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US4272293A
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Procedure for the treatment of combined wet filter cakes
Assignee: Pelt and Hooykaas BV
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Filing: 1978-07-17
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Granted: 1981-06-09
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Expires: 1998-07-17
Abstract
Abstract A procedure for the treatment of filter cakes obtained during the purification of chemical substances in liquid form, especially during the purification of phosphoric acid obtained by wet methods, whereby a filter cake is dried and heated in the presence of a melt of inorganic material.
Inventors
- 👤 Carel W. J. Hooykaas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:19
CPC Classifications
B; B01; B01J; B01J6/00; B01J6/005; C; C02; C02F; C02F11/00; C02F11/008; C03; C03C; C03C1/00; C03C1/002; E; E01; E01C; E01C7/00; E01C7/08; E01C7/085
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
48 words
In a process for the treatment of metal-containing filter cakes formed during the purification of wet phosphoric acid obtained by wet methods, the improvement comprising heating the filter cake to above 500° C. in the presence of an inorganic melt whereby said metals are absorbed in the melt.
Claim 2
Dependent Claim
48 words
In a process for the treatment of metal-containing filter cakes formed during the purification of wet phosphoric acid obtained by wet methods, the improvement comprising heating the filter cake to above 500° C. in the presence of an inorganic melt whereby said metals are absorbed in the melt.
Claim 3
Dependent Claim
16 words
The process of claim 1, wherein the melt is formed by heating a dried filter cake.
Claim 4
Dependent Claim
18 words
The process of claim 1, wherein a filter cake is dried and added to molten metallurgical slag material.
Claim 5
Dependent Claim
12 words
The process of claim 1 wherein the filter cake contains silicate compounds.
Claim 6
Dependent Claim
27 words
The process of claim 1 wherein the filter cake contains disodium phosphate, sodium aluminium silicate, ferric hydroxide, magnesium silicate, calcium fluoride, chromium trioxide, zinc oxide and carbon.
Claim 7
Dependent Claim
19 words
The process of claim 1 wherein the filter cake consists mainly of disodium phosphate, ferric hydroxide and magnesium fluoride.
Claim 8
Dependent Claim
11 words
The process of claim 6, wherein the filter cake contains vanadium.
Claim 9
Dependent Claim
16 words
The process of claim 1 wherein a plurality of said filter cakes are mixed before heating.
Claim 10
Dependent Claim
38 words
The process of claim 8 wherein an initial dry gypsum-containing filter cake obtained by purification is mixed with at least one of a dried second and a third filter cake, all of which is heated until melting occurs.
Claim 11
Dependent Claim
33 words
The process of claim 9, wherein at least equal parts of a dried initial filter cake are mixed with equal parts of at least one of a dried second and third filter cake.
Claim 12
Dependent Claim
29 words
The process of claim 9, wherein a dried gypsum-containing initial filter cake is mixed with an excess of at least one of a dried second and third filter cake.
Claim 13
Dependent Claim
31 words
The process of claim 10, wherein two parts of a dried initial filter cake being mixed with three parts of at least one of a dried second and third filter cake.
Claim 14
Dependent Claim
31 words
The process of claim 9, wherein a liquid filter cake is obtained and is kept in motion so as to give the carbon present in the cake an opportunity to escape.
Claim 15
Dependent Claim
14 words
The process of claim 10, wherein non-skid-enhancing stabilizers are added to the melt obtained.
Claim 16
Dependent Claim
13 words
The process of claim 14, wherein said non-skid-enhancing stabilizers consist of sand particles.
Claim 17
Dependent Claim
16 words
The process of claim 14, wherein corundum particles are added to the melt as non-skid-enhancing stabilizers.
Claim 18
Dependent Claim
12 words
The process of claim 1 wherein the resultant melt is broken up.
Claim 19
Dependent Claim
37 words
The process of claim 9, wherein a second filter cake contains sodium phosphate, sodium aluminium, iron hydroxide, magnesium silicate, calcium fluoride, chromium trioxide, zinc oxide, titanium, cadmium, manganese, vanadium, mercury, lead, rare earth metals, uranium and/or carbon.
Claim 20
Dependent Claim
33 words
The process of claim 9 wherein a third filter cake consists of disodium phosphate, ferric hydroxide, magnesium fluoride, which may comprise vanadium pentoxide, titanium, cadmium, manganese, chromium, mercury, lead, lanthanum, uranium and/or carbon.
Claim 21
Dependent Claim
33 words
The process of claim 1, wherein the initial filter cake consists of 80-85% gypsum and the remainder of small quantities of other metals such as iron, aluminium, magnesium, chromium, vanadium, copper and carbon.
Claim 22
Dependent Claim
21 words
The process of claim 1 wherein the melt is formed by heating above 500° C. materials present in the filter cake.
Claim 23
Dependent Claim
23 words
The process of claim 21 wherein the meltable materials present in the filter cake are melted down completely between 700° and 1000° C.
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) | 1984-06-08 | 1984-12-08 | 1985-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-08 | 1988-12-08 | 1989-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-08 | 1992-12-08 | 1993-06-09 | $7700.00 | Window Closed / Lapsed |