NOVELTY - The filter assembly comprises a filter container having ferric solution, lithium solution and a product, where the filter container is provided with a filter. A sidewall of the filter is provided with multiple nozzles. The product is passed into the filter for generating supercritical water through supercritical reaction using inflowing power. Powder in the product is filtered in slurry state. The filter is rotatably arranged in a ceiling surface of the filter container in fixed axis to the idle state.    USE - The filter assembly is useful for manufacturing cathode active material (claimed), which is useful in lithium ion secondary battery, nickel-cadmium cell or nickel-metal hydride battery for hybrid electric vehicle.    ADVANTAGE - The filter assembly is cost-effective, and has improved filtering efficiency.    DETAILED DESCRIPTION - The filter assembly comprises a filter container having ferric solution, lithium solution and a product, where the filter container is provided with a filter. A sidewall of the filter is provided with multiple nozzles. The product is passed into filter for generating supercritical water through supercritical reaction using inflowing power. Powder in the product is filtered in slurry state. The filter is rotatably arranged in a ceiling surface of the filter container in fixed axis to the idle state. A rotation ball is formed at the fixed axis. A connecting tube is pivotally connected in the rotation ball and the filter. The filter is hollow cylindrical in shape, and extended inside the filter container along upper and lower direction. A center position of the nozzle is made eccentric by rotation of filter. A wire is extended perpendicular to the sidewall of the filter container and to an edge of filter. The nozzles are arranged in multiple rows along the vertical direction. An extension part in a flow cross section of the product is installed in the side of the filter container. An INDEPENDENT CLAIM is included for a manufacturing device including the filter assembly.