Thesis LIXIVIACIÓN DE SULFUROS DE COBRE DE BAJA LEY PRETRATADOS CON NaCl – H2SO4 JUNTO CON NaNO3 O Fe(NO3)3, EN MEDIO SULFATO-CLORURO CON NaNO3 Y Fe (NO3)3, EN MEDIO SULFATO CLORURO
Date
2018
Authors
SOTO MELLADO, RICARDO ANDRES
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Abstract
Actualmente la minería chilena se está enfrentado a procesar minerales de cobre altamente calcopiríticos, lo que se ve reflejado en una deficiencia significativa en la alimentación a las plantas de lixiviación, resultando en un aumento del consumo energético en las mineras por preferir un proceso más costoso, que es la vía por chancado – molienda – flotación.En los últimos años se ha investigado el uso del cloruro de sodio en el pretratamiento a los minerales de cobre sulfurados de baja ley, obteniendo resultados mejores a lo que es una lixiviación convencional. Considerando esto, y además el hecho de que Chile es un país donde abunda el salitre, mineral rico en nitratos, es que se resulta interesante realizar una investigación sobre pretratamientos donde se utilicen tanto cloruro de sodio, como sales nitratadas, y ver su posterior comportamiento en una lixiviación en medio cloruro-sulfato.El pretratamiento del mineral sulfurado de cobre, con ley de 0,12% de cobre, se realiza mediante la dosificación de cloruro de sodio sólido (70% estequiométrico), ácido sulfúrico concentrado respecto a su consumo estándar (20, 50, 80 y 100%) y 50% de la humedad de impregnación. La mezcla sólida se deja reposar por 7, 14 y 21 días. El mineral pretratado se somete a una lixiviación agitada bajo condiciones de pH 1, 25% de sólidos, 370 rpm, 4 horas, concentración de cloruros 0, 35 y 70 g/L, y temperaturas tanto ambiental como a 25 y 35 °C.La máxima extracción de cobre obtenida se logró a las siguientes condiciones: pretratamiento con 80% del consumo de ácido estándar, razón de ácidos clorhídrico y nítrico formados 5:1 considerando el 70% del cloruro de sodio estequiométrico, 50% de la humedad de impregnación con un tiempo de reposo de 14 días, lixiviación realizada con una solución lixiviante 70 g/L de ion cloruro, alcanzándose una extracción de 27%.La cinética de disolución se ajustó al modelo del núcleo sin reaccionar. La energía de activación obtenida fue de 36,5 kJ/mol, valor característico de una cinética controlada por difusión en la capa de productos.
In these days, Chilean mining industry is being confronted to process chalcopyrite ores, which is demonstrated in the less feeding to leaching plants, thus the energy consume is on raise due to preferring the flotation route.Recently the use of sodium chloride in pre-treated low grade sulphurous copper minerals has been investigated with better results than a conventional leaching process. Considering this and the fact that Chile has saltpeter in abundancy, which is a nitrate rich mineral, it’s necessary to do research of pretreatments where sodium chloride and nitride salts are used and analyze its behavior on a chloride-sulfate media leaching process.The pretreatment of the low grade sulphurous copper mineral, with a 0,12% Cu, is carried out by the dosage of solid sodium chloride (70% stoichiometric), concentrate sulfuric acid with respect to its standard consume (20, 50, 80 and 100) and 50% of its impregnation humidity. The solid mixture is left to rest for 7, 14 and 21 days. Subsequently, the pretreated mineral is subjected to a stirred leaching process under the conditions: pH 1, 25% solids, 370 rpm, 4 hours, chloride ion concentration of 0, 35 and 70 g/L, and room temperature, 25 and 35 °C.The maximum extraction was obtained under this conditions: pretreatment with 80% of standard acid consume, generation of hydrochloric acid and nitric acid on a 5:1 ratio, assuming the 70% of the stoichiometric sodium chloride, 50% its impregnation humidity with 14 days of resting time, the leaching procesos was done with a leaching solution with 70 g/L of chloride ion, reaching a 27% of copper extraction.The dissolution kinetic was adjusted to the shrinking core model. The obtained activation energy was 36,5 kJ/mol, which is distinctive of a control governed by diffusion of ions by the products layer.
In these days, Chilean mining industry is being confronted to process chalcopyrite ores, which is demonstrated in the less feeding to leaching plants, thus the energy consume is on raise due to preferring the flotation route.Recently the use of sodium chloride in pre-treated low grade sulphurous copper minerals has been investigated with better results than a conventional leaching process. Considering this and the fact that Chile has saltpeter in abundancy, which is a nitrate rich mineral, it’s necessary to do research of pretreatments where sodium chloride and nitride salts are used and analyze its behavior on a chloride-sulfate media leaching process.The pretreatment of the low grade sulphurous copper mineral, with a 0,12% Cu, is carried out by the dosage of solid sodium chloride (70% stoichiometric), concentrate sulfuric acid with respect to its standard consume (20, 50, 80 and 100) and 50% of its impregnation humidity. The solid mixture is left to rest for 7, 14 and 21 days. Subsequently, the pretreated mineral is subjected to a stirred leaching process under the conditions: pH 1, 25% solids, 370 rpm, 4 hours, chloride ion concentration of 0, 35 and 70 g/L, and room temperature, 25 and 35 °C.The maximum extraction was obtained under this conditions: pretreatment with 80% of standard acid consume, generation of hydrochloric acid and nitric acid on a 5:1 ratio, assuming the 70% of the stoichiometric sodium chloride, 50% its impregnation humidity with 14 days of resting time, the leaching procesos was done with a leaching solution with 70 g/L of chloride ion, reaching a 27% of copper extraction.The dissolution kinetic was adjusted to the shrinking core model. The obtained activation energy was 36,5 kJ/mol, which is distinctive of a control governed by diffusion of ions by the products layer.
Description
Catalogado desde la version PDF de la tesis.
Keywords
LIXIVIACION , PRETRATAMIENTO , SALES NITRATADAS