US3895995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Film drying of hydrated alkali metal silicate solutions
Assignee: PQ Corp
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Filing: 1971-01-18
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Granted: 1975-07-22
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Expires: 1991-01-18
Abstract
Abstract Readily soluble, non-caking, hydrated alkali metal silicate particles are prepared by drying films of alkali metal silicate solutions. The conditions of dehydration, such as film thickness, temperature gradients throughout the film and the relative humidity of the air above the film are carefully controlled to obtain the product.
Inventors
- 👤 Robert W Spencer
- 👤 Newton W Mccready
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:15
CPC Classifications
B; B01; B01D; B01D1/00; B01D1/22; C; C11; C11D; C11D3/00; C11D3/02; C11D3/04; C11D3/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
143 words
IN THE KNOWN PROCESS OF DRYING AN ALKALI METAL SILICATE SOLUTION, INCLUDING CASTING A THIN FILM AND DRYING WITH HEAT TO OBTAIN AMORPHOUS PARTICLES, THE IMPROVEMENT TO SAID PROCESS INCLUDING THE CONTROL OF PROCESS CONDITIONS BY: A. MAINTAINING THE SURFACE UPON WHICH SAID FILM IS CAST AT A TEMPERATURE BETWEEN 95*C AND 136*C AND BELOW THE BOILING POINT OF THE ALKALI METAL SILICATE SOLUTION, B. MAINTAINING THE AIR SURROUNDING SAID FILM DURING THE DRYING AT 25 TO 35% RELATIVE HUMIDITY, AND C. MAINTAINING THE THICKNESS OF SAID FILM TO BE DRIED BETWEEN 0.5 AND 5.0 MILLIMETERS, WHEREBY THE PRODUCT OBTAINED FROM SAID PROCESS WILL BE EQUILIBRATED WITH RESPECT TO THE MOISTURE CONTENT, SAID MOISTURE CONTENT BEING 10 TO 30% BY WEIGHT, AND HAVE A BULK DENSITY OF 20 TO 70 LBS./CU.FT., AND THE PRODUCT HAS AN SIO2/M2O MOLE RATIO OF 1.5 TO 5.0/1.0.
Claim 2
Dependent Claim
143 words
IN THE KNOWN PROCESS OF DRYING AN ALKALI METAL SILICATE SOLUTION, INCLUDING CASTING A THIN FILM AND DRYING WITH HEAT TO OBTAIN AMORPHOUS PARTICLES, THE IMPROVEMENT TO SAID PROCESS INCLUDING THE CONTROL OF PROCESS CONDITIONS BY: A. MAINTAINING THE SURFACE UPON WHICH SAID FILM IS CAST AT A TEMPERATURE BETWEEN 95*C AND 136*C AND BELOW THE BOILING POINT OF THE ALKALI METAL SILICATE SOLUTION, B. MAINTAINING THE AIR SURROUNDING SAID FILM DURING THE DRYING AT 25 TO 35% RELATIVE HUMIDITY, AND C. MAINTAINING THE THICKNESS OF SAID FILM TO BE DRIED BETWEEN 0.5 AND 5.0 MILLIMETERS, WHEREBY THE PRODUCT OBTAINED FROM SAID PROCESS WILL BE EQUILIBRATED WITH RESPECT TO THE MOISTURE CONTENT, SAID MOISTURE CONTENT BEING 10 TO 30% BY WEIGHT, AND HAVE A BULK DENSITY OF 20 TO 70 LBS./CU.FT., AND THE PRODUCT HAS AN SIO2/M2O MOLE RATIO OF 1.5 TO 5.0/1.0.
Claim 3
Dependent Claim
26 words
The process of claim 1 wherein the alkali metal silicate solution is selected from the group consisting of sodium silicate, potassium silicate, and sodium-potassium double silicates.
Claim 4
Dependent Claim
22 words
The process of claim 1 wherein the film is dried to a moisture content of 18 to 27% on a weight basis.
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) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |