This is considered a bronze alloy and I don't have an answer for you but I do know where two spots where you may be able to get a proper answer.
The first is the Copper Development Association Inc. at www.copper.org/
Go to "Resources" / "Questions?". Fill out the form and state your question there.
The second is EBNER Industrieofenbau (Austrian) at www.ebnerfurnaces.com/
Please let us know how you make out.
Peter J. Stewart-Hay
Stewart-Hay Associates www.Stewart-Hay.com
519 641- 3212