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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 H2, CO, CO2 and CH4 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 42.2min, temperature 65.6°C and acid concentration 0.6mol/L. Under the optimal conditions, the indium recovery was close to 100%. [Copyright &y& Elsevier]

Abstract: Liquid crystal display (LCD) glass mainly consists of polarizing film, liquid crystal and glass substrate. Removing and recovering the liquid crystal and films from the LCD glass effectively has important significance for recovering the other parts. This study proposed a pyrolysis process to recover the organic parts from LCD glass. Through thermal gravimetric analysis, the pyrolysis temperature of the LCD glass could be chosen at 850K. The removal rate of organic parts from LCD glass reached 87.87wt%. Pyrolysis products consisted of 66.82wt% oils, 21.01wt% gaseous and 12.13wt% residues. In addition, the oils contained 46.27wt% acetic acid and 32.94wt% triphenyl phosphate. Then, the pyrolysis mechanisms and products sources of the liquid crystal glass have been analyzed based on the information of bonds energy. The pyrolysis mechanism analysis proved that the products mainly consisted of acetic acid, triphenyl phosphate and C, which is consistent to the results of GC–MS analysis. A reasonable way has been put forward to recycle the pyrolysis products: acetic acid and triphenyl phosphate can be collected by distillation, the rest oils and gases can be used as fuel and the remained glass can be used to extract indium and to produce building materials. [Copyright &y& Elsevier]

Abstract: This study discusses the thin film transistor liquid crystal display (TFT-LCD) waste glass-blended cement (WGBC) pastes. It presents their compressive strength, their products of hydration and solid silicates changes. The samples were subjected to Fourier transformation infrared spectroscopy, differential thermal and thermo-gravimetric analysis and 29Si magnetic angle spinning/nuclear magnetic resonance. The experimental XRD results demonstrated the speciation of the TFT-LCD waste glass, and that the major component was SiO2. At 40% substitution of TFT-LCD waste glass, at 28 days and 56 days, the compressive strength was 35% and 30% lower, respectively, than that of the Portland cement paste. The intensity of the Ca(OH)2 band at 3710cm−1 in the 56-day hydrated products of the WGBC pastes that contain TFT-LCD waste glass exhibit comparatively weak peaks suggesting that much Ca(OH)2 during hydration was consumed. Later, the Ch name="sbnd" />H contents of the WGBC pastes increased, revealing that liberated Ca(OH)2 was consumed in pozzolanic reactions. [Copyright &y& Elsevier]