Theoretical analysis and experimental study on the chemical removal of putty layers

Abstract The removal of plaster layers is predominantly manual, resulting in low efficiency and health hazards. While chemical methods are effective, they readily produce toxic gases and residues. To enhance efficiency and reduce corrosion and pollution, this study improves the chemical treatment method by employing low-concentration hydrochloric acid in experiments. Based on reaction mechanisms and factors such as H + concentration and volatility, 4%, 7%, and 10% hydrochloric acid solutions were selected for comparison, examining reaction time and removal efficacy. The results indicate an optimal reaction time of 30 minutes. A 7% hydrochloric acid solution offers higher safety, whereas a 10% solution demonstrates superior efficiency but also produces acid mist. Overall, the optimal concentration requires further optimisation in conjunction with mechanical assistance.