Below are the distinguishing points between metals and non-metals

MetalsNon-MetalsThese are solid at room temperature and have lustre.These are either gases or soft solids and do not possess lustre.They are good conductors of electricity except for Tungsten.They are bad conductors of electricity except for carbon and graphite.They have high melting and boiling points and have high density.They have low melting and boiling points and are less dense.They have valence electrons 1, 2, or 3.They have valence electrons 4 to 7.They lose electrons and are reducing agents.They gain electrons and are oxidising agents.They release hydrogen when diluting with acids.They do not release hydrogen when diluting with acids.

Metals exist in nature in impure form. The crust of the earth is the main source of metal. Metals exist both in combined form or in the free state. Gold and mercury are available in the free state. Sodium and magnesium are present as chlorides. The metals present in a combined state are called minerals.

Metals are present inside the earth in impure form. They need to be extracted and transformed into pure form. Metallurgy is the process of extraction of metals from the ore in pure form. The metals, when extracted from ore, have soil, sand, rock, and limestone combined. These limestone, rock, and salt are called ores. The impurities that get removed during the process of metallurgy are called flux.

Metallurgy follows the below steps:

Step1: Concentration of Ore

In this step, the matrix gets separated from the ore. This step uses the below principles of extraction.

1. Magnetic separation: This method is mainly applicable for the ores of aluminium and iron. For these two metals, either the ore or matrix is magnetic, and the other is non-magnetic.
2. Froth floatation method: In this method, the ore gets wetted with oil. As a result, the impurities get wet with water, and impurities settle at the base.
3. Hydrolytic method: This method works by the different densities of metal and impurities. The sense particles settle at the bottom, and lighter ones get washed with water.
4. Chemical method: In this method, flux gets added into impure ore so that matrix gets separated.

Step2: Ore conversion to metal oxide

In this step, the concentrated ore gets converted into metal oxides using one of the below methods:

1. Calcination: Concentrated ore is heated in the absence of air or in limited air.
2. Roasting: Concentrated ore gets heated in the presence of air.

Step3: Reduction of metallic oxides to metal

In this step, the metal oxide gets reduced to metals. It is done using the process of electrolysis or with the help of reducing the agents.

Step4: Refining

In this step, the impure metal gets refined to get pure metal. Below methods are used for refining:

1. Liquidation refining: It is used for the refining of lead and tin.
2. Distillation refining: It is used for the refining of mercury and zinc.
3. Oxidation refining: It is used for the refining of iron.
4. Electro-refining: It is used for the refining of copper and aluminium.

Aluminium ore, also called bauxite, follows the metallurgy process for the extraction of aluminium. Below steps are followed to extract aluminium from bauxite.

Step1: Baeyer’s process

This is the step of concentration of aluminium ore called bauxite. It is the chemical method in which aluminium oxide is treated with sodium hydroxide. As a result, sodium aluminate is formed, which is soluble and can be filtered. The filtrate then gets heated with water that forms aluminium hydroxide crystals. Aluminium hydroxide is heated strongly to form alumina.

Step2: Hall Heroult’s Process

Hall Heroult’s process is the method of extraction of aluminium. It is the process of electrolytic extraction in which Na3AlF6 or CaF2 gets mixed with alumina (Al2O3). It helps in reducing the melting point and makes it conduct electricity. This process is followed in the steel vessel having carbon lining and graphite rods immersed in the vessel. The carbon lining of the vessel acts as a cathode, and the graphite rods act as an anode. When electricity is passed, oxygen forms at the anode. Oxygen released at anode combines with carbon to form carbon dioxide and carbon monoxide. Aluminium ions get accumulated at the cathode and then settle at the bottom.

The aluminium collected by Hall Heroult’s process is almost 99.5% pure.

1. Aluminium foil is used for food wrapping purposes.
2. It has a wide variety of applications in the transport and construction fields.
3. It can easily be moulded into different shapes and used to form storage cans.
4. It is the most used metal after iron.
5. Dust of aluminium is added to paints.
6. It helps in the extraction of chromium and manganese.

To conclude, metals are the elements that ionise to form positive ions. The occurrence of metals in nature is a free or combined state. The metals present in the combined state have to go through the process of metallurgy to get extracted as refined in pure form.

1. What are the methods to prevent corrosion?
2. Two methods to prevent corrosion are galvanisation and painting.
3. What is the name of Aluminium ore?
4. Bauxite is an aluminium ore.
5. What is Baeyer’s process?
6. Baeyer’s process is the extraction of alumina from bauxite by adding concentrated sodium hydroxide.
7. What is Hall Heroult’s process?
8. Hall Heroult’s process is the method of extracting pure aluminium from alumina using electrolysis.
9. What are metals?
10. Metals are the elements that ionise by losing electrons.
11. How are metals different from non-metals?
12. Metals lose electrons and form positive ions, while non-metals gain electrons and form negative ions.