Non-Chemical Rotary Furnace - Anyone seen a small one? Pictures? Etc.

[4metals]

These photo's of the schematics for a rotary furnace may help. I used the smallest one made for years to smelt jewelers sweeps with copper. They called it small but it was 4 feet in diameter and about 5 feet tall when upright and standing in it to reline it with new refractory.





That size could melt 2 drums (55 gallon) full of prepared sweeps plus flux.

 

[snoman701]

These photo's of the schematics for a rotary furnace may help. I used the smallest one made for years to smelt jewelers sweeps with copper.

How much copper did you add? Probably enough to make most efficient anode based on fire assay.

Was the copper in powder form milled with the flux & sweeps, or just scrap copper?

 

[4metals]

Since jewelers sweeps essentially contain karat gold the rule of thumb was keeping the anodes at 1% precious metal so the anodes were close to 98% copper. The copper was added as shot made from the copper cell cathodes.

We ran 2 drums of sweeps a day, blended with flux it was 4 drums and about 900 pounds of copper. The anodes in the copper cell performed well and eventually we halved the copper with no ill effects. 4 days of melting sweeps followed by slag Friday's. Slags were always remelted and always yielded 2-300 ounces of copper based collector metal for running in the cell. Considering we processed an average of 800 ounces of gold from sweeps a week the slag hang up was about 1/3 of 1% of the gold refined.

The sweeps were mixed with flux components in a double cone blender and compressed into plugs with the equivalent of a gigantic pelletizer. Then about every 20 minutes, the flame was shut, the back door opened, and a plug was tossed in. After 5 minutes the flame went back on but the rotation never stopped. This minimized the burner blowing valuable dust out the front pour spout. The full charge of copper was added with the first few plugs and when it was molten, the routine of plug every 20 minutes was started.

Metal accountability was always 99.7 or better after smelting, slag melting, and slimes processing but the anodes were assayed before going into the cell room so we knew what was going into the cells. Once the whole system was up and running we could produce about 800 ounces of fine gold a week. That was back in the day when jewelry was actually mass produced in the US!

 

[snoman701]

Awesome post! Thanks 4metals!



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