Disclosed herein is a method of heat-treating particulate material, such as kaolin. The method comprises providing a feed mixture comprising a particulate material, such as hydrous kaolin, wherein at least a portion of the particulate feed is coated with an additive/liquid fuel mixture comprising at least one additive dispersed in liquid fuel. The method further comprises heating the particulate feed to heat treat, e.g., calcine, the particulate feed and burn the liquid fuel to form a heat-treated product. The liquid fuel coating can act as a secondary, indirect heat source for heat treating.