钢渣组成对其自粉化过程影响的研究

发布时间：2018-07-09 20:44

本文选题：转炉钢渣 + 钢渣组成　；参考：《安徽工业大学》2015年硕士论文

【摘要】：钢渣微粉化是目前实现钢渣综合利用的有效途径之一,但是常见钢渣,如转炉钢渣、不锈钢电炉渣等难磨、难粉化,是钢渣微粉化的重要制约因素。要实现钢渣高效利用,对钢渣粉化方式和影响条件的研究是十分必要的。常见钢渣的主要矿相为硅酸三钙(即C_3S),硅酸二钙(即C_2S),铁铝酸钙(即Ca2(Al,Fe)2O5)及镁铁相固溶体(即MgO2Fe0)等。其中C_2S在725℃时会发生β-C_2S向γ-C_2S的晶型转变,这个过程伴随着约11%的体积膨胀,产生的强烈内应力可使C_2S粉化。若钢渣中大量发生此类晶型转变将能实现钢渣的自粉化,这是一种简单、低耗、有效的钢渣粉化方式。本论文在前期钢渣自粉化实验的基础上,利用XRD全谱拟合精修方法,结合Factsage热力学相平衡计算,研究了实际钢渣中含有的Cr、P等元素对β-C_2S向7-C_2S晶型转变的影响,具体分析了Cr、P含量变化对p-C_2S向y-C_2S的晶型转变率以及钢渣自粉化的影响,确定了钢渣实现自粉化时渣中Cr、P的含量限制范围,为钢渣自粉化提供了理论依据和渣成分条件,对提高钢渣易磨性、实现钢渣综合利用有积极的现实意义。本论文的研究结果表明：(1)对于纯C_2S的自粉化实验,当Cr_2O_3含量为0.5%时,高温冷却后,C_2S中p-C_2S占比尽管达到68.8%,但C_2S仍能发生自粉化,p-C_2S向γγ-C_2S的晶型转变产生的自粉化效应显著；当纯C_2S中Cr_2O_3含量为1%时,冷却后,C_2S中晶型转变得到的γ-C_2S占比已小于18.4%,C_2S不会出现粉化现象,此含量Cr_2O_3的掺入抑制了p-C_2S的晶型转变,影响C_2S的自粉化。当纯C_2S掺入P_2O_5时,若P_2O_5的含量小于1%,则对β-C_2S晶型转变的影响并不明显,高温冷却后,C_2S仍有自粉化；当P_2O_5的含量达到1.25%时,冷却后C_2S中有a'H-C_2S出现,而生成的γ-C_2S占比小于20.6%,试样也不再出现自粉化。热力学分析表明,纯C_2S中掺入Cr_2O_3或P_2O_5能促进C_2S中液相的生成,使Cr3+、P5+外掺离子向C_2S中的固溶,从而影响β-C_2S向γ-C_2S的晶型转变,减弱了C_2S的自粉化效果。纯C_2S掺杂Cr_2O_3或P_2O_5的自粉化实验结果也表明,当C_2S中Cr_2O_3含量大于1%或P_2O_5含量大于1.25%时,高温冷却后,C_2S中γ-C_2S占比均小于20.6%,此时β-C_2S向γ-C_2S晶型转变不充分,体积膨胀效应导致的自粉化内应力不足,C_2S将不会出现自粉化现象。(2)对于转炉钢渣的自粉化实验,采用了CaO 45%-SiO2 18%-MgO 10% Fe2O3 27%的四元合成转炉渣,分别计算了渣中C_2S的生成量,分析了不同含量Cr_2O_3或P20s掺入时转炉钢渣的自粉化效果。当钢渣中掺入Cr_2O_3时,少量Cr_2O_3对渣中p-C_2S晶型转变的影响较小。当渣中Cr_2O_3含量在0.25%-2%范围内时,其影响p-C_2S晶型转变的能力并没有随着掺量的增加发生明显的变化,转炉钢渣仍呈现出完全自粉化的状态：当Cr_2O_3含量达到3%时,其影响p-C_2S晶型转变的能力明显增加,渣中生成γ-C_2S占C_2S生成总量小于35.7%,钢渣没有出现自粉化。当钢渣中掺入P_2O_5时,若P_2O_5含量为0.25%,则钢渣仍能完全自粉化；当P_2O_5含量为0.5%时,转炉钢渣中β-C_2S晶型转变受到抑制,生成γ-C_2S的占比小于35.3%,钢渣没有出现自粉化现象；随着P20s含量的进一步增加,渣中生成γ-C_2S的占比进一步降低,钢渣均不再自粉化。并且当转炉钢渣中P_2O_5含量达到1.5%时,渣中开始有α'H-C_2S出现。上述结果表明,要实现转炉钢渣的自粉化,则渣中Cr_2O_3含量必须低于3%,或渣中P20s含量必须低于0.5%,此时转炉钢渣内γ-C_2S占C_2S生成总量均小于35.3%,才能达到钢渣自粉化的效果。特别是对实际转炉钢渣中P含量要严格控制,渣中过高P含量将会抑制钢渣的自粉化,达不到提高钢渣易磨性的效果。
[Abstract]:The micro powder of steel slag is one of the effective ways to realize the comprehensive utilization of steel slag at present. But the common steel slag, such as the slag of converter steel, the slag of stainless steel electric furnace and so on, is an important restriction factor for the micro powder of steel slag. It is necessary to study the method of slag powder and the influence conditions for the high efficiency utilization of steel slag. The phase is three calcium silicate (C_3S), calcium silicate two (that is, C_2S), calcium ferric aluminate (Ca2 (Al, Fe) 2O5) and magnesium iron phase solid solution (MgO2Fe0). In which C_2S is at 725 degrees C, the crystalline transformation of beta -C_2S to gamma -C_2S will occur. This process is accompanied by a volume expansion of about 11%, and the strong internal stress can make C_2S powder. If a large number of such crystals occur in steel slag, a large number of such crystals occur. This paper is a simple, low consumption and effective method for slag pulverization of steel slag, which is a simple, low consumption and effective method for slag pulverization. In this paper, on the basis of the experiment of self powdering of steel slag, this paper studied the transformation of Cr, P and other elements containing Cr, P and other elements in the actual steel slag to the 7-C_2S crystal form in the actual steel slag on the basis of the experiment of the self powdering of steel slag. The influence of the change of Cr and P content on the transformation rate of p-C_2S to y-C_2S and the self powdering of steel slag is analyzed. The limit range of Cr and P content in slag is determined, which provides the theoretical basis and slag composition conditions for the self powdering of steel slag. It has a positive realistic meaning for improving the grinding property of steel slag and realizing the comprehensive utilization of steel slag. The research results of this thesis show that: (1) for pure C_2S, when the content of Cr_2O_3 is 0.5%, the p-C_2S occupation ratio in C_2S is 68.8%, but the C_2S can still be self powdering, and the effect of p-C_2S to the crystal form of gamma ray -C_2S is obvious. When the Cr_2O_3 content is 1% in the pure C_2S, the cooling, C_2S The ratio of gamma -C_2S to crystal transformation is less than 18.4%, and C_2S will not be powderizing. The addition of Cr_2O_3 inhibits the crystal transformation of p-C_2S and affects the self pulverization of C_2S. When pure C_2S is added to P_2O_5, if P_2O_5 content is less than 1%, the effect on the transformation of the crystal form is not obvious, and C_2S is still self powdering after high temperature cooling; when P is in the P P_2O_5 When the content of _2O_5 reaches 1.25%, a'H-C_2S appears in C_2S after cooling, and the ratio of the generated gamma -C_2S is less than 20.6%, and the sample is no longer in powder. The thermodynamic analysis shows that the addition of Cr_2O_3 or P_2O_5 in pure C_2S can promote the formation of the liquid phase in C_2S, and make the Cr3+ and P5+ doped ions to the solid solution in C_2S, thus affecting the crystal form of the beta -C_2S. The self powdering effect of C_2S is weakened. The results of self powdering of pure C_2S doped Cr_2O_3 or P_2O_5 also show that when Cr_2O_3 content in C_2S is greater than 1% or P_2O_5 content is greater than 1.25%, the proportion of gamma -C_2S in C_2S is less than 20.6% after high temperature cooling, and at this time, the transformation of beta -C_2S to gamma -C_2S crystal is not sufficient and the volume expansion effect is in the self powdering. When the stress is insufficient, C_2S will not be self powderizing. (2) for the self powdering experiment of converter steel slag, four meta converter slag of CaO 45%-SiO2 18%-MgO 10% Fe2O3 27% is used to calculate the formation of C_2S in the slag, and the self powdering effect of the steel slag with different content of Cr_2O_3 or P20s is analyzed. When the slag is added to the slag, the slag is added to the slag. A small amount of Cr_2O_3 has little effect on the transformation of p-C_2S crystal in the slag. When the content of Cr_2O_3 in the slag is within the range of 0.25%-2%, the ability to influence the transformation of p-C_2S crystal is not obviously changed with the increase of content. The converter steel slag still presents a state of complete self pulverization. When the content of Cr_2O_3 reaches 3%, it affects the transition of the p-C_2S crystal. The capacity of the slag is obviously increased, the production of gamma -C_2S in the slag is less than 35.7%, and the slag of steel is less than 35.7%. The slag has no self powdering. When the content of P_2O_5 is 0.25%, the slag can be completely self powdered when the content of P_2O_5 is 0.25%. When the content of P_2O_5 is 0.5%, the transformation of the beta -C_2S crystal form in the converter steel slag is suppressed, the ratio of the generated gamma -C_2S is less than 35.3%, and the slag is no more than the slag. With the further increase of the P20s content, the proportion of gamma -C_2S in slag is further reduced and the slag is no longer self powdering. And when the P_2O_5 content of the converter slag reaches 1.5%, the slag begins to appear in the slag. The results show that the Cr_2O_3 content in the slag must be lower than that of the slag in the slag. 3%, the content of P20s in the slag must be less than 0.5%. At this time, the total amount of gamma -C_2S in the slag of converter steel slag is less than 35.3%, in order to achieve the effect of slag self pulverization. Especially, the P content in the slag of the actual converter steel slag should be strictly controlled. The high P content in the slag will inhibit the self pulverization of steel slag, and the effect of improving the grinding property of steel slag can not be achieved.
【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X757

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