United States Patent Application: 0120156381
In the very recently-published United States Patent Application centered on the productive use of Coal Ash we bring to your attention herein, we introduce a technical concept that has come up with some consistency in the course of our research into the consumption and utilization of Coal Ash in the synthesis of Cement, or materials that are in many ways like Cement.
And, keep in mind that when we use the label "Cement", it means quite a lot more than just Portland-type Cement, "PC", and Portland-type Cement Concrete, "PCC".
There exists a spectrum of, essentially, mineral-based compositions - i.e., plasters, grouts, mortars - that are, like PC and PCC, essentially fluids of a usually high viscosity when initially blended, but which, through typically a combination of both physical and chemical processes, "cure", or harden up, to form a solid and mineral-like product.
Those types of compounds typically differ from solid, what we might think of as non-mineral, "organic" compounds, like plastics and wood, both of which, even though one is synthetic and the other natural, are considered to be "polymers", and which have the properties they do because they incorporate the element Carbon into their molecular structure, because those mineral-based compositions don't center on Carbon as their key and central element.
Because of the unique way Carbon, out of all the elements, is able to chemically interact both with itself and with other elements, it allows large and complex molecules to be formed that are both stable and strong, and which can impart characteristics of flexibility, resilience and impermeability to the things which are composed of such molecules.
Your skin, a vinyl beach ball and latex paint are all suitable examples.
The complexities of how all of that is made possible by the way the Carbon atom is constructed, despite the best efforts at explanation and instruction made by two of our fully-functioning advisors, is beyond our now sadly limited comprehension.
However, another element closely related to Carbon in the general way the atoms of it are built is Silicon.
And, even though we might most often think of Silicon in terms of beach sand and computer "chips", it, too, can be combined, though not quite as easily as Carbon, in large, complex molecules with properties similar in many respects to some of those made in the same way out of Carbon.
For a little background, see:
Silicone - Wikipedia, the free encyclopedia; "Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications ..., , cookware, and insulation. Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements. Some common forms include silicone oil, silicone grease, silicone rubber, and silicone resin"; and:
Silicone rubber - Wikipedia, the free encyclopedia; "Silicone rubber is an elastomer (rubber-like material) composed of silcone - itself a polymer - containing silicon together with carbon, hydrogen, and oxygen".
Silicon-based polymers aren't, again and unfortunately, as easy to make as Carbon-based polymers; but, they do have, in some cases, better properties. They can, for instance, be stronger, tougher and not nearly as flammable.
And, they do have one tremendous advantage:
Unlike many, even most, Carbon-based polymers, we don't need petroleum to make them.
And, as we will document and explain in coming reports, there is a fledgling industry, starting actually to blossom in Europe, based on the development and use of Silicon-based polymers, which are starting to be called, since they are based, in essence, on mineral and earth-based, rather than on organic, raw materials, "Geopolymers".
Even better, we have a store of Silicon raw ore already in finely-divided form ideal for processing, with more being made every day:
Coal-fired power plant Fly Ash.
Now, one property of polymers, sometimes also known as "elastomers", although the two labels aren't exactly synonymous, that everyone sort of instinctively realizes, is that they are, typically, more resistant to corrosion, i.e., rust, acid attack, etc., than a lot of other things, like metal and cement.
The fact that Silicon-based polymers, specifically Fly Ash Silicon-based polymers, are more resistant to chemical corrosion, given that Cement can, in one sense, itself be construed as a polymer, is documented in our report of:
West Virginia Coal Association | Coal Ash Concrete More Durable, Resists Chemical Attack | Research & Development; concerning: "US Patent 5,772,752 - Sulfate and Acid Resistant Concrete and Mortar; 1998; Assignee: New Jersey Institute of Technology; 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 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".
But, we have a vast infrastructure already made out of traditional Portland-type Cement and Concrete, which materials are, in some types of harsh environments, very susceptible to corrosion.
And one way to impart to the components of that PC and PCC infrastructure the corrosion-resistant properties of Coal Ash is to, rather logically, coat them with Coal Ash; or, more specifically, with, as above, a "geopolymer" made out of Coal Ash.
As explained more fully in our excerpts from the initial link in this dispatch to the recent:
"United States Patent Application 20120156381 - Geopolymer Mortar and Method
(Geopolymer Mortar and Method - Allouche, Erez)
Date: June 21, 2012
Inventors: Erez Allouche and Carlos Montes, Louisiana
(As we've previously noted for you, the affiliations of inventors, and/or the ultimate Assignee of patent rights, are most often not named or identified in early published versions of United States patent applications. But, as can be learned via:
Louisiana Tech Faculty: Allouche, Dr. Erez; and, Geopolymer Laboratory - Links;
Dr. Erez Allouche is an Associate Professor in the Department of Civil Engineering at Louisiana Tech University, whose specific area of specialization is stated to be "Advanced Cementitious Materials". Carlos Montes is, or was, a PhD. candidate working in Louisiana Tech's Geopolymer Laboratory with Professor Allouche. The ultimate Assignee of Rights, if and when a United States Patent issues from this application, is, thus, likely to be Louisiana Tech University.)
Abstract: A geopolymer mortar formed by mixing about 35% to about 45% by weight pozzolanic material, about 35% to about 45% by weight silicon oxide source, about 15% to about 20% by weight alkaline activator solution, and about 0.3% to about 2.5% by weight copper ion source. The pozzolanic material may be fly ash and the silicon oxide source may be sand. The alkaline activator solution may be a sodium hydroxide solution containing sodium silicate. The geopolymer mortar may have a viscosity in the range of about 25,000 to about 50,000 centipoise. The geopolymer mortar may be formed by further mixing one or more additives, such as surfactants, thermal spheres, anti-sagging agents, adhesion primers, or fibers. The geopolymer mortar may be applied as a protective coating on a surface of a structure.
(Not further explained in the full Disclosure is the potential for adding "thermal spheres", as above, to the Fly Ash mortar. But, there is little doubt by that they mean insulating "cenospheres", as described in:
Cenosphere - Wikipedia, the free encyclopedia; "A cenosphere is a lightweight, inert, hollow sphere filled with inert air or gas, typically produced as a byproduct of coal combustion at thermal power plants"; and:
West Virginia Coal Association | Wisconsin Recovers "Cenospheres" from Coal Fly Ash | Research & Development; concerning: "United States Patent 8,074,804 - Separation of Cenospheres from Fly Ash; 2011; Assignee: Wisconsin Electric Power Company, Milwaukee; Abstract: Methods for increasing the amount of cenospheres in a fly ash sample are disclosed. The cenospheres are obtained in a dry state by using air as the "fluid" media for separation. In one version, the invention is a two step process, that is, screen by size followed by density separation such as in a fluidizing vertical column by density. In another version of the invention, the separation by density is followed by screening by size. Additional cycles can improve purity as defined by concentration of cenospheres".
And, thus, even more Coal Combustion Byproducts can be productively utilized by adding them to a mortar which is itself made in large part of Coal Combustion Byproducts. - JtM)
Claims: A composition of matter formed by the mixing of the components comprising:
(a) about 35% to about 45% by weight fly ash;
(b) about 35% to about 45% by weight sand;
(Needless to say, there will be more Silicon in the "sand".)
(c) about 15% to about 20% by weight alkaline activator solution; and:
(d) about 0.3% to about 2.5% by weight copper ion source.
The composition of matter ... wherein the fly ash is predominantly class C or class F fly ash.
The composition of matter ... wherein the activator solution comprises a (Sodium Hydroxide) solution (as specified) including sodium silicate (in a specified ratio).
The composition of matter according ... wherein the viscosity of the composition is about 25,000 to about 50,000 centipoise (cP).
(The stuff is pretty thick; and, if any old Coal mine brattice men are reading this, it's probably about the same as the brattice wall plaster you trowel onto dry-laid block ventilation stoppings; although, keep in mind that application is not the use for which this composition is intended; although it might not be a bad one.)
The composition of matter ... wherein the copper ion source is at least one of (Copper Sulfate, Copper Oxide, or various Copper Nitrates, Copper Carbonates and Copper Hydroxides - all inexpensive and readily available stuff.)
The composition of matter ... further comprising about 0.1% to about 0.2% by weight surfactant (which) comprises a vinsol resin surfactant.
A method for protecting a surface of a structure, the method comprising the step of applying to the surface a geopolymer coating comprising a composition formed by mixing components comprising:
(a) about 35% to about 45% by weight pozzolanic material;
(b) about 35% to about 45% by weight silicon oxide source;
(c) about 15% to about 20% by weight alkaline activator solution; and:
(d) about 0.3% to about 2.5% by weight copper ion source.
The method ... wherein the pozzolanic material comprises fly ash (and) the silicon oxide source comprises sand, and ... wherein the activator solution comprises a (Sodium Hydroxide) solution (as specified) including sodium silicate (in a ratio as specified).
(Sodium Silicate, aka "water glass", and Sodium Hydroxide, aka "lye", are cheap and available. )
The method ... wherein the geopolymer coating has a viscosity (as specified) and wherein said step of applying the geopolymer coating comprises the step of spraying the geopolymer coating onto the surface.
(The stuff is thick, but can be spray applied. They weren't that common; but, if any old Coal miners out there were ever around a "Mandoseal", or gunnite, machine that sprayed a Cement and vermiculite, or Cement and fiber, mixture onto the ribs and top to protect them from air slacking, that's the general idea here.)
The method ... wherein the geopolymer coating is formed by further mixing about 0.1% to about 0.2% by weight surfactant and about 0.004% to about 0.4% by weight fibers with the other components.
A method of forming a geopolymer paste material comprising the steps of:
(a) providing an activator solution comprising a ... NaOH (Sodium Hydroxide - Lye) solution including sodium silicate (Water Glass) ... wherein the activator solution forms about 15% to about 20% by weight of the geopolymer paste material;
(b) mixing an aggregate with the activator solution, wherein the aggregate forms about 35% to about 45% by weight of the geopolymer paste material;
(c) mixing fly ash with the activator solution, wherein the fly ash forms about 35% to about 45% by weight of the geopolymer paste material;
(d) continuing mixing, with the optional step of adding water or fly ash, until obtaining a substantially homogeneous paste with a viscosity of about 25,000 to about 50,000 centipoise (cP); and:
(e) mixing an anti-sagging agent with the substantially homogeneous paste.
The method ... further comprising the step of spraying the geopolymer paste material onto a structure exposed to waste water flow ... .
The method ... further comprising the step of steam curing the geopolymer paste material on the structure.
(The requirement for "steam curing" is, admittedly, a bit of a drawback.)
Description and Background: Corrosion and deterioration of concrete pipes, manholes, wet wells, chambers, tunnels, diversion boxes, pump stations, drop structure reservoirs and treatment basins due to sulfuric acid attack is a major concern associated with wastewater conveyance and treatment facilities. Traditional cementitious materials such as Portland cement are inexpensive, but do not offer longevity under wastewater conveyance and treatment conditions. Concrete pipes are chemically attacked when subjected to acids with pH values of 6.5 or lower for extended periods of time. The pH in sewer lines can reach values of 2 or 3, and in some extreme cases 0.5. The highly acidic environment in sewer pipe lines and wastewater treatment facilities significantly reduces the life of these buried structures, causing significant financial losses.
Efforts have been made to address issues with concrete and brick surfaces in wastewater collection and treatment systems such as susceptibility to corrosion, cracking, and lack of long-term durability in harsh environments. For example, additives have been added to Portland cement in an effort to enhance the corrosion resistance of the Portland cement. Attempted additives include silica fume, fly ash, and blast furnace slag. These additives react with Ca(OH)2 present in cement paste to produce C--S--H, which enhances the resistance of the hardened cement paste in environments with pH values above 4.5.
Another example of an attempted method of protecting concrete surfaces is the addition of a thin layer of chemically resistant material (e.g., polyurethane, polyurea, epoxy, mortar epoxy, high alumina cement, or asphalt) on the inner surface of concrete pipes or other concrete surfaces. Difficulties with the addition of these thin layers include issues with ensuring adequate bonds between a spray-on coating and the host concrete surface, formation of pinholes that allow sulfuric acid and/or bacteria to penetrate the coating and destroy the bond between the coating and the host concrete surface, ensuring proper coverage at joints of concrete pipes, and construction related damage to the coating during installation. Also, both of these efforts significantly increased costs of construction and operation.
Geopolymers are inorganic alumino-silicate amorphous polymers formed by chemical reactions under highly alkaline conditions between an active pozzolanic material, such as fly ash or metakaolin, and an activator solution (e.g., a mixture of sodium hydroxide and an alkaline silicate such as sodium silicate or potassium silicate).
Polymeric chains form when a pozzolanic material comes in contact with an alkaline activator solution.
Geopolymers exhibit excellent compressive resistance (up to 120 MPa) and rapid strength gain, with 95% of their ultimate strength achieved in as little as three days under proper curing conditions. Geopolymers also exhibit low vulnerability to chemical attacks, and are practically inert to attack by sulfate salts because they are not based on calcium silicate. Because they are composed of an alkaline silicate net, geopolymers are also inert to alkali-aggregate reaction, which is a common concern with Portland cement.
Summary: A geopolymer mortar formed by mixing about 34% to about 46% by weight pozzolanic material, about 34% to about 46% by weight silicon oxide source, and about 15% to about 20% by weight alkaline activator solution, and about 0.3% to about 2.5% by weight copper ion source. The pozzolanic material may be fly ash or metakaolin. The silicon oxide source may be sand. The alkaline activator solution may be composed of a liquid sodium silicate and a sodium hydroxide solution. The geopolymer mortar may be applied to concrete or brick surfaces, and may serve as a corrosion resistant barrier.
(The above "metakaolin" is mentioned once or twice as something that can be used in addition to Fly Ash.
As can be learned via:
Metakaolin - Wikipedia, the free encyclopedia; it's form of the clay mineral, "kaolin" or "kaolinite", that's used in the manufacture of porcelain. There isn't that much of it around, it has to be mined, and it would definitely cost more that Coal Ash; so, while it might be an option, it's not one competitive with Coal Ash, or that could be used instead of Coal Ash in any kind of cost-effective way.)
The copper ion source may provide a bactericidal property to the geopolymer mortar. The geopolymer mortar may have a suitable viscosity for spray application. The geopolymer mortar may be formed by further mixing in one or more additives including, but not limited to, surfactants, thermal spheres, colloidal silicas, adhesion primers, and fibers.
The various embodiments of the geopolymer coating offer high corrosion resistance, bactericidal properties, low costs of production, and rapid and easy application. The geopolymer coating may have enhanced viscosity and surface tension suitable for its application as a mortar coating using manual or mechanical means.
The geopolymer coating may be used as a protective coating for the rehabilitation and reconstruction of concrete or brick surfaces of structures used for the transportation, storage, and treatment of wastewater streams from municipal and industrial sources including, but not limited to, pipes, manholes, wet wells, chambers, tunnels, diversion boxes, pump stations, drop structures, reservoirs, clarifiers, and primary and secondary retention and treatment basins. The geopolymer coating may also be used as a coating for tunnels and mine shafts where acidic conditions are the main source of deterioration of the supporting structures. The geopolymer coating may be applied using conventional techniques for cementitious linings including, but not limited to, spraying, pumping, flooding, and trowelling."
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And, here's a thought:
Even though they might not need the extra protection, you could build some, as above, "brick ... structures" out of brick or block made via the process disclosed in our report of:
West Virginia Coal Association | Coal Fly Ash Bricks are Greener and Stronger | Research & Development; concerning: "United States Patent 7,998,268 - Method to Produce Durable Non-vitrified Fly Ash Bricks and Blocks; 2011; Assignee: Ecological Tech Company, Inc., MO (formerly: "Freight Pipeline Company"); Abstract: A method of making durable, non-vitrified masonry units comprising fly ash, the method comprising mixing fly ash comprising a minimum of 15% Calcium Oxide (CaO) by weight and ... and an air entrainment agent to form a fly ash mixture; compacting the fly ash mixture in a shaping device by applying pressure of at least 1000 psi to the fly ash mixture; and curing the compacted fly ash mixture to cause the mixture to harden and gain strength. A method to produce durable, non-vitrified masonry units comprising fly ash";
and then seal those Coal Fly Ash brick structures up, protecting them and reinforcing them, by coating them with, as per the process of our subject herein, "United States Patent Application 20120156381 - Geopolymer Mortar and Method", a protective layer of "geopolymer" that is itself composed of "35% to about 45% by weight" "class C or class F fly ash".
And, in so doing, you could bring some badly needed income, and jobs, home to US Coal Country, by employing some people to mine the Coal Ash and then to form it into the blocks and into the, as herein, "geopolymer coating" for those Coal Ash blocks.
