An ideal test situation: As would be carried out in a fully equiped, experienced and professional laboratory setting where one could assure that that the results would be consistant within +- 1% and that at least 99% of the existing gold could be recaptured and also after tallying the mean results of a half a dozen refines on the same type of product and with no spills, wastage, consistant measurements of processing chemicals used and post tests to assure that nothing is left in solution, etc... In other words a lab setting where the operators could state after the fact and within a 99% percent certainty that 99% of the existing gold had been recovered from the chip. Only then, could one be comfortable to state with high probability that a certain chip type or product contains on average x ammount and no more and no less...etc.
In another life many years ago I ran a chip mounting and gold wire bonding and ceramic package sealing and environmental test lab operation at Harris Semiconductor back in the early 80 s where I worked as shift supervisor over 60 proles and we inspected in clean room and then mounted the chips with gold solder into the ceramic cases, wire bound them with gold wire as fine as spider webbing thenand oven sealed the gold plated lids on and I can tell you that the tolerances, especially for Mil-spec parts, were very tight and variations of .25 grams of gold between parts of the same type did not exist nor would have even been tolerated since everything was computer controlled and the military was extemely tight on watching us and maintaining strict applications and audits at every level. I doubt if .0005 variances of the metal applied even existed given the digital levels of computer accuracy and daily calibrations of all processes. With commercial parts it was a little more loose but even then not to within the range of the refined gold(.50-.75) reported recovered by various contributors on this forum.
In my own three home lab tests of 6 pros each time, simply simply shattered with two or three hammer blows and then submerged in a nylon mesh bag in a quart of aqua regia overnight, I am barely recovering 3 grms pure gold post crucible.
Granted, my acetelyne cutting torch might be the wrong thing to use for melting and I suspect I might be blowing dust and even melted globules away since I weigh 8 or 10 dried grams of brown powder and end up with 3 grams of gold, so I have ordered a rose bud torch to see if that makes a difference. I have not been pulverizing the chips to powder either before placing them in the AR...although I am not sure if changing torches and pulverzing everything pre bath will raise my yield significantly either? A fellow in China wrote me he is getting 1 gram per pro chip but he is also using zinc dust to precipitate with instead of Sodium meta-bisulfite which is what I am using. After neutralizing one quart of AR with urea and adding 50 % volume in distilled water before shotting about 3 or 4 tea spoons of hot dissolved SMB into it, within 10 minutes I am getting a nice brown sprinkle of fall out and after about an hour that seems to be about it. No matter what I do after that I can not seem to squeeze anymore brown precipitant out of the clean pale green solution I have generated and so I do not know if I have gotten it all or if more is just locked inside and will not come out???. I then decant my solution to another big beaker and wash the brown residue remaining in the bottom of the first beaker about six times in distilled water then filter it off and dry it atop the filter paper and weigh it and make a note in my book. I then roll it in two sheets of toilet paper, dip the squib in alcohol and place it atop a bed of boric acid crystal flux in my crucible and heat it up until I see the glowing little bead rolling around in the flux. I then pour if off quickly into a container of cold water and take out my little gold marbles. Sometimes a silver colored marble comes out also which is composed of a very dense, heavy and white silver metal which will not mix with the gold and I have recovered about 1/3 as many of those nuggets alongside the gold ones. (not sure what they are though...paladium?)
Before placing my 6 hammer broken pro chips in the AR I weigh them and have 1 lb 2.5 oz of material. Post AR I rinse/ soak in bicarbonate solution for an hour and sun dry before physically touching them again and then weigh what is left of the chips. After AR I find that I have only 1 lb .40 oz of materal left...all ceramic except for the shattered glass processors inside which are still golden and which I have no idea how to extract the gold from.
This means that 65.31 grams of metal, or just over 2 oz of metal that was inside those chips has dissolved in the AR. Granted, a lot of that is probably the copper pins, etc....but to only get about 3 grams of gold out of all that which has dissolved is disturbing and I believe that the rest of it, or another 3-4 grams of gold is still trapped in solution along with the other 60 remaining grams of missing dissolved metal. Any thoughts on where I am loosing gold? Still in solution, not pulverizing the chips first or the wrong blow torch or something else I am missing altogether? Thanks JR
I would also like to believe like the China man says that there is 1 gram refinable in each of these pentium pro chips but right now I would also be happy just to increase my yield to .75. Thanks JR