Occurrence and Principles of Extraction of Zinc

There are 75 parts per million of zinc in the earth’s crust. Zinc is the 24th most common element in the earth’s crust. It ranges from 5 to 770 parts per million in soil, with 64 parts per million. 

There are many types of zinc ore, but the most common is sphalerite (zinc blende), made of zinc and sulfur. That can take zinc out of the zinc blende by following these steps:

• Froth flotation process

• Roasting

The froth flotation process is the most important part of the extraction of zinc. In this article, we will discuss the occurrence and principles of extraction of zinc.

Occurrence of Zinc

Zinc is in group IIb of the periodic table. An atom of zinc has 30 electrons; therefore, it is called zinc. A zinc atom has an atomic number of 30. Its mass is 65. Zinc has a sign that looks like this: Zn.

There’s a lot of zinc on the earth’s surface, but it doesn’t exist in its pure form. Many different minerals can be used to get zinc, like smithsonite, wurtzite, hemimorphite, sphalerite, etc. Sphalerite is the main source of zinc as it has 60% of zinc.

Zinc Mining

There are many different ways to get zinc from the earth, and one way is through mining. In zinc mining, zinc minerals in the ore are the main thing that the mine makes. Zinc ore often comes with minerals like lead and silver as byproducts.

Zinc blende, also known as zinc sulphide, is the most common ore used to make zinc (ZnS). Zinc has been harder to get than other metals in the past because it doesn’t melt at the same temperature as other metals, like iron. Since zinc has a low boiling point, it will lose it as the exhaust gases escape. Getting the most out of zinc-blende needs to be highly concentrated.

Obtaining zinc from ore is the preferred method of extraction. The froth flotation process is the name given to it.

Froth Flotation Process

People use this process to eliminate the “gangue” found with sulphur ore. A paste is formed by grinding up ore and adding water. The froth flotation process relies heavily on these components. The froth stabilisers and collectors are what make it all happen. It’s possible to make the metal part of the ore more frothy by adding “collectors” (fatty acids, pine oils, and so on). To keep the froth in place, we use froth stabilisers (anilines, cresols, and so on). To properly clean the metal, large quantities of water and oil are required. Paddles and air move the suspension around to create froth. The metal is immediately removed from the surface and dried.

Concentrated Ore is a Source of Metal

Let’s look at the next step in getting zinc out of the ground. Ore is ground into small pieces and then floated in a stream of air that gets faster and faster. It also turns the zinc blende into ZnO, which is a lot more violent. 

2ZnS +3O2 →2ZnO + 2SO2 is the reaction taking place here.

If you want, you can add coke and grind it into small pieces before heating it in fire clay containers at 1673 K. This process is called the Belgian process, wherein the zinc oxide turns into pure zinc. You can see how this reaction works: The carbon from coke is what reduces this. The reaction at the end of the extraction of zinc is called roasting.

2ZnO + C  →2Zn + CO₂

A lot of non-volatile impurities are left behind when zinc is made. These include lead, cadmium, and iron. For zinc to boil, it needs to be at a temperature of 1180 K, which is a long way back. The zinc vapours have to be collected and cooled down to make zinc from this gas. Spelter is the name given to a metal that is very old and raw. It can be even purer through fractional distillation.

Zinc can be mixed with a lot of other metals. It can be mixed with nickel, bronze, silver, soft electrical and brass, solder with zinc, etc. Zinc is made in huge quantities, and a lot of it is used to galvanise iron so that it doesn’t rust.

Properties of Zinc

Zinc is a shiny, crystalline, brittle, blueish-silver, or white metal that can be hard or soft. When it comes into contact with air, it gets dirty. Many other elements can react with zinc to make elements like the oxides of zinc.

Conclusion

There are many different ways to get zinc from the earth, and one way is zinc mining. 

Sphalerite is the main source of Zinc because it has 60% of zinc. Zinc blende, also known as zinc sulphide, is the most common ore used to make zinc (ZnS). The extraction of zinc is called roasting. Silver, nickel, brass, bronze, and soft solder are all metals that can mix with zinc. Most of the time, the froth flotation process is used to get rid of gangue from sulphide ores