Reducing Tin and Lead impurities on copper scrap

Hi forum member,

Our company is copper rod and wire manufacturing. We produce copper rod from Copper Cathode (Electrolytic Tough Pitch grade) with Shaft Furnace process followed by hot rolling. We always check the impurities (metal impurities, Oxygen content) every time we got copper cathode from our vendor. To make sure that material specification is OK.
Sometimes we use copper scrap with percentage less than 10% (along with Copper cathode) as a raw material. We make a limitation for copper scrap composition due to higher impurities content on it (compare to copper cathode). If we put higher copper scrap percentage, product quality getting worse due to impurities.

We make a grading for copper scrap according to impurities content, especially for metal impurities such as : Sn, Pb, Te,Fe. Higher impurities content means lower grade. And lower acceptable percentage in raw material composition.

I would like ask forum, is there any experiences about applied technology to reduce impurities on copper scrap? (especially to reduce Sn and Pb impurities). If you have, please share me the information or may be you can give me contact person/number that I contact for further discussion.

I found patented technology related to this matter in US Patent website,
(REMOVAL OF TIN FROM COPPER SCRAP, US Patent No: 3,615,357)
May be forum member has information about commercial application of this patent. Please share the information, thanks a lot.

Hello Siampudan,

Take a look at this patent on Google Scholar:

Separation of contaminant material from copper wire and cable
United States Patent 4284428 Filed 10/29/1980
Assignee: Western Electric Co., Inc. (New York, NY) Keep in mind however that it is my personal experience that Western Electric, in the rush to patent, sometimes patents things that really do not work that well.

"Copper scrap from chopped and separated copper wire and cable is treated to remove contaminants still remaining on or mixed with the copper by sequential treatment, first in a sodium nitrate-potassium nitrate fused salt bath followed by a cuprous chloride fused salt bath."

Experimentation would be fairly simple.

Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641- 3212

depending on the scraps quality you can make pyro refining on the alloy; getting very good quality scrap to add to your cathodes.