The latest LCD panel recycling system can reduce h

The new LCD panel recycling system can reduce the harm and protect the environment

with the dependence of household users on electronic devices and the increasing popularity of vehicles equipped with liquid crystal display (LCD), once these devices are no longer used, reducing their impact on the environment after entering the new normal begins to become increasingly important

previous studies have proved the harmfulness of liquid crystal, indium and other heavy metals contained in LCD panels, but there is no solution suitable for recycling these panels at present

in this context, researchers at Taiwan Institute of Industrial Technology (ITRI) plan to develop a new LCD waste recycling system to change this situation. The system is cost-effective, does not produce any waste, and allows manufacturers to save and reuse some valuable heavy metals for the production of LCD panels. The system department realizes the recovery of liquid crystal, indium and glass by integrating sequential separation, ppb level purification and nanopore technology

liquid crystal is a synthetic chemical with high unit cost and high stability, which is not easy to realize biodegradation. The liquid crystal structure contains a lot of benzene rings, fluorine, chlorine and bromine. If buried, it will penetrate into the groundwater system and affect the ecosystem

itri researcher Chien Wei Lu said: "Although the liquid crystal panel is only a few millimeters thick, it contains more than ten kinds of materials, which makes it particularly difficult to process and recycle when the preload P is 1kn. We have deeply analyzed the characteristics and reusability of each material in the LCD panel, and designed a logical separation program according to the correlation between each material: first, separate the liquid crystal, indium and glass materials, and then develop different purification technologies for each material, so as to realize these materials Reuse of materials. " The method starts with the panel crushing system, which can crush the LCD panel and then expose the liquid crystal material in the panel. Then, the separated LCD panel enters the continuous liquid crystal extraction system, and the liquid crystal can be extracted by specific reagents in multiple cycles. The liquid crystal is exposed on the surface of the glass substrate, which enables the system to shorten the processing time by integrating extraction and purification functions. The impurities can be removed by salt adsorption. After the liquid crystal is removed, the panel fragments enter the indium extraction system, and indium can be removed from the panel fragments through the repeated use of the scrubbing agent. The precipitate containing indium is dissolved with reagent and enters the indium concentration system, and then its concentration is realized through the precipitation principle

after removing most of the materials, the collection process of glass 9 composed of SiO2, Al2O3, B2O3 and other alkaline earth metal oxides began. According to the required measurement range of the sample, the glass was collected. The liquid crystal extracted by this new method can be reused, so that indium and liquid crystal glass materials can be recycled. Extracting liquid crystal from waste liquid crystal panels can achieve nearly 100% liquid crystal recovery and 90% indium recovery. This process can reduce the production cost of new liquid crystals and reduce the impact on the environment

harm of LCD panels

previous studies have shown the harm of liquid crystal, indium and other heavy metals in LCD panels. If organisms ingest fat soluble liquid crystals, they are likely to be stored in organisms without metabolism, leading to various organ diseases. If incinerated at a sufficiently high temperature, the liquid crystal may turn into CFC and destroy the atmospheric ozone layer; If burned at low temperature, the liquid crystal may turn into dioxin, PCB, hydrochloric acid or hydrofluoric acid, which are the culprits of environmental pollution

in the conventional physical treatment of liquid crystal panel, the plate must be broken and then added to cement or concrete, but this method cannot remove liquid crystal, indium, tin, molybdenum and other materials in the liquid crystal panel. Therefore, after rain erosion, liquid crystal materials and heavy metal materials may cause serious environmental pollution because the relative humidity is directly related to temperature

many countries and regions label LCD panels as hazardous waste. This situation requires the on-site disposal or burial, burning or physical disposal of LCD panel waste, but this increases the treatment cost and the risk of environmental damage

in order to test this new technology, ITRI has established a pilot plant, which can process about 3 tons of liquid crystal panel waste every day and produce 3 kilograms of liquid crystal, 750 grams of indium and about 2550 kilograms of glass, which can be used as green building reuse or heavy metal adsorption materials

it is estimated that North America produces hundreds of thousands of tons of LCD panel waste every year. Therefore, the effective treatment of LCD panel waste is urgent