Swim tried heating a mixture of NaCl, CaCl and aluminum sulfate (dried by heating) according to US patent 1818839, but found that the temperature was so high to melt it that he abandoned it.  Later, he tried heating some anhydrous zinc chloride in an evaporating dish on a hot plate and found that it could be melted fairly easily.  The next step is to try heating a mixture of zinc chloride and aluminum sulfate to make anhydrous aluminum chloride which sublimes at about 180 degrees C (http://www.aluminumchloride.net/) and can be distilled off.  A hybrid retort was constructed as shown in the picture.  The distilling flask has a copper bottom, rubber gasket and the rest of the apparatus is glass so the distillate can be seen.  If it condenses in the tubing, it could be heated to help it pass into the receiver (3 neck reaction flask) or can be scraped out of the tubing after cooling the apparatus.  Also see US patent 1541068.  One possible problem is the zinc chloride reacting with the copper.  As long as it doesn't corrode all the way through, it shouldn't be a problem.  Can the copper be coated with something to protect it?  How about high temperature paint?

Anhydrous zinc chloride is used in electroplating and aluminum sulfate is used for lowering the soil pH for acid loving plants like azaleas, etc.


Coating pennies using zinc chloride.
http://www.instructables.com/id/Turn-Copper-Pennies-into-Silver-and-Gold-Chemistr/

http://michaelsherlock.com/2008/08/07/how-to-make-a-gold-penny/