Roasting vs. Calcination — What's the Difference?
By Tayyaba Rehman & Urooj Arif — Updated on May 7, 2024
Roasting involves heating ore in the presence of excess air to extract metal, whereas calcination involves heating an ore in limited or no air to remove volatile substances.
Difference Between Roasting and Calcination
Table of Contents
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Key Differences
Roasting is a metallurgical process where ore is heated in the presence of excess air or oxygen. This process is primarily used to convert sulfide ores into oxides or to remove impurities like sulfur, arsenic, and antimony through oxidation. Calcination, however, involves heating an ore or other solid in limited or no air. This process is employed to drive off volatile substances like moisture or carbon dioxide, converting carbonates and hydroxides into oxides.
Roasting often takes place at temperatures above the melting point of impurities to ensure complete removal. Calcination is generally conducted at lower temperatures than roasting and focuses on decomposing carbonates or hydroxides.
Roasting typically requires high temperatures and results in gaseous byproducts that are either collected or treated for pollution control. Calcination produces gaseous byproducts like water vapor or carbon dioxide.
Roasting is mostly used for sulfide ores like copper or zinc, whereas calcination is used for carbonate ores like limestone.
Comparison Chart
Air/Oxygen Requirement
Excess air or oxygen
Limited or no air
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Purpose
Convert sulfides to oxides
Decompose carbonates/hydroxides
Temperature
High
Moderate
Gaseous Byproducts
Sulfur dioxide, arsenic oxides
Water vapor, carbon dioxide
Common Ores Processed
Sulfide ores (copper, zinc)
Carbonate ores (limestone)
Compare with Definitions
Roasting
The process of heating an ore with excess air to produce oxides.
The roasting of zinc sulfide produced zinc oxide and sulfur dioxide.
Calcination
A sedimentary rock composed mainly of calcium carbonate.
Limestone is heated during calcination to produce lime.
Roasting
An ore that contains a metal bound to sulfur.
Copper sulfide ore requires roasting before smelting.
Calcination
The process of heating an ore in limited air to drive off volatile components.
The calcination of limestone results in quicklime and carbon dioxide.
Roasting
Heating ore with air to form oxides.
Oxidizing roasting is used to convert lead sulfide into lead oxide.
Calcination
An ore containing a metal carbonate compound.
Calcium carbonate is a common carbonate ore used in cement production.
Roasting
Roasting is a cooking method that uses dry heat where hot air covers the food, cooking it evenly on all sides with temperatures of at least 150 °C (300 °F) from an open flame, oven, or other heat source. Roasting can enhance the flavor through caramelization and Maillard browning on the surface of the food.
Calcination
The breakdown of a chemical compound into simpler substances.
Calcination causes the decomposition of calcium carbonate into calcium oxide.
Roasting
To cook with dry heat, as in an oven or near hot coals.
Calcination
Chemical breakdown due to heating.
Thermal decomposition of magnesium carbonate releases carbon dioxide.
Roasting
To dry, brown, or parch by exposing to heat.
Calcination
Calcination refers to heating (thermal treatment of) a solid chemical compound (e.g. carbonate ores) to high temperatures in absence or limited supply air or oxygen (O2), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition.The root of the word calcination refers to its most prominent use, which is to remove carbon from limestone through combustion to yield calcium oxide (quicklime).
Roasting
To expose to great or excessive heat.
Calcination
To heat (a substance) to a high temperature but below the melting or fusing point, causing loss of moisture or volatile impurities, reduction or oxidation, and the decomposition of carbonates and other compounds.
Roasting
(Metallurgy) To heat (ores) in a furnace in order to dehydrate, purify, or oxidize before smelting.
Calcination
To convert (liquid material, especially radioactive wastes) to granular solids by drying at very high temperatures.
Roasting
To ridicule or criticize harshly.
Calcination
To be calcined.
Roasting
To honor at or subject to a roast.
Calcination
A substance produced by calcining.
Roasting
To cook food in an oven.
Calcination
The process of calcining: heating a substance to a high temperature, but below its melting point, to bring about thermal decomposition.
Roasting
To undergo roasting.
Calcination
The act or process of disintegrating a substance, or rendering it friable by the action of heat, esp. by the expulsion of some volatile matter, as when carbonic and acid is expelled from carbonate of calcium in the burning of limestone in order to make lime.
Roasting
Something roasted.
Calcination
The act or process of reducing a metal to an oxide or metallic calx; oxidation.
Roasting
A cut of meat suitable or prepared for roasting.
Calcination
The conversion of metals into their oxides as a result of heating to a high temperature
Roasting
The act or process of roasting.
Roasting
The state of being roasted.
Roasting
Harsh ridicule or criticism.
Roasting
A facetious tribute, as at a banquet, in which the honoree is alternately praised and insulted.
Roasting
Roasted
Roast duck.
Roasting
Present participle of roast
Roasting
(colloquial) Very hot.
The day started out cool, but by noon it was roasting.
Roasting
The act by which something is roasted.
Roasting
(colloquial) A rebuke or reprimand (usually from the recipient's point of view).
My boss gave me a roasting for last month's sales figures.
Common Curiosities
What is roasting in metallurgy?
Roasting is heating an ore in excess air to convert sulfides into oxides.
What ores are processed through calcination?
Carbonate ores, such as limestone and dolomite, are processed through calcination.
How does roasting differ from calcination?
Roasting involves heating in excess air to oxidize, while calcination involves limited air to decompose.
What byproducts are produced during calcination?
Calcination typically releases water vapor or carbon dioxide.
What byproducts are produced during roasting?
Roasting often produces sulfur dioxide, arsenic oxides, or antimony oxides.
Can calcination convert sulfides into oxides?
No, calcination is used primarily to remove volatile compounds, not to convert sulfides.
Why is excess air needed in roasting?
Excess air ensures complete oxidation of the ore, removing impurities.
What ores are processed through roasting?
Sulfide ores, such as copper and zinc, are processed through roasting.
What is a typical temperature range for calcination?
Calcination temperatures range from 800°C to 1000°C, depending on the ore.
What is calcination in metallurgy?
Calcination is heating an ore in limited or no air to remove volatile substances.
What is quicklime, and how is it made?
Quicklime is calcium oxide, produced by calcining limestone.
Is roasting necessary before smelting?
Roasting is necessary for sulfide ores to convert them into oxides before smelting.
What is an example of a hydroxide ore?
Bauxite, containing aluminum hydroxide, is a hydroxide ore processed through calcination.
What is thermal decomposition?
Thermal decomposition is the breakdown of a compound by heating.
Can roasting produce toxic byproducts?
Yes, roasting sulfides can release toxic gases like sulfur dioxide or arsenic oxides.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
