Leaching of indium from obsolete liquid crystal displays: Comparing grinding with electrical disintegration in context of LCA

In order to develop an effective recycling system for obsolete Liquid Crystal Displays (LCDs), which would enable both the leaching of indium (In) and the recovery of a pure glass fraction for recycling, an effective liberation or size-reduction method would be an important pre-treatment step. Therefore, in this study, two different types of liberation methods: (1) conventional grinding, and (2) electrical disintegration have been tested and evaluated in the context of Life Cycle Assessment (LCA). In other words, the above-mentioned methods were compared in order to find out the one that ensures the highest leaching capacity for indium, as well as the lowest environmental burden. One of the main findings of this study was that the electrical disintegration was the most effective liberation method, since it fully liberated the indium containing-layer, ensuring a leaching capacity of 968.5 mg-In/kg-LCD. In turn, the estimate for the environmental burden was approximately five times smaller when compared with the conventional grinding.

► Two pre-treatment methods, prior to leaching of indium from obsolete LCD modules, were described.
► Conventional grinding and electrical disintegration have been evaluated and compared in the context of LCA.
► Experimental data on the leaching capacity for indium and the electricity consumption of equipment were inputted into the LCA model in order to compare the environmental performance of each method.
► An estimate for the environmental performance was calculated as the sum of six impact categories.
► Electrical disintegration method outperforms conventional grinding in all impact categories.