US4186027A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing of kaolinitic clays at high solids
Assignee: Imerys Minerals Ltd
•
Filing: 1978-05-30
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Granted: 1980-01-29
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Expires: 1998-05-30
Abstract
Abstract A process for treating a clay mineral of the kandite group comprising forming a fluid aqueous suspension of the clay mineral, the suspension having a solids content in the range of from 60% to 75% by weight and a pH in the range of from 7.0 to 11.0 and the suspension containing a dispersing agent to deflocculate the clay mineral; and treating the fluid suspension of clay containing the dispersing agent with a water-soluble reducing bleaching agent under alkaline pH conditions for a time sufficient to give the desired improvement in brightness of the clay. Preferably, the clay mineral suspension is subjected to a particle size separation process at said solids content to reduce the percentage of particles larger than 10 mu m to not more than 3% by weight. Advantageously, the viscosity of the clay mineral suspension during the particle size separation process is below 2 poise.
Inventors
- 👤 David G. Bell
- 👤 Keith R. Gibson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:25
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/40; C09C1/42; D; D21; D21H; D21H19/00; D21H19/36; D21H19/38; D21H19/40; C01; C01P; C01P2002/00; C01P2002/80; C01P2002/84; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/22; C01P2006/60; C01P2006/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
189 words
A process for treating a raw kaolinitic clay mineral which comprises forming a fluid aqueous suspension of the kaolinitic clay mineral, said suspension having a solids content in the range of from about 60% to about 75% by weight and a pH in the range of from 7.5 to 10.5 and said suspension containing from 0.05 to 0.6% by weight of the dry clay of a dispersing agent system comprising from 2.5 to 7 parts by weight of a water-soluble condensed phosphate to 1 part by weight of a water-soluble organic polymeric dispersing agent; subjecting said suspension to a particle size separation technique at a temperature such that the viscosity thereof is less than 2 poise to reduce the percentage by weight of the particles larger than 10 μm in said suspension to not more than 3% by weight; and treating said 60% to 75% solids suspension with a water-soluble reducing bleaching agent at an alkaline pH in the range of pH 7.5 to 10.5 for a time sufficient to increase the brightness of the clay mineral, said process being carried out without the necessity for dewatering said suspension.
Claim 2
Dependent Claim
189 words
A process for treating a raw kaolinitic clay mineral which comprises forming a fluid aqueous suspension of the kaolinitic clay mineral, said suspension having a solids content in the range of from about 60% to about 75% by weight and a pH in the range of from 7.5 to 10.5 and said suspension containing from 0.05 to 0.6% by weight of the dry clay of a dispersing agent system comprising from 2.5 to 7 parts by weight of a water-soluble condensed phosphate to 1 part by weight of a water-soluble organic polymeric dispersing agent; subjecting said suspension to a particle size separation technique at a temperature such that the viscosity thereof is less than 2 poise to reduce the percentage by weight of the particles larger than 10 μm in said suspension to not more than 3% by weight; and treating said 60% to 75% solids suspension with a water-soluble reducing bleaching agent at an alkaline pH in the range of pH 7.5 to 10.5 for a time sufficient to increase the brightness of the clay mineral, said process being carried out without the necessity for dewatering said suspension.
Claim 3
Dependent Claim
21 words
A process according to claim 1, wherein the fluid suspension contains from about 68% to about 72% by weight of solids.
Claim 4
Dependent Claim
29 words
A process according to claim 1, wherein the fluid suspension of clay is treated with the water-soluble reducing bleaching agent at a pH in the range 8.5 to 9.5.
Claim 5
Dependent Claim
40 words
A process according to claim 1, wherein the water-soluble reducing bleaching agent is sodium or zinc dithionite which is employed in an amount in the range of from 1 to 15 lb. of bleaching agent per ton of dry clay.
Claim 6
Dependent Claim
43 words
A process according to claim 1, wherein the clay suspension is agitated sufficiently rapidly to cause a vortex while the bleaching agent is added thereto but when the bleaching agent has been added the degree of agitation is reduced until the vortex collapses.
Claim 7
Dependent Claim
35 words
A process according to claim 1, wherein the clay suspension is maintained at a temperature in the range of from 30° C. to 65° C. whilst it is subjected to said particle size separation technique.
Claim 8
Dependent Claim
63 words
A process according to claim 1, wherein the clay suspension is maintained at a temperature such that the viscosity of the clay suspension is less than 2 poise by passing the suspension through a heat exchanger, by immersing steam coils or electric heaters in the suspension, by heating the container for the clay suspension or by blowing steam directly into the clay suspension.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-28 | 1983-07-30 | 1984-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-28 | 1987-07-30 | 1988-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-28 | 1991-07-30 | 1992-01-29 | $7700.00 | Window Closed / Lapsed |