铝土矿反浮选体系分散与凝聚理论

在铝土矿反浮选脱硅过程中,矿浆悬浮液的分散和凝聚状态对微细粒－水硬铝石的回收和精矿铝硅比有显著影响。要使各种硅酸盐矿物混合物达到有效的选择性分离,首先必需使矿浆悬浮液处于最佳分散状态,避免各种矿物细粒间的相互混杂和矿泥罩盖。针对高硅铝土矿反浮选脱硅过程,根据经典DLVO理论,从颗粒间的相互作用分析了微细粒－水硬铝石在各种含硅脉石矿物表面的粘附情况。结果表明：一水硬铝石与含硅脉石矿物颗粒间的范德化相互作用总是吸引;而它们间的静电相互作用在弱碱性条件下时为排斥,在弱酸性条件下时为吸引,一水硬铝石的夹带上浮较为严重,不利于铝土矿的反浮选。     

十二烷基胍对铝硅矿物的浮选分离

采用含有胍基的长碳链季铵盐作捕收剂,研究-水硬铝石、高岭石、叶腊石和伊利石单矿物的浮选行为、铝硅人工混合矿样的浮选分离以及河南铝土矿的精选.结果表明:在捕收剂用量为2×10-4mol/L条件下,在广泛的pH范围内,十二烷基胍对硅酸盐矿物具有较好的捕收能力,平均浮选回收率可达80%;强碱性条件下,一水硬铝石的浮选回收率从80%急剧下降至20%,与高岭石、叶腊石和伊利石之间形成较大差异:以十二烷基胍为捕收剂可望实现铝硅矿物反浮选分离:实际铝土矿(原矿铝硅比为5.70)经过反浮选脱硅,精矿铝硅比达11.08,铝浮选回收率为75%;与传统的阳离子捕收剂十二胺相比,胍类阳离子捕收剂对硅酸盐矿物浮选能力强、受pH的影响小,是一种新型高效的铝硅矿物浮选分离捕收剂.     

变性淀粉在铝硅矿物浮选分离中的作用机理

通过浮选实验、动电位和红外光谱测定,详细考察了变性淀粉在铝硅矿物浮选分离中的作用效果和机理。浮选实验显示：非离子淀粉和阴离子淀粉在pH＜6时,抑制一水硬铝石的浮选,但当pH＞6时,却对一水硬铝石浮选有活化作用;阳离子淀粉在较宽pH值范围内对一水硬铝石均有抑制作用;3种淀粉化合物在pH＜6时均活化高岭石的浮选,当pH＞6时活化作用较微。结果表明：变性淀粉是一水硬铝石型铝土矿反浮选中实现一水硬铝石和高岭石分离的有效调整剂,阴离子淀粉使矿物表面ζ电位更负,阳离子淀粉使矿物质表面ζ电位更正,非离子淀粉使矿物表面电位绝对值减小。由实验结果结合药剂与矿物作用前后的红外光谱分析,得出结论：非离子淀粉主要通过氢键作用吸附于矿物表面,而静电力和化学键合力在阴离子淀粉和阳离子淀粉吸附中发挥着重要作用。     

有机硅阳离子捕收剂和淀粉抑制剂分选铝土矿（英文）

以有机硅阳离子表面活性剂TAS101为捕收剂,淀粉为抑制剂,研究一水硬铝石和3种硅酸盐矿物高岭石、叶腊石和伊利石的浮选行为。结果表明,在pH值范围为4-10时,TAS101对一水硬铝石和3种硅酸盐矿物均有较强的捕收能力。在碱性pH条件下,淀粉对一水硬铝石有较强的抑制效果但不会影响硅酸盐矿物的浮选。使用淀粉作为抑制剂,TAS101作为捕收剂能够实现一水硬铝石和3种硅酸盐脉石的浮选分离。对铝土矿浮选闭路试验进行进一步研究,采用反浮选流程,使用淀粉作为抑制剂,TAS101作为捕收剂,在pH=11条件下进行浮选,当原矿Al_2O_3与SiO_2的质量比为6.1时,可以获得Al_2O_3与SiO_2的质量比为9.58,Al_2O_3回收率为83.34%的精矿。     

一水硬铝石型铝土矿铝硅浮选分离的溶液化学

分析了我国铝土矿中一水硬铝石和铝硅酸盐脉石矿物的晶体结构与表面性质,一水硬铝石与铝硅酸盐脉石矿物晶体结构的差异、表面断裂的Al-O和Si-O健及表面离子活性区的差别,可影响矿物表面的润滑性与可浮性,类质同象及各种晶格杂质离子也将影响浮选剂与矿物表面的相互作用和矿物可磨性,提出了正浮选、反浮吕硅分离的技术原型,用溶液化学与计算研究了其基本原理。结果表明,通过溶液化学计算可确定阴离子捕收剂正浮选脱硅时捕收剂,分散剂和PH三者之间的匹配关系,矿物的PZC与捕收剂的pKa值是阳离子捕收剂反浮选的主要控制参数,阴离子捕收剂反浮选时,铅盐和钙盐是浮选铝硅酸盐较理想的活化剂。     

新型Gemini阳离子捕收剂对一水硬铝石和高岭石的反浮选行为

研究了Gemini 12-4-12对一水硬铝石和高岭石的浮选行为,在中性介质(pH7～pH8)下,对一水硬铝石与高岭石的反浮选分离作了初步探讨.浮选结果表明:Gemini 12-4-12在广泛的pH范围内对一水硬铝石和高岭石具有很强的捕收能力,在中性体系(pH7～pH8)及浓度3.0×10~(-4)mol·1~(-1)时,对一水硬铝石和高峰石的浮选回收率达到95%以上;在可溶性淀粉浓度为200mg/l的条件下,一水硬铝石全部被抑制,而且两种矿物回收率相差达70%以上,并且通过人工混合矿试验,对不同A/S的一水硬铝石和高岭石人工混合矿取得很好的分离效果.     

极难选—水硬铝石型铝土矿反浮选脱硅的研究

为了解决细粒浮选的问题,本文作者采用一水硬铝石型铝土矿进行反浮选脱硅试验研究,并针对高硅型铝土矿首次提出了“强化二次富集”技术并将谈技术成功地应用于实际矿石的浮选,达到了反浮选脱硅的目的.针对一水硬铝石型铝土矿试验结果表明:通过“强化二次富集”技术的应用,在不预先脱除矿泥的情况下直接进行铝土矿的反浮选试验,最终获得了满意的精矿指标:精矿铝硅比10.28,Al2O3回收率85.41％.     

季铵型阳离子捕收剂在一水硬铝石和高岭石表面的吸附机理

研究十二烷基三甲基氯化铵（DTAC）和十六烷基三甲基氯化铵（CTAC）对一水硬铝石和高岭石的浮选行为。通过残余浓度法测定吸附等温线,荧光探针法和Zeta电位测试方法研究季铵型阳离子捕收剂在矿物表面的吸附机理。浮选结果表明：将DTAC和CTAC作为捕收剂,一水硬铝石的浮选回收率随着pH的增大而增加,而高岭石的浮选回收率随着pH的增大反而下降。当捕收剂的碳链增长时,矿物浮选回收率提高,但高岭石的增加幅度小于一水硬铝石的。在低浓度范围内,阳离子表面活性剂通过静电作用吸附在一水硬铝石表面,而对于高岭石,还存在离子交换作用。当浓度增大时,阳离子表面活性剂通过碳链间疏水缔合作用在两种矿物表面进一步吸附。矿物表面微极性研究表明：CTAC的疏水性比DTAC强,相同溶液浓度下CTAC在一水硬铝石表面能形成比在高岭石表面更大的胶团,这也说明阳离子表面活性剂碳链的增长对一水硬铝石吸附的影响要大,与浮选结果相吻合。     

油酸钠对一水硬铝石和高岭石的捕收机理

用油酸钠为捕收剂,研究了一水硬铝石和高岭石的可浮性,并对捕收剂与矿物的作用机理进行了探讨,结果表明：油酸钠对一水硬铝石和高岭石的捕收主要由两方面因素控制,在pH4-7范围内,为化学反应起主要作用,在pH7-10以形成离子-分子缔合物为主要因素,在以油酸钠为琢收剂时,矿物表面活性Al^3 数量的不同导致了高岭石和一水硬铝石的可浮性差异,这为铝土矿正浮选脱硅提供了理论依据。     

直链烷基胺浮选铝硅矿物机理

研究了一水硬铝石和高岭石、叶蜡石及伊利石等几种含铝硅酸盐矿物在不同pH条件下的动电行为与浮选行为。一水硬铝石、高岭石、叶蜡石及伊利石的等电点（IEP）分别为pH6．2,4．3,2．0,3．4。在pH＞IEP时,烷基胺类阳离子捕收剂主要以静电作用吸附在一水硬铝石矿物表面,其浮选高岭石等3种铝硅酸盐矿物的可浮性大小顺序是叶蜡石＞高岭石＞伊利石。高岭石、叶蜡石和伊利石均是层状硅酸盐矿物,其破碎磨细时,将沿层间断裂,由于晶体结构的原因其层面荷负电荷。烷基胺类阳离子捕收剂以静电作用力吸附于铝硅酸盐矿物表面的层面使矿物疏水上浮。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.