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The comparison of leaching with alkaline bacteria, ammonia, or their combination undoubtedly shows that copper recovery is significantly higher when combined with an increase in Cu extraction yield of 4.42% (48 days, ammonia leaching), or about 20% (30 days, alkaline bacteria leaching) at 29.57% (30 days, combined leaching).
This review describes the historical development and current state of metals leaching and sulfide mineral biooxidation by the minerals industries. During the past 20 years commercial processes employing microorganisms for mineral recovery have progressed from rather uncontrolled copper dump leaching to mineral oxidation and …
Microbiological researchers believe that bacteria play an active role in the process of bacterial leaching, and metallurgists regard microorganisms as a kind of "catalyst," to study the bacteriological principle of bacterial leaching, to understand the physiological and biochemical characteristics of the bacterial species, and to clearly ...
10.4.4.3 Remediation by bioleaching. Bioleaching is a common term used for biomining, in which the microbes are used for metal extraction from low-grade ores. It engages the mobilization of positively charged heavy metal ions from the insoluble ores by biological dissolution processes and bio-oxidation.
Bioleaching process and commercial bioheap leaching plants: (a) schematic representation of the bioheap leaching process, (b) bioleaching plant in Zijinshan copper mine, China (Renman et al. 2006), (c) bioheap leaching plant in Talvivara mining company, Finland (Riekkola-Vanhanen 2010) and (d) bioheap leaching plant in …
Bioleaching of silicon is considered a promising strategy for fly ash resource utilization; however, its efficiency still needs improvement. In this study, a co-culture system with Bacillus subtilis and Cystobasidium sp. (1:1) was constructed by antagonistic and flask leaching experiments, which reached the growth stable phase earlier and maintained it …
The 'direct' mechanism requires the attachment of bacteria to the sulfide surfaces. In the case of thiobacilli, bacteria secrete exopolymer that facilitates attachment of the bacteria to a...
In other words, bioleaching is the commercialization of the ability of certain bacteria and archaea, found in nature, to catalyze the oxidation of sulfide minerals. It is the leaching of sulfide minerals that distinguishes bioleaching from conventional acid leaching wherein only oxidized minerals are leached. An associated process is ...
thermophilic bacteria including Thiobacillus thermophilica, Thermothrix thioparus, Thiobacillus TH1, and Sulfobus acidocaldarius. The heterotrophic organisms listed have not as yet actually been used, but it seems likely that processes will be developed by which In addition to this leaching process performed only by micro-
Bioleaching kinetics. Comparison of Li bioleaching by three various types of organisms (Fig. 1) revealed that the leaching kinetics in systems with yeast R. mucilaginosa was the fastest. Presence ...
The Leaching Process. Bacteria perform the key reaction of regenerating the major ore oxidizer which in most cases is ferric iron as well as further ore oxidation. The reaction is performed at the bacterial cell membrane. In the process, free electrons are generated and used for the reduction of oxygen to water which produces energy in the ...
A paper published in 1967 (Beck, 1967) reported temperatures of 60–80 °C in copper leach dumps and Beck proposed that copper leaching at that temperature could only be by a chemical process because of the lethality of temperatures ≥ 45 °C to A. ferrooxidans. This hypothesis was made without the benefit of knowing about …
The final bioleaching yields for bacterial consortium, A. niger and R. mucilaginosa were 8.8%, 0.2% and 1.1%, respectively. Two-step bioleaching using …
Bioleaching is the dissolution of metal sulfides such as pyrite (FeS 2) and is driven by bacterial and archaeal oxidation of iron (II)-ions and sulfur compounds as well …
Cyclic leaching process employing iron oxidizing bacteria . United States Patent 2829964 . Inventors: Zimmerley, Stuart R. Wilson, Dean G. Prater, John D. Application Number: US54238755A . Publication Date: 04/08/1958 . Filing Date: 10/24/1955 . Export Citation: Click for automatic bibliography generation ...
Because of their more rapid growth rate, the thermophilic bacteria may significantly accelerate the leaching process. Process of microbial ore leaching: Thiobacillus ferrooxidans is the organism that has been extensively studied. Itis a gram-negative rod-shaped bacterium which is 0.5-0.8 μm X 1.0-2.0 μm in size.
Now, miners aim to use bacteria or other newly developed chemicals to extract even more copper from that waste rock in a secondary leaching process. That could enable them to produce copper at ...
The leaching process is easier when it comes for the execution. It is not a harmful process in comparison to the other pyrometallurgical methods. It does not lead to any sorts of gaseous pollutants. Disadvantages of Leaching are as Follows. The residual liquid waste that is generated from the leaching process is highly acidic in nature.
2. Bioleaching Process. Bioleaching—as opposed to traditional (heap) leaching—has become an attractive alternative in recent decades due to its potential in mineral leaching on a laboratory scale and, mainly, due to its industrial applications [].The industrial operation applied to the leaching of copper sulfides considers the formation of …
These processes have been applied to heap and tank leaching, nowadays termed biomining, but increasing concerns about the social acceptance of mining has …
The precipitation of jarosite adversely affects the bio-leaching of copper sulfides in the Sarcheshmeh heap bio-leaching process. The variables of the initial concentration of ferrous iron in the growth medium, pH, and temperature were examined in the laboratory to determine how they affect the precipitation of jarosite in the presence of …
Bacterial leaching process of metal sulfides as an economic method has been significantly developed during recent decades. In fact, microorganisms act as a catalyst to reproduce oxidant, that is, transforming …
The bacterial leaching using cultures G1 and G2 was studied in 500 ml glass bulbs with 200 ml of the PW30 nutrient medium that contained 10% (v/v) of ... The possibility of the recovery of iodine from the raffinate at the end of the leaching process also could be beneficial. IOB-based gold bioleaching is less toxic than traditional cyanide ...
In the present study, the feasibility to use phosphate solubilizing bacteria (PSB) to develop a biological leaching process of rare earth elements (REE) from monazite-bearing ore was determined. To predict the REE leaching capacity of bacteria, the phosphate solubilizing abilities of 10 species of PSB were determined by halo zone …
Kennecott's basic process is a cyclic one using ferric sulphate-sulphuric acid carrying cultures of suitably tolerant bacteria in a sulphide mineral leaching stage which then passes through a regeneration stage within which the bacteria-carrying solution is subject to aeration and recycled to the process.
In particular, the significant increase in solubility that results from reducing Fe 3+ to Fe 2+ suggests that a reductive leaching process is most suitable. A wide range of anaerobic iron-reducing bacteria have been demonstrated to exist in the last few decades, which reduce Fe 3+ to Fe 2+ as part of their respiration. More of these organisms ...
The microbial leaching process is a long-term reaction process, ... (QS) exist in some leaching bacteria and control biofilm development, the role for bioleaching processes is important (Farah et al., 2005; Ruiz et al., 2008; González et al., 2013). The metabolites and the enzymes secreted by different microorganisms can synergistically ...
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WEBKey points. • Leaching of metal sulfides is strongly enhanced by microorganisms. • Biofilm formation and extracellular polymer production influences …
However, the above-mentioned anaerobic physiology of leaching bacteria and their presence in anoxic biotopes support the hypothesis of an anaerobic leaching process. For example, the existence of Acidithiobacillus -like species has been demonstrated in an anoxic reactor designed to clean contaminated groundwater and …
Cell-to-cell communication systems of "quorum sensing" (QS) have been described to be present in some leaching bacteria (Farah et al. 2005; Ruiz et al. 2008; González et al. 2012), but their importance for the whole process becomes obvious only in fragments. A detailed knowledge of the interactions among the microorganisms in …
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