新型有机黏结剂HC用于制备冷压球团的研究

采用新型有机黏结剂(HC)代替膨润土制备冷压球团的方法,得到高冶金性能的入炉原料.随着HC和膨润土用量(质量分数,下同)的增加,铁矿球团和含碳球团生球的抗压强度均呈逐渐升高的趋势,当黏结剂用量为1.5％时,抗压强度分别为5264,2012 N/个;生球落下强度随着HC用量的增加而增加,但随着膨润土用量的增加变化趋势不明...     

A novel CO and C3H8 sensor made of CuSb2O6 nanoparticles

Trirutile-type CuSb₂O₆ nanoparticles were synthesized by a simple and economical route, starting from copper nitrate, antimony chloride, ethylenediamine, and ethyl alcohol as solvent. The latter was evaporated by microwave radiation at 140 W. The precursor material was calcined at 200, 300, 400, 500, and 600 °C, and analyzed by powder XRD. The oxide phase was obtained at the last calcination step (600 °C), whose powders were analyzed by field-emission scanning electron (FE-SEM) and transmission electron (TEM) microscopies. Microrods, hexagonal microplates, and nanoparticles with an average size of ~ 51.2 nm were observed. A forbidden bandwidth of 3.41 eV was detected for the direct transition with UV–vis. Tests were carried out on pellets made of the powders in carbon monoxide (CO) and propane (C₃H₈) atmospheres at different concentrations and operating temperatures, obtaining high response at 300 ppm of CO and 500 ppm of C₃H₈, both at 300 °C.     

High-throughput automated dissolution method applicable for a wide dose range of controlled release pellets

The aim of the present study was to demonstrate the application of an automated high-throughput (HT) dissolution method as a useful screening tool for characterization of controlled release pellets in the formulation development phase. Five controlled release pellet formulations with drug substances exhibiting high or low solubility were chosen to investigate the correlation of the automated HT dissolution method with the conventional dissolution testing. Overall, excellent correlations (R^2?>^?0.96) between the HT and the conventional dissolution method were obtained. In one case the initial unsatisfactory correlation (R^2?=^?0.84) and poor method agreement (SD?=?12.5) was improved by optimizing the HT dissolution method with design of experiment approach. Here in comparison to initial experimental HT dissolution settings, increased amount of pellets (25% of the capsule filling mass), lower temperature (22?°C) and no shaking resulted in significantly better correlation (R^2?=^?0.97) and method agreement (SD?=?5.3). These results show that such optimization is valuable for the development of HT dissolution methods. In conclusion, the high correlation of dissolution profiles obtained from the conventional and the automated HT dissolution method combined with low within-sample and measurement system variability, justifies the utilization of the automated HT dissolution method during development phase of controlled release pellets.     

脱硫石膏料球的分解

为研究脱硫石膏在成球状态下的分解特性,根据石膏分解气固反应和固固反应机制,探索脱硫石膏料球分解反应的影响因素及其影响规律。研究结果表明:脱硫石膏料球很难在弱还原性气氛条件下分解;在掺入石油焦作为固体还原剂后,脱硫石膏能够较好地实现分解。正交实验结果表明:掺入石油焦的脱硫石膏料球较优的分解条件为:分解温度1 200℃、分解时间30 min、碳硫摩尔比n(C)/n(S)为1.0、料球粒径为5~7 mm。     

粉末压片制样—X射线荧光光谱法测定钼铁中的钼

本文介绍了粉末压片制样-X射线荧光光谱法对钼铁中钼含量测定的检测方法。文中采用钼铁样品与微晶纤维素、硬脂酸按一定的质量比混匀并细磨后采用硼酸镶边-衬底技术进行样品制备。选用生产用普通系列样品绘制标准工作曲线,在X射线荧光光谱仪上测定钼的含量。测量结果与钼酸铅重量法分析结果相符。     

Reduction kinetics of carbon containing pellets made from metallurgical dust

Abstract

Reduction experiments of carbon containing pellets made from metallurgical dust were conducted under a weak oxidising atmosphere in the temperature range of 1348–1573 K. Analysis of kinetics and the reduction mechanism revealed that the rate determining step of the reduction of the pellets is the interfacial or local reaction with the activation energy 111·66 kJ mol^?1. The reduction rate can be expressed by the McKewan equation 1?(1?R)^1/3?=?kt. In addition, temperature is an important factor influencing the reaction rate as dezincification and metallisation increase with the increased temperature. The amount of dezincification and metallisation could be up to 97·8 and 79·9% respectively at 1573 K compared to a minimum of 75·3 and 60·2% at 1348 K.     

Studies on the Reduction–Swelling Behaviors of Hematite Iron Ore Pellets with Noncoking Coal

Studies on the reduction and swelling behaviors of fired pellets, made by mixing hematite iron ore fines of ?100, ?18 + 25, and ?10 + 16 mesh sizes in different proportions, were carried out with low-grade coal in the temperature range of 850–1000°C with an aim to promote the massive utilization of fines in ironmaking. The rate of reduction in all the fired iron ore pellets increased markedly with an increase in temperature up to 1000°C and it was more intense in the first 15-min soak time. Relatively higher reduction rates and swellings/shrinkage were observed in the pellets made by the addition of larger size (+100 mesh) particles in the matrix of ?100 mesh size fines. In general, highest swelling was observed in the fired pellets at a reduction temperature of 850°C, followed by a decrease at 900°C. At both these temperatures, the percentage of swelling increased with reduction time up to the range studied (120 min). The fired pellets reduced at temperatures of 950°C and 1000°C, showed shrinkage, and the extent of this shrinkage increased with increase in exposure time at 950°C. The percentage swelling/shrinkage in the fired pellets was found to be related to their crushing strengths and porosities.     

Dimensional Changes in Irradiated (Th,U)O2

Effects of irradiation on the dimension and microstructure in (Th,U)O₂ pellets were examined by measurements of lattice parameter and bulk density changes, and observations of pore structures. The concentrations of fission-induced defects and the damage volume were estimated by a simple model. Both macroscopic and microscopic dimensional changes were found to increase initially with fission dose and then fall off. The difference between macroscopic and microscopic ingrowths increased with dose, suggesting that fission-induced interstitials would cluster or go to sinks and the concentration of vacancies would be in excess of that of interstititials. The damage volume for vacancies was estimated to be about 1x10^?22m³·fiss.^?1, and almost agreed with that for fission Xe release. Observations of the pore structure indicated that the volume fraction of pores smaller than 2–3 μm decreases with irradiation and the distribution of pore size shifts toward the larger side.     

Evaluation Methods of Resonance Absorption for System with Pellet Surrounded by Fuel Solution

Abstract

The reaction cross sections of ²⁷Al(n, p)²⁷Mg, ²⁷Al(n, a)²⁴Na, ⁵⁶Fe(n, p)⁵⁶Mn, ⁹⁰Zr(n, 2n)^89m+gZr and ⁹³Nb(n, 2n)^92mNb have been measured by the activation method in an energy range of 13.3–14.9 MeV using the intense D-T neutron source, FNS. Absolute flux was determined by the associated α-particle counting method incorporated with neutron spectra obtained from both a Monte Carlo calculation and a time-of-flight measurement. Corrections were extensively performed not only for the neutron flux determination, but also for the low energy neutron contribution to the reaction rates. The present data were compared with comprehensive evaluations as well as recent experimental data. The measured cross sections of ²⁷Al(n, a)²⁴Na, ⁵⁶Fe(n, p)⁵⁶Mn and ⁹⁰Zr(n, 2n)^89m+gZr are generally in good agreement within experimental errors with the values in both the JENDL Dosimetry File and IRDF-90. It is also shown that there are the overestimation of the cross sections for ⁹³Nb(n, 2n)^92mNb in the JENDL Dosimetry File, and the over- estimation and underestimation of the cross section for ²⁷Al(n, p)²⁷Mg in the JENDL Dosimetry File and IRDF-90, respectively.     

Solidification of “Cement-Glass”

Cement-glass, which is a mixture of sodium silicate (kNa₂O·mSiO₂nH₂O), silicon phosphate (P₂O₅·2SiO₂) and cement, was developed to solidify radioactive waste pellets in containers. The optimum molar ratio of Si(OH)₄, NaOH and P₂O₅2SiO₂ was found to be 2:2:1, based on compressive strength measurement of solidified samples. The compressive strength of solidified sodium silicate with silicon phosphate was increased when the amount of solidified SiO₂ per unit volume was increased by reducing the water content. Cement-glass had a higher Cs distribution factor than ordinary Portland cement.