Synthesis of Co-Fe powder using Ultrasonic Spray Pyrolysis and Hydrogen reduction

Abstract

The automotive industry is transitioning from traditional fossil fuel-powered vehicles to electric ones. This change aligns with the growing energy transition and may raise demand for vital metals like nickel and cobalt, essential for battery production. Due to problems with cobalt production from primary sources, switching to secondary sources was the obvious choice. Recycling is seen as an alternative supply option by extracting cobalt from secondary resources. In this study the synthetizes of cobalt powder from the industrial waste solution derived from leaching of industrial polycrystalline diamond blank at temperature range 600-950 C was performed using ultrasonic spray pyrolysis and hydrogen reduction method to recover cobalt. The investigation involved 21 experimental runs using two distinct reactors with varying residence times (7.19 sec and 23 sec) and different precursors solution A (1.12g/l Co, 0.002g/l Fe), solution B (1.87g/l Co, 0.03g/l Fe), solution C (2.81g/l Co, 0.05g/l). The aerosol droplets underwent hydrogen reduction within the temperature range of 600 to 950°C, yielding cobalt powder. The volumetric flow rate of 3 l/min (1 l/min Ar, 2 l/min H2) and a 2-hour reaction time were employed. The effect of the reaction temperature, the concentration of cobalt in the precursor, the residence time, and the on the morphology, composition, specific surface area, and crystal structure of the synthesized iron-cobalt particles was investigated also the collection of particle using magnet. Results indicated that higher temperatures resulted in increased cobalt production. Furthermore, altering the cobalt concentration in the solution influenced particle size, showing that higher concentration led to larger particles. A short residence time (7.9 seconds) at 900°C was found to be more suitable for cobalt nanoparticle synthesis, with spherical particles ranging from 191.1nm to 1222nm. While the potential for powder collection using a magnet was evident, the limited cobalt powder recovery could be attributed to precursor concentration or magnetic strength insufficiency. Despite successful powder capture, addressing the challenge of powder recovery from the tube is crucial.