Simulation on the Effect of Supercritical Carbon on Cu Ions Leaching Behavior in Cement Solidification Body

Residue of city garbage disposal such as fly ash contains lots of harmful substances such as heavy metals, which need to be treated before landfill or recycling utilization. The modification effect of supercritical accelerated carbonation process on cement solidification body (CSB), make up for the deficiency of large porosity. To study the effect of supercritical carbonation on leaching behavior of heavy metal ions in the CSB, the numerical simulations were performed on the leaching rate and leaching distribution pattern of Cu ion. The results showed that supercritical carbonation reduced the leaching rate of Cu ion in the CSB, which was more obvious when leaching time was shorter than 14 days. The start time was brought forward on stable cumulative leaching concentration of Cu ions, due to the Carbonization process. Furthermore, it was found that the distribution of leaching rate on the CSB section was alternative positive and negative. The supercritical carbonation increased the scope of the outermost positive region layer, and changed the plane distribution of the Cu leaching rate in the CSB, which made contribution to the inhibition of heavy metal ion leaching.