Study On The Resources Utilization Of A Coal Slime In Guangwang Group Of Sichuan Coal Mine

The raw coal washing process will produce a large amount of slime.The slime has the characteristics of fine particle size,high viscosity,high moisture content,very difficult dehydration,low calorific value and high ash content.Guangwang Group of Sichuan Coal produces millions of tons of slime every year,which is stored in open air all the year round.It not only occupies a large amount of land,but also pollutes the environment.In view of this phenomenon,this paper first studies the physical properties,chemical composition and mineral composition of the slime.Secondly,on this basis,it studies the preparation of cement active mixtures,concrete admixtures and large-scale utilization of building materials such as red brick and light ceramsite fired by slime and shale.Comprehensive utilization has important reference value.The results show that the slime has fine natural particle size,D90 110.2?m,moisture content 20%,loss of ignition 31.3%,calorific value 1875 kcal/kg,plasticity index 19,and good plasticity.The main chemical constituents are Si O2,Al2O3,Ca O,Fe2O3,K2 O and Mg O.The main mineral components are kaolinite,illite,quartz,calcite and other minerals.The results show that the calcination temperature,holding time and particle size distribution of the calcined products have great influence on the pozzolanic activity of the coal slime.When calcination temperature is 850 ?,holding time is 1.5 h and grinding fineness D90 20?m,the property index reaches the maximum,which is about 98%.The results show that the fluidity of concrete mixtures decreases gradually with the increase of the content of coal slurry.With the increase of sample content,the fluidity of concrete mixtures decreases gradually.When the coal slurry content is about 20%,and the water-cement ratio is 0.42,the compressive strength of concrete specimens is higher,and good working performance can be guaranteed.The research results of red bricks fired with coal slime and shale show that when coal slime: shale = 3:7,calcination temperature 1050?,and holding time is 4 hours,the compressive strength of red bricks for construction reaches 38.05 MPa,which meets the requirements of MU30 strength grade and water absorption less than 16% in the national standard of the People's Republic of China "Sintered Ordinary Bricks"(GB5101-2003).The results of light ceramsite prepared by mixing slime and shale show that when slime: shale = 6:4,preheating temperature is 550? for 25 minutes,and calcined at 1100? for 25 minutes,the cylinder compressive strength of the ceramsite is 34.29 MPa,the water absorption rate is 8.33%,and the stacking density is 675 Kg/m3.It meets the basic performance requirements of 700-grade high strength light and coarse aggregates in the national standard of the People's Republic of China "Light aggregate and its test method(Part 1): Light aggregate"(GB/T 17431.1-2010)(water absorption < 10%,bulk density range 600 < X < 700,barrel compressive strength label 30 MPa).