Migration of inorganic chlorine during thermal treatment of mineralized waste

Abstract

Chlorine is a common element in the environment where it mostly exists in an inorganic ionic state that is highly mobile and non-degradable. It is important to investigate the potential release of chlorine into the environment from mineralized waste (MW) for stable landfill reclamation. In this study, inorganic chlorine in the MW migration process was explored during thermal treatment for chlorine pollution control. The temperature and chlorine greatly affected the distribution of inorganic chlorine in the thermally treated products. Below 800 °C, more than 60% of the inorganic chlorine remained in the bottom slag. Above 900 °C, volatilization caused the release of chlorine from the MW and more than 75% of the inorganic chlorine was deposited inside the furnace. The mass of inorganic chlorine deposited in the thermal treatment furnace was significantly correlated with the actual temperature. At 1000 °C, the masses of inorganic chlorine deposited under pyrolysis, incineration, and gasification atmospheres were 7.69, 5.81, and 5.68 mg, respectively. The greatest deposition of inorganic chlorine inside the furnace occurred during pyrolysis. The chlorine migration process must gain more sight during MW thermal processing.