Question

In manufacture of iron from Haematite, limestone is added is act as:
A. Slag
B. An oxidising agent
C. A reductant
D. Flux

Answer 1

Hint: The process by which iron is extracted from the ore hematite is actually smelting. In smelting a reducing agent is used which reduces the metal from its oxide to form molten metal.

Complete Step by Step Answer:
The process of smelting involves heating and melting of the ore, mainly oxide ores. In this process a metal oxide ore is heated and melted in presence of a reducing agent to form fused or molten metal. Here the reducing agent reduces the metal oxide to fused metal and oxidises itself to oxide.

In the process metallurgy, a flux is defined as a chemical that acts as a cleaning agent, flowing agent, or purifying agent Flux is a reducing agent that reduces metal from its ore. Limestone is actually calcium carbonate. This calcium carbonate reduces the metal oxide to form molten iron metal. Thus it acts as a flux.
Thus the correct option is D.

Note: Hematite is an ore of iron. It is actually ferrous oxide. Iron metal is extracted from hematite or iron oxide by smelting in molten state.