How is Iron Extracted?

In China, raw iron ore is used to make iron directly, so how is iron extracted? The early method is to make iron by block, and later by shaft furnace. In the late spring and Autumn period, liquid pig iron that can be cast has been made and cast into ironware and applied to production. Besides, cast the iron softening was invented, which accelerated the historical process of ironware replacing copperware and other production tools.

How is iron extracted:

1. Raw materials for iron making: raw iron ore, coke, limestone, and air

A. Iron ore: mainly hematite Fe2O3, magnetite Fe3O4, siderite FeCO3, pyrite FeS2

B. Coke: the main function is to provide heat and produce reducing agent Co;

C. Limestone: it is mainly used for slagging and removing SiO2 and other impurities in iron ore

2. Ironmaking equipment: blast furnace

3. Principle of ironmaking: under high temperature, the natural iron ore is reduced from iron oxide by carbon monoxide

4. Ironmaking process and reaction (taking hematite as an example):

A. Coke burns to produce heat and reductant

C + O2 ignition = = = CO2; CO2 + C  high temperature = = = 2CO
B. Reduction of iron oxide by CO to iron Fe2O3 + 3Co  high temperature = = = 2Fe + 3co2

C. Cao produced by the decomposition of SiO2 and CaCO3 reacts to form calcium silicate

CaCO3 high temperature = = = CaO + CO2 ↑;

CaO+SiO2==CaSiO3 (main components of slag)

5. Ironmaking products: raw iron ore (mainly Fe, C alloy), filter slag (mainly CaSiO3), blast furnace gas (mainly CO)

According to the calculation of chemical formula, the mass fraction of pyrite and siderite is small, and pyrite contains the sulfur element. In the process of ironmaking, it is likely to form sulfur dioxide gas, which will be discharged into the air and cause air pollution

6. Metal smelting method:

A. Reduction method: heating reaction of metal minerals with reducing substances such as coke, hydrogen, carbon monoxide, etc

For example, copper Cu2O + C is extracted from hematite (Cu2O) at high temperature = = = 2Cu + CO;

Ancient copper hydrometallurgy: Fe + CuSO4 = = FeSO4 + Cu

B. Electrolysis: it is difficult for active metals to be reduced from their ores. Electrolysis is needed.

For example: electrolytic melting of alumina to produce aluminum: 2al2o3 electrified = = = 4Al + 3O2 ↑; electrolytic melting of sodium chloride to produce sodium: 2nacl electrified = = = 2Na + Cl2 ↑

C. Decomposition: some metal oxides are easy to decompose when heated, and can be obtained by simple heating

For example: mercury oxide to mercury: 2hgo high temperature = = = 2hg + O2 ↑