ABSTRACT
La biolixiviación, usando consorcios microbianos, es considera una alternativa ecoeficiente y de bajo costo para la recuperación de metales a partir de minerales de baja ley. En este estudio, se realizó la caracterización fisiológica y molecular de consorcios microbianos psicrotolerantes lixiviantes (CMPL), aislados de drenajes ácidos de minas de cuatro localidades mineras de las provincias de Pasco y Huarochirí, Perú, ubicados sobre los 4200 m de altitud. Se aislaron seis consorcios adaptados a medio 9K con ion ferroso y medio basal 9K con CuS al 0.5% p/v a 15 °C. Se evidenció la liberación de cobre en todos los consorcios. El CMPL con mejor crecimiento, presentó una recuperación de cobre de 12.47% en 30 días de evaluación. Los análisis de la secuenciación del gen ARNr 16S de la comunidad bacteriana, mostraron que los CMPL están dominados por el género Acidithiobacillus, seguido de Acidiphilium. En conclusión, se obtuvieron consorcios que pueden ser aplicados en biolixiviación de cobre en la minería altoandina.
Bioleaching, using microbial consortia, is regarded as an eco-efficient and cost-effective alternative for the recovery of metals from low-grade ores. In this study, we conducted physiological and molecular characterization of psychrotolerant leaching microbial consortia (PLMC) isolated from acid mine drainage in four mining sites within the Pasco and Huarochirí provinces of Peru, situated at altitudes above 4200 meters. Six consortia adapted to a medium containing ferrous ions (9K medium) and a basal medium with 0.5% w/v CuS at 15°C were isolated. All consortia exhibited copper release. The PLMC with the most robust growth achieved a copper recovery of 12.47% within 30 days of evaluation. 16S rRNA gene sequencing analysis of the bacterial community revealed that the PLMCs were predominantly dominated by the genus Acidithiobacillus, followed by Acidiphilium. In conclusion, consortia suitable for copper biolixiviation in high-altitude mining contexts were successfully obtained.
ABSTRACT
Typical solid wastes contain many metal resources, which are worthy of recycling. The bioleaching of typical solid waste is affected by multiple factors. Green and efficient recovery of metals based on the characterization of leaching microorganisms and the elucidation of leaching mechanisms may contribute to the implementation of China's "dual carbon" strategic goals. This paper reviews various types of microorganisms used for leaching metals from typical solid wastes, analyzes the action mechanism of metallurgical microorganisms, and prospects the application of metallurgical microorganisms to facilitate the application of metallurgical microorganisms in typical solid wastes.
Subject(s)
Solid Waste , Metals , Metallurgy , CarbonABSTRACT
BACKGROUND: Acidithiobacillus ferrooxidans is a facultative anaerobe that depends on ferrous ion oxidation as well as reduced sulfur oxidation to obtain energy and is widely applied in metallurgy, environmental protection, and soil remediation. With the accumulation of experimental data, metabolic mechanisms, kinetic models, and several databases have been established. However, scattered data are not conducive to understanding A. ferrooxidans that necessitates updated information informed by systems biology. RESULTS: Here, we constructed a knowledgebase of iron metabolism of A. ferrooxidans (KIMAf) system by integrating public databases and reviewing the literature, including the database of bioleaching substrates (DBS), the database of bioleaching metallic ion-related proteins (MIRP), the A. ferrooxidans bioinformation database (Af-info), and the database for dynamics model of bioleaching (DDMB). The DBS and MIRP incorporate common bioleaching substrates and metal ion-related proteins. Af-info and DDMB integrate nucleotide, gene, protein, and kinetic model information. Statistical analysis was performed to elucidate the distribution of isolated A. ferrooxidans strains, evolutionary and metabolic advances, and the development of bioleaching models. CONCLUSIONS: This comprehensive system provides researchers with a platform of available iron metabolism-related resources of A. ferrooxidans and facilitates its application.
Subject(s)
Acidithiobacillus/metabolism , Iron/metabolism , Kinetics , Knowledge BasesABSTRACT
BACKGROUND: This paper presents micro- and nano-fabrication techniques for leachable realgar using the extremophilic bacterium Acidithiobacillus ferrooxidans (A. ferrooxidans) DLC-5. RESULTS: Realgar nanoparticles of size ranging from 120 nm to 200 nm were successfully prepared using the highenergy ball mill instrument. A. ferrooxidans DLC-5 was then used to bioleach the particles. The arsenic concentration in the bioleaching system was found to be increased significantly when compared with that in the sterile control. Furthermore, in the comparison with the bioleaching of raw realgar, nanoparticles could achieve the same effect with only one fifth of the consumption. CONCLUSION: Emphasis was placed on improving the dissolvability of arsenic because of the great potential of leachable realgar drug delivery in both laboratory and industrial settings
Subject(s)
Arsenic/metabolism , Sulfides/metabolism , Acidithiobacillus/metabolism , Mining/methods , Arsenic/chemistry , Solubility , Sulfides/chemistry , Temperature , Nanotechnology , Nanoparticles/chemistry , ExtremophilesABSTRACT
Thermoacidophiles can exist in a state of dormancy both in moderate temperatures and even in cold conditions in heap leaching. Sulphide mineral ores such as chalcopyrite produce sulfuric acid when exposed to the air and water. The produced sulfuric acid leads to the decrease of pH and exothermic reactions in heap leaching causing the temperature to increase up to 55 °C and the activation of thermoacidophilic microorganisms. The aim of the present study was to isolate indigenous extreme thermoacidophilic microorganisms at ambient temperature from Sarcheshmeh Copper Complex, to adapt them to the high pulp density of a chalcopyrite concentrate, and to determine their efficiency in chalcopyrite bioleaching in order to recover copper. In this study samples were collected at ambient temperature from Sarcheshmeh Copper Complex in Iran. Mixed samples were inoculated into the culture medium for enrichment of the microorganisms. Pure cultures from these enrichments were obtained by subculture of liquid culture to solid media. Morphological observation was performed under the scanning electron microscope. Isolates were adapted to 30% (w/v) pulp density. For the bioleaching test, the experiments were designed with DX7 software. Bioleaching experiments were carried out in Erlenmeyer flasks and a stirred tank reactor. The highest copper recovery in Erlenmeyer flasks was 39.46% with pulp 15%, inoculums 20%, size particle 90 pm and 160 rpm. The lowest recovery was 3.81% with pulp 20%, inoculums 20%, size particle 40 pm and 140 rpm after 28 days. In the reactor, copper recovery was 32.38%. Bioleaching residues were analyzed by the X-ray diffraction (XRD) method. The results showed no jarosite (KFe3(SO4)2(OH)6) had formed in the bioleaching experiments. It seems that the antagonistic reactions among various species and a great number of planktonic cells in Erlenmeyer flasks and the stirred tank reactor are the reasons for the low recovery of copper in our study.
Los microorganismos termoacidófilos pueden estar en estado latente tanto a temperatura moderada como baja, en lixiviación en pilas. Los minerales sulfurosos, como la calcopirita, producen ácido sulfúrico cuando se exponen al aire y al agua. El ácido sulfúrico producido conduce a la disminución del pH y a reacciones exotérmicas durante la lixiviación en pilas, lo que hace que la temperatura aumente hasta 55 °C y se activen los microorganismos termoacidófilos. El objetivo del presente estudio fue aislar del complejo de cobre Sarchesh-meh (Irán) microorganismos termoacidófilos extremos que proliferan a temperatura ambiente e investigar su adaptación a la alta densidad de pulpa del concentrado de calcopirita, así como su eficiencia para biolixiviarese mineral, con el objeto de recuperar el cobre. Se recogieron muestras a temperatura ambiente del citado complejo, y luego muestras mixtas se inocularon en un medio de cultivo de enriquecimiento. A partir de estos enriquecimientos, mediante el subcultivo del cultivo líquido a medio sólido, se obtuvieron cultivos puros. La observación morfológica se realizó bajo microscopio electrónico de barrido. Los aislados estaban adaptados al 30% p/v de densidad de pulpa. Para la prueba de biolixiviación, los experimentos fueron diseñados con el software DX7. Los experimentos de biolixiviación se llevaron a cabo en Erlenmeyers y en un reactor tanque con agitación. La mayor recuperación de cobre en los Erlenmeyers fue del 39,46% y se obtuvo con la pulpa al 15%, un inóculo del 20%, un tamaño de partícula de 90 µm y una agitación de 160 rpm. La menor recuperación fue del 3,81% y se obtuvo con la pulpa al 20%, un inóculo del 20%, un tamaño de partícula de 40 µm y una agitación de 140 rpm, después 28 días. En el reactor, la recuperación del cobre fue del 32,38%. El análisis de difracción de rayos X (XRD) no mostró que se formara jarosita (KFe3-#91;SO4-#93;2-#91;OH-#93;6) en los experimentos de biolixiviación. Dicha técnica sirve para determinar la estructura cristalina de una sustancia desconocida. Al parecer, las reacciones antagónicas entre las diversas especies y el mayor número de células planctónicas en los Erlenmeyers y en el reactor fueron las causas de la baja recuperación de cobre observada en este estudio.
Subject(s)
Percolation/analysis , Chemical Reactions/analysis , Copper/economics , Causality , Adaptation to Disasters , Hydrogen-Ion ConcentrationABSTRACT
Metals can be leached either directly (physical contact between microorganisms and solid material) or indirectly. The removal of metals from these industrial wastes brings out detoxification of the residues and thus improves the quality of the environment. The waste foundry sand was analyzed for the presence of toxic metals, as the plant uptakes these toxic metals through their food chain which in turn may be harmful to the human beings. In this study Hibiscus was grown on sand blends containing 50% of waste foundry sand (WFS) to assess the availability of Sio2, Al, Ca, Mg, Pb, Cu and Zn. The chemical properties of treated and untreated waste foundry sand were observed. The analysis shows the level of untreated WFS Fe (76.36%), Ca (43.65%) and K (37.49%). Actinomyces sp. was isolated and identified from WFS and was used to bioleach the sand (treated) and was observed to reduce the level of metals present in WFS [Fe (26.54%), Ca (27.67%) and K(5.84%)] and untreated foundry sand had metal levels of [Fe(49.82%), Ca (15.98%) and K(31.65%)]. The treated and untreated sand was later used for growing Hibiscus plant sapling under controlled conditions and was analyzed for the traces of metals absorbed by the plant. The presence of metals was calculated by Atomic Emission Spectroscopy technique that can determine the concentration of trace to major elements. Our observations provide a supportive document on bioleaching of WFS by Actinomyces sp. was adequate in the growth of ornamental plant Hibiscus rosa-sinensis.
ABSTRACT
Precipitation of jarosite is a very important phenomenon that is observed in the bioleaching of pyrrhotite by Acidthiobacillus ferrooxidans (A. ferrooxidans). Jarosite is a major secondary mineral formed in acid supergene environment by oxidation of metal sulphide. The formation of jarosite could decrease leached percentage. The Eh-pH diagram of FeS1.12-H2O showed that the thermodynamic parameters of the jarosite were exists steadily on Eh=360 ï½ 800, pH=2.8 ï½ 5, and the results of pH condition test is consonant with the conclusions of thermodynamic analysis. By means of XRD and SEM, it could indicate that full propagation of A. ferrooxidans in the solution is beneficial to the formation of jarosite and jarosite mediated by bacterial has a better crystalline form than that synthesized by chemical method. This study indicates that pH value and ferrous/ferric iron concentration are key factors affecting the formation of jarosite. Leached percentage is higher when frequency was set more than 2.0. It is crucial to minimize jarosite formation in order to increase factory's efficiency.
A precipitação de jarosite é um fenômeno muito importante que é observado na biolixiviação da pirrotita por Acidithiobacillus ferrooxidans (A. ferrooxidans). A jarosita é um mineral secundário principal formado no ambiente supergênico ácido pela oxidação do sulfureto do metal. A formação de jarosite pode diminuir a porcentagem de lixiviação. O diagrama de Eh-pH de FeS1.12-H2O mostrou que os parâmetros termodinâmicos da jarosite estavam firmemente presentes em Eh = 360~800, pH = 2.8~5, e os resultados do teste de condição de pH estão em consonância com as conclusões da análise termodinâmica. Por meio de XRD e SEM, pode ser indicado que a propagação completa de A. ferrooxidans na solução é benéfica para a formação de jarosite e jarosite mediada por bactérias tem uma forma cristalina melhor do que a sintetizada por método químico. Este estudo indica que o valor do pH e a concentração de ferro ferroso/férrico são fatores chave que afetam a formação de jarosite. A porcentagem de lixiviação é maior quando a freqüência foi ajustada a mais de 2,0. É crucial para minimizar a formação de jarosite, a fim de aumentar a eficiência da fábrica.
Subject(s)
Percolation , Acidithiobacillus , MineralsABSTRACT
Background: Traditional methods of obtaining arsenic have disadvantages such as high cost and high energy consumption. Realgar is one of the most abundant arsenic sulphide minerals and usually treated as waste in industry. The aim of the present study was to screen an arsenic tolerant bacterium used for bioleaching arsenic from realgar. Results: An acidophilic iron-oxidizing bacterium BYQ-12 was isolated from Wudalianchi volcanic lake in northeast China. BYQ-12 was a motile, rod-shaped gram-negative bacterium with an optimum growth at 30°C and pH 2.5. 16S rDNA phylogeny showed that BYQ-12 was a new strain of Acidithiobacillus ferrooxidans. The inhibitory concentrations (ICs) of arsenite and arsenate were 32 and 64 mM, respectively. A significant second-order model was established using a BoxBehnken design of response surface methodology (BBD-RSM) and it estimated that a maximum arsenic bioleaching rate (73.97%) could be obtained when the pulp concentration, pH and initial ferrous ion concentration were set at optimized values of 0.95% w/v, 1.74 and 3.68 g/L, respectively. SEM, EDS and XRD analyses also revealed that there was direct bioleaching besides indirect electrochemical leaching in the arsenic bioleaching system. Conclusion: From this work we were successful in isolating an acidophilic, arsenic tolerant ferrous iron-oxidizing bacterium. The BBD-RSM analysis showed that maximum arsenic bioleaching rate obtained under optimum conditions, and the most effective factor for arsenic leaching was initial ferrous ion concentration. These revealed that BYQ-12 could be used for bioleaching of arsenic from arsenical minerals.
Subject(s)
Arsenic/metabolism , Arsenic/chemistry , Acidithiobacillus/isolation & purification , Oxidation-Reduction , Hydrogen-Ion Concentration , Iron/metabolismABSTRACT
Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetrasulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.
Subject(s)
Humans , Arsenicals/pharmacology , Sulfides/pharmacology , Acidithiobacillus thiooxidans/metabolism , Antineoplastic Agents/pharmacology , Arsenicals/metabolism , Arsenicals/chemistry , Sulfides/metabolism , Sulfides/chemistry , Apoptosis/drug effects , K562 Cells , Cell Line, Tumor , Cell Proliferation/drug effects , Drug Synergism , Toxicological Phenomena , Antineoplastic Agents/chemistryABSTRACT
En este estudio se comparó la actividad oxidativa de dos cepas de Acidithiobacillus ferrooxidans en un proceso de desulfurización, empleando un carbón sub-bituminoso alto en azufre (2.30% de azufre total, con 1.06% pirítico, 1.10% orgánico y 0.14% de sulfatos), proveniente de la mina "La Guacamaya" ubicada en Puerto Libertador -Córdoba, Colombia. Se realizaron ensayos a nivel de erlenmeyer, la concentración de hierro total en la solución fue de 200 mg/L y 1200 mg/L respectivamente, empleando sulfato ferroso. El proceso fue monitoreado mediante mediciones periódicas de los principales factores físico-químicos implicados (pH, potencial de óxido-reducción (Eh), hierro en solución y concentración celular). Según los resultados obtenidos, la mayor eficiencia del proceso se logró, al trabajar con microorganismos compatibles con Acidithiobacillus ferrooxidans y una concentración de sulfato ferroso inicial de 1200 mg/L, el cual obtuvo la mayor tasa de oxidación de pirita (Py oxidada) (68%), así como, mejores condiciones en el medio lixiviante (pH: 1,47; Eh: 625 mV; 6.3×10(8) células/mL) en comparación con el cultivo axénico a las mismas condiciones (Py oxidada: 52%, pH: 1,63, Eh: 580 mV, 5.1×10(8) células/mL), después de 12 días de experimentación.
This study aimed comparing the oxidative activity of two strains of Acidithiobacillus ferrooxidans in a desulphurization process, using a sub-bituminous coal with a high sulfur content (2.30% total sulfur: 1.06% as pyritic, 1.10% as organic and 0.14% from sulfates) from "La Guacamaya" mine, located in Puerto Libertador - Cordoba, Colombia. Several assays were performed in Erlenmeyer flasks, the total iron concentration used in solution were 200 mg/L and 1200 mg/L respectively, using ferrous sulfate. The process was monitored by periodically measuring the main physicochemical factors involved (pH, Eh, cell population and iron in solution). According to the results obtained, the highest efficiency of the process was achieved by working with microorganisms compatible with Acidithiobacillus ferrooxidans and initial concentration of 1200 mg/l of ferrous sulfate, which had higher pyrite oxidation rates (Py oxidized) up to 68% and the best experimental conditions in the leaching medium (pH: 1,47; Eh: 625 mV; 6.3×108 cells/mL), in comparison with the axenic culture on the same conditions (Py oxidized: 52%; pH: 1,63; Eh: 580 mV; 5.1×108cells/mL), after 12 days of experimentation.
ABSTRACT
In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of
Subject(s)
Aspergillus niger/metabolism , Cell Phone , Computers , Copper/metabolism , Electronic Waste , Gold/metabolism , Nickel/metabolism , Polychlorinated Biphenyls/metabolism , Aspergillus niger/enzymology , Aspergillus niger/isolation & purification , Bioreactors/microbiology , Waste Management/methodsABSTRACT
The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum) were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control.
Subject(s)
Bacteria/metabolism , Copper/metabolism , Industrial Microbiology/methods , Microbial ConsortiaABSTRACT
En este estudio se evaluó la adaptación de una cepa compatible con Acidithiobacillus ferrooxidans a altas densidades de pulpa de calcopirita, esfalerita y galena, con dos distribuciones de tamaño de partícula, -200 y -325 serie Tyler de tamices. Los microorganismos fueron adaptados por la disminución gradual de la fuente principal de energía, sulfato ferroso, y el aumento en el contenido de mineral, para finalmente realizar un subcultivo sin la adición de fuente de energía externa. La realización de subcultivos en serie resultó ser una estrategia eficaz para la adaptación a altas densidades de pulpa de esfalerita, calcopirita y galena indicando que el protocolo empleado es adecuado. Los resultados muestran que la cepa compatible con Acidithiobacillus ferrooxidans es más resistente a altas concentraciones de esfalerita, seguido por calcopirita y finalmente por galena. El tamaño de partícula juega un papel fundamental en la adaptación de los microorganismos al mineral.
In this study the adaptation of Acidithiobacillus ferrooxidans-like to high concentrations of chalcopyrite, sphalerite and galena were evaluated with two mineral-particle sizes: 200 and 325 Tyler mesh. The strain was adapted using two simultaneous processes. The first one consisted in a gradual decreasing of the main energy source, ferrous sulphate. The second one consisted in a gradual increasing of the mineral content. Finally, a test was made without ferrous sulphate. The serial subculturing was found to be an efficient strategy to adapt Acidithiobacillus ferrooxidans-like to higher concentrations of chalcopyrite, sphalerite and galena. This indicates that a suitable protocol was employed. The results showed that Acidithiobacillus ferrooxidans-like is more resistant to high concentration of sphalerite, chalcopyrite and galena in descendant order. The particle size played an important role in the adaption of microorganism to the mineral.
Subject(s)
Adaptation, Biological/physiology , Adaptation, Biological/genetics , Adaptation, Biological/immunologyABSTRACT
A novel thermoacidophilic iron and sulfur-oxidizing archaeon, strain YN25, was isolated from an in situ enriched acid hot spring sample collected in Yunnan, China. Cells were irregular cocci, about 0.9-1.02 µm×1.0-1.31 µm in the medium containing elemental sulfur and 1.5-2.22 µm×1.8-2.54 µm in ferrous sulfate medium. The ranges of growth and pH were 50-85 (optimum 65) and pH 1.0-6.0 (optimum 1.5-2.5). The acidophile was able to grow heterotrophically on several organic substrates, including various monosaccharides, alcohols and amino acids, though the growth on single substrate required yeast extract as growth factor. Growth occurred under aerobic conditions or via anaerobic respiration using elemental sulfur as terminal electron acceptor. Results of morphology, physiology, fatty acid analysis and analysis based on 16S rRNA gene sequence indicated that the strain YN25 should be grouped in the species Acidianus manzaensis. Bioleaching experiments indicated that this strain had excellent leaching capacity, with a copper yielding ratio up to 79.16 percent in 24 d. The type strain YN25 was deposited in China Center for Type Culture Collection (=CCTCCZNDX0050).
ABSTRACT
Colemanite is one of the most important underground riches of Turkey, having approximately 60 percent of the world boron deposits, and it has a large portion in the deposits. In this study, chemical leaching and biological leaching methods were used for production of boric acid from colemanite (2CaO · 3B3O3 · 5H2O) (Emet-Kütahya, Turkey). Oxalic acid concentration, temperature, stirring time and solid-to-liquid ratio were taken as parameters in the chemical leaching process. It was found that the dissolution rate increases with increasing oxalic acid concentration and temperature but it decreases at higher solid-to-liquid ratios in the chemical leaching process. Using optimum conditions (d100 = 0.075 mm; 5 percent solids by weight; 0.55 M oxalic acid; 80 +/- 2 ºC leaching temperature; 150 rpm stirring speed; 90 min leaching time) for colemanite sample (28.05 percent B2O3) on chemical leaching with oxalic acid experiments, the calculated boric acid extraction efficiency from colemanite ore was 97.89 percent. Optimum conditions on bioleaching of Emet-Kütahya, Turkey colemanite ores using the fungus Aspergillus niger were found to be as follows: reaction temperature 25 +/- 2ºC; solid-to-liquid ratio 5 percent solids by weight; d100 = 0.075 mm; stirring speed 150 rpm; initial the fungus populations in the inocula about 3 x 10(7) cells/ml and reaction time 21 days. The calculated boric acid extraction efficiency from colemanite ore was 90.18 percent under the optimum conditions. Bioleachate contained 12.95 g/l B2O3, 6.60 g/l Ca and 0.087 g/l Mg. Compared with chemical leaching at 5 percent pulp density, the fungus was less efficient in the extraction of B2O3 from colemanite but the difference in the extraction yields between the two processes was less than 10 percent. Although bioleaching generally requires a longer period of operation compared to chemical leaching, these results suggest that bioleaching by A...
Subject(s)
Aspergillus niger/chemistry , Borates , Boric Acids , Chromatography, High Pressure Liquid , Kinetics , Minerals , Oxalic Acid , Temperature , Time Factors , TurkeyABSTRACT
Covellite oxidation was evaluated with two acidophilic thiobacilli that are important in bioleaching processes.The experiments were carried out in shake flasks in the absence and presence of 4 g/L Fe2+ (as ferrous sulphate) at pH 2.0, 150 rpm and 35 ℃. The tests showed that the copper extraction by the Acidithiobacillus ferrooxidans culture was nearly the same as that by the mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus caldus. On the other hand, additional iron clearly improved Cu leaching.
ABSTRACT
Covellite oxidation was evaluated with two acidophilic thiobacilli that are important in bioleaching processes.The experiments were carried out in shake flasks in the absence and presence of 4 g/L Fe2+ (as ferrous sulphate) at pH 2.0, 150 rpm and 35 ℃. The tests showed that the copper extraction by the Acidithiobacillus ferrooxidans culture was nearly the same as that by the mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus caldus. On the other hand, additional iron clearly improved Cu leaching.
ABSTRACT
Covellite oxidation was evaluated with two acidophilic thiobacilli that are important in bioleaching processes.The experiments were carried out in shake flasks in the absence and presence of 4 g/L Fe2+ (as ferrous sulphate) at pH 2.0, 150 rpm and 35 ℃. The tests showed that the copper extraction by the Acidithiobacillus ferrooxidans culture was nearly the same as that by the mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus caldus. On the other hand, additional iron clearly improved Cu leaching.
ABSTRACT
Bacteria species belonging to the genus Leptospirillum are of great importance in bioleaching industry. This paper introduces the varieties and characteristics of Leptospirillum, its isolation and cultivation methods, as well as the advance of molecular biology and bioleaching mechanism researchs about Leptospirillum.