What is the name of the conical tank where the softening reaction occurs?

The correct answer is the pellet reactor, which is a specific type of conical tank used in water softening processes. In this tank, the softening reaction occurs when calcium and magnesium ions in the water are replaced with sodium ions, typically facilitated by the addition of lime and soda ash. The conical shape of the reactor allows for effective mixing and retention time, ensuring that the chemical reactions can take place efficiently. The reactor promotes the growth of calcium carbonate crystals, which eventually form pellets that can be removed.

This process is crucial in water treatment as it helps in reducing hardness in water, making it more suitable for consumption and use in various applications. The functionality of a pellet reactor is vital to achieving optimal softening results, making it an essential component in modern water treatment facilities.