title: Study on the waste liquid crystal display treatment: focus on the resource recovery.
abstract: A process combined pyrolysis and acid immersion was proposed in this study to dispose the hazardous liquid crystal display (LCD) waste for recovering valuable resources. The thermogravimetric (TG) analysis and fixed bed pyrolysis were investigated for the polarizing film that was separated from LCD. The results suggested the liquid product mainly contained acids, esters and aromatics should be upgraded such as hydrotreating process before used as industrial feedstock or fuel source. The gaseous product mainly consisted of H(2), CO, CO(2) and CH(4) can be used as a valuable fuel. The sulfuric acid immersion experiments were studied for recovering indium from the LCD glass after stripping the polarizing film. Central composite design (CCD) under response surface methodology (RSM) was used to optimize the acid immersion process and the results indicated the indium recovery can be fitted based on the actual value to a polynomial quadratic equation and the temperature was more essential factor than time and acid concentration in the studied ranges. The optimum processing condition was obtained with time 42.2 min, temperature 65.6 °C and acid concentration 0.6 mol/L. Under the optimal conditions, the indium recovery was close to 100%.
authors.affiliation: Department of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China. wxysummerno.1@163.com
authors.forename: Xinying
authors.initials: X
authors.lastname: Wang
authors.forename: Xuebin
authors.initials: X
authors.lastname: Lu
authors.forename: Shuting
authors.initials: S
authors.lastname: Zhang
mesh_terms: D003247:Conservation of Natural Resources; D006256:Hazardous Waste; D006358:Hot Temperature; D007204:Indium / Q000737:chemistry*; D007220:Industrial Waste; D050866:Liquid Crystals / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry; D018505:Waste Management / Q000379:methods
chemical_list: D006256:Hazardous Waste; D007220:Industrial Waste; D013464:Sulfuric Acids; D007204:Indium; C033158:sulfuric acid