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。     

一水硬铝石型铝土矿铝硅浮选分离的溶液化学

分析了我国铝土矿中一水硬铝石和铝硅酸盐脉石矿物的晶体结构与表面性质,一水硬铝石与铝硅酸盐脉石矿物晶体结构的差异、表面断裂的Al-O和Si-O健及表面离子活性区的差别,可影响矿物表面的润滑性与可浮性,类质同象及各种晶格杂质离子也将影响浮选剂与矿物表面的相互作用和矿物可磨性,提出了正浮选、反浮吕硅分离的技术原型,用溶液化学与计算研究了其基本原理。结果表明,通过溶液化学计算可确定阴离子捕收剂正浮选脱硅时捕收剂,分散剂和PH三者之间的匹配关系,矿物的PZC与捕收剂的pKa值是阳离子捕收剂反浮选的主要控制参数,阴离子捕收剂反浮选时,铅盐和钙盐是浮选铝硅酸盐较理想的活化剂。     

铝土矿反浮选体系分散与凝聚理论

在铝土矿反浮选脱硅过程中,矿浆悬浮液的分散和凝聚状态对微细粒－水硬铝石的回收和精矿铝硅比有显著影响。要使各种硅酸盐矿物混合物达到有效的选择性分离,首先必需使矿浆悬浮液处于最佳分散状态,避免各种矿物细粒间的相互混杂和矿泥罩盖。针对高硅铝土矿反浮选脱硅过程,根据经典DLVO理论,从颗粒间的相互作用分析了微细粒－水硬铝石在各种含硅脉石矿物表面的粘附情况。结果表明：一水硬铝石与含硅脉石矿物颗粒间的范德化相互作用总是吸引;而它们间的静电相互作用在弱碱性条件下时为排斥,在弱酸性条件下时为吸引,一水硬铝石的夹带上浮较为严重,不利于铝土矿的反浮选。     

捕收剂的分子设计与绿色合成

捕收剂是矿物浮选分离过程中必不可少的药剂,研究捕收剂的分子设计与绿色合成对于提高浮选技术水平具有重要意义。综述近年来中南大学钟宏教授课题组在捕收剂的分子设计、绿色合成与浮选机理研究方面的系列成果。研究开发溶剂法合成黄原酸盐等硫化矿捕收剂的绿色合成技术,提高合成效率,改善生产环境。设计并合成异丁基黄原酸苯甲酰基酯等多种新型硫化矿捕收剂、Gemini双季铵盐等多种新型非硫化矿捕收剂及N,N-二丁基二硫代氨基甲酸乙羟肟酸等硫化?氧化矿双功能捕收剂,此外还研究选矿药剂之间的组合用药。     

Aluminum-silicates flotation with quaternary ammonium salts

1　INTRODUCTIONThediasporic bauxiteinChinaisdifferentfromthegibbsite bauxiteandboehmite bauxiteinothercountriesbyitshighcontentofAl2 O3andSiO2 andlowmassratioofAl2 O3toSiO2 (massratioofAl2 O3toSiO2 =A/S ,usually5 6 ) .Theproductioncostofa luminumoxidefromsuchrefractorybauxiteby“sin tering”or“combining”technologiesismuchhigherthanthatbyBayer sprocess .Sothatthealuminum silicateganguessuchaspyrophyllite ,illiteandkaolin iteinthebauxiteisneededtoberemovedtoincreaseA/S .Hussainetal…     

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.     

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。     

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。     

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.     

Comparative studies on flotation of illite, pyrophyllite and kaolinite with Gemini and conventional cationic surfactants

To search a novel class of effective silicate mineral collectors, the Gemini quaternary ammonium salt surfactant (butane-α, ω-bis(dimethyl dodeculammonium bromide), 12-4-12) and its corresponding conventional monomeric surfactant (dedecyl trimethyl ammonium bromide, DTAB) were adopted to comparatively study the flotation behaviors of illite, pyrophyllite and kaolinite. Three silicate minerals with the Gemini surfactant as collector reveal floatability far better than with the corresponding traditional one. At pH 6, the best recoveries of illite, pyrophyllite and kaolinite with 3.5×10-4 mol/L 12-4-12 are 99.2%, 91.7% and 99.6%, respectively. The fluorescence and contact angle measurement were also conducted for the further investigation of surfactants aggregation behavior and silicate mineral surface hydrophobic properties. FTIR spectra analysis and electrokinetic analysis show that the mechanism of adsorption of collector molecules on mineral surfaces is almost identical for the electronic attraction and hydrogen bonds effect. The superior collecting power of dimeric collector may be attributed primarily to its special structure and its essential properties.     

Sulphidization flotation for recovery of lead and zinc from oxide-sulfide ores

A new flowsheet was developed to recover the valuable minerals from oxide or oxide-sulfide ores of lead and zinc. The flowsheet consisted of flotation of sulfide minerals, desliming and sulphidization-flotation of oxide minerals. The corresponding reagent system and techniques to the flowsheet were investigated. Batch and continuous tests show that the dosage of sodium sulfide, temperature, and collector type are main affecting factors on the recovery of smithsonite and cerussite. For the flotation of cerussite, there is an appropriate dosage of sodium sulfide at which the recovery reaches its maximum value. The required sodium sulfide for smithsonite flotation is higher than that for cerussite and the recovery of smithsonite flotation increases with the dosage of sodium sulfide at low level and becomes insensitive at high dosage. The appropriate temperature for smithsonite and cerussite flotation is found to be 25 ～ 40℃. Amines are found to be the effective collectors for the flotation of smithsonite after sulphidization. Investigation also shows that desliming prior to sulphidization-flotation is essential to the effective recovery of smithsonite and cerussite, and the desliming process of two-stage hydrocyclon is well feasible and effective for the treatment of lead-zinc oxide ores. A further treatment on the cerussite flotation concentrate by shaking table is proposed to obtain higher lead grade.     

Recent advances in electrochemistry of sulfide mineral flotation

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新型捕收剂作用下赤铁矿与胶磷矿的分选及机理(英文)

对新研制的反浮选降磷捕收剂(RFP138)体系中赤铁矿和胶磷矿的可选性及作用机理进行研究。赤铁矿和胶磷矿的单矿物及人工混合矿的反浮选分离试验表明:RFP138是赤铁矿和胶磷矿的良好捕收剂,在碱性条件下采用合适的抑制剂,能够有效地实现两种矿物的分选,将P含量由人工混合矿中的1.05%降至0.12%,且TFe的回收率达到91.30%。对RFP138溶液的化学行为及红外光谱进行分析,探讨RFP138对两种矿物选择性捕收的机理。     

两种层状镁硅酸盐矿物的晶体结构与可浮性研究

通过对两种层状镁硅酸盐矿物—蛇纹石和滑石的浮选实验及润湿接触角的测定,研究了蛇纹石与滑石的晶体结构与表面润湿性、可浮性的关系,结果表明:蛇纹石的润湿性较好,可浮性差;滑石的润湿性较差,可浮性好。     

First-principle investigation on mechanism of Ca ion activating flotation of spodumene

Different hypotheses of the activation mechanisms of metallic ions for silicate minerals flotation were stated in this work. Spodumene and Ca ion were taken to illustrate this issue. Flotation test results and diagram of Ca ion species distribution vs pH show that the dominant hydrolyzed species are Ca（OH）？and Ca（OH）2, which is in correspondence with the maximum flotation recovery of spodumene. Density functional theory（DFT） calculation results reveal further that the precipitation of calcium hydroxide on spodumene surface is the effective process to activate the flotation of spodumene.     

Influence of metal cations on cassiterite flotation

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Flotation techniques for separation of diaspore from bauxite using Gemini collector and starch depressant

The floatability of diaspore and three kinds of silicate minerals,including kaolinite,illite and pyrophyllite,by a cationic Gemini surfactant as collector and starch as depressant was investigated as function of reagents concentration and pulp pH.Further studies of artificially mixed minerals and bauxite ore were also detailedly conducted.At last,the pre-desliming reverse flotation separation process was adopted.It can be concluded that the combinational use of a Gemini cationic collector and the starch dep...     

Selective flotation of smithsonite,quartz and calcite using alkyl diamine ether as collector

The flotation separation of smithsonite from calcite and quartz using a alkyl diamine ether (GE-609) as the collector was investigated through micro-flotation experiments and the real ore flotation experiments. The results show that GE-609 exhibits good collecting capability to three minerals without selectivity. The presence of sodium sulfide enhances the flotation of smithsonite and calcite while inhibits quartz. Moreover, both sodium silicate and sodium hexametaphosphate exhibit good selective inhibition to calcite. The real ore test results show that a zinc concentrate containing 23.51% Zn with the recovery of 71.02% is obtained in the closed-circuit test. To understand the adsorption of GE-609 on smithsonite surface, zeta potential measurement and FTIR analysis were carried out, and the results indicate that the collector GE-609 can adsorb on smithsonite surface through both electrostatic adsorption and chemical adsorption, and the presence of sodium sulfide enhances the adsorption of GE-609.     

胺类捕收剂的结构与性能研究

研究了脂肪伯胺、叔胺、多胺和醚胺四种药剂对高岭石、叶腊石、伊利石的浮选行为，结果表明捕收能力顺序为多胺＞叔胺＞醚胺＞脂肪＞伯胺。量化计算结果说明这两种胺类化合物易阳离子化，N数越多，N上烃基越多，药剂的阳离子化趋势越强。动电行为表明胺类化合物在铝硅酸盐矿物表面发生了静电吸附，当药剂极性基团电负性越大，改变矿物表面电性也越大。基团电负性、浮选剂特性指数、水油平衡度和疏水链长的计算表明捕收剂对铝硅酸盐类矿物捕收的决定因素是极性基的特性。     

Floc flotation of marmatite fines in aqueous suspensions induced by butyl xanthate and ammonium dibutyl dithiophosphate

The hydrophobic flocculation of marmatite fines in aqueous suspensions induced by butyl xanthate (KBX) and ammonium dibutyl dithiophosphate (ADD) was investigated using laser particle size analysis, microscopy analysis, electrophoretic light scattering, contact angle measurement and infrared spectroscopy. The studies were performed on single minerals with size ≤20 µm by varying several parameters, including pH, collector concentration and kerosene addition. The results show that the floc flotation closely correlated with the size of flocs and the particle hydrophobicity, but was not lowered with increasing the particle surface charges due to collector adsorption. Under good operating conditions, the floc flotation of marmatite fines as a function of KBX and ADD can all reach floatability over 90%, in comparison with conventional flotation obtaining floatability of about 60%. It also has been found that a small addition of kerosene greatly improved the floc flotation because of the formation of oil films on marmatite particles. The results of FTIR spectra indicate that adsorption of the two collectors onto marmatite were chemical adsorption.