Prompted by Göran to do the 'acquaintance tests' i thought it best to do a bit of maths first, instead of leaping straight in and botching it again.
Hoke's recipe in chapter IX, page 93 translates to :-
1.56g tin chloride crystals
23 ml water
2 ml HCl (30 drops were measured to find out)
SnCl2, Tin(II)chloride normally comes as the dihydrate (SnCl2.2H2O) giving 1.31g of actual SnCl2 in 23ml water + 2ml HCl.
That works out at 0.28[M], or 53,000 ppm concentration.
Lazersteve's recipe :-
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=5271#p45030
2g tin Powder
30ml HCl
This works out as 0.56[M], or 106,000 ppm concentration, about 2x the strength of Hoke's.
His photos show how excellent the colours come out.
Hoke's 'Two Grains in 2 oz Standard Gold Solution' recipe on the same page translates from grains/oz to :-
0.13g gold
57ml acids/water
= 0.012[M] , or 2400 ppm concentration of chloroauric acid.
Making that from clippings off a 1g .999 ingot took about 2 hours before all the 0.13g of gold had dissolved (no heating).
Using the Stannous Chloride i made earlier, 2ml of the solution was put in a plastic cup and diluted first with 2ml distilled water then 4,8,16,32 and so on, in order to halve the concentration each time.
Each concentration of solution was tested with the SC.
Even the use of the SC test needs some practice, as i got different results depending on which solution the test paper was dipped in, then had a drop of the other applied, or if both were applied as drops.
Also the amount of solution seems important - too much and not much happens.
So, here are the results at 2400ppm, 1200, ppm etc down to 37ppm gold concentration :-
The 75ppm photo doesn't show much, but a hint of brown was seen with the naked eye.
The most Amazing part is that the SC test easily shows up 150 parts-per-million, which would be a mere 0.09g of gold in 1 litre of solution !
This SC test shows Negative to a concentration below about 70 ppm, so it cannot be used as a 'there is No gold' kind of test, meaning that those very dilute values need be accounted for, if not eventually rescued.
Now, i cannot trust that i've made the stannous chloride solution correctly, nor that i'm using it right by putting it on cheap filter paper, mostly because the colours are not clear.
Chances are that something went wrong when i made the SC solution, so some tin(II)chloride crystals have been ordered so that a testing solution can be made as per the book.
P.S. i think i got the maths right, and checked them twice. There could still be errors though.
Edit: hopefully edited some errors without multi-posting
Hoke's recipe in chapter IX, page 93 translates to :-
1.56g tin chloride crystals
23 ml water
2 ml HCl (30 drops were measured to find out)
SnCl2, Tin(II)chloride normally comes as the dihydrate (SnCl2.2H2O) giving 1.31g of actual SnCl2 in 23ml water + 2ml HCl.
That works out at 0.28[M], or 53,000 ppm concentration.
Lazersteve's recipe :-
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=5271#p45030
2g tin Powder
30ml HCl
This works out as 0.56[M], or 106,000 ppm concentration, about 2x the strength of Hoke's.
His photos show how excellent the colours come out.
Hoke's 'Two Grains in 2 oz Standard Gold Solution' recipe on the same page translates from grains/oz to :-
0.13g gold
57ml acids/water
= 0.012[M] , or 2400 ppm concentration of chloroauric acid.
Making that from clippings off a 1g .999 ingot took about 2 hours before all the 0.13g of gold had dissolved (no heating).
Using the Stannous Chloride i made earlier, 2ml of the solution was put in a plastic cup and diluted first with 2ml distilled water then 4,8,16,32 and so on, in order to halve the concentration each time.
Each concentration of solution was tested with the SC.
Even the use of the SC test needs some practice, as i got different results depending on which solution the test paper was dipped in, then had a drop of the other applied, or if both were applied as drops.
Also the amount of solution seems important - too much and not much happens.
So, here are the results at 2400ppm, 1200, ppm etc down to 37ppm gold concentration :-
The 75ppm photo doesn't show much, but a hint of brown was seen with the naked eye.
The most Amazing part is that the SC test easily shows up 150 parts-per-million, which would be a mere 0.09g of gold in 1 litre of solution !
This SC test shows Negative to a concentration below about 70 ppm, so it cannot be used as a 'there is No gold' kind of test, meaning that those very dilute values need be accounted for, if not eventually rescued.
Now, i cannot trust that i've made the stannous chloride solution correctly, nor that i'm using it right by putting it on cheap filter paper, mostly because the colours are not clear.
Chances are that something went wrong when i made the SC solution, so some tin(II)chloride crystals have been ordered so that a testing solution can be made as per the book.
P.S. i think i got the maths right, and checked them twice. There could still be errors though.
Edit: hopefully edited some errors without multi-posting