Crystallization from mixed salts solutions

Crystallization is a fundamental physico-chemical process that is omnipresent in everyday life, from the simple crystallization of table salt by evaporation of seawater and the freezing of a bottle of water in the freezer, to the design of new chemical compounds for wide range of applications. Specific crystal morphologies are desired in various applications for their distinct properties or functionality. The principles of crystallization are also important in our understanding of the natural world: on a planetary scale, in geology in the formation of rocks on Earth or other planets such as Mars.
In this thesis, we have shown that by carefully selecting salt mixtures and the way the salts are made to precipitate we can control the shape, size, and surface characteristics of the emerging crystals. We employ different crystallization strategies by controlling the evaporation rate or temperature and use antisolvent crystallization to obtain rapid quenches.
We show how the interfacial properties of the emerging crystals of NaCl dictate the location of the nucleation and growth during evaporation leading to pendant crystals floating at the liquid/air interface till macroscopic sizes. Subsequently, we show that is it possible to embed enough iron via solution inclusions in NaCl crystals to make fortified table salt to fight against nutritional iron deficiency (anemia).
Finally, our investigation into multicomponent salt systems led to the laboratory synthesis of new natural double salts containing Iron when using an antisolvent precipitation strategy thanks to extremely high supersaturations achieved. Finally, we report on the conditions to induce controlled spherulitic growth of salt crystals due to a novel mechanism involving the formation of a gel like system in evaporating aqueous salt mixtures containing sulfate solutions in the presence of bivalent cations.