Recovery of indium from LCD screens using mechano-physical pre-treatment
Uwaoma, Andreas (2018)
Diplomityö
2018
School of Energy Systems, Konetekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2018100137013
https://urn.fi/URN:NBN:fi-fe2018100137013
Tiivistelmä
Recovery of indium from secondary sources such as LCD screens has become important due to the European commission’s classification of indium as a critical raw material. Current methods for the recovery have proven unsustainable due to the enormous amount of chemical waste associated with the extraction. In this thesis, we study the separation of the indium-tin-oxide (ITO) layer using different mechano-physical pre-treatments. Four different pre-treatment approaches were applied in the extraction. Heat, plasma, laser, and no pre-treatment prior to mechanical abrasion by a powered brush. The powdered extracts recovered was leached for indium using common mineral acids within technically feasible conditions. Attention was also paid to the economic feasibility of each method against the current market price of indium.
The Indium recovered was concentrated from 0.02 wt.% common in the conventional process to between 7.54 - 15.58 wt.% using the mechano-physical methods. The purity of the indium was up to 93 % and it had a significantly low iron contamination at 0.72%.
Although physical pre-treatment improves the concentration of indium, the cost of the treatments per square-meter of treated of LCD glass makes plain mechanical abrasion a viable alternative.
The Indium recovered was concentrated from 0.02 wt.% common in the conventional process to between 7.54 - 15.58 wt.% using the mechano-physical methods. The purity of the indium was up to 93 % and it had a significantly low iron contamination at 0.72%.
Although physical pre-treatment improves the concentration of indium, the cost of the treatments per square-meter of treated of LCD glass makes plain mechanical abrasion a viable alternative.