Thesis "EFECTO DE LA UTILIZACIÓN DE SALES OXIDANTES COMO PRETRATAMIENTO DE UN MINERAL AURÍFERO PARA SU POSTERIOR LIXIVIACIÓN"
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Date
2017
Authors
ZUMELZU CORONADO, SEBASTIAN ANDRES
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Abstract
La presente investigación tiene como fin evaluar la incidencia de pretratar químicamente un mineral aurífero en la recuperación por lixiviación de la especie de valor, desde un mineral proveniente de Minera La Florida, Yamana Gold Coporation. Para establecer los parámetros a emplear, así como las potenciales recuperaciones de oro, se utiliza la técnica experimental denominada Extracción Máxima de Especies por Lixiviación Agresiva (EMELA) desarrollada por el Departamento de Ingeniería de Metalurgia y Materiales (DIMM). El mineral fue caracterizado mineralógica, química y físicamente antes del pretratamiento químico.El pretratamiento químico del mineral consiste en adicionar sales oxidantes junto con ácido sulfúrico al mineral de cabeza (se estudiaron dosis del 100, 150, 200, 250 y 300% estequiométrico en base al consumo de ácido sulfúrico), dejando una mezcla homogénea entre los reactivos adicionados y el mineral de cabeza reposar por un determinado tiempo, realizándose experimentos a 5, 10, 15 y 20 días de reposo. La adición de cloruro y nitrato de sodio en conjunto con ácido sulfúrico concentrado, genera agua regia in situ lo que permite disolver las matrices de sulfuros que encapsulan el oro y la plata, aumentando así los porcentajes de extracción en el proceso de lixiviación.Una vez finalizada la etapa de pretratamiento se procedió a realizar un proceso de lixiviación agitada a 400 RPM, utilizando como medio lixiviante una solución clorurada a pH 1 (estudiándose concentraciones de 10, 50, 90 y 120 [g/l] de cloruro), siendo el principal ligante extractor de oro el cloruro presente.Los resultados obtenidos indican que al aumentar los consumos de ácido y concentraciones de cloruro en solución lixiviante se aumentan los porcentajes de extracción de oro y plata, teniendo la etapa de pretratamiento alta incidencia en el valor global de extracción obtenido. De igual manera se observó que tiempos mayores a diez días para la etapa de pretratamiento no presentan gran incidencia sobre los porcentajes de extracción de ambos elementos.Se determinó que para 150% de consumo de ácido, 10 días de pretratamiento, una lixiviación agitada a 400 RPM y 90 [g/l] de concentración de cloruro se alcanzan porcentajes de extracción de oro y plata del orden de 41 y 80 % respectivamente. La extracción de oro se elevó a 83% por medio de un segundo pretratamiento químico. Donde la incidencia del pretratamiento para la extracción de oro es de un 62% y para la plata de un 78% del porcentaje de extracción. La cinética del proceso fue realizada bajo el modelo del núcleo sin reaccionar identificándose un control de tipo químico para las extracciones de ambos elementos en la totalidad de los experimentos efectuados.
The present investigation aims to evaluate the incidence of chemically pretreating a gold ore in the recovery by leaching of the valuable species, from a mineral from Minera La Florida, Yamana Gold Coporation. In order to establish the parameters to be used, as well as the potential recoveries of gold, the experimental technique called Maximum Extraction of Species by Aggressive Leaching (EMELA) developed by the Department of Engineering of Metallurgy and Materials (DIMM) is used. The mineral was characterized mineralogically, chemically and physically prior to chemical pretreatment.The chemical pretreatment of the mineral consists of adding oxidizing salts together with sulfuric acid to the overhead mineral (100, 150, 200, 250 and 300% stoichiometric doses were studied based on the consumption of sulfuric acid), leaving a homogeneous mixture to stand for a Determined time, being carried out experiments at 5, 10, 15 and 20 days. The addition of sodium chloride and nitrate in conjunction with concentrated sulfuric acid generates aqua regia in situ which allows the dissolution of sulphide matrices that encapsulate gold and silver, thus increasing the percentages of extraction in the leaching process.At the end of the pretreatment stage, a leaching process was carried out at 400 RPM, using as leach medium a chlorinated solution at pH 1 (concentrations of 10, 50, 90 and 120 [g/l] chloride was studied), being the main gold extracting binder the chloride present.The results indicate that increasing the acid consumption and chloride concentration in the leach solution increases the extraction rates of gold and silver, the pretreatment step has a high incidence in the overall extract value obtained. Likewise, times greater than ten days were observed for the pretreatment stage and did not present a high incidence on the extraction percentages of both elements.It was determined that for 150% of acid consumption, 10 days of pretreatment, a leaching stirred at 400 RPM and 90 [g/l] chloride concentration, gold and silver extraction rates of 41 and 80% respectively were reached. Where the incidence of pretreatment for the extraction of gold is 62% and for silver of 78%. The kinetics of the process was performed under the unreacted kernel model, identifying a chemical type control for extractions of both elements.
The present investigation aims to evaluate the incidence of chemically pretreating a gold ore in the recovery by leaching of the valuable species, from a mineral from Minera La Florida, Yamana Gold Coporation. In order to establish the parameters to be used, as well as the potential recoveries of gold, the experimental technique called Maximum Extraction of Species by Aggressive Leaching (EMELA) developed by the Department of Engineering of Metallurgy and Materials (DIMM) is used. The mineral was characterized mineralogically, chemically and physically prior to chemical pretreatment.The chemical pretreatment of the mineral consists of adding oxidizing salts together with sulfuric acid to the overhead mineral (100, 150, 200, 250 and 300% stoichiometric doses were studied based on the consumption of sulfuric acid), leaving a homogeneous mixture to stand for a Determined time, being carried out experiments at 5, 10, 15 and 20 days. The addition of sodium chloride and nitrate in conjunction with concentrated sulfuric acid generates aqua regia in situ which allows the dissolution of sulphide matrices that encapsulate gold and silver, thus increasing the percentages of extraction in the leaching process.At the end of the pretreatment stage, a leaching process was carried out at 400 RPM, using as leach medium a chlorinated solution at pH 1 (concentrations of 10, 50, 90 and 120 [g/l] chloride was studied), being the main gold extracting binder the chloride present.The results indicate that increasing the acid consumption and chloride concentration in the leach solution increases the extraction rates of gold and silver, the pretreatment step has a high incidence in the overall extract value obtained. Likewise, times greater than ten days were observed for the pretreatment stage and did not present a high incidence on the extraction percentages of both elements.It was determined that for 150% of acid consumption, 10 days of pretreatment, a leaching stirred at 400 RPM and 90 [g/l] chloride concentration, gold and silver extraction rates of 41 and 80% respectively were reached. Where the incidence of pretreatment for the extraction of gold is 62% and for silver of 78%. The kinetics of the process was performed under the unreacted kernel model, identifying a chemical type control for extractions of both elements.
Description
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Keywords
AGUA REGIA IN SITU , CLORURO , EXTRACCION MAXIMA DE ESPECIES POR LIXIVIACION AGRESIVA (EMELA) , MINERA LA FLORIDA, YAMANA GOLD COPORATION , SALES OXIDANTES