precipitating with ferrous sulfate

[Geo]

I have been trying to do some remedial chemistry and have come to something I can't find the answer to. Is the reaction of ferrous sulfate on gold chloride a deprotonation process?

 

[butcher]

Copperas will effectively deNOx a solution, and precipitate gold.

DeNOx aqua regia

3FeSO4 + 2HCl + 2HNO3 --> Fe2(SO4)3 + FeCl2 + 2NO2 + 2H2O

FeSO4 + 3H2SO4 + 2HNO3 --> 3Fe(SO4)3 + 2NO + 4H2O

displace silver from nitrate
3AgNO3 + 3FeSO4 --> Fe(NO3)3 + Fe(SO4)3 + 3 Ag
(copperas not as sffective to ppt Pd fron nitrate solutions)


HAuCl4 + 3FeSO4 --> Au + Fe2(SO4)3 + FeCl3 + HCl

AuCl3 + 6FeSO4 --> 2Au + 2Fe2(SO4)3 + 2FeCl3

http://www.docbrown.info/page07/transition06Fe.htm

 

[anachronism]

A word of caution though.

Adding Ferrous Sulphate to a solution that still contains Nitric precipitates some gold them goes off like a rocket in a cyclic reaction. A "boil over" type reaction is very common place so have a catch pan.

 

[Lino1406]

Not deprotonation. Redox reaction

 

[kumbirai.mhere]

Copperas will effectively deNOx a solution, and precipitate gold.

DeNOx aqua regia

3FeSO4 + 2HCl + 2HNO3 --> Fe2(SO4)3 + FeCl2 + 2NO2 + 2H2O

FeSO4 + 3H2SO4 + 2HNO3 --> 3Fe(SO4)3 + 2NO + 4H2O

displace silver from nitrate
3AgNO3 + 3FeSO4 --> Fe(NO3)3 + Fe(SO4)3 + 3 Ag
(copperas not as sffective to ppt Pd fron nitrate solutions)


HAuCl4 + 3FeSO4 --> Au + Fe2(SO4)3 + FeCl3 + HCl

AuCl3 + 6FeSO4 --> 2Au + 2Fe2(SO4)3 + 2FeCl3

http://www.docbrown.info/page07/transition06Fe.htm

Wow so I can forget about sulphamic acid or even urea and add ferrous sulphate bit by bit. What's the color change for completion of precipitation when using ferrous sulphate

 

[Spaceships]

Wow so I can forget about sulphamic acid or even urea and add ferrous sulphate bit by bit. What's the color change for completion of precipitation when using ferrous sulphate

The solution develops a yellow tinge due to the iron. You'll need to test with stannous to ensure it's all dropped. Edit- no don't stop using Sulphamic. It's a strong reaction when it has to denoxx so use each chemical in order as you would before.

 

[Martijn]

Wow so I can forget about sulphamic acid or even urea and add ferrous sulphate bit by bit. What's the color change for completion of precipitation when using ferrous sulphate

Testing with stannous chloride will tell.

 

[kumbirai.mhere]

The solution develops a yellow tinge due to the iron. You'll need to test with stannous to ensure it's all dropped. Edit- no don't stop using Sulphamic. It's a strong reaction when it has to denoxx so use each chemical in order as you would before.

Sulphamic acid is hard to get in Zimbabwe but there's plenty of ferrous sulphate

 

[Yggdrasil]

Sulphamic acid is hard to get in Zimbabwe but there's plenty of ferrous sulphate

Yes but is it pure and not oxidized?
It has to be fresh and un-oxidized to work.

 

[kumbirai.mhere]

Yes but is it pure and not oxidized?
It has to be fresh and un-oxidized to work.

It's light green in color and can be bought fresh from store in a sealed package

 

[Spaceships]

Yes but is it pure and not oxidized?
It has to be fresh and un-oxidized to work.

You can fix that easily with a dash of HCl