The utility model discloses a poly aluminium chloride chemicals feeder for coal separating plant belongs to coal separating plant coal slime water treatment medicine machine. The chemicals feeder includes the chemicals feeder box, adds medicine mouth and comb board, overflow passage, adding pipe and flow control valve, and chemicals feeder box upper portion sets up water intake pipe and valve, level gauge, and the box lower part sets up blast air pipeline and valve, equipment base, and the box outside is equipped with the cat ladder. Add poly aluminium chloride in medicine mouth comb board adds the chemicals feeder box of filling with water by chemicals feeder box upper portion, the medicament mixes, dissolves under the wind -force mixing effect of below, after half a hour, opens adding pipe flow control valve control with the dose. Its simple structure, convenient operation, excellent in use effect.