Kinetics of dehydroxylation of kaolin in presence of oil field effluent treatment plant sludge

Oil field effluent treatment plant (ETP) sludge contains high amounts of hydrocarbon and its disposal by land filling is a problem. Various methods to utilize the sludge and circumvent the disposal problem have been suggested. The high calorific value of the sludge may be used in calcination of clay and manufacture of ceramic materials. This communication reports the kinetics of dehydroxylation of a kaolin clay in presence of ETP sludge. Nonisothermal methods are applied to obtain the thermal curves. Nine solid-state mechanisms are applied for analysing the data obtained in the temperature range of 450–750 °C. Random nucleation is the major process of decomposition in both the clay and clay–sludge mixture at the lower temperature range (450–600 °C). At higher temperatures (600–750 °C), the thermal decomposition of the sludge follows a three-dimensional diffusion process and occurs at the phase boundary with spherical symmetry. The thermal decomposition of the clay–sludge mixture, in the temperature range of 600–750 °C, occurs at the phase boundary with cylindrical symmetry. The kinetic parameters follow the kinetic compensation effect.