boiling poor man's ar down

[steeranoff]

I've stepped my cat processing up and now I'm working out of an igloo
ice chest. The batches are taking about 7 gallons of poor man's ar,
which takes alot of soda ash and zinc, if I boil the ar down some wouldn't
it take less soda ash and zinc to work the acid? I am concerned about
losing values in a boil down stage.
thanks,
steve

 

[lazersteve]

Boiling down poor man's AR will result in salt formations. You can conserve soda ash and zinc by using the solution until it's dissolving power is used up.

Ultimately the amount of zinc required will depend on the mass of metals that you are displacing from the solution. The more dissolved metals the more zinc needed. If you use up all the available acid in the reaction stage your zinc will be spent precipitating the PGMs as opposed to converting acid into hydrogen.

The soda ash assists in neutralizing the excess acid that would otherwise consume your zinc. If you get your acid levels right you won't need much soda ash, if any at all. A little free acid is required to get the zinc into solution.

Steve

 

[steeranoff]

thanks.
steve