Chemistry For Us: Industrial Inorganic Chemistry

Showing posts with label Industrial Inorganic Chemistry. Show all posts

Monday, 4 January 2021

IGCSE CHEMISTRY - IRON EXTRACTION

Iron Extraction

Iron is one of most common metals in the Earth's crust. Its ore is called haematite which mainly contains iron (iii) oxide, Fe2O3. It usually contains at least 60% iron.

Metals toward the middle of the reactivity series, such as iron and zinc are extracted in the blast furnace by reducing their ores with carbon since carbon is more reactive than iron/zinc.

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1. Complete the sentences using the words below.

Air blast calcium coke decomposes impurities slag Haematite oxide reduces air

We extract iron from iron ore in a …………….. furnace. The commonest ore of iron is ………………..

The other raw materials used are …………………,limestobe and coke.

The carbon monoxide is formed when ……………………… burns in a blast of ……….

Inside the blast furnace, carbon monoxide ……………………. Iron(iii) ……………. to iron.

The limestone added to the blast furnace …………………….. to form …………………….. oxide. Calcium oxide combines with the …………………….. in the iron ore to form ………………….

2. Complete the following labels for the diagram of the blast furnace for extracting iron. The labels fit in places A–F on the diagram.

molten iron out 1500 °C hot gases out blast of hot air in

mixture of iron ore, coke and limestone in molten slag out

A = …………………………………………….. B = ……………………………………………..

C = …………………………………………….. D = ……………………………………………..

E = …………………………………………….. F = ……………………………………………..

3. Write balanced chemical equations for these reactions which occur in the blast furnace.

a Carbon and oxygen react to form carbon dioxide.

……………………………………………………………………………………………………………

b Carbon dioxide reacts with carbon to form carbon monoxide.

……………………………………………………………………………………………………………

c Hematite (iron(iii) oxide) reacts with carbon monoxide to form iron and carbon dioxide.

……………………………………………………………………………………………………………

d Limestone (calcium carbonate) decomposes to form calcium oxide and carbon dioxide.

……………………………………………………………………………………………………………

e Calcium oxide reacts with impurities such as silica to form slag (calcium silicate).

……………………………………………………………………………………………………………

Tuesday, 21 November 2017

Iron Extraction-IGCSE CHEMISTRY

Industrial Inorganic Chemistry 10:41

Iron is only a moderately reactive metal - but it is less reactive than Carbon.

Because of this is can be smelted - displaced from Iron compounds by heating with Carbon (coke).

Iron compounds are found in rocks - we call rocks with high percentages of Iron compounds Iron ore.

The best known Iron ore is called Haematite (Haem - means Iron, as in Haemoglobin)

It contains Iron Oxide and many impurities.

It is dropped into the top of a blast-furnace along with Coke (purified Coal, almost pure Carbon) and Limestone (Calcium Carbonate).

Hot air is blasted in from the side to provide Oxygen that allows some of the Carbon to burn, releasing enough heat to raise the temperature above 1500^oC.

Carbon + Oxygen --> Carbon Dioxide

C_(s) + O_2(g) --> CO_2(g)

However, not enough Oxygen is added for complete combustion so some Carbon Monoxide is made.

Carbon Dioxide + Carbon --> Carbon Monoxide

CO_2(g) + C _(s)--> 2 CO_(g)

Carbon Monoxide is toxic but its presence in the Blast Furnace is important to how the process works because it removes Oxygen from (Reduces) the Iron Oxide to Iron.

Carbon Monoxide + Iron Oxide --> Iron + Carbon Dioxide.

3 CO_(g)+ Fe₂O₃ _(s) --> 2 Fe _(l) + 3 CO_2(g)

_{The Iron is dense and liquid and so flows to the bottom of the furnace.}

_{The Carbon Dioxide escapes at the top.}

_{If the impurities in the Iron Ore were allowed to mix in with the Iron it would be brittle and useless.}

_{But the Limestone breaks down (thermally decomposes) to form Lime which then reacts with the sandy impurities}

_{Calcium Carbonate (Limestone) --> Calcium Oxide (Lime) + Carbon Dioxide}

_{CaCO_{3 (s)} --> CaO _(s) +}_CO2(g)

_{Calcium Oxide + Silicon Oxide (sandy impurities) --> Calcium Silicate (Slag)}

CaO _(s)₊SiO_2(s) --> CaSiO_3(l)

_{The slag also flows to the bottom of the furnace but is less dense than the Iron and so floats on top, allowing them both to be tapped off separately.}

_source:https://sites.google.com/site/internationalgcsechemistry/year-10-topics/extraction-and-uses-of-metals/3---extracting-iron