Select the correct statement(s) about calcination and roasting.

ARoasting is generally done above the melting point of the ore, so that the product is a molten mass
BCalcination is carried out in a plentiful supply of air so that the ore is oxidised
CDuring roasting of an ore containing arsenic and sulphur impurities, these are removed largely as volatile $As X_{2} O X_{3}$ and $SO X_{2}$
DHeating dolomite, $CaCO X_{3} \cdot MgCO X_{3}$ , in the absence of air to give $CaO$ , $MgO$ and $CO X_{2}$ is calcination

Answer: C, D

Calcination is heating below the melting point in little or no air, to drive off

CO X_{2}

or water, so dolomite is a typical example (true). Roasting heats the ore in excess air, again below its melting point, and oxidises volatile impurities such as As and S to

As X_{2} O X_{3}

and

SO X_{2}

(true). The statements that calcination uses plentiful air and that roasting melts the ore are both false.

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Select the correct statement(s) about calcination and roasting.

Answer: C, D

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