Geo
Well-known member
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?
precipitating with ferrous sulfate
- Thread starter Geo
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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
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
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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.
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.
kumbirai.mhere
Active member
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
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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
Well-known member
Testing with stannous chloride will tell.
kumbirai.mhere
Active member
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
Active member
It's light green in color and can be bought fresh from store in a sealed package
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You can fix that easily with a dash of HCl
Ravi Pal Singh
Member
please explain complete procedure how to add ferrous sulfate after I have denoxed the solution …
should I add ferrous to water then add to solution ?
Should I also add HCL to ferrous sulfate solution and then add to AR ?
Can I add the crystals of ferrous sulfate straight away ?
should I add ferrous sulfate to cold, warm, hot or boiling AR ?
What’s the correct way
should I add ferrous to water then add to solution ?
Should I also add HCL to ferrous sulfate solution and then add to AR ?
Can I add the crystals of ferrous sulfate straight away ?
should I add ferrous sulfate to cold, warm, hot or boiling AR ?
What’s the correct way
Depending on your source of ferrous sulfate it may be contaminated with other solids.
Ravi Pal Singh
Member
No what makes you think that ? I have good ferrous sulfate from a good supplier of lab chemicals … what I am asking is how to use it properly please read my above thread
Welcome.
Slowly now, patience and someone might chime in.
The reason for Eaglekeepers question is that Ferrous Sulfate go bad in time, and need refreshing from time to time.
If you search the forum the answer gas been asked and replied to many times.
This is why I mentioned it..... and that's why I said "depending on your source of ferrous sulfate"
You can either watch from the beginning or fast forward to 12:22.
Like and subscribe to his channel.
Hi.
Just dilute in water and add a little sulfuric acid or battery electrolyte.
pour a lot sulfate, don't be stingy.
Here is a video instruction:
Ravi Pal Singh
Member
Thanks for such a nice video … it explains a lot (but I don’t understand the language in the video
) but still it clears my doubtslanguage of inscriptions - russian...Thanks for such a nice video … it explains a lot (but I don’t understand the language in the video
you can use a translation program for screenshots, photos...
First, quench the nitric acid using urea, then add ferrous sulfate..
is advisable to wait 12-24 hours for the gold to completely precipitate from the solution...
in general, an old, time-tested method
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Copperas, Iron II sulfate, ferrous sulfate...degrades with time, temperature and humidity. It degrades into Iron III sulfate and Iron III oxide-hydroxide. Degradation is noted by a color change from pale green cristals to whiteish, yellowish, to brownish appearance. It should not be used. Get fresh greenish crystals. Prepare a solution by adding 50 grams of fresh Iron II sulfate in 100 ml distilled water for every 7.5 grams of expected gold. The solution will be pale green but cloudy. Heat gently, do not boil. Titrate the cloudy solution with hydochloric acid, drop by drop, until it clears. Filter the solution through a medium filter paper to remove anything insoluble such as free iron contaminants. It is now ready to use.
