United States Patent Application: 0060201395
We have many times documented the fact, that, not only can Coal Ash and Flue Gas Desulfurization, FGD, wastes be utilized, actually in various ways, both in the making of Portland-type Cement, PC, and, as a reactive aggregate, in the making of Portland-type Cement Concrete, PCC, but, that the resulting Concrete is typically stronger and more resistant to chemical corrosion than conventional PCC.
A few of our previous reports demonstrating some of that can be accessed via:
West Virginia Coal Association | Pittsburgh Converts Coal Ash and Flue Gas into Cement | Research & Development; concerning: "United States Patent 5,766,339 - Producing Cement from a Flue Gas Desulfurization Waste; 1998; Assignee: Dravo Lime Company, Pittsburgh; Abstract: Cement is produced by forming a moist mixture of a flue gas desulfurization process waste product containing 80-95 percent by weight calcium sulfite hemihydrate and 5-20 percent by weight calcium sulfate hemihydrate, aluminum, iron, silica and carbon (and) wherein said source of aluminum and iron comprises fly ash"; and:
West Virginia Coal Association | Coal Ash Concrete More Durable, Resists Chemical Attack | Research & Development; concerning: "United States Patent 5,772,752 - Sulfate and Acid Resistant Concrete and Mortar; 1998; Assignee: New Jersey Institute of Technology, Newark; Abstract: The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance".
And, herein we learn that both Coal Ash and FGD wastes can be used together, not, as in the above "United States Patent 5,766,339 - Producing Cement from a Flue Gas Desulfurization Waste", for the making of the Cement, but, as in "United States Patent 5,772,752 - Sulfate and Acid Resistant Concrete and Mortar", as a blended and reactive "Pozzolan", for addition to the Cement after the Cement has been made from whatever raw materials; a reactive Pozzolan that enhances both the physical strength and the chemical resistance of the final Concrete.
Comment follows and is inserted within excerpts from the initial link in this dispatch to:
"United States Patent Application 20060201395 - Blended Fly Ash Pozzolans
(Since, as we have previously and separately noted, official United States Patent and Trademark Office links to their electronic records of US Patent Applications frequently prove unstable and unreliable, here is a link to an independent site's record of "US Patent Application 20060201395" which enables downloading of the document file itself: Blended fly ash pozzolans - Barger, Gregory S. .)
Date: September, 2006
Inventors: Gregory Barger and Charles Widenhoft, Overland Park, Kansas
(As we've many times noted, the eventual Assignee of rights to US Patents, if different from the inventors themselves, is often not named in earlier publications of US Patent Applications.
As can be learned via:
Gregory S. Barger Presented Award of Merit; "Gregory S. Barger, technical center director at Ash Grove Cement Co., Overland Park, Kan., has received the ASTM International Award of Merit and its accompanying title of fellow. The Award of Merit is the highest society award granted to an individual ASTM member for distinguished service and outstanding participation in committee activities. Barger received the Award of Merit from ASTM International Committees C01 on Cement and C09 on Concrete and Concrete Aggregates for his exceptional leadership and technical contributions related to standards on compositional analysis, use and testing of hydraulic cements and hydraulic cement concretes"; and, sadly, via:
Charles T. Wiedenhoft, July 27, 2010 | Sandusky Register; "Charles T. Wiedenhoft, 60, of Olathe, Kan., died unexpectedly Tuesday, July 27, 2010. He was President and CEO of Ashgrove Cement Company in Overland Park, Kansas";
the likely Assignee of rights, if and when a United States Patent issues from our subject, "United States Patent Application 20060201395", will be "Ashgrove Cement Company". And, as can be learned via:
Ash Grove - Strong Foundations. Strong Future. "Ash Grove Cement Company was the first U.S.-based cement company to join the World Business Council for Sustainable Development as an active participant in its Cement Sustainability Initiative"; and:
Ash Grove Cement Company - Wikipedia, the free encyclopedia; "Ash Grove Cement Company is ... the sixth largest cement manufacturer in North America, and the largest US-owned cement company. The company was established in 1882 ... as the Ash Grove White Lime Association. It commenced cement manufacture in 1908 (and) now has an annual cement manufacturing capacity of nearly 9 million tons, from 9 plants: The company makes Portland cements, flyash cements, masonry cements, oilwell cements and soil stabilizers. It also operates a lime plant in Oregon, many ready-mix concrete plants in the Midwest, and a limestone quarry (in) British Columbia";
Ash Grove Cement ain't just a one-truck concrete mix plant down by the river. They are big enough, and have the resources, to not only know what they're doing, but to figure out better ways of doing it.)
Abstract: Novel premium blended pozzolans for use with hydraulic cement are created by intergrinding an ASTM Class F or Class C coal fly ash and a source of calcium sulfate, such as gypsum, so that the resultant mixture has a fineness of at least 90% passing through a 45 micron sieve. The novel mixture meets the requirements of ASTM C 618. Alternately, a novel concrete composition can be formed using the blended pozzolan with a hydraulic cement, aggregate and water so as to produce a concrete having improved strength, ASR mitigation, improved sulfate resistance and lowered permeability. The novel pozzolans not only reduce production costs by decreasing fuel and raw material consumption per ton of cement, but they also use by-product waste materials from another industry to create a premium product for the construction industry.
(First of all, "Class F or Class C coal fly ash" means that, generally speaking, Coal Ash from burning either or both our eastern Bituminous Coal and our western Lignite Coal can be utilized in this process. And, as seen, for one example, in:
Pittsburgh Makes Coal Flue Gas Gypsum for Fly Ash Cement | Research & Development; concerning: "United States Patent 5,312,609 - Sulfur Dioxide Removal from Gaseous Streams with Gypsum Product Formation; 1994; Assignee: Dravo Lime Company, Pittsburgh; Abstract: A method is provided for removing sulfur dioxide from a hot gaseous stream while directly producing .alpha.-hemihydrate gypsum from a scrubber effluent. A method of removing sulfur dioxide from a sulfur dioxide-containing hot gaseous stream and producing .alpha.-hemidydrate gypsum";
the "gypsum" can, indeed, be made from Coal power plant flue gas desulfurization wastes. Further, concerning "ASTM C 618", see:
ASTM C618 - 12 Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete; "ASTM (American Society for Testing and Materials) C618 - 12 Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete; This specification covers coal fly ash and raw or calcined natural pozzolan for use in concrete where cementitious or pozzolanic action, or both, is desired, or where other properties normally attributed to fly ash or pozzolans may be desired, or where both objectives are to be achieved. Fly ash and natural pozzolans shall conform to the prescribed chemical composition requirements and physical requirements. The materials shall be tested for fineness, strength activity index, water requirement, soundness, and autoclave expansion or contraction".)
Claims: A blended pozzolan for use with hydraulic cement and comprising:
a) fly ash meeting the requirements of ASTM C 618 Class C or F;
b) a calcium sulfate component; and:
c) the fly ash and the calcium sulfate component being interground to a fineness of at least 90% passing through a 45 micron sieve and meeting the requirements of ASTM C 618 for coal fly ash.
The blended pozzolan ... wherein the calcium sulfate component is gypsum.
The blended pozzolan ... wherein there is an approximate proportion of 93% fly ash and 7% calcium sulfate component.
(Now, in Coal-fired power plants equipped with Flue Gas Desulfurization scrubbers, as in the above-cited "United States Patent 5,312,609 - Sulfur Dioxide Removal from Gaseous Streams with Gypsum Product Formation", we don't, here, really know how much "calcium sulfate" synthetic Gypsum would be produced, relative to the amount of "coal fly ash"; but, our guess is, that, depending of course upon the Coal itself, a 7% to 93% ratio might not be too far from the natural mark.)
The blended pozzolan ... wherein the proportion of fly ash to calcium sulfate component is selected to optimize sulfate resistance, volume stability, alkali silica reaction mitigation and compressive strength.
A concrete composition ... having the uniquely improved strength, alkali-silica-reactivity mitigation, improved sulfate resistance and lowered permeability.
The concrete composition ... wherein the blended fly ash is a Class F fly ash (and) wherein the calcium sulfate component is gypsum.
(Again, "Class F fly ash" is what we get from the combustion of our eastern US bituminous Coal.)
Background and Field: This invention is related to novel pozzolans for use in mixing with hydraulic cement to make concrete. Concretes prepared from the improved pozzolans of this invention exhibit unprecedented and unexpected characteristics of improved strength, ASR mitigation, improved sulfate resistance and lowered permeability. Cementitious systems of this invention are substituted in place of ordinary Portland cements ... .
In the United States, cements are divided into the following categories: (1) Portland cement; (2) Natural cement; (3) High alumina cement; (4) Supersulfate cement; and (5) Special cements. This invention is generally related to an improved blended pozzolans for use in blended or masonry cements as a premium additive to ordinary Portland cement.
(The inventors go on to provide some substantial background information on Cement and Concrete, including some good definitions and explanations of many of the terms we see in our reports concerning the making of high-performance Cement and Concrete out of Coal Ash. It's all too involved for the purposes of our report herein, but, well worth the reading for anyone genuinely interested in these sorts of potentials for our solid Coal Combustion Products.)
Summary: A novel and premium grade pozzolan is disclosed which is superior for use with hydraulic cement. The pozzolan is a fly ash, preferably a Class F fly ash but possibly a Class C fly ash, meeting the requirements or ASTM C 618. The fly ash and a calcium sulfate component, such as gypsum or anhydrite or minerals on the continuum between gypsum and anhydrite, are interground in a grinding mill so that the mixture is finely ground to a fineness of at least 90% passing through a 45 micron sieve. The finely interground mixture fully meets the requirements of ASTM C618 for coal fly ash to be used as an additive with hydraulic cement.
The blended pozzolan is a premium product and can be added to cement by a ready-mix plant operator to create a concrete having superior properties of compressive strength, ASR mitigation, improved sulfate resistance and lowered permeability when compared to typical Portland Cement concretes.
Fly ash meeting the requirements of ASTM 618 Class F or Class C are specified and preferably Class F for use in the invention."
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It's tough to summarize it any more succinctly than the employees of this large, actually international, maker of Portland Cement and Concrete do, but, in sum:
We can make "a concrete having superior properties of compressive strength, ASR mitigation, improved sulfate resistance and lowered permeability" by using and consuming, "preferably" our eastern bituminous Coal "Class F" Fly Ash and a "calcium sulfate component", "gypsum", which we can, via the process of the above-cited "United States Patent 5,312,609 - Sulfur Dioxide Removal from Gaseous Streams with Gypsum Product Formation", make from a Coal-fired power plant flue gas desulfurization waste product; and, in so doing, "reduce production costs by decreasing fuel and raw material consumption per ton of cement" made.
And - - without going again into the details, since we've discussed it in many previous reports, such as:
West Virginia Coal Association | Scientists Convert Coal Ash to Cement | Research & Development; which concerns, among other things, the report: "Role of Fly Ash In Reducing Greenhouse Gas Emissions During The Manufacturing Of Portland Cement; V.M. Malhotra, Scientist Emeritus, Advanced Concrete Program, CANMET, Natural Resources Canada; Synopsis: This paper gives a global review of portland cement production and greenhouse gas emissions during its manufacturing. It is emphasized in the paper that fly ash is and will remain the major supplementary cementing materials for decades to come, and the concrete industry must concentrate its major efforts for the increased use of fly ash in concrete. Not only is the manufacturing of portland cement highly energy intensive, it also is a significant contributor of the greenhouse gases. The production of one tonne of cement contributes about 1 tonne of CO2 to the atmosphere. (And, about) half of the CO2 emissions are due to the calcination of limestone";
and, will be treating it again more fully in some reports to follow - - each ton of conventional Portland-type Cement we can "displace" by using, as herein, a blend of Coal Fly Ash and the product of Flue Gas Desulfurization to replace some of the conventional raw materials in the making of, remember, a "premium" Cement or Concrete, will equate to about one ton of CO2 not emitted to the atmosphere by the conventional Cement-making process.
It all sounds extremely win-win, environmentally and economically, to us, here.
But, since none of it is being fully and enthusiastically reported on by the Coal Country press, are we to draw the conclusion that our honorable ink-stained wretches are actually more interested in lose-lose situations, maybe because they make more catchy headlines?
Well, you know, if thousands of Coal miners lose their jobs because of all the regulations coming down the pike - - regulations concerning things like CO2 and Coal Ash - - and those laid-off Coal miners can't then buy the cars being sold by all those dealers paying the press all that money for all those full-page ads in the Sunday paper, there might wind up being not many newspapers left to print the headlines on, in any case.
But, that's okay, we guess. At least all of those unemployed journalists can start meeting some new people and making some new friends in the Coal mining community, while they're all standing together in the unemployment line.
