Sharp and Aqua Tech Co. Ltd. have jointly developed a proprietary technique to recover and recycle the rare metal indium from the transparent electrodes^* in LCD panels.

This new technique takes advantage of the unique properties of this metal. LCD panels are first crushed into glass cullet (small chips) and then dissolved in an acid solution. It is a simple process using common chemicals that eliminates the need for large energy expenditures, such as those required to achieve high temperatures or high pressures. Moreover, the indium metal recovered is of high purity.

Sharp will be conducting proof-of-concept tests using large-scale prototype equipment, and will move toward actual recovery operations. The aim is to establish a closed-loop recycling system for indium.

* The transparent electrode in an LCD is formed from a conducting film deposited on one of the glass substrates of the LCD. A voltage is applied at the required level to the liquid crystal material sealed between the two glass substrates. This causes the molecules of the liquid crystal to shift their orientation, thereby controlling the passage of light through the display.