Some weeks ago I came across some black sand on my land. Under x100 magnification I could see a lot of black grains coated with, what appeared to be, gold. I magnetically separated this to about 70% magnetite and 30% tailings; the latter contained a lot of white grains (milky quartz?). I subjected 4 portions of the magnetite fraction to conc nitric acid, conc sulphuric acid and roasting with and w/o NaCl, with no apparent change - so not pyrites.
I then leached 1kg of the magnetite with HCl and Hypoclorite, adding the latter in small increments over 5 hours with stirring. I syphoned off and filtered 6 x 500ml beakers of golden orange liquid (chloroauric acid?). On diluting some I got a yellow liquid and putting some aside to evaporate I got yellow crystals (gold chloride?). I then split one beaker of liquid into 3 - 1 as control, to 1 I added 0.5M SMB and to 1 I added T-60, a proprietary precipitant (http://www.goldmineworld.com) and then raised the pH slowly with NaOH. At about pH 2.5 I got a large amount of brown precipitate from all 3. I filtered to get a reddish brown "mud" (gold hydroxide?). I boiled off a fraction of the original lixiviant to get a red-brown amorphous solid (gold oxide?). So far, (apparently) so good. Now is where everything starts to go "off the rails".
Gold oxide is supposed to be unstable to heating above 245C, so I heated to well above this temperature with no apparent change. Could I have platinum oxide?? To two 100ml portions of the original liquid I added saturated SMB and T-60, expecting to get a brown precipitate ie gold powder. What I got was some white cloudy precipite. I left overnight to settle and came back this morning to see a slight yellowish supernatent and cloudy white precipitate with the former and clear supernatent and a gelatinous precipitate (about 1/4 of the total) with the latter.
At this rate I'm going to be knee-deep in white snot without a single tiny flake of gold to show for my efforts.
What am I doing wrong?
I then leached 1kg of the magnetite with HCl and Hypoclorite, adding the latter in small increments over 5 hours with stirring. I syphoned off and filtered 6 x 500ml beakers of golden orange liquid (chloroauric acid?). On diluting some I got a yellow liquid and putting some aside to evaporate I got yellow crystals (gold chloride?). I then split one beaker of liquid into 3 - 1 as control, to 1 I added 0.5M SMB and to 1 I added T-60, a proprietary precipitant (http://www.goldmineworld.com) and then raised the pH slowly with NaOH. At about pH 2.5 I got a large amount of brown precipitate from all 3. I filtered to get a reddish brown "mud" (gold hydroxide?). I boiled off a fraction of the original lixiviant to get a red-brown amorphous solid (gold oxide?). So far, (apparently) so good. Now is where everything starts to go "off the rails".
Gold oxide is supposed to be unstable to heating above 245C, so I heated to well above this temperature with no apparent change. Could I have platinum oxide?? To two 100ml portions of the original liquid I added saturated SMB and T-60, expecting to get a brown precipitate ie gold powder. What I got was some white cloudy precipite. I left overnight to settle and came back this morning to see a slight yellowish supernatent and cloudy white precipitate with the former and clear supernatent and a gelatinous precipitate (about 1/4 of the total) with the latter.
At this rate I'm going to be knee-deep in white snot without a single tiny flake of gold to show for my efforts.
What am I doing wrong?
