In relation to metal production, explain any three of the following furnace terms: Tapping hole, Charge, Refractory lining, Slag - Leaving Cert Engineering - Question 2 - 2022

The charge refers to the materials that are introduced into the furnace for processing. This can include various feedstocks such as metallic scrap (like iron and steel), together with other materials such as coke and limestone. The charge undergoes chemical transformations within the furnace to produce molten metal, which is later tapped out for further processing.

The refractory lining is a layer of material inside the furnace that acts as an insulator against high temperatures. It is designed to protect the structural integrity of the furnace and maintain efficiency by minimizing heat loss. Depending on the furnace design, materials such as firebrick or ceramic may be used for the refractory lining to withstand the harsh conditions of metal production.

I will describe the operation of a Blast Furnace:

A blast furnace is utilized for producing iron from iron ore and operates on several key principles. The furnace is filled with alternating layers of iron ore, coke, and limestone. Coke serves as both fuel and a reducing agent, while limestone acts as a flux to remove impurities.

When the furnace is operating, hot air is blown through tuyeres at the bottom, igniting the coke and generating high temperatures. This causes the coke to react with the oxygen in the iron ore, resulting in molten iron at the bottom, which is periodically tapped off.

As the iron ore is reduced, slag is formed and rises to the top, where it floats on the molten iron. The slag is periodically removed through the tapping hole, along with the molten iron. This process allows for continual input of charge materials and extraction of finished product.

Here’s a labelled diagram illustrating a typical blast furnace operation:

(Note: Replace this link with an actual diagram link if available).