Characterisation of coarse composite sphalerite particles with respect to flotation

The flotation response of a typical zinc-lead (Zn/Pb) ore, with respect to coarse composite (sulphide/non-sulphide) particles is reported. The flotation tests were carried out on a selected feed particle size range (−600 + 75 μm, at P₈₀ of 390 μm) and the recovery of Zn composite particles analysed on a size by size basis. The best results were achieved with the use of 75 g/t sodium isopropyl xanthate (SIPX), obtaining a Zn recovery of 77%, with a significant improvement at the coarse end of the particle size distribution. Computerised scanning electron microscope (QEMSCAN) was used to characterise value mineral grain size and degree of liberation, as well as gangue and sphalerite association in particles reporting to both concentrate and tailings. A new characterisation function (Locking ratio, LR) was developed based on the data from the automated mineralogical analysis to characterise particles into two-phase composites with different degree of locking texture (simple and complex). The function, which is based on the mode of occurrence of sphalerite, grain size, proportion and composition of the constituent minerals in each particle, was used to study the flotation response of the particles with different degrees of locking. The results highlight the difference in recoverability of the sphalerite bearing particles with different degrees of locking, with simple locking texture giving higher recovery than complex locking texture, for the same overall liberation.     

Leaching of a zinc ore and concentrate using the Geocoat™ technology

In this study, the Geocoat™ technology was used for the extraction of zinc from a mineral concentrate obtained from the Kooshk mine (Yazd, Iran) by a culture dominated by the mesophilic bacterium Acidithiobacillusferrooxidans in a packed column bioreactor. A low grade sphalerite ore was used as support for the concentrate coating. During the 100 days of leaching pH, Fe³⁺, Fe^total, microbial population density and zinc extraction were measured. The final zinc extraction from concentrate and low grade support was 97% and 78%, respectively, and it was found that leaching from the support does not proceed significantly before leaching from the coating is completed.     

Impact of gypsum supersaturated solution on surface properties of silica and sphalerite minerals

In some sulphide mineral flotation operations, the process water contains high concentrations of calcium and sulphate ions that exceed the solubility limit of gypsum. It has been speculated that the gypsum supersaturated process water would lead to precipitation of gypsum which could coat on mineral surfaces by either nucleation or coagulation, resulting in reduced flotation recovery and selectivity. In this study, a laboratory prepared gypsum supersaturated solution is used to represent the gypsum supersaturated process water, the effect of gypsum supersaturated solution on the surface properties of silica and sphalerite minerals was investigated using zeta potential distribution measurements, scanning electron microscope (SEM), X-ray photon spectroscopy (XPS), Auger electron spectroscopy (AES), and quartz crystal microbalance with dissipation (QCM-D). Our results show that silica and sphalerite minerals carry identical surface charge (−10 mV of zeta potential) in the gypsum supersaturated solution at pH 10 although they are charged differently in simple electrolyte solution at the same pH. Needle shape gypsum precipitates are found in both silica and sphalerite minerals systems conditioned with gypsum supersaturated solution. The gypsum precipitates do not grow on the minerals surfaces but form in the bulk gypsum supersaturated solution. The heterocoagulation between the examined minerals and gypsum particles is insignificant in the gypsum supersaturated solution. It is the high calcium concentration in the gypsum supersaturated solution that has significant effect on the surface properties of silica and sphalerite minerals. The zeta potentials of silica and sphalerite in a 800 ppm calcium solution (similar to the calcium concentration in the gypsum supersaturated solution) are similar to those measured in the gypsum supersaturated solutions. Both silica and sphalerite minerals surfaces are indiscriminately coated with calcium. The surface coating of calcium results in the identical surfaces between silica and sphalerite minerals, and ultimately causes problems for the flotation separation of silica and sphalerite.     

Investigation of the effect of mineralogy as rate-limiting factors in large particle leaching

Although heap leaching is by now well established in the mining industry, the process remains limited by low recoveries with different rate-limiting factors that are not clearly understood. In this study, three large particle size classes (+19/−25, +9.5/−16, +4.75/−5 mm) were prepared from a sphalerite ore by two different methods of comminution (HPGR and cone crusher). The particles were then packed into leach reactors that were operated continuously for 11 months with well-mixed internal circulation of the leach solution. Characterization of the residue of the leach reactors indicated that there are areas within the ore particles where although sphalerite grains are accessible to the solution, they remain unreacted. X-ray tomography and QEMSCAN® analysis of the selected samples before, during and after leaching, showed increased leaching of sphalerite grains associated with pyrite due to galvanic interactions. Mineral chemistry (Fe, Mn content of sphalerite) and jarosite precipitation were also investigated as factors influencing sphalerite leaching.     

会泽铅锌矿方铅矿、闪锌矿和黄铁矿的浮游性研究

本文考查了ZnSO4和可溶性淀粉对方铅矿、闪锌矿和黄铁矿浮游性的影响，为会泽铅锌矿铅硫异步等可浮工艺提供了理论依据。试验结果表明，在乙黄药浮选体系中，ZnSO4和可溶性淀粉强烈抑制闪锌矿，而对方铅矿和黄铁矿的浮游性影响不大，且两者的浮游性相近。     

广东某闪锌矿选矿过程中铟的行为走向探讨

分析了广东某闪锌矿除富含Zn、S外，还富含稀散金属铟（In）。通过对不同选矿工艺流程及药剂制度下铟的跟踪分析，发现在不同的选别条件下，铟随着锌精矿而富集的行为走向。     

表面活性剂对锌精矿在浆萃取浸出率的影响

研究了几种不同的表面活性剂对锌精矿有机溶剂在浆萃取过程中锌浸出率的影响 ,并对表面活性剂的用量对锌精矿在有机溶剂中的行为进行了探讨 ,测定了经表面活性剂处理后矿粉在水溶液中的粘度以及浸出溶液表面张力变化情况 ,结果表明加入 0 .0 5～ 0 .2 g/L表面活性剂十二烷基磺酸钠改变了矿粉在水溶液中的润湿性 ,降低了浸出溶液的表面张力 ,有效地提高了锌精矿浸出率     

Editor's Introduction

This paper reviews the state of the art in processing and extraction of ocean floor manganese nodules. It briefly reviews the mining sites where the abundant rich nodules occur and also discusses the metal distribution in nodules in view of economical processing and extraction of these metal values.

The paper discloses in a detailed manner the physical and chemical characteristics of nodules, including porosity, surface area, water content and the effect of temperature on crystal structure of major constituents of nodules.

In the extraction aspect of nodules, the paper reviews two different extraction schemes revealed in the literature, namely hydrometallurgical treatment and pyrometallurgical treatment. The hydrometallurgical treatments include acid leaching, ammonia leaching, leaching with reducing agents and leaching after high temperature pre-treatments such as in sulfating rousting, while the pyrometallurgical processes include smelting, chlorination-vaporization and segregation. The paper also covers metal recovery processes from leach liquor.

An economic survey of processing nodules has been made in terms of problems associated with metal-marketing, and impact of metal production from nodules on mineral industries.     

西北某难选铅锌矿石浮选试验

西北某铅锌矿是一个矿物成分复杂、铅锌矿物分布极不均匀、嵌布粒度细微、嵌布关系复杂、单体解离难度大、脉石矿物硬度高的大型难选铅锌矿床。为确定该资源的开发利用方案,采用优先浮选工艺对该矿石进行了选矿试验。结果表明,在磨矿细度为-0.074 mm占85%的情况下,采用1粗1扫3精选铅(铅精选前再磨至-0.045mm占95%)、1粗1扫2精选锌、中矿顺序返回的闭路流程处理该矿石,可取得铅品位为60.45%、含锌8.90%、铅回收率为75.95%的铅精矿以及锌品位为51.60%、含铅0.31%、锌回收率为87.39%的锌精矿,该选矿工艺方案是该矿石的高效开发利用方案。     

由软锰矿,闪锌矿,铁屑直接制取锰锌铁氧体软磁材料新工艺研究

本文结合磁性材料工艺和锰矿技术特点，创造性地提出由软锰矿、闪锌矿制备锰锌铁氧体材料，克服了锰矿、闪锌矿处理过程的Ｍｎ－Ｚｎ、Ｍｎ－Ｆｅ、Ｚｎ－Ｆｅ分离难题，大大降低了磁性材料生产成本，由于磁性材料产品附加值高，从而为我国丰富的贫锰矿利用找到了一条有效的途径