One embodiment provides for a liquids/solids reaction vessel configured to contain a mixture of at least one liquid and at least one solid. The vessel includes a closed perimeter wall defined by an effective height, and a bottom connected to the closed perimeter wall to thereby define a vessel volume configured to contain the mixture. The reaction vessel further includes a solids extraction system located in at least one of the bottom or in the perimeter wall proximate the bottom. The effective height is selected to produce a pressure proximate the bottom of the reaction vessel selected to eject the at least one solid through the solids extraction system under the influence of gravity alone. The effective height can be further selected to cause an increase in a reaction rate between the at least one liquid and the at least one solid.