Used sand

Greetings to everyone,

I have a tray which I put used sand in to dry in order to reuse it later,

I have noticed a relatively large amount of a green precipitation, I am talking about the green of the copper salts one,

What could this kind of effect indicate?

Regards
 
Greetings to everyone,

I have a tray which I put used sand in to dry in order to reuse it later,

I have noticed a relatively large amount of a green precipitation, I am talking about the green of the copper salts one,

What could this kind of effect indicate?

Regards
what was the sand used for ?
 
Telling us the specific activity is much more useful. We don’t use sand in that practical, but have just used it for burning materials

Well it could be already there when I first started working in this school and maybe I can't remember it,

Judging by its colour it is copper carbonate, does anyone have any tips to help me prove this?
 
Well it could be already there when I first started working in this school and maybe I can't remember it,

Judging by its colour it is copper carbonate, does anyone have any tips to help me prove this?
I would try washing a small amount in acid, that should do well for most copper salts I think.
 
Well it could be already there when I first started working in this school and maybe I can't remember it,

Judging by its colour it is copper carbonate, does anyone have any tips to help me prove this?
add an acid and see if you get a blue solution ?
 
Yes, that looks like copper sulfate solution.

There was an ISA some years ago which had varying quantities of copper carbonate mixed with varying quantities of sand. When I started working here I found a great big bowl full of 100 ml beakers with the sand/copper carbonate mixtures in and arranged for them to be disposed of at the following chemical waste collection. I wonder whether one of your predecessors tried to separate out such a mixture using a fine sieve and therefore leaving a small amount of the copper carbonate in the sand.
 
Getting that out will take some effort. If you have a hotplate stirrer I would submerge the sand in dilute acid and have it kept hot ( not boiling) and stirring for as long as you can. May need to do that a few times

Although personally I would discard it and replace it with stuff you know is clean SciChem sell silver sand for about £5 for 5kg. maybe add some to your next order
 
Yes, that looks like copper sulfate solution.

There was an ISA some years ago which had varying quantities of copper carbonate mixed with varying quantities of sand. When I started working here I found a great big bowl full of 100 ml beakers with the sand/copper carbonate mixtures in and arranged for them to be disposed of at the following chemical waste collection. I wonder whether one of your predecessors tried to separate out such a mixture using a fine sieve and therefore leaving a small amount of the copper carbonate in the sand.
Yeah, it must be this
 
Getting that out will take some effort. If you have a hotplate stirrer I would submerge the sand in dilute acid and have it kept hot ( not boiling) and stirring for as long as you can. May need to do that a few times

Although personally I would discard it and replace it with stuff you know is clean SciChem sell silver sand for about £5 for 5kg. maybe add some to your next order
And after the stirring am I using normal filter paper to catch the sand?
 
Decant the copper sulfate solution, then filter the sand and wash with water?
Unfortunately you won't be able to use the copper sulfate because you won't know what concentration it is and it may still contain sulfuric acid as you won't know whether the copper carbonate or acid is in excess. You will then have the issue of how to dispose of this solution. It sounds like a lot of time and hassle to retrieve some sand when it is so cheap to buy new.
 
Unfortunately you won't be able to use the copper sulfate because you won't know what concentration it is and it may still contain sulfuric acid as you won't know whether the copper carbonate or acid is in excess. You will then have the issue of how to dispose of this solution. It sounds like a lot of time and hassle to retrieve some sand when it is so cheap to buy new.
React any excess acid with copper carbonate/oxide then filter off the excess solid and evaporate to get copper sulfate crystals.
 
I am not sure I have understood the way which I separate the sand from the acid,

Am I supposed to pour the sulphuric acid with the mixture to a beaker through a paper filter?
 
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