Processes of Metallurgy

Introduction

The processes of metallurgy are focused on the production of metals, because these are not found in isolated state on the earth. However, the metals are found in crude materials with a combination of impurities and minerals. Therefore, several kind of processing techniques are essential to extract the metals. Metallurgy also includes the blending of different metals in a specific ratio for making metallic alloys.

Defining the process of Metallurgy

Metallurgy is defined as the process is used for extraction of metals from their crude state found on the earth. However, Metallurgy results in extraction of metal in its purest form. It is necessary, because when metals are found in a compound state on earth’s crust. The compound state of minerals consists of rocks, soil, sand, and limestone together with metal. Therefore, several methods have been invented for extraction of the metals within minimum time and at low cost.

However, these minerals are known as ores, added into the furnace to remove the impurities is known as flux. The impurities are also stated as gangue. Various methods for the removal of impurities from metals are noticed in metallurgy, depending on their nature as well as their impurities.

Types of Metallurgy

In chemistry, the processes of metallurgy can be segregated into three major branches, these branches include, physical metallurgy followed by extractive metallurgy, and lastly, mineral processing. Physical metallurgy solves problems in the improvement in the state of alloys of metals required in construction as well as for further manufacturing processes.

Steps in the process of Metallurgy

However, the essential steps to process the extraction of metals from minerals are stated below −

• The first step relates to the crushing as well as the grinding of the ore.

• Followed by this step, ore enrichment is done by concentrating the ores from crude phase.

• Further step of purification leads to the extraction of metals from the concentrated ores. This adds to the redefinition and purification of impure metals.

Principles followed in Metallurgy

The principles of metallurgy consists of, primary process of crushing and grinding followed by the concentration of ores. The crushing and grinding is also known as pulverization, where the ores are transformed into fine powders into a crusher. After extraction of ores using previous method, contain impurities such as, feldspar, sand, mica, and silicates and further removal of these gangues are known as dressing . This results in decrease in the concentration of ores but increase in metal concentrations.

Figure 1 − Froth Flotation

However, both the physical and chemical processes are applied for extraction of metals from their respective ores.

Physical Methods

Physical Methods refers to the traditional method of hand-picking. However, that consists of the Hydraulic Method or Levigation, where, segregation is based on the force of gravity of metals particles. There is another method known as Magnetic separation, where, impurities are magnetic in nature hence, are removed from the ore using magnets. For example, pyrolusite or $\mathrm{(MnO_{2})}$, chromite or $\mathrm{(FeO.Cr_{2}O_{3})}$, and many more are used in the extraction process.

Figure 2 − Blust furnace

The last physical method is float floatation, where the crushed ores are mixed water and along with other elements such as, oil of pine and detergents in a tank. This leads to the separation of metals and result in the extraction of the pure metal.

Figure 3 − Oxygen furnace

Chemical Methods

Chemical Methods consists of the methods of leaching and roasting. In the process of leaching, ores are treated by chemical reactions. In this process such solvents are used where impurities of the ores are soluble and removed properly in solvent medium. Roasting process is carried out by heating of concentrated ores, in presence of oxygen to extract the metals.

Importance of Metallurgy

In the present-day, metallurgy is beneficial for the advancement in the economic system as well as lesser time consuming for manufacturing metals. However, it is essential in the creation of gadgets, as well as tools that are used by humans on a daily basis.

Conclusion

In this tutorial, the focus has been given to catering to the processes that are involved in the field of metallurgy. Ores are minerals from which the metal is extracted and are used for commercial purposes. Therefore, processes of metallurgy are quite essential and used to provide benefits to industries as these processes are profitable and economical. Not only in manufacturing industries, but also the metals are required in industries for manufacturing of ornaments, cooking gadgets, and in metal alloys.

FAQs

1. What are the various processes involved in the concentration of ores?

The various processes are involved in the process of concentration of ores using, electromagnetic separation followed by froth floating, and lastly, by hydraulic washing.

2. Why is it necessary to purify the extracted metals?

It is quite a necessary process to purify the extracted metals, as most times impurities are noticed during metal extraction. The impurities include phosphorous, carbon, silicon, and many more.

However, the method used for purification completely depends on the nature of the metal and its impurities. Considering several methods for removal of impurities, the electrolytic method is the best one.

3. What is defined by smelting?

Smelting is defined as the process, where heat is applied to the ore; result in the extraction of the base metal. This process is defined as extractive metallurgy. For example, metals like Copper, Silver, Iron, and many other are extracted as base metals using this process.