Basically, Au, Ag, Sn, Pd,Cu is probably the right sequence of commoditi
es value in e-scrap material recycling
. which metal to recover is usually depends on operator's facility and technical capacitie
s etc.
Eco-goldex provides a sequentia
l stripping procedure that will help operation to recover multiple metal commoditi
es in sequence:
- Surface Au-Ag-Pd stripping
Surface Au-Ag-Pd refers to those precious metals that are plated on the surfaces of electroni c component s such as the golden fingers on RAM, the pins of CUP, connector s, all kinds of pins and the plated wide print circuits on telecom board.
these surface gold/silver/ palladium can be easily stripped off with eco-goldex E series agent solution. - Solder Stripping
Many recycling operators haven't noticed the economic importanc e of solder in e-scraps. solder (mainly composed of Tin(Sn) and some Ag and Pb) can be easily recovered through either hydrometa llurgical method or thermal process (heavy smoke pollution). Eco-goldex provides its own hydrostri pping method that can easily strip Solder on PCB, at the same time to loose those component s attached on PCB such as IC chips, capacitor s.... most of the component s will fall off the PCB. After the solder stripping step, the PCB will become bare boards. these bare PCB can be either further crushed and pulverise d to recover copper and epoxy/plastic fibres that can realise zero disposal in the recycling process. the pop off component s will then pass a screening mechanism that sort different component s into different slots. one of the slots will receive IC chips. - Internal Au-Ag-Pd leaching
The IC chips collected from solder stripping step are then crushed and pulverise d into about 200 mesh powder. the IC chips powder is then leached in an agitating tank in there gold/silver fine particles will be leached out into solution. through a compressi ng filtratio n process, pregnant solution from the leaching solution will be separated from the IC hips powder sludge. the pregnant solution is then sent back to electrowi nning machine to recover gold/silver/palladium.
Eco-Goldex has analysed gold/silver/palladium grades in several different common IC chips and bare PCB boards after stripping
. Results indicate that all the IC chips container high grade gold, some of them contain considera
bly high silver. palladium grade is not impressiv
e or a that high as claimed by some operators
. our conclusio
n is that for most of the hobbyists, it will be good enough to recover Au-Ag, Pd can be counted as a credit if process quantity of high. the bare PCB has not significa
nt value since Au-Ag-Pd are low.
Below is table showing assay results of Au-Ag-Pd (all in ppm unit) grade in various IC chips. These IC chips powder are digested in AR to ensure all metals are completel
y dissolved
. AR solution is then assayed for Au-Ag-Pd concentra
tion with AAS (Atomic absorptio
n spectrome
try).
