Evaluación de estrategias para el circuito cleaner en planta molienda y flotación convencional - Codelco División El Teniente.
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Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
Desde el año 2020 hasta la fecha, la planta de Molienda y Flotación Convencional, Codelco División El Teniente ha venido presentando tendencias de recuperación negativas en su circuito global y en específico en su etapa Cleaner. Gracias a los informes realizados por la Gerencia de Proyectos, se observa un alza en la ley de cobre de las colas Scavenger, promediando un 0,4% de ley, con una cantidad de cobre potencial recuperable de 2,27 𝑡𝑡 𝐶𝐶𝐶𝐶𝑑𝑑í𝑎𝑎, la cual es debido a la granulometría gruesa que existe en este flujo, lo que conlleva a dificultades en las etapas de Scavenger y de Remolienda. De esta manera, el presente trabajo tiene como objetivo evaluar las capacidades actuales de ambas etapas, proponiendo nuevos equipos y realizando cambios en el circuito Cleaner actual.
En la etapa Scavenger se identificó una deficiencia de capacidad que limita el tiempo de residencia a 22,3 min, muy por debajo del óptimo estimado de 28,5 min. Por esta razón se propone la reactivación del banco 108 y tenerlo como parte del circuito Scavenger para recuperar gran parte del cobre perdido.
Para la etapa de remolienda se identificó una falta de potencia 703 kW lo que se traduce en falta de capacidad, lo que provoca que el 50% del flujo que debería procesar la remolienda, vaya por un by-pass directo a flotación columnar. Para esto se propone incluir un nuevo equipo de remolienda, en este caso un modelo Vertimill, ya que esta tecnología de molinos verticales evita la sobremolienda, además de que tiene una mayor probabilidad de lograr liberación de materiales de granulometría más fina, es más eficiente energéticamente y se puede configurar para circuitos abiertos o cerrados.
Además, se considera la opción de modificar el circuito de la planta mediante dos alternativas que permitan una mejora considerable sin gastos considerables como compra de equipos. Estas son: 1): Cerrar circuito de remolienda y no retornar el concentrado Scavenger a remolienda. 2): Cerrar circuito de remolienda y separar concentrado pre-Rougher.
La propuesta de cerrar el circuito de remolienda es importante ya que permite tener un mejor control del producto, lo que garantiza el tamaño estimado para que pase a flotación columnar el cual es de 70 – 75% -325#. En ambas opciones se presenta un aumento en la recuperación Global, pasando de un 80,4% (actual) a 85,0% (alternativas propuestas). Además, hay una disminución del flujo másico que pasa por Remolienda, De esta manera, se opta por la alternativa 1 ya que obtiene mejores resultados, considera una menor inversión y hay una mayor certeza en los resultados que se pudieron obtener, ya que la alternativa 2 presenta mayores incertidumbres debido a que se realizaron mayores suposiciones al momento de simular.
Since 2020, the Conventional Grinding and Flotation Plant at Codelco División El Teniente has shown declining recovery trends in its overall circuit, particularly in the Cleaner stage. According to reports issued by the Project Management Department, there has been an increase in the copper grade of the Scavenger tails, averaging 0.4% Cu, which corresponds to a potentially recoverable amount of 2.27 metric tons of copper per day. This loss is mainly attributed to the coarse particle size distribution in this stream, leading to operational challenges in both the Scavenger and Regrinding stages. Therefore, the objective of this study is to evaluate the current capacities of these stages, propose new equipment, and implement modifications to the existing Cleaner circuit. In the Scavenger stage, a capacity constraint was identified, limiting the residence time to 22.3 minutes, significantly below the estimated optimum of 28.5 minutes. As a solution, the reactivation of Bank 108 is proposed to reintegrate it into the Scavenger circuit, thereby recovering a significant portion of the copper currently being lost. For the regrinding stage, a power deficiency of 703 kW was identified, resulting in insufficient capacity. Consequently, 50% of the stream that should be processed through regrinding is bypassed directly to column flotation. To address this, the installation of a new regrinding unit is proposed, specifically a Vertimill, a vertical mill technology that minimizes overgrinding, enhances liberation of fine-grained particles, offers higher energy efficiency, and can be configured for open or closed circuits. Additionally, the study considers two low-investment alternatives for modifying the plant circuit without requiring major equipment purchases: 1.Closing the regrinding circuit and discontinuing the return of Scavenger concentrate toregrinding. 2.Closing the regrinding circuit and separating the pre-Rougher concentrate. The proposal to close the regrinding circuit is important as it allows for better control over the product particle size, ensuring that the feed to column flotation meets the targeted size distribution of 70–75% passing 325 mesh. Both alternatives show an increase in global recovery, from the current 80.4% to 85.0%. Moreover, they result in a reduction of the mass flow processed through regrinding. Ultimately, Alternative 1 is selected as the preferred option, as it delivers better outcomes, requires less investment, and yields more reliable results. In contrast, Alternative 2 entails greater uncertainty due to the number of assumptions required during simulation.
Since 2020, the Conventional Grinding and Flotation Plant at Codelco División El Teniente has shown declining recovery trends in its overall circuit, particularly in the Cleaner stage. According to reports issued by the Project Management Department, there has been an increase in the copper grade of the Scavenger tails, averaging 0.4% Cu, which corresponds to a potentially recoverable amount of 2.27 metric tons of copper per day. This loss is mainly attributed to the coarse particle size distribution in this stream, leading to operational challenges in both the Scavenger and Regrinding stages. Therefore, the objective of this study is to evaluate the current capacities of these stages, propose new equipment, and implement modifications to the existing Cleaner circuit. In the Scavenger stage, a capacity constraint was identified, limiting the residence time to 22.3 minutes, significantly below the estimated optimum of 28.5 minutes. As a solution, the reactivation of Bank 108 is proposed to reintegrate it into the Scavenger circuit, thereby recovering a significant portion of the copper currently being lost. For the regrinding stage, a power deficiency of 703 kW was identified, resulting in insufficient capacity. Consequently, 50% of the stream that should be processed through regrinding is bypassed directly to column flotation. To address this, the installation of a new regrinding unit is proposed, specifically a Vertimill, a vertical mill technology that minimizes overgrinding, enhances liberation of fine-grained particles, offers higher energy efficiency, and can be configured for open or closed circuits. Additionally, the study considers two low-investment alternatives for modifying the plant circuit without requiring major equipment purchases: 1.Closing the regrinding circuit and discontinuing the return of Scavenger concentrate toregrinding. 2.Closing the regrinding circuit and separating the pre-Rougher concentrate. The proposal to close the regrinding circuit is important as it allows for better control over the product particle size, ensuring that the feed to column flotation meets the targeted size distribution of 70–75% passing 325 mesh. Both alternatives show an increase in global recovery, from the current 80.4% to 85.0%. Moreover, they result in a reduction of the mass flow processed through regrinding. Ultimately, Alternative 1 is selected as the preferred option, as it delivers better outcomes, requires less investment, and yields more reliable results. In contrast, Alternative 2 entails greater uncertainty due to the number of assumptions required during simulation.
Description
Tesis presentada para optar al título de Ingeniero/a Civil Metalúrgico/a.
Keywords
Minería, Flotación (Minerales), Sulfuros