Testing Black Chips and SMD Packages on their Raw Gold Content Roy Eugster, Switzerland, April 2013

Treatment of Chips for Gold Extraction

1. Prepare chips burning with a butane/propane torch until all organic material have gone. Best to see when there is no more yellow flame and only the blue torch flame.

2. Final burning of this prepared chips (color greyish/white) in a muffle furnace at about 900°C for 15 to 30 minutes. The chips are then white and crumbly like the spanish "Polvorones".

3. Gently mill the white chips in a mortar without breaking the silicone chips.

4. Sieve the powder to remove silicon chips and pins.

5. Pass through the powder with a strong magnet (neodym) to remove iron/nickel particles and pins.

6. Eventually sieve the powder again to remove the remaining copper pins.

7. Wash the powder to remove the very fine dust. Maybe it is necessary to mill again.

8. Repeat step 7. until there are only the gold bond wires. Remove remaining copper/nickel pin pieces with acid (e.g. HCl with H2O2).

9. The resulting gold may have some unsoluble dirt but it's ready for further treatment (melting, refining, aqua regia processing, ...).

Results Batch Yield Ratio

Raw Gold /

Nr Weight Package Picture Raw Gold Batch Weight

11 50 g DIL8...20

0.0020 g 0.004%

12 25.6 g FCBGA-(A)

0.0596 g 0.233%

Nr Weight Package Picture Yield Ratio 13 30 g FCBGA-

(B)

0.1328 g 0.443%

14 50 g FCBGA-(C)

0.2212 g 0.442%

15 55 g FCBGA-(D)

0.1898 g 0.345%

Nr Weight Package Picture Yield Ratio 16 54 g FCBGA-

(E)

0.1506 g 0.279%

5 50 g PQFP100

0.0748 g 0.150%

9 50 g QFP20... 36

0.0349 g 0.070%

Nr Weight Package Picture Yield Ratio 2 100 g QFP68...

200

0.05 g 0.050%

1 70 g SOIC20, SO8...20,SOP14... 20

0.16 g 0.229%

8 50 g SOJ-W16...28

0.0251 g 0.050%

Nr Weight Package Picture Yield Ratio 3 50 g SOJ20...

28

0.04 g 0.080%

6 50 g SOJ44

0.0231 g 0.046%

10 50 g TQFP...64

0.1089 g 0.218%

Nr Weight Package Picture Yield Ratio 7 50 g TQFP68...

200

0.1302 g 0.260%

4 50 g TSOP44...54

0.05 g 0.0447 g

0.100% 0.089%