Characterization of Lunar Dust for Toxicological Studies. I: Particle Size Distribution

The particle size distribution (PSD) of lunar dust, the <20?μm portion of the regolith, was determined as an initial step in the study of the possible toxicological effects it may have on the human respiratory and pulmonary systems. Utilizing scanning electron microscopy, PSDs were determined for Apollo 11 (10084) and 17 (70051) dust samples, as well as lunar dust simulant JSC-1Avf. The novel methodology employed is described in detail. All measured PSDs feature a log-normal distribution having a single mode in a range 100–300?nm for lunar dust samples, but the lunar simulant has a mode at ～ 600?nm.     

新冶钢电弧炉粉尘精细还原实验研究

对烘干后的电弧炉干粉尘进行基础特性研究,包括化学成分、XRD(X-ray diffraction)检测、粒度分布。根据铁氧化物、锌氧化物的还原热力学原理,提出了"电弧炉粉尘精细还原"的概念。探讨温度(910～1 010℃)和还原时间(2～4h)对电弧炉粉尘金属化率和脱锌率的影响,并利用SPSS(Statistical Product and Service Solutions)软件对实验结果进行方差分析和相关性分析结果表明,电弧炉粉尘TFe含量为47.26%,Zn含量为8.32%;在910～1010℃,使用纯H2对电弧炉粉尘进行精细还原,能实现铁氧化物和锌氧化物分别向MFe和Zn的转变,金属化率和脱锌率分别达到95%、98%左右;同时电弧炉粉尘精细还原的产物未有烧结现象发生。     

炼钢转炉尘泥球团应用研究

为了解转炉尘泥球团应用于转炉中的冶炼性能,进行了生产性对比实验。试验表明：应用尘泥球团作为化渣剂可加快初期炉渣的形成,明显提高转炉炉渣的去磷能力,回收一定量的铁元素,降低石灰和氧气消耗。     

密相输送在金隆烟灰改造中的应用

结合金隆铜业有限公司烟尘输送系统改造,介绍密相输送装置工作原理、控制方法、运行步骤以及一些故障的处理和改进措施。     

Toward an Improvement in the Identification of Bridge Deck Flutter Derivatives

This paper presents a short review of the state-of-the-art methods to identify bridge deck flutter derivatives and proposes a new algorithm to simultaneously extract the aeroelastic coefficients from free-vibration section-model tests, which is based on the improvement of the unifying least-squares (ULS) method and is therefore called modified unifying least-squares method. The advantages with respect to ULS are the faster and better convergence and the improvement in accuracy due to the introduction of weighting factors in the unifying error function. The method has been validated through numerically simulated noisy signals and experimental heaving and pitching time histories for two different bridge deck cross sections: a single-box and a multiple-box girder section model. The analysis of the artificial signals shows that a few system parameters are very difficult to be identified due to the fact that the problem is strongly ill-conditioned. Nevertheless, all the diagonal and off-diagonal components of the stiffness and damping matrices which significantly contribute to the output of the system are correctly estimated. The improvement with respect to other methods is extensively discussed. For the wind-tunnel test cases the accuracy of the identification procedure is evaluated through the comparison between measured signals and those simulated through the estimated mechanical and aerodynamic system parameters with very satisfactory results. With respect to many previous attempts of validation, this approach clearly shows the degree of accuracy that can be expected from the identification algorithm. Finally, for the considered test cases the linear model which stands behind the method seems to be an acceptable approximation of the physics of the phenomenon.     

Evaluation of Dust Palliatives for Unpaved Roads in Arid Climates

An evaluation of commercial and experimental dust palliatives was conducted to determine their effectiveness for mitigating fugitive dust on roads in arid climates. Several types of chemicals were tested including polymer emulsions, lignosulfonates, chloride salts, synthetic fluids, an asphalt emulsion, a polysaccharide solution, a polyacrylamide, and a guar gum. Each product was placed in an individual test section at a rate of 3.8?L/m2 using an admix construction method (grade/spray/till/compact/spray). Fourteen test sections were constructed and observed at 30-day intervals to monitor product performance. Data from both stationary and mobile particle collectors were analyzed to determine the ability of each product to suppress dust for extended periods. Several products are recommended for use on roads in arid climates as a result of this evaluation.     

控制爆破在VS喉口除灰垢中的应用

简要介绍运用控制爆破技术对文氏管洗涤装置喉口所积灰垢进行彻底清除的实践经验与方法，并估算了所产生的经济效益．     

Estimating Hydraulic and Thermal Conductivities of Crushed Granite Using Porosity and Equivalent Particle Size

This paper presents an experimental study of the effect of porosity and particle size on the hydraulic conductivity and thermal conductivity of sand-sized crushed granite particles with diameters ranging from 0.08–10?mm. The results show that the hydraulic conductivity varies with particle size and porosity, but thermal conductivity varies primarily with porosity. Estimating methods found in the literature are used in an attempt to predict the measured hydraulic and thermal conductivities of the crushed granite materials. The results show that the hydraulic conductivity model of Chapuis generally yields accurate estimated values for d102n3/(1-n)2 larger than 0.01??mm2. Below this critical point, the estimating method progressively yields larger values of hydraulic conductivity. A new set of empirical parameters are proposed to extend the use of this method to crushed granite materials at low d102n3/(1-n)2 values. It is also shown that predicted thermal conductivity values obtained with the C?té and Konrad model agree well with the experimental data. Issues regarding the extension of the models to coarser materials are discussed.     

Feasibility of Air Classification in Dust Recycling in the Iron and Steel Industry

The potential of air classification of dusts from dry off‐gas cleaning for improved recycling of these dusts is investigated. By air classification, a dust can be separated into a coarse fraction and a fine fraction. Some components which are usually unwanted in recycled dust like alkali chlorides and Zn and Pb are often enriched in the fine dust fraction. Thus, air classification of dust before recycling will allow recycling of an increased amount of dust and, thereby reduce the amount of dust which has to be sent to landfill. The feasibility of such treatment is studied on the basis of estimated investment costs and operating costs. The main factors affecting the feasibility of such a treatment are the capacity of the unit, the cost of landfill of the respective dust, and the fraction of dust which can additionally be recycled after the treatment. The investigation of classification of BF dusts and sinter plant dust shows that economic operation can be reached under the assumed conditions at landfill costs above 35–60 EUR/t for BF dust and 90 EUR/t for sinter plant dry desulfurization and de‐dusting residue. The integration of air classification into EAF dust in‐plant recycling can be feasible, too.     

高炉粉尘造泡沫渣过程中FeO还原动力学的研究

为了循环利用高炉粉尘,研究了用宝山钢铁股份有限公司高炉粉尘与沥青焦粉混合后加入电弧炉造泡沫渣过程中FeO的还原动力学。结果表明,随粉尘加入量的增加和温度的升高,FeO的还原速率加快;用固体碳还原渣中FeO的反应为表观二级反应,其表观活化能为276kJ／mol;用固体碳还原渣中FeO的反应总速率由CO还原FeO的界面化学反应和炉渣的流动传质共同控制。     

电除尘器中粉尘粒子的力学行为分析

粉尘粒子在电除尘器中的力学行为直接影响电除尘器的振打清灰效果。为了提高电除尘器的收集效率，笔者利用电晕理论和固体接触理论深入研究粉尘粒子在电场中及在收尘极板上的力学行为。研究表明：库仑力、范德华力、交联力、静电引力及粉尘层间的电场力对粉尘粒子的力学行为有明显的影响，而粉尘粒子的比电阻在其中起了很重要的作用。     

Particle Image Velocimetry Measurements of the Mean Flow Characteristics in a Bubble Plume

A direct measurement method for the velocity field in multiphase flows using the particle image velocimetry (PIV) and particle tracking velocimetry (PTV) methods is developed to study the flow characteristics of an unbounded bubble plume in quiescent, unstratified ambient conditions. A single camera is used to obtain images containing both bubbles and fluid tracer particles. Using gray-scale thresholding, phase-separated images of the bubbles are produced, and bubble velocities are obtained from these images using the standard PTV method. Regular PIV is applied to the mixed fluid images, and bubble vectors are removed using a velocity threshold and vector median filter that is calibrated to the PTV result. From the separate velocity fields, the time-averaged flow characteristics of a bubble plume are studied. Gaussian velocity profiles match the entrained fluid velocity, and top-hat velocity profiles match the bubble velocity. Time-averaged values are also presented of velocity, plume width, entrained fluid volume flux, and void fraction as a function of height. From these data, the entrainment coefficient for the entrained ambient fluid is calculated and lies between 0.08 near the plume source and 0.05 in the upper reaches. The results for the entrainment coefficient, together with those from the literature, are correlated to a nondimensional velocity, given by the ratio of the bubble slip velocity us to a characteristic velocity in the plume (B/z)1/3, where B = kinematic buoyancy flux and z is the height above the source.     

Carbothermic Reduction of Zinc and Iron Oxides in Electric Arc Furnace Dust

The reduction of zinc and iron oxides from electric arc furnace dust(EAFD)by carbon was investigated at temperatures between 800and 1 300℃.The analytic technique employed includes chemical analysis,X-ray fluorescence spectroscopy(XRF),X-ray powder diffraction(XRD),scanning electron microscopy(SEM)equipped with X-ray energy dispersive spectrometry(EDS),and thermodynamic database FactSage 6.2.It was found that the reduction of zinc and iron oxides depends largely on Boudouad reaction.At 900 ℃,zinc exists in tested samples as ZnO,which is reduced in the temperature range of 1 000-1 100℃.At 1 100℃,99.11% of the zinc is evaporated.The metallization ratio of Fe is 79.19% at 1 300℃,as the content of Fe2+ is still 9.40%.A higher temperature is thus required for a higher reduction degree of Fe oxides by solid or gaseous carbon.     

回转窑还原焙烧锌冶炼污泥与烟尘回收研究

设计了处理能力为100t/d的回转窑,开展低品位锌冶炼废水处理污泥还原焙烧回收氧化锌烟尘的试验。结果表明,污泥含锌品位对回转窑挥发获得氧化锌烟尘的效果有显著影响;当污泥的锌品位为5.04%和8.34%时,表冷收尘系统回收烟尘含锌分别为19.4%和21.4%,对应的布袋收尘系统回收烟尘的含锌量高达50.2%和51.6%。水淬渣浸出液中重金属浓度均低于GB5085.3-2007危险废物的各项限值,可直接用于生产或堆存。     

电磁力场作用下凝固界面前沿颗粒迁移特性的理论模型

本文在前人对无外力场作用时颗粒在凝固界面前受力分析的基础上,地电磁力场作用下颗粒在凝固界面前沿的迁移特性进行了理论上的分析讨论,分别推导了一定电磁力作用下水平和垂直凝固界面前沿颗粒推斥／在没转变的临界凝固速度,以及一定凝固速度睛,水平和垂直凝固界面前沿颗粒推斥／吞油转变的临界电磁力。     

酸溶电感偶合等离子体原子发射光谱法测定地质样品中的钼

文章建立了ICP-AES法测定地质样品中钼的新方法。样品经过酸溶处理后,在5%硫酸介质中,采用ICP-AES法测定地质样品中钼,最优工作条件是RF功率为1 150W,雾化气压力为28Psi。对7个国标钼矿样品的分析显示该方法准确度高、简单、快速。经本法测定300多件地质样品与文献[1,2,7]所用方法比较,数据完全满足文献[9]的要求。该方法缩短了地质样品的检测周期。     

山东焦家金矿充填站降尘改造实践

针对望儿山矿区水泥砂仓下放口产尘量大、环境污染严重等问题,采用抽出式通风方法对水泥料仓进行除尘改造,即通过增加局扇通风的方式,将下料口产生的粉尘抽至地表,防止粉尘超标,改善井下作业环境.通过改造除尘系统,矿区粉尘量显著减少,为工作人员提供了良好的工作环境,值得类似矿山借鉴.     

Decomposition,Reduction and Dissolution Mechanism of Calcium Sulfate in Iron Oxide Dust Pellet

Iron oxide dust generated during oxygen blowing in the BOF process contains a high content of iron. This iron oxide dust can be used as a material of iron source in the BOF slag reduction process or as de‐siliconisation flux or dephosphorization flux of hot metal pretreatment. One of the most practical uses of iron oxide dust is recycling as a form of pellets in the BOF considering easy application and the amount that can be recycled. In the process of making iron dust pellets cement is used as a binder that contains a lot of calcium sulfate. This calcium sulfate is reduced and dissolved in the molten metal during refining in the BOF. If the oxygen content in slag and molten steel is high enough, the reduced sulfate cannot be dissolved into molten metal and it can be removed as SO_x gas. The behaviour of calcium sulfate has been studied using of 50kg high frequency induction furnace and industrial‐scale plant tests were carried out at a 300ton BOF. The results show that for low carbon steels the evaporation of decomposed sulfate increases with increasing oxygen content in the slag while for high carbon steels the decomposed sulfate is reduced into the molten metal.     

泡塑吸附硫脲解脱导数分光光度法测定地质样品中的金

文章探讨了导数分光光度法测定地质样品中金的方法:样品经过王水溶解后,在pH=3.2的苯二甲酸氢钾的介质中,借助聚乙烯醇(PVA)存在下,金与钼酸盐和罗丹明B(RB)的显色反应进行测定。对3个国标金矿样品的分析显示该方法具有较好的精密度,经本方法测定10多件地质样品中金与氢醌滴定法结果对照,数值均满足DZ/T 0130-2006《地质矿产实验室测试质量管理规范》要求。     

正态分析方法在矿山样本分析中的应用

通过导入正态分布函数,证明标准化后的样本化验数据服从标准正态分布,完成了对化验室数据从定性评价到定量分析的转变,并用具体计算举例说明了该方法对化验数据进行甄别的显著作用。