how to cheak the silver

[rajkumarkp]

i have a silver refinery shop in india, i desolve the 1000gms of silver(750 grms silver,250grms copper) in nitricacid then i put copper bar in that solution it came like cement type,here is my question how to cheak there is no silver in that solution?,and how to recover the copper?, we put some iron to recover the copper but it comes like green colour.any chemicals to recover that copper?

 

[butcher]

HCl or table salt will check for silver if silver it will precipitate as white powder if much in solution, if very little in solution will change solution to milky color.

Iron will replace copper from solution, but you may have a neutral solution try adding a small amount of acid and see if that helps, electricity would also work here to drive reaction.

 

[4metals]

Check the silver, as Butcher said, but don't add the salt to the solution, instead add a few grains of salt to tap water, just enough so there is some chloride in the water. Then use a glass stirring rod to take a drop of the solution you are cementing out and place it in the water. If there is any silver remaining in solution the drop will turn a cloudy white from the formation of silver chloride. If the cementing takes too long try and bubbling air into the tank you are cementing in to mix up the solution.

The copper drops better at a pH of 1.5, raise the pH and then add the iron. The copper should drop as a reddish metal sponge. Not pure but a good candidate for electrolytic copper refining.

 

[Frankk12]

i desolve the 1000gms of silver(750 grms silver,250grms copper) in nitricacid then i put copper bar in that solution it came like cement type, put some iron to recover the copper but it comes like green colour.any chemicals to recover that copper?

Here the silver is precipitated with copper
The copper precipitated with iron

1) Can this left over solution be reused
2) If not can it be discarded
3) If not how can it be neutrilezed

 

[Frankk12]

If I am not wrong dealing with waste posted by 4metals will take care of this problem.

 

[lazersteve]

Copper nitrate (the blue solution left over from cementing silver from silver nitrate with copper) is a useful by product.


I have posted several ways to utilize it.


Steve

 

[Frankk12]

Hi Steve
I found that thread
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=5410&sid=f5d04aa055a417e552b48ec0be6d6ff2#p46252

The left over copper oxide can then be converted to copper metal in the presence of hydrogen or carbon monoxide:

How would you do this

 

[lazersteve]

Heat the copper oxide in graphite crucible with a reducing flame

Steve