Effects of Na2SiF6 on Preparing Mullite Material with Sludge from the Aluminum Profile Factory and Pyrophyllite

In this research,the mullite material with sludge from aluminum profile factory and pyrophyllite as primary raw materials was prepared. Based on the optimal formula,optimal calcining temperature and holding time determined in the research,effects of Na2SiF6 mineralizer on crystal structure,microstructure and properties of mullite were discussed to determine the optimal addition of Na2SiF6 mineralizer. With XRD and SEM methods,crystal structure and microstructure of the test samples were characterized; with Rietveld Quantification method,contents of various crystal phases in the test samples were determined; properties of the test samples were tested. In combination with the structural and property analysis results,the optimal Na2SiF6 addition was determined to be 2%. Correspondingly,the content of solid solution of mullite-Al4.59Si1.41O9.7 was 96.9wt%,the bulk density was 2.10 g/cm3,the degree of porosity was 27.0%,the water absorption rate was 12.8%,the rupture strength was 24.30 MPa and primary thermal-shock rupture strength retention rate was 87.4%.     

Researches on the Structure and Properties of Mullite Solid Solution Made from Industrial Waste

1 INTRODUCTION The mullite has excellent properties of high tem- perature thermodynamics and mechanics, such as corrosion resistance, creep resistance, thermal shock resistance and high hot strength at high temperature. So it can be used as the inner lining of industrial furnace, thermal insulator material, crucible, protec- ting tube and electronic packaging material, which are widely used in such industries as metallurgy, ceramics, cement, and fireproof materials[1]. So far there has no …     

Influence of TiO_2 Mineralizer on the Crystalline Structure of Cordierite Synthesized from Aluminum Slag

By adding small amount of TiO2, aluminum slag could be used to synthesize cor-dierite, α-Al2O3, TiO2 and dehydrated talc could generate solid solution to accelerate the solid-state reaction to form cordierite. The experimental results show that the content of cordierite increases with the increase of TiO2 added. 3.0% of TiO2 is determined to be the best amount, because all crystalline substances are converted into cordierite at this content. Philips X‘pert plus software analysis shows that when the content of TiO2 is from 0 to 1.0%, cordierite has the same hexagonal structure as the single crystal and the lattice parameters change slightly; when the content of TiO2 is from 1.0 to 2.0%, the cordierite still keeps hexagonal structure but the lattice parameters change greatly; when the content of TiO2 is from 2.0 to 3.5%, the cordierite is converted from hexagonal into rhombic and the lattice parameters change accordingly.     

Influence of Cr2O3 on the Structure and Property of Mg-Al Spinel Synthesized by Waste Slag in Aluminum Factory

Via the solid phase reaction, Mg-Al spinel has been synthesized by using industrial waste slag from aluminum factory, basic magnesium carbonate and a little amount of clay as the main raw materials. The influences of Cr2O3 mineralizer on crystalline structure, micro-morphology and properties of synthesized Mg-Al spinel are discussed. The synthesized product was characterized by using XRD and SEM, and the relative contents of each crystalline phase are calculated by relevant analytical software such as Philips plus, Rietveld quantification and so on. The experimental results show that a certain amount of Cr2O3 is helpful to the formation of Mg-Al spinel, and when the addition of Cr2O3 is 2.0%, Mg-Al spinel in the system exists in the form of solid solution (Mg0.68Al0.32)(Al0.84Mg0.16)2O4 whose content is the highest reaching 91%. Then the corresponding indexes of each property are as follows: water absorption 3.0%, apparent porosity 9.8%, bulk density 3.36 g·cm-3, and flexural strength 83.32 MPa. Therefore, we can confirm that the optimum addition of Cr2O3 mineralizer is 2.0%.     

Influence of Impurity Na2O on Crystalline Structure of Cordierite Synthesized from Aluminum Sludge

Waste aluminum sludge, talc powder and clay were used to synthesize cordierite in this research. The impurities, such as Fe2O3, CaO, K2O and Na2O, in the raw materials have some influence on the structures and properties of the materials. In this paper, we mainly discuss the impact of impurity Na2O on the structure of cordierite, based on which the permitted amount of Na2O was determined. The results show that Na2O with the amount less than 0.6% has little influence on the cordierite formation; while when its amount increasing from 0.6% to 0.7%, the content of cordierite decreases from 86% to 84% and the permitted amount for Na2O in the raw materials is less than 6% with the best amount less than 0.3%. X‘pert plus software analysis results show the impurity Na2O has no influence on the cordierite space group and only the lattice parameters vary slightly; but it has much influence on the structure of Mg-AI spinel and the lattice parameters are much changed.     

Effects of Calcining Temperature and Holding Time on the Synthesis of Aluminum Titanate

We aim in this research at synthesizing high-purity aluminium titanate with sludge from the aluminium profile factory by shock cooling method, and mainly discuss the effect of calcining reaction temperature and holding time on crystalline, microstructure and content of aluminum titanate materials to determine the preferred calcining temperature and holding time. XRD and SEM methods were utilized to characterize the crystalline and microstructure of each specimen, Rietveld Quantification software was used for the determination of different crystalline contents of specimens, and Philips plus software was applied to determine the cell parameters of aluminium titanate in different specimens. According to the experimental results, preferred calcining temperature is determined as 1400℃ and preferred holding time is 2 h, at which the grains of aluminum titanate grow completely and the purity of aluminum titanate is 97.2wt%.     

二维含镧链异核金属化合物的合成、结构和磁性研究

水热法合成了3个层状异核金属化合物[Ln(idaH)M(ida)₂]_n·0.5nH₂O,(H₂ida=亚氨基二乙酸,Ln=Nd,M=Co (1);Ln=La,M=Co (2);Ln=La,M=Ni (3))。进行了晶体结构测定,红外光谱分析、能谱分析与磁性能分析。3个化合物除金属原子不同外具有相同的结构,其晶体都属于单斜晶系,C2/c空间群。单晶结构表明该结构含有由十配位的Ln通过羧基氧连接而成的链,六配位的3d金属(Co、Ni)交替地处在链的两边,形成了带状结构,带状链通过配体连成二维结构,通过氢键形成三维骨架。     

Role of MnO on the Mullitization Behavior of Al2 O3-SiO2 Gels

Gels were synthesized from solutions of tetraethylorthosilicate (TEOS) and aluminium nitrate (with and without manganese nitrate).The structural evolution of the gels as a function of manganese content and heat-treatment temperature was studied by visible spectrophotometry (VIS), electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the presence of manganese can induce mullitization at lower temperatures. However, the effect of manganese depends on its content and how it enters into the mullite structure.     

Studies on the Structure and Properties of Multiphase Al_2O_3 Abrasion-resistant Ceramics

1 INTRODUCTION Due to its high intensity, high hardness, high tem- perature resistance, corrosion resistance and abra- sion resistance, Al2O3 abrasion-resistant ceramic is widely applied in many fields, such as metallurgy, minerals, electric power, building materials and che- mical engineering as grinding medium in the ball grinder. The properties of Al2O3 ceramic are positi- vely correlated to its purity: the higher the purity is, the better the properties of the product are, but cor- r…     

Cobalt(II)/silver(I) coordination polymers with bis(2-methylbenzimidazole) and polycarboxylate ligands

Three coordination polymers, [Co(L)(tbta)]_n (1), [Ag(L)(H₂O)·(Hhpht)]_n (2) and [Ag₂(L)_1.5(oba)]_n (3) (L = 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene, H₂tbta = tetrabromoterephthalic acid, H₂hpht = homophthalic acid, H₂oba = 4,4′-oxybis(benzoic acid)), have been hydrothermally synthesized and structurally characterized. Complex 1 displays a 2-D uninodal 4-connected sql network, 2 and 3 feature chain structures, which further generate 2D supramolecular networks through hydrogen bonding interactions. The thermal and fluorescence properties of 1–3 have been carried out and discussed.     

Rietveld Refinement of Tetragonal V-ZrO2 Solid Solutions Obtained from Gels by X-ray Powder Diffraction

The crystal structure of three tetragonal V_xZr_1−xO₂ solid solutions, with x=0.025, 0.05, and 0.075, prepared by heating dried gel precursors at 450°C in air atmosphere, have been determined by Rietveld refinement on the basis of powder X-ray powder diffractometer data. They contain V⁴⁺ cations surrounded by eight oxygens, four at a distance between 2.079 and 2.093 Å and another four at longer distances between 2.369 and 2.348 Å. The estimation of the crystal average oxygen position from the X-ray lattice parameter of V_xZr_1−xO₂ conform with the relationship proposed by Howard et al. (J. Am. Ceram. Soc. 81, 241 (1998)).     

Crystal Structure and Characterization of a Novel 2D Layered Compound Assembled from Paradodecatungstate Clusters

A novel 2D layered compound （H4HMTA）2（H3O）2{Na2（H2O）6（H2W12O42） }C12-11H2O （HMTA = hexamethylenetetraamine） has been synthesized and characterized by elemental analyses, IR, UV-Vis and X-ray diffraction. C12H74CI2N8Na2O61W12 （Mr = 3629.87） crystallizes in the triclinic system, space group P1 with a = 10.5518（2）, b = 12.1837（2）, c = 14.3088（2） A, α = 112.9470（10）, β = 93.1310（10）, γ= 106.1530（10）°, V = 1599.20（5）A3 Dc = 3.769 g.cm^-3, Z = 1, μ（MoKα） = 21.705 mm^-1, F（000） = 1634, the final R = 0.0287 and wR = 0.0686 for 5846 observed reflections with I 〉 2σ（I）. The 2D layered network is assembled from paradodecatungstate clusters linked by simple sodium-oxo bridging groups. The compound exhibits electrocatalytic activities toward both reduction and oxidation of nitrite.     

Ce-Zr固溶体的纯度及其在三效催化剂中的作用

采用溶胶－凝胶法和有机溶剂分解法,制备了Ｃｅ－Ｚｒ固溶体。应用ＸＲＤ和ＬＲＳ谱测试,详细研究了经不同温度焙烧后固溶体的结构、晶相和热稳定性,并进行了储氧量、比表面积的测定和催化活性评价。结果表明,ＸＲＤ和ＬＲＳ相结合,可以较好地表征固溶体,并且储氧量高,但热稳定性较有机溶剂分解法制得的固溶体差;含富铈固溶体的三效催剂剂老化后的催化活性明显高于含纯ＣeＯ２的三效催化剂。     

Effects of Composition on the Structure and Capacitive Properties of Ti/(ZrO2)x(RuO2)1-x Electrodes

<正>A series of nominal composition Ti/(ZrO_2)_x(RuO_2)_(1-x) (0.1≤x≤0.9) coatings chan- ged in 10% steps was deposited on titanium substrate from RuCl_3·nH_2O and ZrCl_4 containing ethanol solution by thermal decomposition method. The X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) and electrochemical tests were performed to clarify the effects of ZrO_2 content on the structure and capacitive property of Ti/(ZrO_2)_x(RuO_2)_(1-x). The results show that by adding ZrO_2 into the coatings the degree of crystallization of RuO_2 decreases. The specific capacitance firstly increases and then deceases with the increase of ZrO_2 content in the mixed oxide coatings. The film of Ti/(ZrO_2)_(0.6)(RuO_2)_(0.4) consisting of amorphous matrix and fine nano-crystalline RuO_2 (about 4 nm) has the maximum specific capacitance of 713.27 F/g(RuO_2).     

由MCl2(M=Zn，Cd)与咪唑-4，5-二羧酸和1，4-双(咪唑-1-基)丁烷构筑的两个二重穿插二维配位聚合物的合成、结构和性质

以2∶1∶4物质的量比的咪唑-4,5-二羧酸(H3IDC),1,4-双(咪唑-1-基)丁烷(bib)和ZnCl2或CdCl2为反应物,在水热条件下分别得到了1个二重穿插的二维锌(Ⅱ)配位聚合物{[Zn2(IDC)(bib)Cl].H2O}n(1)和1个二重穿插的二维镉(Ⅱ)配位聚合物[Cd2(HIDC)(bib)1.5Cl2]n(2)。用元素分析、红外光谱以及单晶X-射线衍射结构分析对它们的组成和结构进行了表征,并对它们的热稳定性和荧光性质进行了初步的研究。     

Synthesis, Structures, Fluorescence and Magnetism of Two Lanthanide Metal-organic Frameworks with CaF2 Topology Based on Silicon-centered Tetrahedral Ligand

Two 3D multifunctional lanthanide metal-organic frameworks(MOFs), Pr(HTCPS)(H₂O)·2DMF·C₂H₅OH· 5H₂O(JUC-93) and Pr₃(TCPS)₂(NO₃)(H₂O)₄(DMA)₂·2DMA·C₂H₅OH·3H₂O(JUC-94)[H₄TCPS=tetrakis(4-carboxyphenyl)- silane, DMF=N,N'-dimethylformamide, DMA=N,N'-dimethylacetamide and JUC=Jilin University China] were synthesized by the self-assembly of a rigid silicon-centered tetrahedral carboxylate ligand H₄TCPS and Pr(III) ions in different solvothermal reactions. X-Ray crystallography revealed that they exhibited a rare CaF₂ topology framework, constructed from the 4-connected tetrahedral TCPS unit with the 8-connected dinuclear praseodymium cluster unit and trinuclear praseodymium cluster unit, respectively. In addition, the luminescent and magnetic properties of the two compounds were investigated.     

Synthesis,Structure and Luminescent Property of a New Cd(Ⅱ) Complex Containing 2-Propyl-imidazole-4,5-dicarboxylate

A new Cd(Ⅱ) complex([Cd(H2PIDC)2]n) with singly deprotonated 2-propyl-imidazole-4,5-dicarboxylate as bridging ligand was synthesized and characterized by X-ray diffraction method.Crystal data:monoclinic,space group P21/c,with a=8.2547(11),b=10.7071(15),c=13.9131(14),β=126.164(5)o,V=992.8(2)3,C16H18N4O8Cd,Mr=506.74,Z=2,Dc=1.695g/cm3,F(000)=508,μ=1.151 mm-1,R=0.0296 and wR=0.0812 for 1581 observed reflections.Singly deprotonated ligands(H2PIDC-) act as μ3-bridge and join the Cd(Ⅱ) atoms into a 2-D layer structure.The 2-D layers are further linked by intermolecular hydrogen bonds into a 3D network.The luminescent property of the complex was also investigated.     

基于钛锡载体的SCR低温脱硝催化剂的表面性质研究

采用共沉淀法制备TiO₂-SnO₂固溶体,浸渍法负载CeO₂得到一系列xCeO₂/TiO₂-SnO₂负载型催化剂,在模拟NH₃选择性催化还原NO_x(NH₃-SCR)反应条件下考察催化剂低温脱硝活性。通过X射线衍射(XRD)、比表面积测定(BET)、程序升温还原(H₂-TPR)、程序升温脱附(NH₃-TPD)、高分辨率透射电子显微镜(HRTEM)、原位漫反射傅里叶变换红外光谱(in situ DRIFTS)等表征技术,研究了氧化铈负载后催化剂的微观结构、表面物种的存在状态、表面酸位等表面性质及NH₃吸附特性。结果表明,Ce:Ti物质的量比为0.1时,催化剂催化脱硝反应活性最高,同时具有较宽的温度窗口(250~300℃)和热稳定性;铈的过量负载会导致催化剂比表面积减小、活性窗口变窄,同时其氧化还原能力和NH₃吸附能力也减弱。NH₃-TPD结果显示,CeO₂的负载导致催化剂NH₃在弱酸及中等酸位的吸附显著增强,与催化剂NH₃-SCR最佳反应物温度降低有关。in situ DRIFTS表明,xCeO₂/TiO₂-SnO₂催化剂的Lewis酸位和Brønsted酸位强度均明显增强,同时,在1657~1666cm^-1处出现新的Brønsted酸位,参与SCR反应的主要物质是NH₄⁺分子。     

Effects of Heat Treatment on Photocatalytic Property of Sol-Gel Derived Polycrystalline TiO2

Polycrystalline TiO₂ in the bulk form was prepared by hydrothermal treatment of amorphous TiO₂ gel, and its photocatalytic activity for degradation of ethanol and physical properties were investigated after drying and calcination (300–650°C). The maximum photocatalytic activity reached when the polycrystalline TiO₂ was calcinated at temperatures from 300 to 500°C, which was almost the same as for a commercial TiO₂ powder. It was markedly reduced above 600°C. Photocatalytic activity of TiO₂ was affected by crystal growth of anatase, progress of sintering, anatase-rutile transformation and morphology of the polycrystalline TiO₂. It was a characteristic of the polycrystalline TiO₂ prepared in this study that the photocatalytic activity did not vary so much with the calcination temperature in the range of 300–500°C.