Extraction of metals Unit 9

reaction for formation of slag

CaO(s) + SiO2(s) —> CaSiO3 (l)

the order of extracting iron from hematite (reactions)

-burning of coke to form co2

-reduction of co2 to co

-reduction of hematite by co

-thermal decomposition of limestone

-formation of slag

reduction of co2 reaction

CO2(g) + C(s) —> 2CO(g)

reduction of hematite by co

Fe2O3(s) + 3CO(g) —> 2Fe(l) + 3CO2(g)

thermal decomposition of limestone

CaCO3(s)—> CaO(s) +CO2 (g)

explain the electrolysis of bauxite

-Molten cryolite is added (dissolved in bauxite) as it has a lower melting point than aluminium oxide, so it reduces the amount of heat & energy needed, as well as cost

-Carbon anodes need to be regularly replaced because the carbon reacts with oxygen molecules to form carbon dioxide

-at the cathode: forms pure molten aluminium

-at the anode: forms oxygen gas

what is added to the blast furnace in order to extract iron from hematite

coke, air, limestone and hematite

why is limestone used in the blast furnace

to remove any acidic impurities from the iron

what is in steel

iron mostly and nickel

what is in brass

copper and zinc