Enhance Cyanide Recovery by UsingAir‐Sparged Hydrocyclone

Human health and environmental concerns dictate that industrial processes be improved or replaced. Recovery or recycling is an important activity that allows cyanide residue from the industrial processes to be re‐used, reducing its production cost and disposal problems. In this regard, the air‐sparged hydrocyclone (ASH) has been used as a reactor for the treatment of cyanide solutions for cyanide recycling by acidification/volatilization using the Mexican modification of the Mills‐Crowe process. Aqueous cyanide‐ion concentration can be reduced from 250 ppm to below 20 ppm in the ASH with recoveries greater than 80 % in a single stage.     

Silver electrodeposition from air and water-stable ionic liquid: An environmentally friendly alternative to cyanide baths

The influence of temperature on the kinetics and the morphology of silver deposits obtained from an air and water-stable ionic liquid (the 1-butyl-3-methyl imidazolium tetrafluoroborate) was studied by means of cyclic voltammetry and chronoamperometry. The nucleation and growth mechanisms have been investigated and the effect of temperature evaluated up to 200 °C. Dense, pure and very thin (about 0.3 μm) silver coatings, with decorative properties, have been obtained on commercial copper electrodes at different temperatures. The characterization of the deposits morphology has been performed by visual investigation and SEM microscopy. Data about thickness were acquired by Calotest® measurements. The deposits result constituted by pure silver as determined by combination of EDX microanalysis and Auger Electron Spectroscopy (AES). The deposition method promises to be a new, environmentally friendly, method for silver electrodeposition which is the reason for the absence of cyanide and volatile toxic solvents in the electroplating bath.     

SFG and DFG investigation of Au(111), Au(210), polycrystalline Au,Au–Cu and Au–Ag–Cu electrodes in contact with aqueous solutions containing KCN and 4-cyanopyridine

We report on potential-dependent in situ SFG and DFG spectroscopy carried out at Au(111), Au(210), polycrystalline Au, Au–Cu and Au–Ag–Cu electrodes in contact with aqueous solutions containing CN⁻ and 4-cyanopyridine (4CP). Spectroelectrochemical work was complemented by cyclic voltammetry. The chief stress has been placed on systematising and quantifying the interaction between 4CP and CN⁻ and the attending effects on the vibrational and electronic structures of the interface. The voltammetric behaviour of the investigated electrodes, modified by the addition of 4CP to the CN⁻ electrolyte, denote changes in the CN⁻ adsorption characteristics and effects of the adsorbed CN⁻ layer on the electrodic reactivity of 4CP. The differences among the investigated electrodes can be explained in terms of their respective degrees of atomic packing or with alloying effects on the stability of adsorbed CN⁻. The potential-dependent spectra have been analysed quantitatively with a model for the second order non linear susceptibility accounting for vibrational and electronic effects. The spectral changes induced by addition of 4CP denote interaction of the aromatic with the electrode through the CN⁻ monolayer. The non-resonant contribution yields information on the effects of 4CP on the fine structure of the bound electron density of states.     

Suppression of photo-induced dilation in cyanide treated hydrogenated amorphous silicon films

Effects of cyanide (CN) treatment with hydrogenated amorphous silicon (a-Si:H) films have been investigated. The decrease of ΔV/V was observed in cyanide treated a-Si:H films and the successive thermal annealing at 200°C after CN treatment induced the further reduction of the ΔV/V. XPS spectra show the indirect evidence that the cyanide species is present within 10 nm from the hydrogenated amorphous silicon surface. The results of CN treatment with a-Si:H solar cells are demonstrated.     

Belgian Experiences in the Ozonization of Water

After reviewing the uses of ozone in the preparation of drinking water, high purity water for Pharmaceuticals industries, and swimming pools throughout Belgium, a discussion of technological developments made at the Tailfer plant (serving Brussels) concerning the uses of ozone is presented. These subjects include analytical and monitoring techniques developed for ozone, procedures for ozone contacting employed at this plant, treatment of ozone contactor off–gases, and the use of oxygen–enriched process gas to produce supplemental amounts of ozone required periodically. Capital and operating cost data are presented.     

几座移动式选金厂的生产效果

三年前,地矿部矿产综合利用研究所研制成功移动式选金装置,并设计建成了一些移动式选金厂,取得了良好结果。本文介绍了几个处理量为10—50t/d移动式选金厂的运行状况,着重讨论了所处理的矿石性质、工艺流程及获得的生产技术指标或设计指标。     

过氧化氢在氰化浸金工艺中的应用

本文综述了过氧化氢辅助浸金工艺的发展现状。进行了两个矿样的小型试验。结果表明,使用过氧化氢辅助浸金,可缩短浸出时间,提高金的浸出率。     

氧化金矿石强化氰化浸出的试验研究与工业实践

针对某氧化金矿石的特性,提出采用"过氧化钙强化氰化浸出工艺"进行处理,实验室研究获得最佳浸出条件为:浸出物料细度-74μm占93%,浸矿浓度为35%,NaCN用量为4 kg/t,石灰用量8 kg/t,过氧化钙(CaO2)用量为4kg/t,木质素磺酸钙(SAA)用量为1 kg/t,矿浆pH值为12.3左右。过氧化钙强化氰化浸出工艺的工业生产实践表明,与原工艺相比,金、银的浸出率明显提高,经济效益十分明显。     

某低品位氧化型金矿可选性试验研究

该金矿为低品位氧化型金矿。通过活化含金矿物,使其成为浮游性较好的矿物形态,再经浮选富集,金精矿品位达到21.75g/t,回收率78.46%。浮选精矿产品直接氰化浸出,金浸出率达到97.62%;金选冶总回收率76.59%。采用浮选氰化浸出的选冶联合方案,可使同类型低品位金矿资源的综合开发利用成为可能。     

某银精矿氰化尾渣中铅和锌的浮选回收试验

某浮选银精矿经常温常压碱式氧化预处理-氰化浸出金、银后的氰化尾渣中,含有铅、锌、金、银等有价元素,金属矿物主要为黄铁矿、方铅矿、闪锌矿和毒砂,并含有少量含银矿物。该尾渣粒度很细,含泥量大,铅、锌矿物被氧化,使铅、锌的选别回收受到影响。对该尾渣进行铅、锌的浮选试验,结果表明,铅矿物不能得到有效富集而形成铅精矿,但可以获得锌品位为55.62％,锌回收率为66.15％的合格锌精矿,锌精矿中金、银品位为66.94 g/t和538.9 g/t,金、银回收率为47.96%和25.67%。