US4052224A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of pigment
Assignee: Tioxide Group Ltd
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Filing: 1976-06-04
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Granted: 1977-10-04
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Expires: 1996-06-04
Abstract
Abstract A process for the treatment of titanium dioxide pigment which involves adding to a pigment slurry a compound of phosphorus, of aluminium, of zirconium, of titanium and of silicon, adjusting the pH of the slurry to a value of from 3.5 to 4.5, followed by adding to the slurry a compound of phosphorus of an alkaline reacting compound of aluminium prior to the addition of mineral acid to adjust the pH of the slurry to a value of 6.5 to 8.
Inventors
- 👤 Peter Barry Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:05
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/36; C09C1/3607; C09C1/3653; C09C1/3661; C01; C01P; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
240 words
A process for the treatment of titanium dioxide pigment which comprises forming an aqueous dispersion of pigmentary titanium dioxide containing a water-soluble compound of phosphorus in an amount of from 0.2 to 1.0% by weight expressed as P 2 O 5 , adding to the dispersion so formed an acidic water-soluble compound of aluminium in an amount of from 2.5 to 3.5% by weight expressed as Al 2 O 3 , a water-soluble acidic compound of zirconium in an amount of from 0.5 to 1.5% by weight expressed as ZrO 2 , an acidic water-soluble compound of titanium in an amount of from 1.5 to 3% by weight expressed as TiO 2 and a water-soluble compound of silicon in an amount of from 0.2 to 2.0% by weight expressed as SiO 2 , adjusting the pH of the dispersion to a value of from 3.5 to 4.5 and then adding to the dispersion a water-soluble compound of phosphorus in an amount of from 0.2 to 1.0% by weight expressed as P 2 O 5 and an alkaline reacting water-soluble compound of aluminium in an amount of from 0.5 to 1.5% by weight expressed as Al 2 O 3 , with all the percentages by weight being based on the weight of TiO 2 in the pigment, and adding to the dispersion a mineral acid to adjust the pH to a value of 6.5 to 8 and recovering the treated pigment.
Claim 2
Dependent Claim
240 words
A process for the treatment of titanium dioxide pigment which comprises forming an aqueous dispersion of pigmentary titanium dioxide containing a water-soluble compound of phosphorus in an amount of from 0.2 to 1.0% by weight expressed as P 2 O 5 , adding to the dispersion so formed an acidic water-soluble compound of aluminium in an amount of from 2.5 to 3.5% by weight expressed as Al 2 O 3 , a water-soluble acidic compound of zirconium in an amount of from 0.5 to 1.5% by weight expressed as ZrO 2 , an acidic water-soluble compound of titanium in an amount of from 1.5 to 3% by weight expressed as TiO 2 and a water-soluble compound of silicon in an amount of from 0.2 to 2.0% by weight expressed as SiO 2 , adjusting the pH of the dispersion to a value of from 3.5 to 4.5 and then adding to the dispersion a water-soluble compound of phosphorus in an amount of from 0.2 to 1.0% by weight expressed as P 2 O 5 and an alkaline reacting water-soluble compound of aluminium in an amount of from 0.5 to 1.5% by weight expressed as Al 2 O 3 , with all the percentages by weight being based on the weight of TiO 2 in the pigment, and adding to the dispersion a mineral acid to adjust the pH to a value of 6.5 to 8 and recovering the treated pigment.
Claim 3
Dependent Claim
21 words
A process according to claim 1 in which the aqueous dispersion of pigmentary titanium dioxide is formed from calcined titanium dioxide.
Claim 4
Dependent Claim
24 words
A process according to claim 1 in which the titanium dioxide contains at least 95% to its TiO 2 content in the rutile form.
Claim 5
Dependent Claim
30 words
A process according to claim 1 in which the titanium dioxide contains from 0.1 to 0.5% by weight Al 2 O 3 based on the weight of TiO 2 .
Claim 6
Dependent Claim
20 words
A process according to claim 1 in which the aqueous dispersion containing the water-soluble compound of phosphorus is wet milled.
Claim 7
Dependent Claim
24 words
A process according to claim 5 in which the aqueous dispersion additionally contains an alkali in sufficient amount to render the aqueous dispersion alkaline.
Claim 8
Dependent Claim
31 words
A process according to claim 5 in which the concentration of pigmentary titanium dioxide in the aqueous dispersion at the conclusion of milling is from 600 to 1000 grams per liter.
Claim 9
Dependent Claim
30 words
A process according to claim 7 in which the aqueous dispersion is diluted after wet milling to a concentration of from 150 to 250 grams per liter TiO 2 .
Claim 10
Dependent Claim
36 words
A process according to claim 1 in which the amount of the acidic water-soluble compound of aluminium added to the aqueous dispersion is from 2.8 to 3.2% by weight expressed as Al 2 O 3 .
Claim 11
Dependent Claim
15 words
A process according to claim 9 in which the acidic aluminium compound is aluminium sulphate.
Claim 12
Dependent Claim
35 words
A process according to claim 1 in which the acidic water-soluble compound of zirconium is added to the aqueous dispersion in an amount of from 0.8 to 1.2% by weight expressed as ZrO 2 .
Claim 13
Dependent Claim
34 words
A process according to claim 1 in which the acidic water-soluble compound of titanium is added to the slurry in an amount of from 1.8 to 2.4% by weight expressed as TiO 2 .
Claim 14
Dependent Claim
31 words
A process according to claim 1 in which the acidic water-soluble compounds of aluminium, titanium and zirconium are added to the aqueous dispersion in the form of a mixed aqueous solution.
Claim 15
Dependent Claim
29 words
A process according to claim 13 in which the mixed aqueous solution contains aluminium sulphate, titanyl sulphate and zirconium sulphate and has a pH of from 0.7 and 1.2.
Claim 16
Dependent Claim
30 words
A process according to claim 1 in which the water-soluble compound of silicon is added in an amount of from 0.3 to 0.7% by weight expressed as SiO 2 .
Claim 17
Dependent Claim
23 words
A process according to claim 15 in which the pH of the aqueous dispersion is then adjusted to a value of about 4.
Claim 18
Dependent Claim
54 words
A process according to claim 1 in which after the adjustment of the pH of the aqueous dispersion to a value of 3.5 to 4.5 there is added to the aqueous dispersion the water-soluble compound of phosphorus in an amount of from 0.4 to 0.7% by weight expressed as P 2 O 5 .
Claim 19
Dependent Claim
31 words
A process according to claim 1 in which the amount of the alkaline water-soluble compound of aluminium is from 0.8 to 1.2% by weight expressed as Al 2 O 3 .
Claim 20
Dependent Claim
20 words
A process according to claim 1 in which the treated pigment, after recovery, is milled in a fluid energy mill.
Claim 21
Dependent Claim
20 words
A process according to claim 19 in which the pigment is treated with an amine, alkanolamine or polyol during milling.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-03 | 1981-04-04 | 1981-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-03 | 1985-04-04 | 1985-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-03 | 1989-04-04 | 1989-10-04 | $7700.00 | Window Closed / Lapsed |