Study on the Volatilization Behavior of Heavy Metals (As, Cd) During Co-Processing in Furnaces and Boilers

摘要

Volatilization characteristics of arsenic (As) and cadmium (Cd) in different furnaces (sintering machine, blast furnace, boiler, and coke oven) were simulated. As and Cd in different chemical forms (As2S3, CdO, CdS, CdCl2) were co-processed with different raw materials and atmosphere in an electric heating tube furnace. The amount of As and Cd volatilized increased with increasing temperature and residence time. However, volatilization of As decreased as temperature increased in the sintering machine. The amount of Cd volatilized in the blast furnace in a reducing atmosphere was higher than that in the sintering machine with an oxidizing atmosphere. The amount of CdCl2 volatilized in different furnaces was high, but low for CdS. Kinetic models on the volatilization of these compounds during co-processing with raw materials were obtained under non-equilibrium conditions. These models can provide a preliminary theoretical basis for predicting the release of heavy metals (Cd, As). Also, we can determine which hazardous waste (HW) and furnace is suitable for co-processing, and the feeding rate or feeding point for the HW.