Effect of Fe_(2)O_(3)on the Structure,Physical Properties and Crystallization of CaO-Al_(2)O_(3)-SiO_(2)Glass

The calcium aluminosilicate-based glasses(CaO-Al_(2)O_(3)-SiO_(2),CAS)with different Fe_(2)O_(3)content(0.10wt%,0.50wt%,0.90wt%,and 1.30wt%)were prepared by traditional melt-quenching method.The glass network structure,thermal and mechanical properties,and crystallization behavior changes were investigated by nuclear magnetic resonance spectrometer,Fourier-transform infrared spectro-photometer,X-ray diffractometer,differential scanning calorimetry and field emission scanning electron microscope measurements.The change of Q^(n)in glass structures reveals the glass network connectivity decreases due to the increasing content of Fe_(2)O_(3)addition,resulting in the increasing of non-bridging number in glass structure.The glass densities slightly rise from 2.644 to 2.681 g/cm^(3),while Vickers’s hardness increases at first,from 6.469 to 6.901 GPa,then slightly drops to 6.745 GPa,with Fe_(2)O_(3)content increase.There is almost no thermal expansion coefficient change from different Fe_(2)O_(3)content.The glass transmittance in visible range gradually decreases with higher Fe_(2)O_(3)content,resulting from the strong absorption of Fe^(2+)and Fe^(3+)ions.The calculated activation energy from thermal analysis results first decreases from 282.70 to 231.18 kJ/mol,and then increases to 244.02 kJ/mol,with the Fe_(2)O_(3)content increasing from 0.10wt%to 1.30wt%.Meanwhile,the maximum Avrami constant of 2.33 means the CAS glasses exhibit two-dimensional crystallization.All of the CAS glass-ceramics samples contain main crystal phase of anorthite,the microstructure appears lamellar and columnar crystals.

Effects of Copper-Zinc Alloy Doped with Rare Earth Elements on Crystal of Calcium Carbonate

A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.

Determination of Crystallization Kinetics and Size Distribution Parameters of Agglomerated Calcium Carbonate Nanoparticles during the Carbonation of a Suspension of Lime

The reaction studied in this work is the synthesis of nanometric size calcium carbonate by carbonation of a suspension of lime, which represents the most common industrial route. The carbonation was proceeded in a pilot batch reactor. This article presents a method for the determination of nucleation and crystal growth rates of calcium carbonate by following two macroscopic parameters: the mass production rate by precipitation and the specific surface area. The results give a constant nucleation rate around 4 × 1015m-3 ·s-1 and a decreasing crystal growth rate between 0.2 and 2 × 10-10 m·s-1. It also provides the main characteristics of the monoparticle size distributions (i.e. the mean particle sizes and in situ coefficient of variation) in the agglomerates, which cannot be obtained by other known methods. For the carbonation carried out in this work, the mean mass particle size at the end of the reaction is about 300 nm and the coefficient of variation of 0.28 indicates a narrow particle size distribution of the monoparticles.

Crystal Structure of Calcium Complex with Cyanuric Acid Ligand［Ca（C3H3N3O3－O）（H2O）6］［（OH）（C3H2N3O3）］

The title compound[Ca(C3H3N3O3)(H2O)6][(OH)(C3H3N3O3)] crystallizes in the triclinic system,space group P1,with a=6.501(5),b=10.814(6),c=11.803(1) A,α=103.64(1),β=92. 72(3),γ=98. 82(4)°,V=793- 9(7) A3,Dc=l.77 g/cm3,Z=2,Mr=422. 32,λ(MoKα)=0.71069 A,μ=4.65 cm-1,F(000)=440,final R=0.045 and Rω=0.058 for 3422 observable reflections with I≥3σ(I).In the complex cation [Ca (C3H3N3O3)(H2O)6]2+,the Ca2+ is coordinated by an oxygen atom from cyanuric acid ligand and six oxygen atoms from water molecules forming a distorted pentagonal bipyramid geometry.The complex anions, OH- and C3H2N3O3-,are bound with the complex cation[(Ca(C3H3N3O3)(H2O)6]2+ by electrostatic force to form the title compound.

Influence of Konjac Glucomannan on the Crystallization Morphology and Structure of Calcium Oxalate

The influence of additive Konjac Glucomannan （KGM） in a variety of con- centrations on the crystallization morphology and structure of calcium oxalate （CaOxa） has been investigated by infrared spectroscopy, scanning electron microscope, X-ray diffraction and so on. The results showed KGM can complex with the Ca^2＋ ions; low concentration KGM prevents CaOxa from aggregating, raises the concentration of ions in the solution, reduces the quantity of crystals and inhibits their growth, and the crystals are round and blunt; while high concentration KGM promotes the growth of crystal, which appears in sheet-like or irregular shape. Only CaOxa monohydrate was observed in a certain system with or without the presence of KGM.

SYNTHESIS AND STRUCTURE OF HYDRATED LANTHANUM CARBONATE

以碳酸氢铵为沉淀剂合成了碳酸镧晶体。经Ｘ射线衍射测定，晶体属正交晶系，晶胞参数ａ＝０．８４８７ｎｍ，ｂ＝０．９５６４ｎｍ，ｃ＝０．４４８６ｎｍ。其结构与文献中提到的镧石型稀土碳酸盐的结构相接近。碳酸镧的红外光谱说明其内部存在着非等价的碳酸盐群。碳酸镧在热分解过程中，存在着稳定的中间产物Ｌａ２Ｏ３·ＣＯ２。

Formation mechanism and crystal simulation of Na_2O-doped calcium aluminate compounds

Calcium aluminate clinkers doped with Na2O were synthesized using analytically pure reagents CaCO3, Al2O3, SiO2 and Na2CO3. The effects of Na2O-doping on the formation mechanism of calcium aluminate compounds and the crystal property of 12CaO·7Al2O3 (C12A7) cell were studied. The results show that the minerals containing Na2O mainly include 2Na2O·3CaO·5Al2O3 and Na2O·Al2O3, when the Na2O content in clinkers is less than 4.26% (mass fraction). The rest of Na2O is mainly doped in 12CaO·7Al2O3, which results in the decrease of the crystallinity of 12CaO·7Al2O3. The crystallinity of 2Na2O·3CaO·5Al2O3 is also inversely proportional to the Na2O content in clinkers. The formation processes of 2Na2O·3CaO·5Al2O3 and 12CaO·7Al2O3 can be divided into two ways, which are the direct reactions of raw materials and the transformation of CaO·Al2O3, respectively. The simulation shows that the covalency of O-Na bond in Na2O-doped 12CaO·7Al2O3 cell is weaker than those of O-Ca and O-Al bonds. The free energy of the unit cell increases because of Na2O doping, which results in the improvement of chemical activity of 12CaO·7Al2O3. The leaching efficiency of Al2O3 in clinker is improved from 34.81% to 88.17% when the Na2O content in clinkers increases from 0 to 4.26%.

A New Route to the Synthesis of Barium Carbonate Crystals by the Induction of Bacillus Pasteurii

As one of the soil microorganisms, bacillus pasteurii exhibits good urease-produ-cing ability. A novel method is used to prepare BaCO3 crystals by the induction of bacillus pasteurii. The crystals have been characterized by XRD, SEM and FT-IR. X-ray diffraction analysis quantified that the BaCO3 crystals obtained belong to the orthorhombic crystal system. Examination by scanning electron microscopy identified that the BaCO3 crystals have different morphologies under different preparation conditions. FT-IR indicated that surfactant EDTA had great effect on the morphology of BaCO3 crystals. Different morphology crystals had uniform distribution and integral shape. The forming mechanism and influence of EDTA on the morphology of BaCO3 crystals have been discussed.

Synthesis and Crystal Structure of a Novel Ca(Ⅱ) Coordination Polymer Containing Dipyridine Dicarboxylic Ligand

The novel alkaline metal complex Ca（BPDCH）2 （1, BPDCH2 = 2,2＇-bipyri- dine-5,5＇-dicarboxylic acid） has been synthesized by the hydrothermal reaction of Ca（NO3）2·4H2O with 2,2＇-bipyridine-5,5＇-dicarboxylic acid. The molecular and crystal structures of complex 1 have firstly been characterized by FTIR, elemental analysis, and X-ray single-crystal diffraction. The 3D MOF structure of complex 1 was interpreted by the versatile binding modes-the intermolecular hydrogen bonds and π-π stacking interactions of 2,2＇-bipyridine-5,5＇-dicarboxylic acid ligand. The analysis results show complex 1 belongs to a coordination polymer with 3D MOF structure. The results of thermogravimetric analysis and solubility demonstrate complex 1 is a thermostable compound and does not dissolve in water and traditional organic solvents.

Synthesis and Crystal Structure of a Novel Hetero-bimetallic Complex with a Three-dimensional Network Structure: Bis(malonato)tetra(aqua)calcum(II)cobalt(II)

The title complex [CaCo（C3H2O4）2（H2O）4]n with a formula of C6HI2CaCoO12 and Mr=375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 14,195（9）, b = 7.708（5）, c = 13.441（8） A, β =119.575（9）°, V = 1279.0（14） A3, Dc= 1.948 g/cm^3,μ=1.803 mm^-1, F（000） = 764 and Z = 4. The final R = 0.0245 and wR = 0.0652 for 1344 observed reflections with I 〉 2σ（I）. The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate ligands. The Ca（Ⅱ） cation on a twofold axis is coordinated by two water molecules and six malonate O atoms. The Co（Ⅱ） cation which lies in a centre of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules, The structure comprises alternating layers along the [101] plane, with the shortest Co-Co distance of 6.961（5）A. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds.

Crystal Structure of a Three-dimensional Coordination Polymer {[Ca_3(μ_5-OOCCH_2OCH_2COO)_3(H_2O)_4]·4H_2O}_n

A novel three-dimensional coordination polymer, { [Ca3（μ5-OOC CH2OCH2COO）3（H20）4]·4H2O }n, has been synthesized with oxydiacetate as bridge ligand and structurally determined by X-ray crystallography. The crystal belongs to monoclinic, space group C21c with a = 17.805（2）, b = 9.3923（12）, c = 17.255（2）A, β= 107.838（5）°, V = 2746.8（6）A3, Mr = 660.58, C12H28Ca3O23, Dc = 1.597 g/cm^3,μ = 0.695 mm^-1, Z = 4, F（000） = 1376, GOOF = 1.027, R = 0.0303 and wR = 0.0660. In the complex there are two coordination modes for Ca（Ⅱ） ions, one coordinated by three μs-OOCCH2OCH2COO^2- bridge ligands together with two H2O molecules, and the other by five μs-OOCCH2OCH2COO^2- bridge ligands. In both coordination modes each Ca（H） ion assumes a distorted dipentapyramidal CaO7 geometry; whereas each oxydiacetate is coordinated with five Ca（Ⅱ） ions and acts as a pentdentates bridge ligand.

Synthesis, Crystal Structure and Magnetic Property of Disodium Biscarbonato cobaltate(Ⅱ) Tetrahydrate, Na_2Co(CO_3)_2·4H_2O

The title compound, Na 2Co(CO 3) 2·4H 2O, was synthesized by dropwise addition of 1.0 mL of 1 mol/L Co(CH 3COO) 2 to 50 mL of aqueous solution containing 7.0 g(66.0 mmol) of Na 2CO 3 and 2.5 g(29.8 mmol) of NaHCO 3 under stirring. A rose colored rhombohedral crystal grew by the slow evaporation of the solution of the title compoud at room temperature. The crystal structure was established on the basis of the single crystal X ray diffraction data. Na 2Co(CO 3) 2·4H 2O crystallizes in the monoclinic space group C2/c with a =0.856 6(1) nm, b =0.714 6(1) nm, c = 1 438 7(2) nm, β =97.59(1)° , V =0.873 0(2) nm 3 , D x=2.260 g/cm 3, F (000)=596, M r=296 99, μ (Mo K α)=21.06 cm -1 , Z =4 and the final R(F) =0.032 and wR(F 2) =0.068 on the basis of 947 reflections ( F 2 ≥ 2σ(F 0 2)). The crystal consists of H 2O molecules, Na + ions and 2D 2 ∞[Co(CO 3) 2] 2- layers extending parallel to (001). H 2O molecules and Na + cations are located between the 2D layers. Each Co atom is tetrahedrally coordinated by four O atoms from four CO 2- 3 groups with d (Co\_O)=0.206 5(2) nm, 0.207 6(2) nm and the angle of O\_Co\_O is in the range of 97.7(1)°—128.5(1)°. The CO 2- 3 group bridging two Co atoms via two O atoms deviates from D 3h symmetry with d (C\_O)=0.127 2(3)\_0.129 9(3) nm and the angle of O\_C\_O is in the range of 119.5(2)°\_123.4(2)°. Each Na atom, with two close Na neighbours at 0.338 4(2) nm and 0 346 7(2) nm, respectively, is octahedrally coordinated by six O atoms from four H 2O molecules and two carbonate groups belonging to two layers with d (Na\_O)=0.232 7(2)\_0.241 1(2) nm. Of two crystallographically different H 2O molecules, one forms hydrogen bonds to two CO 3 2- groups of one 2D layer, and the other to those from two different 2D layers. Na 2Co(CO 3) 2·4H 2O is antiferromagnetic below 16 K, and between 30\_300 K its magnetic behaviour obeys Curie Weiss law χ m(cm 3·mol -1 )=2.625/( T -12.1) with μ eff =4.5 B.M. at 298 K.

Synthesis and CrystalStructure of Dicesiumtrans-Dicarbonatotetraaquom agnesium ,Cs_2[Mg(CO_3)_2(H_2O)_4]

The title compound, Cs 2[Mg(CO 3) 2(H 2O) 4], was synthesized by the dropwise addition of an aqueous solution of Mg(NO 3) 2 to a stirred aqueous Cs 2CO 3/CsHCO 3 solution. A colorless needle shaped crystal was formed by slow evaporation. The crystal structure was established on the basis of the single crystal X ray diffraction data. Cs 2[Mg(CO 3) 2(H 2O) 4] crystallized in the orthorhombic space group Pbca (No. 61) with a =0.658 4(1) nm, b =1.257 9(1) nm, c =1.301 3(1) nm, \{ V =1.077 8 nm 3, Z =4, D x=2.971 g·cm -3 , μ =69.20 cm -1 , F (000)=888, T =298 K, final R =0.029 and R w=0.024 for 1 037 observed reflections. The crystal consists of Cs + cations and the complex trans [Mg(CO 3) 2(H 2O) 4] 2- anions with each Mg atom coordinated by the six oxygens of two carbonate groups and four water molecules [ d (Mg_O)=0.203 6(4), 0.207 4(4), 0.213 4(4) nm]. The complex trans [Mg(CO 3) 2(H 2O) 4] 2- anions are arranged in a strongly compressed bcc pattern. A 3D network was formed through the intermolecular hydrogen bonds. The Cs + cations are located in cavities, each being surrounded by nine oxygens of five complex anions with d (Cs_O)=0.306 1-0.348 8 nm. The CO 2- 3 group reveals a lowering of D 3h symmetry due to site and coordination effects, but not any observable deviation from co planarity [ d (C_O)=0.127 2(6), 0.127 5(7) , 0.130 5(6) nm and O_C_O=119.6(5)°, 120.1(5)°, 120.4(5)°].

Characterization of the Crystal Structure of Sesame Seed Cake Burned by Nd: YAG Laser

This paper reports obtaining of useful and high-value materials from sesame seed cake (SSC). For this purpose, SSC sample was burned for 30 s using Nd: YAG laser with output power 60 W. The products of this process and non-burned SSC were characterized by X-ray diffractometer (XRD), energy dispersive x-ray (EDX) and Fourier transform infrared (FTIR) so as to investigate its crystal structure and chemical components. XRD results of the SSC before burning process showed amorphous silica, rhombohedral phase of carbon, monoclinic phase of aluminum chloride, the hexagonal phase of moissanite-4H, (yellow, black) and hexagonal phase of graphite-2H, C (black). While the results of the burned SSC sample showed that the burning process using the power of Nd: YAG laser cased in appearing of crystalline hexagonal phase for silica and Carbon Nitride and converting the rhombohedral phase of Carbon into hexagonal phase. FTIR showed a number of absorbance peaks assigned to silica.

One-pot Synthesis of Bio-inspired Layered Materials of 3D Graphene Network/Calcium Carbonate

A bio-inspired layered material of reduced graphene oxide（RGOs） and calcium carbonate was synthesized via a one-pot strategy in DMF/H2O mixed solvent. The experimental results show that the product is a layered material of wrinkled RGOs networks and micron-sized calcium carbonate particles with uniform granular diameter and homogeneous morphology, which are distributed between the layered gallery of the graphene scaffold. The polymorph and the morphology of the in-situ produced calcium carbonate particles can be manipulated by simply changing the temperature scheme. Besides, the graphene oxide was reduced to a certain extent, and the hierarchical wrinkles were generated in the RGOs layer by the in-situ formation of the calcium carbonate particles. This work provides a facile and controllable strategy for synthesizing layered material of RGOs and carbonates, and also presents a platform for making three-dimensional porous wrinkled RGOs networks.

Crystal structures and hydrogenation behavior of (Ca_(0.9)Sr_(0.1))_8(Al_(1-x)Zn_x)_3 alloys

The crystal structures and hydrogenation behavior of the （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0, 0.1, 0.2, 0.3 and 0.4） alloys were investigated. The new phase （Ca,Sr）E（Al,Zn） was found whenx 〉 0.1. （Ca, Sr）E（Al,Zn） crystallizes in space group 14/mmm （A-139）. The lattice parameters were calculated to be a = b = 1.1616（2） nm, c = 1.6422（4） nm. Zn atoms occupy the 8h and 16n sites together with Al atoms. The （Ca0.9Sr0.1）8Al3 alloy only contains a single Ca8Al3 phase. The （Ca0.9Sr0.1）8（Al1-xZnx）3 alloys consist of Ca8Al3, CasZn3, Ca and （Ca,Sr）2（Al,Zn） phases when x is from 0.1 to 0.3. As x increasing to 0.4, the alloy consists of （Ca,Sr）E（Al,Zn）, Ca8Zn3 and Ca. The hydrogenated （Ca0.9Sr0.1）8Al3 and （Ca0.9Sr0.1）8（Al0.9Zn0.1）3 samples consist of CartE and Al. The （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0.2, 0.3 and 0.4） samples can be hydrogenated into CaH2, Al and CaZnl3 under a hydrogen pressure of 5 MPa at 473 K.

The Preparation of Ultra-fine Calcium Carbonate and Its properties Study

This article adopts the double decomposition method, select the appropriate experimental conditions and operation process, respectively add appropriate amount of sodium carboxymethyl cellulose （CMC） as crystal control agent to study the influence of crystalline of ultrafine calcium carbonate. The experimental results show that the different concentrations of CMC as crystal control agent on the morphology and crystal structure of calcium carbonate have obvious effect, which emerge morphology change from square to spherical, crystalline transition from calcite to aragonite. Thus, the results provide experimental data and theoretical basis for the use of different additives, and provide experimental basis and feasible solution for this kind of reaction.

Mineral transition and formation mechanism of calcium aluminate compounds in CaO-Al2O3-Na2O system during high-temperature sintering

The mineral transition and formation mechanism of calcium aluminate compounds in CaO-Al2O3-Na2O system during the hightemperature sintering process were systematically investigated using DSC-TG,XRD,SEM-EDS,FTIR,and Raman spectra,and the crystal structure of Na4Ca3(AlO2)10 was also simulated by Material Studio software.The results indicated that the minerals formed during the sintering process included Na4Ca3(AlO2)10,CaO·Al2O3,and 12 CaO·7 Al2O3,and the content of Na4Ca3(AlO2)10 could reach 92 wt%when sintered at 1200°C for 30 min.The main formation stage of Na4Ca3(AlO2)10 occurred at temperatures from 970 to 1100°C,and the content could reach82 wt%when the reaction temperature increased to 1100°C.The crystal system of Na4Ca3(AlO2)10 was tetragonal,and the cells preferred to grow along crystal planes(110)and(210).The formation of Na4Ca3(AlO2)10 was an exothermic reaction that followed a secondary reaction model,and its activation energy was 223.97 kJ/mol.

Formation kinetics and transition mechanism of CaO·SiO2 in low-calcium system during high-temperature sintering

The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio of CaCO3 to SiO2 is 1.0,β-2CaO·SiO2 forms firstly during the heating process,and then CaO·SiO2 is generated by the transformation reaction of pre-formed 2CaO·SiO2 with SiO2.3CaO·SiO2 and 3CaO·2SiO2 do not form either in the heating or sintering process.Rising the sintering temperature and prolonging the holding time promote the phase transition of 2CaO·SiO2 to CaO·SiO2,resulting in the sintered products a small blue shift and broadening in Raman spectra.The content of CS can reach 97.4%when sintered at 1400℃ for 1 h.The formation kinetics of CaO·SiO2 follows the second-order chemical reaction model,and the corresponding apparent activation energy and pre-exponential factor are 505.82 kJ/mol and 2.16×10^14 s^−1 respectively.

Preparation of spherical cobalt carbonate powder with high tap density

Spherical cobalt carbonate with high tap density, good crystallization and uniform particle size was prepared by controlled chemical crystal method using cobalt chloride and ammonium bicarbonate as cobalt source and precipitator. The effects of pH value and reaction time on crystallization and physical properties of cobalt carbonate were studied. The results show that the key factors influencing the preparation process of spherical cobalt carbonate with high tap density and good crystallization are how to control pH value (7.25±0.05) and keep some reaction time (about 10 h). Co4O3 was prepared by sintering spherical morphology CoCO3 samples at varied temperatures. The results show that as the decomposition temperature increases, the as-obtained Co4O3 products with porous structure transform into polyhedral structure with glazed surface, and simultaneously the cobalt content and tap density increase. However, the specific surface area shows a trend of decrease.