Abstract
Calcium has been known has a good decreasing in the leaching concentration of arsenic (As) and selenium (Se). Suppressing material, as the by-product of some industries which contains of high calcium, had been proven in decreasing of arsenic (As) leaching concentration from coal fly ash. This study aims to provide the useful reference in controlling As and Se leaching concentration into the environment through the effect of suppressing material addition. There are three suppressing materials that have been tested, that are: paper sludge ash (PS 3 and PS 4) and filter cake (FC). PS 3 shows the closest effect to Ca(OH)2 which is used as the standard, it shows almost 85-90% decreasing in As and Se leaching concentration based on ICP analysis. FC did not show an effect in As leaching concentration, but in the contrary with Se leaching concentration, it shows almost 60% decreasing. Calcium oxide has been known as the almost calcium compound which is containing in PS 3 and also known has the best decreasing on As and Se leaching concentration amongst the others calcium compound tested. Could be concluded that CaO is the most wanted calcium compound in controlling the As and Se leaching concentration into the environment.
