Chemistry In Industry

Extracting Iron: Choose the CORRECT 3 Raw Materials used in the Blast Furnace...

Iron is extracted from [blank_start]haematite[blank_end] by [blank_start]reduction[blank_end] (i.e. the removal of [blank_start]oxygen[blank_end]) in a blast furnace.

Hot air is blasted into the furnace, making the coke burn much faster than usual. The coke burns and produces carbon dioxide: C + O2 ---> CO2 Carbon + Oxygen ---> Carbon Dioxide

Hot air is blasted into the furnace making the coke burn much faster than normal. This raises the temperature to about [blank_start]1500[blank_end] degrees celsius.

The carbon dioxide then reacts with unburnt coke to form carbon monoxide. CO2 + C --> ?

The carbon monoxide then reduces the iron ore to iron. This means the carbon monoxide is the [blank_start]reducing agent[blank_end]. The formula for this stage of the reaction is: 3CO + Fe2O3 --> 3CO2 + 2Fe Carbon monoxide + [blank_start]iron (iii) oxide[blank_end] --> Carbon dioxide + [blank_start]Iron[blank_end]

After the carbon monoxide has reduced the iron (iii) oxide to iron the iron is molten at this temperature and it's also very dense, so it runs straight to the bottom of the furnace where it's tapped off. In the furnace which sits on top of the other is it the molten iron or the molten slag?

The main impurity is [blank_start]sand[blank_end] (silicon dioxide). This is still [blank_start]solid[blank_end], even at 1500 degrees and would tend to stay mixed in with the iron. The [blank_start]limestone[blank_end] removes it.

The limestone is decomposed by heat into calcium oxide and CO2. CaCO3 ---> CaO + CO2 (Thermal Decomposition.)

The calcium oxide then reacts with sand to form [blank_start]calcium silicate[blank_end], or slag which is molten (less dense than molten iron) and can also be tapped off. CaO+SiO2 --> [blank_start]CaSiO3[blank_end] (molten slag)

This cooled slag is solid and is used for: (choose the 2 correct uses)

The iron ore contains the [blank_start]iron[blank_end]. The coke is almost [blank_start]pure carbon[blank_end]. This is for [blank_start]reducing[blank_end] the iron oxide to iron metal. The [blank_start]limestone[blank_end] takes away impurities in the form of slag.

Uses of Iron and Aluminium: Iron and Aluminium have some properties in common. 1) They are both dense and [blank_start]lustrous[blank_end] (shiny) 2) They have [blank_start]high melting points[blank_end] - Iron melts at 1538 and aluminium melts at 660. 3) They both have [blank_start]high tensile strength[blank_end] - they're strong and hard to break. 4) Can also be hammered into different shapes. [blank_start]Malleable[blank_end]. 5) They are both [blank_start]good conductors[blank_end] of electricity and [blank_start]heat energy[blank_end] too.

The uses of iron depend on its properties: 1) Wrought iron - is almost completely [blank_start]pure iron[blank_end]. It's [blank_start]malleable[blank_end] so it's used to make ornamental gates and railings. You can mix iron with other elements to make [blank_start]alloys[blank_end]. E.g. 1) Cast iron: Mixture of iron, carbon and silicon. Hard, brittle and is used for [blank_start]manhole covers and some cooking pans[blank_end]. 2) Steel: Alloy made or iron, carbon and usually some other metals. Harder than pure iron but can still be hammered into sheets and welded together. These properties mean that steel is great for [blank_start]making car bodies and girders[blank_end] (for construction.) Main problem is iron corrodes easily. E.g. It [blank_start]rusts.[blank_end] [blank_start]Stainless steel[blank_end] is an alloy made of iron and chromium that doesn't rust. Used for knives and forks and cooking pans.

Uses of Aluminium: Unlike iron doesn't [blank_start]corrode[blank_end] easily. Reacts very quickly with the [blank_start]oxygen[blank_end] in the air to form aluminium oxide. Because Aluminium doesn't corrode useful for products that come into contact with water. E.g. [blank_start]drink cans.[blank_end] Aluminium is much [blank_start]less dense than iron[blank_end], which makes it lighter so used for bicycle frames and [blank_start]aeroplanes.[blank_end]