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采用熔析———加硫除铜两段工艺研究了综合回收得到的高铜粗锑火法精炼除铜的反应机理 ,并确定了除铜的最佳条件。在略高于锑熔点温度 (6 5 0℃ )下 ,熔析可以除去粗锑中 90 %以上的铜 ,铜与砷形成Cu3 As、Cu5As2 化合物进入渣相 ,粗锑含砷量越高 ,熔析效果越好。加硫除铜反应由生锑与锑液间的扩散过程控制 ,通过改进加硫方式 ,能除去熔析后残余铜的 75 %。通过两段除铜 ,锑中铜含量降至 0 0 4 %。 相似文献
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随着科技的发展,钒应用领域不断地扩大,对钒产品纯度的要求也越来越高,所以对高纯度精钒制备技术的研究是很有必要的.磷是影响精钒质量的一种主要杂质,在石煤提钒过程中.钒酸钠溶液中的磷会与铵、钒形成复杂的络合物(杂多酸),当达到一定量时,影响五氧化二钒的质量,造成钒产品中磷含量超标.以石煤提钒过程的离子交换解析液为料液,主要针对石煤提钒离子交换工艺中磷的行为,提出了镁盐沉淀法从钒酸钠溶液中深度除磷,制备高纯V2O5的研究.分析了除磷过程中的机制,研究了镁盐加入量、pH、温度、时间等因素对除磷效果的影响.实验结果表明:在弱碱性条件下,镁盐法可有效除去钒酸钠溶液中的磷,除磷率达到96%以上,同时亦可有效除去钒酸钠溶液中的Si,Fe,As等杂质元素,最后V2O5的回收率达到94%以上.最佳除磷工艺条件为:温度45℃,净化时间50 min,镁盐加入量为原料液12%,pH=10.0.净后滤液在50℃加入铵盐沉钒,得到的偏钒酸铵在500℃下于马弗炉中煅烧2 h,最终得到的五氧化二钒产品质量达到99.9%以上. 相似文献
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本文在试验的基础上分析除镁剂的加入方式、除镁温度、保温时间、除镁制的加入量等工艺条件对除镁效果的影响,总结出最佳的除镁工艺。 相似文献
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研究了以臭氧和氟化钠为脱杂试剂,采用"溶解造液--强氧化除铁钴--氟化除钙镁--结晶析出"为主干的工艺处理粗硫酸镍,深度脱除其中的铁、钴、钙、镁杂质的工艺可行性及最佳工艺条件。试验结果表明,以臭氧为强氧化剂,可深度脱除粗硫酸镍中的铁钴杂质,最佳反应条件为:反应温度80℃,时间8h,终点pH值4.5~5.0,反应终点溶液中铁、钴浓度小于0.005g/L;以氟化钠做添加剂,可深度脱除粗硫酸镍中的钙镁杂质,最佳反应条件为:反应温度90℃,时间2h,pH值5.5,氟化钠添加系数1.5,反应终点溶液中钙0.007g/L,镁0.005g/L;将"强氧化除铁钴"与"氟化钠除钙镁"工序相结合,可获得更好的除杂效果。 相似文献
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Xiaofei Guan Peter A. Zink Uday B. Pal Adam C. Powell 《Metallurgical and Materials Transactions B》2013,44(2):261-271
Pure magnesium was recycled from partially oxidized 50.5 wt pct Mg-Al scrap alloy and AZ91 Mg alloy (9 wt pct Al, 1 wt pct Zn). Refining experiments were performed using a eutectic mixture of MgF2-CaF2 molten salt (flux). During the experiments, potentiodynamic scans were performed to determine the electrorefining potentials for magnesium dissolution and magnesium bubble nucleation in the flux. The measured electrorefining potential for magnesium bubble nucleation increased over time as the magnesium content inside the magnesium alloy decreased. Potentiostatic holds and electrochemical impedance spectroscopy were employed to measure the electronic and ionic resistances of the flux. The electronic resistivity of the flux varied inversely with the magnesium solubility. Up to 100 pct of the magnesium was refined from the Mg-Al scrap alloy by dissolving magnesium and its oxide into the flux followed by argon-assisted evaporation of dissolved magnesium and subsequently condensing the magnesium vapor. Solid oxide membrane electrolysis was also employed in the system to enable additional magnesium recovery from magnesium oxide in the partially oxidized Mg-Al scrap. In an experiment employing AZ91 Mg alloy, only the refining step was carried out. The calculated refining yield of magnesium from the AZ91 alloy was near 100 pct. 相似文献
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Eric S. Gratz Xiaofei Guan Jarrod D. Milshtein Uday B. Pal Adam C. Powell 《Metallurgical and Materials Transactions B》2014,45(4):1325-1336
The solid oxide membrane (SOM) process has been used at 1423 K to 1473 K (1150 °C to 1200 °C) to produce magnesium metal by the direct electrolysis of magnesium oxide. MgO is dissolved in a molten MgF2-CaF2 ionic flux. An oxygen-ion-conducting membrane, made from yttria-stabilized zirconia (YSZ), separates the cathode and the flux from the anode. During electrolysis, magnesium ions are reduced at the cathode, and Mg(g) is bubbled out of the flux into a separate condenser. The flux has a small solubility for magnesium metal which imparts electronic conductivity to the flux. The electronic conductivity decreases the process current efficiency and also degrades the YSZ membrane. Operating the electrolysis cell at low total pressures is shown to be an effective method of reducing the electronic conductivity of the flux. A two steel electrode method for measuring the electronic transference number in the flux was used to quantify the fraction of electronic current in the flux before and after SOM process operation. Potentiodynamic scans, potentiostatic electrolyses, and AC impedance spectroscopy were also used to characterize the SOM process under different operating conditions. 相似文献
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镁合金熔炼过程中的阻燃保护方法及进展 总被引:2,自引:0,他引:2
综述了镁合金熔炼过程中的熔剂保护、气体保护及合金化阻燃保护的研究现状及进展。熔剂保护和气体保护是目前国内外应用最为广泛的镁合金阻燃方法,但同时带来了环境污染等问题。研制经济、实用、无污染的镁合金熔炼保护方法将有利扩大镁合金的生产。 相似文献
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1. Calcium and magnesium movements in the isolated rabbit pancreas and in rabbit pancreas fragments are compared in a qualitative and quantitative way. 2. At the basal secretion rate calcium and magnesium are present in the secreted fluid in concentrations of about 30% of their concentrations in the bathing medium. 3. Addition of 10(-6) M carbachol to the bathing medium results in enzyme secretion accompanied by calcium and magnesium release, in divalent cation-free medium as well as in a complete medium. 4. The secretion of each divalent cation is the sum of two components: an extracellular flux and a flux of protein-associated cations, the so-called secretory flux. 5. The extracellular flux is proportional to the concentration of the divalent cation in the bathing medium. The secretory flux is not dependent on the presence of the divalent cation in the bathing medium, but is proportional to the amount of protein secreted. About 25 nmol of each cation is secreted per mg protein. 6. Ca2+ and Mg2+ can be nearly completely separated from the digestive enzymes by gel filtration. They equilibrate completely with their radioactive isotopes added to the sample just before elution, indicating that the cations are rapidly exchangeable after secretion. 7. Efflux studies on rabbit pancreas fragments, pre-loaded with 45Ca2+, show a carbachol-stimulated 45Ca2+ efflux (the stimulatory flux) in addition to a release of amylase. Fragments pre-loaded with 28Mg2+ do not show carbachol stimulation of the tracer efflux. 8. These studies indicate that calcium and magnesium behave quite similarly with respect to the extracellular and secretory fluxes. The absence of a stimulatory flux for magnesium, suggests that the increase of the cytoplasmic calcium concentration plays a specific role in the stimulus-secretion coupling of pancreatic enzyme secretion. 相似文献
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从含砷钼矿浸出液中脱砷 总被引:1,自引:0,他引:1
采用砷酸铵镁沉淀法对含砷钼矿的浸出液进行了脱砷研究。理论分析得到脱砷过程中浸出液pH=10、浓度为0.1moL/L时,溶液中砷浓度为3.2×10^-8mol/L。试验研究了pH值大小、NH4Cl、MgCl2用量对浸出液脱砷率、钼入渣率以及钼砷比(Mo/As)的影响。找到了脱砷的最佳试验条件,在该条件下砷的脱除率可达到99.71%;钼入渣率可降至2.36%;Mo/As可达8697.82,实现了含砷浸出液中砷的脱除。 相似文献
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用氟化锰脱除氯化锰溶液中的镁,考查溶液中的Mn浓度、Mg浓度、MnF2用量系数、PAM絮凝剂类型及用量、沉淀絮凝温度和沉淀时间等对沉降速率、渣过滤性能和除镁率等的影响。结果表明:只有当镁浓度≤3g/L时,才可顺利地去除镁,适宜条件为:MnF2用量系数1.1,非离子型PAM絮凝剂用量每克镁0.01~0.02g,沉淀絮凝温度80℃,沉淀时间60min。 相似文献
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惰气熔融法定量分析镁中气体含量必须结合合适的浴料/助熔剂,氧、氢和氮分别测定,才能有效地减少镁挥发物对分析结果的干扰,实现定量准确测定。应用特制的Sn-Ni-Fe-Cu-C五元浴测定纯镁粉、镁-铝粉、镁粒和镁锭样品中氧含量,相对标准偏差(RSD, n=3)小于31.5 %;用纯物质Mg(OH)2标定时,氧的回收率达97.1 %。应用锡助熔剂/浴料结合较低的分析功率测定纯镁粉、镁-铝粉和镁锭中氢,相对标准偏差(RSD, n=6)小于35.7%,采用Mg(OH)2标定,氢的回收率达96.9 %。应用镍助熔剂测定纯镁粉、镁-铝粉和镁锭中氮,相对标准偏差(RSD, n=3)小于23.6%,采用纯物质 Mg3N2标定,氮的回收率达99.2 %。应用钢标样监控镁污染情况,确保镁中气体分析数据的可靠性。 相似文献
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根据某湿法炼锌厂的原料特点,在大量试验工作的基础上,提出一条行之有效的工艺流程来解决杂质镁对系统的影响,它易于和现有生产系统相结合,易于实现工业化。 相似文献