Bioleaching of manganese (IV) oxide and application to its recovery from ores

Bioleaching of manganese (IV) oxide with Thiobacillus thiooxidans has been studied in media with and without sulfur, ferrous sulfide and ferrous sulfate. The knowledge of the role played by the bacteria and the reducing substances suggest that the leaching of manganese (IV) ores through the use of thiobacteria is only justified when suitable amounts of sulfur or metal sulfides are present.Facultad de Ciencias ExactasCentro de Tecnología de Recursos Minerales y CerámicaComisión de Investigaciones Científicas de la provincia de Buenos Aire

Direct and indirect mechanisms in the bacterial leaching of covellite

Bacterial leachings of sample of covellite using a strain of Thiobacillus ferrooxidans in 9 K medium with and without iron were made at several pulp densities. Rates of solubilization with and without iron correspond to total and to direct mechanism respectively. Orders of reaction (at each pulp density) for each mechanism at two temperatures were calculated.Facultad de Ciencias Exacta

Bioleaching of a manganese and silver ore

Con el fin de valorar sus posibilidades de aplicación a Ia disolución y recuperación del manganeso contenido y de mejorar el rendimiento en Ia extracción de plata, se ha sometido a lixiviación, utilizando una cepa de Thiobacillus thiooxidans, mineral procedente del yacimiento de Farallón Negro (Catamarca, Argentina). Hasta ahora, la empresa estatal que explota el yacimiento no ha encontrado un procedimiento económico para Ia separación del manganeso y sólo ha conseguido un rendimiento del 30 % en la recuperación de la plata por cianuración. Se han estudiado los efectos de la variación de la densidad de pulpa y de la adición de diferentes cantidades de FeS al mineral intentando encontrar las condiciones óptimas de trabajo. Asimismo se ha trabajado con el mineral molido a 74 μm (malla Tyler 200), ya que ese es el tamaño de partícula que se trata en la planta durante el proceso de cianuración.The bioleaching with a strain of Thiobacillus thiooxidans of the ore of Farallon Negro (Catamarca, Argentina) was studied in order to estimate its application to the solution and recovery of the manganese, and to improve the silver extraction. The State company which works the mine has not yet found an economical process to extract the manganese and has only reached a 30% efficiency in the recovery of silver by cianuration. The effects of pulp density variations and the addition of different quantities of FeS were analysed looking for the best working conditions. 74 μm (mesh Tyler 200) of ore particles were used because that is the size used in this plant for the cianuration process.Facultad de Ciencias Exacta

Bioleaching of a manganese and silver ore

Con el fin de valorar sus posibilidades de aplicación a Ia disolución y recuperación del manganeso contenido y de mejorar el rendimiento en Ia extracción de plata, se ha sometido a lixiviación, utilizando una cepa de Thiobacillus thiooxidans, mineral procedente del yacimiento de Farallón Negro (Catamarca, Argentina). Hasta ahora, la empresa estatal que explota el yacimiento no ha encontrado un procedimiento económico para Ia separación del manganeso y sólo ha conseguido un rendimiento del 30 % en la recuperación de la plata por cianuración. Se han estudiado los efectos de la variación de la densidad de pulpa y de la adición de diferentes cantidades de FeS al mineral intentando encontrar las condiciones óptimas de trabajo. Asimismo se ha trabajado con el mineral molido a 74 μm (malla Tyler 200), ya que ese es el tamaño de partícula que se trata en la planta durante el proceso de cianuración.The bioleaching with a strain of Thiobacillus thiooxidans of the ore of Farallon Negro (Catamarca, Argentina) was studied in order to estimate its application to the solution and recovery of the manganese, and to improve the silver extraction. The State company which works the mine has not yet found an economical process to extract the manganese and has only reached a 30% efficiency in the recovery of silver by cianuration. The effects of pulp density variations and the addition of different quantities of FeS were analysed looking for the best working conditions. 74 μm (mesh Tyler 200) of ore particles were used because that is the size used in this plant for the cianuration process.Facultad de Ciencias Exacta

Analysis of molybdenite bioleaching by Thiobacillus ferrooxidans in the absence of iron (II)

Thiobacillus ferrooxidans attachment on MoS2 and Mo dissolution are increased by the addition of the tensioactive agent Tween 80 in absence of iron(II), which suggests that the poor bioleaching of MoS2 is caused by its hydrophobic character. Additionally, inhibition ofThiobacillus ferrooxidans growth by the presence of MoO42− and the effect of variable amounts of Tween 80 on bacteria growth and on MoS2 bioleaching are considered in this paper. Data confirm the need of bacterial attachment to insoluble substrate for bioleaching by the direct mechanism.Facultad de Ciencias Exacta

Use of packed bed bioreactors application to ores bioleaching

The behaviour of glass beads, silicagel and activated carbon particles as bacteria supports for using in backed bed bioreactor has been compared. No important difference was found. Additionally the performance of a bioreactor with glass beads was compared with that of a conventional percolating column in the bioleaching of a copper sulphide ore. Results showed higher copper extraction using the bioreactor.Facultad de Ciencias Exacta

Bioleaching of metallic sulphides withThiobacillus ferrooxidans in the absence of iron (II)

Bioleaching of metallic sulphides withThiobacillus ferrooxidans in the absence of iron (II) was studied using pure sulphides and mixtures. The direct mode of bacterial action was analysed with respect to sulphide solubility, exposed solid surfaces and bacterial attachment to the solids. Bioleaching of mixed sulphides showed enhancement of metal extraction in comparison with pure sulphides which suggests metal extractions would be better from polymetallic sulphide ores than from similar matrices with only one sulphide.Facultad de Ciencias ExactasCentro de Tecnología de Recursos Minerales y Cerámic

Bioleaching of Argentine copper ores

En este trabajo se compara el comportamiento de los principales minerales argentinos de cobre, a base de sulfuros, en el proceso de líxiviación bacteriana. Las técnicas utilizadas fueron las de frascos agitados y columnas percoladoras con aereacíón forzada. Se analizó el efecto de distintas variables, tales como pH, tamaño de partícula y diferentes cepas de Thiobacillus ferrooxidans. Los resultados obtenidos permiten predecir la excelente aplicabilidad industrial del procedimiento, habiéndose logrado extracciones que van del 35 al 90%, en un lapso de 50 días, utilizando columnas percoladoras. Se analizan estos resultados en función de 1a composición química y mineralógica de las muestras.The behavior of the main Argentine copper ores-sulfur based-treated by microbial leaching is analyzed. The leaching was performed in shaked flasks and percolating columns. Different variables, such as pH, particle size and several Thiobacillus ferrooxidans strains were studied in relation to the leaching process. The results allow to predict technical feasibility of this procedure for the studied ores. Percentages of copper extraction between 35 to 90 were obtained in 50 days. The chemical and mineralogical composition of samples were correlated to the obtained results.Facultad de Ciencias Exacta

Direct and indirect mechanisms in the bacterial leaching of covellite

Bacterial leachings of sample of covellite using a strain of Thiobacillus ferrooxidans in 9 K medium with and without iron were made at several pulp densities. Rates of solubilization with and without iron correspond to total and to direct mechanism respectively. Orders of reaction (at each pulp density) for each mechanism at two temperatures were calculated.Facultad de Ciencias Exacta

Bioleaching of Argentine copper ores

En este trabajo se compara el comportamiento de los principales minerales argentinos de cobre, a base de sulfuros, en el proceso de líxiviación bacteriana. Las técnicas utilizadas fueron las de frascos agitados y columnas percoladoras con aereacíón forzada. Se analizó el efecto de distintas variables, tales como pH, tamaño de partícula y diferentes cepas de Thiobacillus ferrooxidans. Los resultados obtenidos permiten predecir la excelente aplicabilidad industrial del procedimiento, habiéndose logrado extracciones que van del 35 al 90%, en un lapso de 50 días, utilizando columnas percoladoras. Se analizan estos resultados en función de 1a composición química y mineralógica de las muestras.The behavior of the main Argentine copper ores-sulfur based-treated by microbial leaching is analyzed. The leaching was performed in shaked flasks and percolating columns. Different variables, such as pH, particle size and several Thiobacillus ferrooxidans strains were studied in relation to the leaching process. The results allow to predict technical feasibility of this procedure for the studied ores. Percentages of copper extraction between 35 to 90 were obtained in 50 days. The chemical and mineralogical composition of samples were correlated to the obtained results.Facultad de Ciencias Exacta