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It is well known that it takes long time to stabilize landfill and meet the standard for leachate after landfilling is stopped. Moreover, the time required to meet the standard is not predicted. In this research, the rapid small-scale column test (RSSCT) was applied and was found to predict the dissolved organic carbon (DOC) leaching from municipal solid waste incineration bottom ash in a simulated landfill site. Acid washing with hydrochloric acid remarkably reduced the DOC leaching from bottom ash. According to the RSCCT, it was estimated that the acid washing would reduce the time for DOC stabilization of bottom ash by about 80% in a simulated landfill situation.

Spent adsorbents for oxyanion forming elements and heavy metals are classified as hazardous materials and they are typically treated by stabilization/solidification before landfilling. The use of lime or cement for stabilization/solidification entails a high environmental impact and landfilling costs are high. This paper shows that mixing spent adsorbents in the raw material for the production of ceramic materials is a valuable alternative to stabilize oxyanion forming elements and heavy metals. The produced ceramics can be used as construction material, avoiding the high economic and environmental impact of stabilization/solidification followed by landfilling. To study the stabilization of oxyanion forming elements and heavy metals during the production process, two series of experiments were performed. In the first series of experiments, the main pollutant, Mo was adsorbed onto iron-based adsorbents, which were then mixed with industrial sludge (3w/w%) and heated at 1100°C for 30min. Mo was chosen, as this element is easily adsorbed onto iron-based adsorbents and it is the element that is the most difficult to stabilize (i.e. the highest temperatures need to be reached before the concentrations in the leachate are reduced). Leaching concentration from the 97/3 sludge/adsorbent mixture before heating ranged between 85 and 154mg/kg; after the heating process they were reduced to 0.42-1.48mg/kg. Mo was actually stabilized, as the total Mo concentration after addition was not affected by the heat treatment. In the second series of experiments, the sludge was spiked with other heavy metals and oxyanion forming elements (Cr, Ni, Cu, Zn, As, Cd and Pb) in concentrations 5 times higher than the initial concentrations; after heat treatment the leachate concentrations were below the regulatory limit values. The incorporation of spent adsorbents in ceramic materials is a valuable and sustainable alternative to the existing treatment methods, saving raw materials in the ceramics production process and avoiding the use of stabilizing agents. Besides, spent adsorbents added to the raw material for ceramic products, may improve their aesthetic and structural properties. publisher: Elsevier articletitle: Recycling of spent adsorbents for oxyanions and heavy metal ions in the production of ceramics journaltitle: Waste Management articlelink: http://dx.doi.org/10.1016/j.wasman.2015.07.006 content_type: article copyright: Copyright © 2015 Elsevier Ltd. All rights reserved. ispartof: Waste Management vol:45 pages:407-11 ispartof: location:United States status: published

This work describes the leaching behavior of potentially hazardous metals from three different clay-based industrial ceramic products (wall bricks, roof tiles, and face bricks) containing foundry sand dust and Waelz slag as alternative raw materials. For each product, ten mixtures were defined by mixture design of experiments and the leaching of As, Ba, Cd, Cr, Cu, Mo, Ni, Pb, and Zn was evaluated in pressed specimens fired simulating the three industrial ceramic processes. The results showed that, despite the chemical, mineralogical and processing differences, only chrome and molybdenum were not fully immobilized during ceramic processing. Their leaching was modeled as polynomial equations, functions of the raw materials contents, and plotted as response surfaces. This brought to evidence that Cr and Mo leaching from the fired products is not only dependent on the corresponding contents and the basicity of the initial mixtures, but is also clearly related with the mineralogical composition of the fired products, namely the amount of the glassy phase, which depends on both the major oxides contents and the firing temperature. (C) 2015 Elsevier B.V. All rights reserved.

International audience; Electric arc furnace slag (EAF) has the potential to be re-utilized as an alternative to stone material, however, only if it remains chemically stable on contact with water. The presence of hydraulic phases such as larnite (2CaO SiO2) could cause dangerous elements to be released into the environment, i.e. Ba, V, Cr. Chemical treatment appears to be the only way to guarantee a completely stable structure, especially for long-term applications. This study presents the efficiency of silica addition during the deslagging period. Microstructural characterization of modified slag was performed by SEM and XRD analysis. Elution tests were performed according to the EN 12457-2 standard, with the addition of silica and without, and the obtained results were compared. These results demonstrate the efficiency of the inertization process: the added silica induces the formation of gehlenite, which, even in caustic environments, does not exhibit hydraulic behaviour.

Carcinogenic chromates are phased out as corrosion inhibitors in organic coatings, and are replaced by benign alternatives. Cerium-based compounds are excellent corrosion inhibitors in an aqueous environment. However, whether they are effective as corrosion inhibitor in an organic coating also depends on their interaction with the coating matrix, which should result in a sufficient release of inhibitors over a desired period of time. In this work we report on the leaching of cerium dibutylphosphate, Ce(dbp)3, from an epoxy coating system as a first step toward a fundamental understanding of the leaching behavior. To this end, coating systems containing various levels of inhibitor loading, ranging from 1 up to 50 wt%, were fabricated. These coatings were characterized using Fourier transform spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). Leaching experiments were performed by exposing the coating films to water, while the concentration of dissolved Ce(dbp)3 in this water was monitored in situ using ultraviolet-visible (UV-vis) spectroscopy. The leaching of inhibitors showed a clear dependence on the initial inhibitor loading of the coating system. For highly loaded coatings (>25 wt%) all inhibitors leach out, whereas for a low loading level (

Carcinogenic chromates are phased out as corrosion inhibitors in organic coatings, and are replaced by benign alternatives. Cerium-based compounds are excellent corrosion inhibitors in an aqueous environment. However, whether they are effective as corrosion inhibitor in an organic coating also depends on their interaction with the coating matrix, which should result in a sufficient release of inhibitors over a desired period of time. In this work we report on the leaching of cerium dibutylphosphate, Ce(dbp)3, from an epoxy coating system as a first step toward a fundamental understanding of the leaching behavior. To this end, coating systems containing various levels of inhibitor loading, ranging from 1 up to 50 wt%, were fabricated. These coatings were characterized using Fourier transform spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). Leaching experiments were performed by exposing the coating films to water, while the concentration of dissolved Ce(dbp)3 in this water was monitored in situ using ultraviolet-visible (UV-vis) spectroscopy. The leaching of inhibitors showed a clear dependence on the initial inhibitor loading of the coating system. For highly loaded coatings (>25 wt%) all inhibitors leach out, whereas for a low loading level (

Leaching behavior and surface alteration of the solid form products immobilizing Cs have been studied under hydrothermal conditions. Leached percentage of Si and Cs in distilled water at 90℃ increased with leaching time, while leaching rate gradually declined. The concentration of Al temporarily reached supersaturation and then markedly fell with leaching time, corresponding to the precipitation of Al-rich particles. Leached percentage of Cs in salt solutions at 200℃ was in the order of NaCl>>KCl>MgCl_2>>CaCl_2,and those of Si and Al were below 3%. A considerable alteration of solid form was observed in NaCl solution; precipitated layer, altered layer and reaction layer were built up on the surface. Leached percentage of Cs was found to be 0.14% in the coexisting system of equilibrated water/buffer・canister materials.

This study investigated a strategy of blending lead-laden sludge and Al-rich precursors to reduce the release of metals from the stabilized products. Using PbO as the simulated lead-laden sludge to sinter with γ-Al2O3 by Pb:Al molar ratios of 1:2 and 1:12, PbAl2O4 and PbAl12O19 were formed as final products during the sintering process, respectively. By firing the PbO + γ-Al2O3 mixtures with different Pb/Al molar ratios at 600 to 1000 °C, the lead transformation was determined through X-ray diffraction (XRD) data. In Pb/Al molar ratio of 1/2 system, the formation of PbAl2O4 is initiated at 700 °C, but an effective formation was observed above 750 °C. An intermediate phase, Pb9Al8O21, was detected in the temperature range of 800-900 °C. However, different incorporation behavior for sintering PbO with Al-rich precursors at a Pb/Al molar ratio of 1/12 was observed during the formation of PbAl12O19 in this system. In the sintering process, both temperature and time effect on the formation of PbAl2O4 and PbAl12O19 phases were estimated. Finally, a prolonged leaching test modified from the U.S. Environmental Protection Agency-s toxicity characteristic leaching procedure (TCLP) was used to evaluate the durability of PbO, Pb9Al8O21, PbAl2O4 and PbAl12O19 phases. Comparison for the leaching results of the four phases demonstrated the higher intrinsic resistance of PbAl12O19 against acid attack., {"references":["R. Jalali, H. Ghafourian, Y. Asef, S. J. Davarpanah, S.Sepehr, \"Removal\nand recovery of lead using nonliving biomass of marine algae.\" Journal of\nHazardous Materials, vol. 92(3), pp. 253-262, 2002.","V. K. Gupta, M. Gupta, S. Sharma, \"Process development for the removal\nof lead and chromium from aqueous solutions using red mud - An\naluminium industry waste.\" Water Research, vol. 35(5), pp. 1125-1134,\n2001.","K. Conrad, H. C. 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Solidification/stabilization (S/S) of automotive phosphate coating sludge (PS) containing potentially toxic heavy metals was studied. The hazardous characteristics of this waste were assessed according to both Turkish and U.S. Environmental Protection Agency (EPA) regulations for hazardous solid waste. Unconfined compressive strength (UCS) and leaching behavior tests of the solidified/stabilized product were performed. Solidification studies were conducted using Portland cement (PC) as the binder. UCS was found to decrease with increasing waste content It was found that recovery of the waste for construction applications was possible when the waste content of the mortar was 20% and below, but solidification for safe disposal was achieved only when higher waste concentrations were added. Cu, Cr, Ni, Pb and Zn were found to be significantly immobilized by the solidification/stabilization process. Ni and Zn, which were present at particularly high concentrations (2.281 and 135.318 g/kg respectively) in the PS, had highest the retention levels (94.87% and 98.74%, respectively) in the PC mortars. The organic contaminants and heavy metals present in PS were determined to be immobilized by the S/S process in accordance with the BS 6920 standard. Thus, the potential for hazardous PS waste to adversely impact human health and the environment was effectively eliminated by the S/S procedure. We conclude that S/S-treated PS is safe for disposal in landfills, while recovery of S/S-treated PS constituents remains possible. Bursa Çimento Fabrikası A. Ş. Bursa Beton

Growing environmental concern is promoting the necessity of additional ceramic tests. The use of unknown materials with potential contamination conditions requires further studies to demonstrate that the piece encapsulates the pollutant and that during its firing it does not produce the emission of harmful volatile elements. The objective of this work was to perform both tests in a ceramic paste made with slip-casting wastes and electro-plating residues. The leaching methods for determining the encapsulation of potential harmful elements were performed following the TCLP, EP-Tox norm. Having precise chemical analysis of both crude and fired brick, the problem of emissions losses during the firing can be solved by the gain/loss techniques used in geological studies. In particular, the Isocon method that permits a quick visualization of the lost elements is useful. Once the volatile elements were determined, their amount was calculated considering a constant element and the chemical concentrations normalized by the loss of ignition, or using the crude/fired brick ratio densities. The leaching tests indicate that the ceramic brick does not produce harmful leachates according to Argentinean specifications. The leachates of B and Ca are high. Ca does not seem to be a problem while the B content is beyond the permitted limits. During the firing, volatilized elements are Ag, Br, Cl, F, Hg, S, Se, and H 2O. The loss of Ag, Br, and Se are negligible. For F and Cl the potential emission rate is very low (100 mg/kg) while in the case of S, the 2,600 mg/kg rate is high. However, extrapolated emission rates at the chimney assuming an air-to-brick ratio of 2.5 N m 3/kg, are approximately 1,040 mg/N m 3 for S and 40 mg/N m 3 for F and Cl, falling inside environmentally acceptable values. The geochemical procedures proved to be useful tools to assess the element mobilization during firing of ceramic wares and in the analyzed case, the results indicate that the paste is environmentally acceptable. Fil: Dominguez, Eduardo Alejandro. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentina Fil: Dondi, Michele. Instituto di Scienza e Tecnologia dei Materiali Ceramici; Italia Fil: Iglesias, Claudio. Piedra Grande S.A.; Argentina

Bei der Verbrennung (ca. 1000 °C) von Hausmüll und gewerblichen Müll fallen Schlacken an. Während ihrer Deponierung laufen exotherme Alterationsprozesse (u. a. Metallkorrosion, Verfestigungsprozesse) ab. Die Deponien erwärmen sich bis auf 90 °C, dies kann die Deponieabdichtung gefährden. Im Rahmen der vorliegenden Arbeit wurden frische und gealterte Schlacken ingenieurgeologisch, geochemisch und mineralogisch untersucht. Die Charakterisierung erfolgte über die Erfassung der chemischen Gesamtzusammensetzung, des Phasenbestandes und der chemischen Zusammensetzung der einzelnen Schlackenphasen sowie indirekt über das Elutionsverhalten. Zur Klärung der Alterationsvorgänge wurden detaillierte Studien zum Abbau des ursprünglichen Phasenbestandes, zur Phasenbildung sowie zum Bezug von Eluat zu den festen Phasen in Abhängigkeit der Lagerungsbedingungen und –dauer durchgeführt. Die gewonnenen Daten waren die Grundlage für die Modellierung einer Stoff- und Wärmebilanz des Modellsystems „Schlacke“ bezogen auf ein offenes und abgeschlossenes System und zu Änderungsvorschlägen der Deponierungstechnik. MSWI bottom ash is the residue of waste combustion processes at temperatures about 1000 °C. After quenching in a water reservoir the bottom ash is deposited in a landfill. As a result of exothermic alteration processes increased temperatures up to 90 °C could be observed in MSWI bottom ash landfills. Due to the high temperatures the stabilization of the landfill bottom liner system can be weakened. In this study fresh and alterated bottom ash material was physically, geochemically and mineralogically studied. The characterization resulted from the determination of the bulk composition, from the identification of the different bottom ash phases and their chemical composition. To clarify the alteration processes the decomposition of the bottom ash phases was characterized and the newly formed phases were identified. Additionally, leaching experiments were carried out according German DIN 38414-S4. The experiments supplied informations about the mobilization of different chemical components ( e.g. heavy metals) as well as about the stabilization of the different phases. The obtained data were the fundamentals of the modelling of a heat- and compound-balance-sheet applied to a open and closed system. Based on these results a practicable proposals for storage and emplacement were developed.

A granular material (GM) to be used as road sub-base was formulated using 80% of weathered bottom ash (WBA) and 20% of mortar. The mortar was prepared separately and consisted in 50% APC and 50% of Portland cement. A pilot-scale study was carried on by constructing three roads in order to environmentally evaluate the performance of GM in a real scenario. By comparing the field results with those of the column experiments, the overestimations observed at laboratory scale can be explained by the potential mechanisms in which water enters into the road body and the pH of the media. An exception was observed in the case of Cu, whose concentration release at the test road was higher. The long-time of exposure at atmospheric conditions might have favoured oxidation of organic matter and therefore the leaching of this element. The results obtained showed that immobilization of all heavy metals and metalloids from APC is achieved by the pozzolanic effect of the cement mortar. This is, to the knowledge of the authors, the only pilot scale study that is considering reutilization of APC as a safe way to disposal.