Research on the recycling technology of aluminum element from waste crystalline silicon cells

A wet chemical recycling approach was adopted， utilizing a potassium hydroxide （KOH） solution to leach the aluminum back-surface from solar cells. The influence of three key experimental parameters， the mass percentage of KOH solution， molar ratio of KOH to the aluminum back-surface in the cells， and reaction conditions on the leaching rate of the aluminum back-surface were investigated. A series of single-factor gradient experiments and cross-variable experiments were designed， covering KOH solution with a mass percentage ranging from 20% to 70% and solid-to-liquid ratios from 1∶10 to 1∶60， while controlling reaction conditions to determine the optimal parameters for aluminum back-surface leaching. The morphological changes and elemental composition variations of the aluminum back-surface before and after the leaching reaction were characterized using scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results demonstrated that the optimal leaching effect was achieved under the following conditions： KOH solution with a mass percentage of 20%， solid-to-liquid ratio of 1∶20， and reaction temperature of 70 ℃.