Abstract: A method is provided for treating used potassium chloride (KCl) drilling mud for disposal. The process comprises feeding the mud into one end of a rotary tube, advancing the mud through the rotating tube and heating the mud by cascading action using lifters, to expose it to a hot gas stream, thereby partially drying the mud to lumps, further modifying the lumps by contacting them with a burner flame to form clinker pellets, and finally contacting the clinker pellets with a second flame to complete the drying process, producing dried clinker pellets containing the majority of the KCl in the mud, the pellets having a structure that resists the leaching action of water. The pellets further lend themselves to being evenly distributed over fields, so that unwanted excessive concentrations of KCl can be avoided.