First post here - hello to the forum!
I got interested in refining gold for several reasons. I've been a metal detector enthusiast for about 35 years and have accumulated a nice little cigar box of gold & gold plated jewelry, not to mention two gold dental bridges (not sure how one could lose something like that). I also work in the commercial electronic aircraft industry, and after seeing hundreds of pounds of old computer boards (from mainframes) being thrown in giant 4'x4' boxes and sent off to the recycler I decided to start to pick off the larger sections of gold plated connectors.
So I began researching online and thought that I would start with YouTube videos since they were always the first hits that came up. I also looked at tons of amateur instructional websites.
I went ahead and purchased a small kiln & two propane torches, beakers, glass rods, urea, fluxes, pure tin, sodium metabisulfite, Muratic acid & Hydrogen Peroxide, and I ordered a 2l bottle of regents grade 70% nitric acid. I have gloves, goggles and masks. I also have several paper filters and strainers, including a 5 quart colander bowl that I can but giant 3gal coffee filters in. Add all this to tongs, testers, scales, etc. Yea, I went kind of nuts with the credit card.
My work area is outside. I live on 5 acres surrounded at least 40 acres of woods. The nearest neighbor is well over 500' away with lots of trees in between. I keep at least 30' from the house and have a 32" commercial fan blowing across the area where I'm cooking. The area I work in is a clearing of an acre where my house sits. No
Now that I'm all invested I realize that almost everything I learned on YouTube is wrong, at least when it comes to safety. Man am I glad I found this forum.
I watched people working with nitric acid fumes in garages right next to their cars, even one where the person holding the camera was coughing and complaining about the fumes or the guy was hacking while pouring in the acid. I saw people refining in the basement, pouring acid into hot water, wearing paper painting masks or swearing that a P100 filter was more than enough. I even saw one where the guy had a mask hooked to an air compressor. No filter, not a breathing compressor, just a rusty old Craftsman garage style compressor. I now wonder how many people are dead because of this.
I figure I'm only going to be a casual refiner. Currently I have around 6 ounces of various karats of solid gold scrap (dental and jewelry) that I would like to eventually purify, plus several handfuls of plated jewelry that has no value other than scrap. Once retirement kicks in I'll probably only be refining gold from metal detecting jewelry and panning. I have pounds of plated silver - not sure if I want to tackle stripping that though, at least not at this point.
I've been experimenting with small batches outside. The other day I wanted to see how nitric acid would work on gold plated electronic pins that HCl and H2O2 would not lift the gold from. I used a 1000ml beaker with 200ml HNO3 which covered the 1/2 of pins in the bottom. This was placed on a warming plate (always outside). At one point I was about 15' away and I smelled chlorine for a few seconds. Not real strong nor did it irritate - I would compare it to not much more than when you go to a public pool when they just treated it. I'll be neutralizing this with urea today to see what my results are.
Question: if I get a whiff of chlorine even though I'm a good distance from the HNO3 is this something to be greatly concerned about? There was just a few seconds of the smell but it still raised a red flag for me.
Question 2: This is really a noob question and doesn't fall under the safety category but with things like the gold plated pins or plated jewelry why can't one just use aqua regia to dissolve the gold? I can see where other metals can cause headaches but once I recover what turns out to be 80-90% purity why can't I smelt it with flux and then re-refine it? I bring this up with pins because I saved a coffee can of gold pins (new) from the garbage and I use them for my experiments with various ratios of acid compounds. For the most part nothing seems to fully lift the gold - at least when HCl is involved.
I'm still unsure if I'll build a fume hood as I'll likely only be refining once or twice a year max - enough to produce a few grams of pure gold. I also learned on this board that no free standing mask will offer full protection from nitric acid fumes. You folks seem to be the only ones who knew enough to prove this.
As for the YouTube videos... most of them are so casual with the fumes which is really a concern. At least they all wore gloves, though a lot of them just used disposal latex ones - something I found were pretty useless if you were handling electronic scrap.
Yesterday I downloaded the Hoke manual. I was up to 3am reading it last night.
I got interested in refining gold for several reasons. I've been a metal detector enthusiast for about 35 years and have accumulated a nice little cigar box of gold & gold plated jewelry, not to mention two gold dental bridges (not sure how one could lose something like that). I also work in the commercial electronic aircraft industry, and after seeing hundreds of pounds of old computer boards (from mainframes) being thrown in giant 4'x4' boxes and sent off to the recycler I decided to start to pick off the larger sections of gold plated connectors.
So I began researching online and thought that I would start with YouTube videos since they were always the first hits that came up. I also looked at tons of amateur instructional websites.
I went ahead and purchased a small kiln & two propane torches, beakers, glass rods, urea, fluxes, pure tin, sodium metabisulfite, Muratic acid & Hydrogen Peroxide, and I ordered a 2l bottle of regents grade 70% nitric acid. I have gloves, goggles and masks. I also have several paper filters and strainers, including a 5 quart colander bowl that I can but giant 3gal coffee filters in. Add all this to tongs, testers, scales, etc. Yea, I went kind of nuts with the credit card.
My work area is outside. I live on 5 acres surrounded at least 40 acres of woods. The nearest neighbor is well over 500' away with lots of trees in between. I keep at least 30' from the house and have a 32" commercial fan blowing across the area where I'm cooking. The area I work in is a clearing of an acre where my house sits. No
Now that I'm all invested I realize that almost everything I learned on YouTube is wrong, at least when it comes to safety. Man am I glad I found this forum.
I watched people working with nitric acid fumes in garages right next to their cars, even one where the person holding the camera was coughing and complaining about the fumes or the guy was hacking while pouring in the acid. I saw people refining in the basement, pouring acid into hot water, wearing paper painting masks or swearing that a P100 filter was more than enough. I even saw one where the guy had a mask hooked to an air compressor. No filter, not a breathing compressor, just a rusty old Craftsman garage style compressor. I now wonder how many people are dead because of this.
I figure I'm only going to be a casual refiner. Currently I have around 6 ounces of various karats of solid gold scrap (dental and jewelry) that I would like to eventually purify, plus several handfuls of plated jewelry that has no value other than scrap. Once retirement kicks in I'll probably only be refining gold from metal detecting jewelry and panning. I have pounds of plated silver - not sure if I want to tackle stripping that though, at least not at this point.
I've been experimenting with small batches outside. The other day I wanted to see how nitric acid would work on gold plated electronic pins that HCl and H2O2 would not lift the gold from. I used a 1000ml beaker with 200ml HNO3 which covered the 1/2 of pins in the bottom. This was placed on a warming plate (always outside). At one point I was about 15' away and I smelled chlorine for a few seconds. Not real strong nor did it irritate - I would compare it to not much more than when you go to a public pool when they just treated it. I'll be neutralizing this with urea today to see what my results are.
Question: if I get a whiff of chlorine even though I'm a good distance from the HNO3 is this something to be greatly concerned about? There was just a few seconds of the smell but it still raised a red flag for me.
Question 2: This is really a noob question and doesn't fall under the safety category but with things like the gold plated pins or plated jewelry why can't one just use aqua regia to dissolve the gold? I can see where other metals can cause headaches but once I recover what turns out to be 80-90% purity why can't I smelt it with flux and then re-refine it? I bring this up with pins because I saved a coffee can of gold pins (new) from the garbage and I use them for my experiments with various ratios of acid compounds. For the most part nothing seems to fully lift the gold - at least when HCl is involved.
I'm still unsure if I'll build a fume hood as I'll likely only be refining once or twice a year max - enough to produce a few grams of pure gold. I also learned on this board that no free standing mask will offer full protection from nitric acid fumes. You folks seem to be the only ones who knew enough to prove this.
As for the YouTube videos... most of them are so casual with the fumes which is really a concern. At least they all wore gloves, though a lot of them just used disposal latex ones - something I found were pretty useless if you were handling electronic scrap.
Yesterday I downloaded the Hoke manual. I was up to 3am reading it last night.