Friends, though it's my first post here, I really need your help. I just discovered this board :roll:
We are trading e-waste in South East Asia, and recently we are getting many unpopulated, production scrap (pics attached on the bottom).
We need to offer our price for it, but it's tough for us to estimate the content. We're given the sample, but it's too small to do the actual test.
So, what I'm trying to do is get a very conservative estimation of Au content. Would you please quickly go through my estimations below? Do they make sense? Again, I can underpay for this material, so if I'm too conservative somewhere it's ok. I need to make sure I'm not too optimistic... Thanks!
Here's how I go about it:
1. 12 little rectangular boards per set, conservative assumption that each board is 10% gold plated on both sides. Weight of each set is 122g.
2. Each little board is 6.4cm by 4.4cm, therefore gold plated area is 6.4*4.4*0.1*2=5.632cm^2 of gold plating per little board or 5.632*12=67.58cm^2 of gold plating per set, including both sides.
3. Assume that this is class 00 (is it still the lowest?), so 20 micro inches thickness of the coating. In cm it gives me 0.0000508cm. Therefore volume is 67.58*0.0000508=0.00343cm^3. Since each cm^3 of gold is 19.3 grams, we have 0.0633 grams of gold per set.
4. Since each set is 122g and 1 ton is 1000000 grams, I have 1000000/122=8196 sets per ton. Therefore I have 8196*0.0633=519g of gold per ton of this material. To add a safety factor of 0.8, I get roughly 400 grams per ton.
We are trading e-waste in South East Asia, and recently we are getting many unpopulated, production scrap (pics attached on the bottom).
We need to offer our price for it, but it's tough for us to estimate the content. We're given the sample, but it's too small to do the actual test.
So, what I'm trying to do is get a very conservative estimation of Au content. Would you please quickly go through my estimations below? Do they make sense? Again, I can underpay for this material, so if I'm too conservative somewhere it's ok. I need to make sure I'm not too optimistic... Thanks!
Here's how I go about it:
1. 12 little rectangular boards per set, conservative assumption that each board is 10% gold plated on both sides. Weight of each set is 122g.
2. Each little board is 6.4cm by 4.4cm, therefore gold plated area is 6.4*4.4*0.1*2=5.632cm^2 of gold plating per little board or 5.632*12=67.58cm^2 of gold plating per set, including both sides.
3. Assume that this is class 00 (is it still the lowest?), so 20 micro inches thickness of the coating. In cm it gives me 0.0000508cm. Therefore volume is 67.58*0.0000508=0.00343cm^3. Since each cm^3 of gold is 19.3 grams, we have 0.0633 grams of gold per set.
4. Since each set is 122g and 1 ton is 1000000 grams, I have 1000000/122=8196 sets per ton. Therefore I have 8196*0.0633=519g of gold per ton of this material. To add a safety factor of 0.8, I get roughly 400 grams per ton.