Evaluación de un proceso integrado de tratamiento de escorias usando H2V para optimizar la recuperación de cobre y valorizar el Fe en una fundición de concentrados sin residuos.
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Date
2025
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Universidad de Concepción
Abstract
Esta Memoria de Título se enmarca en el proyecto TA 23I10031 financiado por ANID: “Procesamiento sostenible de concentrados de cobre: fusión reductora con hidrógeno verde de calcinas oxidadas y escorias de cobre”.
El estudio tiene como objetivo desarrollar un análisis técnico económico de la modificación de la estructura productiva en el proceso convencional de una fundición de concentrados de cobre operando en una configuración clásica: fusión, conversión y piro-refinación. Este proceso tratará las escorias de fusión y conversión -que convencionalmente son tratadas para recuperar el cobre-, y además aquellas que se recirculan en la estructura productiva: mazamorras y escorias anódicas, es decir, en un solo reactor se tratarán todas las escorias de una fundición.
Esta nueva tecnología se basa en la reducción intensiva de escorias mediante hidrógeno verde como agente reductor, lo que permite maximizar la recuperación de cobre metálico y generar dos coproductos adicionales con valor comercial: hierro metálico (arrabio o hierro fundido) y una escoria secundaria cementicia. La formación de esta última se logra mediante la adición controlada de CaO y Al₂O₃ para alcanzar una proporción 48:12:40 (CaO:Al₂O₃:SiO₂), compatible con los requerimientos de la industria cementera como aditivo o precursor de Clinker.
Desde el punto de vista operativo, se considera una etapa previa de oxidación para eliminar el azufre de la escoria CT, lo que evita la generación de gases tóxicos como H₂S(g) durante la reducción con hidrógeno, mejorando así la seguridad del proceso.
Se analizaron dos alternativas de valorización del hierro: la evaluación se realizó para tratar 240 mil toneladas/año de escoria considerando la producción de arrabio (Caso A) y de hierro fundido (Caso B), con un horizonte de 10 años, una tasa de descuento del 10% y un impuesto a la renta del 27%. Los resultados muestran que ambos casos presentan un Valor Actual Neto (VAN) positivo, lo que indica la viabilidad económica de las alternativas bajo las condiciones evaluadas. Para el Caso A, el VAN varía entre 89 y 114 millones USD, mientras que, en el Caso B, los valores son notablemente más bajos, oscilando entre 6 y 34 millones USD, dependiendo del porcentaje de carga fría. Esta diferencia de rentabilidad se explica principalmente por los mayores ingresos anuales del arrabio, su mejor rendimiento por tonelada de escoria tratada, y un menor consumo energético específico, lo que reduce significativamente los costos operacionales. En conjunto, estos factores posicionan al arrabio como la alternativa más rentable y robusta frente a variaciones operativas dentro del proceso.
Desde un enfoque ambiental y estratégico, la propuesta representa una alternativa altamente relevante: contribuye a la reducción significativa de emisiones de CO₂(g) mediante el uso de hidrógeno verde, permite la revalorización de un pasivo industrial de alto impacto acumulativo como lo son las escorias de cobre, y genera productos con valor agregado destinados a las industrias siderúrgica y cementera. Estos elementos posicionan al proyecto como un caso sólido de economía circular aplicada al sector minero-metalúrgico, con un claro potencial de desarrollo y optimización para su implementación futura.
This Thesis is part of the project “Sustainable Processing of Copper Concentrates: Reductive Smelting with Green Hydrogen of Oxidized Calcines and Copper Slags.” The study aims to perform a techno-economic analysis of modifying the conventional production structure of a copper concentrate smelter operating in a classic configuration—smelting, converting, and fire refining. Under this approach, smelting and converting slags (which are conventionally treated to recover copper) will be processed together with those recycled within the production structure—namely mazamorras and anodic slags—so that all slags from a single smelter are treated in one reactor. This new technology is based on the intensive reduction of slags using green hydrogen as a reducing agent, enabling the maximization of metallic copper recovery and the production of two additional marketable by-products: metallic iron (as pig iron or smelted iron) and a secondary cementitious slag. The latter is obtained through the controlled addition of CaO and Al₂O₃ to achieve a 48:12:40 (CaO:Al₂O₃:SiO₂) ratio, which meets the chemical and physical requirements of the cement industry as an additive or clinker precursor. From an operational perspective, a pre-oxidation stage is considered to remove sulfur from the Teniente converter slag (CT), preventing the formation of toxic gases such as H₂S(g) during hydrogen reduction and enhancing the overall process safety. Two iron recovery alternatives were analyzed based on the processing of 240.000 tons/year of copper slag, considering the production of pig iron (Case A) and smelted iron (Case B). The evaluation was conducted over a 10-year horizon, using a 10% discount rate and a 27% corporate income tax. The results show that both cases yield a positive Net Present Value (NPV), indicating economic feasibility under the evaluated conditions. For Case A, the NPV ranges between 89 and 114 million USD, while Case B exhibits significantly lower values, ranging between 6 and 34 million USD, depending on the proportion of cold slag. This difference in profitability is primarily attributed to the higher annual revenues associated with pig iron, its better yield per ton of slag processed, and its lower specific energy consumption, which substantially reduces operating costs. Collectively, these factors position pig iron as the most profitable and operationally resilient alternative. From an environmental and strategic perspective, the proposed approach represents a technically viable and sustainable solution. It contributes to the reduction of CO₂ emissions through the use of green hydrogen, enables the valorization of industrial waste—such as copper slag, which has a high cumulative environmental impact—and results in value-added products for the steel and cement industries. These attributes establish the project as a practical case of circular economy applied to the mining and metallurgical sector, with clear potential for future development and optimization.
This Thesis is part of the project “Sustainable Processing of Copper Concentrates: Reductive Smelting with Green Hydrogen of Oxidized Calcines and Copper Slags.” The study aims to perform a techno-economic analysis of modifying the conventional production structure of a copper concentrate smelter operating in a classic configuration—smelting, converting, and fire refining. Under this approach, smelting and converting slags (which are conventionally treated to recover copper) will be processed together with those recycled within the production structure—namely mazamorras and anodic slags—so that all slags from a single smelter are treated in one reactor. This new technology is based on the intensive reduction of slags using green hydrogen as a reducing agent, enabling the maximization of metallic copper recovery and the production of two additional marketable by-products: metallic iron (as pig iron or smelted iron) and a secondary cementitious slag. The latter is obtained through the controlled addition of CaO and Al₂O₃ to achieve a 48:12:40 (CaO:Al₂O₃:SiO₂) ratio, which meets the chemical and physical requirements of the cement industry as an additive or clinker precursor. From an operational perspective, a pre-oxidation stage is considered to remove sulfur from the Teniente converter slag (CT), preventing the formation of toxic gases such as H₂S(g) during hydrogen reduction and enhancing the overall process safety. Two iron recovery alternatives were analyzed based on the processing of 240.000 tons/year of copper slag, considering the production of pig iron (Case A) and smelted iron (Case B). The evaluation was conducted over a 10-year horizon, using a 10% discount rate and a 27% corporate income tax. The results show that both cases yield a positive Net Present Value (NPV), indicating economic feasibility under the evaluated conditions. For Case A, the NPV ranges between 89 and 114 million USD, while Case B exhibits significantly lower values, ranging between 6 and 34 million USD, depending on the proportion of cold slag. This difference in profitability is primarily attributed to the higher annual revenues associated with pig iron, its better yield per ton of slag processed, and its lower specific energy consumption, which substantially reduces operating costs. Collectively, these factors position pig iron as the most profitable and operationally resilient alternative. From an environmental and strategic perspective, the proposed approach represents a technically viable and sustainable solution. It contributes to the reduction of CO₂ emissions through the use of green hydrogen, enables the valorization of industrial waste—such as copper slag, which has a high cumulative environmental impact—and results in value-added products for the steel and cement industries. These attributes establish the project as a practical case of circular economy applied to the mining and metallurgical sector, with clear potential for future development and optimization.
Description
Tesis presentada para optar al título de Ingeniera Civil Metalúrgica
Keywords
Escorias de cobre, Desechos metalúrgicos, Tecnología verde