Comparative leaching experiments for trace elements in raw coal, laboratory ash, fly ash and bottom ash

Samples of raw coal, fly ash and bottom ash have been collected from a Chin ese power plant together with laboratory ash obtained by ashing of the coal under 850 degrees C. Comparative-leaching experiments were carried out on each fraction under various pH conditions. A mathematical model for leachin g of trace elements has been developed and leaching intensity (I,) has been calculated for each element. The results show that pH of the solution, lea ching time, and particularly, properties and occurrence of the elements, ha ve a strong influence on leaching behavior. (C) 1999 Elsevier Science B.V. All rights reserved.