نتایج جستجو برای: biological leaching
تعداد نتایج: 472925 فیلتر نتایج به سال:
The toxicity of endodontic materials is reviewed. The patient may be exposed by constituents leaching from the unset and set sealer and by accidental overfilling of the root canal. For most patients the exposure is believed to be below the threshold for a toxic effect. Most sealers exhibited a cytotoxic response, especially unset and the responses diminished with time after setting. Unset and n...
in this study, the level of cations and anions of saline soil leaching was investigated in laboratory conditions by using of magnetic water. silty loam soil was poured in 50 cm height and 10 cm diameter pipes while the end of each pipe was closed with a filter paper and a plastic net. leaching was conducted alternatively after passing water through the magnetic field with different intensities....
The effect of mechanical activation on the kinetics of ammoniacal thiosulfate leaching of a refractory oxide gold ore containing 2.8 ppm Au was investigated. The gold extraction of 99.81% was achieved by 16 h leaching of a sample mechanically activated for 60 minutes. The gold extraction observed for a similar reference sample without mechanical activation was only 55%. Studies revealed that le...
Processing of anodic slimes from an Egyptian copper electrorefining plant, exhibiting high contents of copper, lead, tin and silver has been presented. The proposed hydrometallurgical process consists of two leaching stages for extraction of copper with H2SO4 – O2 and silver with thiourea – Fe. Pyrometallurgical treatment of the leaching solid residue for production of Pb-Sn soldering alloy was...
This mini-review is devoted to the analysis of current state relatively rarely used underground bio-mining natural minerals. On basis this analysis, it substantiated that bacterial leaching technology has no alternative for environmentally safe and economically break-even mining ore-bearing rocks off -balance metal-bearing formations are difficult access, or unprofitable traditional methods. It...
Leaching of a low-grade lead and zinc oxide ore was studied by an organic reagent, citric acid. The quadratic mathematical models were developed for the relationship among the influential parameters and lead and zinc recoveries. Leaching rate was strongly affected by the interactive effects of factors. It was also found that the quadratic effects of stirring speed and linear<e...
An experimental study was conducted to determine the effects of the leaching parameters on impurity ion concentrations of the liquid phase in ulexite leaching. Powdered ulexite ore was leached in an aqueous medium with sulfur dioxide. The Taguchi experimental design approach and statistical methods were used to evaluate the effects of the leaching parameters (solid/liquid ratio, temperature...
Processing of gold ores with high sulfide minerals is problematic as they consume cyanide and reduce gold leaching. Optimization of gold leaching and cyanide consumption requires a methodology to estimate the amount of exposed cyanicides, their leaching kinetics, and speciation of cyanide complexes that consume the free cyanide and compete with gold. In this paper, a physico-chemical approach i...
A Comparative Study on Bioleaching Properties of Various Sulfide Minerals Using Acidiphilium cryptum
Bioleaching has been regarded as a green alternative to chemical leaching in metal extraction processes. In this study, the bioleaching properties of indigenous acidophilic bacteria for various sulfide minerals were compared and evaluated terms pH reduction leaching. The primary samples sphalerite (ZnS) (SP), galena (PbS) (GN1 GN2), pyrite (FeS2) (PY), chalcopyrite (CuFeS2) (CCP), an bacterium,...
in order to study the effects of irrigation water salinity and leaching fraction on soil chemical characteristic, grain yield, yield components and sodium and potassium contents in leaves of safflower, an experiment was coducted in a split plot design with four replications in 2009 at roudasht, isfahan. treatments included three irrigation water salinities of q1=3.35, q2=8.77 and q3=11.21 ds/m ...
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