Kinetic mechanism of copper extraction from methylchlorosilane slurry residue using hydrogen peroxide as oxidant

Copper was extracted from methylchlorosilane slurry residue by a direct hydrogen peroxide leaching method.A number of experimental parameters were analyzed to determine the extraction efficiency of copper.The extraction efficiency of copper reached 98.5%under the optimal leaching conditions,such as the hydrogen peroxide concentration of 1.875 mol·L^(-1),the leaching temperature of 323 K,the liquid–solid ratio of 20 ml·g^(-1),and the stirring speed of 300 r·min^(-1).The leaching kinetics of the copper extraction process was then described by the shrinking core model.There were two stages.The first stage was controlled by chemical reactions,while the second stage was controlled by interface transfer and product layer diffusion.The activation energy and kinetic control equations were determined,as well as an explanation of the leaching mechanism of copper extraction based on kinetic analysis and materials characterization.Copper resources can be recovered from the methylchlorosilane slurry residue efficiently and inexpensively with the methods used in this study.

Leaching kinetics of low-grade copper ore containing calcium-magnesium carbonate in ammonia-ammonium sulfate solution with persulfate

The leaching kinetics of copper from low-grade copper ore was investigated in ammonia-ammonium sulfate solution with sodium persulfate. The effect parameters of stirring speed, temperature, particle size, concentrations of ammonia, ammonium sulfate and sodium persulfate were determined. The results show that the leaching rate is nearly independent of agitation above 300 r/min and increases with the increase of temperature, concentrations of ammonia, ammonium sulfate and sodium persulfate. The EDS analysis and phase quantitative analysis of the residues indicate that bornite can be dissolved by persulfate oxidization. The leaching kinetics with activation energy of 22.91 kJ/mol was analyzed by using a new shrinking core model （SCM） in which both the interfacial transfer and diffusion across the product layer affect the leaching rate. A semi-empirical rate equation was obtained to describe the leaching process and the empirical reaction orders with respect to the concentrations of ammonia, ammonium sulfate and sodium persulfate are 0.5, 1.2 and 0.5, respectively.

Leaching kinetics of low-grade copper ore with high-alkality gangues in ammonia-ammonium sulphate solution

The leaching kinetics of low-grade copper ore with high-alkality gangues was studied in ammonia-ammonium sulphate solution.The main parameters,such as ammonia and ammonium sulphate concentrations,particle size,solid-to-liquid ratio and reaction temperature,were chosen in the experiments.The results show that the increase of temperature,concentrations of ammonia and ammonium sulphate is propitious to the leaching rate of copper ore.The leaching rate increases with the decrease of particle size and solid-to-liquid ratio.The leaching rate is controlled by the diffusion through the ash layer and the activation energy is determined to be 25.54 kJ/mol.A semi-empirical equation was proposed to describe the leaching kinetics.

Acid equilibrium during bioleaching of alkaline low-grade sulfide copper ore

This article reports the study on acid equilibrium during bioleaching of alkaline low-grade copper sulfide ore. Adding auxiliary agents 1# （sulfur） and 2# （pyrite） makes bacterial leaching of copper and acid production carried out simultaneously because the auxiliary agents can be oxidized by bacteria and the oxidation products involve acid. The acid required for dissolving alkaline gangue during bacterial leaching is produced, and acid equilibrium is reached during the ore bio-leaching. The recovery of copper reaches more than 95%.

Dissolution of Nickel in Copper Residue Generated from Nickel Matte Refining

The dissolution behavior of nickel during the oxygen chloride leaching of the copper residue was investigated.Technological variables of the leaching,including oxygen flow rate,concentrations of chloride and sulfuric acid,and temperature,were discussed.

Chemical Forms and Phytoavailability of Copper in Soil as Affected by Crop Residues Incorporation

Preceding crops as a source of organic matter are important sources of micronutrient and can play an important role in the soil fertility and soil cycling of micronutrients. In addition to the role of the organic matter in increasing the concentration of micronutrients in soil solution, attention should be also paid to the role of the kind and the quantity of the root’s exudates released in response to the incorporation of different plant residues in the rhizosphere. Present research was conducted with the objective of studying the effect of the kind of preceding crops: Trifolium (Trifolium pretense L) and Sorghum (Sorghum bicolor L) on chemical forms of copper (Cu) in solid phases of a calcareous soil in a completely randomized block field experiment with split plot (3 m × 5 m) arrangement, consisting of 3 replications and 3 treatments. After incorporation of the residue, wheat (genotype back cross) was planted. After harvesting the wheat, soil samples were collected from root zone of wheat. Selected soil properties and chemical forms of Cu were determined in the solid phases of the soil samples. Incorporation of plant residues significantly increased the concentration of DTPA-extractable Cu, in the soil. The highest effect was obtained for Trifolium treatment. Incorporation of plant residues decreased the carbonate-bound Cu (Cu-Carb) fraction in the solid phase and increased oxide-bound Cu (Cu-Ox) as compared to the control (fallow treatment). Fraction of organic-bound Cu (Cu-Org) in the soil increased with incorporation of plant residues as compared with the fallow treatment. Trifolium was the most effective in increasing Cu-Org. Cu-Ox and Cu-Residual (Cu-Res) forms showed a significant negative correlation and Cu-Org showed a significant positive correlation with the concentration of DTPA-extractable Cu. Incorporation of Trifolium residues decreased the fraction (%) of Cu-Carb and Cu-Ox (less soluble forms) and consequently increased the fraction (%) of Cu-Org which in turn elevated the concentration of DTPA-extractable Cu. Trifolium was the most effective in increasing the phytoavailability of Cu in soil.

Bio-leaching of low-grade large porphyry chalcopyrite-containing ore

In order to economically recover the copper from the low grade copper ores, a bioleaching solvent extraction electrowinning plant with a design capacity of 2 000 t cathode copper per year in Dexing Copper Mine was operated in September, 1997. The results during the 10 month period of the industrial copper dump leaching have been obtained and the approaches have been carried out to enhance the copper dissolution from the waste rocks. The overall operation flowsheet is depicted. The problems confronted in the process and possible way for improving are discussed.

Cooperative removal of Mn^(2+),NH_(4)^(+)-N,PO_(4)^(3-)-P and F−from electrolytic manganese residue leachate and phosphogypsum leachate

Electrolytic manganese residue leachate(EMRL)contains plenty of Mn^(2+) and NH_(4)^(+)-N,and phosphogypsum leachate(PGL)contains large amounts of PO_(4)^(3-)-P and F^(-).Traditional methods of EMRL and PGL discharge could seriously damage the ecological environment.In this study,an innovative method for cooperative removal Mn^(2+),NH_(4)^(+)-N,PO_(4)^(3-)-P,F^(-)from PG and POFT was studied.The result showed that Mn^(2+),PO_(4)^(3-)-P and F^(-)were mainly removed in forms of Mg_(3)Si_(4)O_(10)(OH)_(2),Mn_(3)O_(4),Mn_(3)(PO_(4))_(2),Mg_(3)(PO_(4))_(2),CaSO_(4)·2H_(2)O,MnF_(2),MnOOH and Ca_(2)P_(2)O_(7)·2H_(2)O,when LG-MgO was used to adjust the pH value of the system to 9.5,and the volume ratio of EMRL and PGL was 1:4,as well as reaction for 1 h at 25℃.NH_(4)^(+)-N was mainly removed by struvite precipitate,when the molar ratio of N:Mg:P was 1:3:2.4.The concentrations of Mn^(2+),NH_(4)^(+)-N and F^(-)were lower than the integrated wastewater discharge standard.The concentration of PO_(4)^(3-)-P decreased from 254.20 mg/L to 3.21 mg/L.This study provided a new method for EMRL and PGL cooperative harmless treatment.

Elimination of Oil Residual inside the Copper Pipe Using Ladder Technique

This study presents the methodology to eliminate oil residual in copper pipe due to rolling process for manufacturing coil used in air conditioner. The pressure caused by Nitrogen flow rate was applied starting from 0, 5, 10, and 15 bar, respectively which was depending on time delay and pipe length. The developed system was divided into 2 modules: Parallel pressure ladder module (PPLM) [1] and Serial pressure ladder module (SPLM) which were experimented with 2 sizes of copper pipe: diameter 7.29 mm, thickness 0.25 mm, and length 10 km, and diameter 8 mm, thickness 0.25 mm, and length 10 km. From experiment, it can be noted that PPLM would perform better in elimination of oil residual compared to SPLM. About 97.44% (0.04 mg/m) and 97.59% (0.05 mg/m) of oil residual can be respectively eliminated from diameter 7.29 mm pipe and diameter 8 mm pipe which exceeded the standard allowance of 30% or 0.1 mg/m. Moreover, the cost of Nitrogen can be reduced by 6.25% per month.

铜冶炼铼浸出渣中铋的浸出试验研究

采用盐酸对铼浸出渣浸出,考察了盐酸浓度、反应温度、搅拌强度、反应时间等因素对Bi浸出率的影响,得到了最有利条件下Bi浸出率,在最有利条件下,Bi的浸出率可以达到95%以上,最大限度实现了Bi的回收,效益明显。

电感耦合等离子体原子发射光谱(ICP-AES)法测定真空精炼镁合金物料中铁、铜、镍

真空精炼是目前镁金属提纯的重要工艺,工艺原料及真空精炼提纯镁金属过程残留物中Fe、Cu、Ni含量的准确测定对工艺参数的优化及调整具有重要的指导作用。传统测定方法中以邻二氮杂菲分光光度法、新亚铜灵分光光度法、丁二酮肟分光光度法测定三种元素含量,结果准确,但操作繁琐,周期较长,难以满足工业生产中高效、快速测定的需要,且方法中所需的有机萃取剂对环境污染较大。选择电感耦合等离子体发射光谱(ICP-AES)法测定真空蒸馏精炼镁合金物料中Fe、Cu、Ni,系统探究溶解酸、溶解温度、溶解时间对物料溶解和测定的影响,选择盐酸(1+1)和过氧化氢溶解体系,200℃加热条件下反应20 min为最佳消解镁合金原料条件;选择王水溶解体系,200℃加热条件下反应25 min为真空精炼残留物最佳溶解条件。并探讨ICP-AES测定过程中各元素的检出限和测定下限以及共存元素的干扰情况,建立了ICP-AES法测定真空精炼提纯镁合金物料的方法。测定结果的相对标准偏差(RSD,n=11)为Fe 5.9%~11.5%、Cu 2.6%~11.8%、Ni 3.4%~11.5%,各元素加标回收率为Fe 96.4%~102%、Cu 101%~108%、Ni 103%~105%;按照建立的方法测定镁合金原料、真空精炼残留物中的铁、铜、镍,并与国家标准方法测定结果进行对比,结果相一致。实现了ICP-AES法快速、准确测定真空蒸馏精炼镁合金物料中铁、铜、镍含量,对及时、高效、准确评估真空精炼提纯镁工艺及产品具有重要意义。

基于分段T值曲线拟合的双能X射线的铜矿分选研究

针对传统T值曲线拟合算法的双能X射线透射技术分选铜矿偏差较大的问题,提出了一种分段T值曲线拟合方法,该方法将厚度进行区间划分,在每个区间内进行一次T值曲线拟合来对铜矿进行分选,能更准确体现不同厚度下T值的变化趋势,减小厚度给分选带来的影响。采用高能、低能射线拟合T值曲线,再在各个区间内计算T值与曲线拟合映射值的残差,不同物质残差也存在不同,以此达到分选铜矿的目的。验证实验结果表明,对两类不同品位的铜矿进行分选,将经过分段T值曲线拟合的矿石图像放入ResNet18神经网络中进行训练,并用训练好的模型进行测试,测试准确率达到88.67%。

高冰镍浸出渣还原浸出工艺研究

以湿法冶炼高冰镍过程中产生的高冰镍浸出渣为研究对象,采用二氧化硫对高冰镍渣加压还原浸出,考察了初始硫酸浓度、液固比、通气方式、浸出温度和浸出时间对高冰镍渣还原浸出过程铜、铁行为的影响;对还原浸出液采用置换沉淀和冷冻结晶的方法,对还原浸出中铜和铁进行分离回收。结果表明:在初始硫酸浓度100 g/L、液固比6 mL/g、反应时间3 h、反应温度90℃、二氧化硫分压0.15 MPa的条件下,铁和铜的浸出率分别为99.35%、77.46%,浸出液中铁几乎全部为亚铁离子;在硫酸含量20~30 g/L、温度70℃、铁粉加入量5.7 g/L、反应时间40 min的条件下,对还原浸出液进行置换沉铜,沉铜率达到了99.70%,渣含铜为67.91%。在温度—10℃、保温时间20~30 min、初始硫酸浓度100 g/L的条件下,对沉铜后液进行冷冻结晶制备硫酸亚铁,铁沉淀率达到了72.6%,七水硫酸亚铁纯度达到了92.93%。

胶原蛋白及自退火行为对电解铜箔翘曲性能的影响

电解铜箔在生产过程中极易出现铜箔翘曲度高等问题,严重影响铜箔后续加工和装配,是电解铜箔的关键共性难题之一。本文以不同浓度的胶原蛋白作为添加剂,研究了胶原蛋白对电解铜箔翘曲度的影响,并探讨了其作用机制。结果表明,胶原蛋白的最佳加入量为10 mg/L,此时铜箔的抗拉强度达到382.5 MPa,翘曲度大幅降低至16 mm。随着胶原蛋白浓度的升高,铜箔的抗拉强度不断增加。胶原蛋白通过促进铜箔形成(220)Cu晶面择优取向,降低铜箔表面粗糙度,显著改善铜箔的翘曲度。加入10 mg/L胶原蛋白,铜箔的(220)Cu晶面的织构系数(Tc)增加到57.8%,毛面粗糙度Rz降低到1.9μm,翘曲度降至16 mm。由于胶原蛋白残留在铜箔内部,导致铜箔发生自退火行为。铜箔通过自退火释放了部分残余应力,使得铜箔的翘曲度进一步降低至9 mm。因此,胶原蛋白是一种有效降低铜箔翘曲度的添加剂,并且能够通过之后的自退火行为,进一步降低铜箔的翘曲度。

基于改进残差网络与迁移学习的铜合金金相图分类方法

针对铜合金领域特定金相的数据集通常非常小,无法满足传统卷积神经网络建模需要大量训练样本的问题,提出一种基于改进残差网络与迁移学习的铜合金金相图分类方法,即基于ImageNet数据集和金相图训练集预先训练ResNet50残差模型,训练时采用迁移学习(Transfer Learning)方法并重新建立全连接层对铜合金金相类别进行分类识别。本方法的准确率为97.2%,精确率为95.6%,召回率为97.3%,F1分数为96.4%,优于VGG19和基于迁移学习的MobileV2等方法。实验结果表明,采用迁移学习方法可以克服金相图像数据集小的问题,使用ResNet50进行特征提取可以很好地获得铜合金金相图的纹理信息。本研究建立了一种铜合金金相结构自动分类和识别的新方法,可较准确地分类和识别铜合金金相图。

刚果(金)某铜精矿酸浸渣中铜的赋存特征及回收

刚果(金)地区主要采用湿法炼铜工艺提取铜精矿中的铜,含铜55%~65%的硫化铜精矿经过焙烧和两段酸浸后,酸浸渣中含有3%~10%的铜。以刚果(金)某铜精矿焙砂酸浸渣为研究对象,在对其进行工艺矿物学分析的基础上,采用加压浸出方式回收渣中的铜。结果表明,铜精矿焙砂酸浸渣中的铜主要以硅孔雀石、胆矾和亚铁酸铜的形式存在,三种矿物所含铜占总铜量的96.87%,其中亚铁酸铜为主要难浸矿物;酸浸时,酸用量对铜浸出率影响最大;最佳浸出条件为液固比4 mL/g、酸矿比(硫酸用量与酸浸渣的质量比)65%、浸出时间2 h、浸出温度180℃,对应的铜浸出率为94.52%,渣含铜可由处理前的7.66%降低到0.52%。

混配铜精矿对我国砷污染防治的影响与对策

砷是我国重点防控的重金属之一,铜冶炼是主要的砷污染物排放源。基于实地调研、专家咨询及行业数据统计等方法,分析了我国混配铜精矿进口量的变化情况和铜冶炼过程中砷的流向,探讨了混配铜精矿进口量的增加对我国砷污染防治的影响,并提出了相应的砷污染防治对策和建议,指出:应对配置混矿的企业进行全流程监管;加强对铜冶炼企业和含砷废物处理处置企业的环境监管;开展含砷废物的资源化利用研究,逐步提高含砷废物的资源化利用率;拓展含砷废物无害化处理路径,降低环境风险。

冷轧和退火对压延铜箔残余应力和力学性能的影响

对150μm厚铜箔母材进行4道次可逆冷轧,轧制至35μm厚,再在180℃下进行1 h退火处理,研究了冷轧和退火对压延铜箔显微组织、表面残余应力以及力学性能的影响。结果表明:经过冷轧处理后,铜箔的晶粒明显细化,平均晶粒尺寸减小至5.7μm,织构由退火织构转变为形变织构;经退火处理后,平均晶粒尺寸增大至9.4μm,织构恢复为退火织构。冷轧后铜箔的表面残余应力急剧增加至543.02 MPa,硬度增加,平均耐弯折疲劳寿命延长,平行于轧制方向(RD)的抗拉强度提高,而断后伸长率和TD面(TD为轧板横向)的表面粗糙度下降。经退火处理后,铜箔的表面残余应力恢复至237.47 MPa,硬度降低,TD面的表面粗糙度稍微增加,抗拉强度降低和断后伸长率有所提高,平均耐弯折疲劳寿命进一步延长。

湿法炼锌净化渣二次利用技术研究及应用

针对湿法炼锌三段净化工艺存在锌粉用量大、成本高等问题,采用净化二、三段渣代替锌粉用于净化除杂,用于提高净化渣中金属锌利用率并优化镉回收钴渣走向,结果表明:净化渣用于镉回收时,Ge、Co、Cu、Cd脱除率分别达到83.82%、94.09%、95.55%、96.77%;钴渣零产量、系统锌湿法直收率提升0.5%~1.4%;海绵镉锌粉单耗由3.54 t/t·Cd降至0.88 t/t·Cd。

氰渣有价金属浮选回收试验研究与应用

为提高氰渣的资源利用率,解决氰渣中有价金属浮选精矿品位不高、回收率低的问题,开展了氰渣性质分析及回收铜、铅、锌的试验研究。根据试验研究结果,结合现场实际情况进行了工艺优化改造和药剂制度调整,生产实践表明:采用铅优先浮选—浮铅尾矿选铜工艺流程,在铅浮选活化剂ZJT用量3000 g/t、捕收剂乙硫氮用量100 g/t,铜浮选活化剂ZJT用量2500 g/t、捕收剂ZJB-2用量100 g/t,浮选流程均为一次粗选两次精选两次扫选的条件下,可以获得铅精矿铅品位22.32%、铅回收率45.76%,锌品位14.47%、锌回收率31.78%,铜精矿铜品位15.38%、铜回收率42.22%的良好指标。改造后,铅精矿铅、锌品位合计提高8~40百分点,铜精矿铜品位提高3~13百分点。