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US4002484A
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Process for the manufacture of a fine white filler for industrial purposes
Assignee: LafargeHolcim Ciments SA
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Filing: 1973-11-09
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Granted: 1977-01-11
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Expires: 1993-11-09
Abstract
Abstract A substantially stoichiometric mixture of calcic aluminate and calcium sulphate, as white as possible, formed at a temperature in the range of about 20° to 90° C, is hydrated simultaneously; water is added at least in stoichiometric proportions for the reaction and at a maximum in an amount such that after the reaction a product is obtained containing 5% (dry) ettringite and 95% (by weight) water, stoichiometry being defined, for example by the reaction CaO,Al.sub.2 O.sub.3 + (CaO, H.sub.2 O) + 3(CaSO.sub.4, 2H.sub.2 O) + 24 H 2 O→(CaO) 3 , Al 2 O 3 , 3 CaSO 4 , 32 H 2 O (ettringite) It is thus possible to obtain in an economical and very flexible manner, ettringite, or suspensions containing same, for all industrial uses, notably for paper-making.
Inventors
- 👤 Jacques Baudouin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:20
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/68; C01F7/74; C01F7/76; C01F7/767; C09; C09C; C09C1/00; C09C1/40; C09C1/402; C01P; C01P2004/00; C01P2004/51; C01P2006/00; C01P2006/12; C01P2006/19; C01P2006/60
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
208 words
A process for preparing ettringite or calcium trisulfoaluminate (3 CaO .sup.. Al 2 O 3 .sup.. 3CaSO 4 .sup.. 32 H 2 O) according to a reaction depicted by at least one of the following reaction schemes: a. CaO.sup.. Al.sub.2 O.sub.3 + 2(CaO.sup.. H.sub.2 O) + 3(CaSO.sub.4.sup.. 2H.sub.2 O) + 24H.sub.2 O → ettringite b. (CaO).sub.3 Al.sub.2 O.sub.3 + 3(CaSO.sub.4.sup.. 2H.sub.2 O) + 26 H.sub.2 O → ettringite c. CaO(Al.sub.2 O.sub.3).sub.2 + 5(CaO.sup.. H.sub.2 O) + 6(CaSO.sub.4.sup.. 2H.sub.2 O) + 47H.sub.2 O → 2 ettringite d. 12 CaO.sup.. 7Al.sub.2 O.sub.3 + 9(CaO.sup.. H.sub.2 O) + 21(CaSO.sub.4.sup.. 2H.sub.2 O) + 173H.sub.2 O → 7 ettringite e. CaO.sup.. 6Al.sub.2 O.sub.3 + 17(CaO.sup.. H.sub.2 O) + 18(CaSO.sub.4.sup.. 2H.sub.2 O) + 139H.sub.2 O → 6 ettringite which comprises forming a substantially stoichiometric mixture of calcic aluminate and calcium sulfate in an amount of water which is at least a stoichiometric proportion and at most sufficient to yield a product containing 5 percent by weight of (dry) ettringite and 95 percent by weight of water, and effecting reaction at a temperature in the range of from 20° to 90° C; the calcium sulfate having as white a color as possible, and the stoichiometric mixture and the stoichiometric proportion being based on the reaction.
Claim 2
Dependent Claim
208 words
A process for preparing ettringite or calcium trisulfoaluminate (3 CaO .sup.. Al 2 O 3 .sup.. 3CaSO 4 .sup.. 32 H 2 O) according to a reaction depicted by at least one of the following reaction schemes: a. CaO.sup.. Al.sub.2 O.sub.3 + 2(CaO.sup.. H.sub.2 O) + 3(CaSO.sub.4.sup.. 2H.sub.2 O) + 24H.sub.2 O → ettringite b. (CaO).sub.3 Al.sub.2 O.sub.3 + 3(CaSO.sub.4.sup.. 2H.sub.2 O) + 26 H.sub.2 O → ettringite c. CaO(Al.sub.2 O.sub.3).sub.2 + 5(CaO.sup.. H.sub.2 O) + 6(CaSO.sub.4.sup.. 2H.sub.2 O) + 47H.sub.2 O → 2 ettringite d. 12 CaO.sup.. 7Al.sub.2 O.sub.3 + 9(CaO.sup.. H.sub.2 O) + 21(CaSO.sub.4.sup.. 2H.sub.2 O) + 173H.sub.2 O → 7 ettringite e. CaO.sup.. 6Al.sub.2 O.sub.3 + 17(CaO.sup.. H.sub.2 O) + 18(CaSO.sub.4.sup.. 2H.sub.2 O) + 139H.sub.2 O → 6 ettringite which comprises forming a substantially stoichiometric mixture of calcic aluminate and calcium sulfate in an amount of water which is at least a stoichiometric proportion and at most sufficient to yield a product containing 5 percent by weight of (dry) ettringite and 95 percent by weight of water, and effecting reaction at a temperature in the range of from 20° to 90° C; the calcium sulfate having as white a color as possible, and the stoichiometric mixture and the stoichiometric proportion being based on the reaction.
Claim 3
Dependent Claim
22 words
A process according to claim 1 wherein hydration is effected at a temperature in the range of from 25° to 60° C.
Claim 4
Dependent Claim
15 words
A process according to claim 1 wherein the reaction comprises that of reaction scheme (a).
Claim 5
Dependent Claim
15 words
A process according to claim 1 wherein the reaction comprises that of reaction scheme (b).
Claim 6
Dependent Claim
15 words
A process according to claim 1 wherein the reaction comprises that of reaction scheme (c).
Claim 7
Dependent Claim
15 words
A process according to claim 1 wherein the reaction comprises that of reaction scheme (d).
Claim 8
Dependent Claim
15 words
A process according to claim 1 wherein the reaction comprises that of reaction scheme (e).
Claim 9
Dependent Claim
24 words
A process according to claim 1 which comprises adding sufficient anhydrous or hydrated lime to the mixture to satisfy the stoichiometric requirement for clacium.
Claim 10
Dependent Claim
45 words
A process according to claim 1 wherein the calcic aluminate is at least one member selected from the group consisting of 3CaO.sup.. Al 2 O 3 , 12CaO.sup.. 7Al 2 O 3 , CaO.sup.. 2Al 2 O 3 and CaO.sup.. 6Al 2 O 3 .
Claim 11
Dependent Claim
45 words
A process according to claim 1 wherein the calcium sulfate is at least one member selected from the group consisting of gypsum (CaSO 4 .sup.. 2H 2 O), semihydrate (CaSO 4 .sup.. 1/2 H 2 O), "soluble" anhydride, "overburnt" anhydrous CaSO 4 and natural anhydrite.
Claim 12
Dependent Claim
23 words
A process according to claim 1 wherein the calcium sulfate comprises natural carbonated calcium sulfate containing at least 60 percent pure calcium sulfate.
Claim 13
Dependent Claim
21 words
A process according to claim 1 which comprises adding to the mixture carbonated hydrated lime containing less than 40 percent carbonate.
Claim 14
Dependent Claim
21 words
A process according to claim 1 wherein amounts of respective reactants do not vary more than 20 percent from stoichiometric requirements.
Claim 15
Dependent Claim
15 words
A process according to claim 1 wherein reactants comprise refractory alumina cement, gypsum and lime.
Claim 16
Dependent Claim
54 words
A process according to claim 1 which comprises adding to the mixture an excess of from about 50 to 1900 parts by weight of water per 100 parts by weight of ettringite to be prepared, maintaining the mixture in suspension during reaction, and using thus-prepared ettringite in the suspension in which it is formed.
Claim 17
Dependent Claim
53 words
A process according to claim 1 which comprises adding to the mixture an excess of from about 50 to 1900 parts by weight of water per 100 parts by weight of ettringite to be prepared, maintaining the mixture in suspension during reaction, drying thus-prepared ettringite, and recovering the resulting product in powder form.
Claim 18
Dependent Claim
14 words
A process according to claim 1 wherein the aluminate is in finely divided form.
Claim 19
Dependent Claim
45 words
A process according to claim 1 wherein the mixture of calcic aluminate and calcium sulfate further contains calcium silicate in an amount corresponding to a final product having from 80 to 90% by weight of ettringite and from 20 to 10% by weight of tobermorite.
Claim 20
Dependent Claim
40 words
A process according to claim 18 which comprises hydrating calcium silicate, calcium aluminate and calcium sulfate to form a mixture comprising from 80 to 90 percent by weight of ettringite and from 20 to 10 percent by weight of Tobermorites.
Claim 21
Dependent Claim
28 words
A process according to claim 19 wherein the calcium silicate comprises Portland cement, the calcium aluminate comprises refractory alumina cement, and the calcium sulfate comprises powdered quarry gypsum.
Claim 22
Dependent Claim
35 words
A process according to claim 19 which comprises mixing primary hydrate, obtained by hydrating the silicate, with calcium aluminate and with calcium sulfate, the primary hydrate being in a proportion based on available calcium aluminate.
Claim 23
Dependent Claim
41 words
A process according to claim 18 which comprises simultaneously hydrating calcium silicate, calcium aluminate and calcium sulfate to form a mixture comprising from 80 to 90 percent by weight of ettringite and from 20 to 10 percent by weight of Tobermorites.
Claim 24
Dependent Claim
15 words
A process according to claim 1 wherein the calcium sulfate is a synthetic industrial by-product.
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) | 1980-01-11 | 1980-07-12 | 1981-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-11 | 1984-07-12 | 1985-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-11 | 1988-07-12 | 1989-01-11 | $7700.00 | Window Closed / Lapsed |