The use of fly ash and the products derived from fly ash should be considered in parallel with the question about what brand of coal ash was obtained. Hereafter, it will only dry fly ash, not in contact with water.
It is a little about coals.
In Russia there are some large coal basins.
The Kuznetsk coal basin
(the Kemerovo area) is one of the largest coal deposits of the world. On quality coals are various and are among some the best coals. Coals contain in penetrating horizons: ashes of 4-16 %, a moisture of 5-15 %, phosphorus to 0,12 %, volatile matters of 4-42 %, 0,4-0,6 % are grey; of 7000-8600 kcal/kg (29,1-36,01 MDZH/KG) possess combustion heat; coals lying down near to a surface, are characterised by higher moisture content, ashes to 30 % and the depressed maintenance of sulphur.
The East Siberian coals
The Irkutsk coal basin is located in a southern part of Irkutsk area.
The Minusinsk coal basin, is located in the Minusinsk hollow (republic Khakassia). Largest of them concern the Montenegro and Izyhsky coal deposit. In basin of 31-37 MDZH/KG prevail stone coals with combustion heat. The maintenance are grey seldom exceeds 1 %. Thus the maximum ash content (11-29,7 %) is characteristic for coals of the Izyhsky deposit, minimum (6,6-17,8 %) - for coals of the Bejsky deposit.
Kansko-Achinsk coal basin
Is in Krasnoyarsk region, the basin possesses the most significant stocks of the power brown coal extracted in basic open in the way.
Ash content on the average makes 7 - 14 %, heating value 2800 - 3800 kcal/kg.
The Ekibastuzsky coal basin
(Kazakhstan) is one of the most significant on stocks and wins first place in the world on coal density: on the area of 62 square kilometres coal stocks are estimated in 13 billion tons or 200 tons on one square metre. And on a coal mining in the open way is one of the most perspective areas in the world. Ash content of the mineral coals entering to Russia on the enterprises of power, reaches 40-50 %. The basic consumers of coal from this басcейна are in Urals Mountains.
Depending on degree of carbonification (metamorphism) there are brown coals, mineral coals and anthracites. The lowest combustion heat at brown coals, and the highest - at anthracites. The most favourable relation of the price and specific combustion heat have mineral coals. Coals of marks Д, G and anthracites find the application, as a rule, in boiler-houses. Coals of marks СС, OS, Т are applied to reception of electric energy since they have the big combustion heat, but burning of the yielded kind of coals is connected with certain technological complexities which are justified only in case of need uses of a considerable quantity of coal. In ferrous metallurgy G marks, for production of steels and pig-iron are used routinely.
Depending on a kind of coal, its deposit, a place and a way of burning on a yield absolutely different ashes are received.
Ashes, received from brown coals
Kansko-Achinsk basin, have very much a more potential in building branch, as comprise a considerable quantity (to 40-50 %) the cindery knitting. Knitting, evolved from lignite ashes almost ideally approaches for production of all spectrum of easy and especially easy concrete: foam concretes, aerocretes etc.
Unique minus cindery knitting is presence of free calcium which serves as a time lag action mine. Not having removed free calcium you risk to receive self-collapsing building materials, removal of free calcium occurs by addition of solution CaCl2 of 1 %. Also in lignite ashes magnetite to 3-5 %, applied as filler for especially heavy concrete, or as raw materials for metallurgy contains. Remained of fly ash products have value of sand, the unburnt coal can be directed on repeatedly to a copper.
Ashes of mineral coals
The ashes, received from burning of mineral coals (Especially Kuznetsk basin) have absolutely other composition and products.
Use of ashes of mineral coal without processing in the building industry is at the moment similar to use of gold-bearing sand in plaster and solutions.
It is connected with more difficult chemical and physical fly ash in which there are microspheres of the most different characteristics on density, to the size, colour. In the world there is a whole industry of production of artificial microspheres for various appendices. Thus, the price for the microspheres received by artificial methods, reaches to 15 Euros for kg.
Thus, ash disposal are as a matter of fact a technogenic deposit of valuable products.
The reason why on in the Western countries do not evolve microsphere, absence commercial advantage technologies of division of fly ash on fraction serves, even now there there is no understanding, what for it is necessary to manufacture ablation ashes. From the middle of 20 centuries it was accepted to use ashes of ablation as additives to cement, concrete, huge volumes have left at building of roads, landscape designing. On it ideas in the West are practically settled. Some shifts are under appendices in the field of polymers, but upon out of the building industry very small percent from all manufactured ashes of ablation is applied.
So, the basic composition of coal ash:
Easy aluminosilicate cenospheres - 1-2 %
Microspheres (basic composition SiO2, Al2O3, Fe3O4) - 80-85%
Coke - from 1 to 7 %
Magnetite in the spherical form - 3 %
Other minerals of 2 %
Running start on the size of all microspheres set forth above makes from 1 micron to 150-200 microns.
Depending on the characteristics (the size, density, true density, hardness, colour) microspheres at the expense of the unique properties can be applied with success in following appendices:
Coating compositions - instead of a used chalk, TiO2, quartz and other fillers, in quality thermoprotect filler for production of "warm" paints
Plasters, dry blends, glues, mastics - instead of sand and plastifiers
Practically any industrial rubber goods, polyurethane products and coverings - as filler
Special concrete, chisel solutions - as the filler, allowing to raise fluidity
Plastics and plastic, polymers, composit materials - as filler
Differences of microspheres from other fillers:
Ideal or nearly so the spherical form of all particles, a high level of hardness, hardness (not for easy aluminosilicate microspheres), various variants on density (from 0,8 to 1,5), colours basically transparent, at presence mullite - white, colour - depending on the iron maintenance.