Method for cleaning excess material of concrete mixer truck back to factory

The invention discloses a method for cleaning excess material of a concrete mixer truck back to a factory. The method comprises the following steps that (1), CO2 gas is introducing into a reaction kettle filled with water, wherein the internal pressure in the reaction kettle is controlled to be 1-5 Mpa, and the pressure is maintained to prepare a cleaning liquid; and (2), the cleaning liquid is used for cleaning the tank of the concrete mixer truck which returns the factory, the excess material is cleaned, specifically, the cleaning liquid can be sprayed into the tank of the concrete mixer truck which returns the factory through a high-pressure spray pipe. According to the method, a weak acid solution formed by CO2 gas is adopted to clean the excess material in the mixer truck, the excessmaterial in the tank can be rapidly cleaned, and the cleaning time and water consumption are greatly reduced; in addition, cleaned material obtained by the cleaning method can be directly added into afinished concrete mixer t