Question

Write the Classification of extraction of metals?

Answer 1

The classification of extraction of metals is know as metaluragy

Answer 2

Physical Properties:

Metals are hard, non-adhesive, cold and smooth,they are very often shiny and strong. They are also ductille and malleable, do not break easily. Metals are very good conductors of electricity, sound and heat. When temperature rises they expand, and when it falls, they always contract. They can be easily welded to other metals.

Chemical Properties:

Metals react with oxygen in water and air. It's known as oxidation or rusting and it's a reddish- or yellowish-brown flaky coating of iron oxide that is formed on iron or steel, especially in the presence of moisture.

Ecological Properties:

Most metal are recyclable and some metals such as lead or mercury are toxic and they are a danger for humans being and for  the enviroment.

Extraction of metals

There are two types of mines to obtain metals:

Surface mining that is used when the mineral is near the surface.Underground mining that is used when the mineral is deep below the surface.

It's used excavators, drills, explosives for extracting minerals from the rock.The minerals are separated into ore and gangue.

Classification of metals

 Metals can be divided into two main groups: ferrous metals are those which contain iron and non-ferrous metals that are those which contain no iron.

Ferrous Metals

Pure Iron is of little use as an engineering material because it is too soft and ductile. When iron cools and changes from a liquid to a solid, most of the atoms in the metal pack, tightly together in orderly layers. Some, however. become misaligned, creating areas of weaknesses called dislocations. When a piece of iron is put under stress, layers of atoms in these areas slip over one another and the metal deforms. This begins to explain the ductility of soft iron. By adding carbon to the iron however, we can produce a range of alloys with quite different properties. We call these the carbon steels. An alloy is a mixture of two or more chemical elements and the primary element is a metal.

Carbon Steels: their properties and uses

Mild Steel: carbon content between 0,1% and 0,3%. Properties: less ductile but harder and tougher than iron, grey colour, corrodes easily. Uses: girders or beams, screws, nut and bolts, nails, scaffolding, car bodies, storage units, oil drums.

Medium carbon steel contains between 0,3% and 0,7% carbon. Properties: harder and less ductile than mild steel, tough and have a high tensile strength. Uses: it's used for the manufacture of products which have to be tough and hard wearing like gears, tools, keys, etc

High carbon steel contains between 0,7% and 1,3% carbon. Properties: Very hard and brittle material. Uses: It's used for cutting tools and products which have to withstand wear such as guillotine, springs, etc.

Stainless steel are iron and chromium alloys. A wide range of steels are available with chromium content between 13% and 27%. Properties: Chromium prevents rusting with an oxide film. Ductility, hardness and