What Is Non-ferrous metals?
Non-ferrous metals are alloys or alloys that contain no amount of iron. All pure metals, except iron (Fe), are non-ferrous elements, also called ferrite, from the Latin forum, meaning “iron”.
Non-ferrous metals are more expensive than ferrous metals but are used for their desirable properties, such as low weight (aluminium), high conductivity (copper), non-magnetic properties, or resistance to corrosion (zinc). Some non-ferrous materials are used in the iron and steel industries, such as bauxite, which is used for flow in blast furnaces. Other non-ferrous metals, including chromite, pyrolusite and wolframite, are used to make ferrous alloys. However, many non-ferrous metals have low melting points, making them less suitable for applications at higher temperatures.
Following Are The Types Of Non-ferrous Metals
I. Aluminium:
Aluminium occurs in abundance on the earth’s surface. This is available in various forms such as oxides, sulphates, silicates, phosphates, etc. But it is commercially produced mainly from bauxite (Al 20 3, 2H20) a hydrated oxide of aluminium.
Manufacture:
Aluminium is the extracted from bauxite ores as follows:
(I) Bauxite is purified.
(2) It is then dissolved in fused cryolite which is a double fluoride of aluminium and sodium, AlF 3, 3NaF.
(3) This solution is then taken to an electric furnace and aluminium is separated out by electrolysis.
Properties:
Following are the properties of aluminium:
( l) It is a good conductor of heat and electricity.
(2) It is a white metal with a bluish tinge.
(3) It is rarely attacked by nitric acid, organic acid or water. It is highly resistant to corrosion.
(4) It is light in weight, malleable and ductile.
(5) It melts at about 658°C.
(6) It possesses great toughness and also tensile strength.
(7) It readily dissolves in hydrochloric acid.
(8) Its specific gravity is about 2·70.
Uses:
This metal is chiefly used for making parts of aeroplane, utensils, paints, electric wires, window frames, glazing bars, corrugated sheets, structural members, foils, posts, panels, balustrades, etc. After the second world war, this material has been tried for structural members.
Its use as a structural material is therefore very recent. But it has made good progress during this period and research is going on to make maximum use of this metal as a structural material. Following are some of the illustrations to support the above fact:
( 1) In England, an exhibition was held in 1951. At this exhibition, a corner of aluminium, known as ‘Dome of Discovery’ was also installed. The diameter of the dome was about 103 m. Such domes can be used to cover small reservoirs.
(2) Movable bridges of aluminium are made in New Zealand. Such bridges are extremely useful in case of an emergency.
(3) A girder of aluminium is made for a godown in England. The span of this girder is about 62 m.
( 4) In many countries of the world, foot-bridges of aluminium are made and these are working quite satisfactorily.
(5) In Germany, a bridge of aluminium is made. Its span is about 44 m and its total width, including projections of footpaths of width 45 cm on either side, is 4·35.
(6) Aluminium has also been successfully tried for movable constructions such as cranes, movable bridges, etc.
(7) A gigantic aerodrome has been prepared from aluminium in England. Portal frames with a span of about 65 m are adopted in the design of this aerodrome.
Had these frames been made from steel, their weight would have been about seven times more than that of aluminium frames. It is thus seen that aluminium has been receiving more attention for its use as a structural material.
It is quite likely, therefore, that in near future, aluminium may secure, a distinct place among structural materials.
II. Cobalt:
Cobalt is found to occur in a free state in meteorites. Its two important ores are arsenide and sulphocyanide.
Manufacture:
The ores are purified and are then fused with limestone or sand in a blast furnace. It gives impure oxide of cobalt. Impurities from this oxide of cobalt are removed by various wet processes.
Properties:
Following are the properties of cobalt:
(I) If cobalt is red hot, it can decompose steam.
(2) If it is in a finely ground powder form, it may absorb hydrogen to the extent of about 150 times its volume.
(3) It is a lustrous white metal.
( 4) It is magnetic and can retain its magnetic properties up to a temperature of about 1100c.
(5) It is malleable and ductile.
(6) It is not affected by the atmosphere at ordinary temperature.
(7) It is not attacked by alkalies.
(8) Its specific gravity is 8·80.
Uses:
Cobalt is more used in the preparation of special alloy steels, ceramic products, television articles, etc.
III. Copper:
Copper is found in practically all major countries of the world. Its main ores are Cuprite Cu2O, Copper Glance Cu2S, Copper Pyrite CuFeS2, Malachite CuCO3 · Cu (OH) 2 and Azurite 2CuCO3 · Cu (OH) 2
Manufacture:
Copper is manufactured by a laborious method and the treatment to be adopted depends largely on the quality of the copper ore. The general outline of the modern process of copper making is as follows:
( 1) The ores, usually pyrite, are crushed and then counted in the resonant furnace.
(2) The calcined ores are mixed with silica and a small quantity of coke. The mixture is then smelted in a blast furnace.
(3) The melted metal is oxidised in the Bessemer converter. It gives blister copper.
(4) Impurities contained in blister copper are removed by melting it in a reverberatory furnace in presence of air.
( 5) Slag is removed and pure copper to the extent of about 99·70% is obtained.
(6) Very pure copper or 100% copper is obtained by the process of electrolysis.
Properties:
Following are the properties of copper:
( 1) It becomes brittle just below its melting point.
(2) It can be worked in hot or cold conditions. But it cannot be welded.
(3) It has a peculiar red colour.
(4) This is a good conductor of heat and electricity.
(5) It is attacked by steam at white heat.
( 6) It is not attacked by dry air, but moist air gives the green coating to the copper surface.
( 7) It is not attacked by water at any temperature.
(8) It is malleable, ductile and soft.
(9) It melts at 1083°C.
(10) Its specific gravity is 8·90.
Uses:
In non-ferrous metals, the copper market forms are ingots, sheets, pipes and wires. It is widely used to manufacture electrical cables, alloys, household utensils, electroplating, lighting conductors, stone masonry dowels, etc.
IV. Lead:
Lead occurs occasionally in a free state in nature. In combined form, it mainly occurs as sulphide, ore being known as Galena, PBS. This is the important and widely distributed ore of kad.
Manufacture:
Lead is extracted from galena ores is as follows:
( l)The ores are concentrated.
(2)Coke and metallic iron are added to ores.
(3)The mixture is then smelted in a blast furnace.
( 4)Impure lead is obtained which is further purified in a reverberatory furnace.
Properties:
Following are the properties of lead:
( 1) It can be cut with a knife or resieor.
(2) It makes impression on paper.
(3) It melts at 326°C.
(4) It is a lustrous metal with bluish-grey colour.
(5) When strongly heated in the presence of air or oxygen, it is converted to lithargy.
(6) It is not invaded by dry air, but moist air takes on its bright metallic glow.
(7) It possesses little tenacity.
(8) It is soft.
(9) Its specific gravity is 11 ·36.
Uses:
Lead is widely used for making shots, bullets, alloys, storage cells, sanitary fittings, cisterns, waterproof and acid-proof chambers, gas pipes, roof gutters, printing types, dampproof courses of buildings, cable coverings, preparation of lead oxides for paints, etc.
V. Magnesium:
Magnesium does not occur in a free state in nature. Its principal ores are magnesite MgCO3 , dolomite CaCO3, MgCO3, kieserite MgSO4, H2O and carnallite- MgC1 2, KCI, 6H2O.
Manufacture:
For obtaining magnesium on a small scale, anhydrous magnesium chloric is heated with sodium in presence of coal gas. For large scale production, magnesium is obtained by the electrolysis of carn all etc.
Properties:
Following are the properties of magnesium:
( 1) It burns with a dazzling white light when heated Ill atr.
(2) It carries away heat easily.
(3) If it is in the form of finely divided particles, it burns readily and easily.
(4) If highly heated, it can decompose steam.
(5) It is a silver-white metal.
(6) It is ductile and malleable.
(7) It is not affected by alkalies.
(8) Its melting point is 651 °C.
(9) Its thermal coefficient of expansion is more.
Uses:
Magnesium is used in photography, fireworks, signaling, etc. It cannot be used solely for constructive work. But some of its alloys can be used for some structural parts.
VI. Nickel:
The meteorite is found in a nickel-free state. In combination, this occurs mainly as sulfide ores and silicate ores.
Manufacture:
Nickel is extracted from sulphide ores is as follows:
( 1) They ores are cleaned of earthy matter.
(2) They are roasted in heaps.
(3) The roasted ores are smelted in a blast furnace along with limestone, quartz and coke.
(4) The molten mixture of nickel and copper sulphide collects at the bottom. It is led to a Bessemer converter with basic lining.
(5) After treatment in a converter, metallic nickel 1s are obtained by repeated smiting and electrolysis.
Properties:
Following are the properties of nickel:
(1)If nickel is red hot, it decomposes the steam.
(2)If it is in finely ground powder, it can absorb hydrogen approximately 17 times its volume.
(3)It is a greyish-white lustrous metal.
(4)It is capable of taking a high polish.
(5)It is fairly resistant to the actions of the atmosphere and it becomes dull after a long time.
(6)It is hard, malleable and magnetic
(7)It is not attacked by fused alkalies.
(8)Its corrosion resistance is high.
(9)Its specific gravity is 8·90.
Uses:
Nickel is widely used as a coating for other metals and the preparation of alloys.
VII. Tin:
Tin occurs chiefly as tinstone or cassiterite which is its oxide, SnO2 It is also available in nodules which are known as stream tin.
Manufacture:
Tin is extracted from its ore as follows:
( 1) The ore is crushed and washed to remove impurities.
(2) It is then calcined in a revolving calcined.
(3) The calcined ore is allowed to cool.
( 4·) After cooling it is rinsed with water.
( 5) The liquid is allowed to rest. Processed tinstone collects at the bottom because it is heavy.
(6) It is then smelted in a furnace with anthracite coal and sand.
(7) It is finely refined in a reverberatory furnace to obtain commercially pure tin.
Properties:
Following are the properties of tin:
( 1) If the tin strap is bent, a bizarre noise occurs, sometimes called a tin cry.
(2) It becomes brittle when heated to a temperature of about 200°C.
(3) It melts at 232°C.
( 4) It is a white metal with a brilliant lustre.
(5) It is not affected by dry air.
(6) It is not attacked by pure water.
(7) It is soft and malleable.
(8) Its specific gravity is 7·30.
Uses:
Tin is used for preparing alloys, utensils or vessels for household and technical use tin-foils, etc. It is also used for giving a protective coating to other metals.
VIII. Zinc:
Zinc does not occur in a free state in nature. Its principal ores are zincite ZnO, franklinite ZnO, Fe203, calamine ZinC and zinc blende ZnS.
Manufacture:
Zincate- or zinc oxide is heated in Zinc is liberated in the form of vapour. condt>nosed to get mt>tallic zinc.
Properties:
an electric furnace. This vapour is then Following are the properties of zinc:
( 1) It burns with a greenish-white flame when strongly heated in the air.
(2) It may be drawn into wires and rolled into sheets between the temperature range of l00°C to 50°C.
(3) It melts at 419°C.
( 4) It is a bluish-white metal.
(5) It is brittle at the ordinary temperature.
(6) It is not affected by dry air.
(7) It is not invaded by pure water.
(8) Its specific gravity is 6·86.
Uses:
Zinc is used in electric cells, for galvanising, in the preparation of alloys, paints, etc.
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