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。     

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.     

Characterization of refractory behaviour of complex gold/silver ore by diagnostic leaching

The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. ＜38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.     

含铜污泥还原熔炼过程金银捕集分布规律研究

含铜污泥还原熔炼过程产出金属铜相(Cu)和锍相(冰铜，mt)，铜、镍、金和银在两相中均有分布，统计了约100批次熔炼产品，分析其分布规律。结果表明，金、银在铜相中的分布系数(βAu Cu、βAg Cu)与铜在铜相中的分布系数βCu Cu呈正相关，说明铜相对金、银的捕集能力比锍强，且对金的捕集能力强于银；银分配系数LAg与铜、镍在铜相中的分布系数(βCu Cu、βNi Cu)呈正相关，金、银分配系数(LAu、LAg)与锍相中镍含量([Ni]mt)均呈弱负相关，说明锍相对银的捕集能力强于金。     

化学和物理分离法萃取金、汞、银

采用搅拌过滤法对Aghdareh金矿样品进行金的萃提。矿物学研究表明, 样品中58%的金颗粒小于10 μm,该等级的3%属于难熔金。实验结果表明, 在最优条件下,金回收率可达91.8%, 银和汞分别为41.5%和10.2%。以氰化法测试的6种分次尺寸样品的结果表明,未萃取的金粒子大多小于25 μm,还有大约5%的金颗粒大于25 μm。因此, 对样品要进一步粉碎,这样可使金和银回收率分别提高约3.57%和约5%, 进一步粉碎样品并不影响汞的回收率。采用Knelson重力选矿法可提高汞回收率并防止金和汞的混合,利用氰化法检测重力法的尾料。这些方法的结合应用, 最终使金回收率达到93.3%, 汞回收率增加到42.16%, 而银回收率没有明显的变化,为42.17%。     

预浸-氰化浸出回收湿法炼锌渣中的银和金

某冶炼厂的锌浸出渣中银勘布粒度细,含银、金分别为381.3、1.02 g/t,可采用预浸-预浸渣氰化浸出工艺回收。重点研究了预浸条件对银、金浸出效率的影响。条件实验表明,药剂A比酸浸、氨浸具有更好的预浸效果;最佳预浸条件为药剂A浓度200 g/L、浸出液固比2:1、在50℃浸出3 h。综合条件实验得到的预浸渣渣率为66.2%,金、银的氰化浸出回收率分别为85.7%、92.9%。     

Co-intensification of gold leaching with heavy metals and hydrogen peroxide

Co-intensification was researched to accelerate gold leaching with regards to its electrochemical nature by using anodic intensifiers of heavy metal ions (Pb2+, Bi3+, Tl+, Hg2+ and Ag+) on the basis of hydrogen peroxide assistant leaching on three different types of materials which were classified as a refractory sulphide gold concentrate, an easily leachable sulphide gold concentrate, and a low grade oxide gold ore according to their leaching characteristics. The results showed that, favorable co-intensification effects on the three materials were obtained and leaching time of gold was effectively shortened to no longer than 12 h from 16 to 24 h for hydrogen peroxide assistant leaching. For the five tested heavy metal ions, Bi3+and Tl+ presented co-intensifying effect on all the three materials, and Hg2+ caused co-intensifying effect on both refractory and easily leachable sulphide gold concentrates, and Pb2+ and Ag+ only had co-intensifying effect on the easily leachable sulphide gold concentrate.     

难冶金精矿焙砂和烟尘氰化浸金的差异（英文）

采用对比方法研究难冶金精矿焙砂和烟尘氰化浸金的差异。结果表明,直接氰化时焙砂和烟尘中金的浸出率分别为85.31%和54.30%。砷、碳含量及其存在形式是导致两者金浸出率差异的主要原因。对于NaOH预处理后氰化浸金,焙砂和烟尘中金的最大浸出率分别为87.70%和58.60%。有害元素的脱除、碱浸预处理过程中金的损失及铁氧化物的阻碍共同决定碱浸预处理后焙砂和烟尘中金的浸出率。经H₂SO₄预处理后,焙砂和烟尘中金的最大浸出率分别达到94.96%和80.40%。碳质物的影响是焙砂和烟尘中金浸出率差异的主要原因。基于这些差异,提出两种适宜工艺,焙砂和烟尘中金的浸出率分别达到94.91%和91.90%。     

从铅银渣中回收金银概况

为实现铅银渣中金银的综合回收,对铅银渣物理化学性质、有价金属含量、赋存状态、铅银渣中金银的回收方法、研究进展及其应用情况进行综述。铅银渣粒度细、酸度强、可溶物含量高,渣中矿物经历过相体转化由硫化物转变成氧化物,以再造矿物形式存在,选矿难度大;铅银渣有价金属铜、铅、锌、金、银含量较高,经济价值可观。目前,从铅银渣中回收金银的主要方法为浮选法、湿法、火法、湿法-火法联合、选冶联合等。通过分析各种方法优缺点,指出单一的浮选法流程简单、成本低,但金银回收率低;湿法、火法或湿法-火法工业应用良好,但是存在工艺复杂、成本高;选冶联合方法金属回收率高、流程适应性强,便于连续操作,具有较好的发展应用前景。     

难选氧化金矿氰化助浸试验研究

甘肃某金矿中金属矿物含量较少,以褐铁矿、黄铁矿为主,脉石矿物主要有石英、粘土矿物等.探索试验表明氰化浸出获得指标明显优于浮选、重选法.采用助浸剂可以提高金的氰化浸出率,其中混合助浸剂HZ可同时降低氰化钠用量,缩短浸出时间.采用优化工艺条件,在磨矿细度-74μm占90％,石灰用量3000 g/t,矿浆浓度40％,混合助浸...     

难冶金精矿烟尘中铁砷碳的脱除对氰化浸金的影响

以难冶金精矿烟尘为原料,研究了氢氧化钠浸出、硫酸浸出以及硫酸与氢氧化钠联合浸出对烟尘中砷、铁和碳脱除及氰化浸金的影响。结果表明:在氢氧化钠浓度为6mol/L时,砷、碳脱除率分别为99.66%和60.63%,金浸出率为58.90%,较直接氰化浸出仅提高4.60%,砷的有效去除不能有效提高金的浸出率。在硫酸质量分数为15%时,铁、砷和碳脱除率分别为33.65%、80.38%和12.59%,金的浸出率为80.40%,与氢氧化钠浸出相比,硫酸浸出解离铁能有效提高金的浸出率。烟尘分别经过质量分数为15%硫酸浸出后氰化浸金,两次2 mol/L氢氧化钠浸出和氰化浸金后,烟尘中铁、砷和碳的总脱除率分别为33.65%、95.63%和79.60%,渣率为80.33%。此时,金的总浸出率为91.90%,氰化渣中金的含量为3.31g/t。与烟尘直接氰化浸出相比金的浸出率提高37.60%。     

用铁粉置换回收氰化金泥精炼废水中的金和银

采用铁粉置换处理山东黄金冶炼有限公司氰化金泥精炼废水,考察了铁粉用量、pH值、反应温度和置换时间等因素对金、银置换率的影响.条件实验确定的最佳工艺技术条件为:保持原液pH=0.5,铁粉用量2.5 kg/m3、反应温度60℃、置换时间30 min,金和银的置换率在95％和97％以上;在工业应用中银的置换率进一步提高到98...     

难处理金矿预处理及金回收技术进展

随着优质金矿不断被开发消耗,难处理金矿占比不断地提高,从难处理金矿中回收金是金产业未来发展的必然趋势。本文简要分析了难处理金矿浸出困难的原因,介绍了焙烧氧化法、热压氧化法、生物氧化法、机械活化法、微波法5种预处理技术和氰化法、硫脲法、硫代硫酸盐法、卤素法、火法5种金回收技术的研究进展,并比较了5种预处理技术和4种湿法金回收技术的优势与不足。在此基础上对难处理金矿预处理和金回收技术的前景进行了展望。     

Investigation of the tarnish on the surface of a panda gold coin

In natural environment, tarnish was observed on the surface of historic and contemporary gold coins in several countries. Few years after the emergence of panda gold coins, several red spots were appeared on the surface. To identify the stains and to examine the spots, optical microscope （OM）, scanning electron microscope （SEM）, electron microprobe analysis （EMPA）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD） were used. It was found by microscopic observation that the stain has a dark blue central area surrounded by a large area with a nuance of colors from brown to red. Red spots usually contain holes in the center, which are distributed along the forging stress zones formed in the struck process. From the surface analyses using EMPA, sulfur and silver are detected besides gold, and the contents of Ag and S at the tarnish part are higher than those at the other part. Furthermore, distributions of Ag and S are correlated with the morphology of stains. XPS shows that components of stains are Ag2S and Ag2SO4 and the former is much predominant. These results are confirmed using XRD analysis. Accelerated tarnish test of gold in an atmosphere containing sulfur compound proves that the similar phenomenon appears when a small amount of silver is present on the surface of gold. It can be concluded that the occurrence of tarnish stains is caused by the presence of Ag and S.     

紫金山铜金矿中金铜银的赋存状态研究

采用矿物自动分析仪(MLA)、扫描电镜(SEM)、X射线衍射(XRD)研究了紫金山金铜矿入选矿石中有价元素铜、金、银的赋存状态以及分选过程中的金属走向。结果表明,铜矿物主要有蓝辉铜矿、铜蓝、硫砷铜矿,金银以游离矿物和硫化物包裹体为主。铜矿物常见沿明矾石溶蚀孔洞或碎裂缝隙充填,与黄铁矿密切连生,从原矿中分选铜矿物,理论品位为Cu 69.70%,理论回收率93.55%。中粒金嵌布于铜矿物和黄铁矿矿物粒间或裂隙,可随着铜和硫的回收进入铜、硫精矿,金的理论回收率分别为57.19%和27.27%;微细金粒包裹于明矾石和石英中,随脉石损失于尾矿中。银以显微银为主,多见呈微细粒包裹于硫化矿物中,铜精矿和硫精矿中银的理论回收率分别为56.96%和26.71%。     

Preparation of nanostructure silver powders by mechanical decomposing and mechanochemical reduction of silver oxide

The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to characterize the structural evolution and morphological changes of products. The results show that the nanostructured silver with an average crystallite size of 14 nm and internal strain of 0.75% is synthesized by mechanical decomposing of Ag₂O after 95 h milling. While, the product of mechanochemical reduction of silver oxide using graphite after 22 h milling is nanostructured silver with an average crystallite size of 28 nm and internal strain of 0.44%.     

电镀软金用硫基无氰金配合物电解质研究进展

电镀金工艺中金氰化物([Au(CN)2]-)溶液在过程中会释放出剧毒的游离氰化物离子,严重危害到生产人员和自然环境的健康;此外,它们还会对光刻胶造成一定的破坏.近年来无氰电解质得到了发展.基于对50余篇文献的分析,本文比较了亚硫酸金([Au(SO3)2]3-)、硫代硫酸金([Au(S2O3)2]3-)和二者混合电解液,...     

银餐具中银迁移量的影响因素研究

根据银餐具的预期使用方式,选取不同食品模拟物及实验条件,用电感耦合等离子体发射光谱法(ICP-AES)对银内胆水杯中银迁移量进行测试。测试结果表明,银迁移量主要受浸泡时间、温度和酸度影响。在长时间浸泡、较高温度、酸性或茶水实验条件下,银内胆水杯中均可迁移出较多银离子,超过饮用水国家标准中对银离子限量(0.05 mg/L)的规定,在餐具安全评价中应予重视。     

草酸银中银的还原重量法测定

采用水合肼还原重量法测定草酸银中银含量,平行测定5次,测定的相对标准偏差小于0.04%,加标回收率99.96%～100.02%,干扰试验显示：0.1 mg的Zn²⁺、Co²⁺、Ni²⁺、Cu²⁺、Cd²⁺不干扰银的测定。该法与其他方法相对比,样品取样量大,操作简单,可满足生产现场测定的要求。