How to dispose of expired copper sulphate

A. Hi Marisol Rosel,

I don't know if you have the copper sulphate [on eBay or Amazon]as a salt or as a solution.

If you have it as salt, I think it's quite easy, there's from chemical point of view no reason why it should expire, maybe for auditing purposes you should sample the batch, extensively test on the important parameters and requalify it as "good". The only thing is that, if it's still in the original package it could have additional moisture in it.
If that's no option, I'm sure you will find an interested third party who will buy (or take it for free) from you, even if it's "expired". Look for electroplating shops in your area, they may want to have it. I don't recommend to contact the agriculture companies, as the origin of the copper sulphate and storage conditions are unknown to me.

If it's liquid, you can only go for electroplating the Cu out, until you have low Cu in the liquid (< 200 mg/l.) then for the remaining part use selective ion exchange to remove the Cu and finally neutralise the remaining liquid and you can dispose it of.

Sounds easy, but means a lot of work and experience and if you're not already having the right equipment and people in house, better leave it. In that case you better try to find an outside company who wants to do this job for you, but be prepared for tough negotiations (the Cu value is already considerable so don't let them pull you a leg) and in Western Europe we can -fortunately- only use registered companies with a proven good track record and an allowance for that specific activity.

Best regards,

Harry.

A. Marisol,

copper sulphate does not go bad, or expire in the sense that it is no longer useful. You should try to sell it to any of a number of companies, including companies that make agricultural chemicals, electroplating chemicals, or even animal food supplements.

Good luck!