US3650757A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of inorganic salt crystals
Assignee: Fujifilm Holdings Corp
•
Filing: 1968-10-23
•
Granted: 1972-03-21
•
Expires: 1988-10-23
Abstract
Abstract An improved method for preparing crystals of a weak-soluble inorganic salt, using a double decomposition of two or more inorganic salts by simultaneously adding aqueous solutions of the inorganic salts to a dispersing medium under conditions of agitation, which comprises increasing the rate of addition of the aqueous solutions of the inorganic salts which are reacted at a rate which is proportional to, or less than, the growth rate of the surface areas of the growing crystals. Particular applicability is found wherein the salt is a silver halide and the dispersing medium is an aqueous gelatin solution.
Inventors
- 👤 Kazuo Irie
- 👤 Keiichi Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:43
CPC Classifications
G; G03; G03G; G03G5/00; G03G5/02; G03G5/04; G03G5/08; B; B01; B01D; B01D9/00; B01D9/005; B01D9/0063; G03C; G03C1/00; G03C1/005; G03C1/015
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
25 words
The method as claimed in claim 1 wherein said weak-soluble inorganic salt is a silver halide and said dispersing medium is an aqueous gelatin solution.
Claim 2
Dependent Claim
24 words
The method as claimed in claim 1 wherein said weak-soluble inorganic salt is cadmium carbonate and said dispersing medium is an aqueous gelatin solution.
Claim 3
Dependent Claim
40 words
The method of claim 1 wherein the increase in the addition rate of the aqueous solutions of the inorganic salts which are reacted is conducted continuously in proportion to the time passed since the start of the double decomposition reaction.
Claim 4
Dependent Claim
26 words
The process of claim 1 wherein said dispersing medium is a binder such as is used to form silver halide emulsion layers in the photographic art.
Claim 5
Dependent Claim
53 words
The method of claim 1 wherein said inorganic salts which are double decomposed include a silver salt and a salt which will react therewith to yield a silver halide, said dispersing medium is an aqueous gelatin solution as is used in the photographic art, and said weak-water-soluble inorganic salt is a silver halide.
Claim 6
Dependent Claim
23 words
The method of claim 6 wherein said silver salt is silver nitrate and said salt which will react therewith is an alkali halide.
Claim 7
Dependent Claim
19 words
The method of claim 3 wherein the inorganic salts which are double decomposed comprise sodium carbonate and cadmium chloride.
Claim 8
Dependent Claim
10 words
The method of claim 1 wherein said increasing is stepwise.
Claim 9
Dependent Claim
132 words
In a method of growing crystals of a weak-soluble inorganic salt wherein the solubility thereof is defined by the equation pK log 1/K > or = 4, wherein K is the dissociation constant, by the double decomposition of two or more inorganic salts by simultaneously adding aqueous solutions of the inorganic salts to a dispersing medium under conditions of agitation, the improvement which comprises: increasing the rate of addition of the aqueous solutions of the inorganic salts which are reacted to provide the crystals of the weak-soluble inorganic salts from an initial value at the beginning of crystal growth at a rate which is less than the growth rate of the surface areas of the growing crystals of the weak-soluble inorganic salt, whereby crystals having a uniform grain size are rapidly obtained.
Claim 10
Dependent Claim
40 words
The method of claim 10 wherein the increase in the addition rate of the aqueous solutions of the inorganic salts which are reacted is conducted continuously in proportion to the time passed since the start of the double decomposition reaction.
References Cited (Backward Citations)
GB787336A
Cited
DE1036637B
Cited
US2848847A
Cited
US3031304A
Cited
DE1169290B
Cited
US3415650A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |