Improper disposal of old phones, computers, printers etc. is a big problem for the environment and human health. These instruments contain many precious metals like gold, silver and copper. Harmful methods are adopted in the unorganized sector to segregate these metals from electronic waste. Indian scientists have developed a method with the help of which e-waste can be recycled without harming the environment.
Scientists from National Institute of Technology (NIT), Mizoram, CSIR- Institute of Minerals and Materials Technology (IMMT), Bhubaneswar and SRM Institute of Science and Technology, Modinagar have collaborated with Microwave Incubation to extract precious metals like gold and silver from e-waste. A new method has been developed by combining processes like Incubation and Acid Nitrogen.
This new method works in seven steps. First of all, e-waste is heated in a microwave furnace at 1450-1600 degree centigrade temperature for 45 minutes. After heating, the molten plastic and metal slag are separated. After this, chemical separation of common metals is done with the help of nitric acid and precious metals with the help of aqua regia. Concentrated Nitric Acid is purified by removing metals and removing the deposited metals.
The e-waste used in this study while heating e-waste in a microwave furnace includes integrated chip (IC), pogo pins, metal wires, epoxy base extracted from scrap print circuit boards (PCBs) of old computers and mobiles. Electronic materials such as plates, electrolyte capacitors, batteries, small transformers and plastics were included.
During the study related to this, 20 kg of e-waste was first heated in the microwave and then acid refinement was done. About three kilograms of metal products have been obtained from this. In these metals, 55.7 percent copper, 11.64 percent iron, 9.98 percent aluminum, 0.19 percent lead, 0.98 percent nickel, 0.05 percent gold and 0.05 percent silver have been found. In this process electricity consumption is also very less.
Dr. Satya Sai Srikanth and Dr. Bijayananda Mohanty and lead researcher Rajendra Prasad Mahapatra told India Science Wire that ‘e-waste is quite different from domestic or industrial waste in chemical or physical properties. Along with being hazardous to organisms, the maintenance of e-waste is challenging. Typically, to obtain precious metals from e-waste, a Separation process is used with a muffle furnace or plasma method.
Dr. Sathya Sai Srikkanth and Dr. Bijayanand Mohanty
According to two other senior scientists associated with this study, ‘This newly developed method of microwave energy compared to conventional methods is one that reclaims precious metals from e-waste at lower time, lower power consumption and relatively low temperature. Has emerged as an environmentally friendly, clean and economical process.
The researchers included Rajendra Prasad Mahapatra, Dr. Satya Sai Srikanth, Dr. Bijayananda Mohanty and Raghupatruni Bhim Rao. This study has been published in the research journal Current Science.
(Sincerely to India Science Wire)