Publication: Biolixiviación de minerales sulfurados de cobre de baja ley
Loading...
Files
Official URL
Full text at PDC
Publication Date
2018-11-08
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad Complutense de Madrid
Citations
Exportar
Abstract
En la actualidad, la mayor parte de la industria minera del cobre a nivel mundial enfrenta diversas dificultades en la producción de este metal. Entre los desafíos que se presentan podemos destacar la progresiva disminución de las leyes del mineral, la mayor dureza de las rocas, la fuerte caída de los precios de las materias primas y la disminución de la productividad en el sector. Estas problemáticas han forzado que las compañías mineras se vean en la necesidad de procesar un mayor y más complejo volumen de mineral. Este escenario impulsa la necesidad de innovar tecnológicamente para mantener los niveles de producción de cobre de acuerdo con las necesidades del mercado. En esta Tesis Doctoral se investigaron a escala de laboratorio, los parámetros operacionales relevantes del sistema, así como los cambios mineralógicos y la dinámica microbiológica en el proceso de biolixiviación para minerales sulfurados de cobre de baja ley. En primer lugar, se estudió el comportamiento de algunos de los factores más importantes en una operación de biolixiviación, tales como la disponibilidad de ácido, el efecto de la temperatura del sistema y la actividad microbiana, para poder tener un mejor criterio en el control del proceso industrial. Se evaluó la influencia de la temperatura y de diferentes concentraciones de hierro total en la disolución de la covelina presente en minerales sin procesar y previamente procesados por lixiviación. Se realizó un seguimiento de las transformaciones que experimentan los minerales sulfurados durante el ciclo de lixiviación para comprender y predecir, a su vez, el comportamiento de las poblaciones microbianas tanto en la fase mineral como en la disolución. Finalmente, se innovó en la recuperación de cobre a partir de minerales sulfurados refractarios, con el estudio de la influencia de la adición de ion cloruro en el proceso de biolixiviación. Los resultados obtenidos demostraron que el aumento de la temperatura favorece la actividad bacteriana y la recuperación de cobre, además se puso de manifiesto la importancia de trabajar a 50 °C con el fin de lixiviar eficientemente el cobre contenido en la covelina, ya sea sin tratar o tratada, pero también se evidenció la ventaja potencial de tratar este tipo de mineral a temperaturas más bajas (30 °C) a nivel industrial. El estudio comparativo de las comunidades microbianas presentes en los minerales y en las disoluciones, tanto en los ensayos en columna como en las pilas industriales, ha demostrado suficiente similitud, por lo que se puede considerar que los resultados obtenidos en la disolución son un indicador de la de la población bacteriana en el lecho de la pila. Además, se determinó que los microorganismos predominantes en las experiencias en columna e industriales fueron A. thiooxidans, A. ferrooxidans D2, y L. ferriphilum tanto en la disolución de percolado como en el mineral. Finalmente, se demostró que el uso combinado de microorganismos y cloruro produjo mayor recuperación de cobre en los ensayos de biolixiviación de sulfuros refractarios. Estos resultados abren la posibilidad de desarrollar una nueva tecnología para el tratamiento de minerales de baja ley a nivel industrial, que permitiría optimizar el uso del recurso hídrico de agua fresca o, en su defecto, utilizar agua más salina o, incluso, agua de mar.
Nowadays, copper mining industry is facing several difficulties in order to increase or even maintain copper production. Among the challenges are: progressive decreasing of grade, increasing hardness of rocks, price instability and production declining. These conditions have forced mining companies to process higher amounts of ore with more complex characteristics. In this scenario, technological innovations are necessary to enhance the efficiency in the production of copper. In this doctoral thesis, several operational parameters influencing the bioleaching of low-grade copper sulfide ore were investigated, as well as, mineralogical changes and microbial dynamics. In first place, the behaviour of some of the more important parameters in a heap bioleaching operation was studied, such as acid availability, effect of temperature and microbial activity in order to improve criteria regarding the control during industrial operation. The influence of temperature and different concentrations of total iron in the dissolution of covellite were assessed, when fresh or previously processed ore were treated. Mineralogical changes occurring during leaching cycle were monitored in order to understand and predict the microbial population behaviour either in the solid or liquid phase. The results obtained by the study of the influence of chloride ions in the bioleaching process can be used to sketch an innovative bio-process. The results showed that microbial activity and copper recovery are favoured by increasing the temperature, in addition it is highlighted the effect of working temperatures above 50 °C to efficiently leach covellite included either in the processed or in fresh ore, although certain advantage can be obtained at more suitable temperatures at industrial level (30 °C). The comparison of planktonic and bentonic microbial communities, either at column tests or from industrial heap samples showed elevated similarities, which strongly suggests that results based on the analysis of solutions samples are representative of the microbial populations inhabiting the solid phase of the system in an industrial bioleaching heap. The dominant organisms in column tests and industrial samples were A. thiooxidans, A. ferrooxidans D2, and L. ferriphilum in both, liquid or solid samples. Finally, it was demonstrated that bioleaching of refractory sulphide ore using chloride ions in combination with microorganisms produced a higher copper recovery than only using microorganisms. These results support the possibility to develop a novel technology to treat refractory low grade ore at industrial allowing mining companies a better management of water or even using a saline water source, including sea water, especially in arid zones where fresh water is a scarce resource.
Nowadays, copper mining industry is facing several difficulties in order to increase or even maintain copper production. Among the challenges are: progressive decreasing of grade, increasing hardness of rocks, price instability and production declining. These conditions have forced mining companies to process higher amounts of ore with more complex characteristics. In this scenario, technological innovations are necessary to enhance the efficiency in the production of copper. In this doctoral thesis, several operational parameters influencing the bioleaching of low-grade copper sulfide ore were investigated, as well as, mineralogical changes and microbial dynamics. In first place, the behaviour of some of the more important parameters in a heap bioleaching operation was studied, such as acid availability, effect of temperature and microbial activity in order to improve criteria regarding the control during industrial operation. The influence of temperature and different concentrations of total iron in the dissolution of covellite were assessed, when fresh or previously processed ore were treated. Mineralogical changes occurring during leaching cycle were monitored in order to understand and predict the microbial population behaviour either in the solid or liquid phase. The results obtained by the study of the influence of chloride ions in the bioleaching process can be used to sketch an innovative bio-process. The results showed that microbial activity and copper recovery are favoured by increasing the temperature, in addition it is highlighted the effect of working temperatures above 50 °C to efficiently leach covellite included either in the processed or in fresh ore, although certain advantage can be obtained at more suitable temperatures at industrial level (30 °C). The comparison of planktonic and bentonic microbial communities, either at column tests or from industrial heap samples showed elevated similarities, which strongly suggests that results based on the analysis of solutions samples are representative of the microbial populations inhabiting the solid phase of the system in an industrial bioleaching heap. The dominant organisms in column tests and industrial samples were A. thiooxidans, A. ferrooxidans D2, and L. ferriphilum in both, liquid or solid samples. Finally, it was demonstrated that bioleaching of refractory sulphide ore using chloride ions in combination with microorganisms produced a higher copper recovery than only using microorganisms. These results support the possibility to develop a novel technology to treat refractory low grade ore at industrial allowing mining companies a better management of water or even using a saline water source, including sea water, especially in arid zones where fresh water is a scarce resource.
Description
Tesis de la Universidad Complutense de Madrid, Facultad de Ciencias Químicas, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, leída el 14/02/2018