Crystal habit modification of sodium chloride using habit modifiers: a dive into more than 50 years of research & development on crystal habit modification of rock-salt crystals

Crystal habit modification of salt crystals has been a fascinating area of research for decades. The microscopic analysis of drops of brine evaporating in air showed crystal forms of sodium chloride other than the cube when crystal habit modifiers were added to the brine solution. Some of these additives have a marked effect on salt crystals with definite morphology. This review article covers the role of several parameters in the changes in the morphology of salt crystals. The molecular-level understanding of the crystal growth of sodium chloride crystals has been discussed. Selective crystal habit modification using crystal habit modifiers provides a strategy to generate the desired crystal shapes that may circumvent the problems associated with the salt manufacturing industries. In this review, the in-depth understanding of the role of the crystal habit modifiers in the crystallization process or crystal agglomeration has been discussed for improvement in various industrial and bio-medical applications.