论硫铁矿烧渣的再生与利用

介绍硫铁矿烧渣的一般特征,再生利用现状和存在问题,提出合理利用和保护资源,维护生态环境。     

硫铁矿烧渣制备铁系化工产品研究方法综述

硫铁矿烧渣是一种二次资源,对其综合利用正引起广泛重视。目前烧渣的利用主要是围绕着铁系化工产品:铁盐(制取硫酸亚铁、二氯化铁),铁系颜料(制取氧化铁红、氧化铁黄、氧化铁黑),铁氧体材料——高纯磁性氧化铁,净水剂(生产聚合硫酸铁及复合净水剂)。今后,探索硫铁矿烧渣更好的综合利用,将会成为研究热点,这依赖于硫铁矿烧渣浸液中高效除杂剂的筛选和合理的除杂工艺。     

直接酸溶法浸取硫铁矿烧渣中铁的实验研究

对常压下用盐酸直接酸溶提取硫铁矿烧渣中的铁进行了实验研究，探讨了影响硫铁矿烧渣酸溶的因素。结果表明，影响铁溶出率的主要因素为液固比、反应时间和温度；当液固比为4．0mL／g、反应温度100℃时，高速搅拌反应2h后，铁的溶出率可达72％，浸取液经进一步处理可生产氯化铁系列产品，有较好的应用前景。     

硫铁矿烧渣特性及综合利用

硫铁矿制取硫酸过程中产生大量烧渣，该渣现多大量堆存。烧渣中含铁量较高，有些含有一定量的铜等有色金属及其它有价金属，具有很大的回收利用价值。目前国内外采用重磁选、焙烧等法回收。通过对烧渣深加工的初步研究，已显示出其综合利用的前景。     

矿渣磷酸镁水泥的力学性能和水化机理

以高炉矿渣作为磷酸镁水泥(MPC)的活性混合材料,研究了MPC的凝固时间、力学性能、物相组成和显微结构,并探讨了矿渣MPC的作用机理。实验固定磷镁比为25%,硼镁比为7.5%,矿渣掺量分别为磷镁总质量的0%、10%、20%、30%和40%。结果表明,矿渣参与了水化反应并提高了MPC的胶凝性能,随着矿渣掺量增大,矿渣MPC的抗压强度提高,但矿渣水化产生的膨胀应力会破坏MPC的内部结构,因此其抗折强度随矿渣掺量增大而降低。矿渣MPC的主要水化产物为六水合磷酸镁铵(MgNH4PO4.6H2O),矿渣的掺入使凝胶相增加,并有部分Ca2+进入MgNH4PO4.6H2O晶格,使水化产物的形貌、大小发生变化。样品中剩余较多死烧镁和矿渣颗粒,可起骨料作用。     

矿渣微细粉掺量对水泥水化产物的影响

利用X射线衍射、TG-DSC综合热分析以及环境扫描电子显微分析技术等,研究了矿渣微细粉对水泥水化产物钙矾石、Ca(OH)₂、CSH凝胶等的影响规律。研究结果表明,在水化早期,矿渣微细粉即参与水泥水化进程,显著影响水泥水化产物钙矾石、Ca(OH)₂和CSH凝胶等的生成速度和生成量及微观形貌,并且随着其掺量增大及水化时间延长,矿渣微细粉参与水泥水化反应程度逐渐提高。     

再论偏岭石与变高岭石的区别--评《天然烧变高岭石中水铝英石的发现》一文

《矿物学报》１９９５年第４期发表了何宏平的“天然烧变高岭石中水铝英石发现”一文。该文用核磁共振谱中－７９.０×１０－６附近的谱峰,认为该信号来自水铝英石,而不是来自Ａｌ－Ｓｉ尖晶石。这种说法较合理,因刘长龄早就阐明偏岭石在成岩阶段由水铝英石变来。但是我们不同意“天然煤烧变高岭石经后期水化作用变成水铝英石”的观点,而主张“水铝英石是沼泽相原生沉积的;在成岩作用中转变为偏岭石不是煤烧的,有一些理化性质与变高岭石的不同”     

再论偏岭石与变高岭石的区别——评《天然烧变高岭石中水铝英石的发现》一文

《矿物学报》１９９５年第４期发表了何宏平的“天然烧变高岭石中水铝英石发现”一文。该文用核磁共振谱中－７９．０×１０－６附近的谱峰，认为该信号来自水铝英石，而不是来自Ａｌ－Ｓｉ尖晶石。这种说法较合理，因刘长龄早就阐明偏岭石在成岩阶段由水铝英石变来。但是我们不同意“天然煤烧变高岭石经后期水化作用变成水铝英石”的观点，而主张“水铝英石是沼泽相原生沉积的；在成岩作用中转变为偏岭石不是煤烧的，有一些理化性质与变高岭石的不同”     

高岭石对稠油氧化影响的DTA-TG分析

运用NETZSCH STA 409PC同步热分析仪针对新疆克拉玛依油田红浅扩大试验区中的稠油样品在氧化过程中高岭石的影响,分析测试。研究结果表明,高岭石的加入影响了稠油的低温及高温氧化反应,使稠油的低温氧化DTA峰值温度从437.6℃增加为455.4℃;高温氧化DTA峰面积显著减小,峰值从607.8℃减小为597.8℃;高岭石含量的增加,有利于降低稠油的低温,高温氧化的DTA峰值温度。随着升温速率的增加,混合样品中稠油的低温,高温氧化及高岭石脱羟基反应呈现为动力学过程。研究结果有助于深入认识原油的氧化过程,对提高采收率和推动稠油油藏的有效开发具有重要的意义。     

利用油页岩灰渣制备通用硅酸盐水泥

采用正交试验确定水泥熟料最佳组成配比：石灰饱和系数为0.92、硅率为2.5、铝率为1.5;水泥熟料最佳煅烧温度为1 350 ℃。按上述条件,利用工业原料配制水泥熟料,根据其XRD结果可知,矿物组成与吉林亚泰水泥厂的熟料相似。将油页岩灰渣作为混合材,直接掺加到水泥厂熟料中。实验结果表明：随着油页岩灰渣掺量的增加,3 d强度下降明显;但后期补强作用较高,28 d强度较为稳定;在水泥强度满足PC32.5标准的前提下灰渣的最大掺加量以35%～40 %为宜。     

Application of Deep Mixing Method with Cement Hardening Agent to Reinforcement of Ground

Considering the specific conditions of deep soft ground in Wuhan, the deep cement mixing method was developed from 1987， in order to reinforce the soft ground. Since then, variety of testing studies both in lab, and in field have been made. From September to October in 1987, this method was first used to reinforce soft ground satisfied completely design requirement with allowable bearing capacity of 16 t/m2 .     

加固软土地基的水泥系深层搅拌法开发

我们从1987年起、针对武汉地区深厚软粘土层的特点,开发了用以加固软土地基的水泥系深层搅拌法,开展了各种类型的室内和现场的试验研究。 1987年9、10月份,在武汉首次运用这种方法,对一幢8层住宅楼的软土地基进行加固,加固土的强度完全满足设计要求,复合地基的容许承载力达到10t/m~2。     

水化对泥页岩力学性质影响的实验研究

在井眼失稳机理分析的基础上,经室内实验得出泥页岩水化后岩石力学参数的变化规律。页岩水化前后坍塌压力对比结果表明,水化使泥页岩的坍塌压力持续升高,证实了泥页岩地层在钻遇初期稳定、裸眼一段时间后出现失稳。      

水泥浆的流变性及其对浆液运动的影响

概括地分析了现有水泥浆流变性的研究成果,采用模拟计算方法,就浆液流变性对灌浆的影响程度作了定量评价。认为新拌水泥浆,可近似看作是一种与时间有关的粘塑性流体,浆液的动切力、塑性粘度和水化速度对其扩散距离都有着不同程度的影响。     

Effect of Natural Zeolite and Cement Additive on the Strength of Sand

It is widely known and well emphasized that the cemented sand is one of economic and environmental topics in soil stabilization. In some instances, a blend of sand, cement and other materials such as fiber, glass, nano particle and zeolite can commercially be available and effectively used in soil stabilization especially in road construction. In regard to zeolite, its influence and effectiveness on the properties of cemented sands systems has not been completely explored. Hence, in this study, based on an experimental program, it has been tried to investigate the potential of a zeolite stabilizer known as additive material to improve the properties of cemented sands. A total number of 216 unconfined compression tests were carried out on cured samples in 7, 28 and 90 days. Results show unconfined compression strength and failure properties improvements of cement sand specimens when cement replaced by zeolite at optimum proportions of 30 % after 28 days due to pozzolanic reaction. The rate of strength improvement is approximately 20–78 and 20–60 % for 28 and 90 days curing times respectively. The efficiency of using zeolite has been enhanced by increasing the cement content and porosity of the compacted mixture. The replacement of cement by natural zeolite led to an increase of the pH after 14 days. Chemical oxygen demand (COD) tests demonstrate that the materials with the zeolite mixture reveal stronger adsorptive capacity of COD in compare to cemented mixture. Scanning electron microscope images show that adding zeolite in cemented sand changes the microstructure (filling large porosity and pozzolanic reaction) that results in increasing strength.     

脱硫石膏晶须对水泥石性能的影响

分析了石膏晶须在不同碱溶液条件下的稳定性,通过测试水泥石的力学性能、水化热、孔隙率、断面形貌和水化产物等,分析晶须增强增韧水泥石的机制。结果表明:晶须能稳定存在水溶液中,但在碱性溶液中,部分参与水化;脱硫石膏晶须掺量在2%时,抗压强度和抗折强度最佳;脱硫石膏晶须可提高水泥浆体的水化加速期的反应速率;当掺量在2%,水化放出的热量最大,可促进水泥水化;未水化的晶须通过桥联搭接作用提高水泥石的韧性,部分水化晶须参与水泥水化反应生成适量的钙矾石,从而提高水泥石的力学性能。     

The Effect of Gum Arabic on the Dispersion of Cement Pastes

Gum arabic, an inexpensive dispersant widely used in the food industry, has great potential for application in building materials. In order to find out the dispersion effect of gum arabic and the factors influencing the holding capacity of gum arabic in cement during hydration, rheological properties of cement paste with added gum arabic were assessed in this paper. The results show that 0.10wt%-0.60wt% of gum arabic positively affects dispersion, lower dosages have negligible effect. High speed mixing is required to maintain the dispersion stability of gum arabic in cement paste. The optimum dosage of gum arabic to achieve best disperse-holding capacity of cement paste was 0.3wt%, and the minimum water-cement ratio needed to obtain a dispersion effect was 0.28.     

Effect of Cement and Quarry Dust on Shear Strength and Hydraulic Characteristics of Lithomargic Clay

The lithomargic clay constitutes an important group of residual soils existing under lateritic soils. This soil is found on the western and eastern coasts of India over large areas. This soil is a problematic one and is very sensitive to water and loses a greater part of its strength when becomes saturated. These high silt deposits have invited many problems such as slope failures, foundation failures, embankment failures, uneven settlements etc. In this investigation an attempt is made to study the effect of cement and quarry dust on shear strength and hydraulic characteristics of the lithomargic clay after the stabilization. Microfabric and mineralogical studies were carried out to find out the reason for the strength development of the stabilized soil using SEM and XRD analysis. The results indicated that there is an improvement in the properties of the lithomargic clay with the addition of cement and quarry dust. The XRD results indicated the formation of CSH and CAH, which are responsible for strength development in the stabilized soil.     

Effect of Cement Type on the Mechanical Behavior of a Gravely Sand

The behavior of a cemented gravely sand was studied using triaxial compression tests. Gypsum, Portland cement and lime were used as the cementing agents in sample preparation. The samples with different cement types were compared in equal cement contents. Three cement contents of 1.5%, 3.0% and 4.5% were selected for sample preparation. Drained and undrained triaxial compression tests were conducted in a range of confining pressures from 25 kPa to 500 kPa. Failure modes, shear strength, stress–strain behavior, volume and pore pressure changes were considered. The gypsum cement induced the highest brittleness in soil among three cement types while the Portland cement was found to be the most ductile cementing agent. In lower cement contents and lower confining pressures the soil cemented with Portland cement showed the highest shear strength. However, in the same range of cement content, the soil cemented with gypsum showed highest shear strength for highest tested confining stress. For higher cement contents the shear strength of soil cemented with Portland cement is higher than that for the two other cement types for the range of confining pressures tested in the present study. The samples cemented with lime had the least peak and ultimate shear strength and the highest pore pressure generation in undrained tests. Contrary to the soil cemented with lime, the brittleness of soil cemented with gypsum and Portland cement reduces in undrained condition. Finally it was found that the effect of cement type on the shear strength of cemented soils is more profound in drained condition compared to undrained state.