Question

The process of heating an ore in the absence of air below its melting point is known as _________.

• A. calcination
• B. roasting
• C. smelting
• D. poling

Answer 1

Answer: (A)

calcination

Calcination is the process in which concentrated ore is heated to a high temp (just below its fusion temp) in the absence of air.
Hydrated ores convert into oxides-
$A{l}_2{O}_3.2H_{2}O\stackrel{\Delta }{\to }A{l}_2{O}_3+2H_{2}O$
$F{e}_2{O}_3.3H_{2}O\stackrel{\Delta }{\to }F{e}_2{O}_3+3H_{2}O$
$Roasting$ is the process in which air is passed while heating the concentrated ore below its melting point.

$Smelting$ is a metallurgical process in which less electropositive metal ore such as $PbO$, $C{r}_2{O}_3$ are reduced to free metal using the powerful reducing agent like Al, C, CO etc.
Metals like Cu and Tin are separated from their respective oxides by $poling$ process using green bamboo stick.

Option A is correct.