Rheological characteristics of foamed gel for mine fire control

SUMMARY Foamed gel as a new type of fire extinguishing material is used to prevent the spontaneous combustion of coal. In order to make a comprehensive study on rheological characteristics of foamed gel for mine fire control, by using type NDJ-5s digital viscometer, the factors such as mass concentration of the mixture mixed by thickener and crosslinker, foaming multiple, added salts (NaCl, CaCl2, AlCl3), pH value and temperature having influences on the rheological properties of foamed gel have been investigated in this paper. It can be found that foamed gel shows the characteristic of non-Newtonian fluids and has shear-thinning properties. With increasing of mass concentration of the mixture, the thixotropy response becomes more significant. When the foaming multiple reaches 20, the apparent viscosity gets the maximum value. The obvious viscosity characteristic of ‘polyelectrolyte solution’ is observed in aqueous salt solutions when added salts are put into the solution. Under different conditions of pH values, foamed gel has higher sensitivity to acid than alkaline. Zero shear viscosity, depending on temperature, decreases with the temperature increasing. Meanwhile, the fire performances of foamed gel are studied experimentally and theoretically. Copyright © 2014 John Wiley & Sons, Ltd.