MgO在氯化镁电解过程中的电泳行为

采用ＭｇＣｌ２－ＮａＣｌ－ＫＣｌ溶盐体系进行氯化镁的电解,在电解实验的基础上,研究了ＭｇＯ在电解过程中的电泳行为。通过对阴极钢板的表面ＳＥＭ分析和Ｘ射线衍射分析,表明阴极钢板上有氧化镁的存在时,部分阴极钢板表面出现“鱼子”状的金属镁。通过对ＭｇＯ杂质产生原因的分析,提出了减少ＭｇＯ杂质产生的措施。     

由过烧菱镁矿制取无水氯化镁

通过实验室加炭氯化试验结果表明,尽管菱镁矿经过烧后化学活性大幅下降,但对氯化反应速率影响不大。使用过烧菱镁矿作为氯化炉原料可保证料层均匀、透气性良好,从而有效利用炉内反应空间,提高氯化炉产能。     

由水镁石制取电解镁原料无水氯化镁

本文对我国某地水镁石的理化性能检验结果用实验室加炭氯化试验结果进行了论述，指出了该水镁石是优良的无水氯化镁生产原料。将其结果与目前我国使用的菱镁矿比较得知，该水镁石的理化性能较优，氯化反应速率较大。     

氯化镁电解整流系统的研究与设计

根据氯化镁电解多级槽的特性及要求,以设计的科学性和节能性为出发点,通过深入探讨镁电解整流系统的方案选择和设计方法,推出了科学合理的节能型解决方案。     

钾光卤石沸腾炉脱水的研究

钾光卤石沸腾炉脱水是钾光卤石炼镁过程的重要环节，通过双室沸腾炉脱水试验确定的脱水工艺和设备参数，成功地应用于工业规模试验装置，获得的技术经济指标可为建设镁厂提供依据，其中一些指标达到前苏联工业水平。     

论我国光卤石一次脱水现状及发展方向

论述了光卤石一次脱水过程以及我国在这方面发展过程和现状。提出了光卤石在ＨＣｌ气氛下沸腾脱水制得无水光卤石颗粒直接电解生产金属镁的工艺流程，此流程污染小，能耗低，易操作适合我国镁工业的发展。     

含碱式氯化镁光卤石电解的特点

当光卤石脱水和熔化时,氯化镁部分地发生水解,即使熔化是在氯化氢气氛中进行,在光卤石在氯化器中产生水解也是不可避免的,因为碱式氯化镁是水解产品之一,它在光卤石中生成固溶体。在700～800℃时,光卤石熔     

杂质对镁电解过程的影响及除去杂质的方法

文中叙述了杂质ＳＯ＾＋４,Ｈ２Ｏ,Ｂ,Ｃ,Ｆｅ,ＭｇＯ等的来源,对电解过程的影响,从而揭示这些杂质在原料,半成品及电解质中的允许含量,并简述除去这些杂质的方法。     

氯化镁电解时改善液镁阴极析出状态的途径

研究了氯化镁电解时液镁析出成相过程的机理和不同因素对液镁析出状态的影响。液镁析出过程是瞬时成核半球状三维生长过程。提高电流密度、提高电解温度和降低电解质中氯化镁浓度均能使液镁析出状态得到改善。利用反向电解技术进一步研究表明,镁的电流效率与液镁析出状态、液镁溶解速度和碱金属的析出有关。综合考虑,氯化镁电解宜采用尽可能低的MgCl_2浓度,适当高的电流密度和电解温度,以改善镁的析出状态,提高电流效率。     

Corrosion rate of magnesium and its alloys in buffered chloride solutions

The effect of the buffer capacity of test solution on the corrosion rate of cast pure (>99.95 mass%) and high-purity (>99.9999 mass%) magnesium, and AZ31 and AZ91E has been studied. Their corrosion rates were measured gravimetrically in a pH 6.5 and a pH 9 borate buffer including chloride ions, and in a conventional chloride solution. Except for the AZ91E in the pH 6.5, the corrosion rates of all the examined materials depended solely on the pH of the test solution, although the materials had a variety of purity and alloying elements. Higher buffer capacity probably masked the detrimental effect of the “cathodic impurities”. The corrosion rates measured in the buffers were considered as giving the resistivity of the passive film to anodic reactions. The high-purity magnesium had a fair corrosion resistance even in conventional chloride solution.     

The corrosion of steel and aluminium in calcium chloride/ammonia,magnesium chloride/methylamine and magnesium chloride/methylamine/decane

The corrosion of St 37, StE 36, Al 99,5 and Al-Mg 3 in the chemical pairs of substances calcium chloride/ammonia, magnesium chloride/methylamine and magnesium chloride/methylamine/decane was investigated. The corrosion tests were performed in autoclaves at room temperature to 180 °C. The nominal duration of the experiments was 1000 hours. Rod shaped fatigue specimens with polished surfaces served as test specimens; these were fatigue tested after the corrosion treatments. All materials tested were compatible with calcium chloride/ammonia under the experimental conditions employed. Steel and aluminium showed similar behaviour against magnesium chloride/methylamine and magnesiumchloride/methylamine/decane, respectively. At room temperature and 70°C to 80°C the corrosion of steel and aluminium was low (wall losses in the order of 1 m?m/a). Corrosion increased with increasing temperature. The activation energy for the reaction, which determined the rate of weight loss in magnesium chloride/methylamine/decane, was AE_st = 0, 60 ± 0,18 eV for steel, and AE_Al = 1, 07 ± 0,07 eV for aluminium. A corrosion treatment on aluminum fatigue specimens after 1000-1500 hours at 110 °C caused a notable decrease in fatigue strength; no such behaviour was noted for steel, even when corroded at 170 °C.     

The magnesium chloride-potassium chloride phase diagram

The MgCl ₂- KCl binary phase diagram has been redetermined experimentally by cooling curve analysis. It has three eutectics— at 427 °C (31 mol% MgCl₂), at 426 °C (35 mol% MgCh), and at 470 °C (57 mol% MgCl₂)— and two congruently melting compounds— K₂MgCl₄ at 428 °C (33 mol% MgCl₂) and KMgCl₃ at 488.5 °C (50 mol% MgCl₂). Aperitecticof K₃Mg2Cl₇ was found at 440 °C (36 mol % MgCl₂). Another phase change, for which we have not been able to offer a satisfactory explanation, was found at 424 °C in the 40 to 50 mol% MgCl₂ region. West Instruments, Mark IV Instruments Ltd., The Hyde, Brighton, E. Sussex, BN2 4JU, UK; or East Greenwich, RI02818-0962, USA.     

Solubility of chloride in molten magnesium metal

The solubilities of chloride (Cl) in liquid magnesium (Mg) have been determined from the analysis of quenched samples of liquid Mg equilibrated with NaCl-MgCl₂ melts of different compositions at temperatures in the range 650–790 °C. As an example, the solubility of Cl in liquid Mg in contact with pure MgCl₂ at 735 °C was found to be approximately 18 ppm. The Cl solubility was found to be proportional to the square root of the MgCl₂ activity in the NaCl-MgCl₂ melt, indicating that MgCl₂ dissolved according to the reaction 0.5MgCl₂ + 0.5Mg(l) = MgCl (in Mg). The temperature dependency of the solubility also was measured. Thermodynamic values related to the dissolution of MgCl₂ in liquid Mg have been estimated.     

隐钾锰型水合MnO_2的合成及其离子交换选择性

以硫酸锰和高锰酸钾为原料 ,合成了离子记忆无机离子交换剂—隐钾锰型水合二氧化锰 (CRYMO)。通过粉末X射线衍射以及热重分析确证了其晶体结构为α MnO2 ,化学式为MnO2 ·0 .4H2 O。考察了其对Na ,K ,Rb 的表观离子交换容量随溶液pH值的变化情况 ;离子交换等温线及分配系数曲线均表明隐钾锰型水合二氧化锰对K 和Rb 具有高选择性     

钛冶炼氯化镁氨法制备氢氧化镁研究

以某钛冶炼厂中间产品氯化镁为原料,进行了氨法制备氢氧化镁的研究。通过单因素试验及正交试验得到了较合适的工艺条件,所得氢氧化镁符合HG/T3607-2000 I级标准。但由于氨法存在收率低及生产过程不环保,该法仅适于大型建厂来处理大批量的氯化镁,对于处理钛冶炼不定量的氯化镁并不适用。     

碱式氯化镁晶须的水热制备及热分解机理研究

采用水热法以氯化镁溶液、氢氧化钠为原料制备了碱式氯化镁晶须。通过SEM和SAED观察样品的显微形貌及晶体结构,晶须长度150μm以上,直径0.5~1μm,为单晶物质。通过XRD测定样品的晶相结构,产物为碱式氯化镁9Mg(OH)_2·MgCl_2·5H_2O。通过红外光谱考察了不同镁离子浓度产物官能团的不同。升温速率为2~5℃/min,高温程序煅烧前驱体碱式氯化镁,制备出氧化镁晶须,很好的保持了碱式氯化镁晶须的形貌,仍为单晶物质,并推测了其可能的热分解的机理过程。     

Corrosion of magnesium and its alloys

Any detailed study of the corrosion of magnesium and its alloys in aqueous environment, must consider the three important aspects: galvanic corrosion reaction between magnesium and another metal, microgalvanic corrosion reaction between magnesium and the secondary phases or impurity grains, and the negative difference effect (NDE). In this paper, we propose a mathematical model to describe microgalvanic corrosion. We also discuss the NDE based on Tafel type kinetics and explain the NDE behavior in a consistent manner.     

The effect of molybdate anion on the ion-selectivity of hydrous ferric oxide films in chloride solutions

The ion-selective property of hydrous ferric oxide precipitate films has been investigated by measuring membrane potentials which arise across precipitate membranes of hydrous ferric oxide with and without adsorbed MoO₄^2? ions and of ferric molybdate in solutions of NaCl, KCl, MgCl₂, CaCl₂, BaCl₂, AlCl₃, and FeCl₃. The hydrous ferric oxide membrane was only permeable to Cl^? ions in chloride solutions, whereas the membrane with adsorbed MoO₄^2? ions was permeable to cations in NaCl and KCl solutions, and to both Cl^? and cations in the presence of multivalent cations. The ferric molybdate membrane was permeable to Cl^? and cations in NaCl and KCl solutions, and only to Cl^? ions in the presence of multivalent cations. It is suggested that in chloride solutions, the corrosion of iron covered with a precipitate film of hydrous ferric oxide is accelerated by enrichment of Cl^? ions under the film, which may decrease the local pH and introduce a positive diffusion potential in the film. The adsorption of MoO₄^2? ions on the oxide changes the ion-selectivity of the precipitate film from the anion-selective to the cation-selective in solutions of NaCl and KCl. This cation-selectivity of the film may inhibit the corrosion of iron, because of H⁺ ions diffusing out of the film. The inhibitive effect of MoO₄^2? ions would be reduced in the presence of multivalent cations.