Chromium and Fluorine Insolubilize Agents and a Treatment Method on Biomass Incinerated Ash

Biomass incinerated ash sometimes contains hazardous substances such as hexavalent chromium and fluorine, which poses an obstacle to recycling. In order to remove or insolubilize these harmful substances, aqueous solution of Iron (II) sulfate and mixed solution of sulfuric acid and calcium hydrogen phosphate were added to the incineration ash. In order to thoroughly detoxify the ash, we devised a method in which an excessive amount of treatment liquid is added to the ash, and the surplus water generated is used for monitoring or reused as treatment water. This made it possible to reduce the harmful substances in the ash to below the environmental standard value in a short time.