An in situ ATR-FTIR study of mixed collectors BHA/DDA adsorption in ilmenite-titanaugite flotation system

This paper researched the enhanced flotation separation performance of ilmenite and titanaugite using the mixed collector benzhydroxamic acid/dodecylamine(BHA/DDA). The interface assembly mechanism was mainly investigated through in situ attenuated total reflectance Fourier transform infrared(ATRFTIR) spectroscopy combined with the two-dimensional correlation spectroscopy(2 D-COS) and X-ray photoelectron spectroscopy(XPS). It has been found that BHA/DDA mixed collectors successfully separate ilmenite from titanaugite at a molar ratio of 8:1. Zeta potential experiments suggested that, in the presence of mixed collector system, the BHA-DDA complex adsorbed on the ilmenite surface via the chemically adsorbed BHA and the electrostatically adsorbed DDA, however, the complex adsorbed on the surface of titanaugite unstably. According to in situ ATR-FTIR combined with 2 D-COS and XPS results,the interface assembly mechanism of BHA/DDA is summarized as: the function group of BHA molecules first binds to the metal sites on minerals to form bidentate ligand, then DDA co-adsorbed with BHA on the surface of minerals through hydrogen bonding. DDA may change the adsorption modes of some BHA on the ilmenite surface from four-membered ring to five-membered ring, while the modes on the titanaugite surface is true opposite. Finally, recommended adsorption configurations of the BHA/DDA complex on the two mineral surfaces are proposed.     

矿物粉体自溶液中的吸附 Ⅰ 黄铁矿吸附黄药机理的研究

本研究用天然黄铁矿制成的电极进行稳定电位,原电池放电和电位阶跃测量的实验。实验结果表明,在溶有氧的溶液里黄铁矿吸附黄酸根形成双黄原的反应可以表示为原电池作用,且反应的活化能与复盖度成线性关系。     

Adsorption behavior and mechanism of copper ions in the sulfidization flotation of malachite

Malachite is one of the main minerals used for the industrial enrichment and recovery of copper oxide resources, and copper ions are unavoidable metal ions in the flotation pulp. The microflotation, contact angle, and adsorption experiments indicated that pretreatment with an appropriate concentration of copper ions could improve the malachite recovery, and the addition of excess copper ions reduced the hydrophobicity of the malachite surface. The results of zeta potential tests indicated that sodium sulfide and butyl xanthate were also adsorbed on the surface of malachite pretreated with copper ions. X-ray photoelectron spectroscopy (XPS) results indicated that —Cu—O and —Cu—OH bonds were formed on the surface of the samples. After pretreatment with an appropriate concentration of copper ions, the number of —OH groups on the mineral surface decreased, whereas the number of Cu—S groups on the mineral surface increased, which was conducive to the sulfidization of malachite. After adding a high concentration of copper ions, the —OH groups on the mineral surface increased, whereas the number of Cu—S groups decreased, which had an adverse effect on the sulfidization flotation of malachite. Time-of-flight secondary ion mass spectrometry showed that pretreatment with copper ions resulted in a thicker sulfidization layer on the mineral surface.     

Effects of nanobubble and hydrodynamic parameters on coarse quartz flotation

Quartz, the second most abundant mineral in the earth's crust, is a gangue mineral in practically every flotation process. Coarse quartz flotation has been a long standing problem in various mineral processing plants to reduce milling cost and increase valuable mineral recovery. Based on this, the effects of nanobubbles(NBs) and hydrodynamic parameters on coarse quartz particle flotation were systematically investigated. Mechanical flotation experiments were carried out using the 7 cm and 9 cm diameter impellers in order to produce different hydrodynamic conditions. 900–1300 rpm impeller speeds were used for the 7 cm diameter impeller and 554–786 rpm for the 9 cm diameter impeller. The results show that the presence of NBs increased the flotation recovery of à425 + 106 lm quartz by up to 21%. For the7 cm diameter impeller, the maximum flotation recoveries of 86.4% and 98% were obtained in the absence and presence of NBs at Reynolds number(Re) of 81,000 and 66,000, respectively. For the 9 cm diameter impeller, the maximum recoveries of 86.3% and 97.5% were obtained in the absence and presence of NBs at Re of 90,000 and 75,000, respectively. NBs increased the flotation rate constant up to 36%.     

Effect of butanol on flotation separation of quartz from hematite with N-dodecyl ethylenediamine

In order to investigate the effect of butanol on quartz flotation when N-dodecyl ethylenediamine(ND)was used as collector, single mineral flotation and artificial mixed mineral(hematite and quartz were mixed at a mass ratio of 3:2) separation were conducted in the laboratory. Experimental results indicated that addition of butanol could improve the collecting performance of ND on quartz and enhance the floatability of quartz. Best flotation recovery of quartz was obtained when butanol was mixed with ND at a mass ratio of 1:1. Moreover, the molecular structure of alcohols had a significant effect on mineral recovery. Best separation efficiency could be obtained when tert-butanol was added as it had the largest cross-sectional area. Zeta potential measurements indicated that alcohols could strengthen electrostatic adsorption between quartz and collector. Molecular dynamic simulations revealed that co-adsorption of alcohols along with ND had taken place on the quartz surface, and ND/tert-butyl combinations were more easily absorbed on the quartz surface.     

阳离子表面活性剂CTAB吸附机理的研究

本文测定了阳离子表面活性剂 CTAB(溴化十六烷基三甲基铵)水溶液在石英和甲基化石英表面的接触角、(?)电位及吸附等温线。讨论了在酸性溶液(PH=4.5)和碱性溶液(PH=8.5)情况下 CTAB 的吸附机理。研究结果表明:甲基化和非甲基化表面吸附机理的差别;甲基化表面在水溶液中长时间浸泡其表面由憎水向亲水方向转移是在作表面性能研究时必须严重关注的问题。     

Hydrophobic-surface of copper from converter slag in the flotation system

The converter slag from a smeltery in Daye contains 2.01% copper. The floatability of copper has a significant influence on the flotation of converter slag. Flotation tests, contact angle tests and FTIR were conducted to assess the influences of pH and different flotation concentrators on its hydrophobic process, mechanism and flotation. The results show that since chemisorptions are formed on the surface, hydrophobicity of copper is highly enhanced by xanthate, butylamine dithiophosphate and Z-200. The hydrophobic-surface of copper becomes worse with low recovery in strong acid and alkali situation. When pH value is 10, butylamine dithiophosphate and butyl xanthate are used as the mixed-collector, the grade of copper is 40.01% and that of tailings is 0.37%.     

Insight into mineral flotation fundamentals through the DFT method

Flotation is a complex process that occurs in solid–liquid-gas multiphase systems, and its main factors include the minerals, separation medium, as well as various flotation reagents. The study of mineral properties and interactions with other components such as reagents and water lays the basic theoretical foundation for flotation. Density functional theory (DFT) calculations can qualitatively evaluate the exchange of matter and energy between the mineral system and the surroundings and quantitatively characterize these behaviors, which greatly expands the breadth and depth of flotation studies. This review systematically summarizes the advances of flotation research based on DFT studies, including the study of mineral crystal chemistry represented by the theory of lattice defects, mineral surface hydration such as hydrophilicity and hydrophobicity, surface regulation mechanism, and collecting mechanism based on surface adsorption theory. More significantly, it systematically elaborates different types of collectors according to their characteristics and emphatically explains the mechanism of some typical collectors in detail.     

Insights into the influence of temperature on the adsorption behavior of sodium oleate and its response to flotation of quartz

Temperature affects the flotation of quartz in the calcium/sodium oleate(NaOL)system,while there is a lack of understanding of its potential mechanism.Therefore...     

1,3-二氧戊环对锂的表面改性机理

为研究预处理液对二次金属锂电极的表面改性机理,采用1,3-二氧戊环作为预处理液,对锂电极进行浸泡处理,然后与LiCoO2组装成扣式电池.测试电池的循环性能和放电性能,并对循环到第10次和第70次的电池在不同放电电压下进行电化学阻抗谱(EIS)研究,提出一种合理的等效电路模型分析锂电极各部分阻抗的变化.结果表明,用13,-二氧戊环处理可使锂电极性能得到较大提高.EIS分析表明,处理后生成的SEI膜结构更稳定,而且与锂基体的界面相容性更好,使电子转移更容易进行.锂负极在循环过程中性能下降的主要原因是其表面膜电阻和电荷传递电阻越来越大,导致锂离子在SEI膜中的迁移阻力增大,电子转移阻力也增大.     

Selective depression action of taurine in flotation separation of specularite and chloriteOA

Chlorite, as the most representative gangue mineral associated with specularite, of which the separation of these two minerals is difficult. This paper investigated the depression effect of taurine on specularite/chlorite separation via flotation experiments, adsorption tests, contact angle measurements, Zeta potential detection, FT-IR measurements, and XPS analyses. The results of single mineral flotation indicated that chlorite could be depressed selectively by taurine with the recovery of les...     

A review of flotation and selective separation of pyrrhotite: A perspective from crystal structures

Pyrrhotite is an associated mineral that exists widely in sulfide ore. The presence of pyrrhotite will affect the recovery of platinum group minerals. Therefore, researchers have paid increasing attention to the flotation separation of pyrrhotite. Pyrrhotite superstructures owning different Fe/S ratios results in various crystal structures, corresponding to different physical, chemical and electronic properties, and consequently different flotation behavior. In the present paper, a comprehensive review is conducted to discuss the influence of crystal structures on the natural floatability, mineral-reagent interaction, surface oxidation and flotation electrochemistry of pyrrhotite. The selective flotation process of pyrrhotite from its associated minerals is also reviewed in this paper. It is hoped that this review can summarize the newly published research results combined with some representative results from the past, to provide a theoretical basis for the study of the flotation mechanism of pyrrhotite and provide a new direction for future research on pyrrhotite.     

Exploration of amino trimethylene phosphonic acid to eliminate the adverse effect of seawater in molybdenite flotation

In this investigation, a chelating agent of amino trimethylene phosphonic acid (ATMP) was introduced to eliminate the adverse effect of seawater in molybdenite flotation. Microflotation results presented that high flotation recovery of molybdenite was achieved in freshwater using kerosene as the collector, but it was significantly decreased in the presence of seawater when pH > 9.5. Among the main ions in seawater, magnesium and calcium ions played a more detrimental role than others. After the addition of ATMP, molybdenite floatability can restore in seawater. Zeta potential distribution and solution chemistry calculation results illustrated that the decreased molybdenite floatability was attributed to the interaction of positive Mg(OH)_2(s) (major) and CaOH⁺ (minor) components with the molybdenite surface. The magnesium/calcium ions of positive components of Mg(OH)_2(s) and CaOH⁺ interacted with the ionized species of ATMP and then produced ATMP-calcium/magnesium complex, leading to the electrostatic repulsion between molybdenite and ATMP-calcium/magnesium complex that was restoring the molybdenite flotation. Hence, the ATMP can be utilized as an appropriate reagent to improve molybdenite flotation in seawater.     

十二烷基硫酸钠在无机盐溶液中的吸附

本文通过测定十二烷基硫酸钠(SDS)及其在无机盐溶液中的表面张力,根据吉布斯吸附方程式应用计算机处理数据,得到的吸附等温线与Brunauel提出的第一类相似.在0.100 0M Mgcl_2或0.100 0M cdcl_2溶液中,SDS的cmc低于无盐存在时的cmc.     

Theoretical study of 2-mercaptobenzimidazole derivatives as chelating collectors in flotation separation of galena and pyrite

Three 2-mercaptobenzimidazole derivatives, 1-ethyl-2-mercapto-benzimidazole (EMBI), 1-propyl-2-mercapto-benzimidazole (PMBI) and 1-benze-2-mercapto-benzimidazole (BMBI), were designed and synthesized in the paper, and their collecting behavior in flotation separation process of galena over pyrite was investigated by flotation tests on lab scale. Apart from this, density functional theory (DFT) calculation and molecular dynamics (MD) simulation were also used to elucidate their collecting mechanism. Results of flotation tests indicate that separation of galena over pyrite is feasible at pH 10, and BMBI has the best floatability among three collectors. DFT calculations show that BMBI has the highest occupied molecular orbital (HOMO) energy and strongest collecting efficiency. The adsorption mode of three collectors on mineral surface by MD method indicates that the combination processes of collectors with mineral are exothermic, and the higher the binding energy, the firmer the collector adsorbs on the mineral surface and the higher collecting capacity. The calculation results demonstrate that the floatability of three collectors follows the order: BMBI > PMBI > EMBI, which is highly consistent with the flotation tests.     

Effect of depressants on flotation separation of magnesite from dolomite and calcite

The flotation separation of magnesite from calcium-containing minerals has always been a difficult subject in minerals processing. This work studied the inhibition effects of carboxymethyl cellulose(CMC),sodium lignosulphonate, polyaspartic acid(PASP) and sodium silicate on flotation behaviors of magnesite, dolomite and calcite, providing guidance for the development of reagents in magnesite flotation.The micro-flotation results showed that among these four depressants, sodium silicate presented...     

环戊烷在Silicalite-1分子筛上吸附的动力学研究

为了探究环戊烷在Silicalite—1分子筛上扩散过程的动力学特性,以及温度、压力等环境因素和吸附质的性质是如何对动力学过程的影响,实验采用重量法测定了环戊烷不同压力下扩散的动力学数据,绘制其在Silicalite—1上的吸附等温线,计算了扩散系数、扩散活化能和活化熵变等动力学参数。结果表明,环戊烷在Silicalite—1上的扩散过程符合Fick第二定律,吸附剂Silicalite—1的特殊孔道结构和吸附质分子的尺寸大小、及分子间的作用,影响着扩散的动力学过程。扩散的活化能、活化熵变和吸附热的变化决定了扩散系数的变化。随着吸附质在沸石上的吸附量增大,吸附热增大,而环戊烷的扩散速率随之降低,并且温度越高,扩散速率越大。     

LDH新型材料的制备和烟气的脱硫性能

在实验室合成了一种层状微孔结构的粘土材料（ＬａｙｅｒｅｄＤｏｕｂｌｅＨｇｈｒｏｘｉｄｅｓ简称ＬＤＨ），并对它在高温下吸附ＳＯ２行为进行了研究。实验结果表明：ＬＤＨ对ＳＯ２吸附容量大，吸附速率快，选择性好，具有较典型的化学吸附特性。通过对三种ＬＤＨ材料在不同温度下ＳＯ２吸附速率的研究，发现各自存在最佳吸附温度。ＬＤＨ材料对ＳＯ２的吸附选择性随温度的升高而增大。同时还研究了ＬＤＨ的再生性能，经再生后的材料，仍具有较好的吸附能力。     

微塑料对抗生素的吸附研究

以土霉素和环丙沙星为目标物,研究其在氯化聚乙烯、聚乙烯和聚氯乙烯上的吸附行为,结果显示:微塑料对抗生素的吸附能力会受到微塑料的性质、抗生素的种类和背景溶液的影响,并且效果极为显著.微塑料对土霉素和环丙沙星的吸附作用的强弱均为:氯化聚乙烯(CPE)>聚氯乙烯(PVC)>(聚乙烯)PE,在纯水环境中PE对土霉素的吸附作用与...     

烷基丙二胺与醚胺组合反浮选石英性能研究

通过N-烷基1,3丙二胺与醚胺组合,得到成本相对较低,浮选泡沫量少的药剂组合。单矿物可浮性试验表明:E1、M1、M3有很好的选择性但药剂用量较大,E2、M2有很好的捕收性,选择性稍差,E3具有较好的选择性和捕收性。通过组合药剂研究,寻找到了组合药剂GE-651C(M1∶E3=7∶3),降低了药剂成本而性能不受影响。实际铁精矿开路浮选表明:GE-651C用量为180 g/t,精矿品位为60.27%,回收率为66.78%。消泡试验表明,GE-651C的泡沫少,性脆易消,有利于泡沫产品的后续处理。