可溶性聚硅酸铝铁的制备及其在废水处理中的应用

以赤泥为原料,制备了高效无机高分子絮凝剂——聚硅酸铝铁(PSAF),并将该絮凝剂用于处理工业废水．研究絮凝剂的使用效果与投加量、投加方式、pH值、搅拌条件及水样本身性能间的关系．     

Investigation of the separation of scandium and rare earth elements from red mud by use of reversed-phase HPLC

A chromatographic method has been developed for separation and determination of scandium (Sc) and rare earth elements (REEs) in samples from a red mud (RM)-utilization process. Reversed-phase high-performance liquid chromatography (RP-HPLC) with post-column derivatization using 4-(2-pyridylazo)-resorcinol (PAR) and UV–visible detection at 520 nm was tested using different gradient elution profiles and pH values to optimize separation and recovery, primarily for Sc but also for yttrium and the individual lanthanides, from iron present in the samples. The separation was performed in less than 20 min by use of a mobile phase gradient. The concentration of -hydroxyisobutyric acid (-HIBA), as eluent, was altered from 0.06 to 0.4 mol L^–1 (pH 3.7) and 0.01 mol L^–1 sodium salt n-octane sulfonic acid (OS) was used as modifier. Very low detection limits in the nanogram range and a good resolution for Sc and REEs except for Y/Dy were achieved. Before application of the method to the red mud samples and to the corresponding bauxites, Sc and REEs were leached from red mud with 0.6 mol L^–1 HNO₃ and mostly separated, as a group, from the main elements by ion exchange/selective elution (6 mol L^–1 HNO₃) in accordance with a pilot-plant process developed in this laboratory. After evaporation of the eluent to dryness the extracted elements were re-dissolved in the mobile phase. By use of this chromatographic method Sc, which is the most expensive of the elements investigated and occurs in economically interesting concentrations in red mud, could be separated not only from co-existing Fe but also from Y/Dy, Yb, Er, Ho, Gd, Eu, Sm, Nd, Pr, Ce and La. All the elements investigated were individually recovered. Their recoveries were found to be nearly quantitative.     

Oil Base Mud. Part I: Synthesis of Some Local Surfactants Used as Primary Emulsifiers for Oil Base Mud and Evaluation of Their Rheology Properties

Six oil soluble nonionic surfactants with different HLBs have been prepared. Their HLBs situate between 3.9 and 6.7. Transesterification was carried out for glycerol and triethanol amine with oleic acid at different moles to obtain six emusilifiers. They named glycerol momooleate (I), glycerol diooleate (II), glycerol trioleate (III), triethanol amine mono-, di- and tri-oleate (IV), (V,) and (VI). The chemical structure was confirmed using; the elemental analysis, FTIR and ¹HNMR. They were evaluated as a primary emulsifiers (PE) for thdrilling fluids (oil base mud) comparing with a currently used primary emulsifier (Fc). The water in oil base mud (w/o emulsions) was prepared. The concentration of emulsifiers and their HLB exhibited interesting rheology properties including shear-thinning behavior, yield value, viscoelastic effects, thixtropy, gel strength, and filtration loss. The rheology properties of such emulsions strongly depended on the average size distribution of the dispersed droplets that could be varied both with the bulk concentration and HLB value of the emulsifiers. The interfacial and surface properties of these emulsifiers suggest that the droplet size of the dispersed phase and bulk concentration are strongly related to the HLB value of emulsifiers. The w/o emulsion (mud formulation) stability is sensitive to the droplet size of the dispersed phase and HLB value of the used emulsifier. The results were discussed on the light the chemical structure of the primary emulsifiers and the emulsion ingredients.     

Fabrication of ionic liquid-cellulose-silica hydrogels with appropriate thermal stability and good salt tolerance as potential drilling fluid

This paper investigates the rheological properties of methylcellulose-silica-ionic liquid nanocomposite (2-MCPS-MC) on the rheological properties (apparent viscosity (AV), plastic viscosity (PV), yield point (YP), 10-s gel strength, 10-min gel strength, and thixotropy according to API requirements) of water-based mud, and comparing these properties with the properties of the silica-free methylcellulose (MC) as drilling fluid additive. The physicochemical properties of the MC and 2-MCPS-MC compounds were studied using ¹H NMR, FTIR, Raman-spectroscopy, XRD, FE-SEM, AFM, and TGA. By FE-SEM and AFM, it is proven that the silica had an excellent dispersion in a spherical shape on the MC polymer. Three samples were prepared: the first is the commercial water-based mud, while the second and the third samples are MC and 2-MCPS-MC, respectively. The samples of MC were prepared in four concentrations (2%, 1.5%, 1.0% and 0.5% by weight). Throughout the test, density remained at 7.6 (lbs/gal) for mud fluid and 8.5 (lbs/gal) for MC and 2-MCPS-MC at pH 9.0. The results confirmed that the optimum concentration of MC and 2-MCPS-MC, which meet the required API code, was between 1 and 1.5%. The addition of 2-MCPS-MC to water-based mud enhances filtration properties. Response surface technique (RSM) with central composite design (CCD) was also used to optimize the drilling fluid properties to achieve the optimal response to AV, PV, YP, Gl, and Thixotropic using a Design expert software. The results obtained by RSM showed consistency between the experimental and theoretical data.     

The wave attenuation on the mud bed

In the paper the wave attenuation in a two layer fluid system is studied. The fluid in the top layer is ideal and that in the lower layer is the Voigt model of the viscoelastic medium. A dispersion relation is derived and the rate of the wave decay is computed. The approximate explicit expressions of the decay rate for different water depth are given, where the viscoelasticity is either very large or very small. Compared with the numerical results, our results are very accurate, which can be used by an engineer. The project supported by the National Natural Science Foundation of China and by the Lianyungang Port Office, China     

Method of Probabilistic Convolutions for Interpreting Data of Electromagnetic Logging

A new method is proposed for processing the data of electromagnetic logging in wells. The method is based on the hydrodynamic analysis of drilling mud filtrate penetration into the oil stratum, determination of the field of electrical resistances of the near-well zone with its subsequent averaging by convolutions with a kernel in the form of a logarithmically normal distribution of probe sensitivity.     

Numerical Solution and Sensitivity Analysis of Pore Liquid Pressure and Cake Porosity to Model Parameters

Filter cake formation is important in groundwater and oil wells where drilling contains suspended mud particles. The accumulation of these mud particles on the borehole wall creates a pressure drop in the well. Furthermore, the migration of colloidal particles into adjacent porous rock could damage the formation and cause productivity decline. In this study, numerical solutions for pore liquid pressure variation across the cake with variable total stress and associated porosity variation are obtained. Mass equations for captured and suspended particles are averaged along the mud cake thickness, taking into account conditions on the cake surface and at the filter septum. The variability of total stress in soil consolidations problem is considered to determine the pore liquid pressure along the mud cake thickness. Then, the relation between porosity and pressure is studied to determine the mud cake porosity. Experimental data obtained by various researchers is used to compare and test the validity of numerical solutions to develop guidelines for model applications. Results show that the pore liquid pressure increases with the decrease of membrane impedance value (i.e. less pervious membrane). Also, the pressure profile has a cubic function of dimensionless cake thickness. The conclusions from the sensitivity analysis conducted in this study agree with earlier conclusions.     

坝前淤泥土与新填坝体接触面抗剪强度试验研究及工程应用

坝前淤泥面与新填筑坝体接触面是"坝前淤泥面加坝"技术的薄弱环节。为了探究不同工况下淤泥坝基、新填筑坝体,以及淤泥土-新填土接触面的剪切强度特性,以宁夏南部山区西吉县南川水库坝前淤泥面加坝工程为研究对象,通过常规应变式直剪仪、改进常规应变式直剪仪分别进行剪切试验,分析了淤泥土含水率和压实度变化时,淤泥土、新填土、淤泥土-新填土接触界面的抗剪强度、黏聚力、内摩擦角的变化规律。试验结果表明:新填土抗剪强度最大,不同工况下淤泥土-新填土接触界面的抗剪强度介于淤泥土和新填土的抗剪强度之间;淤泥土含水率在12%~16%之间存在最优含水率,超过该含水率后,淤泥土及淤泥土-新填土接触界面之间的抗剪强度均显著降低;当淤泥土含水率从8%增加至12%、16%时,黏聚力减小8%左右后迅速减小至22%,具有明显的阶段性,而淤泥土-新填土接触界面的黏聚力呈现先增加后减小的趋势;当含水率相同时,随着压实度的增加,淤泥土、淤泥土-新填土接触面的黏聚力、内摩擦角总体呈增大趋势。最后根据试验结果对"坝前淤泥面加坝"工法的工程应用提出了相关建议。     

海底边坡稳定分析方法综述

本文指出海底边坡与陆上边坡的不同点,对一个完整的海底边坡稳定问题从几何形状和载荷情况两个方面进行了描述。由于波浪影响是海底边坡问题的最大特点,因此回顾了计算海底压力的各种方法以及在海底压力作用下海底土层产生的瞬态和残余孔隙压力。然后对极限平衡、静态变形分析和动力分析三大类边坡稳定分析方法进行了评述,并指出各自的适用范围。海底边坡破坏后的行为尤其复杂,指出用流变模型预测泥流性质的可能性。最后提出了海底边坡稳定性课题的当前致力方向。      

ENERGY PRINCIPLE OF THREE DIMENSIONAL J INTEGRAL

Various exprressions of three-dimensional J integral are proposed. We derive here three-dimensional J integral by means of general potential energy principle and Green's theomem. Its physical meaning and application are shown in the paper, the results are true both for infinitesimal and finite deformation.