Sequential removal of selenium and tellurium from copper anode slime with high nickel content

A process using soda roasting-alkaline leaching-acid leaching to remove selenium, tellurium and copper sequentially from the copper anode slime with high content of Ni was tested. The mechanism of this process was outlined based on thermodynamic analysis and the change in the XRD patterns of different intermediate products. During soda roasting, copper which occurs as Cu4SeTe in the slime was oxidized to CuO and Cu3TeO6, while selenium and tellurium were oxidized to Ag2SeO4 and Cu3TeO6, respectively. Ag2SeO4 in the calcine is easily leached in the subsequent alkaline leaching, but CuTeO3 resulted from the decomposition of CCu3TeO6 remains inactive in this process through which selenium is leached out in preference to tellurium. The CuTeO3 and Cu O in the alkaline leaching residue can be leached in the following sulfuric acid leaching process. More than 97% of selenium was leached with little tellurium leached under the optimal condition. Then, more than 96% of copper and almost all the tellurium were leached out in the following acid leaching process.

Optimization on selenium and arsenic conversion from copper anode slime by low-temperature alkali fusion process

A process was proposed to convert and separate selenium and arsenic in copper anode slime(CAS) by low-temperature alkali fusion process.Central composite design was employed to optimize the effective parameters,in which Na OH/CAS mass ratio,fusion temperature and fusion time were selected as variables,and the conversion ratio of selenium and arsenic as responses.Second-order polynomial models of high significance and 3D response surface plots were constructed to show the relationship between the responses and the variables.Optimum area of >90% selenium conversion ratio and >90% arsenic conversion ratio was obtained by the overlaid contours at Na OH/CAS mass ratio of 0.65-0.75,fusion temperature of 803-823 K and fusion time of 20-30 min.The models are validated by experiments in the optimum area,and the results demonstrate that these models are reliable and accurate in predicting the fusion process.

Alkaline pressure oxidative leaching of bismuth-rich and arsenic-rich lead anode slime

A new alkaline pressure oxidative leaching process(with NaNO3 as the oxidant and NaOH as the alkaline reagent)is proposed herein to remove arsenic,antimony,and lead from bismuth-rich and arsenic-rich lead anode slime for bismuth,gold,and silver enrichment.The effects of the temperature,liquid-to-solid ratio,leaching time,and reagent concentration on the leaching ratios of arsenic,antimony,and lead were investigated to identify the optimum leaching conditions.The experimental results under optimized conditions indicate that the average leaching ratios of arsenic,antimony and lead are 95.36%,79.98%,63.08%,respectively.X-ray diffraction analysis indicated that the leaching residue is composed of Bi,Bi2O3,Pb2Sb2O7,and trace amounts of NaSb(OH)6.Arsenic,antimony,and lead are thus separated from lead anode slime as Na3AsO4·10H2O and Pb2Sb2O7.Scanning electron microscopy and energy-dispersive spectrometry imaging revealed that the samples undergo appreciable changes in their surface morphology during leaching and that the majority of arsenic,lead,and antimony is removed.X-ray photoelectron spectroscopy was used to demonstrate the variation in the valence states of the arsenic,lead,and antimony.The Pb(IV)and Sb(V)content was found to increase substantially with the addition of NaNO3.

Leaching kinetics of selenium from copper anode slimes by nitric acid-sulfuric acid mixture

The leaching kinetics of selenium from copper anode slimes was studied in a nitric acid?sulfuric acid mixture.The effects of main parameters on selenium leaching showed that the leaching rate of selenium was practically independent of stirring speed,while dependent on temperature and the concentrations of HNO3and H2SO4.The leaching of selenium includes two stages.The activation energy in the first stage is103.5kJ/mol,and the chemical reaction is the rate controlling step.It was almost independent of H2SO4concentration and dependent on HNO3concentration since the empirical reaction order with respect to HNO3concentration is0.5613.In the second stage,the activation energy is30.6kJ/mol,and the process is controlled by a mixture of diffusion and chemical reaction.The leaching of selenium was almost independent of HNO3concentration.

Intensification of pretreatment and pressure leaching of copper anode slime by microwave radiation

The application of microwave irradiation for pretreatment of copper anode slime with high nickel content prior to pressure sulfuric acid leaching has been proposed.The microwave-assisted pretreatment is a rapid and efficient process.Through the technology of microwave assisted pretreatment-pressure leaching of copper anode slime,copper,tellurium,selenium and nickel are almost completely recovered.Under optimal conditions,the leaching efficiencies of copper,tellurium,selenium and nickel are 97.12%,95.97%,95.37% and 93.90%,respectively.The effect of microwave radiation on the temperature of copper anode slime and leaching solution is investigated.It is suggested that the enhancement on the recoveries of copper,tellurium and selenium can be attributed to the temperature gradient which is caused by shallow microwave penetration depth and super heating occurring at the solid–liquid interface.The kinetic study shows that the pressure leaching of copper anode slime,with and without microwave assisted pretreatment,are both controlled by chemical reactions on the surfaces of particles.It is found that the activation energy calculated for microwave-assisted pretreatment-pressure leaching(49.47 kJ/mol) is lower than that for pressure leaching which is without microwave assisted pretreatment(60.57 kJ/mol).

Preparation of pure SbCl_3 from lead anode slime bearing high antimony and low silver

A novel treatment process of lead anode slime bearing high antimony and low silver was developed by a potential-controlled chloridization leaching and continuous distillation.The experimental results show a high Sb 3+ concentration,489.2 g/L,in the leaching solution for two-stage countercurrent leaching process,and the leaching rates of Sb,Cu,Bi more than 99% when the potential is controlled at 450 mV.When the leaching solution is distillated and concentrated at 120°C,almost all the silicon compound is evaporated into the concentration distillate and exists as amorphous hydrated silica.By the continuous distillation,high pure SbCl3 could be prepared,and AsCl3 is enriched in the distillate while metals Bi,Cu are enriched in the continuous distillation residue.As a result,the recovery rate of Sb is more than 95%.

φ-pH diagram of As-N-Na-H_2O system for arsenic removal during alkaline pressure oxidation leaching of lead anode slime

In order to illustrate the thermodynamic characteristics of arsenic during alkaline pressure oxidation leaching process oflead anode slime(NaNO3as oxidant;NaOH as alkaline reagent),theφ-pH diagrams of As-Na-H2O,N-H2O,As-N-Na-H2Osystems at ionic mass concentration of0.1mol/kg and temperatures of298,373,423and473K were established according tothermodynamic calculation.The results show that the existence forms of arsenic are associated with pH value,which mainly exists inthe forms of H3AsO4,24H AsO-,24HAsO-,H2AsO2-and As2O3in lower pH region,while it mainly exists in the form of3AsO4-when pH>11.14.High alkali concentration and high temperature are advantageous to the arsenic leaching.The alkaline pressureoxidation leaching experiments display that the tendency of arsenic leaching rate confirms the thermodynamic analysis resultsobtained from theφ-pH diagrams of As-N-Na-H2O system,and the highest leaching rate of arsenic reaches95.85%at453K.

Selective extraction of gold(Ⅲ) from hydrochloric acid-chlorine gas leach solutions of copper anode slime by tri-butyl phosphate(TBP)

The oxidative leaching causes to dissolve various impurities such as Fe, Cu, Pd, Se in copper anode slime. Organicextractant tri-butyl phosphate (TBP) was used to purify leach solution. Several parameters, such as TBP, HCl and chloride inorganicsalt concentrations were chosen in order to determine efficient state for impurities separation. Standard solvent extraction tests forextraction and separation of Au, Pd, Pt, Fe, Cu and Se were conducted with equal volume of aqueous and organic phases in batchexperiments. The effect of hydrochloric acid, organic phase and metals initial concentration were examined at ambient temperature. Itwas found that 0.25 mol/L TBP in the presence of 2.5 mol/L hydrochloric acid can cause high extraction of gold. Meanwhile, in theseconditions the extraction of other impurities is negligible. After extraction, pregnant organic phase was scrubbed by distilled waterand some impurities were removed. Finally, gold was stripped by sodium thiosulfate solution. The stripping solution does not haveany impurities. By adding H2SO4 to stripping solution containing Na2S2O2, SO2 gas is released and Au3+ ions could be reduced.

Ultra fast microwave-assisted leaching for the recovery of copper and tellurium from copper anode slime

The decomposition of copper anode slime heated by microwave energy in a sulfuric acid medium was investigated. Leaching experiments were carried out in a multi-mode cavity with microwave assistance. The leaching process parameters were optimized using response surface methodology（RSM）. Under the optimized conditions, the leaching efficiencies of copper and tellurium were 99.56% ± 0.16% and 98.68% ± 0.12%, respectively. Meanwhile, a conventional leaching experiment was performed in order to evaluate the influence of microwave radiation. The mechanism of microwave-assisted leaching of copper anode slime was also investigated. In the results, the microwave technology is demonstrated to have a great potential to improve the leaching efficiency and reduce the leaching time. The enhanced recoveries of copper and tellurium are believed to result from the presence of a temperature gradient due to the shallow microwave penetration depth and the superheating at the solid-liquid interface.

Ag recovery from copper anode slime by acid leaching at atmospheric pressure to synthesize silver nanoparticles

In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted ofCu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4% （by weight）. The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ~C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea- ched as well as Ag. To separate Ag from leach solution HCI was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabilizers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.

Study on selenium extraction from anode slime

Taking a copper anode slime as the raw material, a novel process for selenium extraction was studied. The primary selenium recovery can reach above 88.5% and the quality index of selenium product can be up to 99.5%. The economic benefit resulted is remarkable and environment has been protected.

铜阳极泥中有价元素湿法回收工艺研究进展

我国铜生产量居世界第一,其中80%采用火法冶炼工艺。冶炼过程中产生的铜阳极泥富含Cu、Ag、Au、Se、Te等多种有价元素,具有很高的回收价值。本文分析对比了铜阳极泥的主流处理工艺,其中,湿法工艺作为一种低能耗高效浸出工艺,近些年被广泛地研究。文章系统综述了铜阳极泥湿法处理工艺研究进展,归纳了铜阳极泥氧化浸出、物理强化浸出等预处理方法,总结了铜阳极泥中Cu、Se、Te以及贵金属Ag、Au的回收方法及反应机理。基于当前的研究进展,未来应重点关注湿法工艺的绿色性,开发用于浸出、配合、萃取等过程的绿色试剂,并加强对阳极泥中稀贵金属(Pt、Pd、Rh等)回收的研究,同时需要提升不同元素选择性分离的能力,以获得高纯度产品。

用氯化浸出法从铜阳极泥中回收单质砷

研究了采用氯化浸出—NaH_(2)PO_(2)选择性还原工艺回收铜阳极泥中的单质As。考察了液固体积质量比、初始酸度、浸出温度、初始Cl^(-)质量浓度、浸出时间对As浸出率的影响,以及还原温度、NaH_(2)PO_(2)与As的物质的量比、还原时间对As还原沉淀率的影响。结果表明:最佳氯化浸出条件为初始酸度220g/L,液固体积质量比6/1,浸出温度70℃,初始Cl^(-)质量浓度150g/L,浸出时间2.5h;最佳还原条件为还原温度80℃,NaH_(2)PO_(2)与As的物质的量比2/1,还原时间2h;在最佳条件下所得单质As产品中As平均质量分数为90.44%,产品质量符合单质As的精制要求。

铜阳极泥湿法预处理除杂同步富集稀贵金属

铜阳极泥高效预处理除杂是分离精炼稀贵金属的前置关键环节。本文基于铜阳极泥的理化特征,提出H_(2)SO_(4)-H_(2)O_(2)体系常压选择性自催化氧化除杂同步高效富集稀贵金属新工艺,考察了多种因素对Cu、As、Se、Te浸出率的影响。结果表明:铜阳极泥主要物相为PbSO_(4)、CuSO_(4)、Ag_(2)Se、Cu_(2)Te、Cu_(2)Se和Cu等,在H_(2)SO_(4)用量120 mL/kg、H_(2)O_(2)用量260 mL/kg、液固质量比5∶1、反应温度35℃和反应时间1 h的优化条件下,Cu、As的浸出率分别为98.33%、58.22%,Se、Te的浸出率分别仅为7.49%和23.97%,而Au和Ag均未浸出。浸出渣微观组织为尺寸50~100 nm的镶嵌式团状颗粒,主要由PbSO_(4)、Se、Ag_(2)Te和Ag物相组成,原料中Cu_(2)Te、Cu_(2)Se和Ag_(2)Se物相明显消失。浸出渣中Ag和Au的含量分别为9.33%和0.293%,富集比为1.5,Cu含量由14.30%降至0.39%,满足后续贵金属分离精炼要求。该工艺在常温常压下实现了铜阳极泥中杂质的高效分离和稀贵金属的定向富集。

侧吹炉协同处理铜阳极泥浸出渣回收有价金属新工艺研究

采用侧吹炉协同处理铜阳极泥浸出渣,综合回收有价金属,考察了纯碱用量、粒煤用量、沉淀时间、炉顶烟气温度对主金属Pb、Sb、Bi、Au、Ag回收率的影响。结果表明,适宜的处理工艺参数为:纯碱用量2.5%、粒煤用量3%、沉淀时间1.5 h、炉顶烟气温度750℃,此时贵铅中Au品位达到1 544 g/t(富集了1.84倍)、Ag品位达到10.37%(富集了1.4倍)、Pb品位达到22.89%(富集了2.1倍)、Bi品位达到27.45%(富集了2.2倍)。

铜阳极泥选冶联合工艺有价金属走向考察及改进建议

铜阳极泥是资源综合回收的优选对象,分析各有价金属的分散情况对后续的回收有着指导性的方向作用。铜阳极泥选冶联合工艺较为成熟,具有不断外延拓展金属回收的空间。针对4000 t铜阳极泥物料的生产数据,考察了该工艺有价金属的走向,统计分析了金、银、硒、碲、铅、锑、铋、铜等在工艺流程中的分布率,摸清了有价金属主要分散情况。分析表明,金、银、硒、碲最大的分散点均为浮选尾矿,分别占分散总量的67%、37%、34%、58%,确定为重点管控对象。并结合统计分析结果对提高金、银、硒、碲回收率及铅、锑、铋、铜的回收提出了改进建议。

回收铜阳极泥冶炼渣中铑的研究

铜阳极泥冶炼渣是重要的铑资源,采用火法富集和湿法提取相结合的工艺对铜阳极泥冶炼渣中的铑进行回收利用,考察了火法富集过程中各种因素对富集效果的影响。结果表明:在PbO加入量为铜阳极泥冶炼渣的1.1倍(以质量计,下同)、B_(2)O_(3)加入量为铜阳极泥冶炼渣的1.1倍、Na_(2)CO_(3)加入量为铜阳极泥冶炼渣0.9倍、熔炼温度1 200℃,熔炼时间2 h的条件下,形成的铅合金中Rh含量达到7 536.4 g/t,富集6.2倍;在银粉加入量为铅合金的1倍、灰吹温度1 300℃、灰吹时间2.5 h条件下进行铅合金灰吹除杂富集,形成的银合金中Rh含量达到42 208.1 g/t,富集35.7倍;在浸出温度60℃、浸出时间1.5 h、浸出液固比为10∶1的条件下进行湿法提取,生产的铑粉纯度为91.2%,实现了铑二次资源综合回收。

高硒碲铜阳极泥协同高铜渣硫酸化焙烧工艺研究

高硒碲铜阳极泥在硫酸化焙烧过程中,产出的焙砂易烧结成大块状,且硒蒸出率较低。针对此问题,本研究利用高铜渣中单质铜含量高的特征,探索了铜阳极泥协同高铜渣硫酸化焙烧工艺,并进行了条件试验。试验结果表明,采用高铜渣协同硫酸化焙烧工艺处理铜阳极泥可行,在铜阳极泥与高铜渣质量比(以干重计)1∶0.1,硫酸与混合物浆化质量比0.85∶1,浆化时间60 min,四段焙烧温度分别为300℃、480℃、570℃、610℃,焙烧时间120 min等较佳工艺条件下,焙砂中硒含量可以降至0.1%以下。工业试验表明,产出的焙砂颗粒小且内部呈蜂窝状,铜阳极泥中硒得到有效蒸出,焙砂中硒平均含量由原来的6.67%降到0.09%,脱除率达98.65%。硫酸化焙烧过程中生成的粗硒纯度大于96%,可用于生产高纯度硒或者直接外售;生成的焙砂可通过球磨水浸分铜,分铜渣氯化分金回收金,分金渣氨浸分银回收银,最后将分银渣火法熔炼进一步回收有价金属。相较常规铜阳极泥硫酸化焙烧方法,本工艺实现了铜阳极泥中硒的深度蒸出,也实现了高铜渣的有效处理,具有推广价值。

分金液中金浓度对沉金工序的影响探讨

因某有色冶炼公司采用贵金属品位很低的进口铜精矿为原料,影响了后续铜阳极泥处理系统的贵金属回收。试验考察了终点电位和分金液金浓度对沉金工序的影响,得到较优的终点电位控制为270 mV,且将分金液返回分金工序进行氧化酸浸分金,每年可降低生产成本29.31万元。

回转窑处理铜阳极泥数值模拟

以湖北某铜阳极泥冶炼厂湿法处理工艺的生产数据和控制参数为支撑,基于硫酸化焙烧—硒回收的物理化学反应机理,采用冶金计算软件建立硫酸化焙烧、硒回收还原功能模块,模拟实际回转窑硫酸化蒸硒焙烧处理铜阳极泥生产过程。该模型采用的阳极泥数据具有代表性,且模型计算结果也与实际生产结果吻合,验证了该模型的有效性。