POWDER CLEANING METHOD

To provide a powder cleaning method that enables powders to be satisfactorily filtered from slurry including the powders and solvents and enables the filtered powders to be satisfactorily cleaned.SOLUTION: A powder cleaning method with use of a filter is provided, the filter comprises a vessel which has an upper portion and a lower portion separated from each other by a porous layer, and has a liquid supply port at the upper portion and a liquid outlet at the lower portion. The method has: a step (1) (filtering step) in which slurry including a good solvent for powder and liquid and a poor solvent for powder is supplied to the upper portion of the filter from the liquid supply port, and the slurry is filtered while pressure of the upper portion of the filter is so maintained as to be higher than pressure of the lower portion, as a result, a cake layer is formed; and a step (2) (cleaning step) after the step (1), in which cleaning liquid including the poor solvent for powder is supplied to the upper portion of the filter from the liquid supply port to thereby clean the cake layer while the pressure of the upper portion of the filter is so maintained as to be the pressure or more of the upper portion upon completion of the filtering step. Both of the filtering step (1) and the cleaning step (2) are performed while maintaining the state that whole surface of an upper portion of the cake layer is always coated with the liquid.SELECTED DRAWING: None 【課題】本発明は、粉体及び溶媒を含むスラリーから粉体を良好にろ過及び洗浄できる、粉体の洗浄方法を提供する。【解決手段】ろ過器を用いた粉体の洗浄方法であって、ろ過器が、上部と下部とが多孔質層で隔てられた容器からなり、容器の上部に液供給口を、下部に液抜出口を有しており、（１）粉体、粉体に対する良溶媒、及び粉体に対する貧溶媒を含むスラリーを、液供給口からろ過器の上部に供給し、ろ過器の上部の圧力を下部の圧力より高く維持した状態で濾過してケーキ層を形成する工程（ろ過工程）、並びに（２）その後、ろ過器の上部の圧力を、ろ過工程完了時の上部の圧力以上に維持した状態で、粉体に対する貧溶媒を含む洗浄液を液供給口からろ過器の上部に供給し、ケーキ層を洗浄する工程（洗浄工程）を有し、ろ過工程（１）及び洗浄工程（２）がいずれも、常にケーキ層の上部表面全体が液体で被覆された状態を維持して実施される、洗浄方法。【選択図】なし