The
Mond Process, sometimes known as the
Carbonyl Process is a technique created by
Ludwig MondDr Ludwig Mond , was a German-born chemist and industrialist who took British nationality.-Education and career:...
in 1899 to extract and purify
nickelNickel is a chemical element, with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. It is one of the four ferromagnetic elements at about room temperature, other three being iron, cobalt and gadolinium...
. It is done by converting nickel oxides (nickel combined with
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
) into pure nickel.
This process makes use of the fact that
carbon monoxideCarbon monoxide is a colorless, odorless and tasteless gas, yet very toxic to humans. It consists of one carbon atom and one oxygen atom, connected by a covalent double bond and a dative covalent bond...
complexes with
nickelNickel is a chemical element, with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. It is one of the four ferromagnetic elements at about room temperature, other three being iron, cobalt and gadolinium...
readily and reversibly to give
nickel carbonylNickel carbonyl is a colorless organometallic complex that is a versatile reagent, first described in 1890 by Ludwig Mond. It was the first metal simple carbonyl complex to be reported...
. No other element forms a carbonyl compound under the mild conditions used in the process.
This process has three steps:
1.
The
Mond Process, sometimes known as the
Carbonyl Process is a technique created by
Ludwig MondDr Ludwig Mond , was a German-born chemist and industrialist who took British nationality.-Education and career:...
in 1899 to extract and purify
nickelNickel is a chemical element, with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. It is one of the four ferromagnetic elements at about room temperature, other three being iron, cobalt and gadolinium...
. It is done by converting nickel oxides (nickel combined with
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
) into pure nickel.
This process makes use of the fact that
carbon monoxideCarbon monoxide is a colorless, odorless and tasteless gas, yet very toxic to humans. It consists of one carbon atom and one oxygen atom, connected by a covalent double bond and a dative covalent bond...
complexes with
nickelNickel is a chemical element, with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. It is one of the four ferromagnetic elements at about room temperature, other three being iron, cobalt and gadolinium...
readily and reversibly to give
nickel carbonylNickel carbonyl is a colorless organometallic complex that is a versatile reagent, first described in 1890 by Ludwig Mond. It was the first metal simple carbonyl complex to be reported...
. No other element forms a carbonyl compound under the mild conditions used in the process.
This process has three steps:
1. Nickel oxide is
reactedA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. They are studied by chemists under a field of science called chemistry. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, often coming about...
with
SyngasSyngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...
at 200 °C to remove oxygen, leaving impure nickel. Impurities include
ironIron is a metallic chemical element with the symbol Fe and atomic number 26. Iron is a group 8 and period 4 element and is therefore classified as a transition metal. Iron and iron alloys are by far the most common metals and the most common ferromagnetic materials in everyday use...
and
cobaltCobalt is a hard, lustrous, gray metal, a chemical element with symbol Co and atomic number 27. Although cobalt-based colors and pigments have been used since ancient times for making jewelry and paints, and miners have long used the name kobold ore for some minerals, the free metallic cobalt was...
.
- NiO (s) + H2 (g) → Ni (s) + H2O (g)
2. The impure nickel is reacted with excess
carbon monoxideCarbon monoxide is a colorless, odorless and tasteless gas, yet very toxic to humans. It consists of one carbon atom and one oxygen atom, connected by a covalent double bond and a dative covalent bond...
at 50 - 60 °C to form
nickel carbonylNickel carbonyl is a colorless organometallic complex that is a versatile reagent, first described in 1890 by Ludwig Mond. It was the first metal simple carbonyl complex to be reported...
.
- Ni (s) + 4 CO (g) → Ni(CO)4 (g)
3. The mixture of excess carbon monoxide and nickel carbonyl is heated to 220 - 250 °C. On heating, tetracarbonyl nickel decomposes to give nickel:
- Ni(CO)4 (g) → Ni (s) + 4 CO (g)
The decomposition may be engineered to produce powder, but more commonly an existing substrate is coated with nickel. For example, nickel pellets are made by dropping small, hot pellets through the carbonyl gas; this deposits a layer of nickel onto the pellets.
This process has also been used for plating nickel onto other metals, where a complex shape or sharp corners made good results difficult by electroplating. Although the results are good, the toxicity makes it impractical as an industrial process. Such parts are now plated by electroless nickel plating instead.