Sciencemadness Discussion Board

Downs cell + MgCl2

pesco - 19-11-2015 at 03:35

Hi,
I am setting up Downs cell and got a question related to electrolyte.
In industrial process mix of NaCl and CaCl2 is used, however my CaCl2 is heavily contaminated with Mg. Think of Dolomite ... :D

Does anyone have any experience/knowledge if MgCl2 would interfere with cell operation ?

I've googled around heavily and haven't found the answer.

Regards

IrC - 20-11-2015 at 17:01

I would think since the reduction potential of Mg is lower than that of sodium then you have a problem. I could be wrong but I think your answer is that simple, and I'm guessing the lower than Na it is the bigger the problem. Not being a chemistry guru myself, perhaps Woelen or another member can give a better opinion.

Na+(aq) + e– Na(s) -2.714
Ca2+(aq) + 2 e– Ca(s) -2.87 higher
Mg2+(aq) + 2 e– Mg(s) -2.37 lower

pesco - 22-11-2015 at 07:46

Good point, thx.

I guess I better drop the MG(OH)2 with Ca(OH)2 or buy some clean CaCl2