US3840348A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crystallizing alkali metal contact with silicate droplets in countercurrent air flow
Assignee: PQ Corp
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Filing: 1971-05-10
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Granted: 1974-10-08
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Expires: 1991-05-10
Abstract
Abstract Readily soluble crystalline alkali metal silicates with improved physical properties are prepared by forming drops of liquor that will crystallize into the desired species in a prilling tower so that crystallization can take place as the drops fall through the tower. If crystallization is not complete when the particles are exhausted from the tower it can be completed in a fluid bed. More specifically this invention is directed toward the production of sodium metasilicate hydrates and particularly the pentahydrate.
Inventors
- 👤 E Vessey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:02
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/20; C01B33/32; C01B33/325; B; B01; B01D; B01D9/00; B01D9/0004; B01D9/0009; B01D9/0036; B01J; B01J2/00; B01J2/02; B01J2/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
151 words
A PROCESS FOR PREPARING GRANULES OF CRYSTALLIZED ALKALI METAL SILICATE PARTICLES SELECTED FROM THE GROUP CONSISTING OF SODIUM METASILICATE AND SODIUM SESQUISILICATE FROM A SODIUM SILICATE LIQUOR HAVING THE DESIRED NA2O/SIO2 MOLE RATIO OF THE PRODUCT COMPRISING THE STEPS OF: A. COOLING THE LIQUID TO BELOW ITS MELTING POINT, B. ADMIXING WITH THE LIQUOR 2 TO 15 PERCENT OF FINE SEED PARTICLES HAVING THE COMPOSITION OF THE PRODUCT, C. ATOMIZING THE SEEDED LIQUOR AS FALLING DROPLETS INTO THE TOP OF A PRILLING TOWER, D. ADJUSTING RESIDENCE TIME OF THE FALLING DROPLETS IN THE PRILLING TOWER VELOCITY OF COUNTERCURRENT AIR FLOW, E. DISSIPATING THE HEAT OF CRYSTALLIZATION FROM THE ATOMIZED LIQUOR DROPLETS WITH AN UPWARD FLOW OF AIR MAINTAINED AT 10* TO 40*C BELOW THE MELTING POINT OF THE CRYSTALLINE SPECIE, F. SIMULTANEOUSLY CRYSTALLIZING THE DROPLETS OF LIQUOR, AND G. EXHAUSTING THE DESIRED CRYSTALLIZING GRANULES FROM THE BOTTOM OF THE PRILLING TOWER.
Claim 2
Dependent Claim
151 words
A PROCESS FOR PREPARING GRANULES OF CRYSTALLIZED ALKALI METAL SILICATE PARTICLES SELECTED FROM THE GROUP CONSISTING OF SODIUM METASILICATE AND SODIUM SESQUISILICATE FROM A SODIUM SILICATE LIQUOR HAVING THE DESIRED NA2O/SIO2 MOLE RATIO OF THE PRODUCT COMPRISING THE STEPS OF: A. COOLING THE LIQUID TO BELOW ITS MELTING POINT, B. ADMIXING WITH THE LIQUOR 2 TO 15 PERCENT OF FINE SEED PARTICLES HAVING THE COMPOSITION OF THE PRODUCT, C. ATOMIZING THE SEEDED LIQUOR AS FALLING DROPLETS INTO THE TOP OF A PRILLING TOWER, D. ADJUSTING RESIDENCE TIME OF THE FALLING DROPLETS IN THE PRILLING TOWER VELOCITY OF COUNTERCURRENT AIR FLOW, E. DISSIPATING THE HEAT OF CRYSTALLIZATION FROM THE ATOMIZED LIQUOR DROPLETS WITH AN UPWARD FLOW OF AIR MAINTAINED AT 10* TO 40*C BELOW THE MELTING POINT OF THE CRYSTALLINE SPECIE, F. SIMULTANEOUSLY CRYSTALLIZING THE DROPLETS OF LIQUOR, AND G. EXHAUSTING THE DESIRED CRYSTALLIZING GRANULES FROM THE BOTTOM OF THE PRILLING TOWER.
Claim 3
Dependent Claim
27 words
The process of claim 1 in which the alkali metal silicate liquor contains 3 to 15 percent excess water based on the weight of the silicate solids.
Claim 4
Dependent Claim
15 words
The process of claim 1 in which the seed particles are finer than 100 mesh.
Claim 5
Dependent Claim
15 words
The process of claim 1 in which the seed particles are finer than 325 mesh.
Claim 6
Dependent Claim
23 words
The process of claim 1 in which the seeded alkali metal silicate liquor is atomized with a pressure nozzle or an atomizer wheel.
Claim 7
Dependent Claim
22 words
The process of claim 1 in which the air flowing up the prilling tower has a velocity between 25 and 500 ft/min.
Claim 8
Dependent Claim
16 words
The process of claim 1 in which the air flowing up the prilling tower is humidified.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |