Precipitation of sparingly soluble materials from two aqueous ionic solutions is considered. It is well known that the flow conditions in the system can affect particle size distribution and particle morphology. In the paper, three problems related to interactions between hydrodynamics (turbulent flow) and the precipitation process are considered, namely, effects of mixing on crystal size using computational fluid dynamics (CFD), relation between turbulent diffusion of fluids and solid particles, and the problem of aggregation kernel for small particles.