Nickel is a chemical element, Atomic Number 28 , which is part of the large number of transition metals. It is placed in a group with the metals Iron and Cobalt. It is commonly used as a coating for other metals .
History of Nickel
Towards the end of the seventeenth century, the German expression “Kupfernickel” was applied, meaning “false copper” to copper- like ores, from which no metal could be obtained. Cronstedt showed that these ores contained a metal, which he named Nickel.
Natural State of Nickel
The nickel is in the state of “Kupfer-Niquel” or Niqueline (NiAs), Millerite (NiS), Pentlandite (NiS * 2FeS), and Garnierite, a Silicate complex with Nickel.
The ore is roasted, and the oxide is reduced with carbon to metal, which also contains iron, copper and cobalt. The separation and purification is very complicated.
Physical and Chemical Properties of Nickel
The Nickel is a white Argentine metal, with a slight yellow color . It has an Atomic Weight of 58,693 g / mol. Its density is 8,908 g / ml. Its Melting Point is at 1455 ° C, and its Boiling Point is at 2457 ° C. Its electrical conductivity is 14.3 million Siemens per meter.
It has an impressive ability to adsorb hydrogen gas on its surface , so it serves as a catalyst for hydrogenation reactions.
Thanks to its quality of adsorbing hydrogen on its surface, it is used finely divided, as a catalyst in the reactions of Hydrogenation of Oils.
In addition, it is a metal capable of combining with others in alloys, whose characteristics are described below:
Nichrome (Chromel): Alloy composition 60% Nickel and 40% Chromium . It is characterized by a high Fusion Point, little electrical conductivity, so it is used as a Thread of Thermal Resistances.
Constantan: Alloy consisting of 60% Copper and 40% Nickel , special for the manufacture of Thermoelectric Pairs, also called Thermocouples, which are devices for measuring temperature.
Monel: Special nickel alloy, 72% Nickelcomposition , 26.5% Copper, 1.5% Iron . It is characterized by being stainless, so it is used in the manufacture of propellers, valves, wires, plates, etc.
German Silver: It is an alloy made of 25% Nickel, 25% Zinc, and 50% Copperapproximately. It is an Argentine white alloy, used in the manufacture of costume jewelery and tableware.
Platinite: Alloy formed by 46% Nickel, 54% Iron,and some indications of Carbon, with a small coefficient of expansion, such as glass. It is used for the manufacture of input wires for electric lamps.
Trivalent Nickel salts (valence +3) are known, but they are rare and unstable; those of divalent Nickel (valence +2) are easily prepared. In general they are green, and form hydrates: Ni Nickel Nitrate (NO 3 ) 2 * 6H 2 O; Nickel Chloride NiCl 2 * 6H 2 O; Nickel Sulphate NiSO 4 * 7H 2 O.
The Hydroxide nickelous Ni (OH) 2 is formed as apple green precipitate by adding a soluble base to a solution of nickel salt.
The Hydroxide Niquélico Ni (OH) 3 is a black precipitate formed by adding an oxidant to an alkaline or neutral solution of a salt niquelosa. It is one of the substances used in the poles of the Edison Accumulator.
Nickel forms a compound with Carbon Monoxide, Nickel-Tetra Carbonyl Ni (CO) 4 . It is a colorless liquid. Heating the steam to 200 ° C dissociates, depositing Nickel.
The Mond Method to separate the Nickel from other metals is based on this property of the element; If Carbon Monoxide is passed over the mixed metals, Ni (CO) 4 is formed , which passes through the excess of Carbon Monoxide (CO) to another part of the apparatus, where the temperature is 200 ° C. There the dissociation takes place, and the metal is deposited in the form of a fine powder; Carbon Monoxide can be used again.
Examples of Nickel Compounds and Materials
Ni Nickel Nitrate (NO 3 ) 2 * 6H 2 O
Nickel Chloride NiCl 2 * 6H 2 O
Nickel Sulfate NiSO 4 * 7H 2 O
Nickel Hydroxide Ni (OH) 2
Ni (OH) 3 Niquid Hydroxide
NickelTetraCarbonyl Ni (CO) 4
Nichrome (Chromel): Composition Alloy 60% Nickel and 40% Chromium
Constantan: Alloy consisting of 60% Copper and 40% Nickel
Monel: Alloy, composition 72% Nickel, 26.5% Copper, 1.5% Iron
German Silver: It is an alloy made of 25% Nickel, 25% Zinc, and 50% Copper
Platinite: Alloy formed by 46% Nickel, 54% Iron