Patent US3893841A successfully refreshed from Google Patents.
US3893841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bone china
Assignee: Doulton and Co Ltd
•
Filing: 1973-10-02
•
Granted: 1975-07-08
•
Expires: 1993-10-02
Abstract
Abstract A substitute for bone ash suitable for the complete or partial replacement of bone ash in the manufacture of bone china (English porcelain) is obtained by the calcination of a mixture of a calcium phosphate and calcium oxide or a precursor thereof at an elevated temperature to give a sintered product of relatively low surface area and the grinding of said sintered product to form a particulate substance having the required characteristics for use as a bone ash substitute.
Inventors
- 👤 Krishan Kumar Nijhawan
- 👤 Derek Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:02
CPC Classifications
C; C04; C04B; C04B33/00; C04B33/24; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/32
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
134 words
A SYNTHETIC BONE ASH SUBSTITUTE SUITABLE FOR USE AS A COMPLETE OR PARTIAL REPLACEMENT FOR BONE ASH IN THE MANUFACTURE OF BONE CHINA BY CONVENTIONAL POTTERY METHODS, BEING THE PRODUCT OBTAINABLE BY (A) PRODUCING A MIXTURE CONSTISTING ESSENTIALLY OF A CALCIUM PHOSPHATE AND A CALCIUM SUBSTANCE SELECTED FROM CALCIUM OXIDE AND COMPOUNDS WHICH ON HEATING DECOMPOSE TO FORM CALCIUM OXIDE, SAID CACIUM PHOSPHATE AND SAID CALCIUM SUBSTANCE BEING MIXED IN POPORTIONS SUCH THAT AFTER THE SUBSEQUENT CALCINING STEP (B), THE CA: P RATIO LIE IN THE RANGE OF FROM 1:1 TO 2:1 (B) CALCINING SAID MIXTURE AT A TEMPERATURE OF AT LEAST 900*C SO AS TO FORM A SINTERED PRODUCT HVING A SURFACE AREA OF LESS THAN 5 M.2G. -1, AND (C) GRINDING THE RESULTING SINTERED PRODUCT TO A MEAN PARTICLE SIZE IN THE
Claim 2
Dependent Claim
134 words
A SYNTHETIC BONE ASH SUBSTITUTE SUITABLE FOR USE AS A COMPLETE OR PARTIAL REPLACEMENT FOR BONE ASH IN THE MANUFACTURE OF BONE CHINA BY CONVENTIONAL POTTERY METHODS, BEING THE PRODUCT OBTAINABLE BY (A) PRODUCING A MIXTURE CONSTISTING ESSENTIALLY OF A CALCIUM PHOSPHATE AND A CALCIUM SUBSTANCE SELECTED FROM CALCIUM OXIDE AND COMPOUNDS WHICH ON HEATING DECOMPOSE TO FORM CALCIUM OXIDE, SAID CACIUM PHOSPHATE AND SAID CALCIUM SUBSTANCE BEING MIXED IN POPORTIONS SUCH THAT AFTER THE SUBSEQUENT CALCINING STEP (B), THE CA: P RATIO LIE IN THE RANGE OF FROM 1:1 TO 2:1 (B) CALCINING SAID MIXTURE AT A TEMPERATURE OF AT LEAST 900*C SO AS TO FORM A SINTERED PRODUCT HVING A SURFACE AREA OF LESS THAN 5 M.2G. -1, AND (C) GRINDING THE RESULTING SINTERED PRODUCT TO A MEAN PARTICLE SIZE IN THE
Claim 3
Dependent Claim
22 words
A bone ash substitute as claimed in claim 1, wherein the Ca:P ratio lies in the range of from 1.5:1 to 1.75:1.
Claim 4
Dependent Claim
27 words
A bone ash substitute as claimed in claim 1, wherein the calcining step (b) is effected at a temperature in the range of from 900* to 1,200*C.
Claim 5
Dependent Claim
21 words
A bone ash substitute as claimed in claim 1, wherein the sintered product has a surface area below 1.0 m.2g. 1.
Claim 6
Dependent Claim
33 words
A bone ash substitute as claimed in claim 1, wherein the sintered product is ground in step (c) to a mean particle size in the range of from 2.5 to 3.0 Mu m.
Claim 7
Dependent Claim
24 words
A bone ash substitute as claimed in claim 1, wherein the calcium phosphate is dicalcium phosphate dihydrate and the calcium substance is calcium carbonate.
Claim 8
Dependent Claim
28 words
A bone ash substitute as claimed in claim 1, wherein after step (c) ground limestone is blended with said required product in order to increase the Ca:P ratio.
Claim 9
Dependent Claim
15 words
Bone china comprising china clay, cornish stone and the bone ash substitute of claim 1.
References Cited (Backward Citations)
US2263656A
Cited
US3241935A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-07 | 1979-01-06 | 1979-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-07 | 1983-01-06 | 1983-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-07 | 1987-01-06 | 1987-07-08 | $7700.00 | Window Closed / Lapsed |