The specific news item that triggered this Display Daily column was a report by a team of researchers led by Professor Hiroyuki Yoshida of Osaka Prefecture University and Sharp Corp. They have developed a new technology that enables the reclamation of approximately 95% of the indium in a LCD.
Insight Media Consultant
The first part of the reason that this is important is that indium is a key ingredient a wide range of electronic devices and components. This not only includes LCDs but also plasma displays, LED and lasers. Indium is also used as a coating in many other applications including heat reflecting windows and solar cells.
The second part of the reason is that, as a result of the high demand, the price of indium has increased dramatically in recent years. As recently as 2002, indium sold for $97/kg. By 2006, it had skyrocketed to $980/kg. Although the price of indium did drop considerably during 2007 and 2008, experts predicted no long term relief. That has turned out to be the case. Traders report that price of indium on the European spot market has gained 65% since the middle of July increasing to $520/kg.
The price run up has been driven by fears of a shortage. These fears derive from that fact that China is the world’s largest supplier of indium and China had stopped almost all indium production. The reason for this is that the main indium production center in Hunan province has embarked on a campaign to address the hidden environmental costs associated with a range of industries including metal smelters.
The third part of the reason is that consumer electronic products that contain indium are usually discarded in an intact condition. This means that e-waste represents a sort of "urban mine," a potential source of indium that is currently almost untapped.
Based on these three reasons, it follows that technologies that can recover the metal from used appliances are much sought after.
In reviewing the literature we find that several methods have been proposed for reclaiming indium from scrap electronics. A process developed by researchers at Institute of Multidisciplinary Research for Advanced Materials at Tohoku University in Japan is based on a procedure by which LCDs are ground in a ball mill together with silicon. Chemicals such as hydrochloric acid are used to extract In2O3. High purity indium powder is recovered by using a non ferrous metal separator. Another process uses bacteria.
The new technology breaks the glass substrates into small pieces and submerges them in a sodium hydroxide solution. After processing the mixture at a high temperature and pressure to reach a sub-critical state, the indium is removed from the glass substrates.
The new technology is claimed to be sufficiently simple to have the potential of reclaiming indium at an attractively low cost. The next step in the developer’s plan is to further investigate the operating efficiency and cost effectiveness the process. To that end, the plan is to build a continuous processing device based on the technology. The prototype will be installed in an ecology laboratory in the Sharp Green Front Sakai, an LCD manufacturing facility in Osaka Prefecture.
A cost effective method to recover the indium from scrap LCDs can be an important part of the means by which industry assures an affordable and continuous supply of indium - while at the same time providing the environmental benefits of recycling. It is the stated goal of all parties involved with the new indium reclamation technology to commercialize it as quickly as possible.
And by the way, recycling and reclamation of display-based components was discussed this week at the world’s first conference dedicated to the green display ecosystem. Look for more information soon on the availability of proceedings from the Green Display Expo and Insight Media’s new report on Green Displays.