| In view of the recycling methods of crystalline silicon cutting powder,there are many problems,which include complex process,large environmental pollution and high treatment cost.The crystalline silicon cutting powder has been applied by iron and steel smelting process in this paper.The physics and chemistry of powder analysis showed that the main components of powder are SiC(47.8%,mass fraction),Si(22.9%),SiO2(21.4%)and iron oxide(7.9%),which particles size distribution range is 1.0?23.8 ?m.The large particles are SiC and small particles are Si,SiO2 and iron oxide.In the process of iron and steel smelting,a large amount of Si and SiC are needed.The thermodynamic analysis proves that it is feasible to use powedr to produce taphole clay and deoxidant.Therefore,this paper has studied the effect of powder application in taphole clay,and taphole clay properties have been tested when adding 0,5%,10%and 15%powder.The results show that:(1)With the increasing amount of powder,the apparent porosities were 38.76%,28.31%,21.47%and 18.75%;Bulk densities were 1.73 g/cm3,1.99 g/cm3,2.17 g/cm3 and 2.18 g/cm3;Compressive strengths were 5.40 MPa,12.70 MPa,17.51 MPa and 19.11 MPa;Flexural strengths were 8.45 MPa,9.98 MPa,10.95 MPa and 12.80 MPa;Line ratios were-0.43%,-0.86%,-1.81%and-2.74%;Erosion amounts were 0.46 mm,0.34 mm,0.21 mm and 0.08 mm.(2)XRD analysis showed that with the powder adding amount variation,taphole clay main components had no changing;SEM analysis showed that with the powder adding amount variation,taphole clay surface gradually got densification and holes gradually got small.This phenomenon showed that powder particals were filled into the taphole clay was very easy for its small partical;EDS analysis showed that with the powder adding amount variation,the amount of mullite gradually increased,which inhibated the decomposition of kyanite expansion.For this reason,line ratio of taphole clay gradually increased.This paper has studied the effect of powder application in deoxidant,and deoxidization rate and inclusions of steel have been tested when adding 1.5 g/kg and 2.5 g/kg powder.The results show that:(1)With the increasing amount of powder,the oxygen content in molten steel gradually decreased.The deoxidization rates were 1.032×10-4/min,3.6×10-6/min,6.3×10-6/min and 4.3×10-6/min when molten steel was added 1.5 g/kg powder in molten steel.The deoxidization rates were 1.072×10-4/min,2.16×10-5/min and then equilibrium in 9 min when molten steel was added 2.5 g/kg powder in molten steel.Microscopic analysis shows that the inclusions on the steel surface were uniformly distributed and its size and amount were small and many after adding 1.5 g/kg powder.However the results were opposite to adding 1.5 g/kg powder.(2)Dynamics analysis showed that the deoxidation rates were very quickly in early time,because the reaction impetus was very strong for its high concentration.According to the Stokes's formula,the floating speed of deoxidization products is related to its radius.The deoxidization products were easy to aggregate and form large radius for its nucleation interfaces were many after adding 2.5 g/kg powder.However the results were opposite to adding 1.5 g/kg powder. |
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