leaching of molybdenite concentrate with hydrogen peroxide in sulfuric acid solution was investigated to determine the effects of reaction time, reaction temperature, h2o2 concentration, h2so4 concentration, pulp density and rotation speed on molybdenum extraction and molybdenite dissolution kinetics, using the taguchi method. from analysis of variance (anova) for molybdenum extraction, the mos...

A systematic comparison of Cu toxicity thresholds was made between freshly spiked soils and soils in which elevated Cu concentrations have been present for various times. Three uncontaminated soils were spiked and experimentally leached or incubated outdoors for up to 18 months. Additionally, five field-contaminated soils with a 6- to 80-year-old Cu contamination were sampled, and corresponding...

Detailed studies on soil processes commonly involve the use of reconstructed soil columns (e.g. James & Riha, 1989; Liu et al., 1990; Smith et al., 1995). This approach reduces the inherent variability associated with field experiments, allows the simultaneous monitoring of solution and solid phases, and limits the interactive effects from concomitant processes. Sample pretreatment (airdrying, ...

[1] Soil water dynamics and drainage are key abiotic factors controlling losses of atmospherically deposited N in Southern California. In this paper soil N leaching and trace gaseous emissions simulated by the DAYCENT biogeochemical model using its original semi‐dynamic water flow module were compared to that coupled with a finite element transient water flow module (HYDRUS), for two mixed coni...

Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Pae...

Bacterial leaching is the extraction of metals from their ores using microorganisms. The most important player in the bioleaching process is. 4 Bacterial Attachment on Mineral Surfaces 200. 5 Microbial Diversity in Bioleaching Environments 200. Minerals are obtained using a leaching process.greater understanding of the mechanism of bacterial leaching of sulphide minerals. This latter process wh...

Stabilization efficiencies of spinel-based construction ceramics incorporating simulated nickel-laden waste sludge were evaluated and the leaching behavior of products investigated. To simulate the process of immobilization, nickel oxide was mixed alternatively with gamma-alumina, kaolinite, and hematite. These tailoring precursors are commonly used to prepare construction ceramics in the build...

Upon rewetting, lichens lose polyols through leaching. We quantified leaching losses for 21 species under simulated rainfall. Polyol concentrations in these lichens range from 1.0 to 8.8%, with a mean of 2.8%. Leaching losses range up to about 7.5 mg (polyol)/g (lichen dry weight) in a typical rain event. The rate of polyol leaching declines exponentially, becoming negligible within 1 hour of c...