Study On Soil Improvement Of Reclaimed Forest Land In Mining Area By Modified Coal Gangue

In this study,coal gangue was collected from Fuxin open-pit mine in Liaoning province.The orthogonal experiment method was used to design modification experiment of coal gangue.The effects of modified coal gangue on soil physical and chemical properties of reclaimed forest land were investigated.The results provided theoretical basis for soil improvement of reclaimed forest land in Fuxin drainage field and the resource utilization of coal gangue.The main conclusions are as follows:(1)The optimal alkali modified conditions of Fuxin gangue were as follows:alkali concentration of 3%,modified time of 2h and modified temperature of 75℃.The optimal acid modified conditions were as follows:acid concentration of 5%,modified tiem of 2h and modified temperature of 70℃.(2)After adding acid modified coal gangue into reclaimed forest soil,the moisture content of soil was increased from 16%to 33.95%,the growth rate of moisture content increasing is 112%,the electrical conductivity of soil was increased from 273 us/cm to 348 us/cm,the proportion of electrical conductivity increasing is 27.4%and the bulk density of soil was decreased from1.61g/cm~3 to 1.46g/cm~3.After adding alkali modified coal gangue into reclaimed forest soil,the moisture content of soil was increased from 20.7%to 42.6%,the growth rate of moisture content increasing is 166.2%,the conductivity was increased from 273 us/cm to 378 us/cm,the proportion of electrical conductivity increasing is 38.6%,and the bulk density of soil was decreased from1.61g/cm~3 to 1.51g/cm~3.(3)After adding acid modified coal gangue into reclaimed forest soil,the pH value of soil was increased from 5.6 to 6.48.The content of soil organic matter was increased from 1.5g/kg to12.75g/kg.The total nitrogen content was increased from 0.663g/kg to 0.774g/kg.The content of total P was increased from 0.41g/kg to 0.493g/kg.The content of available P in soil was increased from 30.42 mg/kg to 47.867 mg/kg.The content of total k was increased from 13.1 g/kg to15.153g/kg.There was no significant difference between these three kinds of soil amendments in the increase of soil available K.After adding alkali modified coal gangue,pH value was increased from 5.6 to 7.12.The content of soil organic matter was increased from 1.5g/kg to 12.6g/kg,and the content of total nitrogen was increased from 0.663g/kg to 0.778g/kg.The content of total phosphorus was increased from 0.41g/kg to 0.493g/kg.Available phosphorus was increased from30.42 mg/kg to 42.32mg/kg.The content of total potassium was increased from 13.1 g/kg to18.238 g/kg.The content of available K increased from 200.32 mg/kg to 312.48 mg/kg.(4)After adding coal gangue,acid modified coal gangue and alkali modified coal gangue into the soil,the pH value,organic matter,total nitrogen,total phosphorus content of soil was increasing.The increase of the pH value,organic matter,total nitrogen,total phosphorus were positively correlated with the amount of modifier.The addition of coal gangue,acid-modified coal gangue and alkali-modified coal gangue has improvement effect on the increase of total K,and the increase of soil total K and available K is positively correlated with the amount of modifier.The total K and available K of soil was increase significantly by adding alkali-modified coal gangue.There are 47 diagrams,18 tables and 62 references in this paper.