cjeh, this may not be what you want to hear, but I'm going to share my thoughts.
you mentioned in your first post that you have "a couple of pounds of gold and black sand". At 453 grams per pound, that's 906 grams, but let's round up to 1000 grams to make the math easy.
Based on the percentages you've just given, you might have 1.5 grams of copper, 0.2 grams of gold, and 0.05 grams of silver.
Other members have asked about an assay and mentioned nasty things that might be in your material. You've responded "My shop is well ventilated.I also have a large roll up door that can be used for additional ventilation." I fear you may not be taking the issue of safety seriously enough. There are two important reasons for getting an assay; 1 to find out if there are any values present, and 2 to find out what other dangerous elements may be present.
Justinhcase provided a link to a post made by another member who didn't listen to the advice to get an assay before he started roasting his ore. Barren Realms also referred to the thread, because the man nearly died and his health may never return to what it was.
Now just for the sake of argument, let's say that your roll up door and some fans will blow any toxic material out of your shop. Where? Who and what will you potentially poison with the toxins you vent out around your shop, and please don't dismiss the question by saying you don't have any neighbors near by. Heating your material can release toxins that can then enter the air, soil, and water, and that may remain after you move on.
The question is, is it really worth it to pursue this venture for the $8.31 worth of gold that might be in two pounds of material? I'm not trying to be mean, shatter your dreams, or discourage you from learning the art of recovery and refining. But I want you to step back and make a realistic assessment of whether the benefit is worth the risk. Only you can answer that question, but you can find that much gold in a couple of old computers.
Dave
