Starting Method of High Level Liquid Waste Rotary Calciner

In the two-step cold crucible induction melting vitrification process, the Leidenfrost effect can lead to the formation of a vapor layer on the furnace tube when high level liquid waste（HLLW） is introduced. This phenomenon occurs due to the high temperature of the rotary calciner, preventing the initial batch of liquid from fully evaporating and calcining. Additionally, excessive feed quantities increase the risk of high level liquid waste exiting the furnace prematurely. To address this, excess heat must be removed by introducing water(or high level liquid waste) before feeding the HLLW, a procedure known as the calciner start-up process. This study investigated the effects of three start-up media: water, diluted HLLW, and simulated HLLW at rotational speeds of 5 r/min, 15 r/min, and 30 r/min on both low- and high-temperature start-up processes. The results of verification test indicate that for low-temperature start-up, water is the most effective medium, followed by diluted HLLW and simulated HLLW. The recommended parameters are a rotational speed of 15 r/min and a flow rate of 40 L/h. For high-temperature start-up, simulated high level liquid waste with sucrose and diluted HLLW have similar effects, both of which are superior to water. The suggested parameters are a rotational speed of 30 r/min and a flow rate of 80 L/h. The feasibility of these start-up processes was confirmed through experimental validation. These findings provide valuable insights for optimizing the rotary calciner process and advancing the engineering application of the two-step cold crucible induction melting vitrification technique.