Acid/bleach Standard Solution

[Mitchell]

Hello World. First post here, though I've been reading for a while. I'd like to thank lazersteve for creating excellent DVDs. If you're new to this refining process like I am, buy them. They'll save you time and materials and keep you safe; well worth the investment. Also, I'd like to thank patnor for putting out his ebooks on BGA and flatpack recovery. If you haven't looked into that, you need to. The numbers say there is just as much gold by weight (0.005%) in those chips as on gold fingers from ISA, RAM, PCI, etc. If memory serves, his yield was 7.1g from 1336g of material.

I'm very new to this, but I'd like to think I started in the right ways. I'm most of the way through Hoke's book. I've been reading on the forum for a while now. I bought most of my safety equipment before I started buying chemicals, and have only just processed my first batch of fingers using the AP method. 1kg of mixed fingers yielded almost exactly 5.0g. Which is about what I expected, based on Steve's DVD in which he processed 600g of fingers from ISA cards, which yielded 3g. Same ratio, and there's that 0.005% by weight I mentioned a minute ago.

Nitric scares me. Thank you Geo for your story and warning regarding its handling. I need to find a respirator suitable for use with nitric, and I was about to buy one until I saw somebody's signature that said something along the lines of "no cartridge filter respirator will filter nitric fumes!" There goes the 3M full mask from my ebay shopping cart. Any recommendations? Since I'm new to this and nitric scares me, I recently used the HCL/clorox method to dissolve 2 grains of gold for the standard solution which Hoke recommends in her book. I diluted the auric chloride (or chloroauric acid??) in a 30ml dropper bottle and it's nice and yellow like it should be, having seen Steve's DVD on how it should look. I made up a stannous solution exactly as per Hoke's recipe, acquired a small ceramic spot plate and set out to test my stannous against my gold solution. I just love these acquaintance tests, they help to keep things interesting between paychecks :lol: . At any rate, I did get an immediate and impressive color change reaction, but it wasn't purple like I was expecting. 1:1 gold to stannous, it was pretty much black, as expected. Diluting the gold solution with 10 drops of water, it was very dark brown. Diluted with 20 drops, it was a yellowish brown, though still quite dark. I calculated my standard solution to contain a gold concentration of 4.32g/L. That gives me a very good standard against which to test solutions of unknown value.

Anyway, why was my spot test brown and not purple? Was it because I dissolved the gold in HCL/clorox and not AR? I don't suppose the color matters much, so long as I'm able to detect change. I'm colorblind anyway! My fiance's grandfather was an analytical chemist for the FDA for a number of years and he's been a great resource of information for me. But he's not familiar with these processes and hasn't been able to offer much help after 20 years of retirement now. Any and all help and advice is appreciated!

Mitch

 

[joubjonn]

black is good! dark purple looks black right?

kinda splitting hair's with black vs dark purple. the depth of the color (darker vs lighter) for testing gold solution with stannous. where the less concentrated gold will develop lighter shade of purple. if that makes sense!

 

[goldsilverpro]

The numbers say there is just as much gold by weight (0.005%) in those chips as on gold fingers from ISA, RAM, PCI, etc. If memory serves, his yield was 7.1g from 1336g of material.

7.1/1336 = .0053. That is about 0.5%, not .005% - 005% is only about $1/pound. To convert a decimal to percent, multiply by 100.

I've had a lot of people working for me over the years and about the only ones I had to let go were those that were afraid of the chemicals or those that had shaky hands. They were an accident waiting to happen. Color blindness is not too great either, but those people can usually adapt.

 

[Mitchell]

7.1/1336 = .0053. That is about 0.5%, not .005% - 005% is only about $1/pound. To convert a decimal to percent, multiply by 100.

You're right, of course. I meant to say half of one percent of the total weight.

What do you provide your employees for a respirator? With the appropriate safety concerns, I would have less cause for trepidation.

 

[nickvc]

If you want the fumes away from you then you need a fume hood and if possible a scrubber, failing that do sealed reactions in conical beakers with the feed pipe running into water and from there to a lye, water and a little hydrogen peroxide, this will still need venting off but it does contain much of the more dangerous fumes, this set up was described by 4metals a little while ago.
Bad news but masks are a waste of time and money unless they are forced air ones.

 

[goldsilverpro]

7.1/1336 = .0053. That is about 0.5%, not .005% - 005% is only about $1/pound. To convert a decimal to percent, multiply by 100.

You're right, of course. I meant to say half of one percent of the total weight.

What do you provide your employees for a respirator? With the appropriate safety concerns, I would have less cause for trepidation.

A FUME HOOD!