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Industrial activities generate different types of waste, with varying chemical properties. An investigation of the detailed chemical and mineralogical characteristics of these materials may serve as a first step for selecting an appropriate treatment or safe disposal method. This study focuses on arsenic (As) and heavy metals (i.e., Cd, Co, Cu, Cr, Mo, Ni, Pb, and Zn) in three sludge samples derived from industrial wastewater treatment plants in Southern Vietnam. The emphasis is on determining the influence of changing environmental conditions on element mobilization based on a multidisciplinary approach using sample micro analysis (Field Emission Gun Electron Probe Micro Analysis (FEG-EPMA)) in combination with different types of leaching/extraction tests. ispartof: pages:107-108 ispartof: Interfaces Against Pollution -Environmental Challenges & Opportunities- Book of abstracts pages:107-108 ispartof: Interfaces Against Pollution (IAP 2016) location:Lleida (Spain) date:4 Sep - 7 Sep 2016 status: published

After being used as an abrasive agent, copper slag is considered a solid waste in Vietnam because appropriate waste treatment techniques and effective management options are not available. This classification as solid waste is mainly due to the fact that the blasted copper slag (BCS) contain impurities of potentially toxic elements (PTEs), such as As, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn that can be released into environment. The present study was conducted with the aim to characterize the solid phase composition of blasted copper slag (BCS) and to investigate the leaching of PTEs from BCS under influence of pH. A wide pH range (1-10) was investigated in order to assess the environmental implications of different management scenarios. Besides amorphous phases, fayalite, magnetite, maghemite, quartz and elemental copper were the main minerals identified by X-ray diffraction (XRD). Field Emission Gun Electron Probe Micro Analysis (FEG-EPMA) results indicated that BCS mainly consisted of Fe, O and Si with minor amounts of S whereas the copper bearing phase was composed of Cu, Pb, and S with small amounts of Si. This indicates that copper in BCS was present not only in metallic phases but also in association with S in the form of sulphides (sulphides of Cu, Cu-Pb, Cu-Pb-Zn). Mapping of selected areas in thin sections with wavelength dispersive spectrometry also confirmed the presence of these sulphide phases which were not detected by XRD. Among the examined PTEs, Cr was found in Fe-O rich phases, while Mo was observed in a glass inclusion. These This might explain the low leachability of these elements in neutral pH conditions. Leaching tests indicated that most of the PTEs showed a low environmental concern in the neutral-alkaline pH range due to the low concentrations in the leachate compared to EU leaching limit value for non-hazardous waste, except As which exceeded this threshold at pH 10. Moreover, in the case of acidification (e.g. as a results of co-disposal with acid waste or as a result of acid rain), special attention should be paid to Cu and Zn which exhibit an important release at pH 3-5. On the other hand, recovery of Cu by acid treatment of the slag could be considered since an extraction with HNO3 1 M during 24 h showed that 39 % of the total Cu content (or 3369 mg/kg) was released from the slag. The feasibility of Cu recovery from the slag should be further investigated. no issn ispartof: pages:155-159 ispartof: Proceedings of the fourth International Slag Valorization Symposium vol:4 pages:155-159 ispartof: Slag Valorization Symposium location:Leuven date:15 Apr - 17 Apr 2015 status: published

From the Middle Ages until the beginning of the 20th century, extensive Zn-Pb mining and smelting was carried out in East-Belgium. By lack of waste treatment techniques and sustainable management practices, metal-bearing slags and unprocessed waste were dumped in huge tailings, which still represent an important source of contamination. A chemical and mineralogical characterization of different types of mining waste originating from the former Pb-Zn mining industry was performed in order to gain a better understanding of the slag properties, with special attention to heavy metal release under varying pH conditions, and to bring this in relation to different management scenarios. ispartof: Waste and Biomass Valorization vol:5 issue:3 pages:355-368 status: published

Copper slag is widely used as abrasive material for removing rust and marine deposits from ships to prepare the surface before painting. Development of shipping industry has raised an environmental concern related to the release of heavy metal from blasted copper slag in Vietnam. This study was conducted to investigate the characteristics of the blasted copper slag (BCS) and potentially contaminated sediment samples collected nearby the shipyard in south of Van Phong bay (south-central of Vietnam). Single extractions (with CaCl2, (NH4)2EDTA, CH3COOH and NaCl) were performed to examine under which conditions As and heavy metals (HMs) may leach from the BCS and sediment. The BCS samples were mainly composed of Fe, Ca, Al and Si (percentage levels). Furthermore, BCS contained significant amounts of Cu, Zn (8416 and 8439 mg/kg respectively) and Mo, Pb, As, Cr (2399, 853, 798 and 566mg/kg respectively). Results from the single extractions suggest that As and HMs in both sediments and BCS showed a low actual mobility and were not easily mobilized by sea water and/or organic complexion. Acidification had a more pronounced effect on As and HM release both in sediments and BCS ispartof: pages:299-308 ispartof: Proceeding of the international conference on “Bien Dong 2012" pages:299-308 ispartof: international conference on “Bien Dong 2012” location:Nha Trang date:12 Sep - 14 Sep 2012 status: published