Experimental and theoretical studies of the carbonylation and decarbonylation reactions involving nickel

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One of the leading industrial processes used for the extraction of nickel from processed ores is via the formation and subsequent decomposition of Ni(CO)4, as discovered by Mond, Langer and Quincke in 1890. Exposure of the oxidized ore to pure CO at 80-100 oC produces the volatile and toxic carbonyl; decomposition at 180 oC produces a highly purified Ni solid, which is widely used in the preparation of stainless steels, powder metallurgy, and electrochemical processing and depositions. This mechanism is employed at refineries in Clydach (Wales, UK) and Copper Cliff (Ontario, Canada) operated by Vale (formerly INCO), using Ni ores that are mostly mined in the Sudbury area. Despite the apparent simplicity of the process and its long development, the efficiency of the process is highly variable, and the physico-chemical properties of the final Ni products are less homogeneous than desired for many industrial applications; these quality control variations have significant financial consequences for the associated Ni industry. The origins of these variations are not known, despite extensive industrial testing and empirical adjustments to the ore feedstocks, additives, and operating conditions. Anecdotal evidence from plant operations suggest that poorly controlled S in the reactors may play a crucial role in these variations; S is added deliberately and is also present in the ore matte used for carbonylation.