Metallurgy 2

<<–2/”>a >h3>Metallurgy 2

Roasting

It is a process wherein the Ore is heated either alone or with some other material in excess of air below the fusion point of the ore. Usually, this method is used for sulphide ores. In roasting, definite chemical changes take place to form oxide or chloride of the Metal. Ores of metals like zinc, lead, copper and nickel, when roasted in air, are converted to their oxides. Ores of some metals like lead may get partially oxidized and converted to sulphate. In such case, it is called sulphating roasting or partial roasting. Ores of metals like silver and gold are mixed with common salt and are heated in air. They are converted to their chlorides which are easy to reduce. This type of roasting is called chlorinating roasting. The purpose of roasting is to convert the ore in a form suitable to reduce. The gaseous product of sulphide roasting, sulphur dioxide is often used to produce sulphuric acid.

Metallurgy 2

Smelting

Smelting is the basic process by which one produces workable metal from metal ores. The Minerals in copper ores are reduced to copper through mixing carbon with the ore and heating the combination to about 1,100°C. (This can be done directly with copper oxide ores. Copper sulphide ores are heated in contact with air first.) At this temperature the metal, now liquid, flows to the bottom of the furnace, and the remaining matter (slag) floats to the top, whence it is removed. (Slag usually includes large amounts of silicon and related material and produces waste heaps of glass-like or cinder-like material.) Although this sounds straightforward, in antiquity, and especially before the invention of a bellows, it was difficult to attain the necessary temperature, and the extraction of copper from slag was in fact a difficult, messy, and extremely labor-intensive project.

Smelting produces a blob of metal (called bloom) prepared for the next step. In the case of copper, that step is often casting.

Iron has a higher melting point than copper. But below its melting point iron can still become spongy and amenable to treatment by hot hammering (forging), which helps to extract some of the remaining impurities.

Refining

Metals obtained by reduction processes still contain some objectionable impurities and hence have to be refined. Refining techniques vary widely from metal to metal and also depend on the use to which a metal has to be put. Sometimes during refining some substances may have to be added to impart some desirable characteristics to the metal. In some cases a metal is refined to recover valuable by-products present as impurities. Some of the refining processes used are defined below.

By Poling

By Liquation

Readily fusible metals like Sn, Pb and Bi are refined by this method. Impure metal in the form of ingots blocks in the upper part of a sloping hearth (usually of a reverberatory furnace) maintained at a temperature slightly above the melting point of the metal. The impurities remain behind as dross while the pure metal melts and flows down into a well at the bottom of the incline.

By Cupellation

This method employed to purify silver containing lead as an impurity. The impure silver is heated in a shallow vessel made of bone-ash under a blast of air. The lead is easily oxidized to powdery lead monoxide. Most of it is carried away by the blast of air. The rest melts and is absorbed by the bone ash cupel. Pure silver is left behind. Silver itself is not oxidized under these conditions.

By Distillation

Some metals have very low melting point and soon vaporize on heating while the associated impurities remain the solid state. Zinc, mercury and arsenic are purified by this method. Vacuum distillation gives very pure product and is used in the refining of the metals of IA and IIA.

By Fractional Distillation

This process is applied for the separation of cadmium from zinc. In the metallurgy of zinc, the metal is invariably associated with cadmium. The impure zinc is mixed with powdered coke and heated when the first portion of the condensate contain cadmium while zinc is obtained in the subsequent portions.

By Electrolytic Refining

This a very convenient method for refining many impure metals. Most of the metals such as copper, silver, gold, zinc and chromium are refined electrolytically. The impure metal is made the anode and a thin sheet of the pure metal as cathode. A solution of a salt of the metal serves as the electrolyte. On passing an electric current through the electrolyte, the metal dissolves in the electrolyte by oxidation of the anode and pure metal is deposited at the cathode. The impurities present in the anode either dissolve in the electrolyte or collect below the anode as anode mud. In the electrolytic refining of copper, impurities of iron and zinc are dissolved in the electrolyte and white gold, platinum and silver are left behind as anode mud.

Van-Arke Method

This is used for getting ultra pure metals. The principle involved is to convert the metal to a volatile unstable compound and to subsequently decompose it to give the pure metal. The impurities present should be such as not to be affected. Metals like titanium, zirconium etc. are purified by using this method.

Ti(s) + 2I₂(g) Ti I₄(g)
TiI₄(g) Ti(s) + 2I₂(g)
Pure

Zone- Refining

Meals of very high purity can be obtained by this method by removing an impurity, which shows difference in solubility of the liquid and solid states of the metal. A circular heater is fitted around a rod of impure metal and is slowly moved down the rod. At the heated zone, the rod mellts and as the heater passes on, pure metal crystallizes while impurities pass into the adjacent molten part. In this way, the impurities are swept over one end of the rod, which is finally discarded. The heater may have to be moved from one end to the other more than once. Ge, Si and Ga are used as semiconductors are refined in this manner; gallium-arsenide and indium-antimonide are also zone refined.

Chromatography (Ion Exchange Method)

Chromatography is based on the differential adsorption of the various components in a mixture on a suitable adsorbent. In its various forms like column chromatography, TLC (Thin Layer Chromatography), GLC (Gas Liquid Chromatography), Ion-exchange chromatography and Paper chromatography, it is widely used for the separation of mixtures and concentration, identification and refining of materials.

Metallurgy is the science of metals and their alloys. It is a broad field that encompasses the extraction and processing of metals, as well as the study of their properties and applications. Metallurgy is essential to the modern world, as metals are used in a wide range of products, from cars and buildings to electronics and medical devices.

One of the most important concepts in metallurgy is the phase diagram. A phase diagram is a graphical representation of the equilibrium between different phases of a material, such as solid, liquid, and gas. Phase diagrams can be used to predict the behavior of a material under different conditions, such as temperature and pressure.

Solidification is the process by which a liquid metal transforms into a solid. The solidification process is important because it can affect the properties of the final product. For example, the rate of solidification can affect the grain size of the metal, which can in turn affect its strength and ductility.

Casting is a manufacturing process in which a liquid metal is poured into a mold to create a desired shape. Casting is a versatile process that can be used to produce a wide range of products, from small jewelry items to large industrial castings.

Wrought processing is a group of manufacturing processes that are used to shape metals into desired forms. Wrought processing methods include rolling, forging, and extrusion. Wrought processing can be used to produce a wide range of products, from sheet metal to structural beams.

Heat treatment is a process that is used to alter the properties of a metal. Heat treatment can be used to improve the strength, toughness, or ductility of a metal. Heat treatment is a complex process that requires careful control of temperature and time.

Deformation processing is a group of manufacturing processes that are used to change the shape of a metal by applying force. Deformation processing methods include rolling, forging, and extrusion. Deformation processing can be used to produce a wide range of products, from sheet metal to structural beams.

Corrosion is the deterioration of a metal due to chemical or electrochemical reactions with its Environment. Corrosion can cause metals to lose their strength and can lead to failure of structures and equipment. Corrosion is a major problem in many industries, and it is estimated to cost the global economy billions of dollars each year.

Fatigue is the progressive failure of a material under repeated loading. Fatigue is a major cause of failure in many engineering structures, such as bridges and aircraft. Fatigue can be prevented by designing structures to avoid Stress concentrations and by using materials that are resistant to fatigue.

Fracture is the separation of a material into two or more pieces. Fracture can occur due to a variety of factors, including stress, corrosion, and fatigue. Fracture is a major cause of failure in many engineering structures, and it is important to understand the factors that can lead to fracture in order to prevent it.

Welding is a manufacturing process that is used to join two or more pieces of metal together. Welding is a versatile process that can be used to join a wide range of metals, and it is used in a variety of industries, including construction, manufacturing, and transportation.

Joining is a manufacturing process that is used to connect two or more pieces of material together. Joining methods include welding, brazing, and soldering. Joining is a critical process in many industries, and it is used to produce a wide range of products, from cars and buildings to electronics and medical devices.

Surface engineering is a group of manufacturing processes that are used to improve the properties of the surface of a metal. Surface engineering methods include coating, plating, and anodizing. Surface engineering can be used to improve the corrosion resistance, wear resistance, or appearance of a metal.

Materials selection is the process of choosing the right material for a particular application. Materials selection is a complex process that requires consideration of a variety of factors, including the properties of the material, the cost of the material, and the manufacturing process.

Design for manufacturability is the process of designing a product so that it is easy and economical to manufacture. Design for manufacturability is a critical process in many industries, and it can save companies a significant amount of Money.

Quality control is the process of ensuring that a product meets the desired quality standards. Quality control is a critical process in many industries, and it can help to prevent defects and improve the quality of products.

Recycling and Waste Management are the processes of collecting and processing materials that would otherwise be thrown away. Recycling and waste management are important environmental issues, and they can help to conserve Resources and reduce pollution.

What is metallurgy?

Metallurgy is the science, technology, and art of extracting metals from ores and using them to make useful objects.

What are the different types of metallurgy?

There are two main types of metallurgy: extractive metallurgy and physical metallurgy. Extractive metallurgy is the process of extracting metals from ores, while physical metallurgy is the study of the properties of metals and their alloys.

What are the different stages of metallurgy?

The different stages of metallurgy are:

Ore mining: The ore is mined from the ground.
Ore beneficiation: The ore is processed to remove impurities.
Smelting: The ore is melted and the metal is extracted.
Refining: The metal is purified.
Casting: The metal is cast into a desired shape.
Forging: The metal is shaped by hammering or rolling.
Machining: The metal is shaped by cutting.
Heat treatment: The metal is heated to change its properties.
Finishing: The metal is coated or polished to give it a desired finish.

What are the different types of metals?

There are many different types of metals, but some of the most common include:

Iron
Steel
Copper
Aluminum
Nickel
Zinc
Tin
Lead
Gold
Silver
Platinum

What are the different types of alloys?

An Alloy is a mixture of two or more metals. Alloys are often used to improve the properties of metals, such as their strength, hardness, or corrosion resistance. Some common alloys include:

Steel: A mixture of iron and carbon.
Brass: A mixture of copper and zinc.
Bronze: A mixture of copper and tin.
Stainless steel: A mixture of iron, chromium, and nickel.

What are the different applications of metallurgy?

Metallurgy has many applications, including:

Construction: Metals are used to build buildings, bridges, and other structures.
Transportation: Metals are used to make cars, trains, and airplanes.
Electronics: Metals are used to make computers, cell phones, and other electronic devices.
Machinery: Metals are used to make machines, tools, and other equipment.
Packaging: Metals are used to make cans, bottles, and other packaging materials.
Jewelry: Metals are used to make jewelry, such as rings, necklaces, and earrings.

What are the environmental impacts of metallurgy?

The mining and processing of metals can have a significant impact on the environment. Mining can lead to deforestation, Soil erosion, and Water Pollution. The processing of metals can also release pollutants into the air and water.

What are the safety hazards of metallurgy?

Metallurgy can be a dangerous occupation. Workers in the metallurgy Industry are exposed to a variety of hazards, including:

Fire and explosions
Chemical exposure
Noise exposure
Physical hazards, such as falls and machinery accidents

What are the future trends in metallurgy?

The future of metallurgy is likely to be driven by the need for more sustainable materials. New technologies, such as 3D printing, are also likely to have a significant impact on the metallurgy industry.

What is the name of the process of extracting metal from its ore?
(A) Smelting
(B) Refining
(C) Casting
(D) Forging
What is the name of the process of shaping metal into a desired form?
(A) Smelting
(B) Refining
(C) Casting
(D) Forging
What is the name of the process of heating metal to a high temperature and then hammering it into shape?
(A) Smelting
(B) Refining
(C) Casting
(D) Forging
What is the name of the process of heating metal to a high temperature and then pouring it into a mold to create a desired shape?
(A) Smelting
(B) Refining
(C) Casting
(D) Forging
What is the name of the process of removing impurities from metal?
(A) Smelting
(B) Refining
(C) Casting
(D) Forging
What is the name of the process of heating metal to a high temperature and then allowing it to cool slowly to create a desired shape?
(A) Annealing
(B) Hardening
(C) Tempering
(D) Quenching
What is the name of the process of heating metal to a high temperature and then rapidly cooling it to create a desired shape?
(A) Annealing
(B) Hardening
(C) Tempering
(D) Quenching
What is the name of the process of heating metal to a high temperature and then allowing it to cool slowly to increase its strength?
(A) Annealing
(B) Hardening
(C) Tempering
(D) Quenching
What is the name of the process of heating metal to a high temperature and then rapidly cooling it to increase its hardness?
(A) Annealing
(B) Hardening
(C) Tempering
(D) Quenching
What is the name of the process of heating metal to a high temperature and then allowing it to cool slowly to increase its toughness?
(A) Annealing
(B) Hardening
(C) Tempering
(D) Quenching