Publication: TOSTACION DE MOLIBDENITA CON ALTOS CONTENIDOS DE COBRE A NIVEL PILOTO
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Date
2016-07
Authors
SALINAS CLAVIJO, HERNAN ANTONIO
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Abstract
La molibdenita, como un subproducto de la minería del cobre, contiene cantidades de Cobre que pueden
variar entre un 0,2% a 3,5%, dependiendo del origen de dicha molibdenita. Esto ocasiona graves problemas al
momento de su procesamiento, que se agudizan a medida que aumenta el contenido de esta impureza,
provocando la aparición de acreciones, con una alta presencia de azufre y MoO2 en la calcina descargada.
Obtener un trióxido de molibdeno que cumpla con las especificaciones comerciales, esto es, con un azufre
menor o igual a 0,1%, es el objetivo final del proceso de tostación. Para determinar los valores máximos de
cobre permitido en la mezcla, de tal manera de obtener un trióxido de molibdeno comercial, es que se realizan
pruebas a nivel piloto, en las cuales se varió el contenido de cobre en la alimentación, entre valores de 1 a 3%
de Cobre. Para ello, el concentrado de molibdenita con alto contenido de cobre, se mezcla en distintas
proporciones con otras molibdenitas con contenido de cobre bajo, de tal manera de alcanzar valores del orden
de 1%, 2% y 3% de cobre en la mezcla que se alimentará al Horno piloto.
Para lograr determinar la factibilidad de procesamiento, se realizaron pruebas en un Horno piloto de un piso,
simulando las condiciones de un Horno de tipo industrial.
Los resultados obtenidos de estas pruebas muestran que se alcanzan niveles óptimos de procesamiento, para
mezclas con valores de 1% de cobre contenido en la mezcla, esto es, se obtiene un Trióxido de Molibdeno
comercial, con valores de azufre contenido en la calcina inferiores a 1000 ppm.
Para las mezclas cuyos valores de cobre contenido son de 2% y 3%, no se logra alcanzar un resultado óptimo,
con azufres contenido en la calcina por sobre los 1000 ppm, lo que hace inviable su comercialización.
En el estudio realizado, se constató que las recuperaciones de molibdeno fueron favorables para todas las
mezclas utilizadas. La mezcla que contenía un 1% de cobre presentó valores por sobre un 99% de MoO3
contenido. El resto de las mezclas alcanzó valores del orden de un 90% de MoO3 contenido.
Las curvas cinéticas del proceso de tostación fueron obtenidas y posteriormente graficadas, tal como se
detalla en el anexo Gráficos.
Molybdenite, as a byproduct of copper mining, does contain copper amounts varying from 0.2% to 3.5%, depending on the origin of such molybdenite. This causes serious problems at the time of processing, which are exacerbated with the increase of copper, causing the appearance of accretions, with a high presence of sulfur in the calcine and MoO2 discharged. Getting a molybdenum trioxide that meets commercial specifications, that is, less than or equal to 0.1% sulphur, is the ultimate goal of the roasting process. To determine the maximum allowable copper values in the mixture, in order to obtain a commercial molybdenum trioxide, tests are made at pilot scale, in which the copper content in the feed was varied between 1 and 3%. To achieve this goal, the molybdenite concentrate with high copper content is mixed in different proportions with other molybdenites containing low copper, so reaching values of the order of 1%, 2% and 3% copper in the mixture. The tests were performed in a pilot floor furnace, simulating the conditions of an industrial furnace. The results of these tests show that optimum levels of processing are achieved only for mixtures with values of 1% copper content in the mixture, i.e. a commercial molybdenum trioxide is obtained, with sulfur content in the calcined tail of 1000 ppm. Mixtures whose values are copper content are 2% and 3% fail to achieve appropriate results. Calcine sulfur content falls above 1000 ppm, making marketing unfeasible. In the study, it was found that molybdenum recoveries were favorable for all mixtures used. The mixture containing 1% copper showed values over 99% MoO3 content. The rest of the mixtures reached values of about 90% MoO3 content. Kinetic curves were obtained for the roasting process. Plots are available in Annex Graphics.
Molybdenite, as a byproduct of copper mining, does contain copper amounts varying from 0.2% to 3.5%, depending on the origin of such molybdenite. This causes serious problems at the time of processing, which are exacerbated with the increase of copper, causing the appearance of accretions, with a high presence of sulfur in the calcine and MoO2 discharged. Getting a molybdenum trioxide that meets commercial specifications, that is, less than or equal to 0.1% sulphur, is the ultimate goal of the roasting process. To determine the maximum allowable copper values in the mixture, in order to obtain a commercial molybdenum trioxide, tests are made at pilot scale, in which the copper content in the feed was varied between 1 and 3%. To achieve this goal, the molybdenite concentrate with high copper content is mixed in different proportions with other molybdenites containing low copper, so reaching values of the order of 1%, 2% and 3% copper in the mixture. The tests were performed in a pilot floor furnace, simulating the conditions of an industrial furnace. The results of these tests show that optimum levels of processing are achieved only for mixtures with values of 1% copper content in the mixture, i.e. a commercial molybdenum trioxide is obtained, with sulfur content in the calcined tail of 1000 ppm. Mixtures whose values are copper content are 2% and 3% fail to achieve appropriate results. Calcine sulfur content falls above 1000 ppm, making marketing unfeasible. In the study, it was found that molybdenum recoveries were favorable for all mixtures used. The mixture containing 1% copper showed values over 99% MoO3 content. The rest of the mixtures reached values of about 90% MoO3 content. Kinetic curves were obtained for the roasting process. Plots are available in Annex Graphics.
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Keywords
MOLIBDENITA