muriate of potash again

J.E. Shields
Sat, 30 Mar 2013 11:41:51 PDT
This all makes sense, Jim.  A century ago, and longer, the existing 
manufacturing processes did not produce the high purity we can attain today 
in chemical compounds.  Potassium and sodium are both present in all living 
things (and in their ash residues).  Sodium is also present in most natural 
deposits of potassium.  Sodium and potassium are hard but not impossible to 
separate by crystallization.  The sodium salt (chloride, sulfate, whatever) 
crystallizes out first and the potassium remains in the mother liquors 
(that really is a technical term) along with some left-over 
sodium.  Concentrate the liquids and repeat the process.  Eventually the 
potassium starts to crystallize out too.

You and I, like most other living things, need sodium as well as 
potassium.  I still would not want to buy fertilizers that I knew contained 
sodium and chloride.

Jim Shields

At 11:16 AM 3/30/2013 -0700, Jim McK. wrote:
>The discussion we had earlier this week about the identity of muriate of 
>potash seemed to provide a simple solution: that muriate of potash was the 
>same thing as potassium chloride.
>Now I've read something which makes me wonder. One source (the T H Everett 
>Encyclopedia of Gardening from the 1960s) makes the claim that muriate of 
>potash is 85% potassium chloride and 15% sodium chloride.
>That was written a half century ago. Can any of our chemists comment on 
>whether that might have been true back then but is/is not true now?
>It seems to me that if muriate of potash contains 15% sodium chloride, 
>then it's not the same thing as potassium chloride - certainly not the 
>same thing as Jim Shields' $100/oz potassium chloride.
>Table salt might be good for some plants (I've read that it's good for 
>asparagus), but many plants are sensitive to it - and who wants to pay 
>muriate of potash prices for table salt?
>Jim McKenney

Jim Shields             USDA Zone 5
P.O. Box 92              WWW:
Westfield, Indiana 46074, USA
Lat. 40° 02.8' N, Long. 086° 06.6' W

More information about the pbs mailing list