per cent by weight rutile titanium dioxide.
4. A process according to any one of the preceding claims in which the non-rutilising nuclei are prepared by adding a solution of sodium hydroxide to an aqueous solution of titanium tetrachloride containing sulphuric acid.
5. A process according to any one of the preceding claims in which the rutile-promoting nuclei and the non-rutilising nuclei are separately added to the titanium sulphate solution.
6. A process according to any one of claims 1 to 3 in which the nonrutilising nuclei are generated by a partial hydrolysis of the titanium sulphate solution and the rutile-promoting nuclei are subsequently added to this mixture of non-rutilising nuclei and titanium sulphate.
7. A process according to any one of the preceding claims in which the rutile-promoting nuclei are acicular with an average length in the range 10 nm to 20 nm and an average width in the range 5 nm to 10 nm.
8. A process according to any one of claims 1 to 6 in which the nonrutilising nuclei are approximately spherical with an average diameter in the range 2 nm to 8 nm.
9. A process according to any one of the preceding claims in which the mixture of nuclei contains less than 15 per cent by weight rutile-promoting nuclei with respect to total weight of nuclei.
10. A process according to claim 9 in which the mixture of nuclei contains from 1 per cent to 10 per cent by weight rutile-promoting nuclei with respect to total weight of nuclei.
11. A process according to any one of the preceding claims in which the suspension of nuclei is present in an amount within the range 0.2 per cent to 10 per cent by weight calculated as weight of TiO2 in the nuclei with respect to titanium content of the titanium sulphate solution expressed as TiO2.
12. A process according to claim 11 in which the amount of nuclei present is from 0.2 per cent to 6 per cent by weight.
13. A process according to claim 12 in which the amount of nuclei present is from 0.25 per cent to 2.0 per cent by weight.
14. A process according to claim 13 in which the amount of nuclei present is from 1.6 per cent to 2.0 per cent by weight.
15. A process according to any one ofthe preceding claims in which the solution of titanium sulphate has a composition such that the Ti:SO4 molar ratio is in the range 1.4:1 to 1.8:1.
16. A process according to claim 15 in which the Ti:SO4 molar ratio is in the range 1.5:1 to 1.7:1.
17. A process according to any one of the preceding claims in which the titanium sulphate solution has a concentration equivalent to from 100 to 300 grams of TiO2 per litre.
18. A process according to claim 17 in which the concentration of titanium sulphate solution is equivalent to from 150 to 250 grams of TiO2 per litre.
19. A process according to claim 17 or 18 in which the concentration of the titanium sulphate solution is equivalent to from 180 to 200 grams of TiO2 per litre.
20. A process according to any one of the preceding claims in which the precipitated hydrous titanium dioxide is separated, washed and calcined in the presence of one or more alkali metal compound, ammonium compound or aluminium compound each compound being present in an amount of from 0.2 to 0.9 per cent by weight calculated as oxide on TiO2 content of the precipitated hydrous titanium dioxide.
21. A process according to claim 20 in which one or more of potassium sulphate, ammonium dihydrogen phosphate and aluminium sulphate is present during calcination.
22. A process according to any one of the preceding claims in which the precipitated hydrous titanium dioxide is calcined until at least 96 per cent by weight is present in the rutile crystal form.
23. A process according to claim 22 in which the precipitated hydrous titanium dioxide is calcined until at least 98 per cent by weight is present in the rutile crystal form.
24. A process according to any one of the preceding claims in which the precipitated hydrous titanium dioxide is calcined at a temperature in the range 800"C to 1200"C.
25. A process according to claim 24 in which the precipitated hydrous titanium dioxide is calcined at a temperature in the range 900"C to 1050"C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9512960A GB2291052B (en) | 1994-07-13 | 1995-06-26 | Production of rutile titanium dioxide |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9414141A GB9414141D0 (en) | 1994-07-13 | 1994-07-13 | Production of rutile titanium dioxide |
| GB9512960A GB2291052B (en) | 1994-07-13 | 1995-06-26 | Production of rutile titanium dioxide |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9512960D0 GB9512960D0 (en) | 1995-08-30 |
| GB2291052A true GB2291052A (en) | 1996-01-17 |
| GB2291052B GB2291052B (en) | 1998-01-07 |
Family
ID=26305259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9512960A Expired - Fee Related GB2291052B (en) | 1994-07-13 | 1995-06-26 | Production of rutile titanium dioxide |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2291052B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2308118A (en) * | 1995-12-15 | 1997-06-18 | Tioxide Group Services Ltd | Rutile titanium dioxide |
| WO2009136141A1 (en) * | 2008-05-07 | 2009-11-12 | Tioxide Europe Limited | Titanium dioxide |
| CN101698505B (en) * | 2009-11-06 | 2012-09-05 | 攀钢集团研究院有限公司 | Method for preparing additional hydrolyzing seed crystal |
| US9221995B2 (en) | 2008-05-07 | 2015-12-29 | Tioxide Europe Limited | Titanium dioxide |
| CN106430302A (en) * | 2016-09-05 | 2017-02-22 | 衡阳师范学院 | Preparation method of anatase titanium dioxide additional hydrolysis crystal seeds |
| WO2020122740A1 (en) * | 2018-12-14 | 2020-06-18 | Avertana Limited | Methods of extraction of products from titanium-bearing materials |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112939071A (en) * | 2021-02-22 | 2021-06-11 | 安徽英特力工业工程技术有限公司 | Preparation and storage method of titanium tetrachloride crystal seed |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1254208A (en) * | 1968-03-05 | 1971-11-17 | Thann Fab Prod Chem | Process for the manufacture of pigments of titanium dioxide in the rutile form, and pigments produced thereby |
-
1995
- 1995-06-26 GB GB9512960A patent/GB2291052B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1254208A (en) * | 1968-03-05 | 1971-11-17 | Thann Fab Prod Chem | Process for the manufacture of pigments of titanium dioxide in the rutile form, and pigments produced thereby |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2308118A (en) * | 1995-12-15 | 1997-06-18 | Tioxide Group Services Ltd | Rutile titanium dioxide |
| WO2009136141A1 (en) * | 2008-05-07 | 2009-11-12 | Tioxide Europe Limited | Titanium dioxide |
| RU2502761C2 (en) * | 2008-05-07 | 2013-12-27 | Тиоксид Юроп Лимитед | Titanium dioxide |
| US9127172B2 (en) | 2008-05-07 | 2015-09-08 | Tioxide Europe Limited | Titanium dioxide |
| US9221995B2 (en) | 2008-05-07 | 2015-12-29 | Tioxide Europe Limited | Titanium dioxide |
| CN101698505B (en) * | 2009-11-06 | 2012-09-05 | 攀钢集团研究院有限公司 | Method for preparing additional hydrolyzing seed crystal |
| CN106430302A (en) * | 2016-09-05 | 2017-02-22 | 衡阳师范学院 | Preparation method of anatase titanium dioxide additional hydrolysis crystal seeds |
| WO2020122740A1 (en) * | 2018-12-14 | 2020-06-18 | Avertana Limited | Methods of extraction of products from titanium-bearing materials |
| US12172905B2 (en) | 2018-12-14 | 2024-12-24 | Avertana Limited | Methods of extraction of products from titanium-bearing materials |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9512960D0 (en) | 1995-08-30 |
| GB2291052B (en) | 1998-01-07 |
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| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20000626 |