A review of processing methods for electric arc furnace dust

The work presents an analytical review of processing methods for industrial waste from the ferrous industry, namely, electric arc furnace dust. The annual emissions of this dust and the source of each dust component are determined. Scientific works on the topic of processing electric arc furnace dust published over the past 20 years are compared and analysed. The major methods for dust processing to recover iron, zinc and other metals include pyro - and hydrometallurgical techniques and their combinations. To date, several high-temperature technologies have been developed that allow zinc-containing dust to be efficiently processed (in particular, the Waelz process and secondary processes). However, many of these technologies have remained at the development stage for various reasons (either requiring considerable capital investments, or being unreliable, energy-intensive and inefficient). It is shown that hydrometallurgical processes are environmentally safe and selective to valuable components and allow technological parameters to be controlled. By selecting a suitable solvent (acidic or alkaline), the required metal can be selectively extracted from dust. In addition, such a technology will be cost-effective even under low contents of the extracted component. Approaches to processing metallurgical dust with inorganic and organic acids and ammonia-based solutions are described. Both conventional processing of electric arc furnace dust on an industrial scale and the laboratory developments recently introduced at zinc production plants (their features, advantages and disadvantages) are discussed. Technologies that allow valuable components in the dust to be extracted and returned to the production cycle are identified.

Synthesis of nanosized nickel zinc ferrite using electric arc furnace dust and ferrous pickle liquor

Electric arc furnace dust (EAFD) and waste pickle liquor (WPL); two major side products of the steel industry with negative environmental impact were used for the synthesis of nickel zinc ferrite (NZF); the important magnetic ceramic material of versatile industrial applications. The structural and magnetic properties of the prepared material were examined which showed good magnetic properties (high saturation magnetization and low coercivity) compared with those synthesized from pure reagents. In the applied process, nano sized nickel zinc ferrite (NZF) with a composition of Nix(Zn + impurities)1−xFe2O4 (where x = 0, 0.25, 0.5, 0.75 and impurities of manganese, magnesium, and calcium were prepared using zinc-containing electric arc furnace dust (EAFD) and waste pickle liquor (WPL). The chemical compositions of the prepared samples were determined using X-ray fluorescence (XRF) analysis. The optimum acetic acid concentration for EAFD treatment was found 2% v/v that decreased Ca content of EAFD by 70.6% without loss of Fe and Zn. The structural and morphological characterization was done by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Field Emission Scanning Electron Microscope (FESEM) to confirm the formation of Ni–Zn ferrite nanoparticles and estimate the particle sizes. The maximum saturation magnetization (Ms) of 73.89 emu/g was achieved at 0.5 Ni content and the minimum coercivity of 2.55 Oe was obtained at 0.25 Ni content.

Reciclaje de EAFD a través de la lixiviación selectiva de zinc con soluciones de citrato: comparación con un ácido inorgánico

Contexto: Los EAFD (Electric Arc Furnace Dust) son materiales con un elevado contenido metálico que no es aprovechado al desconocerse su composición y el enfoque técnico para tratarlos o reciclarlos de manera segura. Aunque es un coproducto rico en zinc, a menudo la recuperación de este metal es una tarea desafiante. Objetivo: Proponer un método para tratar los EAFD mediante la extracción selectiva de zinc por vía hidrometalúrgica, obteniendo un licor rico en zinc para su posterior recuperación y futura aplicación y un sólido rico en hierro para su recirculación en procesos siderúrgicos. Metodología: Los experimentos se realizaron a través de lixiviaciones por agitación empleando soluciones de citrato de sodio a concentración y agitación moderadas, temperatura y presión ambiente. Algunas de las variables de estudio fueron modificadas a fin de establecer las mejores condiciones para el proceso. Resultados: Luego de realizar una correlación de resultados y análisis de variables, se determinó que es posible alcanzar extracciones por encima del 50% de Zn y por debajo del 3% de Fe con el citrato. Además, que una concentración de 0.5 M y proporción S/L de 25g / 1 L son algunas de las condiciones más favorables para el proceso de extracción. Conclusiones: Es posible un aprovechamiento del residuo EAFD mediante ruta hidrometalúrgica empleando un agente orgánico como solución lixiviante. El método permite extraer selectivamente el metal de interés a condiciones de trabajo moderadas.