Detoxification of asbestos-containing waste using thermal-chemical treatment for cement production

Harmful asbestos-containing waste is generated during old building demolition. This study aims to develop a thermal-chemical treatment method to detoxify asbestos-containing waste and explore the potential use of detoxified asbestos-containing waste for cement production. Four weak acids including acetic acid, phosphoric acid, citric acid, and oxalic acid were employed under different temperatures, reaction times, and solid-to-liquid ratios for the removal of chrysotile, the major asbestos, in asbestos-containing waste. The optimal treatment condition for complete chrysotile removal was: 1 M oxalic acid, 200 °C, 2 hr and a solid-to-liquid ratio of 150 g/L. The estimated cost excluding capital and manpower investments was 100.7 USD /ton and the associated carbon emission was 113.68 kgCO₂e/ton, which were highly attractive compared to traditional solidification and landfill disposal. The addition of 5 % detoxified asbestos-containing waste did not alter the properties of cement raw materials or clinker. The initial setting time of cement mortars and the compressive strength of final cement products did not show significant differences from those of regular ones. The proposed thermal-chemical treatment can detoxify asbestos-containing waste for beneficial reuse, offering a sustainable way for asbestos-containing waste management and resource recovery.