Experimental study on flow characteristics of gasification ash slag grouting

This paper analyzes the elements and chemical components contained in the gasification ash through elemental analysis and X-ray fluorescence spectroscopy, and proposes that the gasification ash should be poured into underground goaf as grouting fire prevention material. In order to solve the problem that the gasification ash slurry is easy to block the pipeline during the long-distance transportation process, the polymer surfactant carboxymethyl cellulose（ＣＭＣ） is used as the suspending agent. Water separation rate and fluidity of the slurry are tested by suspension and flow experiments under different water-cement ratios and suspending agent additions. The results show that the gasification ash contains a variety of metal elements and non-metal elements. These elements mainly exist in the form of oxides. The oxides with higher content are SiO2, Fe2O3, CaO and Al2O3. When the amount of gasification ash and CMC increased, the water extraction rate and fluidity of grout decreased gradually. Through the suspension test, when the slurry water-cement ratio is 1∶0.2, the CMC addition amount should be greater than 1.25%. When the water-cement ratio is 1∶0.4, 1∶0.6 or 1∶0.8, the CMC addition amount should be greater than 0.5%. If the water-cement ratio is 1∶1, the addition amount of CMC should be greater than 0.25%. If the water-cement ratio exceeds 1∶1, the slurry appears as paste, which does not meet the requirements of grouting.