The efficacy of pH-dependent leaching tests to provide a reasonable estimate of post-carbonation leaching

Highlights: • pH-dependent leaching applicability for carbonated waste materials was explored. • Samples underwent accelerated carbonation and were leached with EPA Method 1313. • XRD was performed to identify differences in mineralogy between materials. • pH-dependent leaching tests were partially applicable for carbonated waste. • Implications for pH-dependent leaching efficacy were explored. -- Abstract: pH is a vital factor related to the heavy metal leaching from wastes. Over time, waste materials may be naturally weathered in the presence of water and carbon dioxide, reducing their pH and altering their mineralogy. Here we evaluate whether conducting a pH-dependent leaching test on wastes expected to carbonate sufficiently reflects the leaching of these wastes upon carbonation. Certain elements, such as Al and Sb, exhibited different leaching trends for carbonated and un-carbonated samples of two different waste materials. XRD results observed different mineral phases as a result of carbonation in incineration bottom ash. The application of pH-dependent leaching tests on fresh waste samples (at neutral pH values) were found to potentially mischaracterize leaching from carbonated waste samples at similar pH values for some elements and waste materials.