Bacterial leaching represents an unusual problem in biochemical engineering, because the substrate for bacterial growth is not supplied directly, but is a product of another reaction, the leaching of mineral particles. In addition, leaching is a heterogeneous reaction dependent on the particle-size distribution in the feed and on the kinetics of particle shrinkage. In this study, these effects ...

Leaching of metals from cement under various environmental conditions was measured to evaluate their environmental safety. A cement product containing clinker, which was produced from cement kiln co-processing of hazardous wastes, was solidified and leaching of metals was characterized using the 8-period test. Concentrations and speciation of metals in cements were determined. Effects of ambien...

Polymeric aluminum ferric sulphate(PAFS) was prepared from high-sulfur bauxite flotation tailings and red mud by roasting, acid leaching polymerization. The effects of temperature, time, liquid-solid ratio on the rate Al3+ Fe3+were investigated. optimal conditions are as follows: temperature 100℃, time 90 min, sulfuric concentration 4.5mol/L 5 mg/L. Infrared spectroscopy X-ray diffraction analy...

Abstract A solid waste sample from acidic leaching of Alluoga sedimentary rocks, SW Sinai, Egypt, was processed for and extraction U Cu respectively. This assayed 200 mg/kg 5 g/kg Cu. The present work aims to obtain free through selective alkaline uranium followed by environmentally safe glycine solution copper the resulted waste. Under studied optimum conditions efficiency attained 93% 96% Ura...

There is a need to develop improved accelerated test methods for evaluating the leaching of wood preservatives from treated wood exposed to precipitation. In this study the effects of rate of rainfall and length of intervals between rainfall events on leaching was evaluated by exposing specimens to varying patterns of simulated rainfall under controlled laboratory conditions. Lumber specimens w...

the effect of boundary conditions on the solution of the inverse problem of identifying the geometry and location of a cavity inside an elastic solid body using displacement measurements obtained from a tension test is investigated. the boundary elements method (bem) coupled with the genetic algorithm (ga) and the conjugate gradient method (cgm) are implemented in this identification problem. a...

Column leach test has been performed to examine the behavior of leaching of sodium, calcium and potassium in landfills. In the column leach apparatus, two different layers of contaminated and uncontaminated soils of different height ratios (ratio of depth of contaminated soil to the depth of uncontaminated soil) are taken. Water is poured from an overhead tank at a particular flowrate to the in...

We investigated the potential role of the three strains of Thiobacillus caldus (KU, BC13, and C-SH12) in arsenopyrite leaching in combination with a moderately thermophilic iron oxidizer, Sulfobacillus thermosulfidooxidans. Pure cultures of T. caldus and S. thermosulfidooxidans were used as well as defined mixed cultures. By measuring released iron, tetrathionate, and sulfur concentrations, we ...

Hydrothermally altered igneous rock and mudstone formed under the sea are often rich in arsenic (As). Therefore, As leaching from these rocks excavated during construction work may affect the surrounding soils and groundwater. High-volume, low-concentration contaminants contained in the waste rock as muck have been a major concern in Japan since the Soil Contamination Countermeasures Law was en...

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...