The end-of-life liquid crystal displays (LCD) represent a relevant criticality for waste management since huge amounts of this waste are reaching the landfilling sites worldwide. This equipment is used in different devices (e.g., PC, Tv, notebook monitors) with an average lifespan of 6-7 years.
During the traditional recycling technology, after a first dismantling of the LCD, the resulting panel is disposed of as not-hazardous material, with a consequent loss of valuable materials. Indeed, this panel is composed of glass, the main component, and ITO, a film of Indium (90%) and tin (10%) oxides. The potential economic value of these fractions, combined with the need to decrease waste sent to landfilling sites, makes this innovative LCD recycling process essential for the development of circular economy strategy.
The identification of secondary resources of indium, defined as critical raw material by European Commission and currently extracted in Chinese mines, represents a priority. In this context, our invention shows an innovative method for the recovery of indium from LCD. The simple design includes a panel grinding followed by an acid leaching and a cementation process with Zn. The operative conditions (T 80°C, reaction time of few minutes) allow an indium recovery higher than 90% with low waste production, thanks to the exploitation of the solid residue as building material and an efficient wastewater recirculation system.
Patent Status
PENDING
Priority Number
102018000008207
Priority Date
28/08/2018
License
ITALY
Market
Indium is mainly used for LCD production and its use will grow for photovoltaic panel CIGS (Copper, Indium, Gallium , Selenite) manufacturing. The increasing interest for this topic is confirmed by the growing patent number (mainly Chinese patents), mainly with complex approaches. The annual Indium demand is around 62 t/year and 5 t/year in Europe and Italy, respectively. The average amount of the discarded LCD is around 57 kt/year and 6 kt/year in EU and Italy, respectively. Therefore, the possible exploitation of the whole LCD amount could cover the 20% of the annual Indium demand.
Problem
As described in the WEEE Directive (Dir. 2012/19/UE, D. Lgs 49/2014), LCD are first dismantled to remove the hazardous components and main fractions (such as steel, aluminium, plastics) are exploited. The end-of-life panel is currently not exploited and it represents a significant criticality for the waste management system: indeed, since a huge amount of this kind of waste is reaching the landfilling sites worldwide (around 25 million m2 of LCD per year in Europe).
On the other hand, it is estimated that the annual Indium demand will reach 25-50 ktons in the next years, to cover the future demand for both LCD and CIGS production.
Nevertheless, the mines (the main current indium resource) cannot support the further metal demand.
The need to decrease landfilled waste combined with the necessity of secondary indium production, makes the LCD recycling process crucial for the development of circular economy strategy.
Current Technology Limitations
Considering the LCD lifespan, huge amount of this waste will represent a significant problem for the SME involved in its management.
The current technologies focus only on steel, aluminum, plastics and glass exploitation. Some actual patents deal with Indium extraction from pretreated panels, combined with other fraction (e.g., liquid crystal). However, these patents report extreme leaching conditions, or require the use of raw materials considered hazardous for environment and health. A patent search has also evidenced that the whole value chain of LCD panel recycling, from the pretreatment to complete material recovery, is poorly considered.
The proposed technology includes all panel treatment step for the complete exploitation. The simple design and the relatively environmentally friendly operative conditions allow to apply this technology in SME recyclers premises. The process combines temperature lower than 80°C and leaching time of minutes. The short time and the complete waste exploitation diversify this patent from the others. The zero-waste approach of the present invention is applied both to solid waste (thanks to building material production) and wastewater (thanks to a wastewater recirculation program) that allow almost a complete self-water sustainability with a net process-water saving of at least 85%.
Killer Application
The present technology addresses every SME recycler that deals with electronic waste. Its characteristics of simplicity and versality, will allow to transform a waste into a resource, directly in the premises of the recycler. The process will provide a double solution: avoiding landfilled waste and providing new Indium reserves; also creating new job positions for the LCD panel exploitation. As concerns the final Indium product, a double market option exists: either purification or use as alloy for different applications.
Our Technology and Solutions
Currently, the end-of-life LCD is discarded as not hazardous material. However, the potential recoverable material within LCD, such as glass (the mainly LCD component) and ITO, a film composed by Indium (90%) and Tin (10%) oxides, push the research to develop new recovery technologies. The process proposed by the present patent allows to realize a zero-waste treatment, optimizing the leaching process with a new pretreatment and with the exploitation of the solid waste. The first step is a grinding process with high efficiency (LCD particle size lower than 1 mm), followed by a leaching step and with Indium recovery by cementation, The solid waste resulting at the end of the leaching step is used for the building material production.
This process show several advantages compared to others and it is considered as applicable by all industries in the WEEE management sector.
Advantages
The unique combination of the steps described above, provides the follow advantages:
Roadmap
This invention has recently obtained a grant from the Italian Ministry MiSE for the improvement of the technology readiness level from TRL4 to TRL6, under the same key conditions:
For the extension of the technology to photovoltaic CIGS panel and smartphone screens
For the assessment of the potential of a startup company, for the technological transfer to industries. In this subject, a SME recycler in Marche region, RIMEL S.r.l., showed its interest for the patent and is supporting the research providing the WEEE.
TRL
Team
