MINERÍA la mejor puerta de acceso al sector minero EDICIÓN 574 / JULIO 2025 10 finas fácilmente en comparación con el coque, entonces cumple con los requisitos. La investigación sobre combustibles alternativos para reemplazar el coque se llevó a cabo en los últimos años utilizando madera y finos de carbón, por ejemplo. Estos materiales no cumplían con los requisitos, pero las briquetas formadas por carbón vegetal aglomerado con alquitrán de madera fueron técnicamente aprobadas. El alquitrán de madera se utiliza no solo como aglutinante, sino que también contribuye a la dureza de las briquetas y es una fuente de carbono. La determinación de la composición de la briqueta consideró la menor cantidad posible de aglomerante y una mayor resistencia mecánica durante la producción y después del curado. La selección de carbón vegetal con un alto contenido de carbón fijo, bajo contenido de volátiles y cenizas contribuyó a una briqueta con alto poder calorífico y alto carbón fijo. Además, el proceso de producción incluyó la mezcla de los componentes seguida de la etapa de briquetado o compactación, que implicó la aplicación de presión, que contribuyó a la dureza y la etapa de curado, que promovió la liberación de algunos volátiles y humedad, así como la unión de los componentes. Para estudiar el potencial reemplazo del coque por briquetas, se realizaron pruebas en Research regarding alternative fuels to replace coke was conducted in the recent years using wood and charcoal fines, for example. These materials did not meet the requirements, but the briquettes formed by charcoal agglomerated with wood tar were technically approved. The wood tar is used not only as a binder but also contributes to briquette hardness and is a source of carbon. The determination of the briquette composition considered the lowest possible amount of agglomerant and greater mechanical resistance during production and after curing. The selection of charcoal with a high content of fixed carbon, low content of volatiles and ash contributed to a briquette with high heat value and high fixed carbon. In addition, the production process included mixing the components followed by the briquetting stage that involved application of pressure contributing to the hardness, and the curing stage that promoted release of some volatiles and moisture as well as the components binding. To study the potential coke replacement with briquettes, tests were carried out in laboratory, bench muffle, bench kiln and in a pilot kiln. In the muffle and bench kiln, the temperature resistance and reactivity up to 1,200 °C of the briquettes and the coke was tested, compared, and served as a reference to research in the pilot kiln. The pilot Waelz kiln tests were carried out using substitutions up to 50%. Part of the coke was reduced, and the briquettes were fed considering the substitution factor obtained in the bench kiln. The yield was compared with the yield of the blank test (EAFD and coke only). The yield consists in the zinc mass recovered divided by the zinc mass fed. Pilot tests have shown that the briquettes can replace up to 40% of coke while maintaining the same performance and operational stability of the current Waelz process. Substitutions of 40% showed yield equivalent to the blank test. Test with 50% substitution showed 89% yield. To evaluate better substitutions of 50% and above, additional tests will be performed. Due to effectiveness of the briquettes in pilot tests, industrial tests will be carried out. If a 30% substitution is applied to the process, the estimate is to reduce 30% CO2e a year.
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