盐酸介质中Ce(NO_3)_3/CTAB复配对碳钢表面的缓蚀性能

采用失重法、电化学极化法、交流阻抗法和扫描电镜法研究了Ce(NO_3)_3/CTAB复配体系对碳钢的缓蚀性能,发现虽然Ce(NO_3)_3单组分对碳钢表面基本上没有缓蚀作用,但二者复配后仍能够达到CTAB单独使用的缓蚀能力,缓蚀效率达到90%以上,即使CTAB含量α1=0.1时,三种方法测试的缓蚀效果均为95%以上。说明在盐酸介质中Ce(NO_3)_3可以代替部分CTAB作为缓蚀剂,起到绿色环保的作用。     

硫酸介质中氯化镧与阴离子表面活性剂十二烷基苯磺酸钠(SBDS)对锌的缓蚀协同效应

用失重法研究了硫酸介质中稀土镧(Ⅲ)离子和阴离子表面活性剂十二烷基苯磺酸钠(SBDS)在硫酸介质中对锌的缓蚀协同效应.发现La3+在低浓度下有增蚀作用;SBDS对锌则有一定的缓蚀作用,但最大缓蚀率仅有35%.实验结果亦表明SBDS与La3+对锌表现出强烈的缓蚀协同效应.     

W-Ce复合缓蚀剂对X80管线钢的缓蚀性能及机理研究

为了研究Na_2WO_4·2H_2O、Ce(NO_3)_3·6H_2O单一缓蚀剂以及Na2WO_4·2H_2O-Ce(NO_3)_3·6H_2O(简写为:W-Ce)复合缓蚀剂对X80管线钢的缓蚀作用,采用失重法计算钢试样在不含和含有不同缓蚀剂的中性Na Cl介质中的缓蚀效率,结合SEM表征确定出,在35℃恒温条件下,780 mg·L~(-1)Na_2WO_4·2H_2O与660 mg·L~(-1)Ce(NO_3)_3·6H_2O复配得到的W-Ce复合缓蚀剂具有最高的缓蚀效率,达99.01%。根据EDS分析和多酸配合物的理论,探究了W-Ce复合缓蚀剂的缓蚀机理和模型。最终认为,W-Ce复合缓蚀剂对X80钢片的缓蚀作用,主要是通过Ce~(3+)和WO_4~(2-)形成的杂多酸[Ce(WO_4)_3]_n~(3-)与钢片表面的Fe配位吸附作用,形成一层缓蚀膜,从而隔绝腐蚀介质,产生了优良的抑制腐蚀效果。     

二氯二氨锌的制备及性质

以次氧化锌为原料,经氨浸、除铁、深度除杂、结晶等工序制备二氯二氨锌(Zn(NH3)2Cl2)。结果表明,在NH4Cl浓度4 mol/L、NH4Cl与Zn的摩尔比4∶1、浸出温度70℃、浸出时间60 min的条件下,Zn浸出率高达99%以上。采用质量分数为27.5%的双氧水氧化除铁和锌粉置换可基本彻底除杂。对二氯二氨锌进行了主含量、XRD、SEM、TG-DSC分析验证,结果表明二氯二氨锌的纯度较高,晶形完整。     

粗锌的络合物电解法精炼提纯

在以络合物Zn（NH3）2Cl2与NH4Cl溶液组成的体系中,以粗锌做阳极、铝片做阴极,根据锌与杂质元素标准电极电位的差异进行粗锌的电解精炼提纯．     

Ce~(3+)和钼酸钠对X80钢的缓蚀协同效应

为了研究稀土与钼酸盐之间的缓蚀协同效应,采用失重法和电化学法研究了盐酸介质中,Na2MoO4、Ce(NO3)3以及Na2MoO4-Ce(NO3)3复合缓蚀剂对X80管线钢的缓蚀作用。根据动电位极化曲线法计算了钢试样在不同的盐酸溶液中,发生溶解反应的动力学与热力学参数(表观活化能Ea、反应焓变ΔHa以及反应熵变ΔSa),证明了实现缓蚀反应的可能性和现实性,同时表明Na2MoO4-Ce(NO3)3复合缓蚀剂的存在使钢试样表面形成了一层更有序致密的薄膜,因此增大了钢试样发生溶解反应的表观活化能,降低了腐蚀速度。通过对比实验发现,Na2MoO4和Ce(NO3)3对X80管线钢产生了明显的协同缓蚀作用,且缓蚀效率及其相关参数受到温度变化的明显影响。     

锌焙砂氨法生产高纯锌

介绍了用NH3-NH3Cl水溶液浸出锌焙砂,制取高纯锌的新工艺,Zn的平均浸出率约93%,电锌含Zn＞99.999%,杂质元素Cu、Cd 、 Co 、Ni 、Fe 、As、Sb均小于0.0001%,Pb＜0.0003%.     

La、Ce掺杂对水热法合成镍锌铁氧体的影响

采用水热合成法制备镍锌铁氧体粉体,以稀土元素La、Ce进行掺杂,利用SEM和XRD 等手段对样品进行表征.结果表明,La3+、Ce3+掺杂后,La3+、Ce3+离子掺杂进入镍锌铁氧体晶格后,会产生一定的晶格畸变,造成晶粒常数的增大,但对晶体的形貌影响不大.除存在少量大颗粒,立方尖晶石相Ni0.35Zn0.65Fe1.9...     

锌焙砂氨法生产高纯锌

介绍了用NH3-NH4Cl水溶液浸出锌焙砂，制取高纯锌的新工艺，Zn的平均浸出率约93％，电锌含Zn＞99．999％，杂质元素Cu、Cd、Co、Ni、Fe、As、Sb均小于0．0001％，Pb＜0．0003％。     

苯并三氮唑和钨酸钠对铜的协同缓蚀效应研究

通过极化曲线和交流阻抗谱研究了苯并三氮唑(BTA)和钨酸钠(Na2WO4)对紫铜在5%Na Cl溶液中电化学行为的影响。研究表明,在5%Na Cl溶液中,BTA和Na2WO4单独使用均能够抑制铜电极的阳极极化和阴极极化,对铜的腐蚀具有阻碍作用。两者复配使用能够进一步增大电荷转移电阻,阻碍铜腐蚀电化学反应的电荷转移过程,抑制铜的溶解和氧在电极表面还原,显示出协同缓蚀效应。     

Effect of Al22Si/ZL102 bimetal interface fabricated by extrusion at near-eutectic temperature

The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared between the Al22Si and ZL102 bimetal.The average bonding strength of bimetal with intermittent oxide film interface was about 89.3 MPa, which is higher than that of the bimetal fabrica-ted by zinc coating method (about 76.3 MPa).During the process of extrusion, the oxidation film was extruded to crush and the metal was extruded through the micro-cracks of the oxidation film, then the two surfaces were joined together.Altogether, the results showed that extrusion at near-eutectic tem-perature is favorable for achieving a high-quality metallurgical bonded interface.     

还原气氛下温度对镀锌废钢脱锌的影响

通过火法脱锌试验及SEM、EDX和XRF等分析方法,研究了镀锌废钢在还原气氛条件下锌及基体的变化,从热力学角度探讨了脱锌机理。结果表明,低温时锌在钢基体表面形成较薄的氧化膜,厚度随温度上升而增加,明显的黄色氧化锌层在850 ℃以上形成,并在950 ℃消失;还原性气氛下950 ℃时脱锌效果最佳,表面锌质量分数小于2%;在火法脱锌过程,钢基体表面的锌经历了氧化、还原和气化脱除3个阶段。研究对于开发镀锌废钢的火法脱锌技术具有重要意义。     

Scanning auger microprobe study of hot-dipped regular-spangle galvanized steel: Part II. surface composition of chromated sheet

Zinc coatings produced on a hot-dipped-coating pilot line from a zinc bath containing small amounts of aluminum, antimony, and lead were treated with a commercial chromating solution and then examined with a scanning Auger microprobe. The results show that the chromating solution attacked the thin aluminum oxide precipitates in the zinc surface. The invisible conversion-coating film that was formed on the zinc matrix consisted mainly of oxygen, zinc, and chromium in order of decreasing atomic concentration. Surprisingly, the thickness and composition of the film was the same for treatment in 8 and 15 grams-per-liter chromate solutions. The film that was formed on precipitates of lead in the surface of the zinc coating was much thicker and richer in chromium than the film formed on the surrounding zinc. Examination of chromated surfaces exposed to water-saturated air at 100 °F and to normal atmospheres showed that the surfaces corroded rapidly on a microscale. After only a few hours exposure the surface had numerous mounds composed of equal atom concentrations of zinc and oxygen. In each instance corrosion sites were associated with a lead precipitate.     

焊剂在ZA合金TIG焊接过程中作用机理初探

因锌合金不易焊接,采用加入焊剂的方法对新型模用锌基合金(ZA合金)进行了TIG焊接。通过金相显微镜、X射线衍射等分析方法对焊接接头组织及焊后残渣采样进行分析,并对焊剂的作用机理进行了初步研究。结果表明:焊接过程中,焊缝表面形成大量氧化物;加入焊剂的主要作用是通过冶金反应清除焊接材料表面的氧化膜,同时向焊缝中过渡Zn。     

Effect of Manganese Content on Wetting Behavior of Low-Carbon Interstitial-Free Steel by Liquid Zinc

In this study, the effect of manganese content in the steel on the dynamic reactive wetting behavior of low-carbon IF (interstitial-free) steel by liquid zinc was investigated. The initial wetting behavior could be explained by the traditional wetting theory according to the Cassie equation. As the chemical reactions between liquid zinc and steel plate started, the surface oxide film on the steel plate prevented the chemical reactions by occupying the reaction sites.     

铝棒低银铅合金表面陶瓷化复合阳极的制备与性能

为获得一种锌电积用低成本、低析氧电位和高催化活性的阳极,在铝棒表面通过挤压复合技术包覆Pb-0.2% Ag合金得到Al棒Pb-0.2% Ag阳极.在含氟的硫酸溶液中,通过阳极氧化在Pb-0.2% Ag合金和Al棒Pb-0.2% Ag合金阳极表面形成具有高催化性能的膜层,采用显微图像分析仪和数显显微硬度计表征了膜层的厚度及硬度,并通过电子拉伸试验对比了两种阳极的极限抗拉强度.采用X射线衍射、扫描电子显微镜、循环伏安法、阳极极化和交流阻抗法等技术手段研究了Al棒Pb-0.2% Ag与Pb-0.2% Ag阳极表面氧化膜层的物相、形貌以及电化学性能.结果表明:Al棒Pb-0.2% Ag阳极相比Pb-0.2% Ag阳极表面易生成致密较厚的氧化膜层,且膜层硬度提升了41.64%,其氧化膜层主要物相均为电催化活性良好的β-PbO₂.新型阳极的极限抗拉强度是传统阳极的1.3倍,大大改善了阳极材料的机械性能.阳极极化曲线数据显示Al棒Pb-0.2% Ag/PbO₂阳极在电积锌体系中具有较低的析氧电位(1.35 V vs MSE,500 A·m-2)和较高的交换电流密度(7.079×10-5 A·m-2).循环伏安曲线和交流阻抗数据显示Al棒Pb-0.2% Ag/PbO₂阳极具有较高的电催化活性、较大的表面粗糙度和较小的电荷传质电阻.在电积锌实验中,栅栏型Al棒Pb-0.2% Ag/PbO₂阳极相比传统Pb-0.2% Ag阳极平均槽电压下降了75 mV,而且大大减少了阳极泥的产生.      

锌灰含碳球团直接还原试验

锌灰是热镀锌厂和电解锌厂生产过程中产生的一种副产品,主要成分为氧化锌,是生产直接法氧化锌的主要原料。传统的直接法氧化锌生产工艺落后,装备水平差,能源消耗高,资源回收率低。为了提高锌灰生产直接法氧化锌的绿色化水平,开发了锌灰含碳球团直接还原新技术。试验研究了不同工艺参数对锌灰含碳球团直接还原的影响关系,得到最佳的工艺条件为:还原温度为1200℃,还原时间为60min,煤粉配加量为20%,CaO配加量为4%。在上述工艺条件下,锌灰中氧化锌的还原率可以达到95.5%,显著提高了锌的回收率。     

低度复杂氧化锌矿直接法生产等级氧化锌工业试验

以低度复杂氧化锌矿为原料直接生产等级氧化锌。确定了物料的配比,解决了高铁高硅低锌氧化矿(含锌低于30%)直接生产等级氧化锌的一系列技术难题,并形成规模化生产。     

高炉上部锌在焦炭上的富集及赋存形式的研究

摘要：锌作为有害元素,在高炉内循环富集给生产带来了一系列不利影响,但锌在高炉中的赋存形式未有定论,为此,设计了一种新的实验方法,模拟研究了高炉上部锌在焦炭上的富集及赋存形式。实验结果表明,温度在493～905℃范围内,焦炭表面和内部均附集着较多的细小的颗粒状氧化锌;温度在493℃以下,焦炭表面附集着珠状金属锌和氧化锌,但内部锌较少;焦炭表面在温度低于493℃时富集的锌在493～905℃温度范围内进行转变,焦炭表面附集着白色致密结壳和众多小颗粒组成的球形氧化锌,但焦炭上仍有金属锌存在,同时焦炭内部存在的锌也较多。     

A Microscopic study of the transformation of sphalerite particles during the roasting of zinc concentrate

The formation of zinc ferrite (ZnFe₂O₄) during the roasting of iron-bearing zinc concentrates requires substantial additional processing to recover the zinc from this compound by leaching and to eliminate the iron from the leachate. The phase changes that occur in the particles of a typical industrial zinc sulfide concentrate during roasting in a fluidized bed at 1223 K were investigated by the use of light microscopy, electron microprobe analysis, and SEM with EDS. The processes which the iron undergoes during its eventual transformation into ferrite have been clarified by examination of the phases and the morphology of partially roasted marmatitic sphalerite particles (Zn, Fe)S, and by reference to the known phase equilibria involved in the Zn-Fe-S-0 system. The oxidation of ironbearing sphalerite occurs in three stages. The first involves the selective diffusion of most of the iron to the particle surface resulting in the formation of an iron oxide shell enclosing a largely unreacted zinc sulfide kernel. In the second stage, this kernel is oxidized to form a solid solution of zinc oxide and iron oxide. The iron is initially present in the ferrous state but, with the disappearance of the sulfide kernel, is oxidized to ferric iron. In the final stage, this dissolved iron oxide and the iron oxide shell react with the surrounding zinc oxide to form the refractory spinel zinc ferrite.