Preparation of superabsorbent lignin-based composite inhibitor and research on its prevention and control characteristics of coal spontaneous combustion

With the potential safety hazard of coal spontaneous combustion becomes more and more serious, in order to solve the problems of low water absorption rate and high cost of hydrogel inhibitor, in this study, a superabsorbent lignin-based composite inhibitor (SAP + SLS + Ben) was prepared. The water absorption/retention rate, micromorphology, inhibition capacity, air-leakage blocking efficiency and fire-extinguishing performance of SAP + SLS + Ben were studied. Results have revealed that: SAP + SLS + Ben had excellent water absorption/retention capacity; SEM images revealed that sodium lignosulfonate (SLS) and bentonite (Ben) provided the structural basis for the high water absorption/retention of SAP + SLS + Ben; Compared with SAP, SAP + SLS + Ben could effectively inhibit the oxidation of reactive functional groups in coal, and the amount of CO released from coal treated with SAP + SLS + Ben was significantly reduced at high temperature; The air-leakage blocking and fire-extinguishing experiments showed that SAP + SLS + Ben had good filling and blocking performance, and could effectively reduce the temperature of coal spontaneous combustion and prevent the re-ignition of coal. Hence, SAP + SLS + Ben had ideal physical and chemical inhibition properties, which could effectively prevent coal spontaneous combustion in goaf.