In an earlier dispatch, now accessible on the West Virginia Coal Association's web site via the link:
Wyoming Converts Coal Ash to Construction Aggregates | Research & Development; concerning:
"United States Patent 6,334,895 - Producing Manufactured Materials from Coal Combustion Ash; 2002; Inventor: Alan Bland, Wyoming; Assignee: The University of Wyoming Research Corporation; Abstract: This invention discloses a system for cold bond processing of combustion ash which enhances various characteristics of the resulting cured consolidated combustion ash materials. Specifically, the invention relates to processing techniques which enhances both density and strength of the of the consolidated combustion ash materials. The invention also relates to processing techniques which control various chemical reactions which assure that certain types of minerals are formed in the proper amounts which results in a cured consolidated combustion ash material which has greater dimensional stability and enhanced resistance to degradation. Embodiments for both normal weight and light weight combustion ash aggregates are disclosed which meet various ASTM and AASHTO specifications";
we documented that the University of Wyoming had developed an economical process for converting some solid Coal Utilization Byproducts into a variety of versatile aggregates, replacements for crushed stone and other materials, that met the applicable standards for use in road, and other, construction.
In another report:
Wyoming Markets Coal Ash-based Construction Aggregate | Research & Development; centered on:
"United States Patent 6,517,631 - Producing a Coal Combustion Ash Composition; 2003; Inventor: Alan Bland, Wyoming; Abstract: This invention discloses a system for cold bond processing of combustion ash which enhances various characteristics of the resulting cured consolidated combustion ash materials. Specifically, the invention relates to processing techniques which enhances both density and strength of the of the consolidated combustion ash materials. The invention also relates to processing techniques which control various chemical reactions which assure that certain types of minerals are formed in the proper amounts which results in a cured consolidated combustion ash material which has greater dimensional stability and enhanced resistance to degradation. Embodiments for both normal weight and light weight combustion ash aggregates are disclosed which meet various ASTM and AASHTO specifications";
we learned that the University of Wyoming and their partners, the Western Research Institute, had not only improved their technology for making perfectly-qualified concrete and construction aggregates out of Coal Ash, but had begun to market those aggregates, under the trade name "Synag"(R).
Herein, we see that they continued to refine and improve their technology for the "cold bond processing" of Coal Ash, with the result being not only the capability to manufacture a greater range of both lightweight and standard construction aggregates from Coal Ash, which Coal Ash aggregates exhibit even better physical properties, relative to the established standards for construction aggregates; but, also, the ability to use a certain amount of industrially-polluted water in the manufacture of the aggregates and, thus, "sequester" the pollutants that were in the water in those higher-performance solid aggregates. .
Comment follows, and is inserted within, excerpts from the initial link in this dispatch to:
"United States Patent 6,808,562 - Stable Consolidated Combustion Ash Material
Date: October, 2004
Inventor: Alan Bland, WY
Assignee: The University of Wyoming Research Corporation, Laramie
Abstract: This invention discloses a system for cold bond processing of combustion ash which enhances various characteristics of the resulting cured consolidated combustion ash materials. Specifically, the invention relates to processing techniques which enhances both density and strength of the of the consolidated combustion ash materials. The invention also relates to processing techniques which control various chemical reactions which assure that certain types of minerals are formed in the proper amounts which results in a cured consolidated combustion ash material which has greater dimensional stability and enhanced resistance to degradation. Embodiments for both normal weight and light weight combustion ash aggregates are disclosed which meet various ASTM and AASHTO specifications.
Claims: A method of generating a combustion ash composition comprising the steps of: providing combustion ash having an amount of hydratable oxide; assessing said amount of hydratable oxide in said combustion ash; assessing a first amount of water to convert said amount of hydratable oxide to about five weight percent; combining at least said first amount of water with said combustion ash to generate a partially hydrated combustion ash; converting said amount of hydratable oxide to about five weight percent; expanding said partially hydrated combustion ash to a first molar expansion volume; allowing said partially hydrated combustion ash to heat as a result of exothermic hydration of said hydratable oxides; permitting evaporation or a portion of said first amount of water from said partially hydrated combustion ash; assessing a second amount of water to convert substantially all of the remaining hydratable oxide to hydroxide; and adding at least said second amount of water to said partially hydrated combustion ash to generate a combined material.
(It seems a little confusing, at first. We had to sort of draw it out, graph it, to get an understanding of the steps involved. And, don't be put off by the need for a certain amount of "hydratable oxide". If the Coal Ash itself doesn't have enough of it, we can certainly add some standard and common Portland-type cement, a blend mostly of CaO and MgO, depending on the grade and type of limestone used in its manufacture; both of which are most definitely suitable "hydratable oxide"s.)
A method of generating a combustion ash composition ... further comprising the step of compacting said combined material and allowing said compacted combined material to cure to form a stable compacted cured material.
A method of generating a combustion ash composition ... wherein said step of combining at least said first amount of water with said combustion ash, and said step of adding at least said second amount of water to said partially hydrated combustion ash comprises utilizing a water weight of about 10% to about 60% of said combustion ash.
(You add water to it, just like you do when you're mixing cement. It ain't rocket science.)
A method of generating a combustion ash composition ... further comprising the step of reducing average pore volume of said stable compacted cured material.
(You tamp it down, or otherwise compress it; again, standard practice.)
A method of generating a combustion ash composition ... wherein said stop of reducing an average pore volume of said stable compacted cured material comprises the step of establishing said average pore volume of said stable compacted cured material to between about 15% to about 40%.
(You can, in other words, vary the density; so as to make, as desired, either standard or lightweight aggregate, for use in different applications.)
A method of generating a combustion ash composition ... further comprising the step of adding an amount of pore filling controlling compound to said combustion ash insufficient to fill a pore volume of said stable compacted cured material.
A method of generating a combustion ash composition ... further comprising the step of generating an amount of non-pore filling compound by reacting an amount of precursor pore filling compound in said combustion ash with said amount of said pore filling controlling compound.
(It can, in other words, and as becomes clear in the full Disclosure, be "foamed" a little, to reduce the weight and density, just like some types of plastic.)
A method of generating a combustion ash composition ... further comprising the step of adding an amount of strength additive to said partially hydrated combustion ash.
A method of generating a combustion ash composition ... wherein (the) combustion ash (is) selected from the group consisting of fluidized bed combustion ash, pressurized fluidized bed combustion ash, off specification Class C ash, off specification Class F ash, spray drier ash, sorbent injection ashes, incinerator ash, and flue gas desulfurization ash.
(The specification of "off specification" Ash means that you can use Ash that might not be suitable for other purposes; and, there are other uses for Coal Ash, such as just a simple, straightforward aggregate or filler, to replace some of the sand, for concrete. Further, as in the specification of "flue gas desulfurization ash", we remind you of our earlier reports:
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"; and, describing a process very similar to that of our subject:
Consol Converts Coal Ash to Concrete Aggregate | Research & Development; concerning:
"United States Patent 5,364,572 - Process for Making High-Strength Synthetic Aggregates; 1994; Assignee: Consolidation Coal Company, Pittsburgh; Abstract: A process for making high-strength aggregates including hydrating calcium oxide containing coal combustion ash for a sufficient period of time to convert a high percentage of the calcium oxide to calcium hydroxide prior to forming the aggregates and curing the aggregates in high humidity. The moisture of the hydrated material is monitored to vary the hydration moisture to the desired set point. Further, the process involves producing high-strength aggregates from calcium hydroxide containing FGD ashes such as generated from duct sorbent injection and spray dryer processes";
wherein it's confirmed that the "flue gas desulfurization ash" of our subject, the "FGD ashes" as Consol puts it just above, can contribute valuable components to a Fly Ash consolidation process.)
A method of generating a combustion ash composition ... wherein said step of providing a pore filling controlling compound comprises providing a pore filling controlling compound selected from the group consisting of carbon dioxide gas, soluble carbonates, carbonic acid, sodium carbonate, potassium carbonate, magnesium hydroxide, and trona.
(Note the above potential for productively "sequestering" at least some CO2 in a concrete aggregate.)
A method of making a material from combustion ash ... wherein said precursor pore filling compound is selected from the group consisting of calcium oxide, ..., magnesium oxide, soluble sulfates, soluble alumina, soluble silicates, calcium silicate, calcium aluminate, hydrated lime, and calcium sulfo-aluminate.
(Again, basically nothing but a little Portland-type cement, "calcium oxide, ..., magnesium oxide", is needed to, if more weight and strength is desired, fill the pores in the Fly Ash aggregate.)
A method of generating a combustion ash composition ... wherein said step of adding said strength additive to said partially hydrated combustion ash comprises the step of adding a strength additive selected from the group consisting of Portland Cement, Class C ash ... and self cementing ash.
A method of generating a combustion ash composition ... further comprising the step of selecting said first amount of water and said second amount of water from the group consisting of coal pile runoff, cooling tower blow down, paper mill effluent, industrial waste waters, and seawater.
(Thus, as noted in our introduction, the potential for utilizing, and "sequestering", industrial wastes.)
A method of generating a combustion ash composition ... further comprising the step of establishing a combustion ash composition to meet specifications selected from the group consisting of normal weight aggregate for road base, concrete aggregate, structural fill, liners, ASTM 698, ASTM 1557, ASTM C-88 soundness index, and ASTM LA abrasion.
(A broader range of standards, thus, can be met by this variable-density aggregate.)
A method of generating a combustion ash composition ... wherein said steps of compacting said combined material and allowing said compacted combined material to cure to form a stable compacted cured material comprises the stop of selecting a compaction method from the group consisting of pelletization, briquetting, and agglomeration.
A method of generating a combustion ash composition as described in claim 1 further comprising the step of adding a precursor pore filling compound and a strength additive to said partially hydrated combustion ash.
A method of generating a combustion ash composition ... further comprising compacting said combined material with a reduced compactive effort.
A method of making a material from combustion ash ... further comprising the step of allowing said compacted combustion ash to cure to form a stable compacted cured material.
A method of making a material from combustion ash ... wherein said step of compacting said ash and water mixture comprises the step of compacting said ash and water mixture by roller compaction.
(There are, it seems, a lot if things you can do, and lot of things you can make, with this stuff.)
A method of making a material from combustion ash ... wherein said step of selecting a combustion ash comprises the step of selecting a combustion ash from the group consisting of fluidized bed combustion ash, pressurized fluidized bed combustion ash, Class C ash, off specification Class C ash, Class F ash, off specification Class F ash, spray drier ash, sorbent injection ashes, incinerator ash, and flue gas desulfurization ash.
(Basically, any and all Coal Utilization Byproducts can be productively consumed by this process.)
A cured combustion ash composition ... further comprising an unconfined compressive strength of said cured composition selected from the group consisting of greater than 700 pounds per square inch; greater than 1000 pounds per square inch; greater than 1300 pounds per square inch; greater than 1600 pounds per square inch; greater than 2000 pounds per square inch; and greater than 3000 pounds per square inch.
(We can, in addition to lightweight aggregate, make some very strong aggregates from Coal Ash.)
Background and Field: The invention relates to a system for the treatment of ashes or residues from the combustion of carbonaceous fuels, such as coal. The invention discloses both methods and apparatus to control various physical and chemical characteristics of combustion ash as they relate to cold bonding processes, and as they relate to the cured consolidated materials which result from these processes. Specifically, this invention relates to cured consolidated combustion ash materials which have been standardized for use as normal weight and light weight aggregate for use in structural and landfill applications.
The combustion of carbonaceous fuels for the production of electricity or process steam by the utility and industrial sectors is a major generator of combustion ash. Combustion technologies such as fluidized bed combustion (FBC) and pressurized fluid bed combustion (PFBC) are widely implemented. Apprehension about pollution from the smoke stack industries and utilities has led to the implementation of clean coal technologies that addresses flue gas contaminants, not only for particulate, but also gaseous emission, such as sulfur oxides. These flue gas desulfurization (FGD) technologies are widespread and cover a range of techniques including wet scrubbers or wet FGD; dry scrubber FGD (i.e., spray driers); sorbent injection technologies; and fluidized bed combustion (FBC) technologies each of which produce a particular type of ash as a by-product.
The development of re-use technologies for each of these ashes, as well as those that result from the combustion of carbonaceous fuels without FGD technologies, has been slow. The obstacles are both technical, as well as regulatory and legislative. One of the prominent technical issues is the inability to produce ash-based products which have certain required engineering properties or meet particular standards in the industry.
Summary: Accordingly, it is the broad object of the present invention to provide a system for the production of cured consolidated combustion ash materials from cold bonding processes having novel or enhanced characteristics. One specific goal in this respect is to provide both methods and apparatus for a combustion ash cold bonding process to produce standardized normal weight aggregate for use in road base; for use in concrete having structural, masonry and insulation applications, and for use in light weight aggregate applications."
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There is, actually, quite a lot more to the full Disclosure, which defines the process variations in much greater detail, specifies the Coal Ash products thus manufactured; and, identifies the various standards they must meet and the markets they could serve.
The upshot is, though, that every last danged bit of solid "stuff" that might come out of the back end of a Coal-fired boiler can be scraped together and productively utilized in a variety of applications, the needs of which applications might otherwise require the extraction and consumption of other, natural, resources.
Thus, the process of "United States Patent 6,808,562 - Stable Consolidated Combustion Ash Material", and it's related technologies, a few of which we cited above, should be of some interest, we imagine, to the authors and supporters of bills such as:
Bill Summary & Status - 112th Congress (2011 - 2012) - H.R.1391 - CRS Summary - THOMAS (Library of Congress), "H.R. 1391; RCCRA Act of 2011; Sponsor: Rep. David B. McKinley, WV-1; Recycling Coal Combustion Residuals Accessibility Act of 2011 or the RCCRA Act of 2011 - Amends the Solid Waste Disposal Act to exempt fly ash waste, bottom ash waste, slag waste, and flue gas emission control waste generated primarily from the combustion of coal or other fossil fuels from regulation as hazardous waste under such Act".
And, they might be of some interest to West Virginia's Congressman McKinley's, and his co-sponsors', many thousands of United States Coal Country constituents.
Far past time they all had a chance to learn publicly about the true, genuine potentials for such full, complete "Recycling" of "Coal Combustion Residuals", as represented herein by the process of our subject, "United States Patent 6,808,562 - Stable Consolidated Combustion Ash Material", don't you think?