Study On Dust Distribution Law And Prevention Technology At Ore Pass Discharge Port Of Metal Mine

Dust pollution in metal mines is not conducive to the health of workers,and at the same time has a great impact on the service life and accuracy of on-site equipment.Among them,dust pollution caused by the transfer of ore in the pass accounts for the main part.Aiming at the unloading port of Nanjing Meishan Iron Mine,this paper uses a combination of theoretical analysis,numerical simulation and actual measurement to study the generation of impinging airflow and the diffusion of dust when unloading from the chute,and analyze its influencing factors..At the same time,the dust reduction measures applicable to the chute are proposed and implemented on site.Through theoretical analysis,the generation mechanism and influencing factors of dust during the unloading of the chute are obtained.At the same time,the basic formula for the airflow generated in the high chute is derived.The influencing factors of the dust concentration are obtained as follows: discharge flow,discharge height,discharge amount and The diameter of the discharge port.Aiming at the unloading port of Nanjing Meishan Iron Mine,based on the gas-solid two-phase flow theory,using the DDPM model and using FLUENT numerical simulation software,the characteristics and laws of the dust concentration distribution at the unloading port under different working conditions are studied,and the key influence of the dust concentration is reached.Factors and comparative analysis with on-site measured data,the results of the simulation are in accordance with the data measured in the field,which verifies the precision of the simulation.According to the study,under the initial working conditions,the dust concentration at the unloading port first rises rapidly,reaches the peak,and then gradually decreases.In about 10 s,the dust particle concentration reaches the maximum,and then eventually stabilizes as the dust continues to settle;The unloading flow is proportional,and at the same time,the greater the unloading flow,the longer the duration of the peak dust concentration.The dust concentration distribution during unloading is greatly affected by the wind flow.During the unloading process,induced airflow and impinging airflow are generated in the chute,and the change of induced wind speed is basically consistent with the change of dust concentration.The paper further studied the characteristics of atomization and agglomeration and found that air-water spray is the most convenient and effective method to control the ore unloading dust from the chute.A relatively suitable spray system was established,and the dust control for the unloading mouth of the chute of Nanjing Meishan Iron Mine was proposed.This method have positive effect on reducing the dust and improving the working condition of the stope.