Chemical and mineralogical composition of ilmenite: Effects on physical and surface properties

Some physical and chemical properties of three ilmenite samples: IL-F (purchased from the mineral dealership of A and F Krantz), IL-Q (Qara-aghaj deposit, Iran) and IL-K (Kahnuj deposit, Iran) were studied. The substitution of different amounts of Mg, Mn and V in the crystal structure of ilmenite was identified by microprobe analysis. Different amounts of hemoilmenite exsolution were observed inside all three ilmenite samples using SEM, electron microprobe and X-ray diffraction analysis. Using these analytical techniques, titanite phase was found inside the IL-K ilmenite. The XPS analysis indicated that the contents of Fe³⁺ are 5.66, 5.33 and 3.72% for IL-F, IL-Q and IL-K, respectively which are in good agreement with the amounts of hemoilmenite exsolution. Mg and V contents in the ilmenite crystal structure have a good negative correlation with lattice constants (LC), unit cell volume, crystallinity index, specific gravity and IEP, while the Mn content correlates positively with these parameters. The IEP determined as 4.2, 5.4 and 6.25 for IL-F, IL-Q and IL-K, respectively, has a negative correlation with Fe³⁺ ions and ilmenite floatability. In comparison with magnetic susceptibility, the electrical resistivity of ilmenite has a higher correlation with surface properties (IEP and floatability), lattice constants, and unit cell volume.     

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.     

钛铁矿浮选药剂及微波预处理改善其浮选指标的研究进展

我国钛资源钛品位低、性质复杂,浮选是富集钛铁矿最有效的方法。从捕收剂、活化剂、抑制剂角度综述了钛铁矿浮选药剂的研究进展。综述了钛铁矿表面性质与其可浮性的关系及微波表面预处理提高钛铁矿可浮性的研究进展。钛铁矿浮选时捕收剂主要通过化学吸附方式作用在矿物表面,捕收剂组合使用较单一捕收剂对钛铁矿的浮选指标好;在钛铁矿浮选抑制剂方面,铅离子活化的报道较多,铜离子活化、硫酸活化等也逐渐被报道;微波用于钛铁矿表面预处理,降低了捕收剂、抑制剂、活化剂等浮选药剂的消耗量,具有较好的运用前景。今后,钛铁矿浮选技术发展的主要方向仍然是开发新型、环保、低成本、高效的浮选药剂。     

越南某钛铁砂矿选矿试验

越南某钛铁砂矿粒度为-80目占62.34%,TiO₂品位为6.04%,主要金属矿物为钛铁矿和钛磁铁矿,部分钛铁矿物已单体解离。为高效开发利用该矿石资源,对有代表性的矿石进行了选矿试验研究。结果表明：①矿石采用1粗1精摇床重选、重选中矿1次强磁选均可获得较高品位的钛铁精矿;②矿石经1粗1精摇床重选,重选中矿1次强磁选,重选尾矿和强磁选尾矿合并再磨至-200目占80%后经1粗2精、中矿顺序返回浮选流程处理,最终获得了TiO₂品位为46.45%、回收率为77.52%的钛铁精矿。     

Flotation behaviors of ilmenite,titanaugite, and forsterite using sodium oleate as the collector

The flotation behaviors of ilmenite, titanaugite, and forsterite using sodium oleate as the collector were investigated using microflotation experiments, zeta-potential measurements, Fourier transform infrared (FT-IR) analyses, X-ray photoelectron spectroscopy (XPS) analyses and the artificially mixed minerals flotation experiments. The results of the microflotation experiments indicate that ilmenite exhibits good floatability when pH > 4.0. Titanaugite possesses a certain floatability at pH 4.0–6.0 and pH > 10.0, and forsterite possesses certain floatability at pH 5.0–7.0 and pH > 9.0. The results of FT-IR and XPS analyses indicate that sodium oleate mainly interacts with Fe, resulting in ilmenite flotation; that the Ca and Mg on the titanaugite surface chemically reacted with sodium oleate, and that the Mg on the forsterite surface chemically reacted with sodium oleate under acidic condition. However, sodium oleate mainly reacted with the Ca and Mg on the titanaugite surface, whereas sodium oleate mainly reacted with the Mg on the ilmenite and forsterite surfaces under alkaline conditions. The results of the artificially mixed minerals flotation experiment demonstrate that the concentrate of TiO₂ grade increases from 16.92% to 30.19% at pH 5.4, which represents the appropriate conditions for the flotation separation of ilmenite from titanaugite and forsterite under weak acidic conditions.     

On the mechanism of the flotation of oxides and silicates

The mechanism of flotation of oxide and silicate minerals was established long ago as being due to the electrostatic attraction between the charged surface and the charge of the collector. What is less well established is the mechanism of the charging of the mineral surface. Most researchers have postulated that the adsorption of H⁺ is the cause. However, the adsorption model and its derivatives (such as the amphoteric and multisite-adsorption models), do not successfully describe the data for the zeta potential as a function of pH. In particular, these adsorption models have the following features that are not observed: (i) they are symmetrical about the point of zero charge, whereas the data is asymmetrical, (ii) they have an inflection at the pK_a values, leading to an asymptotic approach to the point of zero charge, whereas such an inflection is not observed, and (iii) they only fit the data in its extremes, that is, when the pK_a values differ by orders of magnitude, or are very close to one another. An alternative mechanism of charging is proposed here that is based on the dissolution of ions from and deposition of ions onto the mineral surface. It is shown that this model (a) fits the data, (b) is consistent with the thermodynamic model for reversible interfaces, (c) is consistent with the thermodynamics of the overall reaction and its solubility, (d) indicates reasons for the ageing of surfaces and (e) displays the observed features of zeta potential measurements as a function of pH, that is, it is pseudo-Nernstian and asymmetrical in nature. Application of the proposed theory is discussed for the flotation of quartz and corundum.     

钛铁矿资源加工研究现状

对钛铁矿的浮选药剂、浮选工艺,钛精矿冶金处理的研究现状进行了分析讨论,认为加强微细粒钛铁矿的浮选能提高钛资源的回收率,而钛精矿中钙、镁杂质的降低是高效利用钛资源的关键。     

The influence of particle shape properties and associated surface chemistry on the flotation kinetics of chalcopyrite

The role of particle shape properties in determining flotation kinetics was investigated in this study. −150/+75 μm chalcopyrite was floated in a microflotation cell, and shape properties of the timed concentrates were quantified using a mineral liberation analyser - a mineralogical characterisation system based on automated scanning electron microscopy. It was found that, when floated in the absence of collector, particles with angular shape features reported to the concentrate faster than round particles. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) showed that angular particles also exhibited surface chemistry characteristics favourable for flotation. When particle floatabilities were high (i.e. when floated in the presence of potassium amyl xanthate), shape properties were not found to contribute significantly to the rates at which particles floated.     

Effect of contact angle,surface tension and zeta potential on oil agglomeration of celestite

The influences of contact angle, surface tension and zeta potential on oil agglomeration recovery of celestite mineral have been investigated in the present work. Therefore, celestite mineral in methanol–water suspension was agglomerated by the use of oil (kerosene) in the presence of sodium oleate as a surfactant. The zeta potential values of celestite surfaces were measured depending on pH and sodium oleate concentration. The zeta potential values of celestite surfaces became negative even more owing to the sodium oleate adsorption. However, this phenomenon did not affect the oil agglomeration recovery at all. It was found that both increasing contact angle and surface tension raised the oil agglomeration recovery of celestite mineral. Eventually, the agglomeration degree of celestite mineral in the suspension was not lower than a particular surface tension value corresponding to the critical solution surface tension for oil agglomeration (γ_c-a). The γ_c-a values were slightly greater than the critical surface tension of wetting (γ_c) values.     

XT新型浮钛捕收剂的工业试验

通过药剂筛选选出A、B、C三种药剂,利用药剂之间的协同效应原理,在实验室找出最佳配比,合成了XT新型浮钛药剂,实验室和工业试验表明,该药剂捕收性能和选择性较好,是一种较为理想的新型浮钛捕收剂。     

蒙脱石分散体系中用Zeta电位修正静电作用能的计算

针对扩展DLVO理论的静电作用能计算中表面电位难以测定,讨论以Zeta电位代替表面电位进行静电作用能计算的可行性。计算了蒙脱石表面电位,运用扩展的DLVO理论分别用Zeta电位和表面电位计算蒙脱石悬浮液的临界硬度,并通过蒙脱石悬浮液的临界硬度试验进行验证。试验结果表明:(1)悬浮液中蒙脱石颗粒表面与滑动面之间的水和电解质离子起到屏蔽表面电位的作用,表面电位计算的静电势能并不能反映颗粒间的静电作用;用Zeta电位代替表面电位计算颗粒间静电作用能,与实验结果更相符;(2)颗粒间滑动层开始接触时,水化作用能开始增大,电解质离子不仅减小了颗粒间的静电斥力,还减小了滑动层厚度,使水化作用距离缩短,颗粒更容易接近从而发生凝聚;(3)随电解质浓度的增加,蒙脱石颗粒Zeta电位和表面电位的绝对值均表现为减小的趋势,且表面电位的变动幅度要远高于Zeta电位的变动;双电层与滑动层厚度均呈指数减小。     

NaOH和机械搅拌对锂辉石表面及浮选行为的影响

NaOH和机械搅拌在锂辉石浮选预处理过程中发挥着重要的作用,为了探明其作用机理,开展了锂辉石单矿物和实际矿石浮选试验,进行了X光电子能谱(XPS)和电感耦合等离子体光谱(ICP)检测分析。结果表明,经过3 000mg/L NaOH用量并施以相应时长和速度的搅拌预处理,可使-0.15+0.074mm粒级的锂辉石单矿物回收率提升70%左右;在相同的3 000mg/L NaOH用量下,静置浸泡和施加叶轮线速度3.93m/s的搅拌。检测分析结果表明,固液分离液中的Si离子浓度增大且矿物表面Al和Li原子相对含量均增大;说明锂辉石矿物表面发生了溶蚀现象,且机械搅拌可以促进其表面的溶蚀,暴露更多的金属阳离子为油酸根在锂辉石表面的吸附提供更多的吸附位点;但表面溶蚀后产生的硅酸盐阴离子组分具有较强的亲水性,吸附于矿物表面,致使单矿物可浮性提升而强化机械搅拌后实际矿石浮选试验中Li2O回收率下降。该研究对锂辉石及硅酸盐矿物浮选预处理的研究具有重要的意义。     

采用响应曲面法优化蓝晶石浮选试验

本文针对河北邢台卫鲁地区蓝晶石选矿流程中强磁选后的非磁性产品进行粗选试验研究。在单因素条件试验的基础上,根据Box-Behnken原理,建立了响应值精矿品位及精矿回收率与三个主要影响因素之间的回归方程,探索了最佳的药剂用量。在最佳浮选工艺条件下,即矿浆浓度25%,十二胺盐酸盐用量45 g/t,抑制剂淀粉用量380 g/t的条件下,预测精矿品位为39.46%,精矿回收率为66.53%。验证试验与预测值的相对误差均为0.02%,与模型预测值吻合度较高。证明了二者之间的高度相关性,说明该预测模型在本试验的研究范围内是有效、合理的。     

白钨矿常温浮选基础研究

以白钨矿、萤石和方解石单矿物为研究对象,通过单矿物可浮性试验、动电位测定、吸附量测定以及溶液化学分析,对白钨矿的常温浮选行为及机理进行了系统研究。浮选试验结果表明,用CaO+Na₂CO₃（以1∶3的质量比添加）调节矿浆pH=11.0、硅酸钠为抑制剂、733氧化石蜡皂为捕收剂,可以实现常温下白钨矿与萤石和方解石的有效分离。用CaO+Na₂CO₃调浆后,萤石和方解石表面的Ca²⁺浓度大于白钨矿表面的Ca²⁺浓度,加入硅酸钠后,萤石、方解石表面动电位显著负移,而白钨矿表面电位变化不明显。吸附量测定及溶液化学计算表明：硅酸钠在3种矿物表面的吸附量由大到小为萤石＞方解石＞白钨矿,即3种矿物表面生成硅酸钙的难易程度由强到弱依次为萤石>方解石>白钨矿。     

连云港某含氟磷灰石浮选提纯试验研究

连云港某含氟磷灰石矿P2O5含量为31.23%,脉石矿物主要为白云石、方解石和石英,含量分别为13.68%、6.82%和2.33%。为开发利用该矿石,采用正浮选工艺对其进行提纯试验研究。结果显示,在磨矿细度为-0.074 mm占76.80%条件下,以NaOH为pH调整剂,碳酸钠和硅酸钠为抑制剂兼分散剂,油酸钠为捕收剂,在浮选机叶轮转速为2 000 r/min,充气量为0.25 m³/h条件下,经1粗1精1扫闭路浮选,获得了P₂O₅含量为36.68%、回收率为89.90%的磷灰石精矿。红外光谱测定和表面Zeta电位测定结果表明,油酸钠主要以化学吸附形式吸附在磷灰石表面,降低了磷灰石的表面动电位,研究结果对类似磷矿资源的回收利用具有参考意义。     

攀钢选钛厂微细粒钛铁矿浮选工艺技术的优化

攀钢选钛厂攻克微细粒钛铁矿浮选工艺技术,提高了钛铁矿回收率,为攀钢选钛厂的产能提升创造了条件。介绍了选钛厂微细粒钛铁矿浮选的技术进步,论述了选钛扩能改造后微细粒钛铁矿浮选的工艺技术特点及发展方向。     

Preliminary results on selective surface magnetization and separation of alumina-/silica-bearing minerals

The efficient and economical separation of alumina/silica minerals is critical to alumina production. In this work, selective surface magnetization was adopted to separate alumina-/silica-bearing minerals. The zeta potentials of boehmite, quartz, and magnetite with and without 100 ppm sodium fluoride (NaF) were measured. Results show that NaF could extend the favorable pH range to 7.4–8.5 for the selective magnetic coating of boehmite. X-ray diffraction and scanning electron microscopy analyses indicate that synthesized magnetite particles are preferentially adsorbed onto boehmite in the artificial bauxite of boehmite and quartz, and then aggregate to form a dense magnetic layer during surface magnetization. The magnetic hysteresis loop determined by Vibrating Sample Magnetometer further confirms that the concentrate from magnetic separation contains magnetic substances and the concentrate is weakly magnetic. Based on the separation results for artificial bauxite, experiments were conducted on the selective surface magnetization of gibbsite–boehmite mixed bauxite and low-temperature Bayer red mud. The results demonstrate that alumina-/silica-bearing minerals could also be separated to a certain extent. Selective surface magnetization exhibits the potential to separate alumina/silica minerals for practical applications and thus deserves further study.     

海泡石表面电性研究

海泡石的表面电性对加工及开发应用有很大的影响 ,因此有必要对海泡石的表面电性进行研究。本文考察了纤维状及土状海泡石原料的 ζ电位 ,以及悬浮液酸度、分散剂种类、不同加工方法、阳离子活性剂用量等因素对ζ电位的影响 ,并探讨了其原因     

TOF-SIMS studies of surface chemistry of minerals subjected to flotation separation – A review

This paper reviews the applications of time of flight secondary ion mass spectrometry (TOF-SIMS) used for surface chemical analysis of mineral in the context of froth flotation. A wide range of applications are reviewed, including; interactions of reagents on the surface of mineral phases during flotation separation, determining the effects of various transferred ions from different minerals or the slurry, evaluation of hydrophobicity, identifying the relationship between mineral surface chemistry and contact angle, and evaluation of grinding effects. Conclusions indicated that TOF-SIMS, as a unique surface analysis technique, can potentially provide a direct determination of parameters which control the surface reactivity and consequently plays an important role in determining flotation behaviour of minerals.