question about cementing silver from nitric

[azdave35]

i have a nitric solution with silver,copper and lead dissolved in it...my question is when i use copper to cement the silver out...will only silver drop out or will it also drag some of the lead out with the silver ?...thanks in advance

 

[HAuCl4]

Only the silver should drop, but if you wish to decrease the lead contamination, you can add a little sulphuric acid and drop the lead cleanly first as sulphate. Then you filter it out very easily, and then proceed with the copper cementation. That way you can also recover the copper later using iron, without fear of lead contamination. 8) :shock: 8)

 

[Sucho]

Hi.

dropping silver with copper depends on standard electrochemical metal potential.In regard of this potential, metals are listed in electrochemical series.
in this series, metal with a lower potencial could drop out metal with higher potential- metal(copper) can drop out only metals on the right side of it.
lead relative to copper is left- copper could not drop out lead from solution

you can also use Search box.

Sorry for my English

 

[qst42know]

Only the silver should drop, but if you wish to decrease the lead contamination, you can add a little sulphuric acid and drop the lead cleanly first as sulphate. Then you filter it out very easily, and then proceed with the copper cementation. That way you can also recover the copper later using iron, without fear of lead contamination. 8) :shock: 8)

Keep the sulfuric out of the silver nitrate, you will also create silver sulfate.

 

[HAuCl4]

It's OK unless you put too much acid.

 

[azdave35]

what i am working with is silver / lead ore..is there any other way to drop or cement the lead out first before the silver ?...i would try the sulfuric acid but i dont want to sabotage getting the silver out...thanks in advance

 

[qst42know]

If you use copper to cement the silver, the lead stays in solution. You don't need sulfuric. Just wash the cement silver well to avoid any drag down.

 

[azdave35]

what do you mean by "wash the cement silver"?...thanks in advance

 

[qst42know]

Get it in a vacuum filter funnel and rinse well with hot water.

 

[azdave35]

so basically i cement all the silver out...then decant the solution off...the take the powder and wash it with hot water a few times in the vacum filter?...also if i wanted to drop the lead out after the silver is out what is the best way to do that?..thanks in advance

 

[qst42know]

To recover and melt? Probably best to use zinc.

To drop and dispose of properly as a solid hazmat you could use scrap iron.

How much lead are you dealing with?

 

[azdave35]

i would like to keep the lead..we use it in assay work

 

[qst42know]

If you are set up to do assays is there a reason you don't cupel the lead from the silver?

Lead for assays has to be a known purity. You may be better served to sell the recovered lead for scrap and purchase pure lead.

 

[azdave35]

i have tried to scorify and cupel but the scorification process doesnt get all the copper out....and when you try to cupel...the copper tends to drag some of the silver into the cupel

 

[qst42know]

It sounds like you need to adjust your assay flux and technique. One method is described starting on page 111.

http://books.google.com/books?id=oeoMAAAAYAAJ&printsec=frontcover&dq=fire+assay+fulton&source=bl&ots=g9y5-QGRCt&sig=Yv3Pey0lByIjlU11tmWOpiXHM_A&hl=en&ei=wwQ8TcekKMys8Aar1czjCg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBkQ6AEwAA#v=onepage&q&f=false

What I know of fire assaying comes from this book. The whole book deserves a read.

 

[azdave35]

we dont use flux in the assay..we do scorification assay's (lead fusion) ..the only drawback is if you have too much copper they dont work very well

 

[qst42know]

Your difficulties are discussed in the book. As well as a few possible solutions. Honestly I think it would be worth your while to read the whole book. It will be costly to part all your results in nitric.

http://books.google.com/books?id=oeoMAAAAYAAJ&ots=g9y5-QGRCt&dq=fire%20assay%20fulton&pg=PA97#v=onepage&q=scorification&f=false

 

[4metals]

What type of acid flux do you use along with the granulated lead in your scorification? If you have a flux cap more of the copper will go into the flux, possibly enough for the scorification to work better.

Qst42know is absolutely correct about recycling the lead. Any silver retained in your recycled lead will show up as values in your scorification assay. When multiplied to obtain your oz per ton from the assay it can be a huge error. Assay lead is very low in silver (usually under 1 ppm Ag)