Question

A common by-product of sulfur dioxide removal from stack gases is?

1) CaO
2) CaSO₄
3) CaCO₃
4) solid S

Answer 1

The common by-product of sulfur dioxide removal from stack gases is CaSO₄ (calcium sulfate).

Step-by-step explanation:

The common by-product of sulfur dioxide removal from stack gases is CaSO₄ (calcium sulfate). In the process of removing sulfur dioxide from stack gases, a device called a scrubber is used. The scrubber blows calcium carbonate (CaCO₃) into the combustion chamber, where it decomposes into calcium oxide (CaO), also known as lime, and carbon dioxide (CO₂).

The lime then reacts with the sulfur dioxide (SO₂) to form calcium sulfite (CaSO₃). A suspension of lime is then injected into the mixture to produce a slurry, which removes the calcium sulfite and any remaining unreacted sulfur dioxide.