| 摘要 |
PROBLEM TO BE SOLVED: To produce white molten slag from the incineration ash of sewage sludge. SOLUTION: The incineration ash of sewage sludge from a storage tank 2A and a reducing agent from a storage tank 2B are melted in a melting furnace 5. The slag component contg. SiO2, CaO and Al2O3 among the contents of the melt L is not reduced, the metal-oxide colored component contg. at least iron oxide is reduced by the agent, and the low-b.p. metallic component contg. lead and zinc in the melt L is vaporized off. Further, the high-b.p. metallic component contg. iron, copper, nickel, chromium and their alloy is settled to separate the melt L into a slag-component layer L1 and a high-b.p. metallic- component layer L2, then the melt L is introduced into cooling water W and quenched, hence the solidified high-b.p. metallic component MS is settled on the water bottom, the slag component is foamed and solidified into a molten slag SS which is floated up on the water surface, and the floated molten slag is discharged.
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