detecting copper in a waste stream.

[dlruss]

We are a scrap metal recyclers and we are looking for a way to detect copper in our waste stream. After shredding automobiles and "white goods" (refrigerators, washers, dryers) there is a considerable amount of copper wire that is not removed from the fuzz which will have foam rubber, rubber from tires, hoses, basically anything that is not metallic. We do remove Aluminum with an eddy current but the copper is unaffected and falls in the stream to the land fill. Any ideas?

[wpenrose]

The EPA has useful methods available online, but it generally takes some concerted searching to find them.

Your application calls for some form of electrochemical analysis. Many vendors have industrial grade, continuous analysis systems. They are expensive and require frequent maintenance. Look them up in a laboratory equipment guide.

Atomic absorption or emission spectroscopy such as ICP is also useful, but is even more expensive, especially if adapted to continuous sampling.

There are ion electrodes which supposedly will measure copper directly, but they require considerable sample preparation and there are many interferences, giving false positives or false negatives.

There are also some inexpensive chemical color tests, but they tend to be complex, take time, and require some skill with lab equipment. Look at American Public Health Association "Standard Methods for Water and Wastewater". This book is Expensive! Check the used copies in Amazon.com

There are test strips for copper, but even they are not simple to use. They're sensitive only to 10 parts per million, so you might have to evaporate a sample to a small volume on a hot plate. Afterward, you have to reduce the copper to the copper(I) state before using the test strips.
http://www.galladechem.com/catalog/e...-pk-of-100.htm

Dangerous Bill
Custom Sensor Solutions, Inc.
http://www.customsensorsolutions.com/

[djohnson]

Do you wish to detect or filter? We have a filtration system in development, relativley low cost, that removes heavy metals, copper and lead in particular. I can send you details if you wish - it will be available Q3. On the detect side you have a lot of chemistry to mess with, but I assume your effluent is within release guidelines - the point being that the various detection technologies will behave differently with ph for example. You may have to detect with two sensors.

good luck.

doug johnson
cambria corp
seattle