Method for dredging soft blockage of long-distance iron ore concentrate pipeline

The invention relates to a method for dredging soft blockage of a long-distance iron ore concentrate pipeline, which can effectively shorten the dredging time and reduce the dredging cost. The adopted technical scheme is that a water channel in the pipeline is firstly dredged, and then retained slurry in the pipeline is dredged, wherein the concrete method for dredging the water channel in the pipeline comprises the following steps of: switching a booster pump station to a water delivery mode, starting to deliver water into the pipeline with minimum flow, gradually increasing the flow, monitoring the outlet pressure of the booster pump station and the pressure in the pipeline, stabilizing outputting flow by the booster pump station when the pressure is the maximum in a normal range until the pressure in the pipeline drops to a value twice that of static pressure, increasing the flow and gradually dredging the water channel; and the concrete method for dredging the retained slurry in the pipeline comprises the