矿物浮选吸附平衡模型构建与应用：精准解析矿物表面离子/药剂特征吸附

矿物浮选吸附平衡模型是准确描述矿物浮选过程中所涉及的矿物表面离子/药剂吸附平衡的数学模型，首次实现了矿物表面位点与浮选药剂吸附作用亲和性的量化解析。传统浮选理论对矿物表面作用位点缺乏科学描述，难以阐明浮选药剂的吸附作用能力及平衡状态，新浮选药剂体系开发多以“试错法”“复配法”等经验性方法为主。药剂选择性吸附作为浮选作业的核心机制，若不能准确预测其在各矿物表面的吸附行为，将严重限制浮选工艺智能化控制的发展。本文详细论述了矿物浮选吸附平衡模型的构建原理，以赤铁矿-石英和一水硬铝石-高岭石两个浮选体系为例，通过对少量实验数据的拟合计算，解析出矿物表面活性位点密度Ns、加/去质子反应常数Kt1/Kt2、药剂吸附常数Kf等矿物浮选特征常数。将解析的矿物浮选特征常数代入到平衡模型中，预测出各条件下矿物表面电性、离子及浮选药剂的吸附量，通过零电点、实验及测试等方法验证了可靠性，形成了矿物浮选过程预测系统的内核算法。该算法对各条件下每种矿物药剂吸附的初步准确预测，可在一定程度上反映其可浮性趋势，有助于缩短浮选工艺开发周期，对矿物表面药剂吸附机理研究、浮选药剂分子设计、浮选工艺流程优化及智能控制等具有重...     

生物炭中溶解性炭黑的释放及环境效应

生物炭是一种价廉高效的吸附剂,可以通过农业废弃物或者其他固体生物质在低温下热解制得。由于生物炭具有多孔结构、较大的比表面积和阳离子交换容量、丰富的活性官能团等性质,可以吸附多种污染物,在固定重金属以及土壤中的碳循环、碳固定、土壤改良中起到了重要作用。生物炭的组分较为复杂,包括溶解性有机质、溶解性炭黑(Dissolved black carbon,DBC)、无机矿物等。其中,DBC在生物炭中的含量较高,且其含有羧基、酚羟基等多种官能团,可以和污染物发生强相互作用,但DBC的性质对污染物的吸附、迁移转化等行为产生的影响尚有待深入研究。此外,DBC作为一种相对独立的胶体颗粒,除含有大量的含氧官能团外,还具有高度芳香化、脂肪化的结构。因此,DBC进入土壤后可以与无机矿物颗粒发生相互作用,形成的有机-无机复合体能使其在土壤中稳定下来,也可能对土壤团聚体的形成有重要促进作用,但目前这些过程还未引起研究者的关注。与常规溶解性有机质相比,DBC较高的稠环度特征对无机矿物吸附特征可能会产生较大影响。因此,本综述探索了DBC的性质、无机矿物种类和性质对DBC与无机矿物颗粒之间相互作用的影响,以及DBC在无机矿物上吸附后对土壤特性的调控。DBC作为生物炭中具有高度芳香化结构的组分,在环境中的含量可能影响污染物的吸附、迁移等环境行为。DBC所含的极性官能团-OH、-COOH易与污染物发生相互作用。而由于不同类型污染物的化学性质存在较大差异,需充分理解DBC与污染物的相互作用机理,才能准确描述污染物和DBC的环境行为及风险。因此,系统理解DBC与污染物的相互作用及其对污染物迁移行为的影响有助于更好地预测土壤中污染物的环境行为和评估生物炭用于固定污染物的潜在应用。生物炭上有很多表面官能团,如羟基、醌、氢醌、羰基和羧基等,这些活性基团使其在氧化还原反应中成为重要的电子来源,从而影响其在土壤中的生物化学循环过程。DBC作为生物炭的重要组分,含有的羟基、羧基、羰基等官能团使其具有氧化还原活性、光反应活性等,因此研究DBC的反应活性对理解其物理化学性质及其与污染物的相互作用有重要意义。本文归纳了生物炭中DBC的性质、DBC与无机矿物的相互作用、DBC在无机矿物上吸附后对土壤特性的影响,并总结了DBC与污染物的相互作用、DBC的反应活性对其性质的影响等内容,以期为生物炭在土壤中的大规模应用奠定理论基础。     

水化膜对石英表面硫化作用的DFT研究

在许多地质检测和工业生产的过程中,硫化是一种常用的改善氧化矿浮选的预处理工艺。并不是所有的氧化矿物都可以硫化,因此石英表面的硫化十分重要。然而,该过程的详细机理目前仍不清楚,尤其是在存在水化膜的情况下。因此,本文使用密度泛函理论（DFT）来研究水化膜对石英表面硫化作用的影响。计算结果表明,水化膜对石英能否硫化起决定性作用,石英中的Si-O键比Si-S键强烈,导致石英表面水化膜对硫化氢（HS）有强大障碍,石英的硫化难以进行。为找出其内部机理,本文进一步分析了重叠布居、投影态密度（PDOS）和电子构型,并建立了它们与硫化行为的关系,研究其对硫化产物的性质和稳定性有何影响。     

矿物湿法超细磨矿中助磨剂的作用效应及其程度的研究

通过考察硬脂酸钠对重质碳酸钙－水矿浆粘度的影响和因硬脂酸钠在重钙表面吸附而导致的颗粒表面自由能的变化以及由此产生的对湿式搅拌磨细磨重质碳酸钙磨矿效果的影响,研究了助磨剂的各种作用效应及其程度。结果表明,助磨剂对矿物湿法细磨的助磨作用是改善矿浆流变性和吸附降低颗粒表面自由能两种效应综合的结果,其中前一作用较强。     

超声粒度仪及其应用

引言 超声粒度仪在有色金属矿湿式磨矿作业中,用来测量矿浆粒度分布(简称粒度)和固体重量百分比(简称浓度)。它是保证磨矿产品质量和实现磨矿系统自动控制的关键仪表。对磨矿生产过程进行控制时,矿石的粒度是重要依据。人工筛分析是确定矿浆粒度分布,常用的一种基本方法。这种分析方法不能在线连续测量粒度和浓度,没有实时控制和及时指导生产的意义。在粒度仪出现之前,人们曾用矿浆的浓度做为粒度分布的指示,是不可靠的,因为浓度和粒度之间没有固定关系。 磨矿的生产实践证明,矿粒磨得粗.磨机的矿石处理量就增加,但影响浮选的效益,造成金属…     

不同粒径金属基纳米颗粒的性质与其环境行为和生物效应的关系

随着纳米技术的高速发展,金属基纳米颗粒(MNPs)物理化学性质的变化与其环境行为、生物效应之间的关系受到广泛关注.由于独特的物理化学性质,MNPs被应用于农业、化工、航天等各个领域,其不可避免地释放到环境中,对环境生物及人类健康造成威胁.随着粒径的减小,MNPs展现出较大的比表面积、较高的表面电荷密度和表面能等独特的属性,这些性质在很大程度上影响着MNPs的界面反应及生物效应.本文综述了不同粒径MNPs的比表面积、表面官能团、表面能及表面电荷密度变化与其吸附、聚集、溶解等环境行为的关系,深入剖析了不同粒径的MNPs在不同环境条件(如溶解性有机质(DOM)、光照、pH值、离子强度)下的生物效应及个中机理,就现有研究中存在的问题提出了改进意见与建议.     

在选矿生产中清除杂物的改进实践

河北省矾山磷矿选矿生产流程包括破碎、磨矿、浮选、磁选、脱水以及过滤等工段。由于矿石开采过程中的导爆管等杂物混入矿石内,杂物随矿石进入选矿生产系统,堵塞渣浆泵矿浆入口、磁选机给料口、旋流器出口、回收水管出口和浓密机溢流口等,造成矾山磷矿生产系统流程不畅。因此该文通过试验研究,结合现场实际情况,在选矿生产系统的磨矿分级工段后安装高频直线振动筛,筛出矿浆中的导爆管等杂物,较好地解决了因导爆管堵塞各个生产环节而影响生产的问题。同时采用物料输送机将过滤出的导爆管等杂物输送到车间外部集中处理,确保了生产的稳定运行,效果非常明显,年可提高处理矿量20万t,提高尾矿柱塞泵、回水泵的运行效率10%～15%。     

云南某金矿浮选工艺研究

根据矿石性质和金的赋存状态,研究了磨矿细度、浮选药剂制度等选别条件对金回收的影响。结果表明:通过阶段磨矿-阶段浮选工艺流程后,最终可以获得产率为8.10%,金品位为32.20g/t,尾矿中金品位为0.34g/t,金的回收率为89.32%的金精矿。     

云南某金矿浮选工艺研究

根据矿石性质和金的赋存状态,研究了磨矿细度、浮选药剂制度等选别条件对金回收的影响。结果表明:通过阶段磨矿-阶段浮选工艺流程后,最终可以获得产率为8.10%,金品位为32.20g/t,尾矿中金品位为0.34g/t,金的回收率为89.32%的金精矿。     

矿物基摩擦材料的研究进展

摩擦材料是一种采用有机体/无机物压制而成的复合材料,广泛应用于运动车辆与工程机械中,发挥制动和传动功能,是工作中的核心部件。摩擦材料在汽车工业中应用最广,其性能优劣对汽车的安全性、稳定性具有十分重要的影响。矿物材料具有无毒、耐热性及化学稳定性好、无污染等优异的物理化学性质,且部分材料具有天然的纤维状、层状等特殊形貌结构,对摩擦材料的性能具有显著影响,是当前摩擦科学和工程领域关注的重点对象。然而,矿物材料的种类众多,成分和结构大相径庭,物化性能各有差异,导致矿物材料在摩擦材料中发挥作用的方式和机理也不尽相同。基于此,本文从矿物增强摩擦材料、矿物基摩擦材料的性能调控两方面,对矿物材料的成分、结构和物理化学性质及其对摩擦材料制品性能和使用效能的影响进行了综述。进一步从纤维状矿物增强调控、颗粒状矿物增摩调控和层状矿物减摩调控三个方面重点阐述了矿物调控摩擦材料的机理。开发新型矿物材料,加快表面改性及有效除杂等新技术的研发,加强矿物材料在摩擦材料中的作用机理研究,可以作为未来矿物基摩擦材料进行工业应用和理论研究的发展方向。     

Surface modification of basic copper carbonate by mechanochemical processing with sulfur and ammonium sulfate

Mechanochemical phenomena including mechanical activation and direct reaction have been widely observed particularly from dry grinding operation and various applications of the phenomena have been reported in many fields of chemistry. A new approach was introduced here to trigger partial reaction by co-grinding samples with small addition of water/liquid to achieve the purpose of surface modification with new phase formed. As one example, basic copper carbonate was wet ground with elemental sulfur and appropriate additives such as ammonium sulfate to transform the surface chemical composition from oxide to sulfide. Physicochemical characterizations of the prepared samples were conducted by a set of analytical methods, including X-ray diffraction analysis, Fourier Transform infrared spectroscopy, Raman spectroscopic analysis, SEM morphology analysis, Zeta potential and the dissolved copper concentration measurement. The beneficiation efficiency of the modified copper carbonate by a conventional froth flotation used usually for sulfide minerals was examined as a quantitative evaluation to optimize the experimental conditions for the modification operation. A metal yield over 80% was obtained easily after one step concentrating of the flotation operation, indicating that mechanochemically surface controlling concept may serve as a novel pathway to enrich and recycle carbonate-style nonferrous resources by applying the traditional mineral processing technology on the modified samples.     

Estimating the electrochemical reactivity of pyrite ores-their impact on pulp chemistry and chalcopyrite flotation behaviour

Prudent control of ore pulp chemistry via parameters such as redox potential (Eh), dissolved oxygen (DO) and pH, can markedly improve the flotation recovery, grade and selectivity of sulphide minerals. In this paper, the electrochemical reactivities of two pyrite minerals and their impact on chalcopyrite flotation are investigated using oxygen demand test and froth flotation. Changes in the surface chemistry/speciation are also investigated using X-ray photoelectron spectroscopy (XPS) and EDTA extraction technique. The oxygen demand test shows that the different pyrite ores display significantly different electrochemical reactivity. Furthermore, continuous aeration of the pulp reduces the reactivity of the pyrite ores. Solution and surface analysis results suggest the formation of hydroxide surface coatings on the pyrite surface as aeration progresses, preventing or minimising further oxidative reactions from taking place in the pulp. Flotation results showed that the flotation response of chalcopyrite is influenced by the pulp DO/Eh, and therefore the type and reactivity of the pyrite associated with it.     

New insights into the effects of particle size on the surface modification by low-temperature plasma from a perspective of surface oxidation degree

Particle size is an important parameter to determine the surface modification degree of sulfide minerals by plasma as well as the floatability of minerals. However, little studies have been reported to quantitatively relate surface oxidation and sample particle size to flotation performance. In this study, X-ray photoelectron spectroscopy (XPS) was used to characterize the surface species of arsenopyrite and pyrite at different plasma modification times. The critical oxidation degree was quantified as the proportion of hydrophilic oxidation species to hydrophobic species and correlated with flotation recovery. The results showed that the flotation recoveries of minerals with different particle sizes were determined by surface oxidation rate and critical oxidation degree. Fine particles were more likely to become hydrophilic under low-temperature plasma modification and yet the critical oxidation degree was also higher. The coarse particles being plasma modification presented a poor flotation recovery due to its low adsorption density of collector, although its oxidation degree was lower than the fine size fraction. The critical oxidation degree of pyrite was expected to be less than arsenopyrite, but its flotation recovery was higher under the same plasma medication time because of its slower oxidation rate.     

Application of three xanthates collectors on the recovery of nickel and pentlandite in a low-grade nickel sulfide ore using optimum flotation parameters

One of the challenges encountered when processing nickel ore is the presence of other minerals like chalcopyrite, pyrrhotite, pyrite and amphiboles in mineral dressing. Hence, there is need to investigate the selectivity of some collectors at optimum flotation parameters (particle size, milling time, pH and flotation cell) to maximize nickel and pendlandite recovery. Three xanthate collectors, namely potassium amyl xanthate (PAX), sodium isobutyl xanthate (SIBX) and sodium ethyl xanthate (SEX), were investigated in this study. In order to achieve this aim, the physical treatment of nickel sulfide ore and percentage chemical composition of nickel sulfide ore were investigated. The analyses of the concentrates were done using x-ray diffraction (XRD) and x-ray fluorescence spectroscopy (XRF). The optimum nickel and pentlandite recovery was achieved at particle size of 64.73 µm milled for 1.5 h, pH of 9.65 and using a new flotation cell. Also, SEX collector recovered more nickel and pentlandite contents compared to PAX and SIBX collectors when optimum parameters of particle size, milling time, pH and flotation cell were considered. In conclusion, the results showed that the selectivity of SEX is the strongest and will recover more pentlandite in a complex and low-grade nickel sulfide ore.     

Activation mechanisms of apatite by purifying reagent polyacrylamide for backwater from mineral processing in flotation of rare earths

This study revealed activation mechanisms of apatite by polyacrylamide (PAM) during flotation of rare earth minerals in Bayan Obo Ore. This activation leads to high phosphorus content in rare earth concentrate. Ultraviolet (UV) absorption measurements show that adsorption of PAM on the surfaces of apatite and rare earths follows a pseudo-second-order reaction kinetic model. The isothermal adsorption process follows the Freundlich adsorption model, indicating that the adsorption of PAM on apatite is a multi-layer, non-uniform process, that is, physical and chemical adsorption occurs simultaneously. The measured zeta potential shows that under weakly alkaline conditions, amide groups with a negative charge are adsorbed on the surface of apatite, increasing the electronegativity, so that the potential is shifted negatively; however, the negative shift of the potential on the surface of rare earths is insignificant. Fourier transform infrared (FT-IR) test and X-ray photoelectron spectroscopy (XPS) results imply that PAM is chemically adsorbed on the surface of apatite, while 506E undergoes stronger chemical adsorption than PAM on the surface of rare earth minerals. It is found that multi-layer, non-uniform adsorption of PAM combining physical and chemical adsorption occurs on the surface of apatite and the process is dominated by physical adsorption: the adsorption of PAM on surfaces of apatite is stronger than that on the surface of rare earth minerals. Such adsorption activates the apatite, causing it to float during the flotation of rare earths, which is the reason for the high phosphorus content in the rare earth concentrate.     

The effect of selective adsorption of dissolved aegirite species on the separation of specularite and aegirite

The separation of specularite from aegirite is challenging due to the similar floatability. Surface dissolution of minerals often occurs and affects their physicochemical properties. In order to investigate the effect of dissolved aegirite species on the separation of specularite and aegirite, the separation performance of these two minerals was explored through surface pretreatment before froth flotation. The adsorption mechanism was investigated via Zeta potential measurements, scanning electron microscope (SEM) tests, and X-ray photoelectron spectroscopy (XPS) analyses. Single mineral flotation experiments indicated that acidified pretreatment significantly reduced the floatability of aegirite (from 78.4% to 15.1%) and specularite (from 88.7% to 38.4%) at pH 10 with 6 × 10^-5 mol/L dodecylamine. The alkalified pretreatment only affected the flotation of aegirite (from 78.4% to 16.3%) at pH 10, while specularite maintained its floatability (85.4%). Mixed mineral flotation results confirmed that specularite was depressed while aegirite recovered its floatability with alkalified pretreatment. Zeta potential measurements and SEM analyses indicated that surface element dissolution occurred on the pretreated mineral surface, which increased the positive electrical property of minerals and weakened the adsorption of the dodecylamine. XPS results further revealed that the Si and Fe dissolved from the alkalified aegirite surface formed SiO₃^2-, Fe(OH)₃, and FeOOH at the specularite surface, which depressed the flotation of specularite.     

The depression behavior and mechanism of tragacanth gum on chalcopyrite during Cu-Mo flotation separation

In this work, tragacanth gum (TG), a nontoxic and environmental friendly organic polymer, was used to replace the traditional inorganic depressants of chalcopyrite during the flotation separation of copper-molybdenum sulfides. The single mineral flotation and artificial mixed minerals flotation experiments were conducted to investigate the effect of TG on flotation separation behaviour of molybdenite and chalcopyrite. The TG’s adsorption mechanism on molybdenite and chalcopyrite was investigated by X-ray photoelectron spectroscopy (XPS) and Time-of-flight secondary ion mass spectrometry (ToF-SIMS). The flotation experiment results showed that at pH 3–8, TG had a significant selective depressive effect on chalcopyrite flotation and it was enhanced with increasing TG concentration, but hardly affected the molybdenite flotation. XPS analysis showed that TG was chemically adsorbed on both molybdenite and chalcopyrite surfaces and ToF-SIMS results demonstrated that the interaction of TG and chalcopyrite was stronger than that of TG and molybdenite. Further, XPS narrow scanning analysis suggested that TG might chemisorb onto chalcopyrite via chemical bond between the carboxyl groups and Fe sites on bulk chalcopyrite surface as well as the hydrogen bond between the hydroxyl groups and surface Fe oxides/hydroxides. The strong TG adsorption on chalcopyrite hindered the subsequent adsorption of PBX on chalcopyrite surface, thus chalcopyrite was significantly depressed and Cu-Mo flotation separation was achieved.     

Effects of fine–coarse particles interaction on flotation separation and interaction energy calculation

The particle interaction behavior is important in flotation process, and the interaction energy calculation is helpful for evaluating this behavior. This study investigates and compares the floatability of magnesite, dolomite, and quartz in single mineral flotation and artificial mixture flotation with dodecylamine (DDA) as collector. The results showed that while the pH, dissolved ions, and competitive adsorption had a minor influence on their floatability, fine magnesite and dolomite largely decreased the recovery of quartz. Scanning electron microscope (SEM) analysis on the flotation products demonstrated severe masking of fine particles on the surface of quartz. The extended-DLVO (Derjaguin–Landau–Verwey–Overbeek) theory was applied to calculate the interaction energy between the mineral particles, and the results showed that the interaction force between magnesite and quartz and between dolomite and quartz was attractive; therefore, fine magnesite and dolomite particles were easily masked on the surface of quartz. The calculation results agree with the experiment results and explain the mechanism of particles’ interaction and the reasons for the differences in single mineral flotation and artificially mixed minerals flotation.     

Effects of type and dosages of organic depressants on pyrite floatability in microflotation system

Pyrite is considered as a disturbing sulfide mineral in the beneficiation of sulfide minerals and coal and in order to prevent floating of pyrite in the flotation, different inorganic, organic and biological depressants could be used. The most important organic pyrite depressants are starch, dextrin, guargum, carboxymethyl cellulose (CMC), ethylene diamine tetra acetic acid (EDTA), Diethylenetriamine (DETA). In this paper, flotation experiments were carried out by modified Halimond tube. At first, flotation experiments were performed to obtain optimal pyrite flotation condition (suitable collector and frother for maximum recovery). In optimal condition (collector: KAX?+?KIPX , 16?ppm; collector condition time: 4?min; frother: Poly Propylene Glycol (A65), 20?ppm; frother condition time: 30?s), pyrite recovery increased to 95.63%. Flotation kinetics experiments were performed and various kinetic models were evaluated on pyrite flotation. The results showed that flotation kinetics of pyrite is second-order. After obtaining optimal condition for flotation and kinetic studies, the effects of type and dosage of different organic depressants including starch, dextrin, guargum, carboxymethyl cellulose, EDTA and DETA at three concentrations (50, 100, 150?ppm) at neutral pH were comprehensively investigated. The results of the experiments showed that DETA can significantly reduce the recovery of pyrite at 150?ppm by 44%.     

S135钻杆断裂原因分析

通过化学成分分析、力学性能测试、显微组织分析等手段对某断裂失效的S135钻杆进行了材质理化检验;采用SEM和EDS分别对断口形貌及表面腐蚀产物成分进行了分析。结果表明：该钻杆的材料性能符合APISpecSD规范要求,钻杆断裂的主要原因是硫化氢应力腐蚀开裂,并伴有一定程度的二氧化碳腐蚀。