Study On Recycling And Reusability Of Liquid Crystal From Wasted LCDs

As the terminal carrier of liquid crystal display technology,the market share of LCD is growing rapidly in recent years.A large amount of LCDs are scrapped every year.If it can be effectively recycled,it will not only reduce the harm of environment and human body,but also turn waste into treasure.In this paper,the liquid crystal in the TFT-LCD display is taken as the research object.Aiming at the shortcomings of the existing recycling technology,such as high labor and material cost,low efficiency and unsuitable batch production,the technology of reresource was studied.The main research work is as follows:(1)A special shearing and crushing machine for liquid crystal panel was developed.The structure and working principle of the crusher were expounded in detail,and the selection principles of the key parts were deeply analyzed,and the force-energy parameters were calculated.The relationship between the temperature field distribution and the broken process parameters of the LCD panels was studied.A simple,efficient,low cost and reliable low temperature crushing technology was proposed for wasted LCD panels.The low temperature cooling method was determined,the cheap and easy cooling medium was selected and the reasonable cooling temperature and cooling time were set.(2)The experiment of ultrasonic assisted mixed organic solvent to dissolve liquid crystal was studied.By means of single factor test,the optimal range of parameters affecting the test was determined,and the response surface method was used to optimize the dissolving condition.Then the experiment on the precipitation of organic impurities at low temperature was carried out to determine the temperature and time of the maximum precipitation of organic impurities.Finally,the recovery process and technological conditions of mixed organic solvent dissolution,separation of glass particles and solution,prefiltration and impurity removal,adsorbent adsorption and low-temperature precipitation and purification,and vacuum liquid-liquid separation were presented.(3)The main physical properties of the recovered liquid crystal were tested to determine its reusable value.The test results show that the physical parameters of the recovered liquid crystal can meet the requirements of the standard AM-LCD screen,and can be used in low-end display occasions such as game consoles,monitors and indusvtrial touch screen displays,etc.In this paper,we have innovated and improved the technology of liquid crystal recovery in the waste liquid crystal display screen,and presented a set of feasible recycling process,which laid a foundation for large-scale,industrialization,efficient and green recycling of the liquid crystal materials in the waste liquid crystal panels.