NICKEL (

See also:

• SYMBOL (Gr. o-uµ(3oXov, a sign)

symbol Ni, atomic

See also:

• WEIGHT

weight 58.68 (0=16))  , a metallic element . It has been known from the earliest times, being employed by the Chinese in the form of an alloy called pakfong . It was first isolated in an impure condition in 1751 by A . F . Cronstedt from niccolite, and his results were afterwards con-firmed by T . 0 . Bergman in 1775 (De niccolo,opusc . 2, p . 231; 3, p . 459; 4, p . 374) . It occurs in the uncombined condition and alloyed with iron in meteorites; as sulphide in millerite and nickel blende, as arsenide in niccolite and cloanthite, and frequently in combination with arsenic and antimony in the form of complex sulphides .

In

recent years it has been found in considerable quantities in New Caledonia in the form of a hydrated silicate of nickel and magnesia approximating to the constitution (NiO, MgO)Si02.nH20 (J . Garnier, 1865), and in Canada in the form of nickeliferous pyrrhotines, which consist of sulphides of iron associated with sulphides of nickel and copper, embedded in a matrix of gneiss . At the present time nickel is obtained practically entirely from garnierite and the nickeliferous pyrrhotines . When the former is used it is roasted with calcium sulphate or alkali waste to form a matte which is then blown in a Bessemer converter or heated in a reverberatory furnace with a siliceous flux with the object of forming a rich nickel sulphide . This sulphide is then by further heating converted into the oxide and finally reduced to the state of metal by ignition with carbon in clay crucibles . The process adopted for the Canadian ores, which are poor in copper and nickel, consists in a preliminary roasting in heaps and smelting in a blast furnace in order to obtain a matte, which is then further smelted with a siliceous flux for a rich matte . This rich matte is then mixed with coke and salt-cake and melted down in an open hearth furnace . The nickel sulphide so obtained is then roasted to oxide and reduced to metal . For a wet method of extraction nickel salts see A . Riche and Laborde, Jour . Pharm . Chem., 1888, [51, 17, PP- 1, 59, 97 .

Nickel is used for the manufacture of domestic utensils, for crucibles, coinage, plating, and for the preparation of various

alloys, such as German silver, nickel steels such as in-ear (nickel, 35'7%; steel, 64.3%), which has a negligible coefficient of thermal expansion, and constantan (nickel, 45%; copper, 55%), which has a negligible thermal coefficient of its electrical resistance . Compounds . Nickel Oxides.—Several oxides of nickel are known . A suboxide, Ni20 (?), described by W . Muller (Pogg . Ann., 1869, 212, p . 59), is not certainly known . The monoxide, NiO, occurs naturally as bunsenite, and is obtained artificially when nickel hydroxide, carbonate, nitrate or sulphate is heated . It may also be prepared by the action of nickel on water, by the reduction of the oxide Ni203 with hydrogen at about Zoo° C . (H . Moissan, Ann . Chim .

Phys., 151, 21, p . 199), Or by heating nickel chloride with

sodium carbonate and extracting the fused mass with water . It is a green powder which becomes yellow when heated . It dissociates at a red heat, and is readily reduced to the metal when heated with carbon or in a current of hydrogen . It is readily soluble in acids, forming salts, the rate of solution being rapid if the oxide is in the amorphous condition, but slow if the oxide is crystalline . The hydroxide, Ni(OH)2, is obtained in the form of a greenish amorphous powder when nickel salts are precipitated by the caustic alkalis . It is readily soluble in acids and in an aqueous solution of ammonia . Nickel sesquioxide, NizOi, is formed when the nitrate is decomposed by heat at the lowest possible temperature, by a similar decomposition of the chlorate, or by fusing the chloride with potassium chlorate . It is a black powder, the composition of which is never quite definite, but approximates to the formula given above . When heated with oxy-acids it dissolves, with evolution of oxygen, and with hydrochloric acid it evolves chlorine . Numerous hydrated forms of the oxide have been de-scribed (see W . Wernicke, Pogg .

Ann., 187o, 17, p . 122) . A peroxide, NiO,, has been obtained in the form of dinickelite of

barium, BaO.2NiO2, by heating the monoxide with anhydrous baryta in the electric furnace (E . Dufau, Comptes rendus, 1896, 123, p . 495) . G . Pellini and D . Meneghini (Zeit. anorg . Chem., 1908, 6o, p . 178) obtained a greyish green powder of composition NiO2•xH2O, by adding an alcoholic solution of potassium hydrate to nickel-chloride and hydrogen peroxide at -5o° . It has all the reactions of hydrogen peroxide, and S . Tanatar (Bee., 1909, 42, p .

1516) regards it as NiO•H2O2 . An oxide, Ni304, has been obtained by heating nickel chloride in a current of moist oxygen at about 400" C . (H . Baubigny, Comptes rendus, 1878, 87, p . 1082), or by heating the sesquioxide in hydrogen at 19o° C . (H . Moissan, Ann . Chim . Phys., 1890 [5], 21, p . 199) . The former method yields greyish, metallic-looking, microscopic crystals, the latter a

grey amorphous powder . A hydrated form, Ni304.2H20, is obtained when the monoxide is fused with sodium peroxide at a red heat and the fused mass extracted with water .

Nickel Salts.—Only one

series of salts is known, namely those corresponding to the monoxide . In the anhydrous state they are usually of a yellow colour, whilst in the hydrated condition they are green . They may be recognized by the brownish violet colour they impart to a borax bead when heated in an oxidizing flame . The caustic alkalis added to solutions of nickel salts give a pale green precipitate of the hydroxide, insoluble in excess of the precipitant . This latter reaction is hindered by the presence of many organic acids (tartaric acid, citric acid, &c.) . Potassium cyanide gives a greenish yellow precipitate of nickel cyanide, Ni(CN)2, soluble in excess of potassium cyanide, forming a double salt, Ni(CN)2.2KCN, which remains unaltered when boiled with excess of potassium cyanide in presence of air (cf . COBALT) . Ammonium sulphide precipitates black nickel sulphide, which is somewhat soluble in excess of the precipitate (especially if yellow ammonium sulphide be used), forming a dark-coloured solution . Ammonium hydroxide gives a green precipitate of the hydroxide, soluble in excess of ammonia, forming a blue solution . Numerous methods have been devised for the separation of nickel and cobalt, the more important of which are : —the cobaltinitrite method by which the cobalt is precipitated in the presence of acetic acid by means of potassium nitrite (the alkaline earth metals must not be present); the cyanide method (J. v . Liebig, Ann., 1848, 65, p . 244 ; 1853, 87, p.128), in which the two metals are precipitated by excess of potassium cyanide in alkaline solution, bromine being afterwards added and the solution warmed, when the nickel is precipitated .

The latter method has been modified by adding potassium cyanide in slight excess to the solution of the mixed salts, heating for some time and then adding mercuric oxide and water, the whole being then warmed on the water

bath, when a precipitate of mercuric oxide and nickel hydroxide is obtained of the matte see Christofle and Bouilhet, French Patent 111591 (1876) . L . Mond (Jour . Soc . Chem . Ind . 1895, p . 945) has obtained metallic nickel from the Canadian mattes by first roasting them and then eliminating copper by the action of sulphuric acid, the product so obtained being then exposed to the reducing action of producer gas at about 3500 C . The reduced metal is then passed into a " volatilizer " and exposed to the action of carbon monoxide at about 8o° C., the nickel carbonyl so formed being received in a chamber heated to 18o-zoo° C., where it decomposes, the nickel being deposited and the carbon monoxide returned to the volatilizer . For an electrolytic method of treating mattes, see T. hike, Atoniteur scient., 1897, 49, p . 450 . The metal as obtained by industrial methods rarely contains more than about 99-99.5% of nickel, the chief impurities being copper, iron, cobalt, silicon and carbon .

The following tables show the output of nickel from Canada and the shipments of nickel ore from New Caledonia in recent years: CANADA

Production Export Production Export (lb) . ( ) . (lb) . (lb) .