In our second update, we are happy to share our recycling progress as we managed to conduct our first e-waste recycling since January 2021! Based on the e-waste that we have collected, we sorted out particular type of e-waste that we can recycle in our facilities in Karawang, Indonesia. We focused on the 9 kilograms of feed which came from waste printed circuit boards. In summary, the recycling step consist of dismantling, grinding, density separation, leaching, and smelting. In this update, we have only covered the dismantling, grinding and density separation as our pre-treatment process due to time limitation. The final phase of recycling which are the leaching and smelting is scheduled for our next experiment. The first step of the pre-treatment was to dismantle the electronic components (IC chips) from waste printed circuit boards manually. We kept and stored the parts in our warehouse which we can not recycle such as the boards itself. We planned to send the unmanaged parts to small electronic manufacturers/traders. Next, the IC chips were grinded in a ball mill to liberate the metals from the impurities such as plastics and ceramics. Two steel bars were placed inside the rolling mill to crush and grind the IC chips. Small amount of water was added to reduce the generated dust during grinding. The grinding process last about 2 hours as the feed became pulverised. Due to the machine limitations and drawback, the recovery of the grinding process was about 50%. We produced about 1 kg of pulverised feed from 2 kg raw materials per batch. The last step of the pre-treatment was the density separation. Please see attached a photo of the shaking table we used to separate heavy particles from light particles. Water was flowing through the entire surface as the table vibrate hence the light particles will be swept away by the water to the bottom part and the heavy particles will flow along the table to the side. In principle, heavy particles consist of precious metals (Copper, Silver, Gold) while the light particles consist of plastics and ceramics/glass. We produced 3 output streams from our shaking table. The streams were “concentrate” (high-grade stream), “middling” (low-grade stream), and “tailing” (very low-grade stream). The grade is based on the concentration of the precious metals. We took and sent small amount of sample from our feed, concentrate, middling, and tailing for characterisation to a certified lab (PT Geoservices Indonesia). We would like to know the composition of our recycling input and output to further calculate the recovery and efficiency of our recycling process.
Our next plan is to continue the recycling experiment (leaching and smelting) to produce gold. We aim to at least recover 1-2 grams of gold from our concentrate. Please follow our Instagram (@id.remind) and check our website (https://www.remind.co.id/) to stay updated with our recycling activities!
