Metallurgy

Step 1: Definition.
Slag is the fusible (molten) waste material or by-product formed during the extraction of metals from their ores in a furnace. It mainly consists of impurities combined with flux.
Step 2: Formation.
In metallurgical processes, flux is added to combine with the gangue (earthy impurities like SiO , Al O ) to form slag. This slag is lighter and floats on the molten metal surface, protecting it from oxidation.
Step 3: Function of slag.
- Removes impurities.
- Acts as a protective layer for the molten metal.
- Prevents oxidation.
Step 4: Example.
In the extraction of iron from hematite in a blast furnace, limestone (CaCO ) acts as flux and reacts with silica impurities to form calcium silicate (slag).

Step 1: Nature of noble gases.
Noble gases (He, Ne, Ar, Kr, Xe, Rn) are monoatomic and chemically inert elements. They exist as isolated atoms rather than molecules.
Step 2: Mode of atomic radius measurement.
For noble gases, the atomic radius is determined as van der Waals radius, while for other elements, it is usually the covalent radius.
Step 3: Explanation.
The van der Waals radius is the distance between the nuclei of two non-bonded atoms in adjacent molecules. This distance is always larger than the covalent radius because the atoms are not bound tightly.
Step 4: Conclusion.
Hence, noble gases have comparatively large atomic radii because their atomic radius is measured as the van der Waals radius, not the covalent radius.

Step 1: Recall metallurgical process.
Smelting is the process in which a metal oxide is reduced to the free metal using carbon (coke) or carbon monoxide in a furnace.
Step 2: Analyze options.
- Roasting: heating sulfide ores in presence of oxygen, not reduction.
- Calcination: heating ores in absence of air, used to remove volatile impurities.
- Leaching: extraction using chemical solvents.
- Smelting: correct, involves reduction with carbon/CO.
Step 3: Conclusion.
Hence, the process is called Smelting.

Step 1: Recall cyanide process.
Cyanide process (MacArthur-Forrest process) is used for the extraction of gold (Au) and silver (Ag) from their low-grade ores.
Step 2: Check given options.
- Cr: not extracted by cyanide method.
- Ag: correct, silver is extracted by leaching with NaCN or KCN solution.
- Cu: not by cyanide process, usually by hydrometallurgy or smelting.
- Zn: extracted mainly by roasting and reduction.
Step 3: Conclusion.
Therefore, cyanide process is used for the extraction of Silver (Ag).

Step 1: Identify iron ores.
Major iron ores: Haematite (Fe O ), Magnetite (Fe O ), Limonite, Siderite (FeCO ).
Step 2: Choose oxide ore.
Among the options, Haematite is the oxide (Fe O ) and a principal commercial ore of iron.
Step 3: Eliminate others.
Siderite is a carbonate; Pyrite is sulphide (FeS ); Bauxite is an aluminium ore.
Step 4: Conclusion.
Hence, the correct answer is (B) Haematite.

Step 1: Definition.
Bessemerisation is a metallurgical process used for the purification of metals, particularly for converting impure molten pig iron into steel or copper matte into pure metal.
Step 2: Principle.
In this process, air or oxygen is blown through molten metal, which oxidizes impurities such as carbon, silicon, sulfur, and iron into gaseous oxides or slag that can be removed.
Step 3: Reactions involved.
FeO then combines with silica to form slag (FeSiO ), which floats and is removed.
Step 4: Application.
Used in the refining of copper and steel.
Step 5: Example.
In the Bessemer converter, impure blister copper is oxidized and converted into pure copper metal.

Step 1: Common Ores of Iron.
Iron is extracted from various ores, the two most common being hematite and magnetite.
Step 2: Names and Formulae.
- Hematite:
- Magnetite:
Step 3: Explanation.
- Hematite is the most widely used ore of iron, and it contains iron in the +3 oxidation state.
- Magnetite is another important ore that contains iron in both +2 and +3 oxidation states.

Step 1: Purpose of Cryolite.
Cryolite (Na₃AlF₆) is used in the extraction of aluminum through the Hall-Héroult process. Its main function is to lower the melting point of aluminum oxide (Al₂O₃) and increase its conductivity during electrolysis.
Step 2: Advantages. - Cryolite helps in dissolving Al₂O₃ at a lower temperature, reducing the energy consumption of the process.
- It also allows for the extraction of aluminum metal at a much lower temperature (around 950°C) than pure Al₂O₃ would require (around 2000°C).

Step 1: Define flux, gangue, alloy, and slag.
- Flux is a substance used to help in the extraction of metals, like in smelting. - Gangue refers to the unwanted minerals or impurities that are found in ore. - Alloy is a mixture of two or more metals. - Slag is the byproduct formed when impurities are separated from ore.
Step 2: Identify the correct term for ore impurities.
The impurities in ores are typically known as gangue.
Final Answer:

Step 1: Understand the process of smelting.
Smelting is a metallurgical process where metal oxides are reduced to pure metal. It generally requires a reducing agent, which removes oxygen from the metal oxide.
Step 2: Identify the correct reducing agent.
- Aluminum (Al) and magnesium (Mg) can be used in certain reactions, but carbon (C) is the most common reducing agent for smelting. - Carbon reacts with oxygen in metal oxides to produce carbon dioxide and pure metal.
Step 3: Apply to the options.
Carbon (C) is widely used in smelting processes, making it the correct choice.
Final Answer:

Step 1: Understand the concept of ore concentration.
Concentration of an ore refers to the process of removing impurities (gangue) from the ore, so that the metal content becomes more concentrated. This is an essential step in metallurgy, as it increases the efficiency of the extraction process.
Step 2: Methods of Concentration of Ores.
There are several methods used to concentrate ores, depending on the nature of the ore and the gangue. These methods include: 1. Hydraulic Washing (Gravity Separation): This method is used when the ore and gangue have different densities. The ore is washed with water, and the denser ore particles settle at the bottom, while the lighter gangue particles are washed away. 2. Froth Flotation: This method is used for ores that are sulfide ores, such as copper and lead ores. The ore is mixed with water and a frothing agent to form a froth. The ore particles attach to the bubbles and rise to the surface, where they can be separated from the gangue. 3. Magnetic Separation: This method is used for ores containing magnetic minerals. A magnetic field is applied to attract the magnetic ore particles, which are then separated from the non-magnetic gangue. 4. Leaching: Leaching involves using a solvent to dissolve the metal from the ore. This method is often used for ores of aluminum (bauxite) and gold. The ore is treated with a chemical solvent (e.g., cyanide for gold), and the metal is then recovered from the solution. 5. Electrostatic Separation: In this method, the ore is subjected to an electrostatic field, and the charged particles are separated. This method is used for separating ores of non-metallic minerals.
Step 3: Conclusion.
The concentration of ores is an essential part of the extraction process. The method used depends on the physical and chemical properties of the ore and the gangue.
Final Answer: Concentration of an ore is the process of separating the useful metal from the gangue, and various methods like hydraulic washing, froth flotation, magnetic separation, leaching, and electrostatic separation are used depending on the nature of the ore.
Final Answer:

Step 1: Definition of Slag.
Slag is a by-product of metal smelting, formed when impurities in the metal ore combine with flux (a substance used to remove impurities during smelting). Slag consists of metal oxides and other compounds and floats on top of the molten metal due to its lower density.
Step 2: Formation of Slag.
During the smelting of metals like iron or copper, the flux combines with the gangue (impurities) to form slag. The slag is then removed from the top of the molten metal.
Step 3: Uses of Slag.
- Slag is used in the production of cement and as a building material. - It can also be used as a fertilizer due to its mineral content.
Final Answer: Slag is the by-product of metal smelting, consisting of metal oxides and other compounds, and is used in various industrial applications.
Final Answer:

Step 1: Understand the given process.
The given equation shows the process where Titanium (Ti) reacts with chlorine to form Titanium tetrachloride (TiCl4) and then undergoes a further reaction at a higher temperature, resulting in the formation of Titanium metal. This process is used for the purification of metals.
Step 2: Identify the purification process.
- Cupellation is a process used to separate noble metals from base metals by heating them in a special furnace. - Poling is a method used for removing dissolved gases from molten metals. - Van Arkel method is used for the purification of certain metals, especially titanium, by converting them into a volatile compound, which is then decomposed. - Zone refining is a process used to purify metals by melting a small region of the metal and then moving it along the metal rod, gradually purifying the material as impurities concentrate in the molten region.
Step 3: Apply to the options.
The process shown in the equation is similar to the Zone refining process, used extensively for purifying metals like titanium.
Final Answer:

Step 1: Understand the electrolysis process.
Electrolysis is the process of using electricity to break down compounds into their components. It is commonly used for extracting metals from their ores.
Step 2: Analyze each option.
- Sodium (Na) and Magnesium (Mg) are both extracted using electrolysis. - Aluminum (Al) is also extracted by electrolysis in the Bayer process. - Iron (Fe) is typically extracted by reduction using carbon, not by electrolysis.
Step 3: Apply to the options.
Iron (Fe) is the metal that is not obtained by electrolysis, making option (D) correct.
Final Answer: