So... How much gold is there on them plated computer pins??
This question is impossible to answer defiantly.
One can only make estimations and educated guess, unless the appropriate spec sheets are available. With that said, assuming you have a homogeneous pile of gold plated pins (meaning same type and size of pins), you could take measurements of surface area and calculate.
for example: a. measure the surface area of one pin and take note. b. weight how many pins make up one gram. c. multiply this number (b) with how many grams of those pins you have. d. multiply this number (c) with the surface area of one pin (a) This calculation should give you a pretty close estimation of the gold plated surface area you have on your pins.
Now you need to know the thickness of the gold plating. Again, without a spec sheet, it is a guessing game.
But i can try and help you how figure it out so you could use some educated guess about the gold plating thickness. Notice the color, the more light and shiny gold color, usually means a lighter (thinner) plating. Consider the application for which the pins are designated for... the more demanding the environment it is supposed to function in, the thicker the plating will probably be. Such applications are usually the space industry, military and medicinal equipment, but not always though. - High end, thick gold plating is considered at 50 microinches and above. - Moderate gold plating thickness is usually 20-30 microinches. - light gold plating is usually at ranges of 10-20 microinches. - Flash plating is about 5-7 microinches thick. When all of the numbers are laid out, you can calculate the volume of the gold plating. You can also use my simple gold plating calculator for that calculation. By now, you probably realize that there are numerous variables that are sometimes unknown to you, therefore, finding a definite number for gold yields is an impractical quest. But a pretty close estimation can be achieved by using the simple logic described above. With that said, the actual yield results may vary to some extent depending on the recovery and refining methods chosen by the operator, as well as his expertise.
With assorted mix of pins, this mission of finding out how much gold is in the plating is absolutely impossible, and the answer will be given only after processing the pins with what ever recovery route chosen. This is why i always endorse a careful sorting and separation of the different scrap types. One must realize also, that some of the lightly gold plated materiel is just not worth processing and a careful consideration should be applied toward the ratio of base metals content and expected gold yield. There are numerous ways to treat and recover gold out of gold plated materials (e.g- jewelry, e-waste etc...) and i will share them with you when time allows, with the entire process described in details.