捕收剂CTAB对一水硬铝石与高岭石的浮选差异及其分子动力学模拟

为了研究季铵盐类捕收剂对铝土矿反浮选的影响,以十二胺（DDA）为参照捕收剂,考察了十六烷基三甲基溴化铵（CTAB）对一水硬铝石和高岭石浮选回收率的影响,并通过FTIR分析、Zeta电位检测、吸 附量测定以及分子动力学模拟对作用机理进行了系统的分析。浮选试验结果表明,CTAB浮选分离效果优于DDA,在pH=4、CTAB浓度为2×10-4 mol/L时,纯矿物浮选试验一水硬铝石和高岭石浮选回收率相差51.70个百分 点,人工混合矿试验获得了Al2O3品位71.73%、回收率71.26%、SiO2含量9.43%的精矿,铝硅比A/S达到7.60。机理分析结果表明,捕收剂CTAB在一水硬铝石和高岭石表面均有吸附,在高岭石表面的吸附量大于在一水硬 铝石表面的吸附量,且均为物理吸附;分子动力学模拟计算结果表明捕收剂CTAB与高岭石总相互作用能为与一水硬铝石总相互作用能的2.29倍,因此CTAB分子优先吸附于高岭石的表面,具有较高的选择性,有利于反 浮选的进行。     

新型螯合剂对一水硬铝石和铝硅酸盐矿物浮选行为的研究

合成了含有羧基和肟基的新型螯合捕收剂HCMT并研究其对一水硬铝石、高岭石和伊利石的浮选行为。单矿物浮选试验表明,该捕收剂对一水硬铝石、铝硅酸盐矿物的捕收能力差别较大,能有效分离一水硬铝石与铝硅酸盐矿物。通过动电位、红外光谱和电镜扫描(SEM)等研究了捕收剂对矿物的吸附机理,结果表明捕收剂在一水硬铝石表面可能是通过COOH、-NHOH与Al-O形成双环螯合物的化学吸附,而在高岭石、伊利石表面主要是物理吸附。     

Utilization of soluble starch as a depressant for the reverse flotation of diaspore from kaolinite

The utilization of a non-toxic natural polysaccharide, soluble starch, in the flotation of diaspore and kaolinite with emphasis on depression of diaspore in the reverse flotation of bauxite ores by using a Gemini cationic collector, is reported in this work. Firstly, the depressant effect of soluble starch was studied by pure mineral micro-flotation of diaspore and kaolinite as functions of the depressant dosage and pulp pH. The results show that soluble starch depresses diaspore much better than kaolinite. When pH is over 10, a satisfactory separation of the alumina and the silicate minerals can be approached. Moreover, micro-flotation tests of artificial mixed minerals and bench scale reverse flotation of the diasporic bauxite ore was complementing conducted. The non-charged starch is highly proved to be an effective and selective depressant for the reverse flotation of diaspore from the gangue minerals like kaolinite. By zeta potential measurement, adsorption studies and D-IR spectra analysis, the mechanism of interaction between starch and the diaspore surfaces is established, which is the formation of a five membered ring complexes on mineral substrates. The number of broken Al–O bonds of diaspore is much more than that of kaolinite, so the selectivity separation of diaspore from kaolinite in this system is feasible.     

氧肟酸高分子药剂在铝土矿反浮选中的作用

通过浮选试验，研究了氧肟酸淀粉和氧肟酸聚丙烯酰胺两种高分子药剂对铝土矿中一水硬铝石和高岭石浮选行为的影响。结果表明：氧肟酸淀粉在酸性条件下对一水硬铝石有较强的抑制作用，而对高岭石有活化现象；氧肟酸聚丙烯酰胺在整个试验pH值范围内对两种矿物均有活化作用。两种大分子药剂属于阴离子型，动电位测定结果表明，它们在带负电的高岭石、一水硬铝石表面吸附，使其动电位负性增加，表明药剂与矿物存在氢键力或化学作用力。由于在一水硬铝石表面，氧肟酸淀粉可以罩盖捕收剂十二胺，增加矿物表面的亲水性，从而对其产生抑制作用。而线型氧肟酸聚丙烯酰胺在矿物表面为卧式吸附，其分子链上的负电区能够增加阳离子捕收剂的吸附量，从而活化了一水硬铝石的浮选。     

Preparation and performance of 4-alkyl-4,4-bis(hydroxycarbamoyl) carboxylic acid for flotation separation of diaspore against aluminosilicates

The existed collector for the flotation of diasporic bauxite in China is poor in selectivity. To look for a collector with high selectivity and strong collecting capacity on the diaspore flotation, novel 4-alkyl-4,4-bis(hydroxycarbamoyl) carboxylic acids (ABHC) including 4,4-bis(hydroxycarbamoyl) dodecanoic acid (HCDA), 4,4-bis(hydroxycarbamoyl) tetradecanoic acid (HCTA), and 4,4-bis(hydroxycarbamoyl) hexadecanoic acid (HCHA) were designed and synthesized for the beneficiation of diasporic bauxite by selective flotation. The results of flotation experiments for the single minerals showed that by using these compounds as collectors, the pulp pH value has significant influence on their collecting performance as the floatability of diaspore varies sharply with its change. The appropriate pH value for the flotation of diaspore gets close to neutral condition at which diaspore presents good floatability while kaolinite and illite exhibit poor floatabilities. HCDA, HCTA, and HCHA, especially HCDA, show good selectivity for the flotation between diaspore and aluminosilicate around pH 7. A satisfactory mass ratio of Al₂O₃ to SiO₂ (A/S) and recovery of Al₂O₃ were obtained from the flotation separation of artificially mixed minerals and the flotation desilication of diasporic bauxite by using HCDA as a collector, proving that the selectivity of HCDA is better than that of the traditional collector oleate. Moreover, adsorption amount, zeta-potential, DFT calculation, XPS, and FTIR were performed to study the mechanisms. The results indicated that the adsorption of HCDA on the surface of diaspore is dominantly chemisorption in the form of three chelate rings. The oxygen atoms contained in carboxyl and hydroxycarbamoyl of the polar group have the highly negative charges and stereo conditions to form five- to eight-membered ring, resulting in the coordination of carboxyl and hydroxycarbamoyl to the metal aluminum atoms to form chelate rings. By contrast, the adsorption of HCDA on the surface of kaolinite or illite is mainly physical adsorption.     

二元组合捕收剂浮选分离一水硬铝石与高岭石的机理研究

以油酸钠为主要捕收剂,与苯甲羟肟酸组合使用,复配出二元组合捕收剂,再通过单矿物浮选试验考察二元组合捕收剂对一水硬铝石和高岭石两种铝硅矿物的捕收性能。通过表面张力测定和激光粒度测试,系统研究了二元组合捕收剂的浮选作用机理,旨在为我国铝土矿浮选脱硅捕收剂的开发提供理论指导。结果发现,二元组合捕收剂NaOL/BHA对一水硬铝石和高岭石伴生的铝硅酸盐矿物的浮选效果明显超过单一油酸钠捕收剂,研究的二元组合捕收剂中油酸钠与苯甲羟肟酸的最佳摩尔配比为9∶1。二元组合捕收剂溶液的表面张力随着BHA浓度的增加而下降,在较低浓度下表面张力明显下降到拐点达到稳定值,该现象表明组合捕收剂活性高,捕收性能强,拐点处对应的两种药剂摩尔配比与单矿物浮选实验得出的最佳组合摩尔比一致。二元组合捕收剂可以明显促进一水硬铝石颗粒表观粒度增大,使其形成疏水性聚团,致使浮选回收率增大,而对高岭石表观粒度几乎没有影响。     

调整剂在浮选分离一水硬铝石和高岭石中的研究

单矿物浮选试验结果表明, 在阳离子捕收剂DTAL 作用下, 调整剂SFL 在pH=2～12 范围内活化高岭石的浮选, 而在弱酸性条件下对一水硬铝石的浮选影响较小。弱酸性条件下的人工混合矿分离试验表明, 随着原矿中一水硬铝石的含量的增加, 精矿铝硅比显著上升, 氧化铝的回收率也随着提高;在调整剂SFL 的作用下, 精矿铝硅比进一步提高。动电位测试研究表明, 与SFL 作用后的一水硬铝石和高岭石的负电位显著增加, 使得阳离子捕收剂通过静电作用力更容易吸附在矿物表面上吸附。吸附量的测试表明:SFL增加了在高岭石表面的捕收剂吸附量, 而在一水硬铝石表面的捕收剂吸附量有所减少。     

Role of crystal structure in flotation separation of diaspore from kaolinite,pyrophyllite and illite

Wettability and electrokinetics of kaolinite, illite, pyrophyllite and diaspore were measured in the context of reverse flotation using cationic collectors. The results were interpreted by crystal structure analysis of the minerals. The point of zero charge (PZC) was calculated using crystallographic parameters of the minerals and compared well with the corresponding iso-electrical point (IEP) determined experimentally. The decreasing order of the measured IEP or calculated PZC from diaspore to kaolinite, illite and finally pyrophyllite correlated well with decreasing the number of broken Al–O bonds and the ratio of broken Al–O to Si–O bonds. The electrostatic interaction was identified as the main driving force for cationic collector adsorption on the minerals. Satisfactory separation of aluminosilicates from diaspore was achieved by reverse flotation.     

Synthesis and collecting properties of novel carboxyl hydroxamic acids for diaspore and aluminosilicate minerals

Novel carboxyl hydroxamic acids compounds, including 2-carboxyl-6-methylcyclohexane carboxamic acid (CMCA), 2-carboxymethyl-decylen-4-yl hydroxamic acid (CDHA), and 2-carboxymethyl-tetradecen-4-yl hydroxamic acid (CTHA) were synthesized, and the flotation behaviors of diaspore, kaolinite and illite were investigated by using these compounds as collectors. The adsorption mechanism of CTHA on the surface of diaspore, kaolinite and illite was conducted by zeta-potential, adsorption amount and FTIR spectra measurement. The interaction of CTHA on the diaspore surface may be mainly dominated by the chemical adsorption; however, the adsorption of CTHA on kaolinite or illite is mainly dominated by the physical one.     

新型阳离子有机硅QAS222对铝硅矿物浮选行为的研究

考察了自行合成的新型有机硅阳离子表面活性剂QAS222对一水硬铝石、高岭石、叶蜡石和伊利石等4种铝硅矿物的浮选行为,并以其为铝硅酸盐矿物的捕收剂,进行了不同铝硅比的人工混合矿反浮选分离脱硅试验研究。试验研究结果表明,新型阳离子有机硅季铵盐类化合物是铝土矿反浮选脱硅的有效捕收剂;酸性条件下QAS222对一水硬铝石、高岭石、叶腊石和伊利石表现较好的捕收力,但此时反浮选分离趋势不明显;而在碱性条件下,以QAS222为捕收剂,随着矿浆pH值的上升,4种矿物的可浮性出现了不同程度的减低,尤其是当矿浆pH9后,一水硬铝石的上浮率骤减,铝硅矿物之间表现出了良好的反浮选分离趋势;在矿浆pH值为11时,以QAS222为捕收剂,不添加其它任何抑制剂,成功地实现不同铝硅比的人工混合矿的反浮选脱硅,并获得较好的选别指标——当给矿A/S仅有2.7时,仍能获得精矿A/S为12.82,其中Al2O3品位77.79%、回收率69.91%的较好指标,且当给矿A/S不断增大时,精矿中的A/S,Al2O3的品位和回收率都有所提高。     

The behavior of N,N-dipropyl dodecyl amine as a collector in the flotation of kaolinite and diaspore

The flotation behaviors of kaolinite and diaspore were investigated using N,N-dipropyl dodecyl amine (PN). Maximum recoveries of kaolinite and diaspore were about 90% and 50%, respectively. Both recoveries of kaolinite and diaspore increased with the increasing dosage of PN. On the basis of the zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions account for the charging mechanisms of surfaces of kaolinite and diaspore. The adsorption mechanism of PN on the surface of two minerals was mainly electrostatic. After reacting with PN, the zeta potential of kaolinite and diaspore both increased, and comparing with the original zeta potentials, potential of kaolinite increased much more than that of diaspore, this can explain why recovery of kaolinite is higher than that of diaspore.     

季铵盐捕收剂对铝硅矿物的浮选行为

通过单矿物浮选试验、动电位测定及红外光谱分析研究了十二烷基三甲基氯化铵、十六烷基三甲基溴化铵和十八烷基二甲基苄基氯化铵3种季铵盐捕收剂对铝硅矿物一水硬铝石、高岭石、叶蜡石和伊利石的浮选行为和作用机理.结果表明:在碱性条件下,以季铵盐为捕收剂可实现一水硬铝石与3种硅酸盐矿物的反浮选分离;一水硬铝石、高岭石、叶蜡石及伊利石的等电点分别为pH6.0、3.4、2.3、3.2,随着矿浆pH值提高,这些矿物的表面动电位均呈负增加;季铵盐捕收剂主要靠静电作用吸附在一水硬铝石、高岭石、叶蜡石及伊利石表面.     

粒度对一水硬铝石和高岭石浮选分离的影响

研究了不同粒度一水硬铝石和高岭石的浮选行为,结果表明:油酸钠作捕收剂时,随着粒度的变细,一水硬铝石的上浮率变小,十二胺作捕收剂时,情况相反;高岭石的上浮率变化规律与一水硬铝石相反。人工混和矿试验表明:采用油酸钠和十二胺正、反浮选分离一水硬铝石和高岭石要尽量放粗两者的入选粒度,才能达到较好的分选效果。     

十二胺捕收剂在三种不同矿物表面吸附的分子动力学模拟

采用Materials Studio中的Forcite模块,对水分子和十二胺捕收剂分子在锂云母、长石和石英三种不同矿物表面的吸附过程进行了分子动力学模拟研究,分析了吸附前后水分子在三种矿物表面的浓度分布。结果表明,三种矿物均具有类似的亲水特性,水分子在三种不同矿物表面吸附没有选择性。相反,比较了十二胺捕收剂在锂云母、长石和石英三种不同矿物表面的吸附情况,结果表明十二胺捕收剂能够选择性吸附在锂云母表面,从而改变其表面亲水性,达到与长石、石英分离的目的,阐明了十二胺捕收剂的吸附对于锂云母表面的亲水性改变极为有效。从理论上通过模拟接触角的变化,验证了烷基胺捕收剂浮选锂云母的这一过程。     

A novel surfactant 2-amino-6-decanamidohexanoic acid: Flotation performance and adsorption mechanism to diaspore

In this paper, a novel surfactant, 2-amino-6-decanamidohexanoic acid (AHA-10) was synthesized and used as a collector for flotation separation of diaspore and aluminosilicate minerals. The adsorption mechanism of AHA-10 onto diaspore was also evaluated by FTIR spectra, zeta potential, XPS and solution chemistry. The flotation results demonstrated that AHA-10 exhibited superior collecting power to diaspore and good selectivity against kaolinite and illite, and could effectively recover diaspore from bauxite ores contained aluminosilicate minerals at pH around 10. The analyses of FTIR spectra, zeta potential and solution chemistry inferred that at pH around 10, AHA-10 might chemisorb on diaspore surfaces by formation of AlO and AlN bonds. AHA-10’s unique properties, such as characteristic bond model to Al atoms on diaspore surfaces, double hydrophobic groups and intermolecular hydrogen bonds between neighboring AHA-10 molecules coated on diaspore surfaces, rendering a weakening surface energy and enhancing hydrophobicity of diaspore particles.     

铝土矿浮选新型捕收剂的捕收性能及机理研究

通过一水硬铝石和高岭石的单矿物浮选试验、接触角、红外光谱、和ζ电位测量分析了东北大学研制的DJL-1和DJL-2捕收剂在铝土矿正浮选中的浮选行为和作用机理。一水硬铝石与DJL-1和DJL-2作用后接触角变大、疏水性变强;高岭石与DJL-1作用后接触角几乎不变,与DJL-2作用后接触角变大。DJL-1使一水硬铝石和高岭石表面ζ电位均负向增加,DJL-2对一水硬铝石和高岭石表面ζ电位影响较小,分别使用DJL-1和DJL-2,一水硬铝石和高岭石的最大回收率之差为54.5%和70.5%,DJL-2在更宽的温度和pH范围内获得更好的浮选结果;DJL-1和DJL-2在一水硬铝石表面存在键合吸附和氢键作用,DJL-1与高岭石表面存在氢键作用。结果表明,DJL-1和DJL-2均是铝土矿正浮选的优良捕收剂,且DJL-2更优。     

氟化钠在铝硅酸锌矿石物浮选新工艺试验研究

在季铵盐捕收剂体系中，氟化钠活化了层状硅酸盐矿物高岭石、伊利石和叶蜡石的浮选，而对一水硬铝石的浮选没有影响，可以作为铝土矿反浮选的有效调整剂。氟化钠在矿物表面上发生特性吸附作用，显著降低硅酸盐矿物的Zeta电位，而对一水硬铝石的电位影响不大。AES研究表明，氟离子扩散至硅酸盐矿物颗粒内部，使得其在硅酸盐矿物颗粒上的吸附量很高，而只在一水硬铝石表面发生较低量的吸附。氟离子在硅酸盐矿物颗粒的表面和内部的高吸附量显著降低矿物的动电位，增强捕收剂与矿物的静电作用，从而起到活化作用。     

选择性抑制剂BK501A在铝土矿反浮选脱硅中的应用

通过浮选试验、絮凝试验、动电位和红外光谱测定,详细考察了抑制剂BK501A在一水硬铝石与高岭石反浮选分离中的作用效果和机理。浮选试验表明,通过加大药量,一水硬铝石在广泛的pH范围内被抑制,而对高岭石的可浮性影响很小。机理分析表明,药剂通过氢键与一水硬铝石强烈作用,产生亲水性絮凝,从而使其被抑制。     

可溶性淀粉在长石与石英浮选分离中的作用

通过单矿物浮选实验、动电位测试及吸附量的测定，揭示了可溶性淀粉在长石与石英浮选分离中的作用。结果表明:采用十二胺（DDA）和十二烷基磺酸钠(SDS)作为混合捕收剂，可溶性淀粉对长石与石英皆有抑制作用，相对而言可溶性淀粉对石英的抑制作用较强，对长石的抑制作用较弱；动电位测试表明，长石在可溶性淀粉中的zeta电位相对于在纯水中的zeta电位只是略微向正方向移动，pH值为 5～7的范围内，石英在可溶性淀粉溶液中的zeta电位明显向正方向移动；吸附量的测定结果表明，在中性矿浆条件下，淀粉用量在20-80 mg/L的范围内，其在石英表面的吸附量大于在长石表面的吸附量，淀粉阻碍了捕收剂在石英表面的吸附，因此淀粉能够有效地抑制石英，而对长石抑制作用较弱。      

一水硬铝石与高岭石反浮选分离研究

详细研究了一水硬铝石和高岭石的浮选行为 ,并以十二胺盐酸盐作为捕收剂 ,在酸性介质 ( pH3 .5 )及中性介质 ( pH7.5 )加调整剂ATNO进行反浮选分离研究 ,得到较好的分离效果 ,精矿A/S >11。同时进行了不同粒级和不同A/S的一水硬铝石和高岭石的反浮选分离 ,结果表明 ,不同的A/S条件下 ,可以得到较好的分离效果 ,但粒级对一水硬铝石和高岭石的分离有较大的影响 ,细粒级一水硬铝石与高岭石分离效果不好 ,有待于进一步研究