What defines a mineral in the context of metallurgy?

A mineral is a naturally occurring chemical substance in which metal exists either in its free state or in a combined state.

What is the gangue in relation to ores?

Gangue refers to the impurities associated with the ore that are not economically extracted.

Differentiate between carbonate ores and nitrate ores with examples.

Carbonate vs Nitrate Ores Explained

• Carbonate ores like siderite.

• Nitrate ores include Chile saltpeter.

• Different chemical compositions matter.

What are native ores and provide examples?

Native ores are unreactive metals.

• Found in the earth's crust.

• Examples include gold and silver.

• Used in various industrial applications.

What is the first step in the extraction of metal from ore?

The first step is pulverization, which involves crushing the ore to a powdered state.

Explain the process of concentration or dressing of ore.

Concentration removes gangue from ore.

• Gravity separation uses density differences.

• Magnetic separation targets magnetic minerals.

• Froth flotation separates based on hydrophobicity.

Fill in the blank: Froth flotation process is primarily used for the concentration of ___ ores.

Sulphide

What role do frothers play in the froth flotation process?

Frothers stabilize froth in flotation.

• Reduce water surface tension.

• Enhance separation efficiency.

• Aid in ore recovery process.

True or False: In the leaching process, the metallic ore is dissolved in a solvent while impurities remain insoluble.

True

What is calcination and when is it carried out?

Calcination is a heating process.

• Removes volatile impurities.

• Used for metal ores.

• Conducted in absence of air.

Describe the reduction of metal oxides and list methods used.

Reduction of metal oxides is key.

• Chemical reduction removes oxygen.

• Self-reduction occurs naturally.

• Electrolytic reduction uses electricity.

In the context of metallurgy, what is the significance of the Ellingham diagram?

Ellingham diagram predicts metal oxide feasibility.

• Shows Gibbs free energy changes.

• Indicates temperature effects on reduction.

• Guides metallurgical processing decisions.

Fill in the blank: The process of combining flux with impurities during metal extraction is called ___.

Smelting

What types of flux are used in metallurgy and their purposes?

Basic fluxes, like CaO or MgO, are used to remove acidic impurities, while acidic fluxes, like SiO₂ or B₂O₃, are used to remove basic impurities.

Explain how hydrogen can be used as a reducing agent in metallurgy.

Hydrogen can reduce metal oxides to metals by reacting with them at high temperatures, though its use is limited due to its flammability.

What is the Kroll process and for which metals is it used?

The Kroll process is used for extracting titanium and zirconium from their chlorides using magnesium as a reducing agent.

Fill in the blank: During electrolysis, the metal is deposited at the ___ electrode.

Cathode

Explain the importance of using a flux during the smelting process.

Flux lowers the melting point of impurities, allows for easier separation from molten metal, and prevents oxidation by covering the molten metal.

True or False: The reduction of sulphide ores directly to metals is thermodynamically feasible.

False: Sulphide ores are first roasted to metal oxides before reduction.

What is a metal displacement method in the context of metallurgy?

Metal displacement method involves treating concentrated ore with a more electropositive metal to displace and extract the less electropositive metal.

Describe the role of activators and depressants in the froth flotation process.

Activators and depressants aid flotation.

• Activators increase mineral wettability.

• Depressants reduce specific mineral float.

• Selective separation enhances efficiency.

What is the final step in the extraction of metals from ores?

The final step is the purification or refining of the crude metal to achieve the desired purity level.

Riddle: I separate metals from their ores through chemical reactions, but without me, extraction may fail. What am I?

A reducing agent