Ore Most elements exist as compounds . With Oxygen (M X O Y )or with sulphur

1. OreMost elements exist as compounds. With Oxygen (MXOY)or with sulphur Ores https://www.youtube.com/watch?v=fZM_NF93gWo

2. Metals in Nature Metals can be found in nature: 1) -Free Ex: silver, gold, copper, platinum, nickel. 2) -Slave or combined in the form of ores . All other metals. • Free the Slave • The metal from O or S • the metal ion must be split • Away. • Ways to free the Metal • Electrolysis • React it with reducing agent • Heat (melt) the metal out

3. How does reactivity affect extraction? The reactivity of a metal determines how it is extracted. Metals above carbon in the reactivity series must be extracted using electrolysis. Electrolysis can also be used to purify copper. potassium increasing reactivity sodium calcium magnesium aluminium (carbon) Metals less reactive than carbon can be extracted from their ores by reduction using carbon, coke or charcoal. zinc iron lead (hydrogen) copper Platinum, gold, silver and copper can occur nativeanddo not need to be extracted. silver gold platinum

4. Which metals does carbon reduce? A metal can be reduced by carbon if it is less reactive than carbon and so appears below carbon in the reactivity series. potassium sodium calcium magnesium aluminium Certain metals, such as iron, can be only be reduced using carbon if they are heated to very high temperatures. (carbon) zinc iron If a metal is more reactive than carbon, other chemical reactions and processes must be used in its extraction. lead (hydrogen) copper silver gold platinum

5. ALUMINIUM Electrolysis

6. ELECTROLYSIS Electricity Lyse/lysis meaning “to move” For electrolysis we need a system we can pass electricity through. • SOLID IONIC COMPOUNDS DON’T CONDUCT ELECTRICITY • Why? • BECAUSE THE IONS ARE NOT FREE TO MOVE, so what do we do? • DISSOLVING IN WATER or • MELTING ALLOWS THE IONS TO MOVE FREELY Al and Electrolysis https://www.youtube.com/watch?v=87K8QsMl8nc

7. Potassium Sodium Calcium Magnesium Aluminium Zinc Copper Silver Gold K Na Ca Mg Al Zn Cu Ag Au The Reactivity Series. Reactive ALKALI’s Metals high up on the series are strongly bonded in their compounds. Electrolysis is the only method strong enough to extract these. Kanadian Named Carrie Married Al Zebra (in a) cupola of silver and gold

8. Aluminium Ore BAUXITE Bauxite is not a single composition, more a range of hydrated aluminium oxides and hydroxides.

9. The chemistry of bauxite processing Aluminum: The choice of presidentsNapoleon III, the first President of the French Republic, served his state dinners on aluminum plates. Rank-and-file guests were served on dishes made with gold or silver. A bar of aluminium was even exhibited at the Paris Exhibition in 1855 as “the new precious metal” Why? Is it still considered a noble metal? Noble metals are resistant to corrosion. Ex: Rh, Pd, Ag, Pt, Au The complex mixture that makes up bauxite is first processed to produce pure aluminium oxide, alumina (Al2O3) So we need molten alumina to do electrolysis ……….at a temperature over 2072oC, the melting point of alumina. This is far too high for an economic process. Alumina is melted in another chemical, cryolite (Na3AlF6), which lowers the melting point to around 1000oC.

10. Keeping the electrolysis cell molten The energy to provide the initial melting is enormous so these run continuously for many years before finally being taken out of service. https://www.youtube.com/watch?v=mvDHeYI-a00

11. EXTRACTION OF ALUMINIUM ELECTRONS OXIDATION (LOSS OF ELECTRONS) TAKES PLACE AT THE ANODE CARBON ANODE LEOA 2 O2- O2 + 4e-OXIDATION at ANODE

12. EXTRACTION OF ALUMINIUM ELECTRONS OXIDATION (LOSS OF ELECTRONS) TAKES PLACE AT THE ANODE REDUCTION (GAIN OF ELECTRONS) TAKES PLACE AT THE CATHODE CARBON CATHODE GERC Al3+ + 3e- AlREDUCTION at CATHODE

13. EXTRACTION OF ALUMINIUM CARBON DIOXIDE PROBLEM THE CARBON ANODES REACT WITH THE OXYGEN TO PRODUCE CARBON DIOXIDE CARBON ANODE THE ANODES HAVE TO BE REPLACED AT REGULAR INTERVALS, THUS ADDING TO THE COST OF THE EXTRACTION PROCESS

14. PROPERTIES OF ALUMINIUM ALUMINIUM IS NOT ACTUALLY (in real life) AS REACTIVE AS ITS POSITION IN THE REACTIVITY SERIES SUGGESTS THIS IS BECAUSE A THIN LAYER OF ALUMINIUM OXIDE QUICKLY FORMS ON ITS SURFACE AND PREVENTS FURTHER REACTION TAKING PLACE THIN LAYER OF OXIDE ANODISINGPUTS ON A CONTROLLED LAYER SO THAT THE METAL CAN BE USED FOR HOUSEHOLD ITEMS SUCH AS PANS AND ELECTRICAL GOODS

15. ANODISING ALUMINIUM Aluminium is very unreactive for a metal so high up the reactivity series. This is due to the ease with which it forms a protective oxide layer. Anodising makes this oxide layer even stronger. Step 1. The original oxide layer is removed with sodium hydroxide. Step 2. The aluminium is made into the anode Step 3. Oxygen, evolved at the anode, reacts with the aluminium to form a 0.02mm oxide film. Much thicker than before anodising.

16. Uses of aluminium Aluminium is low density, strong, a good conductor of heat and good conductor of electricity. • Electricity cables along overhead wires. • Aircraft industry • 3. Pop cans

17. SODIUM Electrolysis

18. Electrolysis and the EXTRACTION OF SODIUM Involves electrolysis of molten sodium chloride in the Down’s Cell. CaCl2 is mixed with the sodium chloride to lower the melting point and reduce energy costs. Sodium is discharged at the cathodeNa+ + e¯ ——> Na Chlorine is discharged at the anodeCl¯ ——> ½Cl2 + e¯

20. Methods of metal extraction: • 1.Electrolyis: • Most powerful means of extraction. • Most expensive. • Can only be used where electricity is abundant. • 2. Reduction with carbon(carbon monoxide) • Cheaper to operate than electrolysis.

21. IRON Pyrometallurgy

22. Extraction of Iron • The Steel blast furnace lined with fire bricks at temperatures from up to 1900C. Fe2O3 + 3 CO  2 Fe(s) + 3 CO2 Reduction G.E.R. +3 0 Fe2O3 Fe (s) Oxidation L.E.O. +2 +4 CO  CO2(g)

23. gangue flux slag Smelting Pyrometallurgy(Fe Smelting by roasting) Heating a mineral to react with gases (CO(g)) is roasting • if the roast product is a liquid (Fe(l)) it’s called smelting The sand from the ore (SiO2) doesn’t volatilize, so a flux (CaCO3) is added to react with the nonvolatile gangue (junk) to create a low-melting waste product easy to separate • the waste liquid is called the slag • the slag floats on the molten metal by density

24. 3 Ingredients • Iron ore, Fe2O3, (and SiO2) • Limestone (CaCO3) • Coke (C ) are charged (loaded) The limestone decomposes to CO2 1) CaCO3CaO + CO2 2) C + O2  CO2 Coke is made from bituman (coal) heated without air to make a lot of C(s).

25. Reduction of Iron SO2 CO2 C + O2  CO2 Coke makes CO2 Start at the bottom. CO2+ C 2CO more coke makes The reducing agent CO Fe2O3 + 3 CO  2 Fe(s) + 3 CO2 The molten “pig” iron sinks to the Bottom and has many impurities, such as sulphur and silica which wasn’t removed by the limestone. C + O2  CO2 95% pure. calcium silicate (SLAG)

26. Cast Iron Contains 2%-4% of carbon Very hard but brittle Strong under compression Engine block, engineer vices, machine parts

27. SLAG PRODUCTION • silica (sand) is found with the iron ore • removed via a reaction with limestone EQUATIONS limestone decomposes on heating CaCO3 —> CaO + CO2 calcium oxide combines with silica CaO + SiO2 —> CaSiO3 overall CaCO3 + SiO2 —> CaSiO3 + CO2 Removes impurities : slag production • Lime decomposes CaCO3CaO + CO2

28. WASTE GASES AND POLLUTION SULPHURDIOXIDE and ACID RAIN • sulphur is found in the coke; sulphides occur in the iron ore • burning sulphur and sulphides S + O2 ——> SO2 produces sulphur dioxide •sulphur dioxide gives SO2 + H2O ——> H2SO3 rise to acid rain sulphurous acid CARBONDIOXIDE • burning fossil fuels increases the amount of this greenhouse gas

29. LIMITATIONS OF CARBON REDUCTION Theoretically, several other important metals can be extracted this way but are not because they combine with the carbon to form a carbide e.g. Titanium, Vanadium, Tungsten

30. Q & A • What is Limestone made of? • How are impurities from the ore removed? • What is the layer of precipitated impurities called? • Where does the carbon dioxide produced during the process come from? • What is the function of Coke during the process? • What substance is responsible fo reducing the iron oxide to iron? • What is the level of purity of the iron produced by this process?

31. https://www.youtube.com/watch?v=omGKUKwJPB8 Alloys Interstitial alloys, an atom fits in between the metal atoms in the crystal B, N, and C can often fit in the holes in a closest packed structure • usually a small nonmetal atom

32. STEEL MAKING Iron produced in the blast furnace is very brittle due to the high amount of carbon it contains. In the Basic Oxygen Process, high pressure O2 is blown over and through molten iron to burn off the excess carbon impurities. Ways of Removing of impurities SILICA add calcium oxide CaO + SiO2 ——> CaSiO3 CARBON add oxygen C + O2 ——> CO2 SULPHUR add magnesium Mg + S ——> MgS

33. TYPES OF STEEL LOW CARBON soft, easily shaped Contains 0.05% -0.32% carbon HIGH CARBON strong but brittle Contains 0.55%-1.5% carbon Makes chisels, razor blades, saws STAINLESS StEEL resistant to corrosion tools & cutlery (contains Cr and Ni)

34. EXTRACTION OF TITANIUM • titanium ores (titanium(IV) oxide - TiO2) are very common BUT • the oxide can be reduced by carbon but the titanium produced reacts with the carbon to give titanium carbide • So HALOGENS are used .The oxide is first converted to the chloride TiO2(s) + 2C(s) + 2Cl2(g) ——> TiCl4(l) + 2CO(g) •which is then reduced with sodium. TiCl4(l) + 4Na(s) ——> Ti(s) + 4NaCl(s) The reduction of TiCl4 is carried out in an atmosphere of argon because the titanium reacts with oxygen at high temperatures.

35. EXTRACTION OF TITANIUM • the oxide is first converted to the chloride TiO2(s) + 2C(s) + 2Cl2(g) ——> TiCl4(l) + 2CO(g) •which is then reduced with sodium. TiCl4(l) + 4Na(s) ——> Ti(s) + 4NaCl(s) The reduction of TiCl4 is carried out in an atmosphere of argon because the titanium reacts with oxygen at high temperatures.