An Industrial And Experimental Study For Three Products Teeter Bed To Produce Ultra-low Ash Coal

The coarse coal slime,produced by the original production system of Taixi Coal Preparation Plant,Ningxia Coal Industry,National Energy Group,including the heavy-medium magnetic separation tailings and coarse in flotation feed produced in the ultra-pure coal production system,has long been recovered only by general hydro-cyclone,causing a great deal of low ash components that contained in coarse coal slime was lost,and these low ash components enter the high ash product with an ash content of 8% or an ash content of 10%,and results in a decrease in the yield of high value-added ultra-pure coal products(ash content: 3.00%).In the current production and operation situation,due to the limited reserves of ultra-pure Taixi anthracite and the gradual decline in annual output,more efficiently use scarce Taixi anthracite resources is an important target of this research.The sampling analysis show that the coarse coal slime contain some-0.125 mm fine particles,which affects the separation accuracy of gravity separation.At the same time,the washability of coarse coal slime is extremely difficult so it is impossible to yield ultra-pure coal products by ordinary water medium separation.On the basis of the feed analysis,the technical transformation scheme is put forward: high-precision classification cyclone is adopted to remove fine particles below 0.125 mm,so as to provide narrow particle size range for subsequent water medium separation;Two-stage water medium coal backwash process is adopted to improve the separation accuracy.In this paper,the classification efficiency of water-only-cyclone is evaluated,and the possible products are simulated and calculated with TPS feed float-sink data.Then,Installed and debugged the teeter-bed separator.Optimize operating parameters to obtain required product ash.Finally,sampling and analysis are carried for feed and products under the optimal parameter condition,to validated with simulation results.Results show that the high-precision classification cyclone has a good effect on the preliminary desliming for coarse coal slime system.In the underflow products,the coarse coal slime content of +0.25 mm particle size grade is as high as 92.70%,mean very little fine particles,this provides good conditions for the separation of Three-Product teeter-bed System(TPS).Simulation results show that 3% ash could be produced only by one-step serration when the possible Error(E)less than 0.07,or by two-stage separation system with E=0.1 and recycling middlings upto 6 times asfeed.Different density composition feed can be separatd with different recycling ratios for ultra-low ash products,e.g.less than 3% ash.Generally,the yield of ultra-low ash coal is around 20%.According to the current market conditions,the preparation of ultra-low ash clean coal can bring huge economic benefits to the Taixi Coal Preparation Plant.