Refining process that occurs in a blast furnace?

Answer 1

The refining process is actually a REDUCTION process.

The iron ore ( oxidised iron ) is reduced in the Blast Furnace to IRON.

Three substances are mixed and added to the Blast Furnace.

They are Iron Ore (Iron(III) Oxide ; Fe2O3)

Coke (Carbon ; C)

Limestone ( Calcium carbonate ; CaCO3)

A Blast of Hot Air is sent in from the bottom (O2)

The heat makes the limestone decompose to calcium oxide(CaO) and carbon dioxide(CO2)

The Carbon then reacts with the carbon dioxide and also the air to form carbon monoxide.

CO2 + C = 2CO & "C + O2 = 2CO (4CO)

It is the Carbon Monoxide (CO) that reacts with iron ore to form iron. as carbon monoxide is a powerful reducing agent.

2Fe2O3 + 4CO = 4Fe + 4CO2 (Not Balanced)

As a secondary reaction the calcium oxide reacts with the impurities in the iron oxide (viz. sand ; SiO2) to form 'slag' (calcium silicate) .

CaO + SiO2 = CaSiO3 (slag).

Calcium silicate is used top make road surfaces, and 'breeze' blocks for building.

The iron that is collected is still impure, and whilst liquid hot, is placed in a BOS plant with an oxygen lance, to oxidise any remaining impurities, viz. sulphur, (to sulphur dioxide) and phosphorus(to Phosphorus oxide). The carbon impurity ( to carbon dioxide) is controlled at this stage in order to make steel , which contains about 0.1% to 2% carbon , depending on the nature of the steel.

Answer 2

Smelting