Thermal and Chemical Delamination: Recovering Silver and Silicon from Old Panels

… more less Thermal and chemical delamination split an old panel's laminate apart so that silver and silicon can be recovered. In the thermal route, the laminate is heated to roughly 500 C. The plastic encapsulant burns or breaks down into gases, freeing clean glass and the cell pieces. If a fluoropolymer backsheet is still attached, it releases HF and other fluorine gases. So it is peeled off first, or the exhaust is scrubbed. In the chemical route, solvents swell the encapsulant until the layers come apart, which is slower and makes solvent waste. Next, the cells are treated with acid. Nitric acid dissolves silver: 3Ag + 4HNO3 -> 3AgNO3 + NO + 2H2O. The silver is then won back, for example by adding salt to make solid AgCl. Note that this step releases NOx, which must be scrubbed. Other acids or bases strip off aluminium and the nitride coating, leaving silicon. Recovered silicon is rarely pure enough for new cells, so it usually goes to metal alloys. The trade-off is cost. These routes use energy and acids and pay off mainly through silver, while panels carry less silver every year. After this Concept you can describe how silver is pulled from an old panel and weigh its value against the fumes and acid waste it creates.