Innovaciones técnicas en el tratamiento de aguas acidas de mina con recuperación de subproductos con valor económico
Abstract
La actividad minería genera un gran volumen de materiales y residuos que deben almacenarse adecuadamente en depósitos de desmontes y relaves denominados botaderos o escombreras y relaveras o presas de relaves, por lo general, estos residuos mineros suelen contener sulfuros que en contacto con la atmósfera y agua inician unos complejos procesos de transformaciones físicas, químicas y biológicas, que dan origen a la generación de drenajes ácidos de mina. En los últimos años se han desarrollado metodologías de caracterización más efectiva de las ácidas de mina en el que se incluye además de la acidez protónica la acidez mineral, aspecto que por lo general no se considera en los métodos clásicos de caracterización. También se han potenciado la aplicación de tecnologías emergentes en el control y tratamiento de efluentes como la recuperación de metales de aguas ácidas, tanto si las instalaciones se encuentran en operación o en abandono, mediante el desarrollo de procesos físicos y químicos que modifican las condiciones de Eh y pH de las descargas, de forma que se favorezca la formación de especies insolubles y la retención de la carga metálica disuelta en las aguas. En este trabajo se describen las mejores técnicas disponibles en la caracterización hidrogeoquímica de aguas de mina, junto con procesos innovadores desarrollados para la recuperación de metales y/o subproductos con valor económico de las aguas ácidas de mina. Esta metodología de recuperación de subproductos, además de las mediciones directas en campo de parámetros como: pH, redox, conductividad, oxígeno disuelto, acidez y caudal; se toma muestras representativas para su respectivo análisis en concentraciones totales y disueltas, con esta información se selecciona los reactivos y los tipos de ensayos de neutralización y precipitación para determinar las zonas de hidrólisis de cada elemento presente en el agua y que son objeto de eliminación. A partir de las zonas de hidrólisis o tamponamiento del sistema, identificamos los rangos de pH y redox de los elementos con mayor concentración y elegimos los cortes de las distintas etapas que conformaría el sistema de tratamiento. A partir de los resultados obtenidos en la caracterización de los efluentes se procede a elegir los sistemas de tratamiento mediante ensayos experimentales a nivel de laboratorio para obtener el tamaño de las variables de diseño de la planta de tratamiento de las aguas de mina, que permita la recuperación u obtención de subproductos con posibilidades de aprovechamiento económico. Esta metodología permite dimensionar sistemas de tratamiento de aguas de mina más eficientes, con un menor consumo de reactivos y mejor control ambiental, además, de considerar a los efluentes de mina como fuentes de donde es posible recuperar la carga metálica y obtener un subproducto con aprovechamiento económico. El estudio también incluye casos comparativos del rendimiento económico que se pueden obtener y las recomendaciones para que esta metodología sea viable técnica, ambiental y económica.
Mining activity generates a large volume of materials and waste that must be stored properly in deposits of tailings and tailings called dumps or tailings or tailings dams, usually, these mining waste usually contain sulfides that in contact with the atmosphere and water they initiate complex processes of physical, chemical and biological transformations that give rise to the generation of acid mine drainages. In recent years, methodologies have been developed for more effective characterization of mine acid, in which mineral acidity is included in addition to protonic acidity, an aspect that is not usually considered in classical characterization methods. The application of emerging technologies in the control and treatment of effluents such as the recovery of acidic water metals has also been strengthened, whether the facilities are in operation or abandoned, through the development of physical and chemical processes that modify the conditions of Eh and pH of the discharges, so as to favor the formation of insoluble species and the retention of the dissolved metal load in the waters. This paper describes the best techniques available in the hydrogeochemical characterization of mine waters, together with innovative processes developed for the recovery of metals and / or by-products with economic value from mine acid waters. This method of recovering by-products, in addition to direct measurements in the field of parameters such as: pH, redox, conductivity, dissolved oxygen, acidity and flow rate; representative samples are taken for their respective analysis in total and dissolved concentrations, with this information the reagents and the types of neutralization and precipitation tests are selectedto determine the hydrolysis zones of eachelement present inthe water and that are subject to elimination. From the zones of hydrolysis or buffering of the system, we identify the pH and redox ranges of the elements with the highest concentration and we choose the cuts of the different stages that would form the treatment system. Based on the results obtained in the characterization of the effluents, we proceed to choose the treatment systems through experimental tests atthe laboratory levelto obtainthe size of the design variables ofthe mine water treatment plant, which allows the recovery or obtaining by-products with possibilities of economic use. This methodology allows the sizing of more efficient mine water treatment systems, with a lower consumption of reagents and better environmental control, in addition to considering mine effluents as sources from where it is possible to recover the metallic load and obtain a by-product with use economic. The study also includes comparative cases of economic performance that can be obtained and recommendations for this methodology to be technically, environmentally and economically feasible.
Mining activity generates a large volume of materials and waste that must be stored properly in deposits of tailings and tailings called dumps or tailings or tailings dams, usually, these mining waste usually contain sulfides that in contact with the atmosphere and water they initiate complex processes of physical, chemical and biological transformations that give rise to the generation of acid mine drainages. In recent years, methodologies have been developed for more effective characterization of mine acid, in which mineral acidity is included in addition to protonic acidity, an aspect that is not usually considered in classical characterization methods. The application of emerging technologies in the control and treatment of effluents such as the recovery of acidic water metals has also been strengthened, whether the facilities are in operation or abandoned, through the development of physical and chemical processes that modify the conditions of Eh and pH of the discharges, so as to favor the formation of insoluble species and the retention of the dissolved metal load in the waters. This paper describes the best techniques available in the hydrogeochemical characterization of mine waters, together with innovative processes developed for the recovery of metals and / or by-products with economic value from mine acid waters. This method of recovering by-products, in addition to direct measurements in the field of parameters such as: pH, redox, conductivity, dissolved oxygen, acidity and flow rate; representative samples are taken for their respective analysis in total and dissolved concentrations, with this information the reagents and the types of neutralization and precipitation tests are selectedto determine the hydrolysis zones of eachelement present inthe water and that are subject to elimination. From the zones of hydrolysis or buffering of the system, we identify the pH and redox ranges of the elements with the highest concentration and we choose the cuts of the different stages that would form the treatment system. Based on the results obtained in the characterization of the effluents, we proceed to choose the treatment systems through experimental tests atthe laboratory levelto obtainthe size of the design variables ofthe mine water treatment plant, which allows the recovery or obtaining by-products with possibilities of economic use. This methodology allows the sizing of more efficient mine water treatment systems, with a lower consumption of reagents and better environmental control, in addition to considering mine effluents as sources from where it is possible to recover the metallic load and obtain a by-product with use economic. The study also includes comparative cases of economic performance that can be obtained and recommendations for this methodology to be technically, environmentally and economically feasible.
Description
Vol. 4, No. 1