氰化浸出-电积法从铜阳极泥提取金和银

采用硫酸化焙烧、稀硫酸浸出铜－－氰化浸出、电积提取Au和Ag－－还原熔炼回收Pb、Bi、Sn和微量Au、Ag工艺处理铜阳极泥，具有流程简短,回收率Au≥99%,Ag≥99%,Cu、Pb、Bi、Sn综合利用好等优点。     

四川丹巴铜炉房金矿床矿石选冶方法研究

通过多次对金矿石的选冶试验研究工作,使金精矿经沸腾焙烧预处理后Au、Ag、Cu、S的浸出回收率均得到显著提高,其中硫脲法Au、Ag、Cu的浸出率分别为99.4%、95.8%、98.0%;氰化法 Au、Ag、Cu的浸出率分别为:99.4%、89.4%、93.3%.最终确定矿石的最佳选冶方案为:原矿破碎→球磨→浮选富集→金、银、铜精矿→沸腾焙烧→烟气制硫酸,焙砂经硫酸浸出萃取电解回收铜后,再经硫脲法回收金银.     

氰化金泥处理过程产生的银渣中金、银的回收

为了回收金精炼氯化分金后生产银锭过程中副产品银渣中的金和银,对直接氰化及先酸溶再氰化处理效果进行了对比研究。结果表明,银渣经酸处理后,在优化条件下,其金浸出率可达95%以上,银浸出率可达90%左右,明显高于直接氰化;采用直接氰化处理方法,当银渣细磨至-0.038 mm占95%以上粒度时,氰化过程中加入碳酸氢铵,且氰化分段进行洗涤,延长浸出时间,可显著提高金、银浸出率。通过多次分段洗涤-氰化浸出工业试验,银渣中金回收率高达92.93%,银回收率84.17%。采用的方法操作过程简单,试剂消耗少,经济效益显著。     

金、银和铜氰化溶解速率及硫离子对其影响的比较

用旋转圆盘法在相同的实验条件下，对金、银、铜的氰化溶解速率进行比较研究。当氰化钠浓度为5．00g／L、圆盘转速为600r／min、温度为30℃时，获得表观速率常数的顺序为：Au〈Ag〈Cu。在氰化钠溶液中加入微量硫化钠后，硫离子抑制氰化反应的影响程度则为：Au〉Ag〉Cu。分析讨论了电化学反应机理，提出了相应的观点并对实验结果进行了解释。     

氰化金泥综合回收新工艺

氰化金泥中都含有Cu、Zn、Pb、Zg等有价金属,过去对金泥处理的最终产品是合质金。Ag、Cu、Zn、Pb不能单独回收,这不但浪费资源,而且对环境造成污染。本工艺解决了这些问题,Ag、Cu、Zn、Pb以不同的形式得以回收,Ag回收率＞96．5％,Au回收率＞99％。     

氰渣综合利用提取金银的试验研究

通过正交试验详细考察了矿浆浓度、硫酸过剩系数、反应温度和反应时间等因素对氰渣浸铁率的影响.结果表明矿浆浓度为35%、硫酸过剩系数为1.3、反应温度为100℃、反应时间为2.5 h的试验条件下,铁的浸出率最高,可达97.80%.对比氰渣和浸铁渣金、银的氰化浸出效果发现氰渣再氰化金、银的浸出率分别为5%和10%,而浸铁渣再氰化金、银的浸出率则分别高达87%和80%,因此氰渣浸铁再氰化是提高金、银回收率的有效途径之一.     

硫精矿中难选金银焙烧浸出研究

某高金硫精矿全泥氰化时金和银的浸出率低,一段焙烧预处理会造成金和银的二次包裹。实验结果显示,二段焙烧效果优于一段焙烧效果,能降低氧化铁的烧结程度,减少铁氧化物对金、银的包裹,金、银浸出率分别为79.86%、68.13%。添加剂实验结果表明,焙烧过程加入NaOH,银浸出率大幅提高;加入CaO有利于金的浸出;加入KMnO4能降低焙砂硫品位。以NaOH、CaO、KMnO4为组合焙烧添加剂,金、银浸出率提高至87.43%、85.86%。扫描电镜观察到,加入组合焙烧添加剂有利于焙砂孔隙度的提高,氰化尾渣表面腐蚀较为严重,有利于浸出剂与金、银的接触。 关健词:含金硫精矿;全泥氰化;二段焙烧;焙烧添加剂     

高杂质氰化金泥生产高纯金、高纯银实践

遂昌金矿针对高杂质氰化金泥采用的工艺为:硫酸加络合剂联合酸洗除铜锌、还原熔炼气氛下铅捕集金银生产银阳极板、一次银电解过程实现金银铅的分离、酸碱联合处理黑金粉、高酸低铜银电解生产工艺、非对称交流电源用于金电解生产等。该工艺生产的高纯银达99.996%以上、高纯金的质量稳定在99.997%以上,杂质含量远远小于高纯金(99.999%)的要求,流程操作简单,成品金银质量在国内处于领先地位。     

硫脲反萃金的研究

1.前言氰化法反应比较完全,回收率较高,成本较低,至今仍是金矿提金的最重要方法.但是氰化物毒性大,同时CN~-是强络合剂,可与Fe、Cu、Ni、Zn等许多贱金属络合,矿石组成复杂时试剂消耗大,金、银回收率降低.40年代国外开始研究硫脲溶金,我国70年代以来不少单位也进行了研究,兴起“硫脲热”.此法优点是浸出Au、Ag速度比氰化物快,络合选择性比CN~-高,同时毒性也比氰化物小,但由于经济原因一直未能用于工业生产.     

焙烧-氰化工艺处理含金硫精矿提高银回收率的研究

采用焙烧-氰化工艺处理复杂含金硫精矿时,银的回收率偏低,为了提高该过程银回收率,详细的研究了焙烧制度、焙烧料加添加剂、盐浸条件和氰化条件等对银回收率的影响。试验结果表明,焙烧过程中加添加剂和焙烧温度是影响银回收率的2个关键因素;提高银回收率适宜的条件为:焙烧时加入5%添加剂A,温度控制在450~500℃,所得焙砂经酸浸铜、盐浸铅后,在液固比2~3,氰化物质量分数0.4%,搅拌氰化24 h,弃渣含银40 g/t,银的总回收率81%。     

Enhancement of the photoluminescence of porous silicon by sputter deposition of semitransparent metal films

Optoelectronic devices based on porous silicon (PS) undergo substantial degradation in luminescence with aging due to atmospheric oxidation. The passivation of PS has been reported with a transparent conducting material or a semi-transparent metal. In this paper, we report enhancement of the photoluminescence (PL) of PS by the passivation of PS with ultrathin metal films such as silver (Ag), aluminum (Al), and gold (Au). It has been found that Ag and Au are respectively most and least effective in enhancing the PL of PS among those three different metals. The highest PL enhancing effect of Ag is mostly attributed to the high electrical conductivity of Ag, whereas the lowest PL enhancing effect of Au is due to the lowest optical transmittance of Au. The details of the PL enhancing effect of metal passivation are discussed with the aid of FTIR analysis results.     

New gold and silver-gold catalysts in the shape of sponges and sieves

Gold with a nanoporous sponge-like morphology, generated by leaching of AuAg alloys is presented as a new unsupported material system for catalytic applications. The role of residual silver for catalytic activity towards CO oxidation in the temperature range from −20 to 50°C has been investigated by comparison with Au and Au/Ag zeolite catalysts. As revealed by a systematic variation of the silver content in the zeolite catalysts, bimetallic systems exhibit a significantly higher activity than pure gold, probably due to activation/dissociation of molecular oxygen by silver. By STEM tomography we can unambiguously prove that at least some of the particles form inside the zeolite lattice.     

Impact of silver sulphides on gold cyanidation with polymetal sulphides

Gold leaching was influenced in association with silver and polymetal sulphide minerals. A packed bed was adopted to single out the galvanic and passivation effects with four sets of minerals: pyrite–silica, chalcopyrite–silica, sphalerite–silica and stibnite–silica. Pyrargyrite enhanced Au recovery to 77.3% and 51.2% under galvanic and passivation effects from pyrite (vs 74.6% and 15.8%). Pyrargyrite in association with sphalerite also enhanced Au recovery to 6.6% and 51.9% (vs 1.6% and 15.6%) under galvanic and passivation effects from sphalerite. Pyrargyrite associated with chalcopyrite retarded gold recovery to 38.0% and 12.1% (vs 57% and 14.1%) under galvanic and passivation effects. Accumulative silver minerals enhanced Au recovery to 90.6% and 81.1% (vs 74.6% and 15.8%) under galvanic and passivation impacts from pyrite. Silver minerals with sphalerite under galvanic and passivation effects enhanced Au recovery to 71.1% and 80.5% (vs 1.6% and 15.6%). Silver minerals associated with chalcopyrite retarded Au recovery to 10.2% and 4.5% under galvanic and passivation impacts (vs 57% and 14.1%). Stibnite retarded Au dissolution with pyrargyrite and accumulative silver minerals. Pyrargyrite and accumulative silver enhanced gold dissolution for free gold and gold associated with pyrite and sphalerite. Gold dissolution was retarded for gold and silver minerals associated with chalcopyrite and stibnite.     

金银合金真空分离的理论研究（英文）

为准确预测金银合金真空蒸馏过程中产品成分与温度和压力的关系,并为工业生产参数的设计提供便捷和有效的指导,根据分子相互作用体积模型(MIVM),计算不同温度下金银合金的分离系数(β)和气-液平衡成分。结合气液相平衡(VLE)理论,绘制金银合金真空蒸馏的温度-成分、压力-成分相图。同时,对金、银三相点和金、银蒸气冷凝温度进行计算。理论研究结果表明：随着蒸馏温度的升高,分离系数减小,金在气相中的含量增加;低温对分离金银具有积极效果;在压强1～10 Pa范围内,金、银冷凝温度相差约450 K。     

火试金重量法测定金碳基催化剂中金含量

采用火试金重量法测量含金碳基催化剂中金含量,通过焙烧温度、称样量、物料配比、金银质量比以及分金酸度等确定最优实验条件。在最优实验条件下通过加标实验,标准物质回收率99.0%~100.6%。方法准确度良好,可运用于实际生产分析。     

Ag/Au复合纳米粒子的制备

以柠檬酸化学还原法制备的金纲伙粒子作晶种,在光照的条件下Ag^ 被柠檬酸钠还原成金属银,而均匀地覆盖在金粒子表面,制成具有良好的分散性和较为规则的球形的银／金复合纳米粒子。研究了Ag/Au复合纳米粒子的紫外可见吸收光谱和共振散射光谱特性。     

常温氯化法从拜尔废催化剂中回收金钯

使用盐酸－氯气从拜耳废催化剂中回收金钯的工艺流程和流态化强化浸出设备,在常温下流态化搅拌,可快速一次浸出废催化剂中贵金属。在拟定的浸出条件下和使用一定浓度的浸洗剂清洗浸出渣,使催化剂中金钯浸出率＞98％,金属直收率＞97％。工艺及设备简单,成本低,适宜工业生产。     

《白色金合金标准样品》的研制

由于目前国内白色K金样品成分复杂、配方更新较快、缺乏可用于生产控制和检测工作使用的白色金合金标准样品,特别是含钯配方的标准样品。采用特殊的熔炼铸造工艺研制了主要成分为金、银、铜、锌、镍、钯、铟和铁等8种元素,金的质量分数范围为80%~37.5%的白色金合金标准样品。利用能量色散型X射线荧光光谱仪(XRF)、波长色散型XRF、电感藕合等离子体发射光谱仪(ICP-AES)和电位滴定仪等仪器设备对标准样品进行均匀性检验、稳定性测试、化学定值等,结果表明标准样品的均匀性和稳定性良好,定值准确,工作曲线线性良好。因此,该标准样品作为国家标准样品,可应用于白色金合金饰品的分析方法的确认及检测过程中的质量控制。     

Aggregation in thin-film silver: Induced by chlorine and inhibited by alloying with two dopants

The Ag aggregation mechanism triggered by chlorine (Cl) is discussed. The frontier orbital theory by K. Fukui is applied in order to determine the growing point in the silver (Ag) cluster. Ag in the thin-film silver would grow to Ag_nCl and stack, triggered by Cl from the outside according to the mechanism described. This would lead to an aggregate with a high Ag density. It is suggested that this would be the generating mechanism of the silver-gray aggregate consisting mostly of Ag, which is generated by exposing it to Cl.Two tactics in order to prevent restrain aggregation induced by Cl according to the mechanism are proposed. Tactic 1 is a restraining of structure change to a plane in the process of Ag₆Cl + Ag → Ag₇Cl. Tactic 2 is the trapping of Cl before it generates a bond to Ag.The ability of the two combined dopants with the abilities of tactics 1 and 2, such as in an Ag alloy including palladium and copper (APC), and including neodymium and gold (ANA) is expected to be very high. The aggregation resistance of an Ag alloy including two dopants is evaluated by a salt water immersion test. The APC and ANA demonstrated a very high resistance to Cl, because of the combination of the dopants working with tactic 1 (Pd, Au) and tactic 2 (Cu, Nd).The multilayer sputter coating with an ANA layer demonstrated a very interesting profile where the light transmittance and the electrical sheet resistance are almost the same as the multilayer sputter coating with a pure Ag. The multilayer sputter coating with AIS also demonstrates a very interesting profile, where the light transmittance is higher than the multilayer sputter coating with a pure Ag.