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US4451388A Expired / Lapsed US ⏱️ 0.0 years remaining

Preparation of aluminum oxide coated silica sols using ultrafiltration

Assignee: ChampionX LLC
•
Filing: 1981-11-02
•
Granted: 1984-05-29
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Expires: 2001-11-02
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Abstract

Abstract New alumina coated silica sols are produced by a method which comprises mixing a concentrated deionized silica sol with concentrated solutions of trivalent acid aluminum salts, heating this premix to at least 90 DEG C. for 1-15 minutes to form an alumina reacted silica sol solution, cooling this reacted silica sol solution to form a cooled alumina reacted silica sol solution, diluting with deionized water to about 10 weight percent solids, exposing this diluted alumina reacted silica sol to ultrafiltration through a membrane having a molecular weight cutoff of about 30,000, adding distilled or deionized water to the diluted alumina reacted silica sol during ultrafiltration to wash dissolved salts from this salt solution forming a diluted alumina-coated silica sol having a pH between about 4-5 and a conductivity between about 2,000-4,000 micromhos, concentrating this dilute alumina-coated silica sol to at least 30 weight percent solids, thereby obtaining a stable alumina-coated silica sol.

Inventors

  • 👤 Charles C. Payne

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 08:09
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/146; C01B33/149

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 194 words
A method of producing alumina coated silica sols which comprises: A. Mixing a concentrated deionized silica sol with a concentrated solution of trivalent acidic aluminum salts to obtain a premix, B. Heating this premix to at least 90° C. for from 1 to 15 minutes to form an alumina reacted silica sol solution, C. Cooling this alumina reacted silica sol solution to at least 180° F. to form a cooled alumina reacted silica sol solution, D. Diluting this cooled alumina reacted silica sol solution with deionized water to about 10 weight percent solids to form a diluted alumina reacted silica sol, E. Exposing the diluted alumina reacted silica sol to ultrafiltration through a membrane having a molecular weight cutoff of about 30,000, and F. Adding distilled or deionized water to the diluted alumina reacted silica sol during step E to wash dissolved salts from said diluted alumina reacted silica sol to form a dilute alumina coated silica sol having a pH from about 4-5 and a conductivity of from 2000-4000 micromhos, and G. Concentrating this dilute alumina coated silica sol to at least 30 weight percent solids, thereby obtaining said alumina coated silica sols.
Claim 2
Independent Claim 194 words
A method of producing alumina coated silica sols which comprises: A. Mixing a concentrated deionized silica sol with a concentrated solution of trivalent acidic aluminum salts to obtain a premix, B. Heating this premix to at least 90° C. for from 1 to 15 minutes to form an alumina reacted silica sol solution, C. Cooling this alumina reacted silica sol solution to at least 180° F. to form a cooled alumina reacted silica sol solution, D. Diluting this cooled alumina reacted silica sol solution with deionized water to about 10 weight percent solids to form a diluted alumina reacted silica sol, E. Exposing the diluted alumina reacted silica sol to ultrafiltration through a membrane having a molecular weight cutoff of about 30,000, and F. Adding distilled or deionized water to the diluted alumina reacted silica sol during step E to wash dissolved salts from said diluted alumina reacted silica sol to form a dilute alumina coated silica sol having a pH from about 4-5 and a conductivity of from 2000-4000 micromhos, and G. Concentrating this dilute alumina coated silica sol to at least 30 weight percent solids, thereby obtaining said alumina coated silica sols.
Claim 3
Dependent Claim 42 words
The method of claim 1 wherein the concentrated deionized silica sol contains 25.5 weight percent silica, has a pH of 3.0±0.3 units, has a particle size between 15 and 25 millimicrons, and a surface area of about 150 m 2 per gram.
Claim 4
Dependent Claim 22 words
The method of claim 2 wherein the concentrated solution of trivalent acidic aluminum salts contains about 25 weight percent aluminum hydroxy dichloride.
Claim 5
Dependent Claim 12 words
The alumina coated silica sol synthesized by the method of claim 1.
Claim 6
Dependent Claim 14 words
The alumina coated silica sol synthesized by the method of claims 2 or 3.

References Cited (Backward Citations)

US3560400A Cited
US3864142A Cited
US3969266A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-05-29 1987-11-28 1988-05-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-05-29 1991-11-28 1992-05-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-05-29 1995-11-28 1996-05-29 $7700.00 Window Closed / Lapsed

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