Wpływ mineralnej karbonatyzacji na wymywalność zanieczyszczeń

Mineral sequestration is one of the methods of reducing the anthropogenic emission of CO2. Sequestration of CO2 via mineral carbonation is an ecologically safe method, since the ongoing processes result in products that are thermodynamically stable and neutral to the environment, in the form of carbonates, while the process of mineral carbonation through CO2 bonding in natural mineral resources and concrete is a phenomenon occurring in nature. At the same time, it may be used to reduce the leachability of impurities from waste. The employment of mineral carbonation in order to reduce the leachability of impurities from fly ash seems particularly interesting, as, at present, the ash is scarcely used in economy. Thus, CO2 reduction may be limited as well as leachability of impurities from waste, partly solving the problem of its deposition. The literature on leachability of fly ash after its prior mineral carbonation has been reviewed in the paper. The conditions of performing the process of carbonation by different authors have also been presented. The authors have shown the findings on three selected fly ash types from Polish power industry prior to and after their carbonation. The process of carbonation was carried out at a research station assembled specially for this purpose. The impact of mineral carbonation use on leachability of impurities from ash-aqueous suspensions has been presented. In the paper, the findings on leachability of the following chemical impurities have been revealed: Zn, Cu, Pb, Ni, As, Hg, Cd, Cr, Cl-, SO4 -2 from ash-aqueous suspensions, with compositions based on fly ash from hard coal combustion in Jaworzno and Lublin heat and power plants, from lignite combustion in Bełchatów power plant, as well as pH and chemical oxygen demand (COD) in leachates from ash-aqueous suspensions. The insertion of CO2 caused the reduction of leachability of Zn, Cu, Cr in case of all the three researched ash types. The obtained results have been compared with the requirements of PN-G-11011 standard 'Materials for solidified stowage and groutingof cavings' in the Regulation of Minister of Environment, 29th November 2002, on requirements to meet while entry to waters or soil of sewage, as well as on substances specifically harmful for the water environment and the Regulation of Minister of Environment, 27th November 2002, on conditions that surface waters employed as the sourceof drinking water are subject to. The findings on leachability only in certain cases do not meet the requirements of PN-G-11011 standard as well as the previously mentioned Regulations. The method of mineral carbonation is particularly interesting, since it may be used not only for CO2 sequestration, but also for limiting the leachability of ash from waste incineration, which may soon become, due to its amounts caused by increasing waste mass, the waste difficult to manager and which, above all, will be landfilled. This article is a preliminary publication signalizing the idea of leaching stabilization by mineral carbonation.