Study On The Process Of Chemical Breaking Soil Crust In Magnesite Mining Area

In recent years,the production and processing of people constantly develop high strength and magnesite resources,it has caused a serious environmental problem,for example,the most severe ecological imbalance,soil erosion,agricultural production,water and air pollution and other ecological problems.This study is about the investigation and research on the characteristics of the soil around the magnesite mining area, and found that the soil polluted seriously by magnesium dust,not only the soil quality degradation,but also makes a lot of crops around magnesite mining area death,some places have not even a blade of grass grows,there is large areas of abandoned land and the piles of slag,the physical and chemical properties of soil has gradually deteriorated.The physical and chemical reaction between magnesite mine soil and atmospheric dust occur in wet conditions and form a dense soil,this dense layer is crust,which is the main component of magnesium oxide,magnesium carbonate,magnesium hydroxide and basic carbonate,this kind of soil with the rainfall have aged and dispersed,the decrease of soil porosity lead to the decrease of soil permeability.At present,the primary focus is to strengthen the study on the repair method of soil magnesite resources development region,it has important significance to improve the soil quality,to inhibit crust development and characteristics of soil degradation trend,and to restore the ecological environment around the magnesite mining area.Soil permeability is an important index to measure soil structure characteristics,this study utilizes artificial filled soil column method for measurement of magnesite mining area contaminated soil permeability,and the improvement effect of different soil modifiers on pollution of magnesite magnesite mining area,the study has chosen citric acid,polyacrylamide,gypsum,calcium phosphate,humic acid,ammonium sulfate as modifier.The morphology and structure of soil surface crust was observed by SEM,as well as the product of crust after citric acid,the product of crust after PAM,the product of crust after gypsum.The phase composition of product of crust after modifier was analyzed by X-ray powder diffraction method.Reduction leaching of citric acid will cause an increase in the activity of magnesium ion,citric acid reacts with magnesium carbonate to form a complex and precipitate form the filtrate.Polyacrylamide can relieve the dispersion of soil aggregates and then inhibit the development of soil crust.Gypsum can increase the concentration of electrolytes,it prevents the dispersion of soil clay.Ammonium sulfate is acidic in the soil solution,it could significantly regulate the alkalization ofcontaminated soil.The result of the experiment showed that the effect of the inhibition of the development of the crust was citric acid,PAM,ammonium sulfate,gymsum.