Leaching properties of Pb, Cd, Zn, Cu at pH of 2-6 using different inorganic acids (hydrochloric acid, sulfuric acid, nitric acid) and organic acids (acetic acids, citric acid, malic acid, succinic acid) aiming at polluted sediment at downstream of a non-ferrous metal smelting enterprise is discussed. Results showed that leaching concentrations of 4 metals decreased with increasing pH. Among al...

A preliminary survey of an arsenic contaminated site from an abandoned copper smelting facility and feasibility study of using solidification/stabilization (S/S) process to treat the contaminant waste were undertaken. It was found that the waste, located in the three-flue gas discharge tunnels, contained 2-40% arsenic. The pH of the contaminated waste is extremely low (ranging from 1.8 to 3.6)....

Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine-iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercri...

The modelling of pesticide transport through the soil and estimating its leaching to groundwater is essential for an appropriate environmental risk assessment. Pesticide leaching models commonly used in regulatory processes often lack the capability of providing a comprehensive spatial view, as they are implemented as non-spatial point models or only use a few combinations of representative soi...

In order to better understand the role of coal gangue in potential environmental and ecological risks, the leaching behavior of trace elements from coal gangue has been investigated in an open-cast coal mine, Inner Mongolia, China. Four comparative column leaching experiments were conducted to investigate the impacts of leaching time, pH values and sample amount on the leaching behavior of trac...

Title of Document: EVALUATION OF LEACHING PROTOCOLS FOR THE TESTING OF COAL COMBUSTION BYPRODUCTS Jason Louis Becker, Master of Science, 2010 Directed By: Associate Professor Ahmet Aydilek, Department of Civil and Environmental Engineering Beneficial reuse of coal combustion byproducts requires an evaluation of metal leaching potential. Reuse of high carbon fly ash in highway embankment constru...

The leaching characteristics of fly ash from a cobalt smelter were studied as a function of pH and time using the pH-static leaching test (CEN/TS 14997, pH range 5-12) coupled with mineralogical investigation and speciation-solubility modelling. Two sets of experiments with different equilibration time (48 h and 168 h) were performed. The leaching of metals showed typical U-shaped curves with t...

Bioleaching of spent catalyst using moderate thermophilic chemolithotrophic acidophiles in growth medium without Fe source was investigated with two different pulp densities and three different size fractions. All the experiments were conducted on shake flasks at a temperature of 65 °C. The leaching yield of Ni and Al was found to be promising with very high leaching yield of 92-96% followed by...

A study was conducted to evaluate the leaching potential of unpaved road materials (URM) mixed with lime activated high carbon fly ashes and to evaluate groundwater impacts of barium, boron, copper, and zinc leaching. This objective was met by a combination of batch water leach tests, column leach tests, and computer modeling. The laboratory tests were conducted on soil alone, fly ash alone, an...

salinity of soil and water is the most important agricultural hazard in arid and semi-aridregions. in saline soils, yield production directly influences by soluble salts in the root zone aswell as by shallow water table depth. the first step for reclamation of such soils is reducingsalinity to optimum level by leaching. the objective of this study was to develop a practicalmodel to estimate wat...