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The leaching of mercury and other elements from asbestos-cement sheets in various environmental conditions

Klojzy-Karczmarczyk Beata, Mazurek Janusz

Gospodarka Surowcami Mineralnymi

2022

T. 38, z. 4

191--204

The leachability of pollutants from asbestos-containing waste, previously used for roofing was investigated. Laboratory tests were performed under static conditions (tests 1–20) in accordance with the TCLP methodology (with the use of acetic acid as the leaching medium, initial pH = 3.15). The maintaining of constant leaching conditions proved to be impossible at the experimental stage. Following the stabilization of conditions, the pH range for the obtained solutions increased to an average value of 8.3. Aluminum, boron, barium, cadmium, chromium, copper, iron, nickel, lead, strontium, zinc, and mercury were identified in the eluate. The low leachability of individual metals under the planned conditions was observed. In general, no leaching of such metals as cadmium, nickel, and lead was observed. The mercury content in the eluates is below the quantification limit, but the obtained values fall to around the limit of detection for the element. As compared with leaching with the use of distilled water (Klojzy-Karczmarczyk et al. 2021), zinc and boron additionally appear in eluates. The determined value of leachability for the individual analyzed elements increases from double to a few times with the use of the TCLP method. The value of leaching for barium is on average 5.56 mg/kg, for chromium it is 1.10 mg/kg, for copper 0.26 mg/kg, and for iron 0.80 mg/kg. In addition, the leaching of boron of around 3.00 mg/kg and of zinc 1.84 mg/kg was found. Higher leachability values were found only for strontium and aluminum. The leaching of strontium is on average around 62 mg/kg. While the leaching of aluminum is lower than values identified in the previous tests with the use of distilled water and is around 2.76 mg/kg. Products of leaching contain mainly pollutants characteristic of cement (aluminum, strontium, and iron).

Przeprowadzono badania wymywalności zanieczyszczeń z odpadów zawierających azbest, stosowanych wcześniej jako pokrycia dachowe. Przeprowadzono badania laboratoryjne w warunkach statycznych (test 1:20) zgodnie z metodyką TCLP (przy udziale roztworu kwasu octowego, jako medium ługujące, pH początkowe 3,15). Na etapie eksperymentu okazało się niemożliwe utrzymanie stałych warunków ługowania. Po ustabilizowaniu warunków zakres pH dla uzyskanych roztworów wzrasta do średniej wartości 8,3. W eluatach oznaczano glin, bor, bar, kadm, chrom, miedź, żelazo, nikiel, ołów, stront, cynk oraz rtęć. Obserwowana jest niska wymywalność poszczególnych metali w założonych warunkach. Nie obserwuje się generalnie wprowadzania do roztworów metali takich jak kadm, nikiel, ołów. Zawartość rtęci kształtuje się w eluatach poniżej granicy oznaczalności, ale uzyskane wartości mieszczą się w okolicach granicy wykrywalności tego pierwiastka. W porównaniu do ługowania z zastosowaniem wody destylowanej (Klojzy-Karczmarczyk i in. 2021) pojawia się w eluatach dodatkowo cynk oraz bor. Stwierdzona wielkość wymywania dla poszczególnych analizowanych pierwiastków wzrasta od 2 do kilku razy przy zastosowaniu metody TCLP. Wielkość wymywania dla baru wynosi średnio 5,56 mg/kg, chromu 1,10 mg/kg, miedzi 0,26 mg/kg, żelaza 0,80 mg/kg. Dodatkowo stwierdzono wymywanie boru na poziomie 3,00 mg/kg i cynku 1,84 mg/kg. Wyższe wartości wymywalności stwierdzono jedynie dla strontu i glinu. Wymywanie strontu kształtuje się na średnim poziomie 62 mg/kg. Natomiast wymywanie glinu jest niższe w porównaniu do wcześniejszych badań z zastosowaniem wody destylowanej i jest na poziomie 2,76 mg/kg. W produktach wymywania obecne są głównie zanieczyszczenia charakterystyczne dla cementu (glin, stront, żelazo).

Wpływ mineralnej karbonatyzacji na wymywalność zanieczyszczeń

Uliasz-Bocheńczyk A., Piotrowski Z.

Rocznik Ochrona Środowiska

2009

Tom 11

1083-1092

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.