The intimate contact of two or more components and/or phases used to achieve a desired product quality. Mixing is also used to promote mass transfer or enhance the rate of a chemical reaction. Blending is a type of mixing that involves particulates or powders. Mixing can involve dispersing one phase through another such as sparging gases through liquids, or the use of rotating agitators, impellors, and propellers. Fluidized beds provide excellent mixing to enhance both heat and mass transfer in which a fluid, such as a gas, is driven up through a bed of particles, such as a catalyst.