The invention relates to a preparation method of multi-phase gel foam for controlling the
spontaneous combustion of
coal. The multi-phase gel foam with multiple components of medium is made by adding a slight amount of thickener into the
fly ash or the yellow mud
slurry to form thickening mud with certain
viscosity, adding certain amount of cross-linking agent and
foaming agent into the thickening mud, and introducing
nitrogen to carry out the physical and mechanical foaming. The bubble wall of the multi-phase gel foam has high
viscosity and good elasticity, the
fly ash or yellow mud adhere to the bubble wall, and the bubble is internally covered with
nitrogen. The multi-phase gel foam is delivered to the mined-out area through the grouting pipeline of the mine, evenly covers the float
coal in the mined-out area, and blocks the fractures of the
coal body. The method can effectively hinder the
oxygen absorption for goal and prevent the oxidization of the coal. The preparation method is simple, and the prepared multi-phase gel foam has low cost and significant effects on
fire prevention and extinguishing; the preparation method does not only have the advantages of mud injection,
nitrogen injection, two-phase foam injection, gel injection and composite gel injection on
fire prevention and extinguishing, and also overcomes the deficiency, which has wide practicality.