Additive injection device for sand mixer

The utility model discloses an additive injection device for a sand mixer. The feeding device comprises a sand mixer sealing cover and a folding type feeding hopper, internal thread connecting columnsare arranged on the left side and the right side of the middle of the upper end of the sand mixer sealing cover. A threaded feeding pipe is connected to the inner positions of the upper portions of the two inner threaded connecting columns in a sleeved mode. Double-injection device, therefore, after the two folding type feeding hoppers and the two threaded feeding pipes are connected with each other, materials can be fed; external thread connecting bodies in the two threaded feeding pipes are rotationally fixed with the two internal thread connecting columns, so that the two threaded feedingpipes can be connected; therefore, the casting sand, the binding agent and the water enter the sand mixer through the two folding type feeding hoppers and the two threaded feeding pipes; when the sandmixer is used, different a