Vacuum distillation refining of crude lithium （ Ⅱ）——Kinetics on vacuum distillation of crude lithium

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Thermodynamics of removing impurities from crude lead by vacuum distillation refining

A novel technique was developed to remove impurities from crude lead by vacuum distillation. The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of main components of crude lead, separation coefficients and vapor-liquid equilibrium composition of Pb-i (i stands for an impurity) system at different temperatures. The behaviors of impurities in the vacuum distillation refining process were investigated. The results show that the vacuum distillation should be taken to obtain lead from crude lead, in which Zn, As and partial Sb are volatilized at lower temperature of 923-1023 K. Lead is distilled from the residue containing Cu, Sn, Ag and Bi at higher temperature of 1323-1423 K, but the impurity Bi is also volatilized along with lead and cannot be separated from lead.     

一种RH新型离合式真空加料系统的开发与应用

钢液成分控制是RH真空处理过程中除脱气、脱碳、脱氧等功能外的一项重要功能.目前,固定式上、下料仓组合投料系统容易在长期频繁投料后密封性下降,经常造成钢液合金成分失控、真空投料能力下降、真空泵抽气时间延长等缺陷,严重影响了真空精炼的效率和品质.另外,这种投料系统的密封结构不易检修与维护,增大了漏料和漏气的可能性.为了严格控制钢液成分,生产出高质量、高附加值的精品钢和特种钢,中国重型机械研究院股份公司研究并开发了一种密封性、准确性、快速性和维护性良好的新型离合式真空加料装置,已应用于国外汽车板RH精炼项目中,取得了令客户满意的效果.     

新钢回收转炉余热蒸汽在真空精炼中的应用

针对转炉炼钢产生的蒸汽利用率低,及环保和能源浪费的问题,新余钢铁公司将转炉冶炼产生的高温蒸汽收集,存储于蓄热器,成功地将其做为RH精炼炉真空泵的动力源,对节能减排有重要意义.     

粗锑电解精炼除铋

针对粗锑精炼过程中锑铋难以分离的技术难点,采用H2SO4-NH4F-SbF3电解液体系进行高铋粗锑电解精炼除铋,考察温度、电流密度及添加剂对除铋的影响.通过扫描电镜(SEM)分析,研究添加剂对阴极锑沉积形貌的影响.获得水溶液电解精炼除铋的最佳工艺条件为:室温(25 ℃),电流密度为400 A/m2,异极距为50 mm,草酸加入量为10 g/L,电解周期为24 h.实验结果表明,锑电结晶按螺旋位错生长机理进行,其晶体呈三角棱锥结构;当草酸含量在适当范围之内时,锑镀层的生长机理无明显变化.     

分子相互作用体积模型在真空蒸馏分离铅-锡-锑三元合金中的应用

基于分子相互作用体积模型(MIVM),计算Pb?Sn?Sb三元合金体系的活度,并使用活度系数计算真空蒸馏过程中Pb?Sn?Sb三元合金体系的气液相平衡。结果表明：随着蒸馏温度和液相中锡含量的增加,气相中锡含量也不断增加;然而,在1100°C液相中锡含量为97%(质量分数)时,气相中锡含量仅为0.45%,分离效果较好。在真空(10 Pa)条件下,在1100~1300°C蒸馏温度范围内进行真空蒸馏分离Pb?Sn?Sb三元合金实验。结果表明：在1100°C时,当液相中锡含量为97%时,气相中锡含量为0.54%。最后对比分析了实验结果和预测值,分析表明实验结果和预测值吻合较好。     

Preparation of high-purity tantalum ethoxide by vacuum distillation

Effects of reflux ratio, water addition and content of water in ethanol on the purity and yield of tantalum ethoxide during vacuum distillation were investigated under the operational conditions of pressure of 1kPa, oil bath temperature of 210-230 ℃, and outlet temperature of 190℃. The condensate sample was characterized by FTIR, 1↑H-NMR spectroscopy and Raman spectra, respectively. The contents of tantalum, carbon and hydrogen in the sample were also determined with elemental analysis instrument. The obtained results consistently demonstrate that the condensate is tantalum ethoxide. The content of impurity, such as Al, As, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sn, Ti, V and Zn, in tantalum ethoxide is less than 0.000 05%, while Nb content is less than 0.000 5%. The content of impurities in tantalum ethoxide sample excels that of Epichem Group＇s requirement for Ta（OC2H5）5 of 99.999%.     

Preparation of high-purity bismuth by sulphur deleadization in vacuum distillation

The feasibility of separation of impurities in refined bismuth and sulphur deleadization with vacuum distillation was studied theoretically. Experimental studies on sulphur deleadization were carried out under vacuum. The influences of amount of sulphur, distillation temperature, vacuum degree and distillation time on deleadization were investigated and an optimal technical condition was achieved. The content of lead in refined bismuth can be decreased from 30μg/g to 0.21 μg/g, which has reached the level of“5N” high-purity bismuth. Other impurities in refined bismuth can be also removed effectively under certain conditions.     

Control of corrosion of carbon steel in crude oil distillation units

Abstract

Experiments were conducted to investigate the behaviour of different concentrations of 3–amino–1,2,4–triazole (ATR), 2–amino-thiazole (ATH), and 2,6–diamino-pyridine (DAP) as corrosion inhibitors for carbon steel exposed to a kerosene-water mixture containing 3ppm HCl and 800ppmH₂S/day at 55–60°C and pH 6–6·5 with different exposure times, using ammonia as a neutralising agent. Screening tests over,a period of 50 h showed that the presence of 10ppm of the compounds (ATR, ATH, and DAP) with ammonia as a neutralising agent in the absence and in the presence of 10ppm octylamine gave good inhibitor efficiencies (～90%). After 400 h of exposure the inhibitor efficiencies ranged between 50–75% depending on the material added to the test solution. XPS studies of the layer formed on the carbon steel surface indicate the formation of Fe(II) and Fe(III) complexes with the organic compounds used.     

北满特钢40t-LFV精炼炉真空系统改造

简要介绍了西安重型机械研究所为北满特钢一电炉分厂原有 40 t-LFV设备真空系统进行改造的具体内容。改造后其真空系统不仅能满足不同钢种精炼工艺的要求 ,且真空系统的能耗指标达到世界先进水平     

Impurity distribution in distillate of terbium metal during vacuum distillation purification

The distribution rules of impurities in distilled terbium metal were investigated by vacuum distillation purification experiment and theoretical analysis. It is found that Ti impurity in distilled terbium is 220 mg/kg in the initial stage of the distillation purification, increases slowly in the middle stage, and increases rapidly in the last stage, reaching 2260 mg/kg, and the modified separation coefficient of Ti is 1/19.02. The diffusion of the impurity Ti in liquid metal can reach a quasi-equilibrium state in the initial stage of distillation purification and the calculated results agree well with experimental results; the distribution profile of impurity Cu is opposite to Ti, being 380 mg/kg in the initial stage, decreasing linearly to 290 mg/kg in the last stage, and the modified separation coefficient is 17.99, and the theoretical calculated results are inconsistent with the experimental result.     

真空蒸馏Zn-Ni二元合金气−液相平衡研究

在系统压力5～10 Pa、蒸馏温度1173～1423 K条件下,开展Zn-Ni二元合金真空蒸馏实验研究.结果表明:液相中Ni含量(质量分数)由18.21％增至96.05％时,气相中的Zn含量由0增至99.9966％,并且通过实验获得真空蒸馏中Zn-Ni二元合金的气?液平衡(Vapor-liquid equilibriu...     

分子相互作用体积模型在真空蒸馏分离Pb-Sb、Pb-Ag和Sb-Cu合金中的应用

基于分子相互作用体积模型(MIVM),使用牛顿迭代方法结合无限稀活度系数实验数据γ∞计算对势能相互作用参数Bij和Bji;然后使用参数Bij和Bji计算Pb-Sb、Pb-Ag及Sb-Cu二元合金体系的活度α和活度系数γ,并与实验值进行比较分析;最后计算Pb-Sb、Pb-Ag及Sb-Cu二元合金体系的气液相平衡组成。气液相平衡组成计算结果表明:活度计算值和实验值吻合较好;Pb-Ag和Sb-Cu体系中的组元均能通过真空蒸馏实现良好分离,而Pb-Sb体系中的组元不能通过一次真空蒸馏实现完全分离。分子相互作用体积模型用于预测二元合金体系的活度及真空蒸馏分离效果具有很高的可靠性,为真空蒸馏分离二元合金提供良好的理论依据。     

铅锡合金的真空蒸馏深度脱铅(英文)

采用分子相互作用体积模型计算在777℃时不同Pb含量铅锡合金的活度系数,结果与实验值符合较好。对800～1300℃全成分范围内铅锡合金的活度系数进行预测,为铅锡金真空蒸馏分离提供必要的热力学参数。对两种不同铅含量的铅锡合金进行小型和工业实验,将锡中的铅含量降至0.01%以下。设计全成分范围的铅锡合金真空蒸馏处理流程,对铅含量10%～90%的铅锡合金经真空蒸馏处理后可得到纯度为99.5%的粗铅和铅含量在0.01%以下的精锡。     

Denitrogenation and desulphurization during vacuum induction melting refining Ni-base superalloy

The denitrogenation and desulphurization behavior during vacuum induction melting (VIM) refining Nibasesuperalloy using C.aO crucible was studied. It has been found that the desulphurization process did not occur by only using CaO crucible. Combining with the results of XRD and composition analysis, the desulphurization mechanism of CaO crucible was proposed. AI addition limits effect on denitrogenation, but it is very important for desulphurization. Ti addition has adverse effect on denitrogenation. The increase of vacuum is a powerful measurement to accelerate the denitrogenation process.     

粗金粉中金的氯浸-控制电位还原精炼

某冶炼厂氰化金泥还原得到的粗金产品纯度较低,采用氯浸-还原工艺对粗金进行了精炼提纯。在生产工艺中采用盐酸+氯酸钠对粗金进行氯浸溶解,用焦亚硫酸钠控制电位选择性还原浸出液中的金。采用补水-冷却使银和铅从氯浸液充分沉淀析出,通过调整pH值、改变焦亚硫酸钠添加方式、精确控制还原电位等方法,产品金锭达到IC-Au99.99标准。两年的生产实践创造了明显的经济效益。     

提高VD炉真空系统工作稳定性的研究

本文介绍了安钢VD炉真空系统的原理和相关参数,针对VD炉真空系统出现的工作真空度太低或系统的抽气时间过长问题,分析了故障产生的原因是真空系统内积水、积灰、泄漏及受冷凝水的压力和温度的影响,并采取了排水、除灰、调节冷凝水的压力和温度等措施.通过一年的生产实践,证明真空系统的稳定性得到提高,产品质量也大大提高,突发故障率降低80％.     

RH真空精炼脱碳模型参数辨识及应用

阐述了RH真空处理脱碳原理和真空脱碳算法,分析了表观脱碳速率的影响因素,针对影响因素具有多样性、复杂性和不确定性的特点,结合实际生产和经验数据,采用RBF神经元网络建立表观脱碳速率模型,在实际生产中通过该模型提高了真空处理脱碳模型预测精度.     

工业硅真空感应精炼过程数值模拟

用Multi-physics Comsol软件对工业硅真空感应精炼过程的温度场进行了二维数值模拟和分析,定量研究了精炼过程熔池中温度场动态分布特征.结果表明:精炼过程中熔池中存在不均匀的温度场,温度梯度随时间和空间位置发生变化,在保温阶段熔池底部和表面温差最大值为382 K.精炼过程中硅料熔化前后的温度分布明显不同,硅料熔化后电磁搅拌形成的热流场和熔池表面向外的热辐射对精炼过程熔池中温度分布产生了重要影响.     

Further experiments on the control of corrosion of mild steel in crude oil distillation

A still continuously refluxing kerosine and water with the addition of 3 ppm HCl and 800 ppm H₂S was used to test the effect of 8 compounds upon the corrosion of mild steel over 1000 h. The organic inhibitors used included triazoles, thiones, hydrazides and a chlorochalcone. The most effective inhibitors over the temperature range investigated (50–180°C) were the hydrazides and the chlorochalcone. Other compounds were found to be reasonably effective at 50°C, but they became less effective as the temperature was increased.