Study on preparation of ADP composite colloid by the effective component from activated fly ash and its fire prevention mechanism

The application of industrial solid waste fly ash (FA) to fire prevention material is an effective way to realize its large-scale resource utilization. How to improve the performance and application range of FA type fire-fighting materials has become an engineering roadblock. In this study, the activation technology was introduced to extract effective component from FA, and the Ash-Diatomite-Polyacrylamide (ADP) colloid with double-aggregate was prepared mainly by activated modified FA. The ICP data of active substance in liquid phase indicates that acid-base combined excitation can release a large number of active components through chemical activation of FA. The physical properties of ADP colloids were tested by measuring the colloid permeability, water retention, and thermal stability. Meanwhile, the chemical flame retardancy of colloids was also determined by the inhibition experiment and thermogravimetric analysis. Experiments results indicate that Al3+ and Fe3+ released by excitation can be acted as cross-linking agents in the formation of colloids, and Ca2+ and Mg2+ released can be used as inhibitors for coal spontaneous combustion. ADP colloid can still inhibit the release of CO and CO2 at 220 °C with higher inhibition rates. The values of activation energy prove that ADP composite colloid can effectively increase the energy required by the interaction between coal and oxygen. Moreover, the multi-component cooperative fire-prevention mechanism of ADP was explored based on the effective composition, gelling mechanism, and fire-retarding action sequence of composite colloid.