PROCESS FOR MANUFACTURING A RAPID HARDENING PORTLAND CEMENT

• US 3,819,389 A
• Filed: 11/27/1972
• Issued: 06/25/1974
• Est. Priority Date: 11/26/1971
• Status: Expired due to Term

• Current Assignee: Hiroshi Uchikawa, Noboru Kasai
• Original Assignee: Hiroshi Uchikawa, Noboru Kasai
• Inventors: Uchikawa, Hiroshi, Kasai, Noboru
• Primary Examiner(s): Poer, James E.
• Application Number:
  US05/309,805
• Time in Patent Office: 575 Days
• Field of Search: 106/314,315,89,100,104
• US Class Current: 106/734
• CPC Class Codes: C04B 7/00 Hydraulic cements calcium sulfate cements C04B11/00

Abstract

This invention relates to a process for manufacturing a modified rapid hardening portland cement of which a setting time is convenient even at low temperature, which comprises mixing calcium carbonate, sodium carbonate, potassium carbonate and/or magnesium carbonate, or a mixture of said carbonate and sodium sulfate, potassium sulfate, aluminium sulfate and/or magnesium sulfate with a clinker which mainly consists of a calcium haloaluminate having the formula 11CaO.7Al2O3.CaX2, intergrinding the mixture and then mixing finely powdered anhydrite with the ground mixture to manufacture cement in an amount such that the weight ratio of Al2O3/SO3 in the cement is 0.6-1.8.

Claims

2. A process claimed in claim 1, wherein the clinker comprises 5-60 percent by weight of 11CaO.7Al2O3.CaX2.

3. A process claimed in claim 1, wherein the fineness of the interground mixture of the clinker and the carbonate is 2,500-8, 500 cm2/g Blaine specific surface area.

4. A process claimed in claim 3, wherein the fineness of the interground mixture is 4,000-6,500 cm2/g Blaine specific surface area.

5. A process claimed in claim 1, wherein the carbonate is mixed with the clinker in the amount of 1-15 percent.

6. A process claimed in claim 1, wherein the fiNeness of anhydrite powder is 2,500-15,000 cm/g Blaine specific surface area.

7. A process claimed in claim 6, wherein the fineness of anhydrite powder is 5,000-10,000 cm2/g Blaine specific surface area.

8. A process claimed in claim 1, wherein the fineness of anhydrite powder mixed with the interground mixture is lowered as the fineness of the interground mixture is decreased.

9. A process claimed in claim 1, wherein X is fluorine.

10. A process claimed in claim 1, wherein at least one sulfate selected from the group consisting of sodium sulfate, potassium sulfate, aluminium sulfate and magnesium sulfate is mixed besides the carbonate.

11. A process claimed in claim 10, wherein the clinker comprises 5-60 percent by weight of 11CaO.7Al2O3.CaX2.

12. A process claimed in claim 10, wherein the sulfate is mixed with the clinker in the amount of 0.1-7.0 percent.

13. A process claimed in claim 10, wherein the fineness of anhydrite is 2,500-15,000 cm2/g Blaine specific surface area.

14. A process claimed in claim 10, wherein the fineness of anhydrite added to the interground mixture is lowered as the fineness of the interground mixture is decreased.

15. A process claimed in claim 10, wherein X is fluorine.