Mixing Effects on Coal Processing Waste Treatment

Abstract

AS a consequence of new coal mining practices, coal preparation plants have been inundated with increased loads of coal and clay particles in their wastewater. Traditionally, the industry has employed primary sedimentation for the treatment of these sediment‐laden waters. This study examined the possible use of commercial coagulants for the treatment of these wastewaters, with specific emphasis being placed on the impact of mixing conditions on observed solids removal. Aluminum sulfate and cationic polymers were utilized in research studies under varying conditions of mixing intensity and time. The results showed that efficient coagulation was accomplished under a variety of mixing conditions, with poor solids removal noted only when the coagulated suspensions were exposed to excessive shear. Particle size distribution analyses were utilized extensively in the interpretation of experimental results and the formulation of project conclusions.