2-21　Development of technology to prevent elution of regulated elements from coal ash utilizing waste partⅡ

Abstract

Coal ash production is increasing year by year, but its application is very limited at present. Therefore, new applications of coal ash for its mass consumption is are needed. However, the use of coal ash requires both high safety and cost efficiency. We have reported at the last year's Coal Science Symposium that, the amount of elution of harmful elements from coal ash can be reduced below the environmental standard value by calcining a mixture of coal ash and two types of waste. In this research, we also found that phosphorus and calcium included in waste played an important role in reducing the elution of harmful elements. Based on this result, not only we can utilize a wide variety of wastes for mixing with coal ash, but we also can simultaneously insolubilize multiple wastes other than coal ash. Moreover, we found that the granulated material obtained by calcining waste could be utilize as soil improving material and promoted the growth of plants without increasing the concentration of harmful elements in the plants. In this lecture, we will report on the current state of technological development to prevent the elution of regulatory elements from coal ash using waste.