METHOD FOR TREATMENT OF FLY ASH

摘要

A method for a treatment of a fly ash, which comprises [1] a step (washing step) of washing a fly ash in a fluid having a pulp concentration of 5 to 100 g/L, to dissolve out a Ca component in the fly ash into water, and [2] a step of subjecting the slurry formed in the above washing step to a solid-liquid separation, to thereby recover the dissolved Ca component in a solution after washing and also recover a solid component as a washing residue. The blow of a CO2 gas into the above solution after washing forms CaCO3. On the other hand, the above washing residue has a low Ca content, which results in the by-production of a Pb-containing residue having a low content of gypsum through subjecting the washing residue to the leaching with sulfuric acid, and the Pb-containing residue is useful in Pb refining. Further, the solution after the separation of the Pb-containing residue can be used as a raw material for Zn refining.