Why does hydrated lime settle when the agitation stops? Why doesn it all go into solution?
Hydrated lime (calcium hydroxide) is only slightly soluble in water. The particle size is very small, so agitation of the solution will keep the particles suspended until the agitation is stopped. The small size of the particle in suspension is responsible for the reactivity of hydrated lime. Since the particle size is so small, the surface area of the hydrated lime exposed to water increases dramatically. As hydrated lime (calcium hydroxide) in solution is used up in reactions, additional lime goes in solution to replace it.