氨性催化氧化-氰化法处理含砷难浸金矿的研究(Ⅱ)

本文概述了氨性氧化-氰化法处理含砷难浸金矿的扩大实验结果．对于含有砷、锑、汞、碳的丹寨金精矿，其金品位为17．6g／t，金的氰化率可达84％与小型实验结果相符．     

化学氧化强化湿法冶金清洁生产：进展与展望

湿法冶金具有能耗低、污染小等优点，广泛应用于低品位复杂矿石处理。金属浸出是湿法冶金的首要环节，但存在金属回收率低和反应时间长等问题。化学氧化可加速金属硫化物转化为金属离子或改变金属的价态，有利于后续目标金属的分离富集，在此过程中还可以通过介质强化、外场强化提高金属氧化浸出率。主要介绍了五种典型的低腐蚀性化学氧化剂(Fe3+, O2, H2O2, O3和过硫酸盐)，以及相关的协同氧化方法在金属浸出中的应用和机理分析，介绍了加压强化、介质强化、微波和超声等强化方法，对比分析了各方法的优缺点及适用范围。Fe3+广泛应用于硫化矿的酸性浸出，独特的离子对循环使Fe3+可与多种氧化剂形成协同氧化浸出机制。O2常通过加压强化提升氧化浸出效率，可促进难处理硫化矿氧化分解。H2O2氧化性强，氧化产物清洁无污染，受到广泛关注，近年来多用于电子废弃物资源处理领域。臭氧预氧化处理含硫含砷难处理金精矿，可有效解除难浸硫化矿对金的包裹，促进金的溶出。过硫酸盐性质稳定，氧化能力强，可活化生成更高氧化性的活性氧。协同氧化可结合各氧化剂的优点，提高氧化能力，降低综合成本。四种强化方法可为化学氧化过程提供能量、加强传质或提高金属分离选择性，有助于提高金属浸出率，缩短反应时间。展望了化学氧化强化金属浸出技术的发展前景和技术挑战，对湿法冶金清洁生产技术开发有指导意义。     

难处理金精矿含元素硫的酸浸渣加石灰氧压浸金

实验研究了难处理金精矿含元素硫的酸浸渣加石灰氧压浸金过程，论述了石灰加入量、浸出时间和浸出温度对浸金的影响规律，发现最佳石灰加入量应使浸渣中元素硫与OH的摩尔比为0.8~1.1，在85°C和0.1~0.3 MPa氧压下浸出3~5 h，金的浸出率可达90%，此时终pH在5~8范围内. 根据实验结果分析，推断浸出过程中元素硫在一定pH值范围内氧化生成的S2O32–是主要的浸金剂.     

电子束辐照降解氰化浸金废水的研究进展

电子束辐照处理废水技术具有能处理众多难降解、高毒性污染物,适应性广泛,不产生二次污染,安全可靠等优点。浸金废水是高毒性含氰废水,锌氰络合物是浸金废水中的主要成分之一。通过电子束辐照锌氰络合物水溶来模拟电子束辐照降解浸金废水研究,研究了不同初始浓度、不同辐照剂量下的辐照效应,分析了电子束辐照降解浸金废水的可行性及存在的问题,并展望其应用发展前景。     

国内外金矿中金的浸出技术研究现状

介绍了从金精矿中提金的主要方法，包括氰化法(炭浆法、炭浸法、树脂法、生物氧化法)和非氰化法(硫脲法、硫代硫酸盐法、卤素法等)。总结了氰化法提金和非氰化法提金方法的基本原理和工艺特点。另外，本研究还对每种方法的优缺点进行分析和比较，为今后研制出既高效又清洁的提金方法提供了重要的理论依据。     

氨性催化氧化-氰化法处理含砷难浸金矿的研究(Ⅰ)

本文提出的氨性催化氧化－氰化法处理含砷难浸金精矿新工艺，其特点是在氨性溶液中以Cu2＋作催化剂，O2作氧化剂，在85℃及200kPa的操作压力下，将毒砂氧化，使其中的金游离出来，固液分离后再进行CILO氰化．对于含有砷锑汞碳的丹寨金精矿，其金品位为16.5～22g／t；金的氰化率可达80～87％.     

染料废水的高级氧化处理技术研究进展

染料废水主要来源于制革、纺织、食品、造纸、塑料等行业,具有有机物浓度高、成分复杂、色度高、难降解等特点。高级氧化法在处理有机废水具有鲜明的亮点,本文综述了染料废水的高级氧化处理技术研究进展,对臭氧氧化法、电化学氧化法、催化氧化法和物理氧化法四种方法进行了归纳和总结了其优缺点,且对染料废水处理的高级氧化法研究发展进行了展望。     

难选冶矿黄金冶炼工艺和技术

介绍了当前国内外难选冶矿黄金冶炼工艺、技术和实验研究,对包括目前较为成熟的沸腾 焙烧、两段焙烧、生物预氧化、热压氧化、化学氧化等金精矿预处理工艺进行了比较,并对氰化法工艺、金精炼工艺和其它金浸出药剂工艺的研究分别进行了论述.最后对难选冶矿金回收研究应用的前景和方向进行展望.     

次氯酸钠一步法浸金的原理与试验研究

用E－pH图和Gibbs自由能分析了以次氯酸钠为浸金剂一步法浸金的原理和浸出条件,用广西贵港六梅含砷金精矿进行试验,研究了浸出条件对浸出率的影响,提出了优化的工艺条件,实验表明,用次氯酸钠对含砷难浸金矿进行一步法浸金是可行的。     

物化法处理印染废水的研究进展

印染废水由于含有大量难生物降解有机物,且色度极高,单独的生物法难以对其有效处理。综述了近几年来国内外采用吸附、混凝、膜分离等物理方法和光氧化、电氧化、湿式氧化、Fenton氧化、微波诱导、超声催化氧化等化学氧化技术处理印染废水的进展情况和优缺点,并指出物化法与生物法相耦合将是处理印染废水经济有效的工艺。     

Recovery of gold in iodine-iodide system – a review

Gold leaching in iodine-iodide solution has been intensely researched in 1980s; while due to the high cost, it has not been applied in industry. Currently, as the drawbacks of other hydrometallurgies appearing such as aqua regia and cyanidation, mining and exploration companies are shifting their attention to the iodide leaching, because which has low electrode potential, fast leaching kinetics, high leaching rate, mild reaction conditions and the lixiviant is easy to recover. The common gold leaching agents, although considerable researches have been undertaken, most, if not all, of which have been proven to have limitations that hinder their widespread adoption in the gold mining industry. Iodide leaching could serve as an effective mean for recovering gold through the dynamic, thermodynamic and electrochemical assessment. And a series of parameters, such as oxidants selection, the iodine/iodide ratio, solid-to-liquid ratio, acidity (pH) and leaching time, affect the gold leaching efficiency. Through a comparison with several other hydrometallurgical processes, the presenting merits promote iodine-iodide system to be a promising method for gold recovery. The key challenge of industrialization is how to reduce the cost and to recover gold from the lixiviant.     

高海拔地区难处理金精矿的细菌氧化预处理及氰化浸金

针对高海拔地区某难处理金精矿含砷高的特点,采用细菌氧化预处理工艺,考察在一定工艺条件下,Fe, S, As脱除率及金的氰化浸出率,并对金精矿及氧化渣、氰化渣进行了分析. 结果表明,Fe, S, As脱除率均达85%以上,金氰化浸出率为88.09%,说明对该类矿物采用细菌氧化预处理工艺具有可行性. 机理分析表明,细菌氧化金精矿是通过直接与间接协同作用机理;氧化酸液中和主要是将液相中砷以化学性质稳定的砷酸铁沉淀除去,将重金属离子等以氢氧化物沉淀去除.     

提高金山地表氧化矿堆浸金浸出回收率的措施

为提高金山地表氧化矿堆浸金提金回收率．本文分析了堆浸浸出率的几大影响因素,提出了改进的办法和措施．使生产实践中的堆浸浸出提金回收率得到了大幅提高。     

Leaching Gold Using Oxidation Products of Elemental Sulfur in Ca(OH)2 Solution Under Oxygen Pressure

A gold leaching process by using in situ oxidation products of added elemental sulfur in Ca(OH)2 solution was investigated. A gold concentrate containing 45 g/t Au was tested and 85%~87% of gold were leached. The leached gold depends mainly on the initial molar ratio of elemental sulfur to the hydroxyl ion, the consumption of oxygen and the reaction temperature. Adding some surfactants, such as lignosulfonic calcium, at lower concentration increased the leached Au but at higher concentration decreased it. Both of thermodynamic analysis and experimental results show that thiosulfate is the major complexing agent for gold in the process.     

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

The interaction of gold atoms with CeO₂ nanocrystals having rod and cube shapes has been examined by cyanide leaching, TEM, TPR, CO IR and X-ray absorption spectroscopy. After deposition?Cprecipitation and calcination of gold, these surfaces contain gold nanoparticles in the range 2?C6 nm. For the ceria nanorods, a substantial amount of gold is present as cations that replace Ce ions in the surface as follows from their first and second coordination shells of oxygen and cerium by EXAFS analysis. These cations are stable against cyanide leaching in contrast to gold nanoparticles. Upon reduction the isolated Au atoms form finely dispersed metal clusters with a high activity in CO oxidation, the WGS reaction and 1,3-butadiene hydrogenation. By analogy with the very low activity of reduced gold nanoparticles on ceria nanocubes exposing the {100} surface plane, it is inferred that the gold nanoparticles on the ceria nanorod surface also have a low activity in such reactions. Although the finely dispersed Au clusters are thermally stable up to quite high temperature in line with earlier findings (Y. Guan and E. J. M. Hensen, Phys Chem Chem Phys 11:9578, 2009), the presence of gold nanoparticles results in their more facile agglomeration, especially in the presence of water (e.g., WGS conditions). For liquid phase alcohol oxidation, metallic gold nanoparticles are the active sites. In the absence of a base, the O?CH bond cleavage appears to be rate limiting, while this shifts to C?CH bond activation after addition of NaOH. In the latter case, the gold nanoparticles on the surface of ceria nanocubes are much more active than those on the surface of nanorod ceria.     

Mineral phase and structure changes during roasting of fine-grained carbonaceous gold ores and their effects on gold leaching efficiency

While roasting has been widely applied to reduce the negative effect of carbonaceous matters on gold extraction from fine-grained carbonaceous gold ores, the phase and structure changes of minerals during roasting and their influences on the leaching rate of gold have not been fully understood. This limits the extraction of carbonaceous gold deposits. The current work examines the oxidation process of a fine-grained carbonaceous gold ore during roasting using a range of techniques including X-ray diffraction(XRD), scanning electron microscopy(SEM),Energy Dispersive Spectrometer(EDS) analysis and pore structure analysis together with gold leaching tests.The results show that during the process of oxidative roasting, the carbonaceous matters(organic carbon and graphitic carbon) and pyrite were completely decomposed at 600 ℃ with the carbonaceous components burned and pyrite oxidized into hematite. At 650 ℃, while dolomite was decomposed into calcia, magnesia, calcium sulfate etc., the calcine structure became loose and porous, leading to a high gold leaching rate from the roasted product. Above 750 ℃, the porous calcite structure started to collapse along with the agglomeration, leading to the secondary encapsulation of gold particles, which contributed to the sharp drop in the gold leaching rate of the roasted product. This study suggests optimum phase and structure changes of minerals during roasting to achieve maximum gold extraction from fine-grained carbonaceous gold deposits.     

石灰湿法加压氧化预处理含砷金矿的研究

本文研究了加压氧化法预处理含砷金矿，由于加入木质素磺酸钠作表面活性剂，从而成功地用石灰乳液作为碱性物料预氧化含砷难冶金矿，获得金的氰化浸出率在85％以上     

高稳定性碱性硫脲体系对不同类型金矿的适应性

为考察碱性硫脲体系对不同类型金矿浸出的适应性,选用理化性质不同的6种含金物料,分析了其化学组成及矿物物相,并对其浸出行为进行了研究. 结果表明,稳定剂Na2SO3和Na2SiO3大大降低了碱性硫脲的分解率,随稳定剂浓度的增大,硫脲分解率逐渐降低;而且Na2SiO3对碱性硫脲的稳定效果明显优于Na2SO3,当Na2SiO3浓度为0.3 mol/L时,硫脲的分解率由72.5%降至33.8%. 铁氰化钾为适合碱性硫脲浸金的温和氧化剂. 碱性硫脲体系中金矿物浸出前后物相基本无变化. 所选择的金矿物中均含有大量耗碱物质,使溶液的pH值由12.5很快降至中性,但稳定剂Na2SiO3能维持体系的pH值在12左右,有利于浸出过程的进行. 碱性硫脲体系中伴生金属浸出率小于0.1%,浸金具有显著的选择性. 碱性硫脲体系适合浸出经预处理的物相主要为SiO2的氧化矿,浸金率高达82.68%,为碱性硫脲成功应用于黄金工业生产提供了一定的理论依据.