水泥立磨终粉磨产品性能研究及其技术展望

从水泥颗粒粒形、颗粒分布、水泥颗粒预水化等方面对立磨终粉磨工艺系统生产的水泥产品特性进行系统研究，结论是：在3～10μm和10～32μm这两个对水泥强度起主要作用的水泥颗粒的分布区间内，立磨终粉磨的水泥粒形、球形度、表面粗糙度与球磨粉磨相比，没有根本性的区别；立磨终粉磨的水泥颗粒特征粒径与球磨几乎没有差别，但立磨终粉磨的水泥的颗粒分布更窄，会导致标准稠度用水量增加；立磨内喷水稳定料层的操作会造成磨内水泥颗粒预水化，且随着喷水量增大，预水化程度越高，导致强度下降，凝结时间降低。立磨终粉磨工艺用于水泥精准分别粉磨系统，需开发新的受控料床稳定技术、梯级选粉装置和精细混合工艺。     

分别粉磨与共同粉磨对石灰石硅酸盐水泥颗粒分布及水化性能的影响

试验采用分别粉磨工艺和共同粉磨工艺配制石灰石硅酸盐水泥,分析了石灰石和熟料的粉磨特性差异,并研究了在单位能耗相同情况下,两种粉磨制度下石灰石硅酸盐水泥各组份颗粒分布及水化情况。结果表明,分别粉磨制度能合理控制石灰石硅酸盐水泥颗粒的分布,使熟料处于更细的颗粒范围内,提高了粉磨效率;细的石灰石粉能促进水泥的早期水化反应,而中后期的水化速率主要取决于熟料颗粒的细度;采用合理的分别磨粉工艺配制的石灰石硅酸盐水泥,在相同龄期下,其水化产物含量较多,水化产物之间的连结更紧密,水泥石整体结构更密实。     

不同粉磨工艺水泥颗粒分布参数的计算与对比分析

通过对实测的水泥成品颗粒体系分布特征及参数的计算,介绍了采用RRB原型方程直接求解颗粒分布方程参数的方法,选取了辊压机联合粉磨等5种国内的主流粉磨工艺所制备的水泥成品进行颗粒分布测试和分析。结果表明：辊压机联合粉磨、外循环立磨联合粉磨和半终粉磨工艺所制备的水泥成品颗粒均匀性系数均较低,辊压机半终粉磨工艺制备的水泥成品颗粒均匀性系数较高,而外循环立磨终粉磨工艺制备的水泥成品颗粒均匀性系数稍低于辊压机半终粉磨工艺。     

磨球级配与水泥颗粒级配关系的研究

正0引言水泥颗粒级配影响因素很多,如物料的配比、物料的易磨性、产成品细度控制、粉磨工艺系统的配置、工艺参数的控制等等。影响粉磨工艺因素也有多种,如粉磨工艺系统配置有辊压机半终粉磨、立磨、双闭路联合粉磨、单闭路联合粉磨、闭路磨、开路磨等等;水泥磨钢球级配是否合理;循环负荷与选粉效率、风速、风压的控制等等。1水泥磨钢球级配与水泥颗粒级配关系研究我公司为Φ3.8m×12m双仓闭路水泥磨,前配140-65辊压机。就水泥磨钢球级配与水泥颗粒级配关系研究方面,笔者主要分以下四个阶段实施。     

粉磨工艺对水泥颗粒分布及其混凝土性能的影响

研究了不同粉磨工艺系统磨制水泥的颗粒分布、粉磨电耗、标准稠度用水量、与减水剂相容性及其配制的混凝土强度、耐磨性、抗碳化性能的差异;针对我国混凝土行业的现状,从混凝土性能的角度出发,探讨了现阶段各种水泥粉磨工艺的特点。研究结果表明,水泥粉磨工艺系统的效率越高,水泥的颗粒分布越集中,水泥的标准稠度用水量增大,与减水剂相容性变差,在缺乏良好的掺合料进行颗粒分布校正的前提下,所配制混凝土的强度、耐磨性及抗碳化性能均有所下降。     

粉磨工艺对水泥性能影响的研究

本文采用筛分和沉降天平分离了不同粒级的水泥物料,分析了不同粉磨工艺条件下水泥物料的颗粒分布及熟料颗粒的分布。研究表明,闭路系统水泥细颗粒较多,且颗粒分布均匀。采用混合粉磨时,尽管测得的水泥颗粒组成不及分磨系统理想,但细粒中熟料含量更高。性能试验显示出,相同比表面积时,混合粉磨水泥较分磨水泥早期强度要高。在分磨系统中提高矿渣的细度对水泥的早期强度发展有利。     

新型粉磨工艺对水泥颗粒分布特性的影响

随着我国社会经济水平与科学技术水平的提升,粉磨工艺得到了飞速的进步,越来越多的粉磨工艺在各行各业中得到了普及应用。为了保证各项工程都能选择到合适的粉磨工艺,对粉磨工艺的特性研究很有必要,本文就是针对新型粉磨工艺对水泥颗粒分布特性的影响进行的探究,希望能为粉磨工艺的合理制定及水泥性能的提升提供依据。     

水泥粉磨工艺对混凝土性能的影响

分别检测了球磨机圈流粉磨工艺和辊压机-球磨机联合粉磨工艺生产的不同强度等级水泥的物理性能及与外加剂的适应性，并将各水泥样配制成混凝土，测试相应混凝土的性能。试验发现，强度高的水泥所配制混凝土的强度不一定高，水泥需水性对混凝土强度的影响甚至超过了水泥强度对它的影响；圈流磨的水泥所配混凝土的强度较高。试验检测了圈流磨及联合粉磨生产的水泥的颗粒组成，分析了联合粉磨的水泥需水性大的原因，找到了控制联合粉磨工艺水泥需水性的工艺指标。     

不同粉磨方式对水泥相关特性影响的研究

采用同一种熟料,通过辊压机终粉磨、辊压机-球磨机联合粉磨和单独球磨三种粉磨方式,研究了水泥颗粒特性,探讨了颗粒特性对水泥物理力学性能的具体影响。试验发现,辊压机终粉磨水泥存在一定的颗粒缺陷,致使水泥的需水性增大和早期水化不良;球磨机粉磨水泥颗粒性能和早强发挥均较优,但其粉磨效率低、能耗高的问题明显;联合粉磨工艺粉磨效率高,水泥颗粒特性和物理力学性能也得到了明显改善。     

立磨对水泥配合料的适应性探讨

通过研究不同组成的立磨终粉磨水泥试样的颗粒特性,并与相同组成的球磨机终粉磨水泥试样的颗粒特性进行比较,探讨了以立磨为终粉磨装置对不同入磨物料的适应性问题。试验研究结果发现,以立磨对水泥进行终粉磨时,其对入磨物料变化的适应性明显不如球磨机终粉磨系统。然而当物料的易磨性越好时,立磨终粉磨水泥的颗粒特性表现就会越好,此时与球磨终粉磨水泥颗粒特性的差距也会明显变小。     

Organosilicone modified styrene-acrylic latex: preparation and application

In this paper, organosilicone modified styrene-acrylic (OSA) latexes for waterproof coating were synthesized through core–shell emulsion polymerization. The influence of emulsifier type and dosage on the size, size distribution and morphology of the latex was systematically investigated. The water absorbance and thermal decomposition behavior and the mechanical properties of the waterproof coating depending on the organosilicone introduced on the latex shell were also studied. Transmission electron microscopy and dynamic light scattering results indicated that the particles had a regular spherical morphology with different diameters and distributions. Thermal gravimetric analysis results revealed that the thermal stability of the latex films was improved with the introduction of organosilicone. The waterproof property of the OSA latex film was obviously increased as compared to that of the styrene-acrylic latex film. The tensile strength and fracture elongation of the elastic waterproof building coating made of the OSA latex and cement powder were significantly greater than that made of the styrene-acrylic latex and cement powder.     

水泥颗粒生长与黏结的微观分析(英文)

水泥微观结果的变化是一个十分复杂的过程,其中包含了水泥颗粒的生长、黏联、絮凝以及其它反应。了解这些水泥颗粒的行为对于更好地掌握水泥基材料早期性能非常重要。采用扫描电子显微镜内安装的Quantomix密封舱系统,原位观察了3种不同的水泥浆体的微观结构。基于这个系统可连续观察水泥浆体微结构发展的优点,研究了水化过程中单个颗粒的生长与颗粒间的连接。通过显微照片的图像分析获得水泥颗粒的灰度变化,用于上述研究。对这些水泥浆体中水泥颗粒的生长与连接情况进行了定量研究。     

高效减水剂在水泥颗粒表面的吸附

采用X射线荧光光谱方法(XRF)研究萘磺酸钠聚合物(PNS)高效减水剂在水泥颗粒表面的吸附。分析认为PNS中硫(S)元素含量是确定的，水化初期其它成分溶入水泥浆液相中的含S离子的变化情况也可以测定，且制定XRF标准曲线所需含S标准样品选取方便，因此S元素是合理的标定元素。从水泥浆体中分离出液相是XRF方法关键的步骤，测试数据表明过滤(抽滤)对XRF结果的误差影响不大。在此基础上，用XRF分析从水泥浆分离出的溶液中S元素的含量，进而计算PNS吸附结果。该结果与其他研究人员采用其它方法所得的研究结果相近。同时发现PNS高效减水剂在水泥颗粒表面吸附形态不是单分子层，而是其它形态。     

页岩气油气井水泥研究及生产制备

为探讨超细油井水泥性能和制备工艺,本文通过采用立式多转子气流分级机对油井水泥进行分级和相应工序处理获得7种不同颗粒粒径的油井水泥。利用激光粒度仪、X射线衍射仪、扫描电镜等分别对不同颗粒粒径油井水泥进行颗粒级配、矿物组成、水泥颗粒形貌及水泥石水化产物进行测试,同时测试稠化时间、稠度、流动度、强度等对其性能进行评价。研究结果表明,油井水泥在分级生产过程中出现分相现象;分级粗油井水泥在合适比例混合下可获得合格产品;不同颗粒粒径的油井水泥微观结构和物理性能差别大,随水泥比表面积增大,水泥颗粒间吸附力增强,浆体稠化时间缩短,初稠和水灰比增大,析水率降低,稳定性增加;在合适温度范围内,随温度升高,浆体强度增加,但颗粒过细,强度反而会下降。     

超细油井水泥性能研究及制备工艺探讨

为探讨超细油井水泥性能和制备工艺,本文通过采用立式多转子气流分级机对油井水泥进行分级和相应工序处理获得7种不同颗粒粒径的油井水泥.利用激光粒度仪、X射线衍射仪、扫描电镜等分别对不同颗粒粒径油井水泥进行颗粒级配、矿物组成、水泥颗粒形貌及水泥石水化产物进行测试,同时测试稠化时间、稠度、流动度、强度等对其性能进行评价.研究结...     

Influence of Cement Particle-Size Distribution on Early Age Autogenous Strains and Stresses in Cement-Based Materials

The influence of cement particle-size distribution on autogenous strains and stresses in cement pastes of identical water-to-cement ratios is examined for cement powders of four different finenesses. Experimental measurements include chemical shrinkage, to quantify degree of hydration; internal relative humidity development; autogenous deformation; and eigenstress development, using a novel embedded spherical stress sensor. Because the latter three measurements are conducted under sealed conditions, whereas chemical-shrinkage measurements are made under "saturated" conditions, the National Institute of Standards and Technology cement hydration and microstructure development model is used to separate the effects of differences in hydration rates (kinetics) from those caused by the different initial spatial arrangement of the cement particles. The initial arrangement of the cement particles controls the initial pore-size distribution of the cement paste, which, in turn, regulates the magnitude of the induced autogenous shrinkage stresses produced by the water/air menisci in the air-filled pores formed throughout the hydration process. The experimental results indicate that a small autogenous expansion (probably the result of ettringite formation), as opposed to a shrinkage, may be produced and early age cracking possibly avoided through the use of coarser cements.     

玻璃/水泥中空纤维膜的制备及碳素截留性能

以玻璃粉、水泥粉、聚偏氟乙烯和N,N-二甲基乙酰胺为原料,通过溶液法纺丝技术制备了玻璃/水泥中空纤维前驱体膜。利用前驱体膜对一定浓度的碳素溶液进行截留测试,同时利用扫描电子显微镜、紫外分光光度计分析前驱体膜的微观形貌和碳素截留性能,探究了水泥粉的掺杂对碳素颗粒截留性能的影响。     

Influence of cement and superplasticizers type and dosage on the fluidity of cement mortars—Part I

Concrete quality is controlled by the flow behavior of cement paste, which is related to the dispersion of cement particles. Superplasticizers (SPs) provide the possibility of a better dispersion of cement particles, thereby producing paste of higher fluidity. With the development of high strength, high performance concrete, SPs are becoming indispensable. SPs are adsorbed on the cement particles. This adsorption is uneven and depends upon the clinker composition of cement and the type of SP used. This work is focused on the study of the influence of lignosulfonic acid (LS)- and melamine sulfonic acid (SMF)-based SPs on the fluidity of mortars made with ordinary Portland (OPC), low alkali (LAC) and white cement (WC) at different water to cement ratio. It is shown that LS are more effective than SMF in providing better fluidity. Further WC has given the highest fluidity among the cements used. It is attributed to the lower C₃A+C₄AF and alkali content, and higher SO₃ content.     

The physical and chemical characteristics of the shell of air-entrained bubbles in cement paste

Recent research has suggested that the shell of an air-entrained void is important for resisting coalescence between air-voids and diffusion of gas from the surrounding fluid. The current paper describes the physical and chemical properties of an air-void shell during the first 2 h of hydration and chemical characteristics at 60 days. Results from this research suggest that the air-void shells found in air-entrained paste have varied physical properties and the crystalline material of these shells is largely made up of fine cement particles during the first 2 h of hydration. Observations of paste at 60 days of hydration suggest that the shell is made up of calcium silicate hydrate (C-S-H) with a morphology different from that in the bulk paste.     

Polyurethane–cement‐based foams: Characterization and potential uses

The production of a new lightweight composite material based on polyurethane and Portland cement was investigated. The composite was obtained by the mixture of polyurethane foam precursors with different amounts of cement and water. To allow cement hydration, samples were aged in water and characterized through scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, and compressive testing. We studied the cement hydration reactions and the effect of the organic phase on hydration by determining the amount of chemically bonded water by calcination. The results showed that the amount of water affected the morphology and porosity of the foams and thereby affected the cement hydration reaction. Furthermore, the mechanical properties of the hybrid composite varied in a wide range, depending on the cement and water contents and on whether the hydrated cement particles behaved as fillers or were allowed to interact to form stronger inorganic networks within the polymeric matrix forming the bubble walls. The polyurethane–cement composite foams showed an increase in the stiffness and the yield strength. In addition, the ductile behavior of the polymeric foams was preserved, even at high filler loadings, due to the chemical compatibility between the hydroxyl groups of the polyol and the cement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008