United States Patent: 8043548
We've previously reported on the work of Iowa State University, in the development of technologies that would serve to enable the more productive utilization of the solid byproducts that arise from our essential use of Coal in the generation of truly abundant and genuinely affordable electrical power.
Recently, we saw, in:
West Virginia Coal Association | Coal Ash Reinforced Recycled Plastic | Research & Development; concerning: "US Patent 6,583,217 - Composite Material Composed of Fly Ash and Waste PET; 2003;
Assignees: Iowa State University and The University of Missouri; Abstract: A composite material and method are described wherein melted waste, chemically unmodified PET material and fly ash particles are mixed in a vessel to disperse fly ash particles in the melted PET material. The resulting mixture then is cooled to solidify the melted PET material to form a composite material having a matrix comprising PET and dispersoids distributed in the matrix and comprising fly ash particles";
that, Iowa State University had developed a way in which a pernicious type of waste plastic could be recycled and converted into a useful raw material by combining it with Coal Ash.
And, herein we see that they further refined those technical concepts, not only devising an improved blend of waste or scrapped PET plastic and Coal Ash, but, a manufacturing method in which that Coal Ash-plastic blend could be processed in the manufacture of a specific, value-added product.
Comment follows, and is inserted within, excerpts from the initial link to:
"United States Patent 8,043,548 - Polymer Mortar Composite Pipe Material and Manufacturing Method
Date: October, 2011
Inventor: David White, Iowa
Assignee: Iowa State University Research Foundation
Abstract: Composite material and plunger-cast pipe manufacturing method and system wherein the composite material includes waste, chemically unmodified PET material, one or more waste filler materials (e.g. ... waste coal combustion by-products), and fiber reinforcement (e.g. glass, metal, ceramic, carbon, organic, and polymer fibers) and wherein the PET material is melted and mixed in a container to disperse filler material and fiber reinforcement in the PET material. The resulting mixture can be formed into a tubular pipe shape using the plunger-cast manufacturing method and system wherein a plunger piston and inner collapsible mold are pushed into the melted composite material contained in an outer mold. When cooled and solidified in the mold, a composite material having a matrix comprising PET with filler material and fiber reinforcement distributed in the matrix is formed in the shape of a tubular body.
(We note that David White at this point cites a surprisingly large body of prior references concerning such and similar plastic and Coal Ash composites, including the above-noted "US Patent 6,583,217 - Composite Material Composed of Fly Ash and Waste PET". And, it is, in fact, surprising to discover just how much of this sort of work, in the productive utilization of Coal Ash, has gone on; totally, it seems, unacknowledged and unheralded by the Coal Country press and, thus, unknown to the Coal Country public.)
Claims: A method of making a tubular pipe body, comprising introducing a flowable material in an outer mold, disposing an inner collapsible mold on a plunger piston, said inner collapsible mold having a smaller transverse dimension than the outer mold, relatively moving the inner collapsible mold on the plunger piston and the outer mold with the material therein to cause the material to flow into a space between the outer mold and the inner mold such that it can form a tubular pipe body in said space between the outer mold and the inner collapsible mold, removing the plunger piston to leave the inner collapsible mold in place, and forming the tubular pipe body from the material in said space.
(Again, this innovative technology is more about how we can go about using Coal Ash-plastic blends, than it is about the Coal Ash-plastic blends themselves. The point seeming to be, that: of course we can make a perfectly-acceptable reinforced plastic by using Coal Ash, and, here's how we can do a better job of using that Coal Ash and plastic composite blend.)
The method ... wherein the flowable material comprises a melted composite material comprising melted waste, chemically unmodified PET material; one or more waste solid filler materials, and solid fiber reinforcement.
(Note, that, as in the above-cited "US Patent 6,583,217", it is "waste, chemically unmodified PET material" that is specified for use herein, thus again indicating that our Coal Ash can enable the productive use and consumption of something that might otherwise be tossed away, or used in a less-valuable fashion.)
The method ... further including preheating the outer mold and inner collapsible mold before the material is introduced (and) collapsing the inner collapsible mold in a manner to reduce its transverse dimension and allow its removal from the tubular pipe body.
The method ... including removing the outer mold and the inner collapsible mold from the tubular pipe body.
Background and Field: The present invention provides polymer mortar composite materials including recycled, post-consumer waste polyethylene terephthalate (PET) with waste filler materials and fiber reinforcement and methods of their manufacture and methods of their use as pipe in the construction industry.
Diverting solid waste from landfills is increasingly important due to limited availability of landfill space, rapidly increasing landfill cost, and environmental threats.
The U.S. is the largest global producer of PET containers at nearly 70 percent of the supply ... . In the U.S., estimates indicate that annual production of PET containers will reach more than 2 million tons ... . The recycling rate for PET is about 25 percent ... .
Production of the waste filler materials is about ... 100 million tons for coal-combustion by-products.
Recycling has emerged as the most practical method to deal with these high-volume waste problems.
In addition, the U.S. has about 19,782 sewerage systems serving about 170 million people or about 75 percent of the population ... . As with much infrastructure in this country, this subterranean component has also deteriorated due to normal aging, sulfuric acid degradation, under design, poor initial design, and minimal maintenance. It is estimated that 800,000 miles of sanitary sewer line in the U.S. are in need of rehabilitation and that we are currently making repairs at the rate of 2 percent per year ... . Sixteen thousand miles of rehabilitation with an estimated 8 thousand miles of new construction create a need for improved pipe material.
An object of the invention is to provide a polymer mortar composite pipe material that has several beneficial material properties over conventional Portland cement concrete (PCC) pipe and vitrified extra strength clay tile including high structural capacity, excellent acid resistance, and low density. Equally important is the fact that the material components of the polymer mortar composite formulation consist of recycled plastic and waste filler materials (... various coal combustion by-products). By using recycled, post-consumer waste polyethylene terephthalate (PET) instead of virgin plastic, which is petroleum derived material; use of a significant volume of crude oil can be reduced.
Another object of the invention is to provide a plunger-cast manufacturing method and system than can increase recycling through production of polymer mortar composite pipe using the composite material mixtures described herein.
Still another benefit of the invention derives from production of the polymer mortar pipe to provide a strong, lightweight, and durable pipe product for which there is currently tremendous need.
Summary: The present invention provides a composite material and plunger-cast pipe manufacturing method and system wherein the composite material comprises waste, chemically unmodified PET material, one or more waste filler materials (e.g. ... coal combustion by-products), and fiber reinforcement (e.g. glass, metal, ceramic, carbon, organic, and polymer fibers). The PET material is melted and mixed with the other constituents in a container to disperse the waste filler material and the reinforcement fibers in the PET material. The resulting mixture can be formed into a tubular pipe shape using the plunger-cast manufacturing method and system pursuant to an embodiment of the invention wherein a piston and an inner collapsible mold thereon are pushed into the melted composite material contained in an outer mold. When cooled and solidified in the mold, a composite material having a matrix comprising PET with filler material and fiber reinforcement distributed in the matrix is formed in the shape of a tubular body. The plunger-cast pipe manufacturing method and system can be used with other materials as well and is not limited to the composite material described above.
In one embodiment of the invention, the solid waste, chemically unmodified PET material, waste filler particles and fiber reinforcement are premixed and placed in a melting container for melting of the PET material while the mixture is mixed or stirred. Alternately, the solid waste, chemically unmodified PET material can be melted in the container, and pre-heated waste filler particles introduced to the melted PET material with the mixture stirred or mixed. Once the PET/filler mixture is homogenized, the fiber reinforcement is incrementally added to the mixture and stirred or mixed. The mixture of melted PET material, waste filler particles and fiber reinforcement can be molded, extruded or otherwise formed.
The invention envisions use of waste PET material from recycled beverage bottles and other sources. In practice of the invention, the recycled waste PET material is not chemically modified in any way prior to melting. The solid recycled waste PET material may be washed in tap water and shredded or otherwise comminuted prior to melting.
The invention envisions use of ... coal-combustion byproducts and/or other waste filler materials with comparable morphological characteristics.
Various amounts of filler material up to about 70 percent (based on weight of PET) in combination with various amounts of fiber reinforcement up to about 6 percent (based on weight of PET and waste filler) can be included in the composite material. Preferably, the waste filler content of the composite material is at least about 50 percent and fiber content preferably from about 1 to about 4 percent."
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Again, unclassified waste or scrap PET plastic wouldn't likely find reuse in beverage containers or drinking water pipes, nor would PET reinforced and filled with Coal Ash.
However, as in "800,000 miles of sanitary sewer line in the U.S. are in need of rehabilitation", or replacement, there exists an extraordinary outlet for a reinforced plastic pipe that can serve as a better performing substitute for, and one which "has several beneficial material properties over", "conventional Portland cement concrete (PCC) pipe and vitrified extra strength clay tile", "including high structural capacity, excellent acid resistance, and low density".
As herein, that plastic beverage bottle you just drained on your way home from a shift at the mine can serve, when mixed with some of the Ash from the Coal you just spent the last eight hours helping to get out of the ground, as an environmentally and economically beneficial, better-performing substitute sewer pipe manufacturing material, relative to the alternatives; one which will do a better job of resisting "sulfuric acid degradation" while serving in it's intended application; after having prevented the importation of a "significant volume of crude oil", which might otherwise have been required to manufacture such better-performing sewer pipe from virgin plastic material.
