Red Mud—Its Properties and Application in Geotechnical
3.5 pH. pH denotes the Potential of hydrogen which is a scale to measure the acidity and basicity of the material. From various studies it is observed that pH of Red Mud is generally higher than other waste materials like fly ash whose pH is around 5.5 but on the other side it is comparable to steel slag whose pH lies in the range of 10.6–12.9 [].