Bioleaching of complex polymetallic sulfide ores by mixed culture

Bacterial leaching of single sulfide minerals and polymetallic sulfide ores was operated in shake flasks and small-scaled columns.The results show that bioleaching of jamesonite is not accessible,the iron extraction rate of pyrrhotite bioleaching reaches 98.2% after 26 d,and the zinc extraction rate of marmatite bioleaching reaches 92.3%,while the corresponding iron extraction reaches only 13.6% after 29 d.Pulp density has a significant effect on metal extraction of pyrrhotite and marmatite bioleaching.The corresponding metal extraction rate decreases with the increase of pulp density.For the polymetallic sulfide ores,zinc extraction of 97.1% is achieved after bioleaching in shake flasks for 10 d,while only 7.8% is obtained after bioleaching in small-scaled column.Analytical results of scanning electron microscopy（SEM） and energy dispersive X-ray analysis（EDX） reveal that large amount of calcium sulfate is formed on the mineral surface.     

Electrochemical oxidation of pyrrhotute in aqueous solution

The anodic surface oxidation of natural pyrrhotite in 0.3 mol/L KCI and HCI solution （pH 4.0） and 0.1 mol/L Na2B4O7 solution （pH 9.18） respectively was investigated by using cyclic voltammetry, Tafel plot, and chronoamperometry. In 0.3 mol/L KCl and HCl solution （pH 4.0）, at potential less than 0.5 V（vs SHE）, the production of anodic oxidation on pyrrhotite surface can not maintain a stable phase to form a passive film. In 0.1 mol/L Na2B4O7 solution （pH 9.18）, when the electrode potential increases to more than 0.5 V （vs SHE）, part of S is oxidized to sulfate, making the passive film somewhat porous, but elemental S and metal oxidates Fe（OH）3 still remain on the electrode surface, and the passive film can not be broken down totally. According to PARCalc Tafel analysis, the corresponding corrosion current density （J0） is 5.34 μA/cm^2 , which is also the exchange current density of the oxidation reaction on pyrrhotite electrode surface in 0. 1 mol/L Na2B4O7 solution （pH 9. 18）. The electrochemical dynamics equation of the oxidation was determined.     

Self-diffusion of iron and sulfur in ferrous sulfide

By use of radiotracer techniques, the iron self-diffusion coefficient in ferrous sulfide single crystals above 620 K was found to be D = D ₀ exp {–[(81±4) + (84±20)]/RT}where the exponential units are kJ/mole, D ₀ is 1.7± 0.1×10^–2 and 3.0±0.2 × 10^–2 cm² sec^–1 for diffusion in the a- and c-directions, respectively, and is the deviation from stoichiometry as given in the formula, Fe _1-S.This is a vacancy diffusion mechanism and is discussed in detail. Below 570 K the coefficient is lower than the values given by this equation because of vacancy ordering. The diffusion coefficient for sulfur is many orders of magnitude smaller than for iron. The significance of the data for the Fe–S ₂ reaction and other examples of iron diffusion is discussed.     

云南某含银铜矿伴生银矿物强化回收实验研究

云南某含银铜矿石银品位为21.77 g/t,主要赋存于黄铜矿、游离银和磁黄铁矿中,在选别过程中铜硫分离时兼顾银的回收具有一定的难度。采用抑硫浮铜流程,研究筛选出石灰及Z200作为合适的调整剂和高效捕收剂,在抑制黄铁矿、磁黄铁矿的同时强化银的回收。最终闭路试验获得了品位23.92%、回收率97.10%的铜精矿,且含银136.38 g/t,银的回收率达到77.05%,实现了铜硫分离的同时强化银的回收。     

山东某含金磁黄铁矿浮选尾矿磁选回收试验研究

山东某含金磁黄铁矿原矿金品位1.60 g/t,硫品位1.86%,属含金硫铁矿。矿石性质研究结果表明,部分以磁黄铁矿为载体的金,矿物含量为0.96%,金品位8.25 g/t,原矿金分配率5.25%。生产流程对以磁黄铁矿为载体的金矿物的回收水平仍有提高空间。为了解决这一问题,开展了从生产原矿和生产尾矿中回收以磁黄铁矿为载体的金的对比试验,结果表明,磁选不宜用于原矿、重选不宜用于尾矿中载金磁黄铁矿的回收;尾矿磁选流程可以实现含金磁黄铁矿的有效富集,最终选择全粒级磁选工艺流程,获得了金品位1.52 g/t,硫品位2.87%的含金磁黄铁矿。尾矿金、硫回收率分别为52.09%、62.93%,对原矿回收率分别为12.27%、18.56%,实现了以磁黄铁矿为载体的金矿物的综合利用。     

西藏某钼硫矿等可浮选矿工艺研究

针对西藏某钼硫多金属矿石进行选矿工艺试验研究。在方案试验及条件试验的基础上,推荐采用钼硫等可浮选-再磨分离工艺流程,钼硫分离采用有效的脉石抑制剂六偏磷酸钠和铜、硫组合抑制剂YLN与QY,闭路试验可获得精矿Mo品位50.69%、Mo回收率83.39%的良好试验指标。     

新型有机抑制剂RC对黄铁矿和磁黄铁矿的抑制作用研究

研究了有机抑制剂RC对黄铁矿、磁黄铁矿的抑制作用。实验结果表明，RC对黄铁矿和磁黄铁矿均有较强的抑制作用。红外吸收光谱证明：RC分子结构中含有—COO^-、—SO3^-、—OH等多种官能团，黄药与RC之间存在一种竞争吸附的关系，在pH为10的环境中，吸附对RC有利，由于RC携带众多的亲水集团，使得矿物表面更易亲水，进而抑制矿物。     

云南某含磁黄铁矿铜矿石浮选新工艺研究

针对矿石中磁黄铁矿干扰铜浮选、铜矿物嵌布粒度细等问题,采用铜硫混浮-粗精矿再磨工艺处理该矿石,以石灰和亚硫酸钠作为磁黄铁矿的抑制剂,同时采用选择性较高的DY-1为铜矿物捕收剂。闭路试验获得了铜品位为24.49%、含银335.37g/t,铜回收率为89.15%、银回收率为65.33%的铜精矿。     

某难选铜铁矿选矿试验研究

某含硫铜铁矿磁黄铁矿含量较高,使用常规抑制剂石灰抑制硫,铁精矿中硫含量超标。原矿中铜品位0.35%,铁品位28.95%,硫品位9.84%,铜大部分以黄铜矿形式存在,还含有少量的墨铜矿,铁主要以磁铁矿形式存在。使用新型抑制剂WDF-3作抑制剂,不仅能较好的抑制硫,而且后续铁精矿降硫时,较易被活化脱除。采用先浮选铜→浮选尾矿磁选→磁选粗精矿再磨再选→铁精矿浮选硫,中矿依次返回的闭路试验流程,获得铜精矿中Cu品位19.58%,回收率为74.05%,硫精矿中S品位50.21%,回收率81.59%,铁精矿中Fe品位64.89%,回收率53.87%,获得较好的选别指标。     

Physical characterization and pressure—temperature microscopy of the pyrite—pyrrhotite transformation

Structural changes occurring during the hydrogen-assisted pyrite-pyrrhotite transition are characterized over the temperature range 400–600 °C. Newly developed pressure-temperature microscopy gave in-situ observations of pyrite decomposition at elevated temperatures and gas pressures. Composition of pyrrhotites was measured by X-ray diffraction and correlated with krypton surface areas. Surface areas increased with an increase in pyrite reduction due to a decrease in molar volume accompanied by the development of porosity. Increases in specific surface area are inversely proportional to the reduction temperature. Heats of adsorption of krypton on pyrite increase linearly with increases in the relative amount of the (100) crystallographic faces.