| Stainless steel production capacity continues to increase.The circumstance is bound to lead stainless steel smelting materials demand growth,such as Nickel,chromium and so on.How to solve the problem of subsequent raw material supply has also become the focus of the industry.China's nickel and chromium resources are relatively scarce,mainly relying on imports,and stainless steel scrap resources are also extremely limited,therefore,how to solve the problem of high speed growth of stainless steel raw materials supply and security,will be the primary issue for domestic stainless steel enterprises to consider.Benefit from the continuous diversification of stainless steel smelting equipment and the continuous improvement of the smelting process,all kinds of raw materials which contain nickel and chromium can be tried as raw materials for smelting stainless steel,therefore the innovation of stainless steel technology and raw material preparation technology will be the important research direction for the sake of reducing the cost of stainless steel production in the future.The Ni(OH)2 is roasted at the high temperature in the laboratory,and the range of temperature and moisture content of its free water and crystal water completely discharging is observed.At the same time,the transformation temperature of Ni(OH)2 and NiO is observed through the diffraction and electron microscope.In addition,the pellet formation of powder or granule materials has been preliminarily tested and explored.The alloying and yield of oxide materials in AOD were studied.Through the model calculation,oxide addition amount under the condition of different hot metal,timing and amount of oxygen in different stages of the AOD converter,the temperature controlling is optimized and adjusted,the formation of technology of smelting stainless steel through mineral materials direct smelting is summarized.The production practice shows that:(1)When the temperature is 300?,the NiO begins to generate,and temperature is 550? after roasting,the Ni(OH)2 is completely change into NiO;(2)MoO3 has low melting point,it is quite volatile when the steelmaking temperature is above 1600?,but lime can restrain the volatilization of MoO3;(3)The chromium ore reduction influence by the carbon and chromium content in the melt.High carbon and low chromium can reduce of chromium ore at lower temperature.By increasing the alkalinity properly,the temperature of reduction(Cr2O3)can be reduced;(4)At hight tempture,the NiO is stability than Ni;(5)The chromium ore reduction temperature is highter than others,when the tempture beyond 1147?,the chromium ore reduction begins to generate.(6)Nickel ore is easier to be reduced than chromium ore;(7)Sample analysis have beeb carried on the slabs,and the inclusion is observed by microscopic.The inclusion are mainly containing Si,Ca,Al,Mg,Mn and O,so the inclusions type is mainly spinel and silicate.Therefore,after using this kind of raw material,it has little effect on the purity of the steel and the quality of casting slab. |
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