Preparation and resource utilization of sludge-based fire-preventive and extinguishing composite gel for coal mine

We prepared a sludge-based fire-preventive and extinguishing composite gel for coal mines using sludge, HPAM, water glass, and sodium bicarbonate as the main raw materials. Orthogonal test was used to analyze the effects of each component and its level on the performance of gel to determine the optimal ratio of gel and then tested its fire-preventive and extinguishing characteristics. Finally, the gelling mechanisms of the gel are discussed. The composite gel prepared at the optimal level showed that the gelling time can be maintained at about 55 s, the water retention can reach up to 58.6% in 12 h at 100 degrees C. The gel has a dense microstructure and uniform pores, and has the best inhibition rate of coal spontaneous combustion. As compared with other materials, the coal piled with gel did not reignite. TGA showed that the gel hinders oxidation and complete combustion of coal. The in-situ infrared analysis confirmed that the coal sample treated with gel has a low content of aliphatic hydrocarbon and hydroxyl group. Infrared spectroscopy analysis indicated that the sludge in the gel plays the role of filler. The organic-inorganic composite network structure formed by the sludge and the gel not only prevents the system from water loss and coal oxidation but also absorbs a large amount of sludge and realizes the resource utilization of sludge. Therefore, the preparation of composite gel reduces the secondary pollution of sludge and lowers the cost of the material, making it an economical and environmentally friendly fire-preventive and extinguishing material.

Automated summary

A sludge-based fire-preventive and extinguishing composite gel was prepared using sludge, HPAM, water glass, and sodium bicarbonate as the main raw materials. The effects of each component and its level on the gel's performance were analyzed using orthogonal test to determine the optimal ratio. The gel showed excellent fire-preventive and extinguishing characteristics and had a dense microstructure and uniform pores.