Induction Furnace Copper Melt

The copper slug on the left hand side was made up from thin copper wire balled and compressed before melting, the slug on the right came from copper waste sludge from my refining stock pot a swipe with nitric acid shows that there are some precious metals present.

The slug on the right will be remelted into an anode for parting in a cell.

My only regret is not buying the induction furnace sooner, no more propane bottle freezing or running out of fuel at a crucial moment.

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Slug on the right weighs 4.20 lbs, made from small diameter copper wire salvaged from fractional horse power electric motors.

A quick dip in a very dilute sulphuric acid would remove the oxides giving you a much cleaner looking slug, with copper sulphate as a by product. Any decent scrap yard that owns an XRF will gladly accept this as number one copper.

For those of you that sell copper bullion on ebay these copper slugs pack into a box really nice and compact. For every pair of slugs facing up another fits into the inverted space filling the gap.

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Last melt all my fine hair type copper has now been melted to what you see in the picture below.

Slug on the right weighs 5.50 Lbs., had I heated the mould before pouring I would have had a much nicer looking copper button. Also the black coating could be carbon from the oil I pre coat the mould with prior to pouring.

I'm using a large 35 lb slag mould to pour into.

A 6 lb copper melt in a 15 KVA furnace would be its upper limit and not a gram more.

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It doesn't seem like too many people use furnaces for separation of consolidating their scrap. I have been using waste oil burners and simple furnaces to take the ally off steel and it works well. I have also done copper and am looking to build a brick furnace so I can melt things like alternators and starters etc so I can get the copper out of those. Oil heat and power make it pretty easy and of course it's a free fuel that can be put to good use and people are happy to be disposed of in a responsible manner.
You can see some of my burner setups and melts here: https://www.youtube.com/user/glumpy10/videos

I see a lot of the doomsdayers save pennies for the copper, they would probably ship themselves if they saw all that copper in one place. Maybe you could get more for it selling it to the gloom and doomers than the scrap yard?

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Originally Posted by glumpy

It doesn't seem like too many people use furnaces for separation of consolidating their scrap. I have been using waste oil burners and simple furnaces to take the ally off steel and it works well. I have also done copper and am looking to build a brick furnace so I can melt things like alternators and starters etc so I can get the copper out of those. Oil heat and power make it pretty easy and of course it's a free fuel that can be put to good use and people are happy to be disposed of in a responsible manner.
You can see some of my burner setups and melts here: https://www.youtube.com/user/glumpy10/videos

I see a lot of the doomsdayers save pennies for the copper, they would probably ship themselves if they saw all that copper in one place. Maybe you could get more for it selling it to the gloom and doomers than the scrap yard?

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Sweating the aluminium from alternators you may find some of your copper is going into the aluminium melt.

Aluminium has a lower melting temperature, once molten acts as a solvent lowering the melt temperature of the copper.

To give some examples, lead foil is used in a fire assay, it's purpose is to lower the melt temperature of the surrounding metals allowing the metals being assayed to be collected into the melted lead leaving a bead of precious metals behind once the lead has been absorbed into the bone ash cupel.

Copper or silver have both been used in smelting as collectors of metals having a much higher melting temperature, again when copper or silver is in the molten state these metals have become solvents. Certain flux's also help to lower the melting temperature while other types of flux's added to the smelt charge will take up unwanted metals as oxides.