Question

what is roasting and calcination?​

Answer 1

Answer:

Calcination is a process in which ore is heated in the absence of air or air might be supplied in limited quantity. Roasting involves heating of ore lower than its melting point in the presence of air or oxygen. Calcination involves thermal decomposition of carbonate ores.

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Answer 2

Answer:

Calcination:

The ore is heated to a high temperature below its melting point in the absence of air or in a limited supply of air. The organic matter, moisture, volatile impurities like carbon dioxide and sulphur dioxide are expelled from the ore. It makes the ore porous. For example, zinc carbonate decomposes to give zinc oxide and carbon dioxide.

Eg.- ZnCO³--Δ--> ZnO+CO²

Roasting:

Ores are heated to a high temperature below their melting point in the presence of excess air. The moisture escapes and impurities like sulphur, arsenic, phosphorous etc are oxidized to their volatile oxides. The mass becomes porous.

Eg.- S + O²---> SO²

- 4P + 5O²---> 2P²O⁵

Explanation:

FOR COMPARISON, PLEASE REFER TO THE ATTACHMENT.

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