Agitation is a means mixing of phases can be accomplished and by which mass and heat transfer can be enhanced between phases or with external surfaces. the process of mixing is concerned with combinations of phases. Gases with gases. Gases into liquids such as dispersion. Gases with Granular solids such as fluidization, pneumatic conveying, drying. Liquids into gases such as spraying and atomization. Liquids with liquids such as dissolution, emulsification, dispersion. Liquids with granular solids such as suspension. Pastes with each other and with solids. Solids with solids such as mixing of powders. Generally used this type of impeller for Agitation: Sawtooth, Hydrofoil, Propeller, Anchor Blade, Disk turbine, curved Blade turbine, Pitch Blade Turbine, Straight blade Turbine