A method of fermentation synthesis of mine biological dust suppressant with matrix homogenization
Abstract
Dust is easily generated in all parts of the mining process, which can cause dust explosions and lead to occupational pneumoconiosis in workers. Therefore, dust reduction is crucial in mining operations and plays an important role in protecting the environment and worker health. While traditional chemical dust suppressants provide short-term effectiveness, they pose considerable challenges. These include poor resistance to natural degradation, low environmental performance, and the risk of secondary pollution of soil and water sources, creating a growing demand for sustainable alternatives. To address these challenges, the authors proposed the idea of using microbial fermentation to synthesize biological dust suppressants.
To enhance the scalability and efficiency of microbial fermentation dust suppressant (MFDS) production, this study used a self-developed experimental device for fermentation and synthesis of biological dust suppressants. Six straight-blade disc paddles (6S-DR), six semicircular-blade disc paddles (6S-SDR) and four inclined straight-blade paddles (4-IR) were selected to design eight mixing combinations. Numerical simulations were performed to analyze key parameters, such as the matrix flow field velocity, turbulent kinetic energy, gas holdup, and stirring power. In addition, experimental tests were conducted to validate gas holdup and MFDS yield under different conditions. Furthermore, MFDS solutions of three purities, acid precipitation, single-stage ultrafiltration, and two-stage ultrafiltration, were characterized using liquid chromatography-mass spectrometry (LC-MS). MFDS was conducted using an LC-MS system. Tests for interfacial performance and wettability of MFDS were also performed to assess its dust suppression capabilities at different purity levels.
The results indicated that the stirring combination, using four oblique straight paddles, formed an obvious liquid circulation area. Adding an extra layer of paddles further expanded this area, enhancing heat and mass transfer. Stirring combination H demonstrated smaller liquid surface fluctuations and a more uniform distribution range of turbulent kinetic energy. These features increased dissolved oxygen levels and improved gas-liquid mass transfer, fostering microorganism growth. Consequently, stirring combination H achieved better substrate homogenization and delivered better fermentation performance under identical conditions.Interfacial performance tests revealed that when two-stage ultrafiltration was used, the critical micellar concentration of the bioreactor solution decreased to 22.65 mg/L. The higher the purity of the MFDS solution was, the smaller the critical micelle concentration of MFDS, and the viscoelastic modulus stabilized with increasing concentration. The ultrafiltration technique had a greater effect on the MFDS viscoelastic modulus, but the number of ultrafiltration cycles had a smaller effect on the viscoelastic modulus. The viscoelastic modulus stabilized as the concentration increased. Moreover, wettability tests indicated that the two-stage ultrafiltration purification improved dust suppression efficiency, achieving the shortest dust settling time of 67 s and remarkable wettability performance. Considering the results of the surface interface performance and wetting performance tests, the dust suppression performance of the two-stage ultrafiltration MFDS was superior.
This study investigated large-scale synthesis methods for biodust suppressants, focusing on matrix homogenization to increase production efficiency and scalability. This approach addresses key shortcomings of traditional chemical dust suppressants, including poor degradability, low surface activity, and environmental harm. By overcoming these issues, this study offers a meaningful solution to reduce dust pollution, protect the environment, and improve the occupational health of miners. Meanwhile, this study provides valuable theoretical guidance for the efficient development of green and environmentally friendly biological dust suppressants.
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