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Showing 1 to 14 of 14 for “"Biooxidation"”.
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Quantification of biomass in a biooxidation system
… enumerate the number of bacteria in a minerals biooxidation system. In this system most of the bacteria are attached to fine particles of ore and therefore cannot be enumerated by direct cell counting. This has hindered attempts to understand the mechanism by which the bacteria assist in the …
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Quantification of biomass in a biooxidation system
… enumerate the number of bacteria in a minerals biooxidation system. In this system most of the bacteria are attached to fine particles of ore and therefore cannot be enumerated by direct cell counting. This has hindered attempts to understand the mechanism by which the bacteria assist in the …
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Biooxidation of a gold bearing arsenopyrite/pyrite concentrate
… of this project have been to characterise the biooxidation of an auriferous pyrite/arsenopyrite flotation concentrate, and to interpret laboratory batch and continuous pilot plant data in the light of the logistic model. Furthermore, the possibility of predicting continuous biooxidation plant …
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Biooxidation and Thiocyanate Leaching of Refractory Gold Ore in One-Step
… refractory ore was developed by combining acidic biooxidation (a mixture of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans) and acidic thiocyanate leaching in one system to avoid neutralization and minimize the complexity of the process. Furthermore, …
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Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate
Bioleaching can be categorized as being either stirred tank type (i.e. bio-oxidation) or irrigation type (i.e. heap/dump bioleaching) yet studies investigating the kinetics of bioleaching systems mostly use empirical data determined from stirred tank type and initial rate experiments in batch …
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A study of chemolithoautotrophic bacterial rhodanese, and its potential contribution to cyanide wastage during cyanidation of biooxidized concentrates
… can be successfully and economically treated by biooxidation prior to cyanidation. However, one of the major drawbacks of the biooxidation process is the excessive consumption of cyanide during the gold dissolution process. The largest proportion of cyanide wastage is attributed to thiocyanate …
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Disruption of microorganisms due to agitation in slurries of fine particles
… in slurries of particles in stirred tanks is the biooxidation process. Mixed cultures of thiobacilli are used in stirred tank reactors for the biooxidation of sulphide minerals. In addition to operating conditions, the efficiency of biotechnological processes is dependent on the growth and …
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An assessment of oxygen availability, iron build-up and the relative significance of free and attached bacteria, as factors affecting bio-oxidation of refractory gold-bearing sulphides at high solids concentrations
… reactors that are commonly used for biooxidation, has confounded the interpretation of the effects of individual factors. Analysis of literature data revealed a link between the sulphide grade of a particular material and the highest solids concentration at which the bacterial …
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Biological and Chemical Oxidation of Sulfidic Minerals at Alkaline pH
… of microorganisms and chemical reagents. Biooxidation is a hydrometallurgical oxidation method which can be a pre-treatment method for gold recovery. Iron- and sulfur-oxidizing microorganisms with varying physiological characteristics liberate sulfide matrices by using reduced sulfur …
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Scale-up and Measurement Enhancements of a BioGenerator Bioreactor
… in ferric sulfate broth using microbial biooxidation stoichiometry and electrochemical amplification processes were achieved. Investigation into the direct in-situ measurement of solution pH and iron ion concentration by spectrophotometric techniques on aqueous ferric ions to reduce costs …
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The development of a mathematical model for the bioextraction of the critical raw material magnesium from mine waste using acidithiobacillus caldus
… as it was produced, indicating that the rate of biooxidation was the rate-limiting step. Negligible iron dissolution was observed. Systematic optimisation of the initial pH and solids loading resulted in optimised conditions of pHi = 1 and 0.75% solids loading (m/v). These conditions achieved …
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Identification of Genes Induced under Anaerobic Benzene-Oxidizing Conditions in Dechloromonas aromatica strain RCB
… anaerobic and microaerophilic conditions. Biooxidation of benzene under aerobic conditions is well-studied. However, oxygen is scarce in contaminated subsurface environments, and after the aerobic breakdown of benzene, oxygen is quickly depleted from the most heavily contaminated regions …
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Chemical and Biological Treatment of Acid Mine Drainage for the Removal of Heavy Metals and Acidity
This dissertation reports the design of a process (patent pending) to remove iron from acid mine drainage (AMD) without the formation of metal hydroxide sludge. The system includes the oxidation of ferrous iron in a packed bed bioreactor, the precipitation of iron within a fluidized bed, the …
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An investigation into the fundamental understanding of an activated sludge bioremediation process and optimisation of thiocyanate and cyanide destruction
… sulphide containing refractory ores using biooxidation as a pre-treatment has become increasingly important due to the depletion of free milling ores. The reaction of CN with reduced sulphur species during the cyanidation process results in the formation of thiocyanate (SCN), often at …