Investigation of Heavy Metal Solidify Mechanism of Fly Ash-Contaminated Soil-Based Ceramsites
Fly ash synergized with heavy metal contaminated soil were used to prepare ceramsites,and the effect of sintering process on the mechanical properties of ceramic grains and the migration and transformation of heavy metals was investigated.The results showed that the moderate addition of water-washed fly ash reduced the melting point of ceramsites and promoted the formation of ceramsites into liquid phase more easily.Both the increase in sintering temperature and sintering time resulted in an increase in the liquid phase inside the ceramsites,an increase in bulk density and a decrease in water absorption.The best sintering process was preferred:the ceramsites prepared by preheating at 400℃for 10 min and sintering at 1 150℃for 20 min had a 1 h water absorption rate of 8.20%and a bulk density of 965 kg/m3;the leaching of heavy metals was standardized,and the residual fraction accounted for the highest percentage.The glassy phase produced during sintering encapsulated heavy metals and the reaction of heavy metals with Si-Al minerals to form stable silica-aluminate worked together to solidify heavy metals in the ceramsites.
NETL
NSTL
万方数据
