Effects of CFB Ash on the Adsorption Mechanism of Polycarboxylate Superplasticiser

The effects of circulating fluid bed(CFB) ash on the adsorption performance of polycarboxylate superplasticiser and the mechanism of this influence on the dispersive property of the polycarboxylate superplasticiser were investigated by determing the cement paste fluidity, total organic carbon adsorption, infrared spectroscopic analyses and ζ potential test. The experimental results show that the addition of an inorganic salt into the mixture to change the content of SO_4~(2-)and Fe_2 O_3 can improve the adaptability between the CFB ash and polycarboxylate superplasticiser. Adsorption may occur between the polycarboxylate superplasiciser and Fe_2 O_3, SO_4~(2-)or other components in CFB ash, leading to a significant reduction in paste fluidity. As the content of Na_2 SO_4 in CFB ash reaches 3% or Fe_2 O_3 reaches 9%, the paste loses its liquidity. The organic carbon content in the liquor decreases with an increase in Na2_ SO_4 or Fe_2 O_3 content. Adding some Ba(NO_3)_2 and Na_2 S to the liquor can recover the organic carbon content to a certain extent, and the absolute value of ζ potential will increase. The addition of Ba(-NO_3)_2 or Na_2 S reduces the adsorption property of Na_2 SO_4 or Fe_2 O_3 in CFB ash on the polycarboxylate superplasticiser.     

Influence of crucible material on the microstructure and properties of iron rich glass-ceramics

Slag glass melting is usually performed on a laboratory scale in crucibles, which are economically viable tools for the production of slag glass-ceramics. In this work, quaternary CaO-Al₂O₃-MgOSiO₂ (CAMS) glass-ceramics were prepared by melting the tailing of Bayan Obo mine tailing, blast furnace slag, and fly ash in alumina and graphite crucibles. The effect of the crucible material on the microstructure and properties of the glass-ceramics was investigated using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and inductively coupled plasma atomic emission spectroscopy. Results indicated that the contents of Al₂O₃ and Fe₂O₃ in the initial glass were significantly changed by the corrosion of the alumina crucibles during the glass melting process and by the reducing action of the graphite crucibles. The main crystal phases of glass-ceramics melted in alumina crucibles and graphite crucibles were Ca (Mg, Fe, Al) (Si, Al)₂O₆, coesite and Ca (Mg, Al) (Si, Al)₂O₆, respectively. According to these findings, we conclude that the microstructure and properties of the glass-ceramics are affected by the crucibles.     

Preparation and electrochemical properties of Co3O4/graphite composites as anodes of lithium ion batteries

Co₃O₄/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis (TG/DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co₃O₄/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mA·h/g as the calcination temperature increases from 300 to 500 °C, and the Co₃O₄/graphite composites synthesized at 400 °C show the best cycling stability without capacity loss in the initial 20 cycles. The CV profile of the composite presents two couples of redox peaks, corresponding to the lithium intercalaction/deintercalation for graphite and Co₃O₄, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.     

高级氧化组合工艺协同净化微污染水的示范生产实验

为考察催化氧化-UV/H_2O_2-生物活性炭(BAC)高级氧化组合联用工艺在实际生产中对微污染水源水的的处理效能,在淮南某水厂示范工程对微污染淮河水进行了生产实验.结果表明,催化臭氧氧化-BAC组合联用工艺对水中的UV_(254)、DOC、氨氮、CODMn及THMFP均有较好的去除效果,且不会带来溴酸盐的问题.催化臭氧氧化工艺对UV_(254)、DOC、CODMn的平均去除率分别为21.8%、8.1%、10.8%.BAC对氨氮有很好的去除效果,最高去除率可达61%;对DOC和COD_(Mn)的平均去除率分别为10.4%和15.3%.催化臭氧氧化接触池对THMFP的平均去除率为34.9%,最高去除率可达53.2%.UV/H_2O_2在示范性生产实验中,对进一步提高有机物的去除能力有限;在实际生产设计中,考虑UV分解剩余臭氧的效用建议采用:催化臭氧氧化-UV-BAC-砂滤是确保饮用水出水安全可靠的高级氧化工艺必要的组合工艺模式.研究结果可为各自来水厂处理低温低浊水、提高出厂水水质以及自来水厂整体工艺的提升改造提供借鉴和参考.     

Al2O3 coating for improving thermal stability performance of manganese spinel battery

The synthesis of Al₂O₃-coated and uncoated LiMn₂O₄ by solid-state method and fabrication of LiMn₂O₄/graphite battery were described. The structure and morphology of the powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemical and overcharge performances of Al₂O₃-coated and uncoated LiMn₂O₄ batteries were investigated and compared. The uncoated LiMn₂O₄ battery shows capacity loss of 16.5% after 200 cycles, and the coated LiMn₂O₄ battery only shows 12.5% after 200 cycles. The uncoated LiMn₂O₄ battery explodes and creates carbon, MnO, and Li₂CO₃ after 3C/10 V overcharged test, while the coated LiMn₂O₄ battery passes the test. The steadier structure, polarization of electrode and modified layer are responsible for the safety performance.     

Thermodynamics of chromite ore oxidative roasting process

To explicate the thermodynamics of the chromite ore lime-free roasting process,the thermodynamics of reactions involved in this process was calculated and the phrases of sinter with different roasting times were studied.The thermodynamics calculation shows that all the standard Gibbs free energy changes of the reactions to form Na2CrO4,Na2O·Fe2O3,Na2O·Al2O3 and Na2O·SiO2 via chromite ore and Na2CO3 are negative,and the standard Gibbs free energy changes of the reactions between MgO,Fe2O3 and SiO2 released f...     

Purification,application and current market trend of natural graphite:A review

Graphite has a stacked planar sp_2-hybridized C_6 ring structure, displaying a polymorphism with rhombohedral, hexagonal, and turbostratic. Based on its structure-property relationship, it affords a variety of technologically innovative applications or performances in industries, such as lithium-ion batteries, fuel cells, two dimensional graphene, water purification, electronics, fiber optics, spintronics, refractories,electrical products, electric vehicles, etc. The monetary value of graphite depends largely on carbon content and flake size. However, the physical separation of graphite from its ore body is known to be very expensive, energy intensive and time-consuming. Hence, this study extensively describes a current purification method for producing high-quality graphite material with impurities reaching about 10–100 mg/kg, attracting a lot of end users. It also describes the potential applications of graphite materials and identifies the future scope of a new market, depending on material purity. Finally, the current and future graphite-mining countries are investigated in details.     

Preparation and H2O2 oxidation of extract

Tongting coal (TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone (CS₂/NMP) mixed solvents to afford brown particles of extract, which was characterized with proximate analyzer, transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectrometer. The results show that the nanometer particles of extract, which were free of ash, are superfine and super-clean with tract content of 0.02% A_d and particles size of about 100–150 nm. TTC and extract were then subject to oxidation with H₂O₂ and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer (GC/MS). The results show that extract is more reactive with H₂O₂ in comparison to TTC and richer in oxygen-containing species including phenols, alcohols, ethers, esters, carboxylic acids and anhydrides.     

Compression sensibility of magnetic-concentrated fly ash mortar under uniaxial loading

The electrical conductivity, compression sensibility, workability and cost are factors that affect the application of conductive smart materials in civil structures. Consequently, the resistance and compression sensibility of magnetic-concentrated fly ash (MCFA) mortar were investigated using two electrode method, and the difference of compression sensibility between MCFA mortar and carbon fiber reinforced cement (CFRC) under uniaxial loading was studied. Factors affecting the compression sensibility of MCFA mortar, such as MCFA content, loading rate and stress cycles, were analyzed. Results show that fly ash with high content of Fe3O4 can be used to prepare conductive mortar since Fe3O4 is a kind of nonstoichiometric oxide and usually acts as semiconductor. MCFA mortar exhibits the same electrical conductivity to that of CFRC when the content of MCFA is more than 40% by weight of sample. The compression sensibility of mortar is improved with the increase of MCFA content and loading rate. The compression sensibility of MCFA mortar is reversible with the circling of loading. Results show that the application of MCFA in concrete not only provides excellent performances of electrical-functionality and workability, but also reduces the cost of conductive concrete.     

微波敏化强化芬顿试剂催化氧化NO机理研究

微波结合活性炭的微波敏化方式可大幅提高Fenton试剂氧化能力,为研究产物的生成路径及微波、活性炭、H2O2之间的关联性,自制不同孔隙材料及不同Fe含量的碳材料,采用多组对照实验验证产物O2、CO、NO2的可能生成路径及微波、活性炭的作用,最终得到微波敏化下的芬顿试剂催化氧化NO的反应机理.结果表明:采用活性炭加微波的敏化方式后,NO脱除效率可从33.1%提高至46.3%,O2生成量从6.9%增加到18.6%,同时伴随着体积分数68×10-6的CO生成; O2可通过活性炭的吸附作用及Fe2+的催化作用产生; C及NO只能被芬顿反应过程中生成的·OH、HO2·氧化成CO及NO2;微波可强化体系内所有可发生反应,活性炭能进一步提高微波敏化的前提是发达的孔隙,同时活性炭中存在的部分Fe元素参与到了芬顿反应.     

Forming regularity and relation between composition and property of B2O3-BaO-ZnO glass

B2O3-BaO-ZnO glass was prepared by using conventional melt quenching technology. The forming regularity and the relationship between the composition and the property of B2O3-BaO-ZnO glass were investigated. The results show that the composition range for forming B2O3-BaO-ZnO glass is very wide, but the content of B2O3 has a limit within mole fraction of 25%-75%. When the content of B2O3 is over the limit, the melt will be divided into two phases with different compositions and structures, whereas too low content of B2O3 will result in the crystallization of the melt during the cooling process. The thermal expansion coefficient, the transition temperature and the resistivity of the glass at room temperature are (5-10)×10-6 ℃-1, 480-620 ℃ and (1.5-3.0)×1010 Ω·m, respectively.     

Assessment of pH-responsive nanoparticles performance on laboratory column flotation cell applying a real ore feed

Nanoparticles(NPs) can promote the column flotation process in mining industry. Nanoparticles' effects on column flotation process(copper recovery, grade and flotation rate constant) are assessed in Sarcheshmeh Copper Complex, Iran, through response surface methodology(RSM) optimization technique. The c-Al_2O_3, a-Fe_2O_3, SiO_2, and TiO_2 nanoparticles are selected for these experiments. A flotation rate constant is chosen as a response to assess the effect of nanoparticles on flotation in its kinetic sense.The process p H and nanoparticle dosage are selected as the influential parameters. Results obtained from RSM indicated that the maximum percentage of Cu recovery and grade is obtained at p H of 12 and nanoparticle dosage of 6 kg/t, through a-Fe_2O_3 and c-Al_2O_3 nanoparticles, respectively. Applying nanoparticles in particular c-Al_2O_3 and a-Fe_2O_3 increases the Cu recovery by 8–10% together with the grade by 3–6% in a significant manner. It is revealed that nanoparticles could effectively be applied in enhancing the flotation performance.     

A novel collector RL for flotation of bauxite

The flotation properties of single minerals such as diaspore, kaolinite and pyrophllite in bauxites were investigated using RL as collector. The effects of regulators and unavoidable ions on flotation were studied. Based on the results of single minerals flotation, the separation experiments of mixed minerals and bauxite ore were carried out. The results of closed circuit test on the ore show that, using RL as collector, Na2CO3 and (NaPO3)6 as modifiers, the grade of Al2O3 and SiO2 are respectively 70.74% and 6.37% in concentrate(Al/Si 11.11 ), and the recovery of Al2O3 can reach 90.52 %.     

Glass-ceramics made from arc-melting slag of waste incineration fly ash

Grate fly ash and fluidized bed fly ash mixed with glass cullet additive respectively were melted in the electronic arc-furnace. The product, arc-melting slag, was further treated by crushing, pressing and heat treatment in order to make the glass-ceramics. The crystallization behaviors of the produced glass-ceramics were examined by differential thermal analysis (DTA), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Results show that main crystalline phase of the glass-ceramics from grate fly ash is wollastonite (CaSiO₃) with small amount of diopside (Ca(Mg,Al)(Si,Al)₂O₆), and that from fluidized bed fly ash is diopside (Ca(Mg,Al)(Si,Al)₂O₆). It is found that the glass-ceramics sintered at 850 °C and 1 000 °C from grate fly ash and fluidized bed fly ash respectively have the optimal physical, mechanical and chemical characteristics. Glass-ceramics samples, produced from incinerator fly ash with desirable properties and the low leaching concentration of heavy metals, can be the substitute of nature materials such as marble, granite and porcelain tiles.     

Electrical conductivity of （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts

The effects of contents of AlF3 and Al2O3, and temperature on electrical conductivity of （Na3AlF6-40%K3AlF6）- AlF3-Al2O3 were studied by continuously varying cell censtant （CVCC） technique. The results show that the conductivities of melts increase with the increase of temperature, but by different extents. Every increasing 10 ℃ results in an increase of 1.85 × 10^-2, 1.86× 10^-2, 1.89 × 10^-2 and 2.20 × 10^-2 S/cm in conductivity for the （Na3AlF6-40%K3AlF6）-AlF3 melts containing 0%, 20%, 24%, and 30% AlF3, respectively. An increase of every 10 ℃ in temperature results an increase about 1.89× 10^-2, 1.94 × 10^-2, 1.95 × 10^-2, 1.99× 10^-2 and 2.10× 10^-2 S/cm for （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts containing 0%, 1%, 2%, 3% and 4% Al2O3, respectively. The activation energy of conductance was calculated based on Arrhenius equation. Every increasing 1% of AlF3 results in a decrease of 0.019 and 0.020 S/cm in conductivity for （Na3AlF6-40%K3AlF6）-AlF3 melts at 900 and 1 000 ℃, respectively. Every increase of 1% Al2O3 results in a decrease of 0.07 S/cm in conductivity for （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts. The activation energy of conductance increases with the increase in content of AlF3 and Al2O3.     

碳源对反硝化脱硫工艺碳氮硫同步脱除效果的影响

针对碳源对反硝化脱硫工艺运行效能影响不明问题,实验采用UASB反应器,考查两种不同碳源(乙酸钠和苯酚)条件下反硝化脱硫工艺碳氮硫去除效果及单质硫累积率,在此基础上,通过批次试验进一步探究碳氮硫降解及转化规律.结果表明:乙酸钠为碳源,HRT为2.5~10 h,NO_3~--N、S~(2-)和Ac~--C去除率分别保持在93%、90%和99%以上,单质硫积累率稳定在41%以上;而苯酚为碳源,HRT为10 h,NO_3~--N、S~(2-)和C_6H_5O~--C去除率分别达67%、85%和50%,但硫化物均转化为硫酸盐,无单质硫累积.批次试验表明,乙酸钠为碳源时,S~(2-)氧化速率(qS~(2-))乙酸盐氧化速率(qAcetate)S~0的氧化速率(q_S~0);而苯酚为碳源时,S~(2-)氧化速率(qS~(2-))S0的氧化速率(q_S~0)苯酚氧化速率(qPhenol),从而使得硫化物的氧化产物有所差异.     

A new technology for processing niobite ore found in Jiangxi province

A new process is proposed for refining niobite ore that is found in Jiangxi province of China. Niobite, also known as columbite or niobite–tantalite, is a mineral that contains tantalum and niobium. The separation process includes two-stage grinding, gravity concentration, magnetic separation, and flotation. The tantalum/niobium concentrate obtained had a grade of Ta₂O₅ 18.28%, Nb₂O₅ 41.62% at a recovery rate of Ta₂O₅ 49.08%, Nb₂O₅ 70.77%. Other minerals occurring along with the niobite, such as zinnwaldite, feldspar, and quartz, were also recovered to comprehensively utilize this ore.     

高炉喷补料抗CO侵蚀能力初步研究

通过实验研究了高炉喷补料中Fe     

Synthesis and Characterization of LiCoxMn2-xO4 Cathode Materials

LiCoxMn2.04 cathode materials for lithium ion batteries were synthesized by mechanical activation-solid state reaction at 750 ℃ for 24 h in air atmosphere, and their crystal structure, morphology, element composition and electrochemical performance were characterized with XRD, SEM, ICP-AES and charge-discharge test. The experimental results show that all samples have a single spinel structure, well formed crystal shape and uniformly particle size distribution. The lattice parameters of LiCo Mn2-xO4 decrease and the average oxidation states of manganese ions increase with an increase in Co content. Compared with pure LiMn2O4, the LiCo Mn2xO4 （x=0.03-0.12） samples show a lower special capacity, but their cycling life are improved. The capacity loss of LiCo009Mn191O4 and LiCo0.1Mn1.88O4 is only 1.85% and 0.95%, respectively, after the 20th cycle. The improvement of the cycle performance is attributed to the substitution of Co at the Mn sites in the spinel structure, which suppresses the Jahn-Teller distortion and improves the structural stability.     

Preparation and structure characteristics of nano-Bi2O3 powders with mixed crystal structure

The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi(NO3)3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi(NO3)3 reacts at 90℃ for 2 h, the Bi203 powders with 60 nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi^3 to O^2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.