Experimental study on solidification and leaching toxicity test of arsenic-containing fly ashes

The article investigated the mehhod for disposing the arsenic -containing fly ahs by cement solidification . They also studied leaching characteristic of arsenic in the solidification of cement under diferent pH values , liquid/solid radios and extraction time. The results showed that pH was a major controling factor in arsenic leachability. The arsenic exhibited a marked increase in leachability at low (pH2) and sometimes high (pH11) values, while relatively low leachability of arsenic were observed at neutral conditions (5pH11). Total extractable arsenic concentration increased as the liquid-to-solid ratio, but concentration of arsenic in leachate decreased because lower mass of waste in the leaching solution. Arsenic mass concentrations extracted by acetic acid solution were higher and more stable than those extracted by de-ionized solution.