Study On Prevention And Control Of Dust From Tailings Pond

Tailings are solid waste produced after ore separation.At present,there are more than 10,000 tailings ponds all over China,and a large number of tailings are piled into the tailings ponds every year.Tailings reservoir has a great impact on the ecological environment of the mine,especially the dust from the tailings reservoir has caused serious pollution to the surrounding environment of the reservoir area.For this reason,CCTV has exposed the dust pollution problem from the tailings pond of Shanxi Branch of Aluminum Corporation of China.Therefore,how to effectively prevent and control the dust from tailings pond and builds environment-friendly mines has become one of the keys and hot topics for the sustainable development of mining industry.In this paper,a comprehensive method,combining theoretical analysis,laboratory test and numerical simulation,is used to conduct an in-depth study on tailings pond dust and its prevention and control methods.The main research work and achievements are as follows:(1)The dust suppressant was screened through indoor tests.The dust suppression effect of three kinds of halides(sodium chloride,magnesium chloride,calcium chloride)and three kinds of polymer materials(calcium lignosulfonate,polyvinyl alcohol,polyacrylamide)on copper tailings was studied.Furthermore,three important factors including solution concentration,spraying amount and wind speed was considered.And the wind erosion loss and the anti destruction performance of crusts were taken as evaluation indexes.The results show that calcium chloride and polyacrylamide can inhibit the dust of copper tailings.The durability,penetration depth test and liquid-plastic limit test of the selected dust suppressant were carried out to explore the environmental adaptability of the dust suppressant and its influence on the p Hysical and mechanical properties of copper tailings.(2)The preparation method of dust suppressant was optimized by response surface method.Under the condition of the respective concentrations determined previously to remain unchanged,the factors of spraying amount,spraying sequence,mixing ratio and storage time was considered.The wind erosion loss and crust penetration resistance were still taken as the response value.The test results are basically consistent with the theoretical prediction values.Moreover,the optimized dust suppressant is obtained.(3)The general applicability of the dust suppressant was studied through indoor experiments.Calcium chloride,polyacrylamide and optimized dust suppressant solution were sprayed on the p Hosp Horus tailings respectively,and compared with spraying water.The results shown that the anti-wind erosion performance and the anti-destructive performance of the surface of the p Hosp Horus tailings were improved after spraying the dust suppressant,but the dust-proof effect was not as obvious as that of the copper tailings.The reason is that the particles of p Hosp Hate tailings are extremely fine.For this kind of tailings,as long as the water is sprayed in time to ensure the integrity of the surface crust,it can have a good dust suppression effect.(4)The XRD technology and SEM electron microscope test were used to reveal the solidification mechanism of dust suppressant on tailings particles.The solidification effect of calcium chloride on the tailings particles is mainly to reduce the thickness of the combined water film between the tailings particles,and play the role of filling and connecting the tailings particles.Polyacrylamide with a long-chain structure,have solidification effects on tailings particles,such as linking,winding,film-forming effects and so on.(5)The plant dust suppression method was applied to the research on the prevention and control of the dust in the tailing pond through indoor experiments.Three conventional slope protection plants with strong adaptability(Bermudagrass,Astragalus,Ryegrass)were selected to study their adaptability to the tailings environment,select copper tailings,p Hosp Hate tailings as the testing tailings,and natural soil were selected as a control soil sample.After that,the effect of spraying dust suppressant on plant growth was explored.The results shown that calcium chloride is weakly acidic,it has a strong corrosive and destructive effect on grass seeds,The grass seeds cannot germinate and grow in the tailings sprayed by calcium chloride.The spraying of polyacrylamide can enhance the water-holding capacity of the tailings,It can provide water for the germination and growth of grass seeds.The results also shown that the bermudagrass requires a high-growth environment,the germination rate of it is extremely low in this test environment.The Astragalus and Ryegrass can adapt to the tailings environment,It can enhance the shear resistance of tailings,by entangle and articulate tailings particles to form large.(6)The generation and diffusion process of tailings dust was studied by numerical simulation method.The Fluent analysis module in ANSYS software was used to explore the speed and pressure changes of the wind flow through the dam,and explored the dusting and diffusion process of the dry beach of the tailings pond after spraying the dust suppressant.The results shown that the wind speed and wind pressure at the convex change of the tailings dam slope face in the windward state change greatly,and the local wind speed is significantly increased,which made the tailings particles easily peeled and lifted by the wind,so that a higher concentration of dust is formed locally.The results also shown that the dust on the dry beach of the tailings pond without the dust suppression agent is mainly concentrated at 10?30m away from the top of the dam.The closer to the top of the dam,the higher concentration of dust from the tailings.And with the increase of wind speed,the concentration and impact height of the dust gradually increase.On the contrary,the dust concentration of the tailings spraying the dust suppressant is significantly reduced due to the increase in density.