Gold From PET Rolls
Challenge
Recoup and recycle gold from PET (Polyethylene terephtalate), where the gold layer is naked – the plastic strip with gold layer on top is used in the medical industry. Compare the precious metal yield results by current supplier to our new patented solution.
Deposition
Gold
Substrate
PET polymer
Results
Our new solution was able to provide 52% to 45% higher yield in gold than the current supplier, while providing a certified 99.99% gold purity.
One of the major players in medical market supplies, analyzed the amount of gold (gold yield) that was being returned from the processing of their Au-PET films, by their vendor, a major refiner of precious metals.
The refiner provided their results in percentage of returned precious metals, the medical market supplier was interested in comparing real yields of gold (amounts of gold) with and outside company and turned to us for help.
The gold comparison was standardized by comparing the amount of gold in troy ounces returned for every 200 pounds of Au-PET foil by both the refiner and us.
The major difference between us and the vast majority of refiners who incinerate (burn the plastic film down) the PET and then extract the gold particles from the resulting ash, is that we directly dissolve the gold from the PET (i.e. we skip the incineration step).
We were informed that the average amount of gold, being returned by their current refiner was between 3.376 and 3.537 troy ounces per 200 pounds of PET, during the entire customer-supplier relationship to-date.
Our yield was 5.123 troy ounces of gold per 200 pounds of PET foil, which is between 52% to 45% higher than their current supplier, while providing a certified 99.99% gold.
It was of interest to both the customer and us why there was such a large difference in yield of gold. Especially since their refiner/vendor stated that their return was 98% of the recycled gold?
Since the incineration is (1) carried out at high temperatures, (2) oxygen is used, and most importantly (3) thin layers of gold are involved, we believe that the FIRST LOSS of GOLD at the refineries is due to these factors. Further, that perhaps thin layers of gold behave quite differently than chunks of gold during the incineration?
The next step in the process is to dissolve the gold (extraction) in liquid chemicals (i.e. aqua regia), leaving the ash behind (undissolved). This we believe is cause for the SECOND LOSS of GOLD. Especially, since the surface area of the ash is huge and some gold is going to stay undissolved and the amount of gold that is left behind is difficult to control.
Since our new technology skips the incineration of the plastic (the PET film), we do not have the “FIRST LOSS” of gold particles at all.
Our process directly dissolve (etches away) the gold layer from the PET surface at room temperature in a way that the PET film can actually be used again and recouped.
Also beneficial with our process is no ash is involved in our technology, so we can visibly control if any gold is or is not left behind (undissolved)
The customer was extremely pleased by the increased yields of gold obtained.