基于实践经验的锌液铝含量预测方法

锌锅中锌液铝含量决定了镀层的结构以及锌锅锌浴行为,热镀锌工艺要求锌液成分稳定控制。利用工业大生产的数据,建立一套铝消耗的经验模型。镀层中的铝含量主要由抑制层厚度决定,抑制层厚度取决于带钢运行速度。镀锌面积决定了锌渣发生量。根据锌锅铝物质平衡,利用已有的生产实绩包括锌锭添加量、镀层带走的铝量以及锌渣发生量等,测算出锌渣铝含量。应用本铝消耗经验模型,可预测锌液铝含量,也为稳定锌液成分的锌锭添加制度做准备。     

降低锌锭消耗的生产实践

基于锌液与带钢之间的反应机理,通过控制锌液中铝含量及锌液温度、规范锌锅捞渣方法、优化气刀设备与气刀参数等措施,在保证镀层质量的前提下,有效地控制了锌的消耗量.经过阶段性的生产实践,鞍钢天铁镀锌机组的月均锌锭消耗苗较前期降低了 14.8％,取得了良好的经济效益.     

钢丝镀锌层合金化的工艺研究

一、前言钢丝的镀锌层一般由纯锌层和合金层组成。纯锌层的厚度与镀锌速度和擦拭方式有关,而合金层的厚度与锌液温度,浸锌时间以及锌液中铝含量有直接关系,一般垂直引出的钢丝镀锌层以纯锌层为主,合金层较薄。合金层主要以ζ相为主,由于ζ相为单斜晶体,因此塑性差。通常为了得到柔韧而有塑性的     

热镀锌钢板生产概述 第四讲 锌液中加铝对镀锌的影响及热镀锌理论的发展

锌液中加入少量的铝,可以形成保护性氧化膜,而大大减少锌液表面的氧化。试验可知,在钢板浸入锌液后,锌液中的铝富集在钢板表面上,形成中间层Ｆｅ２Ａｌ５,Ｆｅ２Ａｌ５改善了锌液与钢铁的附着力,从而提高了镀锌产品的机械性能。介绍了这一理论的发展过程。     

热镀锌钢板生产概述

锌液中加入量的铝,可以形成保护性氧化膜,而大大减少锌液表面的氧化。试验可知,在钢板浸入锌液后,锌液中的铝富集在钢板表面上,形成中间层Ｆｅ２Ａｌ５,Ｆｅ２Ａｌ５改善了锌液与钢铁的附着力,从而提高了镀锌产品的机械性能。介绍了这一理论的发展过程。     

生产优标镀锌管的技术措施

为使镀锌管达到优标 YB(T)31—86的要求,增加经济效益,鞍钢焊管厂采取了以下技术措施:增加镀锌层中δ_1相层的厚度,使之形成完全的镀锌层;严格控制锌液温度在450～470℃之间,浸渍时间20～30s;锌液铁含量0.02％以下,铝、锡、锑0.1％以下,不使用含铜高的锌;严格控制酸洗质量。结果使镀锌管全部达到优质优价的要求,进入国际先进行列。     

改善波形梁钢护栏表面涂层均匀性的方法探讨

影响热镀锌层均匀性的主要因素是锌液中的铝含量和吹拭工艺。在锌液中加入适当的铝元素,可以明显改善锌液的流动性,提高镀锌层表面光洁度,从而达到提高镀锌层均匀性、降低锌消耗的目的。将内吹环的结构形式由点状改为环状,使其吹拭力分布更加均匀,也有利于镀锌层的均匀性。锌层厚度在39～50μm,平均锌层厚度45μm,锌层散差值小于11μm。选择室温-中温磷化前处理工艺,确定磷化液优化配方参数;采用10把外带电静电喷枪对称布置,优化了静电场分布、压缩空气压力、环境温湿度、日常维护、操作技能等。根据聚酯粉末的特点,优化了聚酯粉末的配方和粒径,重点是改善边角处涂层的均匀性。塑层厚度在76～109μm,平均塑层厚度89μm,散差值小于33μm。按照改善后的方法生产出的产品,均符合GB/T31439.1-2015《波形梁钢护栏》的要求。     

连续热镀锌机组锌液出渣原因分析及控制对策

文章分析了包钢连续热镀锌机组中影响锌液出渣率的各种因素,制定了相应的对策以控制锌液出渣率,从而降低镀锌卷的生产成本,提高镀锌卷的质量。     

邯钢冷轧厂热镀锌渣形成原因分析及控制措施

在热镀锌生产过程中,热镀锌渣的产生不可避免,不仅造成大量锌消耗的急剧增加,而且还会影响产品质量。通过对热镀锌渣生长机制、形成原因进行分析,结合邯钢实际提出了减少锌渣的控制措施及建议。锌锅中锌液铝质量分数控制在0.2%~0.3%,锌液温度波动范围为460~466℃,带钢温度维持在440~480℃。生产线速度控制在70~100m/min。通过合理优化镀锌工艺,有效减少了锌渣的生成量,节约了原材料的消耗,降低了生产成本,对改善产品质量具有重要的指导意义,可操作性较强。     

热浸镀Galvalume熔池中铝锌渣的形态及分布

通过对生产状态和静置状态下Galvalume熔池面层、中间层和底层的含渣铝锌液的研究,结果表明在生产状态时铝锌液中铁含量较高,面层和中间层铝锌渣差异不明显。静置铝锌熔池面层基本不含铝锌渣,但中间层出现的铝锌渣相对生产状态时渣粒平均直径要大,铝锌渣析出长大使得铝锌液中的铁含量降低。在铝锌池底部存在大量的铝锌渣,且铝锌渣随着时间的延长不断积聚长大。通过成分分析确定该铝锌渣相为含锌的τ5C相。     

锌在新型低温熔盐中的绿色电沉积

合成、表征了氯化胆碱/尿素型低温熔盐,以此为溶剂研究了氧化锌在其中的溶解过程、离子组成、以及锌的电化学还原反应规律,分析了温度、电位、离子浓度对锌沉积物的形貌、晶型和纯度的影响。研究表明,当溶液中Zn(Ⅱ)的浓度为0.3~0.5mol/L时,可在313.2~343.2K、-0.3~-0.6V下获得平整、致密、均一的锌沉积层,此时其在铜基体上沿着(002)晶面优先生长。该技术不仅提高了锌镀层的质量和纯度,也有望扩展到锌精炼、锌合金和功能锌材料的制备等领域。     

LaCl3-KCl熔盐体系物化性质研究

合理选择熔盐体系在电解法制备稀土金属工业生产过程中至关重要。文中采用阿基米德法、拉筒法和连续变电导池常数法（CVCC）测定了不同配比的LaCl₃-KCl熔盐在1 073~1 223 K下的密度、界面张力和电导率。结果表明,随着温度升高,相同成分的LaCl₃-KCl熔盐的密度（ρ）和界面张力（σ）均呈降低趋势,而电导率（κ）逐渐增大;在相同温度下,随着LaCl₃含量增加,LaCl₃-KCl熔盐的密度和界面张力均逐渐增大,而电导率逐渐减小。通过拟合获得密度、界面张力以及电导率的经验公式分别为ρ=a-b×T×10-3、σ=a-b×T×10-3、κ=A+B×T×10-3+C×T2×10-6,明晰了熔盐的物化性质随温度及组分的变化规律,为熔盐电解法制备镧及其镧合金提供科学依据。      

Surface tension of zinc: The positive temperature coefficient

The positive temperature coefficient of the surface tension of molten zinc has been confirmed experimentally with a maximum-bubble-pressure (MBP) system. The possible effects of the high vapor pressure of molten zinc on the surface tension have been checked by making the measurements at atmospheric pressure and repeating at 1,800 Torr. The measurements were made on 99.999 pct zinc in the range from 436 to 806°C in an improved twin-tube MBP system. Results are that, over the given temperature range, the surface tension (γ) of zinc is given by γ (dynes/cm) = 839.7 − 125.7 e^−0.00941(T−419.5) The temperature (T) is in degrees centigrade. A total of 130 experimental values were determined with a correlation index of 0.98 with the equation. Comparisons of this result with others in the literature are discussed.     

Surface tension and wettability studies of liquid Fe-Ni-O alloys

Surface tensions of iron-nickel alloys were measured as a function of oxygen potential at 1550 °C using the sessile drop technique. The surface tension of pure liquid nickel and iron-nickel alloys was measured at a total pressure of 1 atmosphere under varying CO₂/CO ratios. An increase in the oxygen potential in the gas phase was found to correspond to a decrease in surface tension of pure nickel and iron-nickel alloys, indicating that oxygen is surface active in both liquid nickel and iron-nickel alloys. At low oxygen potentials, nickel additions to liquid iron were found to cause small decreases in alloy surface tensions; however, at higher oxygen potentials, the surface tension of the alloy exhibited a minimum value as nickel was added to iron. The adsorption coefficients of oxygen in liquid iron-nickel alloys and pure liquid nickel were determined from the surface-tension data using Belton’s analysis, and were found to be similar to those calculated from kinetic studies. Wettability of iron-nickel alloys on an alumina substrate was studied through contact-angle measurements. At a constant alloy nickel content, the contact angle between the alloy and alumina decreased with increased oxygen potential in the gas phase.     

非水溶剂电还原制取重稀土金属及合金的研究现状及发展

随着重稀土元素对铝、镁、铜、镍及钢铁等金属材料的功能化作用被广泛关注,使得作为战略性资源的重稀土元素在金属合金材料的应用领域拓展空间巨大.在此背景下,作为改性元素的重稀土金属及合金的市场需求必然猛增.由于重稀土单质自身的高熔点,混熔法、真空热还原法一直是生产制备重稀土金属及合金的主要方法,寻求一条低成本、高效、绿色的制备方法则至关重要.由于熔盐电化学还原法在生产低熔点轻稀土及合金工艺方面具有经济、高效等优势,近年来,通过熔盐电解方式直接制取低熔点的重稀土合金成为国内外学者研究的热点,从目前取得进展来看,具有广阔的发展前景.针对国内外重稀土金属及合金的熔盐电解法制取的研究现状进行了评述,从体系物理化学性质、电极过程机理、模拟计算等几个方面做了简要的总结和分析,以期对重稀土合金材料的制备研究提供有益的帮助.      

The production of nickel-zinc alloys by powder injection

Alloys of nickel and zinc are used for the hot dip galvanizing of reactive steels containing around 0.1 pct Si. The production of these alloys is hindered by the low solubility of nickel in molten zinc at normal zinc alloying temperatures (450 °C to 550 °C). The kinetics of the dissolution of nickel in molten zinc were investigated in the temperature range 450 °C to 550 °C to show that the dissolution rate is controlled by mass transfer in the liquid boundary layer. The experiments involved dipping nickel plates into a crucible of zinc, which could be rotated to provide controlled convection around the stationary nickel plates. The dissolution rate of nickel plates immersed vertically in a static zinc melt was measured to determine the diffusion coefficient of nickel in zinc as a function of temperature and the activation energy of diffusion. A mathematical model was formulated to predict the dissolution time of nickel particles suspended in molten zinc. The dissolution times observed during plant-scale alloying tests to produce 0.15 wt pct Ni alloys using powder injection to introduce the nickel into the zinc melt agreed with the predictions of the mathematical model. The plant tests demonstrated that alloying times of less than 10 minutes can be achieved at normal alloying temperatures if the nickel is added as a powder.     

锌基热镀合金的流动性能分析

采用金属型螺旋线试样测量纯锌及锌基热镀合金的流动性,以10℃为一个温度梯度,测量了420-510℃之间的流线长度数值。分析了液态金属流动性的影响因素,在锌液中加入0．3％（质量分数）的稀土合金,探讨了合金成分对流动性的影响。研究发现加入0．3％的稀土合金后,在相同温度下,合金的流动性比纯锌有明显提高。     

熔盐电解制备铝锂合金中阳极过程动力学参数的分析与计算

680℃下,在LiCl-LiF-KF体系中分别以LiCl和Li2CO3为原料电解制备铝锂合金,采用连续脉冲-计算机法测量阳极过电压并研究极化曲线的变化,根据电极过程动力学的理论计算并分析了CO2-3放电机理和反应速度控制步骤.研究表明：在电流密度为0.1-0.3 A·cm-2的Tafel区内,LiCl电解电极反应受电化学极化控制,Li2CO3电解电极反应受化学极化控制;电解Li2CO3时整个电极反应速率是由炭阳极上配合氧离子的缓慢放电引起的电化学控制步骤决定的.     

中间包微孔MgO耐火材料与钢液反应行为

为了评估新型中间包微孔MgO耐火材料与钢液的反应性,系统测定了不同钢液与微孔MgO耐火材料表观接触角,研究了界面化学反应产物以及钢中夹杂物组成的变化.结果 表明:含硫钢在微孔MgO耐火材料上铺展性最好,帘线钢次之,模具钢最差,主要是表面活性元素S降低了钢液表面张力所致;熔钢与耐火材料的界面行为中既包含了物理渗透又包含了...     

Carbothermic Reduction of Zinc and Iron Oxides in Electric Arc Furnace Dust

The reduction of zinc and iron oxides from electric arc furnace dust(EAFD)by carbon was investigated at temperatures between 800and 1 300℃.The analytic technique employed includes chemical analysis,X-ray fluorescence spectroscopy(XRF),X-ray powder diffraction(XRD),scanning electron microscopy(SEM)equipped with X-ray energy dispersive spectrometry(EDS),and thermodynamic database FactSage 6.2.It was found that the reduction of zinc and iron oxides depends largely on Boudouad reaction.At 900 ℃,zinc exists in tested samples as ZnO,which is reduced in the temperature range of 1 000-1 100℃.At 1 100℃,99.11% of the zinc is evaporated.The metallization ratio of Fe is 79.19% at 1 300℃,as the content of Fe2+ is still 9.40%.A higher temperature is thus required for a higher reduction degree of Fe oxides by solid or gaseous carbon.