Ferrous sulphate !! How it works exactly ??

xelexo
Advertise with us
Shop deals on ebay
shop deals on amazon
Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
G

Goldreallife

Member
Joined
Mar 8, 2021
Messages
10
Hello every one
I desolved gold in AR and I tested it with stannous and it gave me a positive black result , but when it try to drop it with ferrous It gives me black color with AR but after 24h I didn't got the gold down , I worked without heating in room temperature 25c• , I tested it with stannous again and there is a gold but it doesn't make any precipitation ... Please I nedd some details how ferrous works exactly because I can't get SMB in my location .
 
All we knows that FS is a good precipent of gold from AR , but im trying to work with it in my own solution but no result when I added it in my AR , I tested my solution with stannous and I got black positive result but after adding FS and after 24h I did not get the gold down !!
Please any important details like heating or concentration ... !
Thanks every one
 
You double posted.
With ferrous sulphate you need a lot more compared to SMB. (From what I've seen)
How much did you use on how much solution containing how much gold? Clean or dirty solution(base metals)?

Try a small sample and measure to see how much you need to get the gold to precipitate.

Martijn.
 
Have you read about the process and preformed the small acquainting experiments recommended by Ms Hoke yet?
The most common mistake by people who have watched YouTube and not studied is they forget to drive of the Nitric acid before trying to precipitate.
 
You more then likely used to much nitric in the first place so still have free nitric in your AR

if/when you still have free nitric in your AR - the gold will not drop (precipitate)

so you have to get rid of that free nitric before the gold will drop

There a number of different ways to get rid of that free nitric & I don't have time right now to post about all the different ways to do that

I am sure others will post something about that so its just a matter of someone else seeing your question & then posting some answers - answers will come - its a matter of waiting for people to see your question (the reason why you only need to post your question one time & not double post --- double posting will not get faster answers)

As I said - I don't have time right now - but will likely post an answer tomorrow

Kurt
 
kurtak said:
You more then likely used to much nitric in the first place so still have free nitric in your AR

if/when you still have free nitric in your AR - the gold will not drop (precipitate)

so you have to get rid of that free nitric before the gold will drop

There a number of different ways to get rid of that free nitric & I don't have time right now to post about all the different ways to do that

I am sure others will post something about that so its just a matter of someone else seeing your question & then posting some answers - answers will come - its a matter of waiting for people to see your question (the reason why you only need to post your question one time & not double post --- double posting will not get faster answers)

As I said - I don't have time right now - but will likely post an answer tomorrow

Kurt
Click to expand...
Sorry I duplicated posts because I'm new here , kurtak your answer was helpful but about nitric yes I eleminated it by urea , and I filtered it again , but the problem for me is about quantity and heating ... I need some details about that two factors !!
 
Urea doesn't actually eliminate excess nitric acid. While it has some effect on some of the NOx in solution, it doesn't eliminate excess NO3. A modern, and more effective, substitute is sulfamic acid. It is discussed at length here on the forum.

If you've already added urea and ferrous sulfate, and your stannous test still shows gold in solution, I'd recommend cementing the values out with copper. It will eliminate any excess nitric and only cement out precious metals, and perhaps mercury if it's present. Decant off the barren solution, redissolve the values with HCl and a minimum of nitric, then drop the gold again with your ferrous.

I should probably ask about your ferrous sulfate. Is it green or brown? How are you using it (dry or dissolved with an addition of some HCl)?

Pictures are always helpful.

Dave
 
It would help us to help you to if you told us everything you have done including what you refined and how much, if your test is truly black and not purple it may be you have no gold in solution.
 
FrugalRefiner said:
Urea doesn't actually eliminate excess nitric acid. While it has some effect on some of the NOx in solution, it doesn't eliminate excess NO3. A modern, and more effective, substitute is sulfamic acid. It is discussed at length here on the forum.

If you've already added urea and ferrous sulfate, and your stannous test still shows gold in solution, I'd recommend cementing the values out with copper. It will eliminate any excess nitric and only cement out precious metals, and perhaps mercury if it's present. Decant off the barren solution, redissolve the values with HCl and a minimum of nitric, then drop the gold again with your ferrous.

I should probably ask about your ferrous sulfate. Is it green or brown? How are you using it (dry or dissolved with an addition of some HCl)?

Pictures are always helpful.

Dave
Click to expand...
You gave such a great info , how can I know the quantity of sulfamic acid need to eliminate the nitric in the solution ?
about ferrous it's a green lequid very clean home made , I desolved pure iron in sulfamin acid and got it , how can I confirm that I don't have any nitric in my solution is there any test ?
should I have HCL to my home made FS for best result ?
 
nickvc said:
It would help us to help you to if you told us everything you have done including what you refined and how much, if your test is truly black and not purple it may be you have no gold in solution.
Click to expand...
Hello nickvc , the result of the test is very dark brown or if i can say very dark purple maybe yes , i m trying to upload a pic , I'm new in the forum I'll do my best to learn how upload a pic
and I will update my next expirements about Ferrous for the general knowleg here .
Thanks every one
 
That does not look like a positive test for gold unless the colors are way off. A positive test is clearly purple. If it turns black you should dilute the test solution so you can see the proper color.

Göran
 
Hello, masters, I have the same problem. I couldn't find an article on the forum explaining the exact process of precipitation with iron sulfate. Would you mind writing down the full process

Details such as heat, endearment, fs amount, reactions in liquid and color changes in precipitation with demlr sulfate, if all other conditions are suitable
 
I make my own FeSO4 by dissolving rusty nails in dilute sulfuric acid. If I'm in a hurry, I will use steel wool. 30ml of concentrated sulfuric acid and a few ounces of steel will make a good 500ml of saturated solution. I filter the solution after the reaction stops and the solution is completely cool. Regular filtration will work as the contamination is normally large enough particle size to use coffee filters. The solution should be a light aquamarine color. FeSO4 will not drive off excess NO2 like SMB will. The excess nitric acid has to be removed before the precipitation will work. As stated, sulfamic acid is best to use. Heat the solution until it is steaming. Add the sulfamic acid in small increments starting out as the reaction can be very vigorous. There is a real chance of a boil over. After the initial additions, you can add larger amounts. Don't assume that because the reaction stops that the nitric acid is depleted. Cover the solution and turn the heat up. When ALL action has stopped, add a few crystals of sulfamic acid. If there is a reaction, begin the additions as before. Repeat as necessary. Remove from heat and filter when cool. Add the FeSO4 in increments. Unlike SMB, you can test with stannous chloride as you go. Add FeSO4 and test. Repeat until the test is negative.
 
Geo said:
I make my own FeSO4 by dissolving rusty nails in dilute sulfuric acid. If I'm in a hurry, I will use steel wool. 30ml of concentrated sulfuric acid and a few ounces of steel will make a good 500ml of saturated solution. I filter the solution after the reaction stops and the solution is completely cool. Regular filtration will work as the contamination is normally large enough particle size to use coffee filters. The solution should be a light aquamarine color. FeSO4 will not drive off excess NO2 like SMB will. The excess nitric acid has to be removed before the precipitation will work. As stated, sulfamic acid is best to use. Heat the solution until it is steaming. Add the sulfamic acid in small increments starting out as the reaction can be very vigorous. There is a real chance of a boil over. After the initial additions, you can add larger amounts. Don't assume that because the reaction stops that the nitric acid is depleted. Cover the solution and turn the heat up. When ALL action has stopped, add a few crystals of sulfamic acid. If there is a reaction, begin the additions as before. Repeat as necessary. Remove from heat and filter when cool. Add the FeSO4 in increments. Unlike SMB, you can test with stannous chloride as you go. Add FeSO4 and test. Repeat until the test is negative.
Click to expand...
Do you have to crystallise the ferrous sulphate or you use it the filtered solution
 
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.
 
Thomas M Joseph said:
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.
Click to expand...
That's a wonderful way to do it Thomas, but it's equally as viable to just put the crystals in the solution and stir well. It's also a lot less hassle to do so. If you put too much in, it doesn't hurt.
 

Latest posts

Back
Top