Arsenic containing concentrates are roasted in a fluidized bed to remove 60% to 70% of the arsenic present as arsenic oxide (AsO). The roasted ores can be treated with hydrochloric acid and chlorine or with sulfuric acid to give a leach solution that can be purified by hydrometallurgical methods and from which cobalt can be recovered by electro refining or by carbonate precipitation. If hydrochloric acid is used then cobalt may be extracted using alamine 336 in meta-xylene. Cobalt can be extracted also using dialkylphosphinic acid. When cobalt carbonate (CoCO) is heated (calcined) above 400 °C it decomposes into carbon dioxide (CO) and cobalt(II) oxide (CoO) and can be refined as an oxide concentrate (see above).