Systems and methods and resulting compositions of matter including silicon solids from a mixture of silicon and water. The mixture is collected at a collection stage from at least one wafer abrasion process performed on a silicon surface having an impurity concentration ≦0.1 ppb and extracting one portion of the water from the mixture using at least one dryer stage to form a dry cake. The dry cake includes at least 99.99% silicon by weight excluding water and non-silicon species, where a concentration of water in the dry cake is between 0.05% and 1% by weight, and where a concentration of non-silicon species in the dry cake is between 0.05% and 1% by weight.