【作者】 张洋；

【导师】 魏国；

【作者基本信息】 东北大学 ， 钢铁冶金， 2018， 硕士

【摘要】 针对晶体硅切割粉料回收方法存在工艺复杂、环境污染大及处理成本高等问题,本研究提出在钢铁冶炼过程中对晶体硅切割粉料加以回收利用。通过对晶体硅切割粉料的物理、化学分析发现:粉料的主要成分是SiC(47.8%,质量分数,下同)、Si(22.9%)、SiO2(21.4%)和铁的氧化物(7.9%),其颗粒的尺寸分布范围是1.0～23.8 ltm,且粉料中的大颗粒为SiC,小颗粒为Si、SiO2和铁的氧化物。在钢铁生产过程中,炮泥和脱氧剂的生产原料需要大量的Si与SiC,且热力学分析表明粉料用做炮泥和炼钢脱氧剂的生产原料是可行的。一、本研究通过实验来考察粉料用做炮泥生产原料的效果,并测定添加量为0、5%、10%和15%时炮泥的性能指标变化。结果表明:(1)随着粉料添加量的增多,炮泥的显气孔率依次为38.76%、28.31%、21.47%和18.75%;体积密度依次为 1.73 g/cm3、1.99 g/cm3、2.17 g/cm3和2.18 g/cm3;耐压强度依次为 5.40 MPa、12.70 MPa、17.51 MPa 和 19.11 MPa;抗折强度依次为 8.45 MPa、9.98 MPa、10.95 MPa 和 12.80 MPa;线变化率依次为-0.43%、-0.86%、-1.81%和-2.74%;侵蚀量依次为0.46 mm、0.34 mm、0.21 mm和0.08 mm,炮泥的性能得到一定改善。(2)对烧后的炮泥进行XRD分析表明,粉料添加量变化对炮泥主体成分影响不大,与理论分析一致;SEM分析表明,随着粉料添加量的增多,炮泥表面逐渐致密化且孔洞数量大幅度降低,这说明粉料粒度较小,可以填充进炮泥孔洞,改善其显气孔率与体积密度,从而间接影响抗弯、抗折强度及侵蚀量;EDS分析表明,随着粉料添加量的增多,炮泥中的莫来石含量逐渐增多,抑制了蓝晶石的分解膨胀反应,使得线变化率逐渐增大。二、通过实验考察了粉料用做炼钢脱氧剂的效果,并测定了添加量为1.5 g/kg和2.5 g/kg时对脱氧速率和钢样夹杂物的影响。结果表明:(1)随着粉料添加量的增多,脱氧速率逐渐加快,添加1.5 g/kg粉料时,脱氧速率依次为 1.032× 10-4/min、3.6×10-6/min、6.3×106/min和 4.3×10-6/min;添加 2.5 g/kg 粉料时,脱氧速率依次为1.072×104/min和2.16×10-5/min,并在9 min时达到脱氧平衡;微观分析可知,添加1.5 g/kg粉料脱氧后,钢样表面的夹杂物分布均匀,且半径小、数量多;添加2.5 g/kg粉料脱氧后,钢样表面的夹杂物亦均匀分布,但半径大,数量少。(2)动力学分析表明,脱氧前期粉料脱氧速率较快,这是因为前期粉料在钢液中的浓度较大,反应的推动力较强;由斯托克斯公式可知,脱氧产物的上浮速度与其半径有关,添加2.5 g/kg粉料时,脱氧产物的形核界面较多,产物易聚集且形成半径较大脱氧产物,上浮速度较快,而添加1.5 g/kg粉料反之。更多还原

【Abstract】 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 μm.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.更多还原