Isolation of Metals - Methods of concentration of ore

  • Introduction to Isolation of Metals
  • Why do we need to concentrate ores?
  • Methods of concentration of ores:
    • Hydraulic Washing
    • Magnetic Separation
    • Froth Flotation
    • Leaching
    • Roasting and Calcination

Hydraulic Washing

  • Principle of Hydraulic Washing
  • Example: Concentration of Tin Ore
  • Process of Hydraulic Washing
    • Riffles
    • Slurry
    • Density Difference
    • Settling

Magnetic Separation

  • Principle of Magnetic Separation
  • Example: Concentration of Iron Ore
  • Process of Magnetic Separation
    • Magnet
    • Paramagnetic Materials
    • Ferromagnetic Materials
    • Non-magnetic Materials

Froth Flotation

  • Principle of Froth Flotation
  • Example: Concentration of Sulphide Ores
  • Process of Froth Flotation
    • Collectors
    • Frothers
    • Activators
    • Depressants

Leaching

  • Principle of Leaching
  • Example: Concentration of Gold Ore
  • Process of Leaching
    • Solvent
    • Leachate
    • Dilute Acid
    • Cyanide Solution

Roasting

  • Principle of Roasting
  • Example: Concentration of Zinc Ore
  • Process of Roasting
    • Heating
    • Volatile Impurities
    • Oxidation
    • Formation of Metal Oxides

Calcination

  • Principle of Calcination
  • Example: Concentration of Aluminium Ore
  • Process of Calcination
    • Heating
    • Decomposition
    • Loss of Volatile Impurities
    • Formation of Metal Oxide
    • Calcined Ore

Comparison of Methods

  • Comparison of Hydraulic Washing, Magnetic Separation, and Froth Flotation
  • Efficiency of each method
  • Applicability to different ores
  • Factors influencing the choice of method

Summary

  • Recap of the Methods of Concentration of Ores
  • Importance of Concentration of Ores in Isolation of Metals
  • Brief overview of Hydraulic Washing, Magnetic Separation, Froth Flotation, Leaching, Roasting, and Calcination
  • Key points to remember for the 12th Boards exam

Questions

  • Interactive session for students to ask questions
  • Clarify doubts related to the topic
  • Discuss related examples and equations
  • Encourage active participation and engagement
  1. Hydraulic Washing
  • Principle: It is based on the difference in the densities of the ore and the gangue particles.
  • Example: Concentration of Tin Ore using Hydraulic Washing:
    • Tin ore is heavy and associated with lighter gangue particles.
    • The crushed ore is fed into a tank with water and a current of water is passed through it.
    • The lighter gangue particles are washed away, while the heavier tin ore is settled at the bottom.
  • Riffles: Used to trap the heavy ore particles.
  • Slurry: Mixture of ore particles and water.
  • Density Difference: The difference in densities is utilized to separate the ore from the gangue.
  1. Magnetic Separation
  • Principle: This method is used when either the ore or the impurities are magnetic in nature
  • Example: Concentration of Iron Ore using Magnetic Separation:
    • Iron ore is magnetic, while the gangue particles are non-magnetic.
    • A magnet is used to separate the magnetic particles from the non-magnetic ones.
  • Magnet: Used to attract the magnetic particles.
  • Paramagnetic Materials: Materials weakly attracted by the magnet.
  • Ferromagnetic Materials: Materials strongly attracted by the magnet.
  • Non-magnetic Materials: Materials not attracted by the magnet.
  1. Froth Flotation
  • Principle: This method is based on the difference in the wetting properties of the ore and the gangue particles.
  • Example: Concentration of Sulphide Ores using Froth Flotation:
    • Sulphide ores are hydrophobic, while the gangue particles are hydrophilic.
    • Collectors and frothers are added to the ore-water mixture.
    • Air bubbles are introduced, which carry the sulphide ore particles to the surface to form froth, while the gangue particles sink.
  • Collectors: Substances that enhance the affinity of ore particles to air bubbles.
  • Frothers: Substances that stabilize the froth formed.
  • Activators: Substances that activate the collector.
  • Depressants: Substances that depress the gangue particles.
  1. Leaching
  • Principle: This method is used when the ore is soluble in a suitable solvent.
  • Example: Concentration of Gold Ore using Leaching:
    • Gold ore is treated with a dilute solution of cyanide or dilute sulphuric acid to dissolve the gold.
    • The gold is then recovered from the leachate by various methods.
  • Solvent: The liquid used to dissolve the desired metal from the ore.
  • Leachate: The solution containing the dissolved metal.
  • Dilute Acid: Used in the leaching process to dissolve the metal.
  • Cyanide Solution: Used specifically for the leaching of gold ore.
  1. Roasting
  • Principle: This method is used when the ore is a sulphide or a carbonate.
  • Example: Concentration of Zinc Ore using Roasting:
    • Zinc ore is heated in the presence of excess oxygen.
    • The sulphide ore is converted to oxide, and volatile impurities are expelled.
  • Heating: The ore is subjected to high temperatures in the presence of air.
  • Volatile Impurities: Impurities that can be expelled as gases during the roasting process.
  • Oxidation: The conversion of the sulphide ore to an oxide.
  1. Calcination
  • Principle: This method is used when the ore is a carbonate or a hydrated oxide.
  • Example: Concentration of Aluminium Ore using Calcination:
    • Aluminium ore is heated to a high temperature in the absence of air.
    • The carbonate or hydrated oxide is converted to an oxide, releasing volatile impurities.
  • Heating: The ore is subjected to high temperatures in a controlled environment.
  • Decomposition: The breaking down of compounds into simpler substances.
  • Loss of Volatile Impurities: Volatile impurities are expelled during calcination.
  • Formation of Metal Oxide: The desired metal oxide is obtained upon calcination.
  1. Comparison of Methods
  • Hydraulic Washing vs. Magnetic Separation vs. Froth Flotation
  • Efficiency: Evaluate the effectiveness of each method in concentrating the desired ore.
  • Applicability: Discuss which method is suitable for different types of ores.
  • Factors: Consider factors such as cost, environmental impact, and availability of resources.
  • Choice of Method: Explore the factors that influence the selection of an appropriate concentration method.
  1. Summary
  • Recap: Review the methods of concentration of ores.
  • Importance: Emphasize the significance of ore concentration in extracting metals.
  • Overview: Provide a brief summary of Hydraulic Washing, Magnetic Separation, Froth Flotation, Leaching, Roasting, and Calcination.
  • Key Points: Highlight the main concepts and processes related to isolation of metals from ores.
  • Preparation: Encourage students to consolidate their understanding of the topic for the Boards exam.
  1. Questions
  • Interactive Session: Engage students in a discussion.
  • Clarify Doubts: Address any concerns and queries related to the topic.
  • Examples and Equations: Present relevant examples and equations to solidify understanding.
  • Participation: Encourage active participation from students.
  • Review: Reinforce key concepts and provide additional explanations as needed.
  1. Thank You!
  • Acknowledge the participation and effort of the students.
  • Provide any additional information or resources for further study.
  • End the lecture on a positive note, encouraging students to continue their learning journey in chemistry. Here are slides 21 to 30 for teaching the topic “Isolation of Metals - Methods of Concentration of Ore” in markdown format:
  1. Hydraulic Washing:
  • Principle: Difference in densities of ore and gangue particles.
  • Example: Concentration of Tin Ore using Hydraulic Washing.
  • Process:
    • Crushed ore + water in a tank.
    • Water current separates lighter gangue particles.
    • Settling of heavier tin ore at the bottom.
  • Riffles used to trap heavy ore particles.
  • Slurry: Mixture of ore particles and water.
  1. Magnetic Separation:
  • Principle: Difference in magnetic properties of ore and gangue.
  • Example: Concentration of Iron Ore using Magnetic Separation.
  • Process:
    • Use of a magnet to separate magnetic particles.
    • Paramagnetic materials weakly attracted to the magnet.
    • Ferromagnetic materials strongly attracted to the magnet.
    • Non-magnetic materials not attracted to the magnet.
  1. Froth Flotation:
  • Principle: Difference in wetting properties of ore and gangue.
  • Example: Concentration of Sulphide Ores using Froth Flotation.
  • Process:
    • Addition of collectors and frothers to ore-water mixture.
    • Introduction of air bubbles to form froth.
    • Sulphide ore particles float on the froth.
    • Gangue particles sink to the bottom.
    • Collectors enhance ore affinity to air bubbles.
    • Frothers stabilize the froth formed.
  1. Leaching:
  • Principle: Ore dissolution in a suitable solvent.
  • Example: Concentration of Gold Ore using Leaching.
  • Process:
    • Treatment of ore with a dilute solution of cyanide or sulphuric acid.
    • Dissolving the gold into a leachate.
    • Recovery of gold from the leachate by various methods.
  • Solvent: Liquid used to dissolve the desired metal.
  • Leachate: Solution containing the dissolved metal.
  1. Roasting:
  • Principle: Conversion of sulphide or carbonate ore to an oxide.
  • Example: Concentration of Zinc Ore using Roasting.
  • Process:
    • Heating of ore in the presence of excess oxygen.
    • Sulphide ore converted to an oxide.
    • Volatile impurities expelled.
  • Heating: Subjecting ore to high temperatures.
  • Volatile Impurities: Gases expelled during roasting.
  1. Calcination:
  • Principle: Conversion of carbonate or hydrated oxide ore to an oxide.
  • Example: Concentration of Aluminium Ore using Calcination.
  • Process:
    • Heating the ore to high temperatures in the absence of air.
    • Decomposing the carbonate or hydrated oxide.
    • Volatile impurities expelled.
  • Decomposition: Breaking compounds into simpler substances.
  • Loss of Volatile Impurities: Expulsion of volatile impurities.
  1. Comparison of Methods:
  • Hydraulic Washing, Magnetic Separation, Froth Flotation.
  • Evaluate efficiency of each method.
  • Consider applicability to different types of ores.
  • Factors influencing choice of method:
    • Cost, environmental impact, resource availability.
  1. Summary:
  • Recap of concentration methods used in isolation of metals.
  • Importance of ore concentration in metal extraction.
  • Overview of Hydraulic Washing, Magnetic Separation, Froth Flotation, Leaching, Roasting, and Calcination.
  • Key Points to remember for the Boards exam.
  • Consolidate understanding for better preparation.
  1. Questions:
  • Interactive session for student engagement.
  • Address doubts and queries related to the topic.
  • Present relevant examples and equations for better comprehension.
  • Encourage active participation from students.
  • Review and reinforce key concepts.
  1. Thank You!
  • Appreciate students’ participation and effort.
  • Provide additional resources for further study.
  • End the lecture on a positive note, encouraging continued learning in chemistry.