The decline of traditional heavy industries such as steel manufacture and coal mining have left certain areas with severe economic problems. Furthermore, the legacy of millions of tons of waste from these industries has not exactly enhanced the local environment.
Technology could provide a means to regenerate the economy of these blighted areas by creating industries utilising the accumulated waste.
How?
Conventional concrete uses Portland cement as a binder. Because the production of this material generates a lot of CO2, a number of alternatives are being investigated. One of these is the production of concrete using geopolymer. Geopolymers are made from aluminosilicate-containing materials such as coal ash, blastfurnace slag and mining refuse, by reaction with alkali.
Geopolymer concrete was used to construct Brisbane West Wellcamp Airport in Australia. The material has good strength and chemical resistance compared to conventional concrete. It is also very resistant to fire and can be used to immobilise toxic chemicals.
Now, the U.S. has abundant reserves of natural alkali (Trona) and mountains of aluminosilicate-based waste which could be used as the raw material for geopolymers.
How would this affect the railroads? There are already lines in potential production areas. The places where concrete is needed are often distant from these areas. Railroads are very good at moving large quantities of bulk materials. This all suggests that there would be potential new business for rail without the need for massive capital investment.
Check out the Saratoga and North Creek's efforts to haul mine tailings out of the Adirondacks...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Seems to me that the economics of this would be sketchy. Haul the trona from out west(?) to the northeast, make the geopolymer concrete, then ship it where concrete is needed? That's a lot of hauling of a lot of tons that would have to compete with cement plants from around the country.
Thanks to Chris / CopCarSS for my avatar.
One other problem is that geo-polymer concrete isn't widely accepted. Few, if any, state Depts of Transportation spec it. Without widespread acceptance and use, there isn't economic justification for large-scale transportation of raw materials.
rrnut282 One other problem is that geo-polymer concrete isn't widely accepted. Few, if any, state Depts of Transportation spec it. Without widespread acceptance and use, there isn't economic justification for large-scale transportation of raw materials.
Geopolymer is at this stage a new kid on the block and so is not widely accepted *yet*. It is the subject of investigations by university engineering departments around the world. The use of geopolymer concrete for the airport in Brisbane suggests that the material is gaining acceptance in the civil engineering community and over the next decade or so we may see a rapid increase in its production and use.
Murphy Siding Seems to me that the economics of this would be sketchy. Haul the trona from out west(?) to the northeast, make the geopolymer concrete, then ship it where concrete is needed? That's a lot of hauling of a lot of tons that would have to compete with cement plants from around the country.
Alkali appears to be used at less than 10% of the mass of the geopolymer binder which in turn forms about 20% of the mass of the finished concrete. Whether transport costs per ton would be prohibitive or not depends on many things, including the end-use of the material.
Geopolymer technology seems to be moving from the laboratory/prototype stage to early practical applications. Mass industrial use is still to come. It is too early to tell if the "rust belt" will benefit from an industrial renaissance but it would seem that it has the potential to do so.
It might be the case that some at least of the geopolymer produced would be used as the raw material for local manufacturing. This could include fire-resistant products for the construction industry as well as precast concrete items. In this case the cost of transportation would diminish in importance.
The title of my original post was necessarily left as a question, rather than a statement. Geopolymer technology *might* not provide an answer but it does raise interesting possibilities!
Island Man,
So you are suggesting that trona would be combined the industrial waste materials that you mention, thus manufacturing geopolymer concrete. You say this would ideally be done in the eastern rust belt because this is where the necessary industrial waste is located. Where is the trona located?
I assume that the trona would be mined in western states, so it would be hauled by rail to manufacturing plants in the rust belt. Then the railroads would also haul the finished geopolymer cement to geopolymer concrete plants all over the country.
How does the cost of geopolymer concrete compare to Portland cement concrete? What is the overall performance comparison of the two types of concrete?
Euclid Island Man, So you are suggesting that trona would be combined the industrial waste materials that you mention, thus manufacturing geopolymer concrete. You say this would ideally be done in the eastern rust belt because this is where the necessary industrial waste is located. Where is the trona located? I assume that the trona would be mined in western states, so it would be hauled by rail to manufacturing plants in the rust belt. Then the railroads would also haul the finished geopolymer cement to geopolymer concrete plants all over the country. How does the cost of geopolymer concrete compare to Portland cement concrete? What is the overall performance comparison of the two types of concrete?
Euclid,
There is a lot of material on the Net about geopolymers. You might find the following interesting:
www.claisse.info/2010 papers/k18.pdf
www.researchgate.net/publications/257390155_The_mechanical_properties_of_fly_ash_based_geopolymer_concrete_with_alkaline_activators
It appears to be possible to use sodium carbonate (from trona) rather than sodium hydroxide as the activator:
https://www.google.com/patents/WO2014075134A1?cl=en
Geopolymer concrete has been used to make prototype railroad ties:
www.rtri.or.jp/eng/rd/seika/2012/02/02_06.html
Fire resistance of geopolymers:
www.aerodefensetech.com/component/content/article/adt/tech-briefs/materials/8261
...and their use in remediating uranium mine tailings in Germany:
https://www.geopolymer.org/applications/geocistem
I would guess that manufacture of precast concrete items and fire-resistant products would be the initial consumers of geopolymer, with more general use by the (understandably) cautious construction industry following later.
Geopolymer needs less 'work' done to prepare it compared to Portland cement. To make Portland cement you normally need to quarry and crush rocks such as limestone or chalk. The raw materials then need to be heated in a kiln to about 1450 C, after which the clinker needs to be ground to a powder. The manufacturing plant is a significant capital investment. Geopolymer using waste materials normally doesn't need much more than a mixing plant.
Some of the raw materials that can be used for geopolymer actually have a negative value because unused they impose a cost. Coal mine waste tips can produce acid runoff from sulfides they contain, can ignite and smoulder for decades and are prone to collapse. Finding a use for this material would ameliorate these problems.
Seems like a great idea to me, and estasblished companies that are adopting this approach would seem to be good investments.
daveklepper Seems like a great idea to me, and estasblished companies that are adopting this approach would seem to be good investments.
Portland Cement supplies are beginning to stabelize, since the completion of the 'Three Gorges Dam', which had the Chinese buying as much Portland Cement they could get. Out here many of themanufacturers of Portland Cement had it placed on 'allotments' to their regular, bulk purchasers.
'Fly Ash' [ produced at coal burning facilities] became the additive of choice [roughly 1 lb of Portland to 1.5 lb of fly ash.] here in Kansas; due to its availability. It stands to reason that there would be experimentation with any product that would extend Portland Cement, and even enhance its qualities.
http://www.zeobond.com/geopolymer-solution.html
FTL: [snip]"... The main process difference between OPC and geopolymer cement is that OPC relies on a high-energy manufacturing process that imparts high potential energy to the material via calcination. This means the activated material will react readily with a low energy material such as water. On the other hand, geopolymer cement uses very low energy materials, like fly ashes, slags and other industrial wastes and a small amount of high chemical energy materials (alkali hydroxides) to bring about reaction only at the surfaces of particles to act as a glue.."[snipped]
Something that might be worth considering, though, is that much of the potentially hazardous waste from boiler maintenance, including cleanings that used inhibited HF, was admixed with "waste" ash for many years under a specific DEP waiver. It is possible that many politicians or 'businessmen seizing an environmental opportunity' might not understand or recognize this (or that, as with some other kinds of environmental-remediation action, a company might make substantial capital investment, or drive competition out of a crowded market, only to be hit with directives to perform what might be cost-effectively ruinous levels of testing/monitoring and 'remediation' on a large percentage of potential geopolymer-concrete feedstock.
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