Study on Methods for Synthesizing Biological Dust Suppressant by Microbial Fermentation and Performance Characterization

Mine dust control is the key to the safe, green and healthy development of the mining industry. In the process of mine production, it is often accompanied by a large amount of dust, which is not only easy to lead to dust explosion accidents, causing major casualties and affecting the safety production of enterprises, but also induce pneumoconiosis and seriously affect the physical and mental health of employees. Wetting dust reduction technologies are common measures in the mine production process. But due to the hydrophobicity of dust, the ability of pure water to wet the dust is limited. Adding dust suppressant to the water can improve the affinity of the solution. The commonly used dust suppressants are generally chemical suppressants, which have issues such as low surface activity and poor green environmental protection. Therefore, a new idea of using microbial fermentation technology was proposed to prepare biological dust suppressant (BDS). This paper utilizes theoretical knowledge from disciplines such as mine dust science, microbial fermentation, structural biology and interface physical chemistry. It combines theoretical analysis, experimental testing, physical simulation and field test to conduct research on the method and performance of biological dust suppressant synthesized by microbial fermentation. The main research findings and conclusions obtained are as follows:

The strains for synthesizing BDS were screened and the growth and metabolism of the strains were investigated. When sucrose is used as the carbon source and soybean meal as the nitrogen source, the growth duration of the engineered strain can be set to 9 hours. The concentration of the engineered strain can reach a high level, with the growth rate doubling compared to the pre-screening strain. The synthesis method of BDS was studied and the molecular structure characteristics of the product were preliminarily revealed. The optimal conditions for BDS production were found to be a temperature of 37.56°C, pH of 7.99, agitation speed of 220 rpm, inoculum size of 2.17% and liquid volume of 59.89 ml. It was also determined that BDS is a non-crystalline substance containing long-chain and cyclic heptapeptide ester structures. The interfacial activity, wettability and interfacial rheological properties of BDS were characterized. The results indicate that the critical micelle concentration of the biological dust suppressant is 30 mg/L and the surface tension of water is 27 mN/m. BDS can maintain stable interfacial activity in different solution environments (temperature below 70°C, pH ranging from 5 to 9, salt concentration below 15%). Additionally, BDS exhibits higher viscoelastic modulus than AEO, indicating better rheological performance. The drainage law of dust suppression foam and the foaming performance of BDS by microbial fermentation were characterized. When the concentration of BDS is 0.15‰ and the polymer concentration is 0.3‰, the foaming ability, foam half-life and liquid half-life reach their optimum.

This research lays the theoretical foundation for the development of high-performance, environmentally friendly and non-toxic mining dust suppression materials using microbial fermentation technology. It plays a proactive role in promoting the application of green and efficient dust control technologies in mining dust control.