水煤浆制备过程中浆体抗搅拌性能的研究

选用两种不同类型的分散剂，考察了１１种不同变质程度煤在高浓度煤浆制备过程中的浆体抗搅拌性能。发现高浓度煤浆制备对应的最佳搅拌强度不仅与分散剂的种类有关，而且取决于煤的变质程度。浆体抗搅拌性能随制浆用煤的变质程度的提高而增强，从而使较高变质程度煤的高浓度煤浆制备需在较高的搅拌强度下进行，才能最大限度地提高煤的成浆性。相关分析表明，煤表面分布的羧基、酚羟基等亲水性基团对浆体抗搅拌性会产生重要影响，煤表面此类基团的含量较高或吸水性较强时可使高浓度煤浆制备的最佳搅拌强度大幅度降低。     

Advances in ultrasonic slurry graphite furnace atomic absorption spectrometry

Summary Ultrasonic slurry graphite furnace atomic absorption spectrometry is a useful technique for automated direct analysis of solids. The effectiveness of ultrasonic agitation for mixing samples is demonstrated. This analytical approach is evaluated to identify sources of imprecision. Strategies for optimizing slurry preparations are discussed, focusing on particle size, density, analyte partitioning, and sampling limitations. Finally, a teflon bead method is presented for grinding biological and botanical samples. An optimized general approach for ultrasonic slurry sampling is presented.Presented at the 5th International Colloquium on Solid Sampling with Atomic Spectroscopy, May 18–20, 1992; Geel, Belgium. Papers edited by R. F. M. Herber, Amsterdam.     

Enhancing plasma peptide MALDI-TOF-MS profiling by mesoporous silica assisted crystallization

Promising profiling techniques based on new material/solid phase extraction for capturing “molecular signatures” from body fluids are being coupled to MALDI-TOF-MS. Sample preparation significantly influences spectrum quality in this ionization method. Mesoporous silica beads (MSB), by the means of nano-sized porous channels with high surface area, enable harvesting of peptides from plasma and serum excluding large size proteins. We have investigated the morphology of a sample slurry, developed as a new tool for plasma peptides enrichment based on mesoporous materials. Our study highlights a correlation between crystals morphology and enhanced performances in MALDI-TOF-MS analysis. This is the first report which correlates the increase in signal intensity with crystal formation in samples preparations which make use of various kinds of slurries for the analysis of samples clinically relevant like human plasma.     

浆态床用CuO/ZrO2催化剂的完全液相法合成及其对CO加氢的催化性能

 利用完全液相法制备了CuO/ZrO2浆状催化剂,通过X射线衍射、氮气吸附和程序升温还原等方法对催化剂的结构和织构性质进行了研究,并考察了CuO/ZrO2催化剂上CO加氢反应的性能. 结果表明,本方法制备的CuO/ZrO2浆状催化剂具有与传统方法制备的固体催化剂相似的相结构; 利用共沸蒸馏法进行表面处理后, CuO/ZrO2催化剂分散均匀且易于还原; CuO/ZrO2浆状催化剂用于CO加氢反应时,不需另外添加甲醇脱水剂就可以直接合成二甲醚,在473 K时CuO/ZrO2对二甲醚的选择性达到92.1%, 并且在15 d的反应中催化剂呈现出良好的稳定性.     

外加无机电解质对煤浆性质调控作用的研究

考察了数种无机电解质对煤浆分散体系流变特性的影响。结果发现，煤浆的流变特性不仅与电解质种类有关，还取决于煤质特征。某些煤适，适量的无机电解质可使浆体的屈报胀塑料转化为屈服假塑性。     

Evaluation of Platanus occidentalis and Pinus sylvestris as bioindicators for lead and cadmium by slurry sampling-electrothermal atomic absorption spectrometry

Two higher plants (Platanus occidentalis and Pinus sylvestris) were used as bioindicators for assessment of contamination by Pb and Cd in an urban and industrialized area. Both toxic metals in plant tissue were determined by transverse-heated electrothermal atomic absorption spectrometry-longitudinal Zeeman background correction combined with automated ultrasonic slurry sampling. Twenty sampling points were established to observe a relationship between metal concentration in plant and traffic density. Screening optimization of variables influencing slurry preparations (sonication time, sonication power, and surfactant concentration) followed a fractional factorial design at 2 levels. No significant effects were observed in the interval of variables studied. Limits of detection of Pb and Cd in the plants were 0.28 and 0.025 microg/g (dry weight), respectively. Metal concentrations in the plants were in the range of 5-51 and 0.05-0.7 microg/g for Pb and Cd, respectively. Factor analysis to data of metal concentration in both plants, extractable metal content in soil, distance to traffic, and traffic density, showed a significant association between features such as concentration of Pb and Cd in leaves of P. occidentalis and traffic density, which accounted for the largest variance. Other features such as extractable metal contents in soil accounted for lesser variance, meaning that soils in the area investigated were less suitable than plants for monitoring metal pollution caused by vehicular traffic.     

煤浆浓度和颗粒分布对煤浆黏度预测的影响

采用神华煤制备煤浆,分析了颗粒粒径比λ和小颗粒体积分数ξ对双峰分布浆体黏度的影响,根据浆体黏度的关联式预测了煤浆的黏度并且与实验结果进行了比较。结果表明,采用双峰分布的颗粒制浆可以有效地降低浆体的黏度,同时可以获得较大的浆体体积分数 。在相同体积分数下,随着颗粒粒径比λ的增加,浆体的黏度迅速下降。当小颗粒体积分数ξ_dp1为35%时,浆体的黏度最小。采用Ouchiyama模型计算浆体的最大体积分数Φ_m与实验值较为吻合,而浆体的本质黏度[μ]基本保持不变。考虑λ和小颗粒体积分数ξ对双峰分布浆体的最大体积分数Φ_m的影响,可以采用单峰分布浆体的黏度关联式预测双峰分布浆体的黏度。     

蓝藻与神府煤共成浆性的研究

考察了预处理方法对含水蓝藻表观黏度的影响,以及蓝藻对神府煤浆成浆浓度、流变性和静态稳定性的影响。结果表明,采用添加化学药剂、高速搅拌、加热等方法对含水蓝藻进行预处理,可以使表观黏度从72mPa·s降低到21.8mPa·s(剪切速率100s^-1)。蓝藻结构受到破坏是表观黏度降低的主要原因。含水蓝藻表观黏度的降低有利于蓝藻煤浆成浆浓度的提高。当添加水质量与含水蓝藻质量比为1∶1时,蓝藻煤浆的成浆浓度达到60%。蓝藻的加入提高了神府煤浆的稳定性,使稳定性从4h提高到72h以上。蓝藻煤浆为假塑性流体,剪切变稀。     

半干法烟气脱硫喷嘴的雾化特性研究

利用FAM型衍射式激光测粒仪，对双流体石灰浆液雾化喷嘴的雾化特性进行了试验研究，得到了预测雾滴平均粒径的经验公式，分析了气耗率、石灰浆液浓度等参数对雾化粒径分布和雾化角的影响规律。结果表明，气液质量比增大，浆液液滴平均直径(SMD)减小；浆液浓度增加，液滴平均直径增加。气液质量比在0.05～0.3的范围内可获得良好的雾化效果，雾化粒径一般在20 μm～100 μm。喷嘴的雾化角较小，一般在20°～25°之间。气液质量比增加，雾化角减小；而石灰浆浓度对雾化角影响较小。     

Abrasive properties of nano silica particles prepared by a sol–gel method for polishing silicon wafers

Abrasive properties of cocoon shaped silica particles fabricated by a sol–gel method have been studied. Since silicon wafers are polished with slurry by the mechanism of Chemical Mechanical Polishing, polishing rates may depend on various chemical and mechanical factors, such as particle concentration in slurry, slurry pH and kinds of basic compounds for controlling the slurry pH. The silicon wafer was polished by slurry continuously fed on a pad, and the polishing rate was estimated as a weight loss of the wafer. For studying the effects of the various factors on the rate, the slurries were prepared by adding the silica particles, basic compounds or salts, and the polishing rates of the slurry were measured. The effects of the various factors were made clear as follows: For the effect of particle concentration, the rates increased with increasing of the concentrations up to 1.0 wt.%. And for the effect of the slurry pH, slurries added basic compounds, such as KOH, NaOH, ammonia, were tested, and it was found that increasing of the slurry pH brought increases of the polishing rates. KOH-containing slurry of pH 13.2 had the fastest rate, 3.6 times as fast as the standard slurry with pH 9.4. For the effect of the adding of salts, it was indicated that the salts, such as KCl, NaCl, NH₄Cl, NaNO₃ and K₂SO₄ increased the polishing rates, and that KCl-containing slurry of 0.36 mol/l had the highest polishing rate, 3.4 times as fast as that of the standard slurry containing no salts.     

超声波强化水煤浆制备方法的研究

本文研究用超声波技术强化高浓度水煤浆的制备方法，选择适当的处理条件和设备，经超声波处理的水煤浆，煤粉级配明显向细的方向转化，不仅表观粘度大幅度降低，而且浆体静态稳定性和流变特性也得以显著改善。     

Slurry sampling techniques for the determination of lead in Bangladeshi fish samples by electrothermal atomic absorption spectrometry with a metal tube atomizer

Ultrasonic slurry sampling electrothermal atomic absorption spectrometry with a metal tube atomizer has been applied to the determination of lead in Bangladeshi fish samples. The slurry sampling conditions, such as slurry stabilizing agent, slurry concentration, pyrolysis temperature for the slurried fish samples, particle size and ultrasonic agitation time, were optimized for electrothermal atomic absorption spectrometry with the Mo tube atomizer. Thiourea was used as the chemical modifier for the interference of matrix elements. The detection limit was 53 fg (3S/N). The determined amount of lead in Bangladeshi fish samples was consistent with those measured in the dissolved acid-digested samples. The advantages of the proposed methods are easy calibration, simplicity, low cost and rapid analysis.     

Application of the slurry technique to biological materials: a survey of literature

Summary The literature on the application of the slurry technique to biological materials is reviewed. It is obvious from the various applications that the most frequently employed atomization method for slurry analysis in biological materials is electrothermal atomization using either graphite tube or platform atomizers. The slurry technique is particularly useful when certified reference materials are not available and when the standard addition method is to be avoided. The literature survey revealed that this technique compares favourably with other methods for the determination of trace metals in biological materials.     

Direct determination of impurities in high purity silicon carbide by inductively coupled plasma optical emission spectrometry using slurry nebulization technique

A novel method for the determination of Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni and Ti in high purity silicon carbide (SiC) using slurry introduction axial viewed inductively coupled plasma optical emission spectrometry (ICP-OES) was described. The various sizes of SiC slurry were dispersed by adding dispersant polyethylene imine (PEI). The stability of slurry was characterized by zeta potential measurement, SEM observation and signal stability testing. The optimal concentration of PEI was found to be 0.5 wt% for the SiC slurry. Analytical results of sub-μm size SiC by the slurry introduction were in good accordance with those by the alkaline fusion method which verified that determination could be calibrated by aqueous standards. For μm size SiC, results of most elements have a negative deviation and should be calibrated by the Certified Reference Material slurry. Owing to a rather low contamination in the sample preparation and stability of the slurry, the limits of detection (LODs), which are in the range of 40-2000 ng g⁻¹, superior to those of the conventional nebulization technique by ICP-OES or ICP-MS.     

Strategies for Optimal Chemical Mechanical Polishing (CMP) Slurry Design

Abstract

Chemical mechanical polishing (CMP) has become the preferred route for achieving wafer‐level global planarization in microelectronics device manufacturing. However, the micro‐ to molecular‐level mechanisms that control its performance and optimization are not well understood. In CMP, complex slurry chemistries react with the first few atomic layers on the wafer surfaces forming a chemically modified film. This film is subsequently mechanically abraded by nanosized slurry particles to achieve local and global planarity for multi‐level metalization. For optimal CMP performance, high material removal rates with minimal surface defectivity are required. This can be achieved by controlling the extent of interparticle and particle–substrate interactions, which are facilitated through the manipulation of the slurry composition, solution chemistry, as well as operational parameters. Interparticle interactions must be engineered to maintain slurry stability to minimize the number and extent of surface defects during polishing while maintaining adequate removal rates. The fundamental considerations, which are necessary for the development of high performance CMP slurries, are discussed in this article through model silica CMP systems.     

Evaluation of direct analysis in real time mass spectrometry for onsite monitoring of batch slurry reactions

Batch slurry reactions are widely used in the industrial manufacturing of chemicals, pharmaceuticals, petrochemicals and polymers. However, onsite monitoring of batch slurry reactions is still not feasible in production plants due to the challenge in analyzing heterogeneous samples without complicated sample preparation procedures. In this study, direct analysis in real time mass spectrometry (DART-MS) has been evaluated for the onsite monitoring of a model batch slurry reaction. The results suggested that automation of the sampling process of DART-MS is important to achieve quantitative results. With a sampling technique of manual sample deposition on melting point capillaries followed by automatic sample introduction across the helium beam, relative standard deviation (RSD) of the protonated molecule signals from the reaction product of the model batch slurry reaction ranged from 6 to 30%. This RSD range is improved greatly over a sampling technique of manual sample deposition followed by manual sample introduction where the RSDs are up to 110%. Furthermore, with the semi-automated sampling approach, semi-quantitative analysis of slurry samples has been achieved. Better quantification is expected with a fully automated sampling approach.     

原煤和黑液水煤浆燃烧特性的热分析对比研究

在热天平上进行黑液水煤浆和原煤的燃烧、热解实验,得到不同升温速率下的燃烧、热解特性曲线和碳转化率特征曲线。试验结果表明,黑液水煤浆中的钠及其化合物在燃烧过程中催化作用明显,并且黑液中有机物成分对燃烧起到一定促进作用。在20 ℃/min升温速率下黑液水煤浆和原煤的燃烧活化能分别为12.98 kJ/mol和106.59 kJ/mol,反映出黑液水煤浆比原煤有更好的着火特性。     

An experimental study on the rheological properties of aqueous ceria dispersions

The rheological properties of aqueous ceria dispersions are studied experimentally. In particular, the effects of particle concentration, temperature, pH, and ionic strength are discussed. If the volume fraction is below 2%, ceria slurry exhibits Newtonian behavior, and for higher volume fractions, shear-thinning behavior is observed. The effect of temperature on the behavior of ceria slurry is found to be pH-dependent. If pHIEP, the viscosity slightly increases with increased temperature. A shift of IEP to a higher value of pH was observed for ionic strength, even for indifferent electrolytes. The influence of pH on the rheological properties of ceria slurry decreases if the ionic strength is high. The pH at which viscosity and yield stress are maximum coincide with IEP only for low ionic strengths. The slopes of acidic and basic branches of viscosity against pH and yield stress against pH curves are not symmetrical at high ionic strength, and the alkaline branch deviates significantly from Hunter's theory.     

Role of Low Molecular Weight Polymers on the Dynamics of Silicon Anodes During Casting

This work probes the slurry architecture of a high silicon content electrode slurry with and without low molecular weight polymeric dispersants as a function of shear rate to mimic electrode casting conditions for poly(acrylic acid) (PAA) and lithium neutralized poly(acrylic acid) (LiPAA) based electrodes. Rheology coupled ultra-small angle neutron scattering (rheo-USANS) was used to examine the aggregation and agglomeration behavior of each slurry as well as the overall shape of the aggregates. The addition of dispersant has opposing effects on slurries made with PAA or LiPAA binder. With a dispersant, there are fewer aggregates and agglomerates in the PAA based silicon slurries, while LiPAA based silicon slurries become orders of magnitude more aggregated and agglomerated at all shear rates. The reorganization of the PAA and LiPAA binder in the presence of dispersant leads to a more homogeneous slurry and a more heterogeneous slurry, respectively. This reorganization ripples through to the cast electrode architecture and is reflected in the electrochemical cycling of these electrodes.     

黑液水煤浆主要矿物元素在炉内的迁移和沉积行为研究

为了研究黑液水煤浆的灰沉积机理，采用沿烟气行程从实验炉不同部位抽取空间灰粒和提取相应位置炉壁灰渣样相结合的方法，并与常规水煤浆相对比，研究了各主要矿物元素（Na、K、Si、Al、Fe、Ca）在烟气流中的迁移趋势和沉积特性。并且通过X射线衍射（XRD）和扫描电镜（SEM）等分析从微观角度进行了验证。结果表明，与常规水煤浆不同的是，Na、Si、Al的迁移和沉积是引起黑液水煤浆沾污结渣的主要矿物元素，灰沉积物中主要包括无水芒硝、霞石等低熔融温度富Na物相，而Fe的沉积是次要因素。