辛醇对苯甲羟肟酸浮选锡石的影响和机理（英文）

研究了辛醇对苯甲羟肟酸(BHA)浮选锡石纯矿物的影响,分析了辛醇和BHA在锡石表面的吸附机理。实验室浮选实验结果表明,在广泛pH区间内,单一辛醇对锡石没有浮选性,但是作为辅助捕收剂,辛醇可以显著降低捕收剂BHA的用量,并且使锡石仍保持较高回收率。红外光谱和吸附量研究表明,单一辛醇在锡石表面没有发生吸附,但是辛醇与BHA形成吸附组合体而吸附在锡石表面,增强了锡石表面的疏水性;同时辛醇使BHA在锡石表面的吸附量增加,从而降低了BHA的用量。     

季铵型阳离子捕收剂在一水硬铝石和高岭石表面的吸附机理

研究十二烷基三甲基氯化铵（DTAC）和十六烷基三甲基氯化铵（CTAC）对一水硬铝石和高岭石的浮选行为。通过残余浓度法测定吸附等温线,荧光探针法和Zeta电位测试方法研究季铵型阳离子捕收剂在矿物表面的吸附机理。浮选结果表明：将DTAC和CTAC作为捕收剂,一水硬铝石的浮选回收率随着pH的增大而增加,而高岭石的浮选回收率随着pH的增大反而下降。当捕收剂的碳链增长时,矿物浮选回收率提高,但高岭石的增加幅度小于一水硬铝石的。在低浓度范围内,阳离子表面活性剂通过静电作用吸附在一水硬铝石表面,而对于高岭石,还存在离子交换作用。当浓度增大时,阳离子表面活性剂通过碳链间疏水缔合作用在两种矿物表面进一步吸附。矿物表面微极性研究表明：CTAC的疏水性比DTAC强,相同溶液浓度下CTAC在一水硬铝石表面能形成比在高岭石表面更大的胶团,这也说明阳离子表面活性剂碳链的增长对一水硬铝石吸附的影响要大,与浮选结果相吻合。     

十二烷基胍对铝硅矿物的浮选分离

采用含有胍基的长碳链季铵盐作捕收剂,研究-水硬铝石、高岭石、叶腊石和伊利石单矿物的浮选行为、铝硅人工混合矿样的浮选分离以及河南铝土矿的精选.结果表明:在捕收剂用量为2×10-4mol/L条件下,在广泛的pH范围内,十二烷基胍对硅酸盐矿物具有较好的捕收能力,平均浮选回收率可达80%;强碱性条件下,一水硬铝石的浮选回收率从80%急剧下降至20%,与高岭石、叶腊石和伊利石之间形成较大差异:以十二烷基胍为捕收剂可望实现铝硅矿物反浮选分离:实际铝土矿(原矿铝硅比为5.70)经过反浮选脱硅,精矿铝硅比达11.08,铝浮选回收率为75%;与传统的阳离子捕收剂十二胺相比,胍类阳离子捕收剂对硅酸盐矿物浮选能力强、受pH的影响小,是一种新型高效的铝硅矿物浮选分离捕收剂.     

组合羟肟酸下方解石和萤石中浮选氟碳铈矿的分离机理

苯甲羟肟酸(BHA)和辛基羟肟酸(OHA)以及二者组合羟肟酸(BHA+OHA)下,对氟碳铈矿、方解石、萤石三种矿物进行了浮选研究。通过红外光谱分析、总有机碳和紫外光谱吸附量测试和XPS分析研究了羟肟酸类在矿物表面的作用机理。结果表明：在pH=9.5、组合捕收剂(n(BHA)∶n(OHA)=2∶1)浓度为3×10^-4 mol/L和盐化水玻璃3×10^-3 mol/L条件下,氟碳铈矿、方解石和萤石的回收率分别为89.8%、18.5%和13.7%,人工混合矿REO品位由28.90%提升至55.41%,氟碳铈矿的回收率为80.41%,与方解石和萤石实现较好分离;组合捕收剂(BHA+OHA)在三种矿物表面发生共吸附,且组合捕收剂中每种药剂的吸附率大于相同浓度的单一药剂;盐化水玻璃阻碍捕收剂在方解石、萤石表面的吸附对捕收剂在氟碳铈矿表面吸附无影响,可以达到抑制方解石和萤石的目的,实现氟碳铈矿的选择性浮选。     

西峡红柱石矿石的浮选分离

研究应用不同捕收剂时红柱石的浮选行为。采用西峡红柱石纯矿物进行微型浮选试验,利用红柱石矿石进行小型浮选试验,测定纯红柱石表面的电荷。结果表明,红柱石的等电点为pH5.2。在pH值高于等电点时,矿物表面带负电荷,可用胺类捕收剂浮选红柱石。相反,红柱石表面带正电荷,用烷基磺酸盐捕收剂（十二烷基苯磺酸钠）浮选红柱石比较有效。在中性和弱碱性pH范围时用油酸盐可以浮选红柱石。用烷基磺酸盐捕收剂时可以获得含55.3%Al2O3,红柱石回收率为75.6%的红柱石精矿。在用烷基磺酸盐捕收剂时,淀粉是脉石矿物的有效抑制剂。此外,试验发现矿泥对红柱石浮选有不利影响。因此,浮选前必须脱碳和脱泥。     

钛渣中钙钛矿的浮选分离及其机理

研究了捕收剂油酸、羟肟酸、十二烷胺双甲基膦酸 ,抑制剂氟硅酸钠、水玻璃对改性渣中钙钛矿浮选的影响。通过浮选溶液化学计算、矿物动电电位、红外光谱等研究 ,探讨了羟肟酸在钙钛矿表面的作用和水玻璃抑制钛辉石的作用机理。结果表明 :以羟肟酸为捕收剂 ,水玻璃为抑制剂可实现钙钛矿与钛辉石等的浮选分离。钙钛矿和钛辉石晶体表面的Ca,Ti质点密度不同 ,所处的位置及活性不同 ,造成二者浮游性有一定的差异 ;钙钛矿在整个研究范围内 ζ电位始终为负值 ,但在阴离子捕收剂C5-9羟肟酸中可浮性良好 ,表明C5-9羟肟酸在钙钛矿表面发生了化学吸附。红外光谱研究证实 ,C5-9羟肟酸的CN ,N—O官能团与钙钛矿表面的钛质点发生了化学键合。     

苯甲羟肟酸在浮选中的应用及作用机理研究进展

苯甲羟肟酸(Benzohydroxamic acid,简称BHA)是一种具有良好选择性的氧化矿捕收剂,近年来在浮选中得到了广泛的应用。本文介绍了BHA的物理化学性质,梳理了BHA及其衍生物在矿物浮选中的应用,总结了BHA在矿物表面的吸附机理。结果表明：BHA是一种与金属离子容易形成杂环配合物的螯合剂,在白钨矿、锡石、钛铁矿、稀土矿物等矿物的浮选中已经广泛使用。BHA主要通过与矿物表面金属位点形成O, O五元环配位结构产生稳定吸附,其吸附性能与溶液中组分BHA-的含量息息相关。金属离子活化能显著提高BHA的捕收性能,分为经典金属离子活化和金属离子有机配合物活化两种形式,以BHA金属离子配合物作为捕收剂是金属离子活化的优选方案。基于以上结论,对BHA未来的研究趋势及重点进行了展望。     

羟肟酸类捕收剂在中低品位铝土矿浮选中的性能研究

拜耳法氧化铝生产工艺已在我国大规模应用,其中铝土矿选矿是关键环节,而对于我国中低品位的铝土矿资源,需要研究一种更适合我国铝土矿选矿使用的浮选药剂.本文讨论了羟肟酸类捕收荆在中低品位铝土矿浮选中的应用与适用条件.分别用苯甲羟肟酸、对甲苯甲羟肟酸、1-羟基-2-萘甲羟肟酸三种物质作捕收剂进行了铝土矿浮选试验,得出了羟肟酸类捕收剂的浮选性能与pH值的关系,讨论了在适宜的pH值下三种药荆的浮选性能与药荆用量的关系.比较了三种药剂的浮选效果,并解释了三种药剂的浮选性能的差别.     

锡石颗粒与氢气泡间的碰撞粘附行为(英文)

运用回收率和细粒锡石-气泡间的碰撞机制研究颗粒-气泡间的相互作用。用单泡浮选管进行浮选实验,考查不同条件下细粒锡石的浮选行为。结果表明,浮选回收率受颗粒和气泡尺寸的影响很大,在浮选回收率最高时,颗粒和气泡间存在一个最佳的匹配范围。运用高速摄影仪观察并捕捉颗粒-气泡间的碰撞、粘附、脱附过程,在已有理论的基础上,分析颗粒-气泡间的碰撞-粘附现象并解释浮选实验结果,通过捕捉图片证明颗粒-气泡间的粘附模型,发现颗粒-气泡间的桥连作用。锡石、气泡尺寸的大小影响锡石-气泡间的相互作用,这不仅影响锡石-气泡间的碰撞粘附行为,并最终影响细粒锡石的浮选回收率。     

新型白钨矿分离羟肟酸捕收剂的分子设计

采用密度泛函理论模拟计算白钨矿(001)和萤石(111)解理面的结构特征及空间质点分布,并通过对羟肟酸与矿物表面吸附构型的分析,指出羟肟酸中非极性基对极性基官能团结构的影响会继而影响羟肟酸对白钨矿和萤石的选择性。论文基于该思路设计并合成一种新型的6-邻环己烷二甲酰亚胺基己基羟肟酸捕收剂(DIHHA)。通过核磁共振、元素分析以及红外光谱对合成产品进行表征,并对环己烷羟肟酸(CHA)进行了捕收剂的纯矿物浮选实验以及人工混合矿浮选实验。结果表明:DIHHA显示出比CHA更佳的选择性,是一种极具前景的白钨矿-萤石分离捕收剂。该实验结果与理论计算推测结果非常吻合,证明采用密度泛函理论模拟计算矿物晶体表面及捕收剂分子空间结构,并结合吸附构型分析,能够为捕收剂分子设计提供有效指导。     

Influence of metal cations on cassiterite flotation

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Flotation Behavior and Mechanism of Anglesite with Salicyl Hydroxamic Acid as Collector

The flotation behavior of anglesite at different pulp pH levels was studied, with salicyl hydroxamic acid (SHA) acting as collector. The results demonstrated the effectiveness of SHA over a wide pH range. Zeta potential, adsorption, and x-ray photoelectron spectroscopy measurements were carried out to explore the interactions between SHA and anglesite. The results showed that the adsorption of SHA on the surface of anglesite was both chemical and physical. Furthermore, experiments with a bench-scale closed-flotation circuit proved that the collector can effectively recover anglesite from zinc-leaching residues (ZLRs). This work sheds new light on flotation of anglesite, providing a significant contribution to understanding of anglesite flotation and its application for disposal of ZLRs.     

Corrosion protection properties of hydroxamic acid self-assembled monolayer on carbon steel

Self assembled monolayers (SAMs) of hydroxamic acids CH₃(CH₂)_nCONHOH with different alkyl length were formed on the carbon steel electrode surface. The corrosion protection properties of the monolayers were examined and characterized by electrochemical polarization curves, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy (XPS) and contact angle measurements. XPS results showed that the hydroxamic acid molecules adsorbed on the carbon steel surface, and the contact angle values on the modified surface supported the formation of hydrophobic hydroxamic acid SAMs. The results of electrochemical studies showed that the values of the corrosion potential shift towards the positive direction, and anodic currents of the carbon steel dissolution significantly decreases, indicating that hydroxamic acids are anodic inhibitors. However, the chain length and assembling time influence the protection efficiency.     

Interaction and flotation of diaspore with alkylamine hydrochlorides

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Effect of biological pretreatment on flotation recovery of pyrolusite

Bacillus mucilaginosus was used in pretreatment of pyrolusite to facilitate the flotation removal of quartz from pyrolusite minerals. Quartz was activated by B. mucilaginosus, whereas pyrolusite was unaffected at pH 7 with laurylamine as collector. Flotation recovery of pyrolusite with B. mucilaginosus pretreatment is 73.62%, slightly lower than that of the process without biopretreament, namely 74.70%. The grade of concentrate of recovered pyrolusite is 19.44%, 2.18% higher than that of the recovered pyrolusite without B. mucilaginosus pretreatment (17.26%). The results of FTIR and SEM showed that no bacteria were adsorbed on the surface of quartz or pyrolusite, indicating that the better selectivity and collectability of flotation resulted from bacterial byproducts. And interaction of bacterial byproducts such as extracellular bacterial polysaccharide, extracellular bacterial protein and acetic acid, on minerals were studied by FTIR and adsorption.     

A new collector used for flotation of oxide minerals

A surfactant containing a mixed aliphatic structure, with a hydrocarbon chain and a diamine group, has proven to be collector for the flotation of quartz, calamine and calcite. And research about its collecting capability was carried out in laboratory. The test results show that the flotation recovery ascends sharply with increasing the concentration of collector. When the concentration of collector reaches 1.83×10⁻⁴ mol/L, the flotation recoveries of quartz, calamine and calcite get their maximum of 97.64%, 91.04% and 95.99%, respectively. The flotation recoveries of quartz, calamine and calcite rise sharply with the rise of pH. And in a wide range of pH, their flotation recoveries all exceed 90%. And in the whole flotation experiment, the flotation recovery of hematite rises with the increase of collector concentration and pH, while the maximal recovery is not more than 55%. Compared with dodecylamine, the N-dodecylethylenediamine has strong capability to quartz and calamine, while the flotation recoveries of calcite are closely. Hydrogen binding adsorption and electrostatic adsorption occur between the collector and the surface of quartz.     

直链烷基胺浮选铝硅矿物机理

研究了一水硬铝石和高岭石、叶蜡石及伊利石等几种含铝硅酸盐矿物在不同pH条件下的动电行为与浮选行为。一水硬铝石、高岭石、叶蜡石及伊利石的等电点（IEP）分别为pH6．2,4．3,2．0,3．4。在pH＞IEP时,烷基胺类阳离子捕收剂主要以静电作用吸附在一水硬铝石矿物表面,其浮选高岭石等3种铝硅酸盐矿物的可浮性大小顺序是叶蜡石＞高岭石＞伊利石。高岭石、叶蜡石和伊利石均是层状硅酸盐矿物,其破碎磨细时,将沿层间断裂,由于晶体结构的原因其层面荷负电荷。烷基胺类阳离子捕收剂以静电作用力吸附于铝硅酸盐矿物表面的层面使矿物疏水上浮。     

Flotation behavior and mechanism of rutile with nonyl hydroxamic acid

The flotation and surface interaction of rutile with nonyl hydroxamic acid were investigated in this work. The results show that the adsorption density and flotation recovery of rutile have similar tendency, especially the maximum recovery and adsorption occur at pH about 7.5. In terms of Fourier transform infrared (FTIR) spectroscopic analysis, chemical adsorption is identified on the surface of rutile, where a chelate of O,O-five-membered rings with Ti⁴⁺ on the surface of rutile may form. Adsorption measurements, Zeta potential test, IR spectrum analyses, and solution chemistry calculations illustrate that the adsorption on the rutile surface involves both physical and chemical adsorption, while chemical adsorption is dominant.