Video Transcript
Which of the following substances
found inside a working blast furnace is referred to as slag? (A) CaO, (B) SiO2, (C) Fe2O3, (D)
CaSiO3, or (E) Fe3O4.
Blast furnaces are steel towers
lined with heat-resistant bricks that can be used to extract iron from its ore. Two layers form at the bottom of
the blast furnace. The bottom layer is composed of
molten iron, while the top layer, called slag, is made up of impurities. To answer the question, we want to
know which of the substances is referred to as slag. In order to figure this out, we
will need to take a closer look at some of the reactions that take place inside a
blast furnace.
In order for a blast furnace to
function effectively and efficiently, the iron ore must first be crushed, roasted,
and mixed with coke and limestone. The coke, which is primarily
composed of carbon, is used in several reactions inside of the blast furnace. These reactions help to maintain
the temperature of the blast furnace and also produce the reducing agent that
reduces the iron ore to molten iron.
Limestone is primarily composed of
calcium carbonate. The calcium carbonate is involved
in a reaction that helps to remove impurities from the iron ore. As slag is a waste product made up
of impurities, we should take a look at the reaction involving limestone. The temperature inside a blast
furnace is high enough to decompose calcium carbonate into calcium oxide and carbon
dioxide. The calcium oxide can then react
with sand impurities, which can be thought of as silicon dioxide, to produce calcium
silicate. The calcium silicate produced is
the main component of slag.
Therefore, the substance found
inside a working blast furnace that is referred to as slag is answer choice (D),
CaSiO3.
