It's been 30 years ago, in the Silicon Valley. Homick worked for a man that later became my partner. Homick's background was in printed circuits. I have never met him. I can't even remember my partner's name - the partnership didn't last long. All I remember is, that my partner went to a Rosicrucion temple and that he read palms in bars to get women.
I have recovered the gold from many iodine strippers used in electronics manufacturing, but I've never used the stripper, itself. I was very satisfied with cyanide. One of the beauties of cyanide is that you can destroy it. Until today, I hadn't read the iodine patent in 30 years.
A fume hood would be adequate. A good fume hood requires at least 100 cfm per sq.ft. of open area. Since iodine and chlorine are both halogens, I would expect a similar strong odor. Just a little bit would probably notify your nose that you were breathing the fumes.
You're right. The best things about this are that you can reuse it and that it's reasonably non-toxic.
You might have trouble using this on placer gold. Unlike plated gold, it always has some Cu, Ag, and other stuff alloyed with it (usually from about 2% to 35%, total). I2/KI is quite selective towards gold. It may, or may not, dissolve the particular alloy. Test with very small experiments. Also, rinsing would be critical, in your loose materials. Poor rinsing loses I2. You probably should save your rinses for I2 recovery.
The buffer thing is vague. It, as buffers do, mostly eliminates the need for pH adjustment. However, you have to start somewhere. Maybe, 1 or 2 ozs/gallon for start-up. A buffer is a buffer. Between certain concentration limits, you will get the same pH buffering (stability). He says the best pH is between 6 and 8. Check it after adding the buffer. You probably need a meter.
He also doesn't tell you how to extract and collect the iodine, for making up a fresh solution, when the Cu, Ni, etc., gets too high. I would guess you use distillation.
I have recovered the gold from many iodine strippers used in electronics manufacturing, but I've never used the stripper, itself. I was very satisfied with cyanide. One of the beauties of cyanide is that you can destroy it. Until today, I hadn't read the iodine patent in 30 years.
A fume hood would be adequate. A good fume hood requires at least 100 cfm per sq.ft. of open area. Since iodine and chlorine are both halogens, I would expect a similar strong odor. Just a little bit would probably notify your nose that you were breathing the fumes.
You're right. The best things about this are that you can reuse it and that it's reasonably non-toxic.
You might have trouble using this on placer gold. Unlike plated gold, it always has some Cu, Ag, and other stuff alloyed with it (usually from about 2% to 35%, total). I2/KI is quite selective towards gold. It may, or may not, dissolve the particular alloy. Test with very small experiments. Also, rinsing would be critical, in your loose materials. Poor rinsing loses I2. You probably should save your rinses for I2 recovery.
The buffer thing is vague. It, as buffers do, mostly eliminates the need for pH adjustment. However, you have to start somewhere. Maybe, 1 or 2 ozs/gallon for start-up. A buffer is a buffer. Between certain concentration limits, you will get the same pH buffering (stability). He says the best pH is between 6 and 8. Check it after adding the buffer. You probably need a meter.
He also doesn't tell you how to extract and collect the iodine, for making up a fresh solution, when the Cu, Ni, etc., gets too high. I would guess you use distillation.
