Metallurgy Notes: Extraction of Metals and Alloys | PDF

Okay, here is the conversion of the document/images into a structured markdown format. I have done my best to transcribe the text, format it, include LaTeX math formulas and describe any diagrams in detail. ### 2-10-2024 Date: 22 Mineral, ores, flux, branque (Constantin), metallurgy. "Education p...

Okay, here is the conversion of the document/images into a structured markdown format. I have done my best to transcribe the text, format it, include LaTeX math formulas and describe any diagrams in detail. ### 2-10-2024 Date: 22 Mineral, ores, flux, branque (Constantin), metallurgy. "Education prevents rust" Ch-, Metallurgy Define 1) Minerals - The compounds of various metals found in nature associated with their earthly impurities are called mineral. 2) Ores- The naturally occurring mineral from which metals can be extracted profitably and conventionally are called ore. 3) Flux - The substance added to the ore to get rid of matrix resulting to formation of fusible compound slag. 4) Gangue [Matrix]- The rocky impurities including silica mud etc associated with ore is called matrix or gangue 5) Metallurgy - The large scale process involved in extraction of pure metal from their respective ore is called metallurgy. ### Steps involved in Metallurgy I Concentration of Ore /Ore enrichment / Ore dressing IⅡ Conversion of Ore into Oxide III Extraction of Metal from Oxide IV Refining of Metal I Concentration of Ore Ore enrichment / Ore dressing We remove the earthly Impurities from Ore a) Magnetic Separation Method: This process is used to remove non-magnetic impurities from a magnetic or vice-versa. This method is used to concentrate for iron ore. b) Froth Floatation Method. This method is used for the enrichment of Sulphide ores. The principle of this method is based one of it with oil. Observation When hot air is blown then ore with oil comes in the form of foam or froth comes on the surface & water 6) Gravity Seperation Method (Hydrolytic Method) This method of concentrating the ore is based on the density of the particles. The ore is poured over vibrating slope table. When a jet of water is flown over it, the denser ore particles settle down in the ore, and the lighter impurities will flow away with the running water. Chemical Method- A chemical substance is used to conc. the ore. Ex-use of $\text{NaOH}$ in balycon to conc. After conc. the ore is concentrated (free from earthly impurity. **II Conversion of Concentrated ore into oxide-** After the conc. of ore, the ore is converted into its oxide because oxides can easily be reduced to metal a) Roasting- Process of heating of conc. ore in the presence of excess of air. at high temperature before it is converted to metal. $2 \text{ZnS} +3\text{O}_2 \longrightarrow 2\text{ZnO} + 2SO_2$ $4 \text{FeS}_2 + 11\text{O}_2 \longrightarrow 2\text{Fe}_2\text{O}_3 + 8SO_2$ Note- Roasting is generally used for sulphite ores b) Calcination - Process of heating of conc ore in the absence of air or in the limited supply of air at a temperature below its melting point. Calcination is usually carried for carbonate ores $\text{ZnCO}_3 \longrightarrow \text{ZnO} + \text{CO}_2$ $\text{Fe CO}_3 \longrightarrow \text{Fe O} +\text{CO}_2$ ### III Extraction of Metal from its Oxides OR Reduction of Mettalic Oxide to metal a) $\text{K}$ $\text{Na}$ $\text{Ca}$ $\text{Mg}$ These elements are extracted from its oxide by electrolytic reduction of electrolysis Reason- These elements are highly reaction and electropositive, they have strong affinity for oxygen. Their oxides are highly stable Ex- molten $\text{NaCl} \leftrightharpoons \text{Na}^+ + \text{Cl}^-$ reaction at cathode - $\text{Na}^+ + 1e \longrightarrow \text{Na}$ b) $\text{Zn}$ $\text{Fe}$ $\text{Pb}$ $\text{Cu}$ These metals are extracted from its oxide by the use of Reducing agent. Reason - These metals are less reactive having less affinity for oxygen. Their oxide is less stable. $\text{Ex-} \text{ZnO} + \text{C} \longrightarrow \text{Zn} + \text{Co}$ $\text{PbO} + \text{C} \longrightarrow \text{Pb} + \text{Co}$ $\text{CuO} + \text{H}_2 \longrightarrow \text{Cu} + \text{H}_2\text{O}$ $\text{Fe}_2\text{O}_3+ 3\text{CO} \longrightarrow 2 \text{Fe} +3\text{CO}$ c) $\text{Hg}$ $\text{Ağ}$ These metals are very less reactive. They have very less affinity for oxygen, their oxides are very less stable. Hence Thermal Decomposition can be used to extract metal from its oxides. $\text{Ex-} 2\text{HgO} \longrightarrow 2\text{Hg} + \text{O}_2$ (Mercury (II) oxide) $2 \text{Ag}_2\text{O} \longrightarrow 4\text{Ag} + \text{O}_2$ (Silver (II) oxide) Extraction of Alluminium from Bauxite ore. Ore - Bauxite ore Formula-$\text{Al}_2\text{O}_3 \cdot 2\text{H}_2\text{O}$ Concentration of Bauxite Ore Method - Chemical method Process - Baeyer's process Chemical used-conc. $\text{NaOH}$ soln [Conc. Alkali Soln]. Concentrated $\text{NaOH}$ is used to concentrate Bauxite Ore because oxide bauxite being amphoteric reacts with $\text{NaOH}$ solution while impurities like $\text{Fe}_2\text{O}_3$ and $\text{SiO}_2$ will not react. $\text{Al}_2\text{O}_3\cdot 2\text{H}_2\text{O} + 2\text{NaOH} \longrightarrow \text{NaAlO}_2 + 3\text{H}_2\text{O}$ $\text{NaAlO}_2 + 2\text{H}_2\text{O} \longrightarrow \text{NaOH} + \text{Al(OH)}_3$ $2\text{Al(OH)}_2 \longrightarrow \text{Al}_2\text{O}_3 + 3 \text{H}_2\text{0}$ Allemina (conc) II Conversion of concentrated ore to oxide This step is not required as conc. ore is already in the form of oxide III Extraction of Al from $\text{Al}_2\text{O}_3$ Process - Hall - Heroult Process Method - Electrolytic reduction / Electrolysis Difficulties faced in the extraction of extraction of Al from $\text{Al}_2\text{O}_3$ $\text{Al}_2\text{O}_3$ has a melting point of $2050^\circ\text{C}$ and is almost non-conductor of electricity at such high temperature, huge amount of electrical energy is required moreover Aluminium may itself volatise at such high temperature. In order to oversome such difficulties, molten alla alumina $[\text{Al}_2\text{O}_3]$ is mixed with cryolite and Flourpar $[\text{Caf}_2]$ in the ratio of $1:3:1$ Advantage of Cryolite and Flourspar Gryolite and flourspar lowers the melting point of $\text{Al}_2\text{O}_3$ from $2050^\circ\text{C}$ to $950^\circ\text{C}$ They increases the mobility of the morture. Advantage of Gyolite Gyolite increases the conductivity of mixture It lowers the melting point of molten $\text{Al}_2\text{O}_3$ from $2050^\circ\text{C}$ to $950^\circ\text{C}$. Note:- Cryolite dissolves $\text{Al}_2\text{O}_3$ in the molten state of subdivision. NTF: Solvent for molten $\text{Al}_2\text{O}_3$ - Gyolite Electrolytic reactions $\text{Al}_2\text{O}_3 \longrightarrow 2 \text{Al}^{3+} + 3\text{O}^{2-}$ $\text{Na}_3 \text{AlF}_6 \longrightarrow 3 \text{Na}^+ \text{Al}^{3+} + 6\text{F}^-$ $\text{Caf}_2 \longrightarrow \text{Ca}^{2+} + 2\text{F}^-$ reaction at cathode - $\text{Al}^{3+} + 3e^- \longrightarrow \text{Al}$ reaction at anode $\text{O}^{2-}-2e^- \longrightarrow \text{O}$ $\text{O} + \text{O} \longrightarrow \text{O}_2$ Give Reason Number of graphite rods are used as anode in the Hall - Heroult process/Graphite rods are periodically may in the Hall - Heroult process because Oxygen gas evolved at anode oxidises graphite anode into Carbon monoxide and carbon dioxide. Coke powder is sprinkled over electrolytic misture in the hall - Heroult process because its prevents heat loss radiation. by ii) reduces the burning of graphite anode at the point where oxygen emerge from the bath 9 Hall-Heralt process is a continuous process Refining of Aluminium (Hoope's Process) Electrolytes - $\text{Caf}_2$ $\text{Ba F}_2$ $\text{Al F}_2$ $\text{Na}_3 \text{AlF}_6$ Reaction at Cathode $-\text{Al}^{3+} + 3e^- \longrightarrow \text{Al}$ Reaction at anode $-\text{Al} -3e \longrightarrow \text{Al}^{3+}$ Alloys:- It is a substance prepared by adding other metals or mon-metal to a base metal in appropriate proportion to obtain urbain desirable properties. It is usually made by melting the components together and then solidifying the mixture its components must be mixable in liquid state and do not separate on solidification. Its properties are intermediate between those of the metals composing them. | Alloy | Composition | User | | ----------- | ----------- | ----------- | | 1) Brass | (Cu) + Zn |Electrical fitting, Decorative article | | 2) Bronze |Cut Zn + Sn |Statues, medal & coins| | 3) Durabemin | $\text{Al} + \text{Mg} + \text{Mn+Cu}$ | Aircraft, light tools, cookers | | 4) Magnalium | $\text{Al} + mg$ | Aircraft & scientific tool | | 5) Solder | $\text{Pb} + \text{Sn}$ | electrical fuse, soldering purpo | | 6) Stainless steel | $\text{Fe} + \text{Ni} + \text{Gr} + \text{C}$ | Utensils, cutlery, Autor, Surgical instruments | Give Reason In the alloy solder tin is used because it lowers the melting point of of the alloy 2 The role of zinc in brass is that it import copper. 3 In the alloy stainless steel nickle and chronium imparts luster to the alloy and carbon imparts hardness 4 In the alloy duralumin or magnelium, alluminium imper lightness to the allow and magnesium imparts strength to the alloy. and magnesiam impart streve PYQS Name the following :- 1) Important ore of alluvinium - boxite $[\text{Al}_2 \text{O}_3\cdot 2\text{H}_2\text{O}]$ Groyolite $[\text{Na}_3 \text{AlF}_6]$ 2) Important ore of zinc - Zine blend - $[\text{2m5}]$ Calamine - $[\text{Zn Co}_3]$ 3) Important Sulphide of iron - $\text{Fe}_2\text{O}_3$ - Haematide $\text{Fe}_3 \text{O}_4$ - Magnetide 4) A monovalent and a trivalent metal present in Cryolite Monovalent - Na Trivalent - Al 5 A divalent metal present in florosport- Calcium 6) A chemical used to conc. bavaite - $\text{NaOH}$ soln [Conc.] 7) Main impurities present in Lovute ore-$\text{Fe}_2\text{O}_3$,$\text{Sil}_2$ 8 A soluble salt formed when bonite reacts with Coric. $\text{NaOH}$ solution-$\text{NaAlO}_2$ 9) Process used for the enrichprent of Sulphide ores Froth floatation method 10) Temperature required to convert aluminium hydroxide to akeminin onide- $1100^\circ\text{c}$ 11) Process used to extract aluminium from aluminium oxide Hall-Heroult process 12) Process used to concentrate boxite ore - Bayer's Process 13) Role of conc. $\text{NaOH}$ by virtue of which it is used to conc. Boxite ore - Amphoteric Nature of Boxite Ore 14)State the base metal and the composition of the follows. olloys Brass - → Imports hardness to copper Cu + Zn Sur Tin Bronze - Cu + Zn + Sn-lowrs alloy 30 Solder - Pb + Sn imps lightnes Al+ Mg + Mn + Cu Stainless steel-+ Nita+C An alloy in which one of the metal component is mercury - Amalgam Northg ← Sodium Amalgom Zn-Hg → Zinc Amalgom 5 Roasting is carried for sulphide ores and calcination s carried out of for carbonate ores 16 A method of ore, is concentrating the ore, an taken in full pulverised form magnetic seperation 17-S 5 7 method used to conc. the ore based on the diff in the density of ore particles and impurities hydrolytic method os gravity seperation method 18 An observation noticed during the enrichment of sulphide - sulphide ores ore comes in the form of foam or froth tin in + 2 81 Role of tin in the alloy solder hin lowers the melting point of the alley 91 Role of zinc in the alloy, copper. zinc mparts hardness to aluminun an Aluminum mparts lightness whit strength. m 3-301 Role of alluminiom in the alloy inparts magnetism -8 A Reaction at process 20 -Reaction at cathode - Al *3 + 3e - Reaction at -