Is an Ice/Water Mixture Preferred Over Pure Ice in the Crystallization Process?

[Soaring Crane]

In the crystallization process after gravity filtration is carried out, a mixture of ice and water is sometimes used as a bath instead of just ice. I know that the ice/water bath can be used to cool the filtrate to around 0 C while just crushed ice or an ice-salt bath may cool the filtrate to below 0 C. An ice/water mixture instead of pure ice is used so that the solution does not ultimately freeze?? (Are there any examples where one is preferred over another?)

Thank you.

 

[chemisttree]

It is usually because there is better contact between the liquid and the flask in an ice/water bath. An ice bath would only contact the flask in spots.

 

[JGM_14]

sometimes they add salts to the icewater bath to get it colder around -3C and the better efficency at cooling because more surface is contacted
it depends what application is used but the freezing is not usually a problem unless you have a pure liquid with a higher freezing point. in distillation sometimes they use an isopropanol water ice bath to slow the corrosion of metal parts and it gets very cold