共查询到19条相似文献,搜索用时 93 毫秒
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氧化镁真空碳热还原法炼镁的工艺研究 总被引:1,自引:1,他引:0
采用物料失重率、金属Mg还原率、X射线衍射(XRD)与扫描电子显微镜(SEM)等手段与方法,研究了真空条件下氧化镁碳热还原温度、物料造球成型压力、物料配比、碳热还原保温时间以及催化剂对氧化镁碳热还原法炼镁工艺的影响。研究结果表明,在30~100 Pa时,碳热还原温度高于1553 K,控制物料压块压力为8 MPa,此时物料失重率最大,最有利于氧化镁的还原。随着焦煤还原剂与氧化镁摩尔比以及碳热还原时间的增加,碳热还原反应速率加大,还原率提高,但是变化效果不明显,加入氟盐CaF2后,物料失重率明显提高,添加CaF2的质量超过物料总质量的3%时,物料失重率超过95%,还原率也相应大幅提高。因此,选择适当的焦煤还原剂与氧化镁摩尔比值以及碳热还原时间,添加超过3%CaF2,将有利于该法炼镁过程的顺利进行与金属Mg还原率的提高。此研究为真空碳热法从氧化镁中提取金属Mg工艺提供了很好的实验依据。 相似文献
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提出真空硅热还原制备Mg-Li合金的新方法.热力学分析结果表明,硅热法还原制备Mg-Li合金的适宜条件为:真空度≤102 Pa,还原温度≥1400 K;还原温度为1473 K时,同步液化冷凝镁锂的温度T<1062 K,同步固化冷凝镁锂的温度T<454 K.在温度1200℃、真空度10~20 Pa、还原时间2h和冷凝温度168~210℃的条件下进行实验研究,制得结晶较好的块状Mg-Li合金.X射线衍射结果表明,Mg-Li合金主要成分为Mg、Li3Mg17和Li0.92Mg4.08,残渣主要成分为Ca2SiO4.扫描电镜分析表明,Mg-Li合金呈羽毛状.X射线荧光及原子吸收分光光度计检测表明,Mg-Li合金中镁含量与锂含量分别为77.58%,8.27%. 相似文献
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新法真空铝热还原炼镁的研究 总被引:1,自引:0,他引:1
对以煅后白云石和煅后菱镁石为原料,以铝粉为还原剂的新法炼镁技术的热力学进行了分析,并进行了真空热还原实验。通过X射线衍射和扫描电子显微镜对还原渣的主要物相与物质形态进行了分析。实验结果表明:以煅后白云石和煅后菱镁石为原料,以铝粉为还原剂的新法真空热还原炼镁技术是可行的,在还原温度1200℃,还原时间2 h,铝粉过量5%和无氟盐添加剂的条件下,氧化镁的还原率可达90%,CaF2或MgF2的添加可大幅度地提高还原过程中氧化镁的还原率,降低还原温度。还原后还原渣主要物相为CaO.2Al2O3,还原渣中氧化铝的含量在65%以上,氧化硅含量低于2%,是一种非常适合生产氢氧化铝的原料。 相似文献
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热力学分析了铝还原剂从MgO、2MgO·B2O3和3MgO·B2O3中提取金属镁的化学反应。实验研究了制团压力、CaF2添加、还原温度、还原剂用量等对氧化镁还原率的影响。结果表明,适当地提高反应物料的制团压力有利于改善氧化镁还原率,但较大的制团压力会导致球团孔隙率降低,从而阻碍了产物Mg蒸气的释放以及氧化镁还原过程。对还原渣的X射线衍射分析表明,铝热还原生成的Al2O3会先与CaO结合。添加少量的Ca F2有利于氧化镁的还原,CaF2与还原渣结合成11CaO·7Al2O3·Ca F2。添加3%的CaF2,制团压力为90 MPa,在1200℃下还原120 min,氧化镁的还原率为85%,铝利用率为74%。 相似文献
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提出一种以煅烧后的菱镁石和白云石为原料, 真空铝热还原一步法制备镁钙合金的方法。通过正交试验研究了四种影响金属还原率主要因素的主次关系, 然后对这些因素进行实验研究, 并通过ICP发射光谱仪、扫描电子显微镜及X射线衍射对金属产物及还原渣进行了分析。结果表明, 铝粉过量系数和制块压力对MgO、CaO还原率的影响较大, 还原温度和还原时间次之, 在制块压力为150 MPa, 还原温度1250℃, 还原时间180 min, 铝粉过量系数10%的条件下, MgO和CaO还原率最高, 分别为93.1%和49.5%。 相似文献
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通过往煅烧白云石中添加适量的Al2O3和SiO2,使其在1500~1600℃之间形成熔融炉渣,并在真空下采用硅铁还原液态渣中的MgO。研究了造渣剂对MgO还原率的影响,结果表明,在能够获得熔融炉渣的情况下,增大Al2O3/SiO2比能够极大地提高渣中MgO的还原率,理想的炉渣成分为32.0%CaO-23.0%MgO-35.0%Al2O3-10%SiO2。同时,对该炉渣进行了正交实验,通过分析得出影响MgO还原率因素的顺序依次是:反应温度、还原剂硅铁添加量、反应时间、催化剂CaF2添加量。在熔融还原工艺参数为:反应温度1600℃,还原剂硅铁添加量n(Si)/n(2MgO)=1.2,反应2h,催化剂CaF2添加量3%条件下,渣中的MgO还原率高达97.3%。 相似文献
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T. Kameda T. Yoshioka M. Uchida A. Okuwaki 《Journal of Materials Science Letters》2002,21(22):1747-1749
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为改善再生铝中富铁相形态,提高其合金性能,本文采用搅拌摩擦加工对Al-Si-Fe合金进行了研究。利用金相显微镜、扫描电镜、万能拉伸试验机、显微硬度计及图形分析仪等研究了加工速度对Al-Si-Fe合金组织和性能的影响。研究结果表明:搅拌摩擦加工后,第二相形态由针状、棒状向细小且均匀分布的球状、粒状和短棒状转变,前进侧热机械影响区组织得到一定程度的细化且具有明显的取向,而返回侧热机械影响区的组织则保持铸态形貌特征的组成。加工中心区的富铁相和共晶硅平均长度较基材分别降低了86.5%、37.4%,而圆整度则分别提高了7.8倍和2.1倍以上,富铁相细化效果优于共晶硅;随着加工速度的提高,富铁相的平均长度逐渐增大,而圆整度则逐渐降低;但加工速度对共晶硅的平均长度影响较小,但圆整度逐渐降低。加工区的抗拉强度、屈服强度大幅降低,最高降幅达55.4%,而伸长率最大可提高6.8倍。随着加工速度的提高,其抗拉强度、屈服强度有所提高,伸长率则逐渐降低,最大降幅达到19.3%。搅拌摩擦加工后,Al-Si-Fe合金晶粒细化,材料性能提升。 相似文献
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首先初选6种钎料,通过检测钎缝的机械性能(主要指剪切强度)并结合微观分析对钎料进行优选,确定了1~2种适用于钎焊SN2025钢与硬质合金的钎料;针对选定的钎料,进行真空钎焊工艺参数的正交优化试验,同样是通过检测钎缝的机械性能来判定最佳的工艺参数. 相似文献
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Carlos F. Linares Freddy Ocanto Pablo Bretto Maricela Monsalve 《Bulletin of Materials Science》2014,37(4):941-944
A hydrocalumite-type solid was synthesized by the homogeneous co-precipitation method by using Ca and Al nitrate solutions in a basic medium (NaOH). This solid was calcined at 700 and 900 °C, respectively. Then, solids were characterized by X-ray diffraction, FT-IR spectroscopy and BET surface area measurements. Finally, these solids were tested as antacids by using a synthetic gastric juice. Results showed that calcined samples were able to neutralize the synthetic gastric juice in more extension as an as-synthesized hydrocalumite; however, the last solid showed better conditions as a potential antacid. 相似文献
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This article studies the mechanism of iron reduction in magnesium alloy melt by investigating the iron concentrations in different
parts in the melt with different holding time. The iron concentrations at the top, the center and the bottom of the melt are
measured with the holding time of 300, 1800 and 7200 s. The elements in the sludge settling down in the crucible are also
determined by ICP. With the increasing holding time, the iron content in the upper part of the melt decreases and that in
the lower part of the melt increases. And the iron content in the sludge increases rapidly. The iron concentrations in the
melt and the sludge change little with longer holding time than 1800 s. Among the three iron reduction agents B2O3, MnCl2 and TiO2, B2O3 has the highest iron reduction efficiency (IRE). IRE of B2O3 is as two times and five times as IRE of MnCl2 and IRE of TiO2 respectively. Formation of FeB and settling of it into melting sludge are believed to be the primary mechanism of iron reduction
by B2O3 processing. The mechanism of iron reduction in magnesium melt by MnCl2 or TiO2 processing is studied by thermodynamic analysis. Formation of substance containing MnFeAl or TiFe with high density and high
melting point and settling of them into melting sludge are suggested to be the mechanism of iron reduction by MnCl2 or TiO2 processing. 相似文献
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Anuj Kumar Amanpal Singh Mukesh Kumar Dinesh Kumar Sumit Barthwal 《Journal of Materials Science: Materials in Electronics》2011,22(9):1495-1500
The Ni–P and Ni-Co-P alloy thin films were deposited on silicon substrates with electroless technique. The solid state metallurgical
reactions were investigated with silicon for the viewpoint of Co co-deposition effect. The alloy film kept amorphous state
with increasing Co content even though the P content decreased. The films become more amorphous, and the thermal stability
increased with increment of Co content in the deposit. The Co content was varied from 11.013 to 45.068 wt% while P content
was decreased from 9.340 to 6.491 wt% by varying the concentration of components in electroless deposition baths. The thermal
stability was examined by X-ray diffractometer (XRD), four probe, and atomic force microscopy (AFM). The results indicated
the Ni-Co-P alloy films with lower P content show the higher thermal stability then the ordinary Ni–P films and prevent the
silicidation at low temperature because the Ni crystallization formation suppressed by the co-deposition of Co. 相似文献