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Ndlovu, Sehliselo. "Bacterial leaching of pyrite single crystals". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401694.
Pełny tekst źródłaDeveci, Haci. "Bacterial leaching of complex zinc/lead sulphides using mesophilic and thermophilic bacteria". Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341175.
Pełny tekst źródłaSeifelnassr, A. A. S. "Bacterial aided percolation leaching of copper sulphide ores". Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234445.
Pełny tekst źródłaGarcia, Íris Gabriela [UNESP]. "Consórcios microbianos associados a ambientes de minas: obtenção, avaliação fisiológica e molecular". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/88026.
Pełny tekst źródłaNa natureza, os sulfetos minerais constituem a principal fonte para extração industrial de metais, como o cobre, o chumbo, o zinco e o níquel. A calcopirita (CuFeS2) é um sulfeto de cobre importante, sendo o mineral de cobre mais abundante na natureza. Dentre os processos utilizados para a extração de metais está a biolixiviação, que consiste no processamento de minérios utilizando-se micro-organismos, e é reconhecida hoje como uma metodologia interessante sob os pontos de vista econômico e ambiental. Neste contexto, este trabalho foi desenvolvido com o objetivo de se obter consórcios oxidantes de ferro e de enxofre capazes de promover a solubilização da calcopirita. Para obtenção dos consórcios, quinze amostras minerais fornecidas pela Companhia Vale S.A. foram enriquecidas em meios de cultivo específicos. Foram obtidos 4 consórcios oxidantes de ferro e 4 oxidantes de enxofre, denominados Dep SOS-4, S3A, SO3, D1. A análise dessas amostras minerais por difração de raios X evidenciou a presença predominante de quartzo (SiO2) nas amostras Dep SOS-4 e S3A e nas amostras D1 e SO3 também foi observado covelita (CuS), pirrotita (FeS), calcopirita (CuFeS2) e enxofre (S0). Os consórcios oxidantes de ferro foram adaptados ao crescimento em calcopirita e submetidos a ensaios de biolixiviação em calcopirita. Agrupamentos dos consórcios também foram realizados, porém sem adaptação prévia à calcopirita. Nos ensaios de biolixiviação, os valores de Eh se elevaram continuamente nos frascos inoculados, estabilizando ao redor de 550 mV, indicando o aumento da relação Fe3+/Fe2+, o que afeta diretamente a solubilização dos metais pela ação oxidante do Fe3+. Mesmo considerando que a calcopirita é um dos sulfetos mais refratários ao ataque oxidante, bacteriano ou químico, a extração de cobre nos ensaios...
In nature, sulphide minerals are the main sources for extraction of some metals for industrial uses, such as copper, lead, zinc and nickel. One of the most important and explored copper sulphide is chalcopyrite, being the most abundant copper mineral in nature. Metals can be extracted using microorganisms, leading the bioleaching to an economic and environmentally sustainable process. In this research, it was developed different iron and sulfur oxidizer consortium to promote chalcopyrite (CuFeS2) solubilization. All consortium were obtained from previous enrichment in a specific culture of 15 ore samples provided by Companhia Vale S.A. Four iron oxidizer and four sulfur oxidizer consortium were prepared, and named Dep SOS-4, S3A, SO3 and D1. X ray diffraction of the Dep SOS-4 and S3A samples showed mainly quartz content (SiO2), whereas the SO3 and D1 samples showed covellite (CuS), pyrrothite (FeS), chalcopyrite (CuFeS2) and sulfur (S0) presence too. The iron oxidizer consortium were adapted to grow with chalcopyrite and then used in shake flasks experiments with chalcopyrite. A mix of consortiums was performed, but without a previous adaptation to the chalcopyrite. The Eh values increased during the bioleaching of the inoculated flasks, stabilizing around 550 mV, which affects metal solubilization due to an increase in the Fe+3/Fe+2 ratio. The iron oxidizer consortium resulted in a better dissolution of the chalcopyrite when compare with the control, sulfur oxidizer consortium and pure strain At. thiooxidans - FG01. However, it was not observed any significant difference between the consortium and At. ferrooxidans - LR in the chalcopyrite dissolution. In the respirometric tests with chalcopyrite as substrate were observed lower consumption of oxygen to the iron oxidizer consortium (Dep SOS -4, S3A, SO3 and D1) in relation to... (Complete abstract click electronic access below)
Garcia, Íris Gabriela. "Consórcios microbianos associados a ambientes de minas : obtenção, avaliação fisiológica e molecular /". Araraquara, 2013. http://hdl.handle.net/11449/88026.
Pełny tekst źródłaBanca: Ana Teresa Lombardi
Banca: Monica Cristina Teixeira
Resumo: Na natureza, os sulfetos minerais constituem a principal fonte para extração industrial de metais, como o cobre, o chumbo, o zinco e o níquel. A calcopirita (CuFeS2) é um sulfeto de cobre importante, sendo o mineral de cobre mais abundante na natureza. Dentre os processos utilizados para a extração de metais está a biolixiviação, que consiste no processamento de minérios utilizando-se micro-organismos, e é reconhecida hoje como uma metodologia interessante sob os pontos de vista econômico e ambiental. Neste contexto, este trabalho foi desenvolvido com o objetivo de se obter consórcios oxidantes de ferro e de enxofre capazes de promover a solubilização da calcopirita. Para obtenção dos consórcios, quinze amostras minerais fornecidas pela Companhia Vale S.A. foram enriquecidas em meios de cultivo específicos. Foram obtidos 4 consórcios oxidantes de ferro e 4 oxidantes de enxofre, denominados Dep SOS-4, S3A, SO3, D1. A análise dessas amostras minerais por difração de raios X evidenciou a presença predominante de quartzo (SiO2) nas amostras Dep SOS-4 e S3A e nas amostras D1 e SO3 também foi observado covelita (CuS), pirrotita (FeS), calcopirita (CuFeS2) e enxofre (S0). Os consórcios oxidantes de ferro foram adaptados ao crescimento em calcopirita e submetidos a ensaios de biolixiviação em calcopirita. Agrupamentos dos consórcios também foram realizados, porém sem adaptação prévia à calcopirita. Nos ensaios de biolixiviação, os valores de Eh se elevaram continuamente nos frascos inoculados, estabilizando ao redor de 550 mV, indicando o aumento da relação Fe3+/Fe2+, o que afeta diretamente a solubilização dos metais pela ação oxidante do Fe3+. Mesmo considerando que a calcopirita é um dos sulfetos mais refratários ao ataque oxidante, bacteriano ou químico, a extração de cobre nos ensaios... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In nature, sulphide minerals are the main sources for extraction of some metals for industrial uses, such as copper, lead, zinc and nickel. One of the most important and explored copper sulphide is chalcopyrite, being the most abundant copper mineral in nature. Metals can be extracted using microorganisms, leading the bioleaching to an economic and environmentally sustainable process. In this research, it was developed different iron and sulfur oxidizer consortium to promote chalcopyrite (CuFeS2) solubilization. All consortium were obtained from previous enrichment in a specific culture of 15 ore samples provided by Companhia Vale S.A. Four iron oxidizer and four sulfur oxidizer consortium were prepared, and named Dep SOS-4, S3A, SO3 and D1. X ray diffraction of the Dep SOS-4 and S3A samples showed mainly quartz content (SiO2), whereas the SO3 and D1 samples showed covellite (CuS), pyrrothite (FeS), chalcopyrite (CuFeS2) and sulfur (S0) presence too. The iron oxidizer consortium were adapted to grow with chalcopyrite and then used in shake flasks experiments with chalcopyrite. A mix of consortiums was performed, but without a previous adaptation to the chalcopyrite. The Eh values increased during the bioleaching of the inoculated flasks, stabilizing around 550 mV, which affects metal solubilization due to an increase in the Fe+3/Fe+2 ratio. The iron oxidizer consortium resulted in a better dissolution of the chalcopyrite when compare with the control, sulfur oxidizer consortium and pure strain At. thiooxidans - FG01. However, it was not observed any significant difference between the consortium and At. ferrooxidans - LR in the chalcopyrite dissolution. In the respirometric tests with chalcopyrite as substrate were observed lower consumption of oxygen to the iron oxidizer consortium (Dep SOS -4, S3A, SO3 and D1) in relation to... (Complete abstract click electronic access below)
Mestre
Coram, Nicolette Joanne. "Molecular characterization of iron-oxidizing Leptospirillum strains from around the world". Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52944.
Pełny tekst źródłaENGLISH ABSTRACT: More than sixteen isolates of iron-oxidizing bacteria belonging to the genus Leptospirillum were included in this study, with the finding that they were clearly divisible into two major groups. Group I leptospirilla had mol% G+C ratios within the range 49-52%, three copies of rrn genes and based on 16S rRNA sequence data, clustered together with the Leptospirillum ferrooxidans type strain (DSM2705or LI5). Group II leptospirilla had mol% G+C ratios of 55-58%, two copies of rrn genes and based on 16S rRNA sequence form a separate cluster. Genome DNA-DNA hybridization experiments indicated that three similarity subgroups were present amongst the leptospirilla tested with two DNA-DNA hybridization similarity subgroups being found within group I. The two groups could also be distinguished based on the sizes of their 16S-23SrRNA gene spacer regions. We propose that the group II leptospirilla should be recognized as a new species with the name Leptospirillum ferriphilum sp. nov. Members of the two species can be rapidly distinguished from each other by amplification of their 16S rRNA genes and carrying out restriction enzyme digests of the products. Several but not all isolates of the group II leptospirilla, but none from group I (L. ferrooxidans) were capable of growth at 45°C. Plasmid DNA was isolated from strain ATCC49879 (L. ferrooxidans). Restriction endonuclease mapping of what appeared to be about 60 kb of plasmid DNA, established that two plasmids of approximately 30.0 kb and 27.0 kb were present. These were named p49879.1 and p49879.2 respectively. Attempts to isolate the plasmids separately were not successful. Partial sequencing of the two plasmids was carried out and sequence analysis of p49879.1 and p49879.2 indicated that the plasmids shared regions of homology. Total plasmid DNA was DIG-labelled and used as a probe in Southern hybridization experiments with genomic DNA from all sixteen original leptospirilla isolates as the target DNA. All leptospirilla belonging to Group I gave a positive signal, little or no homology to Group II leptospirilla was obtained. The region of homology present in all L. ferrooxidans strains was localized to an area on plasmid p49879.2 showing high amino acid identity to a transposase/putative transposase of Methanosarcina acetivorans and plasmid CPl from Deinococcus radiodurans Rl respectively. Whether these regions of homology indicate that complete, functional transposons are present in all L. ferrooxidans isolates still remains to be determined. Preliminary sequence analysis of both plasmids resulted in the identification of regions with amino acid sequence identity to the TnpA and TnpR of the Tn2l-like transposon family, and the mobilization regions of IncQ-like plasmids (particularly that of pTFl from At. ferrooxidans). Another potentially interesting ORF was identified in p49879.2 with high amino acid sequence identity to an ArsR-like protein that belongs to a second atypical family of ArsR transcriptional regulators. Whether this protein is functional in the regulation of arsenic resistance genes has not yet been determined, nor have other arsenic resistance genes been identified. Future work includes further sequence analysis of these plasmids to better understand their contribution to the isolates in which they are found.
AFRIKAANSE OPSOMMING: Meer as sestien isolate van die yster-oksiderende bakterieë, wat aan die genus Leptospirillum behoort, is in die studie ingesluit en die resultate het getoon dat dié groep verder in twee hoof groepe verdeel kan word. Groep I het "n mol% G+C van tussen 49% en 52% gehad, sowel as drie kopieë van die ribosomale gene (rrn). Hiermeesaam het die 16SrRNA volgorde data getoon dat hierdie isolate groepeer saam met Leptospirillum ferrooxidans (DSM2705T en LI5). Groep II leptospirilla het "n mol% G+C van tussen 55% en 58% gehad sowel as twee kopieë van die rrn gene en saam met die 16SrRNA volgorde data het hierdie isolate "n aparte groep gevorm. Genoom DNA-DNA hibridisasie eksperimente het gewys dat daar drie subgroepe onder die Leptospirillum wat getoets was is, met twee naverwante groepe wat onder Groep I val. Daar kan ook tussen die twee hoof groepe onderskei word op grond van die grootte van hul 16S- 23SrRNA intergeniese gebiede. Ons stel dus hier voor dat die Groep II leptospirilla as "n nuwe spesie beskou word naamlik, Leptospirillum ferriphilum sp, nov. Die twee spesies kan maklik onderskei word deur die PKR amplifikasie produk van die 16SrRNA te verteer met restriksie ensieme. Vele, maar nie al van die Groep II isolate kan by 45°C groei nie, terwyl geen van die Groep I leptospirilla (L.ferrooxidans) kan nie. Plasmied DNA was geisoleer uit Leptospirillum ferrooxidans ATCC49879. Aanvanklike analise het gedui op die teenwoordigheid van een 60.0 kb plasmied. Verdere restriksie ensiem kartering het wel getoon dat hierdie, in teen deel, twee plasmiede van ongeveer 30.0 kb en 27.0 kb in grootte is: p49879.1 en p49879.2. Pogings om die twee plasmiede apart te isoleer was onsuksesvol. Totale plasmied DNA is gemerk met die Random primed DNA labelling kit (Roche diagnostics) en gebruik as peiler in Southern klad eksperimente met genoom DNA, van al sestien isolate, as teiken. Alle leptospirilla wat aan Groep I behoort het "n positiewe sein gegee terwyl geen sein teen Groep II DNA opgemerk was nie. Die area wat, tussen die plasmiede en Groep I homologie getoon het, is gelokaliseer tot "n area op plasmied p49879.2 wat hoë amino suur identiteit toon aan "n transposase geen van Methanosarcina acetivorans, en "n voorgestelde transposase geen op plasmied CPI van Deinococcus radiodurans Rl. Dit moet nog vasgestel word of hierdie area van homologie dui op die teenwoordigheid van "n volledige, funksionele transposon in alle L. ferrooxidans isolate. Gedeeltelike DNA volgorde bepalings van beide plasmiede het gelei tot die identifikasie van areas met hoë amino suur volgorde identiteit aan die TnpA en TnpR gene van die Tn21-tipe transposon familie, sowel as aan die mobilisasie gene van IncQsoortige plasmiede (veral die van pTFI uit Acidithiobacillus ferrooxidans). "n Oop lees raam van belang, wat op plasmied p49879.2 geidentifiseer was, het hoë amino suur volgorde identiteit aan "n ArsR-tipe geen getoon wat aan "n tweede atiepiese familie van ArsR transkripsionele reguleerders behoort. Op die stadium is dit nog onbekend of hierdie protein funksioneel is in die regulering van arseen weerstandbiedenheidsgene.
Tasa, Andrus. "Biological leaching of shales : black shale and oil shale /". Tartu : Tartu University Press, 1998. http://bibpurl.oclc.org/web/24619.
Pełny tekst źródłaTogamana, Culwick. "The evaluation of the stability of metalliferrous tailings by chemical and microbiological leaching". Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388592.
Pełny tekst źródłaChapman, J. T. "The batch and continuous bacterial leaching kinetics of a refractory gold-bearing pyrite concentrate". Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/17706.
Pełny tekst źródłaThe recent focus on bacterial leaching as a preoxidation step in the treatment of refractory gold bearing sulphide ores and concentrates, has created the need for kinetic models to adequately describe bacterial leaching reactor performance. This work is a kinetic study of the bacterial leaching of a refractory gold bearing, pyrite concentrate. The study includes the presentation of two mechanistically based, the shrinking particle and propagating pore (Hansford and Drossou, 1986), batch reactor kinetic models. These models are derived for single stage continuous reactor description. In addition, the empirical logistic growth model (Pinches et al., 1987) is presented for both batch and continuous reactor description. The models are correlated with the experimental data. Three narrow size fractions of the pyrite concentrate were subjected to batch and continuous bacterial oxidation, using a Thiobacillus ferrooxidans culture. Time profile data of the pyrite oxidation were obtained for the batch reactor study. Similarly, retention time profile data of pyrite oxidation was obtained for the single stage continuous reactor. The .gold extraction as a function of sulphide oxidation as well as fraction arsenic leached, was established.
Francisco, Junior Wilmo Ernesto [UNESP]. "Estudo da oxidação de covelita (CuS) e molibdenita (MoS2) sintéticas por Acidithiobacillus ferrooxidans". Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/88034.
Pełny tekst źródłaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A lixiviação bacteriana, ou biolixiviação é um processo biotecnológico que se fundamenta na utilização de microorganismos capazes de solubilizar metais pela oxidação de sulfetos metálicos, sendo nos dias atuais, uma das mais importantes alternativas para a extração de metais, sobretudo do ponto de vista ambiental e econômico. Uma das principais espécies utilizada neste processo é o Acidithiobacillus ferrooxidans, uma bactéria aeróbia, mesofílica e acidofílica, que obtém energia pela oxidação de substratos inorgânicos, basicamente o íon ferroso e compostos reduzidos de enxofre. Todavia, a interação dessa espécie com os sulfetos metálicos é um assunto ainda pouco entendido e de muita controvérsia na literatura. Com intuito de melhor entender estas diferenças, o presente trabalho estudou a oxidação da molibdenita (MoS2) e da covelita (CuS) pelo A. ferrooxidans linhagem LR em algumas condições fisiológicas, destacando-se a fonte energética de crescimento (íon ferroso e S0) e a remoção das substâncias exopoliméricas (EPS) para células crescidas em íon ferroso. A cinética de oxidação destes sulfetos também foi avaliada. Tais estudos foram realizados pela técnica de respirometria celular, que permite avaliar rapidamente a oxidação do substrato a partir de medidas de oxigênio consumido pela bactéria. Em todas as condições testadas a covelita apresentou significativa diferença de oxidação pelo A. ferroxidans LR em comparação com a molibdenita. A análise da cinética de oxidação dos sulfetos demonstrou que a molibdenita apresenta uma cinética que segue Michaelis-Menten, o mesmo não acontecendo para a covelita, provavelmente devido a forma com que estes sulfetos reagem ao ataque químico-bacteriano, fato determinado pelas estruturas eletrônicas dos sulfetos minerais.
Bacterial leaching or bioleaching is a biotechnological process that applies microorganisms able to solubilize metals by metallic sulfides oxidation. This process is nowadays one of the most important alternatives for recovering metals, mainly by environmental and economic aspects. One of the most important bacteria employed in this process is Acidithiobacillus ferrooxidans. It is a gram-negative, acidophilic, aerobic and chemoautotrophic bacteria that obtain energy by the oxidation of inorganic substrates like ferrous ion and reduced sulfur compounds, including metal sulfides. Nevertheless, the interaction of this specie with metallic sulfides remains unclear. With the aim to understand these interactions, the present work has studied the covellite (CuS) and molydenite (MoS2) oxidation by A. ferrooxidans strain LR under different physiological conditions such as the source energy for growth (S0 and ferrous ion) and the removal of extracellular polymeric substances (EPS). These studies were performed by respirometric technique tha t allow evaluating very quickly the substrate oxidation by oxygen uptake measures. For all essays realized it was observed that the efficiency of covellite oxidation by A. ferrooxidans LR is much better than molybdenite. On the kinetic oxidation analyses, molybdenite revealed to be according to Michaelis-Menten substrate saturate kinetic. On the other hand, covellite was not in agreement with Michalis-Menten kinetic. This finding is probably associated with the pathway which these minerals sulfide react to chemistry-bacterial attack, what is influenced by electronic structures of mineral sulfides. Regarding essays performed with cells of A. ferrooxidans strain LR grown with different substrates (ferrous ion and sulfur) and to essays which EPS of bacterial cells were removed, the results obtained did not show differences in covellite oxidation.
Sampson, Mark Ian. "Influence of the cell properties of acidophilic bacteria during attachment to mineral sulfides and consumption during the oxidation of ferrous iron". Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297789.
Pełny tekst źródłaEwart, D. Keith. "Studies on a moderately thermophilic mixed culture of bacteria and its application to the biooxidation of gold-bearing minerals". Thesis, King's College London (University of London), 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389882.
Pełny tekst źródłaNorman, Philippa Fernandes. "An Investigation into the bacterial leaching of a gold-bearing pyrite/arsenopyrite ore". Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/21903.
Pełny tekst źródłaThe main aim of this study was to develop an economically viable bacterial leaching process for a gold-containing pyrite/arsenopyrite ore. The effect of various parameters on, and the mechanism of, bacterial leaching were investigated. Initially milled run-of-mine ore was examined. Batch tests and a continuous bacterial leach were carried out. Bacterial leaching was successful and 91-93% gold dissolution was attained in four days. The process was not economically feasible when compared to the standard flotation-roasting process.
Santos, Ana Laura Araújo [UNESP]. "Efeito do potencial de óxido-redução na biolixiviação da calcopirita". Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110371.
Pełny tekst źródłaAs fontes naturais de minérios sulfetados vêm se esgotando rapidamente devido à demanda por metais nas indústrias de bens de produção e de consumo. O cobre é um dos metais de maior interesse econômico. Cerca de 70% deste metal é encontrado na natureza na forma de calcopirita (CuFeS2), contudo é o mineral que possui maiores limitações em sua extração. Dentre os processos de extração têm-se a biolixiviação, que utiliza micro-organismos capazes de promoverem a solubilização de metais pela oxidação de sulfetos metálicos, apresentando vantagens em relação às técnicas já utilizadas, principalmente de cunho econômico e ambiental. Neste contexto, o presente trabalho foi desenvolvido com o objetivo de avaliar a influência do potencial de óxido-redução na solubilização de cobre a partir da calcopirita. Para isso, foram realizados ensaios de oxidação de íons ferrosos na presença e ausência do mineral. A bactéria utilizada nos ensaios foi a Acidithiobacillus ferrooxidans - LR, espécie acidófila mais estudada e mais encontrada em ambientes de mina. A amostra de calcopirita, proveniente da localidade de La Chorrera, na Colômbia, foi analisada por difração de raios-X (DRX) e evidenciou a presença dominante de calcopirita. Os ensaios de oxidação foram realizados em frascos, agitados a 150 rpm, a 30ºC sob diferentes concentrações de íons ferrosos (100, 200 e 300 mmol L-1) em meio T&K. Aos sistemas foram adicionados 2,5% (m/v) de calcopirita e 5% (v/v) do inóculo fresco de A. ferrooxidans. Nas condições abióticas, em todas as concentrações de Fe2+, o potencial redox atingiu, em média, 420 mV (Ag|AgCl|KCl(sat)), e foram os sistemas que apresentaram as maiores porcentagens de recuperação de cobre, sendo elas 73%, 90% e 78%, respectivamente, após 100 dias de ensaio. Contudo, os sistemas que continham bactéria apresentaram uma recuperação ínfima de cobre, chegando a apenas 17%, em um potencial médio...
Natural sources of sulfide ores come depleting rapidly due to the demand for metal goods industries in production and consumption. Copper is a metal of greater economic interest. About 70% of this metal is found in nature in the form of chalcopyrite (CuFeS2), however it is the mineral that present a major limitations in its extraction. One of the extraction processes is bioleaching, which uses microorganisms capable of promoting the solubilization of metals by metal sulfides oxidation and presents advantages over the common techniques used, mainly for economic and environmental nature. In this context, the present work was carrying out to evaluate the influence of the redox potential in the solubilization of copper from chalcopyrite. For this, ferrous ions oxidation tests were conducted in the presence and absence of the mineral. The bacterium used in the tests was Acidithiobacillus ferrooxidans - LR, the acidophilic species most studied and most commonly found in mine environments. A sample of chalcopyrite from La Chorrera, Colombia, was analyzed by X-ray diffraction (XRD) and showed the dominant presence of chalcopyrite. Ferrous ions oxidation tests were carried out in shaken flasks at 150 rpm, at 30 ºC using different concentrations of ferrous ions (100, 200, and 300 mmol L-1) in T&K medium. The systems were supplied with 2,5% (w/v) of chalcopyrite and 5% (v/v) of A. ferrooxidans fresh inoculum. At the abiotic conditions, the redox potential achieved 420 mV (Ag|AgCl|KCl(sat)) in all ferrous ions concentrations. Besides, these systems showed the highest copper recovery concentrations, such 73%, 90% and 78%, respectively, after 100 days of testing. However, the bacterial systems showed a low copper recovery, about 17% in a redox potential of 610 mV (Ag|AgCl|KCl(sat)). The solid residues were evaluated by XRD and showed, at abiotic conditions the formation of elemental sulfur, jarositas and a significant decrease in chalcopyrite’s...
Santos, Ana Laura Araújo. "Efeito do potencial de óxido-redução na biolixiviação da calcopirita /". Araraquara, 2014. http://hdl.handle.net/11449/110371.
Pełny tekst źródłaBanca: Assis Vicente Benedetti
Banca: Paulo Teixeira Lacava
Resumo: As fontes naturais de minérios sulfetados vêm se esgotando rapidamente devido à demanda por metais nas indústrias de bens de produção e de consumo. O cobre é um dos metais de maior interesse econômico. Cerca de 70% deste metal é encontrado na natureza na forma de calcopirita (CuFeS2), contudo é o mineral que possui maiores limitações em sua extração. Dentre os processos de extração têm-se a biolixiviação, que utiliza micro-organismos capazes de promoverem a solubilização de metais pela oxidação de sulfetos metálicos, apresentando vantagens em relação às técnicas já utilizadas, principalmente de cunho econômico e ambiental. Neste contexto, o presente trabalho foi desenvolvido com o objetivo de avaliar a influência do potencial de óxido-redução na solubilização de cobre a partir da calcopirita. Para isso, foram realizados ensaios de oxidação de íons ferrosos na presença e ausência do mineral. A bactéria utilizada nos ensaios foi a Acidithiobacillus ferrooxidans - LR, espécie acidófila mais estudada e mais encontrada em ambientes de mina. A amostra de calcopirita, proveniente da localidade de La Chorrera, na Colômbia, foi analisada por difração de raios-X (DRX) e evidenciou a presença dominante de calcopirita. Os ensaios de oxidação foram realizados em frascos, agitados a 150 rpm, a 30ºC sob diferentes concentrações de íons ferrosos (100, 200 e 300 mmol L-1) em meio T&K. Aos sistemas foram adicionados 2,5% (m/v) de calcopirita e 5% (v/v) do inóculo fresco de A. ferrooxidans. Nas condições abióticas, em todas as concentrações de Fe2+, o potencial redox atingiu, em média, 420 mV (Ag|AgCl|KCl(sat)), e foram os sistemas que apresentaram as maiores porcentagens de recuperação de cobre, sendo elas 73%, 90% e 78%, respectivamente, após 100 dias de ensaio. Contudo, os sistemas que continham bactéria apresentaram uma recuperação ínfima de cobre, chegando a apenas 17%, em um potencial médio...
Abstract: Natural sources of sulfide ores come depleting rapidly due to the demand for metal goods industries in production and consumption. Copper is a metal of greater economic interest. About 70% of this metal is found in nature in the form of chalcopyrite (CuFeS2), however it is the mineral that present a major limitations in its extraction. One of the extraction processes is bioleaching, which uses microorganisms capable of promoting the solubilization of metals by metal sulfides oxidation and presents advantages over the common techniques used, mainly for economic and environmental nature. In this context, the present work was carrying out to evaluate the influence of the redox potential in the solubilization of copper from chalcopyrite. For this, ferrous ions oxidation tests were conducted in the presence and absence of the mineral. The bacterium used in the tests was Acidithiobacillus ferrooxidans - LR, the acidophilic species most studied and most commonly found in mine environments. A sample of chalcopyrite from La Chorrera, Colombia, was analyzed by X-ray diffraction (XRD) and showed the dominant presence of chalcopyrite. Ferrous ions oxidation tests were carried out in shaken flasks at 150 rpm, at 30 ºC using different concentrations of ferrous ions (100, 200, and 300 mmol L-1) in T&K medium. The systems were supplied with 2,5% (w/v) of chalcopyrite and 5% (v/v) of A. ferrooxidans fresh inoculum. At the abiotic conditions, the redox potential achieved 420 mV (Ag|AgCl|KCl(sat)) in all ferrous ions concentrations. Besides, these systems showed the highest copper recovery concentrations, such 73%, 90% and 78%, respectively, after 100 days of testing. However, the bacterial systems showed a low copper recovery, about 17% in a redox potential of 610 mV (Ag|AgCl|KCl(sat)). The solid residues were evaluated by XRD and showed, at abiotic conditions the formation of elemental sulfur, jarositas and a significant decrease in chalcopyrite's...
Mestre
Mikkelsen, Deirdre. "The development and use of molecular phylogenetic and microscopy methods to study thermophilic bioleaching cultures /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18580.pdf.
Pełny tekst źródłaFrancisco, Junior Wilmo Ernesto. "Estudo da oxidação de covelita (CuS) e molibdenita (MoS2) sintéticas por Acidithiobacillus ferrooxidans /". Araraquara : [s.n.], 2006. http://hdl.handle.net/11449/88034.
Pełny tekst źródłaAbstract: Bacterial leaching or bioleaching is a biotechnological process that applies microorganisms able to solubilize metals by metallic sulfides oxidation. This process is nowadays one of the most important alternatives for recovering metals, mainly by environmental and economic aspects. One of the most important bacteria employed in this process is Acidithiobacillus ferrooxidans. It is a gram-negative, acidophilic, aerobic and chemoautotrophic bacteria that obtain energy by the oxidation of inorganic substrates like ferrous ion and reduced sulfur compounds, including metal sulfides. Nevertheless, the interaction of this specie with metallic sulfides remains unclear. With the aim to understand these interactions, the present work has studied the covellite (CuS) and molydenite (MoS2) oxidation by A. ferrooxidans strain LR under different physiological conditions such as the source energy for growth (S0 and ferrous ion) and the removal of extracellular polymeric substances (EPS). These studies were performed by respirometric technique tha t allow evaluating very quickly the substrate oxidation by oxygen uptake measures. For all essays realized it was observed that the efficiency of covellite oxidation by A. ferrooxidans LR is much better than molybdenite. On the kinetic oxidation analyses, molybdenite revealed to be according to Michaelis-Menten substrate saturate kinetic. On the other hand, covellite was not in agreement with Michalis-Menten kinetic. This finding is probably associated with the pathway which these minerals sulfide react to chemistry-bacterial attack, what is influenced by electronic structures of mineral sulfides. Regarding essays performed with cells of A. ferrooxidans strain LR grown with different substrates (ferrous ion and sulfur) and to essays which EPS of bacterial cells were removed, the results obtained did not show differences in covellite oxidation.
Orientador: Oswaldo Garcia Júnior
Coorientador: Denise Bevilaqua
Banca: Assis Vicente Benedetti
Banca: Fernanda de Castro Reis
Mestre
Chukwuchendo, Emmanuel Chukwunonso. "Bio-oxidation of ferrous iron at low temperature conditions in a packed bed column bioreactors". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2545.
Pełny tekst źródłaThe oxidation of microbial ferrous iron is an important sub-process in the bioleaching process. Several studies focussing on microbial ferrous iron oxidation have been investigated and reported in various studies. These studies were carried out using stirred tank bioreactors and shake flasks at optimum conditions. However, these studies could not describe the context of heap bioleach system. Packed column system may describe heap bioleaching, and most studies on microbial ferrous iron oxidation were performed under flooded conditions, which do not represent solution flow dynamics in a heap situation. Biooxidation of ferrous iron oxidation kinetics of Acidiobacillus ferrooxidans was studied in a packed-bed bioreactor to investigate the kinetics in a system that mimics the solution flow dynamic of a heap bioleach operation at low-temperature conditions. This was done in a batch mode operation, with glass marble (15 mm) as reactor packing. The pH of the bioreactor was maintained at pH 1.35 ± 0.05 and aeration at 500 ml/min. Unstructured models known as Monod and Hansford were used to describe the experimental data in determining the kinetics of bio-oxidation.
Jiang, Shuang. "Bacterial leaching from dairy shed effluent applied to a fine sandy loam under flood and spray irrigations". Lincoln University, 2008. http://hdl.handle.net/10182/668.
Pełny tekst źródłaHarahuc, Lesia. "Control of iron and sulfur oxidation activities of Thiobacillus ferrooxidans and bacterial leaching of metals from sulfide ores". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0027/NQ51648.pdf.
Pełny tekst źródłaMabusela, Bongolwethu Professor. "The effect of initial pH on surface properties of ferric ion precipitates formed during microbial oxidation of ferrous ion by Leptospirillum ferriphilum in a CSTR". Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2553.
Pełny tekst źródłaWhile bioleaching is a proven technology for the efficient recovery of base metals from sulphide minerals, its sustenance is dependent on the continuous availability of ferric ion, Fe3+, in soluble form, in the bioleach liquor. However, the solubility of ferric ion is low at higher pH that it tends to precipitate, resulting in the formation of ferric ion precipitates. The formation of ferric ion precipitates in bio-hydrometallurgy decreases the leaching efficiency by trapping the leached metals in solution through an adsorption mechanism which is not well understood. Although the surface properties of the precipitate could be linked to its metal adsorption properties, there has not been a detailed study that gives any indication or explanation of the adsorption mechanism. Therefore, the aim of this study was to investigate the effect of initial pH on the surface properties of ferric ion precipitate and relate this to the adsorption characteristics of the precipitate for desired metals. Biooxidation experiments catalysed by Leptospirillum ferriphilum were conducted in a CSTR with a working volume of 1L. The biooxidation experiments were conducted at pH values of 1.3, 1.5, 1.7, 1.9 and 2.2 at a constant temperature of 35 0C for 14 days. The recovered precipitates were characterized by X-ray diffraction, elemental analyses, SEM, particle size distribution (PSD) and zeta potential. Zeta potential measurements were conducted to investigate what role initial pH plays in modifying the precipitate surface charge and what role the surface charge of each precipitate plays in the nature of adsorption of copper ions onto the precipitate surface. The amount of copper adsorbed onto the precipitate was quantified by the magnitude of the change in surface charge after adsorption experiments. Quantification results showed that the amount of ferric ions precipitates formed increased from 4.31g to 13.26g with an increase in initial pH (from 1.3 to 2.2). The results also showed that significant precipitation of ferric ion occurred during the exponential phase while insignificant precipitation was observed during the stationary phase.
Chan, Lau Chi. "Bioleaching of heavy metals from anaerobically digested sewage sludge using isolated indigenous iron- and sulphur-oxidizing bacteria". HKBU Institutional Repository, 2001. http://repository.hkbu.edu.hk/etd_ra/279.
Pełny tekst źródłaShashikala, A. R. "Role Of Interfacial Phenomena In Bioprocessing Of Minerals Using Bacillus Polymyxa". Thesis, Indian Institute of Science, 2001. https://etd.iisc.ac.in/handle/2005/246.
Pełny tekst źródłaShashikala, A. R. "Role Of Interfacial Phenomena In Bioprocessing Of Minerals Using Bacillus Polymyxa". Thesis, Indian Institute of Science, 2001. http://hdl.handle.net/2005/246.
Pełny tekst źródłaGu, Xiangyang. "Improving heavy metal bioleaching efficiency through microbiological control of inhibitory substances in anaerobically digested sludge". HKBU Institutional Repository, 2003. http://repository.hkbu.edu.hk/etd_ra/504.
Pełny tekst źródłaChandraprabha, M. N. "Studies On Bio-Oxidation A Refractory Gold Containing Sulphidic Concentrate With Respect To Optimization And Modeling". Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/188.
Pełny tekst źródłaChandraprabha, M. N. "Studies On Bio-Oxidation A Refractory Gold Containing Sulphidic Concentrate With Respect To Optimization And Modeling". Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/188.
Pełny tekst źródłaKotze, Andries Albertus. "Analysis of arsenic resistance in the biomining bacterium, Acidithiobacillus caldus". Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/17374.
Pełny tekst źródłaENGLISH ABSTRACT: In this study the chromosomal arsenic resistance (ars) genes shown to be present in all Acidithiobacillus. caldus isolates were cloned and sequenced from At. caldus #6. Ten open reading frames (ORFs) were identified on a clone conferring arsenic resistance, with three homologs to arsenic genes, arsC (arsenate reductase), arsR (regulator) and arsB (arsenite export). This ars operon is divergent, with the arsRC and arsB genes transcribed in opposite directions. Analysis of the putative amino acid sequences of these arsRC and arsB genes revealed that they are the most closely related to the ars genes of Acidithiobacillus ferrooxidans. These ars genes were functional when transformed into an Escherichia coli ars deletion mutant ACSH50Iq, and conferred increased levels of resistance to arsenate and arsenite. ArsC was required for resistance to arsenate, but not for resistance to arsenite. None of the other ORFs enhanced arsenic resistance in E. coli. A transposon located arsenic resistance system (TnAtcArs) has been described for highly arsenic resistant strains of the moderately thermophilic, sulfur-oxidizing, biomining bacterium At .caldus #6. In the latter study it was shown that TnAtcArs confers higher levels of resistance to arsenate and arsenite than the chromosomal operon. TnAtcArs was conjugated into a weakly ars resistant At. caldus strain (C-SH12) and resulted in greatly increased arsenite resistance. RT-PCR analysis revealed that arsR and arsC are co-transcribed. Despite ORF1 (cadmium inducible-like protein) and ORF5 (putative integrase for prophage CP-933R) not being involved in resistance to arsenic, ORF1 was co-transcribed with arsRC and ORF5 with arsB. Using arsR-lacZ and arsB-lacZ fusions it was shown that the chromosomal ArsR-like regulator of At. caldus acts as a repressor of the arsR and arsB promoter expression. Induction of gene expression took place when either arsenate or arsenite was added. The chromosomal located ArsR was also able to repress TnAtcArs, but the transposon-located ArsR was unable to regulate the chromosomal system.
AFRIKAANSE OPSOMMING: In hierdie studie is die chromosomale arseen weerstandbiedendheidsgene (ars gene), teenwoordig in alle Acidithiobacillus caldus isolate, gekloon en die DNA volgorde daarvan vanaf At. caldus #6 bepaal. Tien oopleesrame (ORFs) is geïdentifiseer op ‘n kloon wat arseen weerstandbiedend is, met drie homoloog aan ars gene, nl. arsC (arsenaat reduktase), arsR (reguleerder) en arsB (membraan-geleë pomp wat arseniet uitpomp). Die ars operon is gerangskik met die arsRC en arsB gene wat in teenoorgestelde rigtings getranskribeer word. Analise van die afgeleide aminosuurvolgorde van dié ars gene het getoon hulle is naverwant aan die ars gene van Acidithiobacillus ferrooxidans. Die ars gene was funksioneel na transformasie na ‘n E. coli ars mutant (ACSH50Iq), en het ‘n hoër vlak van weerstand teen arsenaat en arseniet gebied. ArsC was nodig vir weerstand teen arsenaat, maar nie vir weerstand teen arseniet nie. Geen van die ander ORFs het arseen weerstandbiedendheid in E. coli bevorder nie. Voorheen is ‘n ars operon, geleë op ‘n transposon (TnAtcArs), in ‘n hoogs arseen-weerstandbiedende stam van die middelmatige termofiliese, swawel-oksiderende, bio-ontgunning (“biomining”) bakterie Acidithiobacillus caldus #6 beskryf. In laasgenoemde studie is gevind dat TnAtcArs hoër vlakke van weerstand bied teen arsenaat en arseniet as die chromosomale operon. TnAtcArs is na ‘n lae arseen-weerstandbiedende At. caldus stam (C-SH12) gekonjugeer. Die resultaat was ‘n groot verhoging in arseen weerstandbiedendheid. RT-PCR analise het onthul dat arsR en arsC saam getranskribeer word. Benewens die feit dat ORF1 (kadmium induseerbare protein) en ORF5 (afgeleide integrase vir profaag CP-933R) nie betrokke is in weerstand teen arseniet and arsenaat nie, is ORF1 saam met arsRC getranskribeer en ORF5 saam met arsB. Deur gebruik te maak van die fusie-gene arsR-lacZ en arsB-lacZ is bewys dat die chromosomale ArsR reguleerder van At. caldus as ‘n inhibeerder van die arsR en arsB promoter uitdrukking funksioneer. Indusering van geen uitdrukking vind plaas wanneer arseniet of arsenaat bygevoeg word. Die chromosomaal-geleë ArsR is ook in staat om TnAtcArs te inhibeer, terwyl die transposon geleë ArsR nie daartoe in staat is om die chromosomale ars sisteem te reguleer nie.
Goldschmidt, Gunther Karl. "Cloning, Sequencing and Partial Characterization of the Accessory Gene Region of Plasmid pTC-F14 isolated from the Biomining Bacterium Acidithiobacillus caldus f". Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1588.
Pełny tekst źródłaPlasmid pTC-F14 is a 14.2kb promiscuous, broad-host range IncQ-like mobilizable plasmid isolated from Acidithiobacillus caldus f. At. caldus is a member of a consortium of bacteria (along with Acidithiobacillus ferrooxidans and Leptospirilum ferrooxidans) that is used industrially for decomposing metal sulphide ores and concentrates at temperatures of 40ºC or below which is now a well-established industrial process to recover metals from certain copper, uranium and gold-bearing minerals or mineral concentrates. These biomining microbes are usually obligately acidophilic, autotrophic, usually aerobic iron- or sulphur-oxidizing chemolithotrophic bacteria. Their remarkable physiology allows them to inhabit an ecological niche that is largely inorganic and differs from those environments populated by the more commonly studied non-acidophilic heterotrophic bacteria. At. caldus, is a moderately thermophilic (45 to 50ºC), highly acidophilic (pH1.5 to 2.5) sulphur-oxidizing bacterium, and its role as one of the major players in the industrial decomposition of metal sulphide ores has become evident in recent years. At. caldus f from which pTC-F14 was isolated was found to be one of two dominant organisms in a bacterial consortium undergoing pilot-scale testing for the commercial extraction of nickel from ores.
Türe, Didem Beyhan Mehmet. "Kirlenmiş sedimentlerin biyoliç yöntemi ile iyileştirilmesi /". Isparta : SDÜ Fen Bilimleri Enstitüsü, 2008. http://tez.sdu.edu.tr/Tezler/TF01219.pdf.
Pełny tekst źródłaNicolau, Paula Bacelar V. C. "Novel iron-oxidising acidophilic heterotrophic bacteria from mineral leaching environments". Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321390.
Pełny tekst źródłaBlandón, Nury Alexandra Muñoz [UNESP]. "Recuperação de níquel e outros metais a partir de diferentes fontes (rejeitos minerais de processo industrial e pentlandita '(Ni,Fe)IND. 9' 'S IND. 8' ) mediante lixiviação ácida e bacteriana". Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/100745.
Pełny tekst źródłaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Uma possibilidade para a recuperação de metais a partir de minerais com baixos teores ou de rejeitos industriais é a utilização da lixiviação com micro-organismos. A biolixiviação é o processo de oxidação bacteriana de sulfetos metálicos contendo metais de valor (por exemplo, níquel, cobre ou zinco), os quais são liberados para a solução, seguida da recuperação por técnicas metalúrgicas convencionais. Estudos de biolixiviação de concentrados de sulfetos minerais em tanques agitados e, sobretudo em pilhas, têm sido desenvolvidos em escala piloto e comercial. Entretanto, poucos trabalhos têm sido realizados sobre o aproveitamento de rejeitos minerais de processos convencionais, tais como flotação ou fusão em forno “flash”, por rotas biotecnológicas. O objetivo deste trabalho foi recuperar níquel e cobre de rejeitos industriais, provenientes de processo de flotação e de fusão, utilizando bactérias, especialmente da espécie Acidithiobacillus ferrooxidans ou pelo uso de soluções ácidas, em escala de laboratório. Também foram realizados experimentos de biolixiviação de um sulfeto de níquel (pentlandita) para avaliar o processo de solubilização do metal. Conjuntamente, outros experimentos foram realizados com a finalidade de se obter novas linhagens isoladas a partir destes rejeitos minerais. Suas diferenças fisiológicas foram avaliadas. A partir dos experimentos com os rejeitos encontrou-se que com a escória foi possível obter 13% de níquel e 8 % de cobre em solução após 14 dias de lixiviação biológica. Com soluções ácidas, em pH 0,5 e 1,0, as recuperações foram de 56% de níquel e 24% de cobre em pH 0,5 enquanto que em pH 1,0 as concentrações foram de 21% e 12% de niquele e cobre, respectivamente. Para a recuperação de níquel e cobre deste rejeito sugere-se a lixiviação ácida e não bacteriana. Com a lama as porcentagens...
Bacterial leaching is a feasible to recover metals from minerals with low grade or from mine wastes using microorganisms. The bioleaching process is the bacterial oxidation of valuables metals bearing sulphide minerals (e.g. nickel, copper or zinc), which are released to the solution, followed by conventional recovered by metallurgical techniques. Studies on bioleaching of sulphide minerals concentrates in stirred tanks and, particularly, in heaps, have been developed on pilot and commercial scales. However, few studies have been undertaken on using of mineral wastes from conventional processes such as flotation or flashing smelting through biotechnological routes. This work aims at recovering nickel and copper from industrial wastes such as flotation tailings and slag using bacteria, especially Acidithiobacillus ferrooxidans species, or using acid solutions at laboratory scale. Experiments were also accomplished for nickel sulfide bioleaching to evaluate the metal dissolution process, for comparison purpose. Other experiments were also carried out to obtain new strains isolated from mineral waste to study the physiological differences between them. After 14 days of bioleaching of slag it was possible to extract 13% of nickel and 8% of copper in solution while with acid solutions the extractions were 56% of nickel and 24% of copper at pH 0.5 and 21% and 12% at pH 1.0, respectively. For the metals solubilization from the slag it is suggested the acid leaching instead of bioleaching. With the flotation tailings the recoveries of nickel and copper were 23% e 16% at pH 0.5 or 1.0 while after 14 days with bioleaching the concentrations in solution were 46 % and 17% for nickel and copper. These results show that the flotation tailings can be treated with biological leaching for a higher recovery of metals. The studies of nickel sulfide bioleaching with different bacterial species reached only... (Complete abstract click electronic access below)
Yahya, Abidah. "Physiological and phylogenetic studies of some novel acidophilic mineral-oxidising bacteria". Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322564.
Pełny tekst źródłaBlandón, Nury Alexandra Muñoz. "Recuperação de níquel e outros metais a partir de diferentes fontes (rejeitos minerais de processo industrial e pentlandita '(Ni,Fe)IND. 9' 'S IND. 8' ) mediante lixiviação ácida e bacteriana /". Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/100745.
Pełny tekst źródłaAbstract: Bacterial leaching is a feasible to recover metals from minerals with low grade or from mine wastes using microorganisms. The bioleaching process is the bacterial oxidation of valuables metals bearing sulphide minerals (e.g. nickel, copper or zinc), which are released to the solution, followed by conventional recovered by metallurgical techniques. Studies on bioleaching of sulphide minerals concentrates in stirred tanks and, particularly, in heaps, have been developed on pilot and commercial scales. However, few studies have been undertaken on using of mineral wastes from conventional processes such as flotation or flashing smelting through biotechnological routes. This work aims at recovering nickel and copper from industrial wastes such as flotation tailings and slag using bacteria, especially Acidithiobacillus ferrooxidans species, or using acid solutions at laboratory scale. Experiments were also accomplished for nickel sulfide bioleaching to evaluate the metal dissolution process, for comparison purpose. Other experiments were also carried out to obtain new strains isolated from mineral waste to study the physiological differences between them. After 14 days of bioleaching of slag it was possible to extract 13% of nickel and 8% of copper in solution while with acid solutions the extractions were 56% of nickel and 24% of copper at pH 0.5 and 21% and 12% at pH 1.0, respectively. For the metals solubilization from the slag it is suggested the acid leaching instead of bioleaching. With the flotation tailings the recoveries of nickel and copper were 23% e 16% at pH 0.5 or 1.0 while after 14 days with bioleaching the concentrations in solution were 46 % and 17% for nickel and copper. These results show that the flotation tailings can be treated with biological leaching for a higher recovery of metals. The studies of nickel sulfide bioleaching with different bacterial species reached only... (Complete abstract click electronic access below)
Orientador: Oswaldo Garcia Júnior
Coorientador: Denise Bevilaqua
Banca: Maria Lucia Gosales da Costa Araújo
Banca: Ana Teresa Lombardi
Banca: Wilson Cervi da Costa
Banca: Luis Gonzaga Santos Sobral
Doutor
Janosch, Claudia [Verfasser], Wolfgang [Akademischer Betreuer] Sand i Bettina [Akademischer Betreuer] Siebers. "Sulfur oxidation in moderately thermophilic leaching bacteria / Claudia Janosch. Gutachter: Bettina Siebers. Betreuer: Wolfgang Sand". Duisburg, 2013. http://d-nb.info/1042934614/34.
Pełny tekst źródłaKhalfet, Ridha. "Étude d'une colonne à bulles à solide suspendu destinée à la biolixiviation de matières premières minérales : application à la biolixiviation de minerai de pyrite". Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL127N.
Pełny tekst źródłaAndersson, Stefan. "Influence of liming substances and temperature on microbial activity and leaching of soil organic matter in coniferous forest ecosystems /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5850-1.pdf.
Pełny tekst źródłaHaddadin, Jamal. "Études microbiologiques et cinétiques de la lixiviation bactérienne en réacteurs : effet de différents paramètres physico-chimiques, développement d'un procédé en réacteurs air-lift et lit-fluidisé et application à l'extraction de l'antimoine". Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL063N.
Pełny tekst źródłaFlorian, Bianca [Verfasser], Wolfgang [Akademischer Betreuer] Sand i Hans-Curt [Akademischer Betreuer] Flemming. "Investigation of initial attachment and biofilm formation of mesophilic leaching bacteria in pure and mixed cultures and their efficiency of pyrite dissolution / Bianca Michaela Florian. Gutachter: Hans-Curt Flemming. Betreuer: Wolfgang Sand". Duisburg, 2012. http://d-nb.info/1023643790/34.
Pełny tekst źródłaFarias, Christyan Paiva. "Fungos promotores do crescimento vegetal e da fitorremediação de metais pesados em combinação com biochar". Universidade Federal de Uberlândia, 2018. http://dx.doi.org/10.14393/ufu.di.2018.713.
Pełny tekst źródłaThe search for sustainable measures to improve and meet the demand for food that population growth requires, combined with the scarcity of productive land, in addition to the excessive accumulation of metals in the environment due to activities such as mining and application of soil fertilizers, were the two problems that motivated the present study. The use of fungi plant growth promoters: Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum and Trichoderma asperella can both influence on increasing productivity as the phytoremediation of heavy metals in the soil. These facts are explained by the capacity of the fungal Consortium to synthesize and induce plants to produce phytohormone targeted for the better development of the roots of the host. The further development of roots can stimulate phytoextraction of metals from the soil and give plants tolerance to contamination. In order to evaluate the influence of fungi on the development of plants, were done seed treatments of soybeans and corn and application in aerial part of the culture of sugar cane. To analyze the influence of these organisms in the process of phytoremediation of Cu, Zn and Mn in soil columns cultivated with Jacaranda mimosifolia D. Don, fungi were inoculated in soil and aerial part of plants. All treatments had 6 reptitions and their averages were subjected to analysis of variance and average test at 5% probability. The fungal consortium has conditioned the growth of roots of soybeans and corn, mycorrhizal colonization increased in soybeans and sugar cane. In jacarandá, fungi have improved the development of roots and shoots, greater accumulation of Mn and Zn in plant, best of Mn and Zn translocation from roots to shoots, in addition to decrease physiological stress. In addition, the joint application of fungus and biochar in seedlings provides protection to photosynthetic activity and reduces the risk of environmental contamination by metals by decreasing the amount of Cu, Mn and Zn leached. The biochar was acquired through the slow pyrolysis of the eucalyptus wood processing residue and applied superficially to the soil. With that, this study showed that fungi used present potential to contribute to the increased productivity of commercial crops and contribute to the improvement in the remediation of soils contaminated with metal ions.
Dissertação (Mestrado)
Marais, Caroline. "Formation de concrétions calcomagnésiennes par polarisation cathodique associée à la biocalcification et à l’utilisation de matériaux recyclés pour la protection côtière". Electronic Thesis or Diss., La Rochelle, 2023. http://www.theses.fr/2023LAROS020.
Pełny tekst źródłaThe objective of this study is to develop a low environmental impact solution for the consolidation of partially submerged coastal areas. This solution, the formation of a limestone concretion based on seawater electolysis, relies on two main aspects: firstly, the efficient use of local resources through the valorization of inert construction waste (recycled aggregates (RA)); and secondly, the biomineralization process involving the hydration of CO2 by the enzyme carbonic anhydrase (CA) found in marine bacteria sampled from the Port of La Rochelle. Three major axes were studied to optimize the precipitation of a binder within the limeston concretion composed of CaCO3 and Mg(OH)2 (the calcareous deposit): the effect of RA dissolution in seawater, the application of cathodic polarization via seawater flow, and the study of CaCO3 bio-precipitation by CO2 capture (the role of CA) by marine strains. Seawater flow allowed the formation of a 200 cm3 agglomerate in 60 days at -500µA/cm², resulting in a growth rate of 3 cm3/day. A 10% increase in compactness was observed when the grid was buried (within the RA) either submerged or emerged. Seawater flow and the presence of RA favored the precipitation of CaCO3, particularly in the form of calcite, leading to an Mg(OH)2/CaCO3 ratio less than or equal to 1, whether under continuous or cyclic polarization. The excessive release of calcium and sulfate ions into solution due to the dissolution of the cementitious matrix within the RA could explain the increase in CaCO3. All strains bio-precipitated CaCO3 in their optimal medium and in the presence of natural seawater. Their production drastically decreased at 3% CO2 (atmospheric CO2 = 0.4%) and in the presence of leachate from recycled aggregates. At 3% CO2, the pH of the medium increased in the presence of the strains, which could indicate the activity of CA
Simate, Geoffrey Simate. "Bacterial leaching of nickel literites using chemolithotrophic microorganisms". Thesis, 2009. http://hdl.handle.net/10539/7098.
Pełny tekst źródłaBolorunduro, Samuel Adewale. "Kinetics of leaching of chalcocite in acid ferric sulfate media : chemical and bacterial leaching". Thesis, 1999. http://hdl.handle.net/2429/9400.
Pełny tekst źródłaTlotleng, Nonhlanhla. "Evaluation of atomic force microscopy techniques for imaging and studying surface characteristics of bacterial systems involved in bioleaching". Thesis, 2009. http://hdl.handle.net/10210/2457.
Pełny tekst źródłaAtomic force microscopy (AFM) has been an integral tool in bacterial studies for resolving surface structures. Novel applications of this instrument in research require the development of sample preparation techniques and improvement of existing ones. Careful selection of the scanning parameters is particularly crucial when exploring the full potential of the AFM. The objective of this study was to design sample preparation methods for AFM imaging bioleaching bacteria and optimise the scanning parameters (deflection setpoint, feedback loop and the scan rate) for contact mode (CM) imaging in air. The method should be simple, fast and cost effective. The strategy used in this study of (i) evaluation of support substrates for bacterial attachment, (ii) investigation of the effect of pH and centrifugation on cell samples during imaging. Centrifuged and noncentrifuged cell samples suspended in either deionised water (pH 7) or acidified water (pH 1.5) were tested for imaging. Mica and glass cover slips were used as potential substrates for attachment. Cells were attached to substrates for imaging by simple adsorption (‘air-drying’ method). To optimise the scanning parameters, the effect of different values of the scan rate, deflection setpoint and the feedback gains on the quality of AFM imaging was investigated. Optimisation of these parameters was found to be instrumental when imaging weakly adsorbed samples prepared by simple adsorption and ‘soft’ samples such as bacterial cells. The results obtained from these experiments were used during preparation of iron- oxidising leaching bacteria for AFM imaging. The surface morphology of iron-grown bacterial samples was investigated with contact mode AFM in air. Reproducible results obtained in each scan shown by the stability of morphological characteristics of bacterial samples indicate that (i) mica can be used successfully as a substrate for attaching cells, (ii) centrifuged bacterial samples can be easily imaged (iii) scanning with scan rate values of <0.5Hz, deflection setpoint of between 0.2-0.5V and feedback values of < 5.000V improve the image quality and can prevent deformation of the bacterial cells by the tip. Non-centrifuged samples could not be imaged, indicating that bacterial cells need to be separated from growth residues as a prerequisite for successful AFM imaging.
Lizama, Hector M. "Bacterial leaching study of a complex Cu-Zn sulfide ore". 1989. http://hdl.handle.net/1993/16910.
Pełny tekst źródła"The low potential bioleaching of chalcopyrite with ferroplasma JTC3". Thesis, 2009. http://hdl.handle.net/10210/2441.
Pełny tekst źródłaThe leaching of chalcopyrite (CuFeS2) concentrate in a ferrous iron promoted aerobic/anaerobic controlled low potential sulphate system was investigated by using the duel metabolic (aerobic ferrous iron oxidation and anaerobic ferric iron reduction) capabilities of Ferroplasma JTC 3. The experimental work conducted in this study was divided in three sections. The first section focussed on the identification and phylogenetic classification of Ferroplasma JTC 3, first identified amongst a mixed microbial population in a 55 oC pyrite concentrate-fed bioreactor operated at Johannesburg Technology Centre (BHP Billiton, JTC). Based on the 16S rDNA sequence and the phylogenetic analysis, Ferroplasma JTC 3 represents a new species member under the genus of Ferroplasma. The optimal growth temperature of Ferroplasma JTC 3 was determined at approximately 53 oC (moderate thermophile). The second section of this study focussed on the isolation, basic metabolism and growth conditions of Ferroplasma JTC 3, specifically directed towards the chalcopyrite leaching related experimental work. An important aspect of this study was to compare low potential chalcopyrite leaching (potential below 400 mV vs. Ag/AgCl) against high potential chalcopyrite bioleaching (potential above 600 mV vs. Ag/AgCl) in terms of the rate of copper extraction. Microbial growth and the rate of ferrous iron oxidation are essential in order to maintain a high potential during an extended leach period, which was typically the case in the high potential chalcopyrite leaching experiments performed during this study. Ferroplasma JTC 3 required yeast extract as sole carbon source (chemo-heterotrophic) for growth via aerobic ferrous iron oxidation. Taking into account no carbon dioxide enrichment via aeration, chemo-autotrophic growth by means of ferrous iron oxidation was poor with carbon dioxide as sole carbon source. The anaerobic metabolism of Ferroplasma JTC 3 was utilized in assisting with solution potential control during the low potential chalcopyrite leaching work. The anaerobic metabolism enabled the reduction of ferric iron (decrease redox potential) in the presence of elemental sulphur and yeast extract. Elemental sulphur was shown to be a requirement for Ferroplasma JTC 3 assisted ferric iron reduction, which was not influenced by different ferrous/ferric iron based redox potentials. The third section covers the main focus of this study, which was the low potential leaching of chalcopyrite in combination with the metabolic capabilities of Ferroplasma JTC 3. The major challenge of low potential chalcopyrite leaching in an acidic environment is maintaining the solution potential below the critical upper limit (400 mV vs. Ag/AgCl) of the low potential window for prolonged periods of time. The reason is the slow chemical oxidation of ferrous iron in the presence of oxygen, which increases the leach solution potential above the critical upper limit before complete copper dissolution is obtained. The aim of this study was to maintain a low solution potential environment in a bioreactor via a programmable electronic gas control system, capable of creating an aerobic environment until the solution potential would reach the upper low potential limit (400 mV vs. Ag/AgCl) due to ferrous iron oxidation (chemically or via Ferroplasma JTC 3) and then switch to an anaerobic environment. During the anaerobic environment, the aim was to decrease the solution potential to a lower potential set point via chalcopyrite oxidation by ferric iron (ferric iron reduction) and by employing the ferric iron reduction metabolism of Ferroplasma JTC 3. With the particular aerobic/anaerobic solution potential control system, in conjunction with the metabolic capabilities of Ferroplasma JTC 3, the solution potential could be controlled within the critical low potential region, but no chalcopyrite leaching could be obtained during the anaerobic phase. The lack of chalcopyrite leaching during the anaerobic phase was due to inability of ferric iron to act as oxidant of chalcopyrite after the mineral was pre-leached in the preceding aerobic phase. The “oxidative acid leach” mechanism was identified as the dominant leach reaction that prevailed during the aerobic low potential stage in each of the aerobic/anaerobic control experiments conducted, in which oxygen acts as oxidant of chalcopyrite (electron acceptor) in the presence of protons (H+) (acidic environment), instead of ferric iron in an acid environment. The “boundary potential”, which is the maximum solution where no electron flow occurred to the ferrous/ferric couple from “pre-leached” chalcopyrite, was identified in the region of 450 mV (Ag/AgCl). Under the experimental conditions within this study, the leaching of chalcopyrite within the aerobic phase of the aerobic/anaerobic control experiments was superior to the Ferroplasma JTC 3 mediated high potential leaching, but complete copper dissolution could not be obtained with the combined aerobic and anaerobic system. Ferric iron precipitation as a function of pH was proposed as a tool for solution potential control, instead of controlling the potential by limiting oxygen to the leach system. In controlling the solution potential via pH, almost complete copper dissolution from chalcopyrite was obtained, while maintaining the solution potential below the critical upper limit of the low potential region.
Fosso-Kankeu, Elvis. "Ni²⁺ extraction from low grade leachate of tailing dumps materials using cloned indigenous bacterial species". Thesis, 2012. http://hdl.handle.net/10210/8033.
Pełny tekst źródłaRamcharan, Karishma. "Microbial biotransformation of kimberlite ores". Thesis, 2008. http://hdl.handle.net/10413/541.
Pełny tekst źródłaThesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2008.
Selvi, S. Chirpa. "Electrobioleaching Of Sphalerite Flotation Concentrate". Thesis, 1997. https://etd.iisc.ac.in/handle/2005/1799.
Pełny tekst źródłaSelvi, S. Chirpa. "Electrobioleaching Of Sphalerite Flotation Concentrate". Thesis, 1997. http://etd.iisc.ernet.in/handle/2005/1799.
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