A laboratory study of covers made of low-sulphide tailings to prevent acid mine drainage

Covers with capillary barrier effects (CCBE) are considered to be one of the most effective ways to control acid mine drainage (AMD) production from mine wastes. The use of low-sulphide tailings in CCBE has been proposed recently for cases where other types of material may be unavailable near the mining site. This paper presents leaching column test results showing that CCBEs with a moisture-retaining layer made of slightly reactive tailings, with three different sulphide contents, can effectively limit the production of AMD from the acid-generating tailings placed underneath. With these layered covers, the leachate pH was maintained near neutrality throughout the testing period. When compared to uncovered tailings, the efficiency of the cover systems for reducing the amount of contaminants in the percolated water was determined to be greater than 99% for zinc, copper and iron. This study shows that the use of low-sulphide tailings can improve the ability of a CCBE to limit gas diffusion by consuming a fraction of the migrating oxygen.     

Interaction of thionocarbamate and thiourea collectors with sulphide minerals: a flotation and adsorption study

The ability of O-isopropyl-N-ethyl thionocarbamate (IPETC), O-isobutyl-N-ethoxycarbonyl thionocarbamate (IBECTC) and butyl ethoxycarbonyl thiourea (BECTU) collectors to increase the flotation of the sulphide minerals, chalcopyrite, galena and pyrite, has been studied. For each collector, the flotation characteristics of these minerals, flotation rate constant and flotation recovery maximum, have been calculated from the flotation data and compared as a function of pH and collector concentration. Overall, the flotation performance of these collectors is stronger for chalcopyrite than for galena and pyrite. Flotation increases with collector concentration and decreasing pH values. For chalcopyrite, the collector performances of BECTU are slightly better than those of IPETC but far superior to those of IBECTC, especially at high pH values or at low collector concentrations. The flotation performance of these collectors has been shown to be in good agreement with the amount of collector adsorbed at the mineral surface. The affinity of BECTU for the various minerals has been calculated using a multilayer adsorption model.     

Heavy metals speciation analysis as a tool for studying mine tailings weathering

A sequential extraction procedure derived from Tessier et al. (1979) was applied in the area west of Montevecchio to abandoned mine tailings which give rise to a neutralised drainage highly contaminated by heavy metals. The results were compared with mineralogical studies of the weathering processes. The proposed sequential extraction procedure confirms the general alteration modalities observed in the area through mineralogical studies: i.e., a relatively easy dissolution of Zn and Cd and strong immobilisation of Fe, Mn, Cu and Ni. The behaviour of Pb and Co is intermediate.A generalization of a chemical approach to the comprehension of the weathering process is outlined, though an improvement of the methodology should include a more appropriate sequential extraction procedure capable of distinguishing siderite from iron oxyhydroxides, of leaching anglesite in a single step and of including calcium and magnesium among the analysed elements because of the role of their carbonates in buffering the drainage.     

石英与钠长石浮选分离的研究

用十八胺(阳离子捕收剂)和十二烷基磺酸钠(阴离子捕收剂,SDS)作浮选为捕收剂分离石英与钠长石,研究了浮选条件对分离效果的影响以及捕收剂在矿物表面的吸附行为.结果表明,最佳浮选条件是浮选液的pH=2,阴、阳离子捕收剂的浓度分别为3.0×10-6 mol/L和4.0×10-6 mol/L;阴阳离子捕收剂在石英与钠长石两种矿物上表现出相同的吸附行为.在最佳浮选条件下,对不同配比的石英和钠长石混合物进行浮选,石英回收率为14%,钠长石回收率达80%,分离效果显著;对含微量长石的石英矿粉进行浮选,分离效果与石英与钠长石混合物相近.     

广东陆丰黄铁矿矿床原生矿石伴生金的综合利用及其评价

陆丰黄铁矿床的原生矿石中普遍含金，含量０．３ｇ／ｔ以上者产于－１００ｍ标高以上。金在矿石中的赋存状态以次显微金为主。利用浮选－氰化浸出工艺回收这些伴生金是可行的。应特别重视浅部矿石的综合利用     

Interaction of calcium dioleate collector colloids with calcite and fluorite surfaces as revealed by AFM force measurements and molecular dynamics simulation

Spherical calcium dioleate particles (∼ 10 μm in diameter) were used as AFM (atomic force microscope) probes to measure interaction forces of the collector colloid with calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate sphere and the fluorite surface is strong and has a longer range than the DLVO (Derjaguin–Landau–Verwey–Overbeek) prediction. The repulsive AFM force between the calcium dioleate sphere and the fluorite surface does not agree with the DLVO prediction. Consideration of non-DLVO forces, including the attractive hydrophobic force, was necessary to explain the experimental results. The non-DLVO interactions considered were justified by the different interfacial water structures at fluorite– and calcite–water interfaces as revealed by the numerical computation experiments using molecular dynamics simulation. The density of interfacial water at the fluorite surface is low and the fluorite surface is not strongly wetted by water molecules. In contrast to the water at the fluorite surface, water molecules at the calcite surface form tightly packed monolayer structures and the calcite surface is extensively hydrated by water molecules. The interfacial water structure agrees with the AFM force measurements and the flotation recovery data. The strong attraction between the calcium dioleate colloid and the fluorite surface, and the moderately wetted fluorite surface by water molecules explain the better flotation response of fluorite with the oleate collector colloid.     

四川盐源混合铜矿的工艺矿物学研究

利用扫描电镜、X射线能谱分析、XRD、MLA矿物检测软件对四川盐源混合铜矿的物质组成、赋存状态、嵌布特性、粒度特征、解离特征进行了研究.结果表明,该矿石中的主要有价金属是铜,含量为1.05％,主要赋存于黄铜矿、斑铜矿、辉铜矿、孔雀石中,脉石矿物主要有石英和长石,其次为方解石、绿泥石;主要矿物的粒度均小于20 μm,其中...