Refining of ores Metallurgy

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 Refining of ores Metallurgy

Metallurgy

Metallurgy is the process of obtaining metals from ores. It may be defined as the processes which are involved in the extraction of metals from their ores and then refining them for use are known as metallurgy.

Steps of Metallurgy:
Metals can be extracted from their ores by following processes:

Enrichment of Ore or Concentration of Ore

Conversion of concentrated ore into Metal oxide

Reduction of metal Oxide to metal

Purification or Refining of Impure metal

 

ENRICHMENT OF ORE OR CONCENTRATION OF ORE

 

Before extracting the metal from an ore, it is necessary to remove the impurities present in it. By removing these impurities we get a concentrated ore which contains a high Percentage of metal in it. The process of removal of gangue particles from an ore to increase the percentage of metal in ore is called enrichment of ore. The processes used for removing the impurities from ores depend on the difference between physical or chemical properties of the ore and of the impurities.

Methods of enrichment of ore: 

Now, we shall discuss the different processes which are used for enrichment of different types of ores.

1. Hydraulic Washing

This method is used for the enrichment of those ores which are heavier than gangue particles present in them. In this method, a stream of water is passed through crushed and finely powered ore. The Lighter gangue particles are washed away with water while the heavier ore particles are left behind. Oxide ores of tin and lead are concentrated by this method.

2. Froth Floatation Process

This method is used for concentration of sulphide ores of copper, lead and zinc. In this method, powdered ore is put in a tank full of water. And then, some Pine oil is added to it. In the tank the particles of sulphide ore are wetted by pine oil whereas the gangue particles are wetted by water. Then air is passed through this mixture. This results in the agitation of water in tank, which cause the sulphide ore particles to stick with the oil and rise to the surface in the form of froth. The gangue particles being heavier remain behind at the bottom of water tank. The froth is separated and concentrated sulphide ore is obtained from it.

 

  1. Magnetic Separation

    This method is used for concentration of magnetic ores of iron (magnetite and chromite) and manganese (pyrolusite) by removing non-magnetic impurities present in them. This process involves the use of a magnetic separator.
    A magnetic separator consists of a leather belt which moves over two rollers. Out of two rollers one roller has a magnet in it. In this method, the finely powdered magnetic ore is dropped over the moving belt at one end. When the powdered ore falls down from the moving belt at the other end having a magnetic roller, the particles of ore are attracted by the magnet and form a separate heap from the non- magnetic impurities.

 

  1. Chemical Separation

    This method is based on the differences in some chemical properties of the gangue and the ore. For example, the impure ore of metal aluminium (bauxite or aluminium oxide) is concentrated by Baeyer’s process.

    Baeyer’s Process

    In Baeyer’s process, the finely powdered bauxite ore is treated with hot sodium hydroxide solution to form a water soluble compound called sodium aluminate.

    Al2O3 +      2NaOH            2NaAlO2      +      H2O
    Bauxite      Sodium hydroxide                    Sodium aluminate        Water

    The gangue present in bauxite does not react in sodium hydroxide sol, so the gangue can be separated by the process of filtration. After filtration, the filtrate containing solution of sodium aluminate is acidified with HCl to form precipitates of aluminium hydroxide.

    NaAlO2      +      HCl    +    H2O       Al(OH)3    +    NaCl

Sodium aluminate   Hydrochloric acid                           Aluminium hydroxide      Salt

 

The precipitates of aluminium hydroxide are then filtered, washed, dried and heated to get pure aluminium oxide.

2Al(OH)3            Al2O3      +      3H2O
Aluminium Hydroxide                    Aluminium Oxide

It should be noted that pure aluminium oxide is also known as alumina.

 

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Pyrometallurgy is a process that uses heat to extract metals from ores. The ore is heated to a high temperature, which causes the metal to melt and separate from the other Minerals in the ore. The molten metal is then poured into molds to create ingots or other shapes.

Hydrometallurgy is a process that uses water to extract metals from ores. The ore is crushed and then mixed with a solution of acids or bases. The metal dissolves in the solution, and then it is separated from the other minerals in the ore using a process called electrolysis.

Electrometallurgy is a process that uses electricity to extract metals from ores. The ore is crushed and then mixed with a solution of salts. The metal is dissolved in the solution, and then it is separated from the other minerals in the ore using a process called electrolysis.

Biometallurgy is a process that uses bacteria to extract metals from ores. The ore is crushed and then mixed with a solution of nutrients. The bacteria then convert the metal in the ore into a form that can be easily extracted.

Direct recycling is a process that uses recycled materials to create new products. The recycled materials are melted and then poured into molds to create ingots or other shapes.

Indirect recycling is a process that uses recycled materials to create new products, but the recycled materials are not melted. The recycled materials are instead used to create new products, such as batteries or electronics.

Beneficiation is a process that removes impurities from ores. The ore is crushed and then mixed with a solution of acids or bases. The impurities dissolve in the solution, and then they are separated from the ore using a process called filtration.

Smelting is a process that melts ores to extract metals. The ore is heated to a high temperature, which causes the metal to melt and separate from the other minerals in the ore. The molten metal is then poured into molds to create ingots or other shapes.

Refining is a process that removes impurities from metals. The metal is melted and then mixed with a solution of acids or bases. The impurities dissolve in the solution, and then they are separated from the metal using a process called electrolysis.

Casting is a process that uses molten metal to create objects. The molten metal is poured into molds, which give the objects their shape. Once the metal cools and hardens, the objects are removed from the molds.

Forging is a process that uses heat and pressure to shape metal. The metal is heated to a high temperature, and then it is hammered or pressed into the desired shape.

Rolling is a process that uses pressure to flatten metal. The metal is passed through rollers, which flatten it to the desired thickness.

Extrusion is a process that uses pressure to force metal through a die. The metal is forced through the die, which gives it the desired shape.

Powder metallurgy is a process that uses powdered metal to create objects. The powdered metal is mixed with a binder, and then it is pressed into the desired shape. The object is then heated, which causes the binder to burn away and the metal to fuse together.

Machining is a process that uses tools to cut metal. The metal is held in place, and then a tool is used to cut it into the desired shape.

Heat treatment is a process that changes the properties of metal. The metal is heated to a high temperature, and then it is cooled in a controlled manner. This changes the microstructure of the metal, which can improve its strength, toughness, or other properties.

Joining is a process that connects two pieces of metal. The pieces of metal are joined using a variety of methods, such as welding, soldering, or brazing.

Finishing is a process that improves the appearance of metal. The metal is polished, painted, or coated with a protective finish.

Inspection is a process that checks the quality of metal. The metal is inspected for defects, such as cracks or flaws.

Testing is a process that determines the properties of metal. The metal is tested for its strength, toughness, or other properties.

Quality control is a process that ensures that metal meets the required specifications. The metal is inspected and tested to ensure that it meets the required quality standards.

Disposal is a process that removes metal from the Environment. The metal is recycled, or it is disposed of in a landfill or incinerator.

What is refining?

Refining is the process of purifying a substance, usually by removing impurities.

What are the different types of refining?

There are many different types of refining, depending on the substance being refined and the impurities to be removed. Some common types of refining include:

  • Metallurgical refining: This type of refining is used to purify metals, such as gold, silver, and copper. It involves a series of steps, including crushing the ore, heating it, and then dissolving the metal in a solution. The metal is then precipitated out of the solution and purified.
  • Chemical refining: This type of refining is used to purify chemicals, such as gasoline, diesel fuel, and kerosene. It involves a series of steps, including distillation, which separates the different components of the mixture based on their boiling points.
  • Petrochemical refining: This type of refining is used to purify petroleum products, such as gasoline, diesel fuel, and kerosene. It involves a series of steps, including distillation, which separates the different components of the mixture based on their boiling points.

What are the benefits of refining?

There are many benefits to refining, including:

  • Improved quality: Refining can improve the quality of a substance by removing impurities. This can make the substance more useful and valuable.
  • Increased safety: Refining can increase the safety of a substance by removing impurities that could be harmful to humans or the environment.
  • Reduced environmental impact: Refining can reduce the environmental impact of a substance by removing impurities that could pollute the air, water, or land.

What are the drawbacks of refining?

There are some drawbacks to refining, including:

  • Cost: Refining can be a costly process.
  • Energy consumption: Refining can consume a lot of energy.
  • Environmental impact: Refining can have an environmental impact, such as Air Pollution and Water Pollution.

What are the latest developments in refining?

There are many recent developments in refining, including:

  • New technologies: New technologies are being developed to improve the efficiency and effectiveness of refining.
  • Sustainable refining: There is a growing focus on sustainable refining, which uses methods that reduce the environmental impact of refining.
  • Green refining: Green refining is a type of sustainable refining that uses RENEWABLE ENERGY and environmentally friendly chemicals.

What are the future trends in refining?

The future trends in refining are likely to include:

  • Increased demand for refined products: The demand for refined products is expected to increase in the future, due to Population Growth and Economic Development.
  • Rising costs of energy and raw materials: The costs of energy and raw materials are expected to rise in the future, which will make refining more expensive.
  • Increased focus on sustainability: There is a growing focus on sustainability in the refining Industry, which will lead to the development of new technologies and methods that reduce the environmental impact of refining.

Question 1

Which of the following is not a metal?

(A) Gold
(B) Silver
(C) Copper
(D) Iron
(E) Wood

Answer

(E) Wood is not a metal. It is a type of organic material that is made up of cellulose, hemicellulose, and lignin.

Question 2

Which of the following is the most abundant metal in the Earth’s crust?

(A) Aluminum
(B) Iron
(C) Copper
(D) Zinc
(E) Lead

Answer

(A) Aluminum is the most abundant metal in the Earth’s crust. It makes up about 8% of the Earth’s crust by weight.

Question 3

Which of the following is the most common Alloy of iron?

(A) Steel
(B) Brass
(C) Bronze
(D) Pewter
(E) Stainless steel

Answer

(A) Steel is the most common alloy of iron. It is made by adding carbon to iron.

Question 4

Which of the following is the process of extracting a metal from its ore?

(A) Refining
(B) Metallurgy
(C) Smelting
(D) Leaching
(E) Roasting

Answer

(C) Smelting is the process of extracting a metal from its ore. It is done by heating the ore to a high temperature and then adding a reducing agent.

Question 5

Which of the following is the process of purifying a metal?

(A) Refining
(B) Metallurgy
(C) Smelting
(D) Leaching
(E) Roasting

Answer

(A) Refining is the process of purifying a metal. It is done by removing impurities from the metal.

Question 6

Which of the following is the study of metals and their properties?

(A) Metallurgy
(B) Chemistry
(C) Physics
(D) Engineering
(E) Biology

Answer

(A) Metallurgy is the study of metals and their properties. It is a branch of engineering that deals with the extraction, processing, and purification of metals.

Question 7

Which of the following is a type of iron ore?

(A) Hematite
(B) Magnetite
(C) Limonite
(D) All of the above

Answer

(D) All of the above are types of iron ore. Hematite is the most common type of iron ore. Magnetite is a type of iron ore that is attracted to magnets. Limonite is a type of iron ore that is found in swamps and bogs.

Question 8

Which of the following is a type of copper ore?

(A) Chalcopyrite
(B) Bornite
(C) Copper glance
(D) All of the above

Answer

(D) All of the above are types of copper ore. Chalcopyrite is the most common type of copper ore. Bornite is a type of copper ore that is found in Chile. Copper glance is a type of copper ore that is found in the United States.

Question 9

Which of the following is a type of gold ore?

(A) Gold nugget
(B) Gold dust
(C) Gold bearing quartz
(D) All of the above

Answer

(D) All of the above are types of gold ore. Gold nugget is a type of gold ore that is found in its natural state. Gold dust is a type of gold ore that is found in small particles. Gold bearing quartz is a type of gold ore that is found in quartz.

Question 10

Which of the following is a type of silver ore?

(A) Argentite
(B) Cerargyrite
(C) Galena
(D) All of the above

Answer

(D) All of the above are types of silver ore. Argentite is the most common type of silver ore. Cerargyrite is a type of silver ore that is found in Mexico. Galena is a type of silver ore that is found in lead ores.