Study On Preparation Technology And Properties Of Artificial Soil Based On Coal Gangue

Global land resources are in short supply,and most areas are in poor soil conditions.At the same time,rapid urbanization and fossil energy mining also occupy and consolidate a large amount of soil resources.In view of my country’s energy structure,coal mining areas have been destroyed due to mining and coal gangue.The accumulation of solid waste wastes a lot of land,so repairing coal mining areas to restore the ecological function of the soil is an important research direction to solve the problem of land resources in my country and consolidate the cornerstone of soil safety.Because the current restoration methods use a large amount of guest soil not only destroys the ecological environment of the land taken,but also has weak water and fertilizer retention capacity of the soil after restoration.At the same time,there are also problems such as water and soil erosion,which necessitates regular paving of new guest soil every year.This thesis researched and prepared a coal gangue-based artificial soil with better properties of natural soil.Compared with natural soil,this artificial soil has better water retention,erosion resistance,and fertilizer retention properties.It can be widely used in artificial planting,soil improvement,Ornamental green plants,park gardens and other plant cultivation;the soil uses coal gangue as the main raw material,which not only solves the problem of large amounts of coal gangue,but also expands the source of high-quality soil,providing new technical support for my country’s food security and vegetable basket project.The main contents are as follows:（1）Use coal gangue powder as the main raw material,cement as the cementing material,and aluminum powder as the foaming agent to make cement-gangue-based artificial soil.Through the optimization experiment of process conditions,the cement-gangue-based artificial soil with the best comprehensive performance is obtained.The optimized process conditions are as follows:cement mixing amount is 5%,coal gangue powder mixing amount is 95%,water-cement ratio 0.62,aluminum powder addition amount is 0.05%,and temperature is 50℃.Under these conditions,the water retention capacity of cement-gangue-based artificial soil is 0.86 g water/g soil is better than natural soil,with an increase of about 51%and a loss rate of0.93%,which is about 87%lower than that of natural soil.It has good thermal insulation performance and has a porosity of 56.82%,which is an increase of about 34.5%compared with natural soil.The pore volume is0.5696 m L/g,which is about 86.8%more than natural soil.（2）The multi-component self cementitious powder coal gangue based artificial soil was prepared by using multi-component self cementitious powder instead of cement as cementitious material and the same process conditions.The optimal process conditions were as follows:12%of multi-component self cementitious powder,88%of coal gangue powder,0.66of water cement ratio,0.07%of aluminum powder and 50℃of temperature The water holding capacity of gangue based artificial soil is 0.80 g water/g soil,which is about 40%higher than that of natural soil,the loss rate is1.53%,which is about 78%lower than that of natural soil,the thermal insulation performance is good,the porosity is 47.63%,which is about 12.8%higher than that of natural soil,and the total pore volume is 0.5552 m L/g,which is about 82%higher than that of natural soil.（3）The 28-day cumulative release rates of cement-gangue-based artificial soil and multi-component self-cementing powder-gangue-based artificial soil are 65.13%and 61.15%,respectively,which can reach the standard of slow-release fertilizer.The natural soil was mixed with two kinds of coal gangue-based artificial soils in different proportions for plant cultivation experiments.When the cement-gangue-based artificial soil accounts for 20%,the highest seedling emergence rate is 78%,and the average plant height is 16.21 cm.When the components are self-gelling powder-coal gangue artificial soil accounted for 60%,the seedling emergence rate is the highest 85%,and the average plant height is 15.06 cm,which has a better effect than plants cultivated with natural soil alone.The heavy metal content of the two kinds of coal gangue-based artificial soils in the p H=5aqueous solution and the cultivated plants are very small and meet the standard.In order to be suitable for the p H environment of common plant growth,the p H of the two kinds of coal gangue-based artificial soils after treatment with CO₂ carbonization technology can be reduced to between 7-8.Through the research of this paper,we use coal gangue as the main raw material to prepare artificial soil,which not only realizes the bulk resource utilization of coal gangue,but also expands the source of high-quality soil.In addition,the use of CO₂ carbonization technology has realized the contribution to carbon emission reduction.