Method for producing electromagnetic wave absorbing sheet, method for classifying powder, and electromagnetic wave absorbing sheet

摘要

An object of the present invention is to provide a method for producing an electromagnetic wave absorbing sheet with properties thereof further improved. A treated powder P0 pulverized and flaked in a pulverizing step is placed in a centrifugal gas-flow classifier 50. The treated powder is classified into a flaky soft magnetic metal powder P1 and a non-flaky powder P2 on the basis of the difference between the centrifugal force and the drag acting on each of these powders in a gas flow circling in a chamber 51. The non-flaky powder P2 is eliminated and the flaky soft magnetic metal powder P1 is used to form an electromagnetic wave absorbing sheet, the performances of the electromagnetic wave absorbing sheet being thereby improved. The classified non-flaky powder P2 is preferably recycled as the raw material powder used in the pulverizing step.