Activation of Ground Blast-Furnace Slag by Alkali-Metal and Alkaline-Earth Hydroxides

The effects of pH, time, valence, and radius of the activator cation on the reaction products and microstructure of ground granulated iron blast-furnace slag were studied by thermogravimetry and derivative thermogravimetry, X-ray diffractometry, scanning electron microscopy, and energy dispersive X-ray microanalysis. Blast-furnace slag was activated by alkali-metal hydroxides of Li, Na, and K (12.34 pH 14.71) and alkaline-earth hydroxides of Ca, Sr, and Ba(12.47 pH 13.53) using a water/slag ratio of 0.4 and curing for 1 day to 26 months. Reactivity of the slag was more strongly dependent on pH than on time. The reaction products were mainly varieties of C─S─H, (C,M)₄AH₁₃, and minor amounts of Ca(OH)₂ and C₂ASH₈ (strätlingite). The nature of C─S─H was dependent on pH. A 1.2-nm peak appeared in X-ray diffractograms only when the activation pH was ⌣14.7. Water was present in the C─S─H in a way similar to water in tobermorite and synthetic C─S─H. Leached Ca from unreacted blast-furnace slag was present around the glass particles as an amorphous layer which crystallized into Ca(OH)₂ with time; Mg behaved similarly. The effect of the charge or ionic radius of the activator cation was insignificant.     

电石渣激发钢渣-矿渣固化淤泥质土的试验研究

钢渣和矿渣是常见的两种工业废渣,大量堆放且资源化利用困难。以钢渣粉和矿渣粉为基础材料,电石渣粉作为激发剂,可对淤泥质土进行固化处理。通过开展无侧限抗压强度试验,分析固化淤泥质土的强度特性和应力-应变关系,利用X射线衍射(XRD)和扫描电镜(SEM)等微观测试,探索电石渣激发钢渣-矿渣固化淤泥质土的作用机理。结果表明,电石渣粉质量掺量为6%时,电石渣-钢渣-矿渣固化淤泥质土无侧限抗压强度最大,28 d固化淤泥质土强度与同龄期水泥土相当,且具有较好的延性。电石渣可以提供碱性环境和大量钙离子,有效激发钢渣和矿渣的水化活性,促进C-S-H凝胶的大量生成,同时促进离子交换和团粒化作用,使固化淤泥质土强度显著提高。     

粒化高炉矿渣微粉固化淤泥质土的动力特性及微观机理

采用不同掺量的粒化高炉矿渣微粉(GGBS)对淤泥质土进行固化处理,利用动三轴试验,确定GGBS的最优掺量,并分析最优掺量固化土在不同围压下的动强度、动弹性模量和动阻尼比的变化规律,最后利用SEM和EDS分析固化土的微观结构和元素变化,揭示其固化机理.结果表明,当GGBS掺量为20％(质量分数,下同)时,固化土动强度呈台...     

Hydration Products and Reactivity of Blast-Furnace Slag Activated by Various Alkalis

Pastes of blast-furnace slag were cured for up to 90 d using sodium silicate (waterglass), NaOH, and three different mixtures of Na₂CO₃–Na₂SO₄–Ca(OH)₂ to activate reactions. The highest slag reactivity was observed for NaOH activation and the least for waterglass, although nonevaporable water indicated similar amounts of hydration products formed. The main hydration products found using X-ray diffractometry in all systems were calcium silicate hydrate (C-S-H) and a hydrotalcite-type phase. Microanalysis was performed on pastes activated using 50% Na₂CO₃·25% Na₂SO₄·25% Ca(OH)₂, NaOH, and waterglass; the chemical composition of the C-S-H in the waterglass case was different relative to the other two alkalis. For all alkaline agents used, the C-S-H seemed finely intermixed with a hydrotalcite-type phase of Mg/Al = 1.82, on average.     

钢渣矿渣水泥碱性激发剂的研究

以钾长石和纯碱为原料,在高温下熔制了一种主要成分为钾钠铝硅的碱性玻璃体激发剂.测定了该激发剂在常温(20℃)下的溶解度和溶解速率以及对钢渣、矿渣复合系统的激发效应,实验证明:玻璃体结构的碱性激发剂能有效控制钢渣、矿渣复合系统的凝结时间,激发效应显著.     

KR脱硫渣碱激发矿渣的配比优化及水化特性

KR脱硫渣是铁水脱硫工序产生的废渣,多种固废协同制备胶凝材料是脱硫渣资源化的有效途径。本文利用KR脱硫渣、矿渣和脱硫石膏制备固废基胶凝材料,研究KR脱硫渣和矿渣掺量对胶凝材料力学性能的影响,优化原材料配比。通过XRD、TG-DSC、IR、SEM-EDS和水化热测试方法研究了固废基胶凝材料的水化产物及水化特性。结果表明,固废基胶凝材料优化配比为KR脱硫渣25%(质量分数,下同),矿渣60%,脱硫石膏15%,胶凝材料3 d、28 d、90 d抗压强度分别达到30.01 MPa、49.47 MPa和55.73 MPa。固废基胶凝材料的早期水化放热速率低,3 d累积放热量仅为普通硅酸盐水泥(OPC)的37.9%,其水化产物主要是针棒状钙矾石(AFt)和无定形水化硅酸钙(C-S-H)凝胶。KR脱硫渣中大量的Ca(OH)₂在水化早期可以碱激发矿渣,使玻璃相硅酸盐解体,同时与脱硫石膏反应促进AFt的生成。KR脱硫渣、矿渣和脱硫石膏协同反应使水化后期的水化产物持续增加,相互胶结形成致密结构,有利于强度的持续增长。     

利用钢渣、矿渣制备低碳型胶凝材料

以钢渣、矿渣和脱硫石膏为主要原料,添加少量激发剂制备低碳型胶凝材料,试验确定了制备该产品的最佳物料配比:矿渣41.75%,钢渣41.75%,800℃锻烧的脱硫石膏10%,硅酸盐水泥熟料5%,激发剂Ⅱ1.5%.产品达到GB175-2007<通用硅酸盐水泥>42.5复合硅酸盐水泥标准要求.     

Granularity and Surface Structure of Ground Granulated Blast-Furnace Slags

Ground granulated blast-furnace slags (GGBS) show improved hydration reactivity when granularity fineness increases, but the reason for the improvement in reactivity is still unknown. GGBS specimens with Blaine surface areas of 4680, 6470, and 8050 are analyzed, but the conventional reactivity criteria, such as degree of vitrification, basicity, and mineralogical composition, of the GGBS show no significant differences. X-ray photoelectron spectroscopic analysis, however, successfully distinguishes and identifies SiO₂ gels as well as glassy phases of CaO-SiO₂ and Al₂O₃-SiO₂ in the slag surfaces, where, with an increase in the Blaine surface area of the slag, CaO-SiO₂-type glass becomes dominant and contributes to the evolution of hydration, determined in terms of silicate anion morphology by the trimethylsilylation (TMS) method.     

Characterization by Multinuclear High-Resolution NMR of Hydration Products in Activated Blast-Furnace Slag Pastes

The effect of activators on the hydration of granulated blast-furnace slag (gbfs) was studied through compressive strength measurements, ²⁹Si, ²⁷Al, and ²³Na high-resolution nuclear magnetic resonance, and X-ray diffraction. Four different activations containing sodium hydroxide, sodium silicate, and/or calcium hydroxide (CH) were considered, at fixed amounts of alkali: 5% Na₂O, 5% Na₂O-2.5% CH, 5% Na₂O-7.5% SiO₂, and 5% Na₂O-2.5% CH-7.5% SiO₂. Silicate-activated gbfs cements have greater compressive strength than Portland cements over the whole period of study (1 yr). Also, silicate-free activated gbfs cements have poorer mechanical strength than silicate-activated cements. In fact, substantial structural differences were observed between hydration products in both kinds of activations. In silicate-activated pastes there exists an intimate mixture of C-S-H layers and AFm-like arrangements containing Al in octahedral sites bonded to the silicate layers, originated either from phase intergrowths or from a high density of Ca-Al incorporation in the interlayer spaces of C-S-H. In pastes obtained from silicate-free activation of gbfs there is a better chemical and structural definition among C-S-H and calcium aluminate hydrate domains (AFm and hydrogarnet).     

利用废玻璃和高炉渣制作泡沫玻璃的研究

本文研究了利用废玻璃和高炉渣制作泡沫玻璃的可行性，实验表明，用部分高炉渣代替废玻璃不仅可以制备出性能优良的泡沫玻璃，而且可以降低烧成温度，高炉渣的加入量为10%时，效果最佳，这将对泡沫玻璃的生产具有一定的实际意义。     

掺粒化高炉矿渣粉预拌混凝土及其在工程中的应用

介绍掺加粒化高炉矿渣粉预拌混凝土的研究和应用.     

钢渣吸附活化动力学机理分析

为了深化研究钢渣活化动力学,研制高效活化剂,以钢渣粉作为吸附剂,利用振荡吸附方法,试验研究了钢渣粉对单体碱性活化剂的吸附作用.同时,采用气相色谱分析,测试了钢渣内[SiO4]4-单体含量,据此分析了钢渣的水化活性及机理.结果表明:钢渣的化学组成和结构与活化剂之间具有某种程度的匹配性,钢渣的活性一部分来自于定量解聚,即决定于[SiO4]4-单体的数量与活化剂种类及掺量多少,以及钢渣自身是否存在较多C3S、C2S矿物成分而具备一定水化能力;另一部分产生于钢渣的定性缩聚,即在适宜的活化剂及掺量作用下,Si-O-Al间的“焊接”键能得到了增强,使钢渣胶凝活性得到提高.     

Application of Secondary Carbon Fiber for Reinforcing Composite Material Based on Alkali-Activated Blast-Furnace Slag

Glass and Ceramics - The potential for using secondary carbon fiber, recovered from aviation carbon fiber wastes, for reinforcing composite materials based on blast-furnace slag activated by a...     

钢渣-矿渣复合微粉活性试验研究

<正>我国钢铁产业每年排放3000多万t钢渣,钢渣的资源化利用越来越受到重视。钢渣中含有一定数量的C2S、C3S、C3A等,理论上可看作一种低活性的水泥熟料,钢渣粉与矿渣粉复掺可以用作混凝土掺合料,两者有相互活化的效果,不仅能够降低混凝土成本,而     

机械活化和不锈钢渣掺量对矿渣胶凝材料性能的影响

为了促进不锈钢厂废渣的资源化利用,以红土镍矿酸性高炉渣和不锈钢渣为主要原料制备胶凝材料,研究机械活化和不锈钢渣质量掺量对矿渣胶凝材料性能的影响,并利用XRD、SEM对胶凝材料的水化产物及微观结构进行分析。结果表明,机械活化主要通过改变原料的比表面积和颗粒级配来影响胶凝材料性能,且矿渣中细颗粒占比是影响其胶凝活性的关键因素,适宜的球磨时间为45 min,此时矿渣比表面积达到524.66 m²/kg。不锈钢渣与酸性矿渣之间存在协同作用,当不锈钢渣质量掺量为20%时,胶砂试块3 d、7 d、28 d抗压强度分别为17.8 MPa、24.3 MPa 和34.8 MPa,抗折强度分别为4.5 MPa、6.2 MPa和6.8 MPa,达到P·S 32.5R矿渣硅酸盐水泥强度标准。不锈钢渣的掺入在水化早期和后期都促进钙矾石及C-S-H凝胶的生成,对胶砂试块各龄期强度都有促进作用,而未水化的钢渣细颗粒也起着微集料填充作用,有利于胶凝材料早期强度的提高。     

钢渣活性激发及其机理的研究进展

钢渣是炼钢时的副产品,具有和水泥熟料相类似的矿物和化学组成,因此具有潜在的活性.本文介绍了目前4种主要的钢渣活性激发方法,即预激发、物理激发、化学激发以及热力学激发.并详细地分析了各种方法的激发机理,及重点阐述了碱激发和酸激发的激发效果.最后做出预测:未来应着重采用物理和化学相结合的方法对钢渣活性进行激发.     

硫化胶粉的活化研究

研究过渡元素金属盐／有机胺对胎面硫化胶粉的活化，以及胶粉粒度、活化温度和时间与活化胶粉硫化胶物理性能的关系。实验结果表明：氯化亚铜／二亚乙基三胺对硫化胶粉的活化效果较好；增大活化体系中氯化亚铜和二亚乙基三胺的浓度，减小硫化胶粉的粒度，采用较低的活化温度，均可提高硫化胶粉的活化效果。