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…     

纳米Al2O3-Fe3O4/FeS固体润滑复合层减摩润滑机理

采用离子氮碳共渗与离子渗硫复合处理技术在45钢表面形成FeS固体润滑复合层,然后采用真空浸渍方法将纳米Al2O3和Fe3O4颗粒置入复合层的微纳孔隙中,制备成纳米Al2O3-Fe3O4/FeS固体润滑复合层.在10 ～60 N的载荷下,纳米Al2O3-Fe3O4/FeS固体润滑复合层表现出优良的减摩与耐磨性能.这是因为,一方面磨损表面生成的化学反应膜,起到了固体润滑和阻碍摩擦表面间金属直接接触的作用;另一方面在摩擦过程中,纳米Al2O3-Fe3O4/FeS固体润滑复合层中的纳米Al2O3和Fe3O4颗粒起到了“微纳滚珠”作用,微观上将“滑动摩擦”部分转变为“滚动摩擦”,且纳米颗粒预先置入复合膜层中,在摩擦过程中不易流失,延长了其“微纳滚珠”的作用,从而使其摩擦因数(载荷60 N时)及体积磨损量比涂抹纳米Al2O3/Fe3O4复合添加剂润滑的FeS固体润滑复合层分别降低了7.2％和50％.     

Synthesis and electrochemical properties of nanocrystalline Li[Li1／3Ti5／3O4] by complex sol-gel method

1　INTRODUCTIONSpinelLi[Li1/3Ti5/3O4 ]isaveryattractiveelec trodematerialforitsexcellentcyclelifeandpromisingchargingrateinrechargeableenergystoragecells .Duringelectrochemicalreactionsconsistingofelectronandlithiumioninsertionintoorextractionfromit,itslatticeconstantchangesveryslightly ,soitiscon sidereda“zero strain”insertioncompound[13] .Thismaterialwassuccessfullyusedasanodecoupledwithhighpotentialcathodematerials (LiMn2 O4 ,LiCoO2oractivecarbonfiber)toprovideacellorhybridsu perc…     

β-NiAl涂层及其加入稀土后的氧化膜表面形貌与生长机制

分别用金属镍“扩散渗铝+离子注Y”与“Ni-La2O3共沉积+扩散渗铝”方法制备了Y和La2O3改性的β-NiAl涂层,与单纯的金属镍上的渗铝涂层相比,两种掺有稀土(RE)的β-NiAl涂层的氧化速率降低.SEM的观察显示,1000℃恒温氧化24h后,不含RE的涂层表面氧化膜已局部剥落,而含RE的涂层表面氧化膜不发生剥落,3种涂层的氧化层表面皆出现“晶须”或“刀片”状的氧化物.对含Y涂层在氧化初期的不同阶段的表面进行SEM观测,发现其上生长的氧化产物的形貌有明显的规律性变化.HREM的结果显示,含La2O     

从失效载体催化剂回收铂的工艺研究

用硫酸溶解γ-Al2O3-焚烧脱炭-“消化”转溶α-Al2O3-铂精矿精炼铂的火湿法冶金工艺处理复杂成份失效载体催化剂效果好,铂产品纯度＞99.5%,回收率＞97.5%.     

熟料烧结过程中氧化铁反应行为的热力学分析

通过对Fe2O3与碳酸钠、氧化钙以及硅酸钙反应的热力学分析,明确Fe2O3在铝土矿炉料烧结过程中的热力学反应规律。热力学计算、分析结果表明:Fe2O3在正常烧结温度范围内能与Na2CO3或CaO发生反应,但更易与CaO反应形成2CaO.Fe2O3或CaO.Fe2O3,Fe2O3和Na2O.Fe2O3能使2CaO.SiO2和3CaO.2SiO2转变为CaO.SiO2,CaO.SiO2进一步与Na2O.Al2O3或Na2O.Fe2O3反应生成不溶的三元化合物而造成烧结法生产氧化铝过程中Na2O和Al2O3的损失。4CaO.Al2O3.Fe2O3不能由铁酸钙和铝酸钠相互反应产生,而可能是CaO、Al2O3和Fe2O3三者直接反应的产物,且在烧结条件下Na2O.Fe2O3可分解4CaO.Al2O3.Fe2O3。     

Na2O含量对BaO-SrO-Nb2O5-B2O3-SiO2系玻璃陶瓷微结构和性能的影响

采用熔融法制备NaO-BaO-SrO-Nb2Os-B2O3-SiO2玻璃陶瓷.借助DSC、XRD、SEM和电学性能测试研究不同含量的Na2O对其相组成、显微结构、介电性能、体积电阻率及击穿强度的影响.结果表明随着Na2O含量(摩尔分数)的增加,玻璃转变温度(Tg)和第一析晶放热峰(Tg1)温度逐渐降低,而第二析晶放热峰温度(Tg2)呈先降低后升高再降低的变化.经(800℃,3h)+(900℃,3h)热处理后,未添加Na2O的样品析出单相四方钨青铜结构的Ba0.5Sr0.5Nb2O6,而添加5%Na2O(摩尔分数)的样品变为单相Ba0.25Sr0.75Nb2O6.当Na2O为10%时,样品的主晶相仍为Ba0.25Sr0.75Nb2O6,但析出NaSr1.2Ba0.8Nb5O15和Na2Ba2Si2O7相;继续增加Na2O量到15%时,样品的晶相种类不变而衍射峰强度有所增强.样品的介电常数随Na2O含量的增加呈“N”字形变化,样品的体积电阻率和击穿强度随Na2O含量的增加而降低,未添加Na2O试样的击穿强度最大为1500kWcm,其储能密度达3J/cm3.     

Preparation of Al2-xYxW3O12 powders by citrate sol-gel process

Al2-xYxW3O12 （x=0.2, 0.5, 0.8, 1.0, 1.2, 1.5, 1.7 and 2.0） powders were synthesized by citrate sol-gel process. The concentration of species in a citric solution for preparing Al2-xYxW3O12 powders was calculated. The powders were characterized by differential thermal analysis（DTA）, thermogravimetry（TG）, X-ray diffractometry（XRD） and scanning electron microscopy（SEM）, respectively. No solid solution of Al2-xYxW3O12 is formed with x values varying from 0 to 2.0. The maximum solid solubility of Y2O3 in Al2W3O12 and Al2O3 in Y2W3O12 is less than 0.5. Y2W3O12 easily absorbs water in air and forms a composition of Y2W3O12·3.2H2O, and Al2W3O12 forms Al2W3O12·0.17H2O in the same condition.     

Nature of (001) and (00) faces and flocculation flotation of kaolinite

1　INTRODUCTIONThediasporicbauxiteresourceinChinaischar acterizedbyhighcontentofAl2 O3andSiO2 andlowmassratioofAl2 O3toSiO2 ,theratioisusually 5 8.ThediasporicbauxitewithlowmassratioofAl2 O3toSiO2 cannotbedirectlyprocessedbyBayer’stechnol ogy .ThesinteringorcombinationofsinteringandBayerprocessareoftenusedtotreatsuchdiasporicbauxite ,showingenergy intensiveandenvironmentalunfriendly[1] .ItisrequiredtoincreasethemassratioofAl2 O3toSiO2 toabove 10byphysicalseparationsothattheBayer…     

煤粉燃烧法附产氧化铝熟料的反应过程分析

利用XRD和三元相图分析对煤粉燃烧法附产氧化铝熟料的形成过程进行了研究,初步分析了煤粉燃烧法附产氧化铝熟料的矿物组成及反应过程。结果表明:在高铝煤粉和石灰燃烧过程中,首先是CaO与Al2O3和SiO2反应生成CaO.Al2O3及2CaO.SiO2,随后CaO.Al2O3与2CaO.SiO2反应生成2CaO.Al2O3.SiO2,1000℃燃烧时已经大量生成低碱性矿物2CaO.Al2O3.SiO2。随着燃烧温度的升高,CaO.Al2O3和CaSO4直接反应生成3CaO.3Al2O3.CaSO4。     

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。     

异丁黄药用于高硫铝土矿浮选除硫的研究

鉴于我国铝土矿保有量有限,高品位铝土矿由于掠夺性开采而面临枯竭,具有高品位的高硫铝土矿将是今后氧化铝生产的主要矿物原料。而高硫铝土矿脱硫,是该类型铝土矿能否工业应用的关键。本试验采用单因素实验,研究了高硫铝土矿在浮选剂异丁黄药作为捕搜剂,松油醇为起泡剂进行高硫铝土矿反浮选除硫的工艺条件。重点考察了浮选剂用量、浮选时间、浮选矿浆浓度、pH值及矿石粒度对浮选的影响,得出了反浮选除硫的适宜工艺条件。研究表明,在适宜工艺条件下,异丁黄药浮选除硫后的尾矿中,硫含量由原矿2.08%达到15.1%,精矿中硫含量降为0.62%,达到工业生产氧化铝的要求(0.7%)。氧化铝回收率为92.3%。在弱碱性条件下,异丁黄药的捕搜性能在硫酸铜活化下有很大提高。浮选动力学研究表明,异丁黄药对硫化矿的浮选符合Langmuir的化学吸附原理。     

Intensifying digestion of diaspore and separation of alumina and silica

1　INTRODUCTIONDespitetheabundantdepositofbauxitesinChi na ,ofthosepredominantisthediasporictypewithhighalumina ,highsilicaandlowferricoxides .Thebauxitedeposit,withthemassratioofaluminatosil ica(A/S)between 4and 8,accountsfor 80 %ofallthebauxitedeposit.Thenatureofhighsilicacontentdeterminesthatthemainlyadoptedtechniquetopro ducealuminainChinashouldbeBayer sinteringcom binationprocessorevenpuresinteringprocess .Althoughadramaticadvancementinaluminaproductionhasbeenachievedandthetechnolo…     

Optimization of grinding in reverse flotation for bauxite

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｂａｕｘｉｔｅｉｓｔｈｅｉｍｐｏｒｔａｎｔｍａｔｅｒｉａｌｆｏｒａｌｕ ｍｉｎｕｍｉｎｄｕｓｔｒｙａｎｄｒｅｆｒａｃｔｏｒｙｉｎｄｕｓｔｒｙ .Ｂａｕｘｉｔｅｒｅ ｓｏｕｒｃｅｓｉｎＣｈｉｎａａｒｅｒｉｃｈ[1] .Ｔｈｅｅｘｐｌｏｒｅｄｒｅｓｅｒｖｅｓａｒｅ 2 .3ｂｉｌｌｉｏｎｔｏｎｓ .Ｈｏｗｅｖｅｒ ,ｍｏｓｔｏｆｔｈｅｍａｒｅｈｉｇｈａｌｕｍｉｎａａｎｄｈｉｇｈｓｉｌｉｃｏｎｄｉａｓｐｏｒｉｃｂａｕｘｉｔｅａｎｄｔｈｅｒａ ｔｉｏｏｆａｌｕｍｉｎｕｍｔｏｓｉｌｉｃｏｎｉ…     

中国拜耳法氧化铝生产技术的发展方向

应用一水硬铝石型铝生产溶出动力学及一水硬铝石型铝土矿中硅钛矿物的反应行为规律对现有的间接加强化溶出技术进行了技术上的剖析。认为现有的单流法溶出技术用于处理我国的一水硬铝石型铝土矿,都表现有某些方面的不足。我国自行开发成功的高温双流水溶出技术实现一水硬铝石矿间接加热强化溶出的适宜选择。     

Effect of hydroxamic acid starch on reverse flotation desilicate from diasporic bauxite

It is important to depress diaspore effectively in order to remove silicates from diasporic bauxite.A new water soluble polymer hydroxamic acid starch(HA-starch)was prepared.The effects of the product on the diaspore and kaolinite flotation were investigated and its reactive mechanism was studied by zeta potential measurement and FTIR.The results show that HA-starch can depress diaspore while make positive effect on kaolinite flotation at low pH value(pH below 6)The flotation recovery of diaspore was sharply decreased with the increase of concentration of HA-starch.The chemical adsorption of HA-starch on the surface of diaspore was revealed.     

Technology and mechanism of desilication from roasted diasporic bauxite in atmosphere

The leaching desilication technology of roasted diasporic bauxite in atmosphere by caustic soda solution was investigated. The optimum parameters were: the grinding fineness of the roasted bauxite -0. 076 mm and 80 % -85 %,leaching time 2h, Na2Ok100-150g/L, L/S 4-5, leaching temperature 90-95℃. The desilication rate 55.20% and concentrate A/S (mass ratio of A12O3 to SiO2) 9.90, as good as those obtained at pressure, were obtained respectivdy.Investigation of two-stage leaching shows that it can both improve desilication rate of roasted ore and reduce leaching time.When time of the first stage and the second stage is 30 min and 30 min respectively, desilication rate can reach 59.65 %.X-ray diffraction analysis of the concentrate has proved that desilication procedure is accompanied with the formation of sodium aluminosilicate hydrate. X-ray spectra also show that silica removed during leaching is amorphous silica. SiO2 occurrina as ouartz in raw ore or mullite formed during roasting can not dissolve in alkali solution.     

铝土矿中铝硅矿物晶体结构的综述

详细论述了国内外铝土矿资源中几种主要矿物的晶体结构特征,讨论了三种铝矿物之间及与硅矿物晶体结构之间的差异,及在磨矿过程中的解离特性,为铝土矿的浮选提供基础资料。     

我国的铝土矿资源和高效低耗的氧化铝生产技术

分析了我国一水硬铝石型铝土矿资源的特点及其对氧化铝生产工艺流程、能耗和成本的影响,论述了为实现我国氧化铝工业可持续发展,高效低耗地开发利用我国中低品位一水硬铝石矿资源的技术路线,提出了采用选矿拜耳法、石灰拜耳法、新并联法和串联法等新技术改进现有的拜耳法和联合法氧化铝生产工艺以及亟待开发的节能降耗和提高质量的重大新工艺和关键技术.     

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。