Waste hadling project of a power generation waste producer - an approach to the environmentally oriented quality

摘要

The world annual production of energetical wastes (EW) achieves approximately 100 mil. Tons. If the present trend in the power production is to be maintained, it is necessary to search such methods of the EW's liquidation, which are environmentally favourable. It is supposed that the share of the coalbased power production in the following 20 - 25 years will be more than 20 percent out of the total power production, which is one of reasons, why the problems of the EW is to be studied intensively. This can be solved no only from the new point of view of the clean technologies, or the BAT - best available technologies, but also by adopting new criteria, changing the hierarchy of values, with interdisciplinary knowledge, so that the waste - the problem of present days - becomes the raw material of future.The Vojany power plant is the most important classic steam plant, burning fossil fuels, its installed capacity represents more than 20 percent of the SE, a.s. potential. In the plant it is burnt the semi-anthracite black coal in smelting boilers. After he burning remains almost 20 percent of ash out of the original amount. At present this ash (slag and fly ash from separators) is transported to the sludge bed. The content of residuals of non-burnt coal in the ash from smelting boilers is 8 percent and more. The average content of the residuals from the EVO Vojany is 28 percent of the loss by annealing (l.a). The content of the Fe component in the ash is in the extent of 3 - 10,2 percent, in the indirect dependence on the content of the l.a. The content of individual utility components gives assumptions for their successful separation. The procedure at the flotation separation of the residuals of non-burnt coal and the following lowintensity wet magnetic separation represents the technology that allows a complex utilisation of the ash.After the flotation of residuals of the non-burnt coal the chamber product - the flotation waste - was divided into two components:- the lighter one, formed by relatively stable suspension containing randomly non-flotated coal particles, but especially microspheres,- the heavier one was formed by settled heavy components, which were successively processed by the wet low-intensity magnetic separation.The achieved results are favourable. The flotation concentrate contained 70.87 percent of the l.a. at the weight yield of 24,60 percent. It means that in the feed into the flotation the utility component represents as much as 1/4 share. After the grinding the flotation concentrate can be recycled. The magnetic product after the third purifying - the magnetite concentrate - contained 42,42 percent of the Fe at the 6, 10 percent weight yield. After s ,,grinding" in the agate mortar the marbled concentrate grains were opened (liberalized) and again separated magnetically. The final concentrate contained 49 percent Fe, which is the content that meets the requirements for feeding into the processes of the raw iron or steel production. In such ash treatment method, verified in the model investigation, it is possible to remove the inadequately high l.a. content that excludes its direct utilization in the civil engineering. By removing this - for the direct ash utilization excluding component - it is gained ,, environmentally suitable" waste and ,,purified" ash, and utility raw materials - flotation concentrate of the residuals of non-burnt coal and the magnetite product.