The method for refining nickel involves the following:
Ni is heated with CO to form volatile nickel tetracarbonyl. Ni+4CO330−350K−−−−−−→Ni(CO)4 At high temperature, nickel tetracarbonyl decomposes to pure Ni. Ni(CO)4450−470K−−−−−−→Ni+4CO This is Mond's process for refining Ni.