硼酸熔融盐除铅剂在紫杂铜中的应用研究

采用硼酸熔融盐除铅剂对紫杂铜进行了除铅实验研究,采用荧光分析仪、能谱仪(EDS)、扫描电子显微镜(SEM)及金相显微镜,分析了除铅剂成分及保温时间对除铅效果和组织性能的影响,并对其影响规律及作用机理进行了探讨.结果表明,在紫杂铜中添加适量的硼酸熔融盐除铅剂,能有效去除杂质元素铅的含量,且当配比R(H2BO3与Na2CO3质量比)为4时除铅率最高达70％以上,其他杂质含量亦均明显降低;同时能明显改善金属组织.     

稀土熔融盐精炼剂在紫杂铜中的应用研究

研究探讨了稀土元素以熔融盐的形式用于紫杂铜的精炼.通过对各种熔融盐作为精炼剂进行分析比较,确定以碳酸稀土、碳酸钠、氟化钙、金属氧化物和硼砂为稀土熔融盐的主要组成,并经过正交试验,得出了稀土熔融盐精炼剂的最佳成分配比.研究表明精炼后的紫杂铜导电率达到5.78×107 S/m,并且使氧含量保持在一级水平.     

紫杂铜精炼剂的研究现状及进展

介绍了紫杂铜中存在的杂质种类及其危害,分析了国内外关于紫杂铜精炼剂的研究现状,主要介绍了紫杂铜精炼剂的组分、作用及相关机理,阐述了精炼剂对紫杂铜显微组织、导电性能、力学性能和耐腐蚀性能等方面的影响。此外,还对稀土紫杂铜精炼剂目前仍存在的问题进行了分析和探讨,并对其研究方向提出了展望。     

浅谈杂铜火法精炼除铅

本文在介绍了杂铜含铅概况,以及目前国内除铅工艺现状.在分析除铅理论的基础上得出了影响除铅效果的三个主要因素:铜液中铅的活度系数、氧化铅的活度、反应平衡常数.简单介绍了目前国内外的几种除铅技术:硅酸盐法、磷酸法、硼酸法及FRHC法.     

浅谈杂铜火法精炼除铅

本文在介绍了杂铜含铅概况，以及目前国内除铅工艺现状。在分析除铅理论的基础上得出了影响除铅效果的三个主要因素铜液中铅的活度系数、氧化铅的活度、反应平衡常数。简单介绍了目前国内外的几种除铅技术：硅酸盐法、磷酸法、硼酸法及FRHC法。     

紫杂铜再生利用复合精炼剂的研制与应用

研制一种新型稀土盐复合精炼剂,分析并讨论这种新型稀土盐复合精炼剂对紫杂铜精炼脱氧、紫铜导电性能、力学性能的影响,阐述该稀土盐的复合精炼机理.实践表明:该精炼剂对紫杂铜的精炼有良好的效果.     

稀土对精炼紫杂铜组织和性能的影响

采用自行研制的稀土精炼剂对紫杂铜进行了精炼实验,分析和研究了添加稀土对紫杂铜精炼效果及其对组织的影响,并探讨了稀土的作用机理。实验结果表明,在紫杂铜中加入适量的稀土精炼剂,精炼和脱氧效果良好;同时,添加适量稀土元素,还可使紫杂铜晶粒细化,组织更加均匀,从而提高了紫杂铜的导电性能和力学性能。     

再生铜熔炼除铅技术研究

传统的废杂紫铜熔炼技术能耗高、加工成本高、环境污染大,严重制约再生铜工业的发展。提出利用工频感应炉进行废杂紫铜除铅技术。进行了热力学和动力学计算,结果表明:含铅量0.2%的再生铜杂质铅氧化限度为0.027%。并且通过再生铜除铅实验,降低了再生铜的含铅量和含氧量,提高了导电性。     

中频炉在紫杂铜验收中的应用

本文介绍高频炉在紫杂铜验收方面的应用。在贵溪冶炼厂，柴杂铜可分为四类：柒包线；水洗铜、杂铜；铜锭，除铜锭外，按照规定，其它类别的柴杂铜的验收都要用中频炉进行熔融浇铸，对中频炉操作的程序和工作经验作了一点小结。     

稀土钇对紫杂铜熔体的净化作用及其对铜带材组织性能的影响

在紫杂铜的熔炼过程中添加少量的稀土（0．02％、0．04％、0．06％），研究了稀土对熔体的净化作用及对铸态组织的晶粒细化作用，并对该紫杂铜的热加工及冷加工性能以及带材的组织性能进行了研究。结果表明：稀土具有净化熔体，细化铸态合金晶粒的效果，能改善紫杂铜带材的力学性能；少量稀土还可提高紫杂铜的电导率的效果。添加0．04％稀土的紫杂铜，冷轧后经过退火的带材具有良好的性能．其抗拉强度为213．8MPa；电导率为98．5％IACS，伸长率为23％。     

粗铜和粗铅中金银分析取制样方法及标准化

团结取样代表性和试样加工均匀性等问题，研究了粗铅和粗铅中金银分析试样加工粒度对金银品位的影响，产品锭内金银分布及规律，产品锭与小锭金银分布一致性及产品锭小样锭表层金银分布规律。通过在９个企业取制上千个试样，分析处理万余个数据和认真研究，为制定粗铜粗铅中银分析取制样方法提供了科学依据，并纳入粗铜粗铅技术标准。     

添加钛对炭/炭复合材料渗铜的影响

通过铺展实验和渗透实验考查添加钛对铜与C/C复合材料润湿性能的影响。采用真空熔渗的方法成功地将铜合金液渗入到C/C复合材料坯体中。对渗铜后形成的C/C-Cu复合材料进行X射线衍射、金相和扫描电镜分析。结果表明,加入12%~16%(质量分数)的钛元素粉末使铜在C/C复合材料表面有好的铺展性能;含钛铜合金渗入到C/C复合材料中有TiC形成。添加钛元素能改善C/C复合材料渗铜性能的主要原因是改善铜在C/C复合材料中的化学吸附和物理吸附特性;通过毛细管力作用,合金液渗入到C/C复合材料坯体中。     

TMA对熔融盐中铝镀层结构及耐蚀性的影响

在摩尔比为0.66:0.17:0.17的AlCl3-NaCl-KCl共融盐中添加表面活化剂四甲基氯化铵(TMA),接通直流电在铁片上获得了Al镀层.用扫描电子显微分析、X射线衍射分析和极化曲线等技术测试镀层的表面形貌、相结构及耐腐蚀性能,并用循环伏安法研究添加TMA对Al电沉积机理的影响.研究表明,添加1.0 mass%TMA时,电镀电流效率高达93.6%;纯氯化物熔盐中所得Al晶粒呈针状,为(200)面高择优取向的面心立方结构,添加TMA后获得的Al晶粒细化且形状不规则,呈无序晶面取向.添加TMA后,Al镀层的点腐蚀电位提高了0.12 V,同时增加了电沉积反应的不可逆程度,利于Al在熔融盐中的电镀.     

不同制备工艺对金属钛粉微观性质及应用的影响研究

金属钛粉末在增材制造等新型成形方法中得到越来越广泛的应用,目前主要通过熔盐电解法和气体雾化法来制取。借助X射线衍射技术(XRD)、扫描电镜(SEM)、比表面积测试(BET)、热重-差热分析法(TGA-DSC)等检测方法,从物相结构、晶胞参数、微观形貌、表面状态、热稳定性等方面,对采用熔盐电解和气体雾化2种不同工艺制取的金属钛粉的性质和应用进行全面对比分析。结果表明,电解钛粉微观形貌不规则,同一性差,适合作为粉末冶金原料和热还原剂;气雾化钛粉微观形貌为均匀球状,表面不易吸附气体杂质,比表面积为3.69 m~2/g,更适宜作为增材制造的原材料。     

过冷DD3单晶高温合金的净化影响因素及途径

以特制的复合熔盐作为净化剂在氩气氛保护及循环过热条件下去除DD3单晶高温合金熔体中的异质晶核 ,获得了最大 2 1 0K过冷度。详细探讨了复合熔盐净化机制 ,同时对比分析了纯循环过热和熔融玻璃净化方式对于DD3单晶高温合金获得深过冷的可行性     

Corrosion of type 316L stainless steel in molten LiCl–KCl salt

Pyrochemical reprocessing in molten chloride salt medium has been considered as one of the best options for the reprocessing of spent metallic fuels. The AISI 316L stainless steel (SS) is envisaged as a candidate material for the fabrication of components for various unit operations like salt preparation vessel, electro‐refiner and cathode processor, on which ceramic coatings with metallic bond coat will be applied by the thermal plasma spraying. The unit operation like electro‐refining is carried out in the molten lithium chloride–potassium chloride (LiCl–KCl) eutectic salt at 773 K in argon atmosphere. The corrosion behaviour of the container vessel in molten chloride salts is therefore important, hence corrosion tests were carried out in a molten salt test assembly under argon gas atmosphere. The present paper discusses the corrosion behaviour of 316L SS in the molten LiCl–KCl eutectic salt at 873 K. The 316L SS samples were immersed in the molten LiCl–KCl eutectic for 25, 100 and 250 h, while 316L SS with yttria stabilized zirconia coating was exposed for 1000 h. The exposed samples were examined by optical and scanning electron microscope for corrosion attack. The X‐ray mappings of the cross‐section of the degraded layer onto the 316L SS indicated that the mechanism of corrosion corresponds to the selective diffusion of Cr to the surface with the formation of voids below, and the formation of chromium compounds at the surface. The results of the present study indicated that the yttria stabilized zirconia coating onto the 316L SS exhibits a better corrosion resistance in molten chloride salt than with uncoated 316L SS.     

Industrial development of a novel sulfate system for copper pyro-refining

The results of a complete series of industrial-scale tests carried out at the Noranda Horne smelter using a novel molten sulfate salt for copper pyro-refining are described in this article. In the process, copper co-exists with a molten oxide layer and a molten CaSO₄-Na₂SO₄ layer, both of which have refining capabilities. The effect of the composition of the sulfate salt and that of the copper oxide slag on the distribution of minor elements between copper, oxidic slag, and the sulfate phase are presented. Pascal Coursol is a Ph.D. candidate at the Center for Computational Thermochemistry (école Polytechnique de Montréal) and is currently a process scientist with Alcan International. Nathan Stubina is a Six Sigma master black belt and Eva Carissimi is smelter manager with Noranda Inc.-Horne Division. Manuel Zamalloa and Phillip Mackey are principal scientists with Falconbridge, respectively, at Falcondo Division and the Falconbridge Technology Center.     

化学处理液中的La及BTA 对铜合金表面性能的影响

为了提高铜及其合金的耐蚀性能,研究了稀土La盐与BTA对铜合金缓蚀的协同作用,化学处理后的铜合金表面耐蚀性能得到改善。利用扫描电镜及XRD,对铜合金处理后的表面形貌及结构进行了分析;通过阳极极化、交流阻抗等电化学测试方法分析了La盐与BTA对铜合金表面性能的影响。结果表明:稀土La盐与BTA的加入使铜合金表面形成了均匀、致密的转化膜,从而提高了铜合金表面的耐蚀性能。     

Interpretation of evaporation behavior of lead from molten copper by the mass-transfer model in fluid flow

Recently, an increasing tendency to eliminate the lead in alloy design has been found because of its harmfulness in health. The lead is required to be removed from copper scrap for recycling. In order to get fundamental knowledge on the use of cheap copper scrap in the manufacturing of lead-free copper alloy, the possibility of removal of lead by gas bubbling from the molten copper alloy has been investigated. The influence of Ar gas flow rate was investigated based on the reaction kinetics and mass transport model. The removal rate of lead was increased with an increase of flow rate of Ar and temperature. The overall removal rate of lead from the molten copper alloy has been calculated from experimental results, and the mass transport of lead in the gas phase (the absolute molar flux of lead) was calculated from the one-dimensional steady state diffusion model. The calculated mass flux of lead in the model is found to be quite similar to the overall removal rate of lead obtained from experimental results. The mass transport of lead vapor in the gas phase seems to be a major part of the rate-controlling steps, under the present experimental condition.     

Copper corrosion in drinking water systems – effect of pH and phosphate‐dosage

Copper corrosion in residential plumbing installations can lead to an increase in copper concentration in drinking water as well as to leakages. Central water treatment steps such as pH‐adjustment or dosages of phosphate‐based inhibitors are measures in reducing copper corrosion. Especially phosphate in drinking water is believed to work as a corrosion inhibitor, but it is currently uncertain as to how this inhibitor works. In some cases the phosphate dosage aggravated the copper corrosion. The mechanisms are not yet clear and the influence of phosphate and pH remain a question to be answered. The results of a German Gas and Water Works Association (DVGW) research project on copper corrosion are presented as follows. The influence and the mechanisms of decarbonisation, deacidification and phosphate dosing on copper release in residential plumbing installations were studied in pipe rig experiments according to the German standard DIN 50931‐1. It shows that an increased pH‐value can lead to a decrease in copper content and that a phosphate dosage can lead to both higher and lower copper concentrations.