N-十二烷基乙二胺在石英表面的吸附机理

采用单矿物浮选试验探讨了N-十二烷基乙二胺(ND)对石英的捕收性能,通过动电位测试、X-射线光电子能谱分析和表面自由能计算分析其在石英表面的吸附机理.结果表明,与十二胺相比,ND对石英具有更好的捕收能力,在捕收剂用量为41.7mg/L,pH=6.6时,石英回收率达到最大值98.10%.表面自由能计算结果表明,石英表面吸附ND后的表面自由能明显降低,疏水性增强;X射线光电子能谱分析和动电位测试结果表明,ND与石英表面主要发生了静电和氢键吸附.     

阴离子淀粉对一水硬铝石和伊利石浮选行为的影响

通过浮选实验、动电位和吸附量测定,考察了阴离子淀粉在一水硬铝石和伊利石浮选分离中的效果与作用机理.单矿物浮选实验表明,在阳离子捕收剂(DTAC)体系中,阴离子型淀粉(LSDZ)在pH=4～11的范围内抑制了一水硬铝石的浮选.当pH=6,c(DTAC):3×10-4 mol/L时,随着阴离子淀粉LSDZ用量的提高,一水硬铝石被抑制;当c(LSDZ)＜40 mg/L时,活化伊利石的浮选,继续提高淀粉用量,则伊利石被抑制.结果表明:阴离子淀粉是反浮选分离一水硬铝石和伊利石的有效调整剂,LSDZ通过氢键与静电力作用吸附在铝硅矿物表面,阳离子捕收剂使矿物表面ζ-电位正移,阴离子淀粉使矿物表面ζ-电位负移,且阴离子淀粉的加入能促进捕收荆DTAC在矿物表面的吸附.     

铝硅酸盐矿物浮选中捕收剂的设计合成及浮选机理的研究

铝土矿中脉石主要为高岭石、伊利石和叶蜡石等铝硅酸盐矿物,可以采用反浮选脱硅即通过选用合适的捕收剂将这些脉石矿物浮出.本文针对某铝土矿,结合Curis2软件中的高岭石晶体模型分析,从亲矿物基和非极性基两方面设计合成多胺类捕收剂DN12.通过浮选实验、浮选溶液化学计算、动电位测定和红外光谱测定研究该新型药剂对铝硅酸盐矿物的浮选作用及其机理.该捕收剂相对于常规捕收剂对铝硅酸盐矿物有更好的捕收效果,有效浮选pH区间为4~10.该捕收剂与铝硅酸盐矿物的作用以静电作用为主,同时也有氢键作用,从而增强了对矿物的捕收能力.     

辛基羟肟酸浮选锡石的机理

为探明辛基羟肟酸对锡石的捕收性能及其吸附机理,本文通过单矿物浮选实验,考察了辛基羟肟酸、水杨羟肟酸和苯甲羟肟酸体系中锡石的浮选行为,通过吸附量测定、红外光谱测试、动电位、光电子能谱分析、溶液化学计算研究了辛基羟肟酸对锡石的作用机理.浮选实验结果表明:辛基羟肟酸对锡石的捕收能力明显强于水杨羟肟酸和苯甲羟肟酸,当辛基羟肟酸质量浓度为50mg/L,pH为10左右时,锡石的回收率最高达到91.79%.吸附量测试结果显示:在pH为10时,辛基羟肟酸在锡石表面的吸附量最大为0.23mg/g,与浮选结果一致.XPS分析,Zeta电位和红外光谱测试结果表明:辛基羟肟酸在锡石表面主要发生化学吸附,同时也可能存在物理吸附.辛基羟肟酸的溶液化学计算得出:对锡石浮选起主导作用的是离子-分子缔合物.辛基羟肟酸在锡石表面形成强疏水性的缔合物,可作为锡石的强效捕收剂.     

表面预处理对锂辉石和硅酸盐矿物浮选的影响

通过浮选试验、量子化学计算、接触角测量、ICP-MS检测以及溶液化学分析,研究了锂辉石和硅酸盐矿物表面预处理及其溶解组分对其浮选行为的影响及机理.结果表明:经氢氧化钠预处理后,锂辉石与长石、石英之间的可浮性差异增大;氢氧化钠预处理过程中,锂辉石、长石和石英表面组分的溶解速度不同,其大小顺序为锂辉石、长石、石英,即在碱性环境中锂辉石的表面组分会优先溶解.经表面预处理后,锂辉石表面对油酸钠的吸附作用增强,可浮性得到提高.矿物表面组分溶解后,在弱酸及弱碱性条件下,Al溶解的优势组分为Al(OH)_(3(s))和Al(OH)_(3(aq)),有利于提高矿物的可浮性,而Si溶解的优势组分则为Si(OH)_4和SiO(OH)~-_3,会降低矿物的可浮性.     

利用亚油酸组分选择性浮选分离一水硬铝石与叶腊石

为解决叶腊石与一水硬铝石的选择性浮选分离,采用浮选试验、分子模拟计算及动电位测定等方法,开展了一水硬铝石和叶腊石浮选行为及药剂与矿物间相互作用的研究.浮选试验表明:用碳酸钠和六偏磷酸钠做调整剂时,随油酸碘值的增大,其捕收能力和选择性均增强.对m(Al_2O_3)∶m(SiO_2)为3.39的铝土矿,用碘值为131的油酸做捕收剂,经两粗三精两扫浮选流程,闭路试验获得精矿m(Al_2O_3)∶m(SiO_2)为5.33,Al_2O_3回收率为85.56%的良好指标.研究表明:随油酸碘值增大,亚油酸含量增大.亚油酸比油酸更易与一水硬铝石表面的Al原子作用,体现出更强的捕收能力和更好的选择性.     

油酸钠浮选高岭石的溶液化学机理研究

通过单矿物浮选实验、浮选溶液化学计算、Zeta电位测试和红外光谱分析研究了油酸钠对高岭石浮选行为的影响以及溶液化学作用机理,旨在为阴离子捕收剂高效浮选高岭石以及铝土矿正浮选提供理论指导.通过高岭石溶解组分的浓度对数图(lg c-pH)理论推算出高岭石零电点PZC=4.52,较Zeta电位所测值(PZC=3.9)偏高,与文献利用AFM所测的高岭石PZC=4～5一致.通过油酸钠溶液各组分的浓度对数图(lg c-pH)可知,形成最大浓度离子-分子缔合物的pH值为8.44,其与最佳浮选pH一致,此时高岭石表面Zeta电位负移也最显著,说明离子-分子缔合物的浮选活性最大.加入阴离子捕收剂油酸钠后高岭石表面Zeta电位整体向负移,说明油酸钠通过非静电力吸附在高岭石表面.结合红外光谱测试结果推断油酸钠与高岭石可能发生化学吸附.     

李楼铁矿常温阴离子捕收剂反浮选

为了得到常温反浮选铁矿脱硅脂肪酸阴离子捕收剂,实现常温反浮选,通过植物油脂肪酸原料的选取,磺化、氧氯化反应再复配阴离子表面活性剂,制备阴离子型捕收剂.以李楼铁矿工业生产的二段强磁尾矿试验样品,进行了常温反浮选脱硅.试验结果表明,以棉油脂肪酸为原料合成的捕收剂的浮选性能优于米糠油脂肪酸和玉米油脂肪酸;在药剂中复配少量的表面活性剂MES能提高药剂的捕收性能;采用反浮选工艺流程,在矿浆温度为17℃条件下,获得了铁精矿全铁质量分数65.91%,产率62.76%,回收率91.61%的浮选指标.     

MES的合成及其磷矿浮选性能评价

以油酸为原料,经酯化、磺化及中和处理制得了脂肪酸甲酯磺酸钠(MES).通过考查捕收剂、抑制剂和调整剂用量对其浮选性能的影响,表明其用作磷矿捕收剂的浮选性能与油酸钠基本相当,不同的是其选择性更好,抗硬水能力更强,因此可以减少浮选所需的水玻璃和碳酸钠用量.但其捕收能力相对较弱,所需用量较大,浮选泡沫量较多.会对磷矿浮选产生不利影响.     

利用纯化棉籽油酸的铁矿石常温反浮选

为了解决铁矿石阴离子加温反浮选的高能耗问题,利用尿素包裹法分离纯化的棉籽油酸复配的捕收剂进行了常温（１５ ℃）反浮选试验． 以齐大山铁矿磁铁精矿为反浮选研究对象, 确定了最佳药剂耗量为:粗选氢氧化钠 ０．７ ｋｇ／ｔ、淀粉０．４ ｋｇ／ｔ、氯化钙０．１ ｋｇ／ｔ、捕收剂０．４ ｋｇ／ｔ、扫选淀粉０．２ ｋｇ／ｔ．开路获得铁精矿品位６３．６４％、回收率４７．８８％,并经过闭路试验得到铁精矿品位６３．７５％、回收率 ８９．４７％的选矿指标． 试验表明纯化后的棉籽油酸常温捕收能力增强,复配16.7％阴离子表面活性剂后捕收能力进一步增强． 为解决常规加温反浮选能耗大,成本高的问题提供了一条可能的途径．     

Flotation of quartz using N-(2-aminoethyl)-octadecanamide as collector

1　INTRODUCTIONMuchworkhasbeendoneonthefrothflotationofquartzinRefs .[1 6 ].Bothcationicandanioniccollectorsareemployedinquartzflotation .Ingener al ,thecollectorsarelong chained ,withatleasttencarbonatoms presentinthehydrocarbon portion .Cationiccollectorscommonlyutilizedareamines ,in cluding primaryamines ,secondaryamines ,tertiaryamines,quaternaryammoniumsalts ,sulphoniumsalt,alkylpyridiniumsaltsanddiamine .Foranioniccollec tor ,thecommonlyused ,arecarboxylate ,sulphonate ,alkylsulpha…     

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.     

Physical chemistry mechanisms of CDR system in sulphide mineral flotation

The flotation tests,zeta potential measurements,and Fourier transform infrared spectroscopy(FTIR) analysis on galena,sphalerite,and pyrite were studied in a collecting-depressing-reactivating(CDR) system.In this system,sulphide minerals were first collected and acti-vated by the collector,and then depressed strongly by Ca(OH)2 in a strong alkaline solution.Finally,they were reactivated by H2SO4.The flotation tests of pure minerals showed that in the Ca(OH)2 depressing process sulphide minerals had similar flotation characteristics because they had already been influenced by the collector.Hence,the flotability differences between them were reduced.However,in the H2SO4 re-activating process considerable differences in the flotability between galena and sphalerite/pyrite were produced.That is to say,galena was relatively easy to be reactivated by H2SO4,but sphalerite and pyrite were not reactivated at pH 11.The zeta potentials of sulfide minerals measured by the Zeta Plus presented irreversible characteristics on the change of pH values.The results of the FTIR spectra analysis indi-cated that the collectors already adsorbed on the mineral surface were removed partially by Ca(OH)2.     

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.     

Effect and mechanism of siderite on reverse anionic flotation of quartz from hematite

Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of reverse flotation of hematite are poor in presence of siderite using fatty acid as collector, starch as depressant of iron minerals and calcium ion as activator of quartz at strong alkaline pH. In this work, the effect of siderite on reverse anionic flotation of quartz from hematite was investigated. The effect mechanism of siderite on reverse flotation of hematite was studied by solution chemistry, ultraviolet spectrophotometry(UV) and Fourier transform infrared spectroscopy(FTIR). It was observed that siderite had strong depressive effect on quartz in flotation using sodium oleate as collector, corn starch as depressant of iron minerals and calcium chloride as activator of quartz at strong alkaline pH. The starch was adsorbed onto calcium carbonate by chemical reaction which was formed by CO~(2-)_3 from siderite dissolution and Ca~(2+) from calcium chloride as activator of quartz and precipitated on the surface of quartz, which resulted in improving the hydrophilic ability of quartz.     

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...     

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

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 less than 30%, but the floatability of specularite remains high with recovery rate of 81.77% at pH 10. The artificial mixed mineral flotation results confirmed the effectiveness of taurine as a depressant. Surface adsorption, contact angle, and Zeta potential detection revealed taurine primarily adsorbs on the chlorite surface, which hampered the DDA’s subsequent adsorption and results in the chlorite’s poor floatability. The FT-IR spectra and XPS analyses provided further proof that taurine adsorbed on chlorite surface as an electron donor, and part of the electrons transferred from the sulfonic acid group of taurine to metal ions during the adsorption process. In addition, the hydrogen bond between amino-group of taurine and O ions in chlorite surface was also formed in the adsorption process. Finally, optimized adsorption configurations of taurine on chlorite surfaces were proposed.     

Influences of collector DLZ on chalcopyrite and pyrite flotation

The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments, zeta potential measurements and infrared spectrum analysis. Flotation test results indicate that DLZ is the selective collector of chalcopyrite. Especially, the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems, while the recovery of pyrite is less than 10%. When using CaO as pH regulator, at pH=7-11, the floatability of pyrite is depressed and the recovery is less than 5%. Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ, confirming that collector DLZ shows selectivity to chalcopyrite and pyrite. And FT1R results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.     

不同成因磷灰石可浮性的研究

对五种不同成因磷灰石的浮选行为与表面,溶解速度,油酸钙沉淀和油酸盐吸附量等之间的关系作了系统研究。实验表明,磷灰石的溶解速度,油酸钙沉淀量及充分浮选所需油酸钾浓度都与磷灰石的比表面积有关。 沉积型磷灰石有较大比表面积,在水溶液中溶下较多量ca~(2+)离子,生成较多油酸钙沉淀,充分浮选时需较高油酸钾浓度。 充分浮选时,捕收剂在五种不同磷灰石表面的复盖率看来是相近的,都有油酸钙沉淀生成,这与ca~(2+)离子从磷灰石表面溶下速度及达到一定复盖率时所需的捕收剂浓度有关。     

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.