WP 6A Existing/potential industrial symbioses

Waste streams from LCD production

LCD panels (laptop) Indium co-mining with Zinc –further elaboration? Use of waste organic solvents Other industries As alternative fuels Use of spent acids as nutrient for biological wastewater treatment system, as incinerator dust heavy metals chelating agents, and flame retardants

LCD panels (laptop) Glass: Array/CF scrap glasses and cell glass trimmings (without liquid crystals but with some conductive materials) Ceramic and handicrafts. Aggregates in construction (according the the building standard, the concentration of glass is required to be lower than 20%) Glass contaminated with LC (hazardous waste) – option for recovery?

LCD scrap panels Dismantling and: Metal parts such as bezel front and bezel back are sent to metal recyclers plastics such as polarizer are sent to the external plastic recyclers. Backlight units, including light source Cold Cathode Fluorescent Lamps (CCFL), are being shipped to the mercury treatment company.

Sludges from LCD panel production Organic sludge, inorganic sludge and calcium fluoride sludge dried and mixed with sandstone or chelating agent to become additive for cement, concrete, road materials. organic sludge can also be used as organic fertilizer (if toxicity low) If not allowed – landfilled - TFT-LCD industry is actively exploring the alternative approaches of reusing organic sludge – ideas?

Silicon and integrated circuits (IC)

Symbioses Silicon of variuls sources can be used in PV modules production Chemicals: ammonia-peroxide, hydrogen chloride-peroxide, sulfuric acid-peroxide, hydrogen fluoride, nitric acid, tetrafluormethane as well as metal solutions for the patterns. To produce ICs, the solutions need to be very pure (high recycling and reuse) – possible increase through symbiosis?

Symbioses Defect IC already recycled and metals recovered – any potential to improve? Defect hard discs drives: Wongpanit offers roundabout 30 different fractions from HDD disassembly, including several qualities of gold containing flexible PCB cuttings, and read-write arms in different sizes, although reuse of these components is not confirmed. Platters are sold as “aluminium platters”, so the contained precious metals are obviously not recovered (loss of valuable resources) – any potential to improve?

PV modules – wafer cleaning Flushing in de-ionized (DI) water, if necessary addition of dissolvers. Wet chemical oxidation of the surface using a H2SO4/H2O2/H2O Surface etching using HF at 25°C. Remove of metal contaminants in a HCl/H2O2 bath at 75-80°C. Flushing in DI water Etching in a strong alkaline.