Samarium-cobalt magnets have a number of high-tech applications such as microwave tubes, gyroscopes, accelerometers, reaction and momentum wheels of satellites, magnetic bearings, sensors, and other energy applications. The growing demand for samarium cobalt (Sm–Co) magnets led to the industry growth from 1300 t in 2008 to above 2000 t in 2020 but at the same time, about 15–30% of the raw materials are wasted as scraps/rejects and swarf at Sm–Co magnet manufacturing sites during shaping and finishing. These production waste and end-of-life Sm-Co magnets are very good secondary resources for cobalt and samarium. However, the current Sm-Co recovery methods rely on aqueous or organic solvent extraction processes that are not energy efficient and environmentally friendly. The present work is aimed to study the reaction of oxygen with SmCl3 and CoCl2 containing chloride melt in terms of possible application in the recycling of Sm–Co scrap to recover samarium and cobalt. The experiments were performed in LiCl–KCl eutectic melt at the temperature range 500–700 oC. The course of the reaction was followed by withdrawing samples after certain time ranges. Samarium (III) and cobalt (II) concentration in the samples was determined by ICP-OES. Bubbling oxygen through the melt containing samarium and cobalt chlorides at temperatures above 500 oC resulted in decreasing samarium concentration while cobalt concentration remains constant. It was found that the samarium precipitation rates are dependent on initial samarium concentration, temperature, and amount of oxygen passed through the melt.

Recovery of samarium from cobalt-samarium chlorides mixture in alkali chloride melts

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