Experimental study on the selection of coal-to-oil gasification ash slag gel gelling agent

The gasification ash slag (GAS) is a solid waste that is difficult to degrade and causes serious environmental pollution. In this study, a new type of mine fire prevention and extinguishing gel material was prepared from gasified ash as a base material for spontaneous combustion control of coal in the mining airspace. To better enhance the gel fire prevention process pipeline conveying efficiency, and fire extinguishing performance, the selection of seven gelling agent formulation gasification slag gel, through the thermal stability, water retention, and rheological experiments preferred the best performance of the gelling agent. Thermal stability experiments showed that the thermal decomposition of the gel was divided into three stages: water loss, gel decomposition, and secondary decomposition of decomposition products, and the analysis of the initial decomposition temperature and mass loss rate yielded the best thermal stability of CB-GAS; Water retention experiments show that XG-GAS still retains 72.33 % of water at the 11 h in high-temperature environment, which is the best water retention performance; The rheological experiments showed that the viscosity of the gel decreased continuously with the increase of shear stress, and the analysis of the parameters yielded the best rheological properties of CBGAS. Combining the four performance indicators, the hierarchical analysis method was used to calculate the influence weight value of the indicators and carry out comprehensive scoring, which resulted in the best performance of the gasification ash fireproofing gel prepared with the optimal gelling agent CB, followed in order by XG, CMC, HPG, MC, SA, and HPMC. This study provides an important reference for gel grouting fireproofing.