浮选药剂的亲固能计算

在浮选体系下，药剂和矿物的作用不仅和键合原子有关，还和矿物表面相邻原子、药剂亲固基团以及介质水分子有关。在此模型下提出了药剂亲固基团和矿物表面作用能的计算公式，利用这一公式可定量研究矿物表面极性、药剂分子极性和介质水分子对浮选药剂亲固能的影响。研究结果表明，浮选介质分子水影响药剂和矿物表面作用能的强弱，对于极性较小的矿物（如硫化矿物），其表面和药剂亲固基团的作用能与基团电负性成反比，基团电负性越小，作用越强；对于极性较大的矿物（如非金属矿物），其表面和药剂亲固基团的作用与基团电负性成正比，基团电负性越大，作用越强。     

新型捕收剂N—十二烷基—1，3—丙二胺浮选铝硅酸盐类矿物的机理

以十二胺和丙烯腈为原料,常压下合成了阳离子捕收剂N-十二烷基-1,3-丙二胺(DN12),考察了其对高岭石、叶蜡石、伊利石的浮选行为.结果表明DN12的捕收性能优于十二胺;DN12的浓度为3×10-4mol@L-1时,对3种铝硅酸盐矿物的浮选回收率均超过80%,对3种铝硅酸盐矿物的捕收能力顺序为高岭石＞叶蜡石＞伊利石;浮选pH范围为5～8.动电位和红外光谱说明DN12与铝硅酸盐类矿物形成了氢键并产生静电吸附,且作用较强.     

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。     

Gemini双季铵盐捕收剂BDDA和EDDA对高岭石、叶腊石、伊利石浮选行为的比较及机理

采用了新型Gemini双季铵盐捕收剂丁烷-1,4-双十二烷基二甲基溴化铵（BDDA）和乙烷-1,2-双十二烷基二甲基溴化铵（EDDA）对比研究了其对高岭石、叶腊石、伊利石的浮选行为及作用机理。单矿物试验结果表明,在广泛的pH范围内,新型Gemini双季铵盐捕收剂BDDA和EDDA对三种铝硅酸盐矿物具有优异的捕收性能,且BDDA的捕收能力强于EDDA。红外光谱和动电位研究表明,Gemini双季铵盐捕收剂对三种铝硅酸盐矿物的作用机理为静电吸附和氢键作用。采用DFT密度泛函理论,在B3LYP／6—31G（d）水平上对捕收剂阳离子BDDA2＋和EDDA2＋进行量化计算,结果表明BDDA的捕收能力强于EDDA。这与单矿物浮选结果、动电位测定结果一致。     

辛基胍浮选铝硅酸盐矿物的研究

以辛基硫酸胍SAG8为捕收剂,通过浮选实验、Zeta电位和红外光谱测定,研究了SAG8对铝硅酸盐矿物的浮选性能和作用机理.结果表明:在pH为4-12的范围内SAG8对高峰石、叶腊石和伊利石这三种铝硅酸盐都有较好的捕收能力.Zeta电位测得高峰石、伊利石和叶蜡石的等电点分别为3.5、3.0和2.3.矿物与SAG8作用后其表面正电荷密度增加的均不明显.其可能的原因是:胍是有机强碱.当胍分子一个NH2+与矿物表面Si-O-通过静电作用吸附于矿物表面后,由于胍基中还存在一个NH2官能团,它与矿浆中或者矿物表面的OH-发生氢键作用,矿浆表面OH-浓度增加,从而使矿物表面正电荷密度增加不明显矿粒表面荷负电.结合浮选实验、Zeta电位和红外光谱可以推断出矿物与SAG8的作用机理:SAG8阳离子中同时存在阳离子型和分子型两种NH2官能团,使得SAG8阳离子以静电力和氢键两种方式吸附铝硅酸盐矿物表面.其中在酸性介质中,SAG8主要通过静电力方式吸附在铝硅酸盐矿粒表面,而在碱性条件下以静电力和氢键两种方式作用.     

阴阳离子混合捕收剂对异极矿的浮选作用及机理

采用DDA(十二胺)和KAX(异戊基黄原酸钾)的阳阴离子混合药剂作为捕收剂,对异极矿进行单矿物浮选及检测,并与单独使用DDA或者KAX作为捕收剂进行比较。结果表明:采用DDA和KAX的摩尔比为1:3的混合捕收剂浮选异极矿时,比单独使用DDA或者KAX对异极矿的浮选效果要好,且在pH值为10左右时浮选效果最佳,回收率达86%;DDA和KAX混合后各自所带的阴、阳离子电性中和,降低了捕收剂分子之间的静电斥力,从而使混合捕收剂的临界胶束浓度值降低,在矿物表面吸附时形成半胶束吸附的浓度值降低,更易于在异极矿表面形成半胶束吸附,对矿物浮选捕收效果增强。     

异极矿成矿规律及浮选药剂作用机理研究现状

本文主要考察了异极矿的成矿规律、结构特征以及异极矿与浮选药剂之间的作用规律,详细分析了影响异极矿可浮性的重要因素,总结了国内外与异极矿相关的浮选药剂与异极矿之间的作用规律,研究结果表明:在成矿的前期阶段,异极矿易与粘土矿物混杂,采用浮选法进行回收时含锌矿物易损失于矿泥中,从而使得异极矿的浮选回收率较低;胺类捕收剂的极性基团—NH_2中N、H原子与异极矿表面的Zn、Si、O、H等原子之间并未形成有效的化学键,捕收剂与异极矿之间的作用方式仅为静电吸附;由于异极矿中SiO_4~-的体积比Zn~(2+)更大,在与浮选药剂发生作用时,矿物表面的Zn~(2+)往往被SiO_4~(2-)屏蔽,使得矿物溶解度降低,从而使得S~(2-)、HS~-等起硫化作用的离子很难与Zn~(2+)结合,硫化时间增长;螯合剂法有望成为异极矿浮选新的高效选别方法。     

油酸在石英与长石表面的吸附

通过动电电位测定、吸附量测定、红外光谱分析及单矿物浮选等手段，研究了油酸在石英和长石表面的存在状态及吸附作用。结果表明，油酸以两种方式吸附：油酸根离子的静电吸附和油酸分子的物理吸附，在长石表面还存在油酸根离子与铝离子之间的化学吸附，因此，油酸在长石表面的吸附强度高于石英，试验还表明，在抑制剂的配合下，油酸钠可以活化阳离子胺类捕收剂对长石的捕收。     

变性淀粉在铝硅矿物浮选分离中的作用机理

通过浮选实验、动电位和红外光谱测定,详细考察了变性淀粉在铝硅矿物浮选分离中的作用效果和机理。浮选实验显示：非离子淀粉和阴离子淀粉在pH＜6时,抑制一水硬铝石的浮选,但当pH＞6时,却对一水硬铝石浮选有活化作用;阳离子淀粉在较宽pH值范围内对一水硬铝石均有抑制作用;3种淀粉化合物在pH＜6时均活化高岭石的浮选,当pH＞6时活化作用较微。结果表明：变性淀粉是一水硬铝石型铝土矿反浮选中实现一水硬铝石和高岭石分离的有效调整剂,阴离子淀粉使矿物表面ζ电位更负,阳离子淀粉使矿物质表面ζ电位更正,非离子淀粉使矿物表面电位绝对值减小。由实验结果结合药剂与矿物作用前后的红外光谱分析,得出结论：非离子淀粉主要通过氢键作用吸附于矿物表面,而静电力和化学键合力在阴离子淀粉和阳离子淀粉吸附中发挥着重要作用。     

钨钼分离吸附剂的选择性判据

借鉴浮选药剂与矿物作用的亲固能计算方法,得到钨钼分离体系吸附剂与被吸附基团的吸附能计算公式。基于逐级均分法计算出钨钼分离过程中主要原子团的基团电负性,发现钼原子团(??24SMo Oxx)的基团电负性随着x的增加而减小,其与钨氧原子团(2?4WO)的电负性差异也逐渐增大。通过吸附能计算公式得到钨钼原子团在不同吸附剂上的吸附能,表明吸附剂极性越低,其对四硫代钼酸根的吸附能力越强。从而预测系列化合物对钼硫原子团选择性吸附的强弱,并被选择性沉淀法及实验室实验印证。本研究中吸附剂的分子设计思路有望为新型钨钼分离试剂的开发设计提供理论指导。     

Flotation of aluminosilicate minerals using alkylguanidine collectors

The flotation mechanism of aluminosilicate minerals using alkylguanidine collectors was studied through flotation experiments, Zeta potential measurements and FT-IR spectrum analysis. It is shown that kaolinite, illite and pyrophyllite all exhibit good floatability with alkylguanidines as collectors at pH 4-12. The flotation recoveries rise with the increase of the carbon chain length. Isoelectric point(IEP) is determined to be 3.5, 3.0 and 2.3 for kaolinite, illite and pyrophyllite, respectively. However, it is anomalous that the presence of cationic collectors has less influence on the negatively charged mineral surfaces. It is explained by the special structure of guanidine which is one of the strongest bases, having two -NH2 groups. One of them maybe interacts with minerals by electrostatic forces, and the other maybe forms hydrogen bonding with OH- ions on the aluminosilicate surfaces or in the aqueous solution, increasing the density of negative charge on the aluminosilicate surface and leading unpronounced positive charge to increase on the aluminosilicate. By combining the flotation tests, Zeta potential and FTIR measurements above, the interaction mechanism can be concluded. The simultaneous presence of cationic and neutral amine groups makes it possible for SAG cation to bind on three aluminosilicate minerals by both electrostatic attraction and hydrogen bonding. While in acidic medium, the interaction of the alkylguanidines on the aluminosilicate surfaces is mainly by means of electrostatic force and hydrogen bond; in the alkaline medium, it is by the way of electrostatic effect and hydrogen bond.     

Calculation of topological connectivity index for minerals

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Synthesis of N-decyl-1,3-diaminopropanes and its flotation propertieson aluminium silicate minerals

1　INTRODUCTIONBauxiteisamajorsourceforaluminaproduction .Bayerprocessfeaturesshortresidencetime ,lowener gyconsumptionandhigh qualityproduct .Asare sult ,itiswidelyusedtotreatthebauxiteofalu minum/silicateratio (A/S)morethan 8.AlthoughthereareabundantaluminiumoxidemineralresourcesinChina ,mostofthemarediasporicbauxitewithhighaluminumcontent ,butlowA/Sratio .Among4 0bauxitediggings ,theaverageAl2 O3andSiO2 con tentsare 6 3.4 1%and 11.5 9% ,respectively ,whiletheaverageA/Sratiois4 6 […     

苯二氧基二乙酸的相转移催化合成及其浮选性能

用三丁基乙基硫酸乙酯铵作相转移催化剂，以苯二酚、一氯乙酸和氢氧化钠为原料，用三氯甲烷作溶剂，合成了3种不同结构的苯二氧基二乙酸。分别以油酸钠、十二胺和丁黄药为浮选捕收剂，考察了苯二氧基二乙酸对方解石、一水硬铝石和黄铁矿的抑制性能。结果表明，苯二氧基二乙酸的抑制能力较强，对上述3种矿物的抑制性能大小顺序为：方解石＞一水硬铝石＞黄铁矿，可作为方解石等含钙、镁脉石矿物的有效抑制剂。从基团电负性、浮选剂特性指数和亲憎平衡值等方面，对苯二氧基二乙酸的抑制性能进行了讨论。用MINDO3方法对3种药剂进行了量化计算，量化计算结果表明，它们的抑制能力大小顺序为：对位＞间位＞邻位；它们均以负一价离子的形式与矿物中的金属离子发生作用，未离解的羧基则难以发生离解，从而保证药剂与矿物作用后的亲水性，使矿物得到抑制。     

Structure–activity relationship and mechanisms of reagents used in scheelite flotation

Effects of carboxylic acid collector,benzohydroxamic acid(BHA),sodium hexametaphosphate(SHAP),sodium silicate,and oxalic acid on scheelite flotation were studied through flotation tests,quantum chemical calculation,and flotation solution computational chemistry.In terms of the calculation results,the relationship between chemical reactions occurring on the scheelite surface and molecular structures of the reagents were analyzed.The results show that BHA and carboxylic acid collectors interact with scheelite in different forms and the recovery of scheelite using sodium oleate as collector declines successively from SHAP,sodium silicate,to oxalic acid.Moreover,it is found that the performance of depressant in scheelite flotation is directly related to the group electronegativity,indicating that the latter is a dominant factor that determines the former.These findings will be helpful to the academic research communities of scheelite flotation.     

Molecular structures and activity of organic depressants for marmatite, jamesonite and pyrite flotation

Ten kinds of organic depressants were used to investigate the depressing performance on marmatite and pyrite.Flotation results show that the organic compounds only with single group of hydroxyl(-OH),carboxyl(-COOH) or amino(-NH2) in molecule are ineffective in depressing marmatite,jamesonite and pyrite.The combinations of these functional groups still cannot enhance the depressing ability of organic depressant.The thioglycollic acid containing reductive functional group(-SH) has a good depressing performance for marmatite and pyrite.The presence of benzene ring in molecule can enhance the depressing performance.The functional group electronegativity,hydrophilic-hydrophobic indexes and frontier orbital of organic depressants were calculated,and the criterion for the depressing effect of organic depressants to sulphide minerals was proposed.     

再论固体渗碳剂中碳酸盐的催化机理

本文评论了文献中广为引用的氧迁移催化机理（ＯＴＴ）是难以令人相信的；其次详述了“电子循环接受催化理论”（ＥＣＤＡＴ）。这个理论认为：催化剂的催化作用是电子迁移形式。加入的催化剂有利于被扭曲的碳分子轨道恢复到原始的对称平衡状态，从而加速ＣＯ气体的生成。催化剂的催化活性大小取决于加入催化剂的电负性大小。凡是比碳电负性小的元素或化合物均具有催化活性；电负性越小，催化活性越大。反之，凡是比碳电钢性大的元素     

Physicochemical and adsorption-structural properties of diatomite modified with aluminum compounds

A selective sorbent based on the diatomite of local origin modified with aluminum compounds has been studied by the methods of powder X-ray diffraction; FTIR; and differential thermal, adsorption-structural (BET), and chemical analyses. The surface modification of diatomite is carried out by heating it in an NaOH solution and its subsequent treatment with a solution of aluminum salt and ammonia. The amorphous surface silica partially dissolves during the treatment with NaOH and forms an aluminosilicate compound at the addition of an aluminum salt. The obtained material is deposited both on the surface of the diatomite and on the inner surface of the macro- and larger mesopores, which leads to the development of the specific surface area of 81.8 m²/g, which is 2.5 times larger than the corresponding value in the initial diatomite (37.5 m²/g). The precipitated aluminosilicate compound with the concentration equal to 0.34 g of Al/g of aluminosilicate contributes to the development of a porous structure in the treated diatomite, so the volume of the mesopores increases from 0.029 to 0.079 cm³/g and that of the micropores from 0.012 to 0.027 cm³/g. The qualitative changes in the composition of the obtained sorbent are confirmed by the emergence of new lines in the X-ray diffraction patterns, which are characteristic for aluminosilicates, and additional peaks in the infrared spectra corresponding to the stretching vibrations of Si-O-Al. The selectivity of the obtained adsorbent with respect to fluoride ions increases significantly, specifically, its adsorption capacity increases from 8.9 to 57.6 mg of F/g at the initial fluorine concentration equal to 0.15 mol/L.     

Schiff-base derivatives as corrosion inhibitors for carbon steel materials in acid media: quantum chemical calculations

Quantum chemical calculations based on Hartree–Fock, AM1 and B3LYP functions were performed on the three Schiff-base compounds used as corrosion inhibitors for carbon steels in acid media. The quantum chemical calculations were conducted to determine the relationship between inhibition efficiency (IE) and the molecular structure of inhibitors. Several quantum chemical parameters, such as charge distribution, energy and distribution of the highest occupied molecular orbital (E_HOMO) and lowest unoccupied molecular orbital (E_LUMO), absolute electronegativity (χ) and the fraction of electrons (ΔN) transferred from inhibitors to the steel surface, were calculated and correlated with inhibition efficiencies. The results showed that the IE of Schiff-base compounds enhanced with increasing E_HOMO or decreasing E_LUMO; meanwhile, N atoms on Schiff-base molecules were the most probable sites for adsorption of inhibitor molecules on the metal surface. The inhibition mechanisms of three Schiff-base compounds were obtained from different calculation methods, and the results from each method are consistent.     

Novel thiophene symmetrical Schiff base compounds as corrosion inhibitor for mild steel in acidic media

The inhibiting effect of two Schiff bases on the corrosion of the mild steel (MS) in 1 M HCl has been studied by electrochemical impedance spectroscopy (EIS) and Tafel polarisation measurements. The Schiff bases, 4,4′-bis(3-carboxaldehyde thiophene) diphenyl diimino ether (L₁) and 4,4′-bis(3-carboxaldehyde thiophene) diphenyl diimino ethane (L₂), were synthesized using 3-carboxaldehydethiophene and its corresponding amine. Polarisation curves reveal that both compounds are mixed type (cathodic/anodic) inhibitors and inhibition efficiency (% IE) increases with increasing concentration of compounds. It is suggested that their effects depend on their concentrations and the molecular structures. Adsorption of compounds on mild steel surface is spontaneous and obeys Langmuir’s isotherm.