6.12 Describe a method for refining nickel.

 

Nickel is refined by Mond’s process. In this process, nickel is heated in the presence of carbon monoxide to form nickel tetracarbonyl, which is a volatile complex.                                                          Ni  + 4CO 330-350K Ni(CO)4                                                        Nickel tetracarbonyl

Then, the obtained nickel tetracarbonyl is decomposed by subjecting it to a higher temperature (450 − 470 K) to obtain pure nickel metal.
                                                               Ni(CO)4  450-470K Ni + 4CONickel                          Nickeltetracarbonyl