Synthesis of γ-alkoxy-propylamines and their collecting properties on aluminosilicate minerals

γ-alkoxy-propylamines, C12 H25 O(CH2 )3 NH2, C14 H29 O(CH2)3 NH2, C16 H33 O(CH2)3 NH2, C18 H37 O-(CH2)3NH2 were synthesized from aliphatic alcohol and acrylonitrile. The flotation tests of kaolinite, pyrophyllite and illite were conducted. The flotation mechanisms were explained in view of the structures of reagents and alumin ium silicate minerals, zeta potential and Fourier transform infrared spectrum measurements. The results show that the synthesized r-alkoxy-propylamines are more effective than dodecyl amine for flotation of kaolinite, pyrophyllite and illite. For flotation kaolinite and illite, the collecting ability is in the order of C18 H37 O(CH2)3 NH2 ＞C16 H33O(CH2)3 NH2 ＞C14 H29O(CH2 )3 NH2 ＞C12 H25O(CH2)3 NH2, but the r-alkoxy-propylamines types of collectors have almost the same collecting ability on pyrophyllite,which demonstrating that γ-alkoxy-propylamines are new selective collectors for reverse floatation to remove aluminium silicate minerals from bauxite.     

Flotation de-silicating from diasporic-bauxite with cetyl trimethylammonium bromide

1　INTRODUCTIONTheZetapotentialsofkaolinite ,illiteandchlo riteweremeasuredforthecoalflotation ,allthesethreeclaymineralswerenegativelychargedinthepHrangeof 2 .5 11.0 [1] .Theadsorptionofsodiumdode cylsulfateanddodecyltrimethylammoniumchlorideontokaolinitewasstudiedintheabsenceandpresenceofsodiumhexametaphosphate .Itwasfoundthatthepresenceofthelongchainphosphatedecreasedad sorptionoftheanionicsurfactantbutincreasedthead sorptionofthecationicsurfactant[2 ] .Acommercialmonoetheramineandac…     

Effect of quaternary ammonium salts on flotation behavior of aluminosilicate minerals

The electrokinetic properties and flotation of diaspore,kaolinite,pyrophyllite and illite with quaternary ammonium salts collectors were studied.The results of flotation tests show that the collecting ability of quaternary ammonium salts for the four minerals is in the order(from strong to weak)of octadecyl dimethyl benzyl ammonium chloride(ODBA),cetyl trimethyl ammonium bromide(CTAB),dodecyl trimethyl ammonium chloride(DTAC).Under the condition of alkalescence,it is possible to separate the diaspore from the silicate minerals such as kaolinite,illite and pyrophyllite using quaternary ammonium salts as collector.Isoelectric points(IEP)of diaspore,kaolinite,pyrophyllite and illite are pH=6.0,3.4,2.3 and 3.2,respectively.Quaternary ammonium salts can change ζ-potential of the aluminosilicate minerals obviously.The flotation mechanisms were explained by ζ-potential and Fourier transform infrared spectrum(FT-IR)measurements.The results demonstrate that only electrostatic interaction takes place between aluminosilicate     

碳酸钠对细粒铝硅酸盐矿物分散行为的影响

碳酸钠（Na2CO3）是铝土矿浮选脱硅工艺中的高效分散剂，通过沉降试验系统地研究了pH值和Na2CO3用量对一水硬铝石、高岭石、伊利石和叶腊石分散行为的影响．试验结果表明，4种单矿物在pH〈4的酸性条件下形成显著聚团，在碱性条件下则呈分散状态．其中，伊利石和叶蜡石在pH〉6，高岭石和一水硬铝石在pH〉9时处于较好分散状态．动电位测定和DLVO理论计算结果表明，添加Na2CO3后，4种单矿物的表面ζ电位的负值均显著增大，导致矿物颗粒之间的静电排斥作用增大，从而增强了4种矿物颗粒间的分散性．     

Synthesis and Characterization of Novel Chromium Catalyst and Polyethylene with High Molecular Weight

1Introduction Chromiumcatalystsplayaveryimportantroleinthe developmentofcoordinationpolymerizationofalkenes.ThechromiumbasedheterogeneousPhillipscatalystob tainedbyimpregnationofCroxidesonsilicaandthe UnionCarbideUnipolcatalystsystemderivedfromCp2Cr absorbedonsilica,arebothusedinthelarge scaleindus trialproductionofpolyolefines.Theslurry polymerization processiscurrentlyproducingaboutone thirdofthetotal amountofHDPEintheworldwiththesecatalysts[1].Dif ferentfromtheworldfamousZiegler Natta…     

铝硅酸盐矿物新型浮选捕收剂的研究

考察了自行合成的新型阳离子表面活性剂QAS222对高岭石、叶蜡石和伊利石等铝硅酸盐矿物的浮选行为,试验研究结果表明：广泛矿浆pH范围内,新型阳离子表面活性剂QAS222对铝硅酸盐矿物既表现出较强的捕收力,又显示良好的选择性,是铝硅酸盐矿物的有效捕收剂,可应用于铝硅酸盐矿物的浮选富集,同样也可用于铝土矿、铁矿、萤石矿等选别过程的反浮选脱硅;在矿浆pH=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．     

Synthesis and characterization of layered perovskite-type organic-inorganic hybrids (R-NH3)2(CH3NH3)Pb2I7

Layered organic-inorganic hybrids containing bilayer perovsikte (R-NH3)2(CH3NH3)Pb2I7 (where R=C12H25,C6H5C2H4) were synthesized by reactions in solution. The influences of the solvents and the reactant ratio on the structures of the products were investigated. The structures and the properties of the hybrids were characterized using X-ray diffraction (XRD) and ultraviolet and visible (UV) adsorption spectra. For comparing with the bilayer perovskite hybrids in structure and band gap magnitude, the hybrids containing monolayer perovskite (R-NH3)2PbI4 were also synthesized and characterized. The results demonstrate that the thickness of inorganic layer has obvious effect on the tunneling magnitude of the band gap but the organic part can be micro actuator of band gap.     

Low pressure synthesis of boron nitride with (C2H5)2O · BF3 and Li3N precursor

Cubic boron nitride(c-BN) was synthesized through benzene thermal method at a lower temperature of 300 °C by selecting liquid (C₂H₅)₂O · BF₃ and Li₃N as reactants. Hexagonal boron nitride(h-BN) and orthorhombic boron nitride(o-BN) were also obtained. The samples were characterized by X-ray powder diffractometry and Fourier transformation infrared spectroscopy. The results show that all the BF₃, BCl₃ and BBr₃ in the same family compounds can react with Li₃N to synthesize BN since the strongest bond of B-F can be broken. Compared with BBr₃, liquid (C₂H₅)₂O · BF₃ is cheaper, less toxic and more convenient to operate. Li₃N not only provides nitrogen source but also has catalytic effect on accelerating the formation of c-BN at low temperature and pressure. Foundation item: Projects(20273007,50372006) supported by the National Natural Science Foundation of China     

Selective catalytic reduction of NO with NH3 over sol-gel-derived CuO-CeO2-MnOx/γ-Al2O3 catalysts

Granular CuO-CeO₂-MnO _x /γ-Al₂O₃ catalysts were synthesized by the sol-gel method. The performance of the CuO-CeO₂-MnO _x /γ-Al₂O₃ catalysts for the selective catalytic reduction (SCR) was studied in a fixed bed system. Preliminary tests were carried out to analyze the behavior of NH₃ and NO over catalyst in the presence of oxygen. The optimum temperature range for SCR over the CuO-CeO₂-MnO _x /γ-Al₂O₃ catalysts is 300–400 °C. The catalysts maintain nearly 100% NO conversion at 350 °C. The °C NH₃ oxidation experiments show that both NO and N₂O are produced gradually with the increase of temperature. The catalysts in this experiment have a stronger oxidation property on NH₃, which improves the denitrification activity at low temperature. The over-oxidation of NH₃ at high temperature is the main cause leading to a decrease in the NO conversion. The NH₃ and NO desorption experiments show that NH₃ and NO can be adsorbed on CuO-CeO₂-MnO _x /γ-Al₂O₃ granular catalysts. The transient response of NH₃ and NO indicates that the SCR reaction proceeds in accordance with the Eley-Rideal mechanism. The adsorbed NO has little influence on the denitrification activity in SCR process. Foundation item: Projects (50776037, 50721005) supported by the National Natural Science Foundation of China     

Asymmetric synthesis of 3β-acetoxy-17,17-ethylendioxy-15β, 16β-methylene-5-androsten-7β-ol

3β-acetoxy-17, 17-ethylendioxy-15β, 16β-methylene-5-androsten-7β-ol(I) was prepared by 3 steps from 3β-acetoxy-15β, 16β-methylene-5-androsten-17-one (II) with overall yield of 52.7%. Thus, interaction of ethylene glycol and material (II) gave 3β-acetoxy- 17, 17-ethylendioxy-15β, 16β-methylene-5-androsten (III) which was subsequently oxidated and stereoselectively reduced to produce compound(I). The normal influencing factors, such as the types of oxidants and reductives, the mole ratio of reactants, the reaction temperature, and the addition ways of reactants, in oxidation and reduction were discussed. The results show that the oxidation rate order is CrO₃-C₅H₅N (1:1, mole fraction)>CrO₃-C₅H₅N(1:2)>(C₅H₅NH)₂Cr₂O₇ in terms of the oxidant, the yield of the oxidation becomes higher with increasing the oxidant stoichiometry and raising the reaction temperature. And the optimum condition is that the reaction temperature is at 30 °C, and n(III)/n(CrO₃-C₅H₅N(1:2))=1:20. The yield of the −7β alcohol order with Li[Al(OC(CH₃)₃)₃H] (e. g. 78.6%) is more than that with NaBH₄ (e. g. 14.5%) in terms of the reductive agent and the reduction rate decreases in the course of reaction. The compound (I) is characterized by IR and MS. Foundation item: Project (1357) supported by the Excellent Young Teachers Program of the Ministry of Education of China