| 摘要 |
PROBLEM TO BE SOLVED: To provide a pre-processing method for recovery of heavy metal from fly ash wherein later separation of heavy metal is facilitated by relatively increasing a ratio of heavy metal in fly ash in product gas in a thermal decomposition melting furnace or in combustion gas in a refuse incinerator. SOLUTION: In a pre-processing method for recovery of heavy metal from fly ash, heavy metal concentration in the fly ash contained in combustion gas is relatively increased, and successively the fly ash is recovered as fly ash of high concentration of heavy metal by a dust collector by reducing the weight of the fly ash in a combustion process where high concentration oxygen or desirably oxygen rich air of the oxygen concentration of 25% or more is supplied to product gas to combust a remaining combustible substance such as char contained in the product gas at high temperature. Thereafter, the operation is advanced to a later separation process for heavy metal. |
