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...

Spent petroleum catalyst from Korean petrochemical industry contains trace amount of metals such as Ni, V and Mo. Therefore an attempt was made to recover those trace metal using bioleaching process. Different leaching parameters such as Fe(II) concentration, pulp density, pH, temperature and particle size of spent catalyst particle were studied to evaluate their effects on the leaching efficie...

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...

Low-level liquid concentrate wastes including boric acid have been immobilized with paraffin wax using concentrate waste drying system in Korean nuclear power plants since 1995. Small amount of low density polyethylene (LDPE) was added to increase the leaching resistance of the existing paraffin waste form and the influence of LDPE on the leaching behavior of waste form was investigated. It was...

The present study deals with the development of standardized laboratory methods to predict depletion of biocides more accurately under service condition. Laboratory test was conducted with EN 252 standard and non-standard pine as well as spruce specimens to determine leaching of chromium and copper from stakes pressure impregnated with commercial copperand chromium-containing preservative. Two ...

Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 (-) leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 (+) and NO3 (-) release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 (+) and NO3 (-...

This paper discusses the results of Cd, Pb and Ni immobilization using cement. Soil contamination levels were in the range 500 mg/kg to 5,000 rug/kg. and cement ratios were in the range 3% to 18%. The process was highly effective in minimizing the leaching of tested heavy metals. The measured leaching reduction results were as follows: 76% to more than 96% for Pb; 30% to more than 99% for Cd; a...

To evaluate the potential environmental and health implications of leaching of wood preservatives in service under different conditions, there is a need for a predictive model that provides estimates of the rate and extent of leaching over a wide range of exposure conditions. In this paper, we test the hypothesis that preservative component emissions can be modeled on the basis of three easily ...

In present investigation the biological leaching of aluminum by isolated fungi from red mud, the main waste product of the alkaline extraction of Al from bauxite was studied. Biological leaching experiments were carried out using indigenous, date and orange specimen fungi, Aspergillus Niger, Penicillium simplicissimum notatum. Savored Dextrose chloramphenicol Agar (SDA) was used as medium for t...