The key difference between calcination and sintering is that calcination is the heating of metal ore to remove impurities, whereas sintering is the heating of metal ore to weld together small particles of a metal.
Calcination and sintering are two different pyrometallurgical processes. However, both these processes involve the heating of a metallic material to a temperature that is below the melting point of that metal.
CONTENTS
1. Overview and Key Difference
2. What is Calcination
3. What is Sintering
4. Side by Side Comparison – Calcination vs Sintering in Tabular Form
5. Summary
What is Calcination?
Calcination is a pyrometallurgical process of heating a metal ore in the presence of limited air or oxygen. In this process, we need to heat the ore to a temperature below its melting point. The process is useful mainly to remove volatile impurities. Furthermore, the name calcination comes from a Latin name due to its major application – the heating of calcium carbonate ores.
Figure 01: Calciner
Calcination is done in a reactor, which is a cylindrical structure; we call it the calciner. In this reactor, the calcination is done under controlled conditions. Carbon dioxide is produced and released during the calcination and the calcium carbonate is converted into calcium oxide. This process is done mainly to remove volatile impurities. However, sometimes a furnace is used for the calcination because it involves heating a substance to very high temperatures.
A typical example of calcination is the production of lime from limestone. In this process, limestone is given a high temperature that is enough to form and release carbon dioxide gas. Lime is produced in an easily powdered condition.
What is Sintering?
Sintering is a pyrometallurgical process in which small particles of metal are welded together. It is done by applying a heat that is below the melting point of the metal. The application of heat removes internal stresses from certain materials. Furthermore, this process is mainly useful in manufacturing steel. The uses of sintering process include the formation of complex shapes, production of alloys and the ability to work easily with metals having high melting points.
In the manufacturing process, we have to use a bed of powdered iron from iron ore. This iron has to be mixed with coke before using. Then the bed of iron is ignited using a gas burner. The burned portion is then passed along a travelling grate. Here, we have to draw air through the grate in order to initiate a combustion reaction. Then a very high heat is generated, which causes tiny particles of the metal to form lumps. These lumps are suitable to be burnt in a blast furnace in order to form steel. In addition, the sintering process is important in the manufacture of ceramic and glass as well.
What is the Difference Between Calcination and Sintering?
Calcination and sintering are two different pyrometallurgical processes. The key difference between calcination and sintering is that calcination is the heating of metal ore to remove impurities, whereas sintering is the heating of metal ore to weld together small particles of a metal. The outcome of calcination is the removal of impurities from a metal ore while for sintering it is the welding of particles of metal to get one piece.
Below tabulation summarizes the difference between calcination and sintering.
Summary – Calcination vs Sintering
Calcination and sintering are two different pyrometallurgical processes. The key difference between calcination and sintering is that calcination is the heating of metal ore to remove impurities, whereas sintering is the heating of metal ore to weld together small particles of a metal.
Reference:
1. “Calcination.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 4 Oct. 2016, Available here.
2. Helmenstine, Anne Marie. “Roasting Definition in Chemistry.” ThoughtCo, Feb. 11, 2020, Available here.
Image Courtesy:
1. “LDLimeShaftKilnBasic” By LinguisticDemographer – Originally from en.wikipedia; description page is/was here., (Public Domain) via Commons Wikimedia
2. “Factory and industrial management (1891) (14594947629)” By Internet Archive Book Images – (Public Domain) via Commons Wikimedia