Salts coming out of solution at low temperature

http://www.formatebrines.com/tabid/237/Default.aspx

This, or the company (Cabot Specialty Fluids Ltd), might have good info.

Won't the solutions be frozen at -5 C and -10 C?

Dangerous Bill

It depends on the brine characteristics. For instance, eutectic NaCl brine remains liquid down to -6°F ≈ -21.1°C.

Yes, but a 2% solution?

DB

That could well be right. I'm not familiar with cesium formate brines, but that low a % probably would not furnish much protection against freezing, or even precipitation of the salt. Good point and GA. Welcome to CR4, btw!

Thanks for your comments guys, I am wondering what the concentration would be like at just above the freezing point. Where the liquid would be thicker but still liquid, and that portion of liquid that is flowing would be more concentrated. I am wondering if the water freezes first at 0 deg C and some of the salt is expelled from the solution making the unfrozen portion of solution stronger in concentration.

Thanks for your comments guys, I am wondering what the concentration would be like at just above the freezing point. Where the liquid would be thicker but still liquid, and that portion of liquid that is flowing would be more concentrated. I am wondering if the water freezes first at 0 deg C and some of the salt is expelled from the solution making the unfrozen portion of solution stronger in concentration.

Hi staggersandfalls,

Temperature does not change the physical composition of solutions. It changes ONLY if solute falls out of solution. Since you are working with a 2% solution, well below the solubility limit at 0ºC, I doubt that you would see anything fall out, even at -5ºC. (but you might be frozen at that point anyway).

Below are the solubility limits for cesium formate at various temps. (WIKI Solubility Tables)

Temp Sol. (g/100g H2O)

0°C 335

10°C 381

20°C 450

30°C 694

At 2%, you have 2 grams CsHCO2 in 100g of solution; the most you can have in solution at 0ºC is 335g CsHCO2 in 435g of solution. That's 77%.

Since you have a solution, the freezing point would be somewhat depressed. As said previously, probably not much. At the point where you have 2 phases; liquid and solid; it is conceivable that the phases could have different concentrations of the salt.

Mike