Abstract
In this paper, the fly ash cyclic gradient washing dechlorination process is systematically studied through experiments, and the effects of process parameters such as liquid-solid ratio, the number of leaching, and process pulping on the dechlorination effect of fly ash are investigated and analyzed with the currently operating three-stage counter-current washing dechlorination process. The experimental results indicate that with the liquid-solid ratio of 3:1, the number of leaching of 4, and the primary process pulping, the chlorine content of washing fly ash is reduced to 0.5-0.6%. The Baume degree in the washing filtrate is increased to 11-12 °Bé, the total amount is reduced by about 15%, and the average turbidity value is ≤5NTU. Meanwhile, the moisture content of the washing fly ash is reduced to 28-30%. By comparing with the actual construction project, it is found that under a disposal capacity of 100 t/d, the cyclic gradient washing dechlorination process can reduce the installed power by 30.3%, the floor space by 32.9%, the treatment volume of washing filtrate by 11.1%, and the drying load by 27.9% compared to the traditional three-stage counter-current washing and dechlorination process.