Chemical Forums

Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: organoman on June 15, 2007, 03:28:47 AM

Title: Separating NaCN and NaCl
Post by: organoman on June 15, 2007, 03:28:47 AM

Hi all,
I have a mixture of about 25% NaCN and 75% NaCl in form of solid. I want to isolate NaCN in at least 95% purity in the lowest possible cost.
Solubility of NaCN in water is about 85% at 50 deg while that of NaCl is 35% only. So I have tried to use preferential solubility of NaCN in the amount of water that is just sufficient for it and separating the solids left behind considering as NaCl.But I don't have any success till now.
Can anybody suggest something better.
Thanks.

Title: Re: Separating NaCN and NaCl
Post by: AWK on June 15, 2007, 08:43:38 AM

http://www.nist.gov/srd/PDFfiles/jpcrd643.pdf

Title: Re: Separating NaCN and NaCl
Post by: hmx9123 on June 15, 2007, 11:50:00 AM

Personally, I'd boil the solution and filter it boiling.  Repeat a few times.  You'll have almost all NaCN at that point in solution.  Then cool down to ice temp and it will crash out.  This works because the solubility of NaCl at 100°C is about 37g/100mL H2O, and at ice temp it's about 35 - a flat solubility curve.  Do we need to remind you of the dangers of cyanide salts?