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.
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.
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.
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!
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?
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.
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.