PRODUCTION OF CEMENT ADDITIVES FROM COMBUSTION PRODUCTS OF HYDROCARBON FUELS AND STRENGTH ENHANCING METAL OXIDES

• US 20110067601A1
• Filed: 09/23/2010
• Published: 03/24/2011
• Est. Priority Date: 09/24/2009
• Status: Active Grant

• Current Assignee: Ash Improvement Technology Inc.
• Original Assignee: Ash Improvement Technology Inc.
• Inventors: Fried, Wayne
• Granted Patent: US 8,741,054 B2
• Time in Patent Office: Days
• US Class Current: 106/705
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 14/22 Glass ; Devitrified glass
• CPC Class Codes: C04B 14/28 of calcium
• CPC Class Codes: C04B 18/023 Fired or melted materials
• CPC Class Codes: C04B 18/06 Combustion residues, e.g. purification products of smoke, fumes or exhaust gases
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 18/141 Slags
• CPC Class Codes: C04B 18/167 Recycled materials, i.e. waste materials reused in the production of the same materials
• CPC Class Codes: C04B 22/064 of the alkaline-earth metals
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

The present invention provides combustion products of hydrocarbon fuels and controlled amounts of metal oxide strength enhancing materials. The combustion products are useful as additives to cementitious materials. A hydrocarbon fuel such as coal is introduced into a combustion chamber and selected amounts of materials comprising CaO, SiO₂ and Al₂O₃ are also introduced into and/or downstream from the chamber. The hydrocarbon fuel undergoes combustion while the metal oxide strength enhancing materials react with each other and/or the ash or other reaction products of the hydrocarbon fuel. The combustion products have been found to significantly increase compressive strengths of cements such as Portland cement. A reduction in SO₂ emission levels also results from the introduction of the metal oxide strength enhancing materials into the combustion process.

Claims

1. A cementitious material comprising:

cement; and

a cement additive comprising a combustion product of hydrocarbon fuel and a strength enhancing material comprising controlled amounts of calcium oxide, silicon dioxide and aluminum oxide, wherein the cement additive increases 28-day compressive strength of the cementitious material above 28-day compressive strength of the cementitious material without the cement additive.

2. The cementitious material of claim 1, wherein the cement additive comprises relative weight ratios of the calcium oxide, silicon dioxide and aluminum oxide in amounts of from about 20 to about 80 weight percent CaO, from about 5 to about 60 weight percent SiO₂, and from about 5 to about 40 weight percent Al₂O₃.

3. The cementitious material of claim 1, wherein the cement additive comprises relative weight ratios of the calcium oxide, silicon dioxide and aluminum oxide in amounts of from about 22.5 to about 70 weight percent CaO, from about 10 to about 57.5 weight percent SiO₂, and from about 7.5 to about 30 weight percent Al₂O₃.

4. The cementitious material of claim 1, wherein the cement additive comprises relative weight ratios of the calcium oxide, silicon dioxide and aluminum oxide in amounts of from about 25 to about 65 weight percent CaO, from about 15 to about 55 weight percent SiO₂, and from about 10 to about 25 weight percent Al₂O₃.

5. The cementitious material of claim 1, wherein the strength enhancing material is combusted with the hydrocarbon fuel in an amount of at least 8 weight percent of the total combined weight of the strength enhancing material and the hydrocarbon fuel.

6. The cementitious material of claim 1, wherein the strength enhancing material is combusted with the hydrocarbon fuel in an amount of at least 10 weight percent of the total combined weight of the strength enhancing material and the hydrocarbon fuel.

7. The cementitious material of claim 1, wherein the strength enhancing material comprises at least one material selected from limestone, waste concrete such as recycled Portland cement concrete, recycled ground granulated blast furnace slag, recycled crushed glass, recycled crushed aggregate fines, silica fume, cement kiln dust, lime kiln dust, weathered clinker, clinker, aluminum slag, copper slag, granite kiln dust, zeolites, limestone quarry dust, red mud, fine ground mine tailings, oil shale fines, bottom ash, dry stored fly ash, landfilled fly ash, ponded flyash, sopodumene lithium aluminum silicate materials, and lithium-containing ores.

8. The cementitious material of claim 1, wherein the strength enhancing material comprises at least two materials selected from limestone, blast furnace slag, concrete, glass and kaolin.

9. The cementitious material of claim 1, wherein the hydrocarbon fuel comprises bituminous coal and the strength enhancing material comprises kaolin.

10. The cementitious material of claim 9, wherein the combustion product comprises metakaolin.

11. The cementitious material of claim 1, wherein the strength enhancing material comprises from about 7 to about 20 weight percent limestone based on the total combined weight of the strength enhancing material and the hydrocarbon fuel.

12. The cementitious material of claim 1, wherein the strength enhancing material comprises from about 1 to about 5 weight percent ground granulated blast furnace slag based on the total combined weight of the strength enhancing material and the hydrocarbon fuel.

13. The cementitious material of claim 1, wherein the strength enhancing material comprises from about 1 to about 5 weight percent crushed concrete based on the total combined weight of the strength enhancing material and the hydrocarbon fuel.

14. The cementitious material of claim 1, wherein the strength enhancing material comprises from about 0.1 to about 2 weight percent crushed glass based on the total combined weight of the strength enhancing material and the hydrocarbon fuel.

15. The cementitious material of claim 1, wherein the strength enhancing material comprises from about 0.1 to about 5 weight percent kaolin based on the total combined weight of the strength enhancing material and the hydrocarbon fuel.

16. The cementitious material of claim 1, wherein the strength enhancing material comprises from about 0.01 to about 1 weight percent silica fume based on the total combined weight of the strength enhancing material and the hydrocarbon fuel.

17. The cementitious material of claim 1, wherein the hydrocarbon fuel comprises bituminous coal.

18. The cementitious material of claim 1, wherein the hydrocarbon fuel comprises sub-bituminous coal.

19. The cementitious material of claim 1, wherein the combustion product has an average particle size of less than 20 microns.

20. The cementitious material of claim 1, wherein the combustion product has an average particle size of from about 1 to about 10 microns.

21. The cementitious material of claim 1, wherein the cement additive comprises greater than 25 weight percent of the cementitious material.

22. The cementitious material of claim 1, wherein the cement additive comprises from about 30 to about 95 weight percent of the cementitious material.

23. The cementitious material of claim 1, wherein the cement comprises Portland cement.

24. The cementitious material of claim 1, wherein the cement additive increases the 28-day compressive strength of the cementitious material more than 20 percent above the 28-day compressive strength of the cement without the cement additive.

25. The cementitious material of claim 1, wherein the 28-day compressive strength of the cementitious material is at least 8,000 psi.

26. The cementitious material of claim 1, wherein the 28-day compressive strength of the cementitious material is at least 9,000 psi.

27. A cement mix comprising:

cement; and

a cement additive comprising a combustion product of hydrocarbon fuel and at least 10 weight percent of a strength enhancing material comprising controlled amounts of calcium oxide, silicon dioxide and aluminum oxide, wherein the cement additive increases 28-day compressive strength of the cementitious material above 28-day compressive strength of the cementitious material without the cement additive.

28. The cement mix of claim 27, wherein the cement additive comprises greater than 25 weight percent of the cement mix.

29. The cement mix of claim 27, wherein the cement additive comprises from about 30 to about 95 weight percent of the cement mix.

30. The cement mix of claim 27, wherein the cement comprises Portland cement.

31. A cement additive comprising a combustion product of hydrocarbon fuel and at least 8 weight percent of a strength enhancing material comprising controlled amounts of calcium oxide, silicon dioxide and aluminum oxide, wherein when the cement additive is added to cement it increases 28-day compressive strength of the cement more than 20 percent.

32. A method of making a cement additive comprising combusting a hydrocarbon fuel in the presence of at least one metal oxide strength enhancing material to form a combustion product comprising controlled amounts of calcium oxide, silicon dioxide and aluminum oxide, wherein the cement additive comprises relative weight ratios of the calcium oxide, silicon dioxide and aluminum oxide in amounts of from about 20 to about 80 weight percent CaO, from about 5 to about 60 weight percent SiO₂, and from about 5 to about 40 weight percent Al₂O₃.

33. A method of modifying a hydrocarbon fuel combustion product comprising:

introducing the hydrocarbon fuel and a strength enhancing material comprising controlled amounts of calcium oxide, silicon dioxide and aluminum oxide into a combustion chamber;

heating the hydrocarbon fuel strength enhancing material in the combustion chamber to yield a combustion product; and

recovering the combustion product comprising relative weight ratios of CaO, SiO₂ and Al₂O₃ in amounts of from about 20 to about 80 weight percent CaO, from about 5 to about 60 weight percent SiO₂, and from about 5 to about 40 weight percent Al₂O₃.

34. The method of claim 33, wherein the hydrocarbon fuel and the strength enhancing material are introduced into the combustion chamber separately.

35. The method of claim 33, further comprising:

monitoring at least one property of the material in the combustion chamber; and

in response to the monitoring, automatically modifying a flow rate of the strength enhancing material.

36. The method of claim 35, wherein the monitoring comprises using a sensor positioned in flow communication with the combustion chamber.

37. The method of claim 36, wherein the sensor comprises an x-ray fluorescence spectrometer, a mass spectrometer, an atomic absorption spectrometer, a residual gas analyzer, an inductively-coupled plasma optical emission spectrometer, or a Fourier transform infrared spectrometer.

38. The method of claim 36, further comprising:

receiving from the sensor via a feedback system a value of the property;

comparing the value to a reference; and

if the value does not equal or exceed the reference, adjusting a flow rate of the strength enhancing material.

39. The method of claim 33, further comprising blending the recovered combustion product with cement to yield a modified cementitious product comprising about 25 to about 95 weight percent of the recovered combustion product, and from about 5 to about 75 weight percent of the cement.

40. A combustion system comprising:

a combustion chamber for combusting a hydrocarbon fuel and a strength enhancing material;

a source of the hydrocarbon fuel;

a source of the strength enhancing material;

at least one injector configured to deliver the hydrocarbon fuel and the strength enhancing material to the combustion chamber; and

a sensor in communication with the chamber for monitoring at least one property of a combustion product of the hydrocarbon fuel and the strength enhancing material.

41. The system of claim 40, wherein the sensor comprises an x-ray fluorescence spectrometer, a mass spectrometer, an atomic absorption spectrometer, a residual gas analyzer, an inductively-coupled plasma optical emission spectrometer, or a Fourier transform infrared spectrometer.

42. The system of claim 40, further comprising a feedback system that receives a value of the property from the sensor and transmits the value to a controller, wherein the controller is configured to transmit in response to the value a signal to the injector to adjust a flow rate of the strength enhancing material.