Effect of content of Al_2O_3 and MgO on crystallization of blast furnace slag during fiber formation

The simulation of blast furnace slag was prepared by pure chemical reagents.Test methods like DSC,XRD and SEM were used to study the effect of Al2O3 and MgO content on crystallization of blast furnace slag during fiber formation.The results show that as Al2O3 and MgO contents in the sample changed,blast furnace slag was crystallized at the average temperature below 1232 K.When the ratio of Mg/Al in the samples is 0.6 calculated by Kissinger equation,crystallization activation energy is at the maximum value and the system is in the most stable condition.The sample crystallization phases are mainly calcium akermanite(2CaO?MgO?2SiO2)and gehlenite(2CaO?Al2O3?SiO2).Secondary crystallization phases are anorthite(CaAl2Si2O8),wollastonite minerals(WOLLA)and pyroxene minerals(cPyrA).Meanwhile,the principal crystallization phases of the samples are different types and have different contents,and the microstructures of the sample sections are different due to the difference between MgO/Al2O3 ratio.

铜车坝水库泥岩石渣坝复合土工膜与振冲碎石桩地基中混凝土防渗墙综合防渗体系的应力变形特性

铜车坝水库泥岩石渣坝综合防渗体系具有振冲碎石桩地基中设置混凝土防渗墙、柔性复合土工膜联结混凝土防渗墙等关键因素,为确保大坝防渗体系的安全性,采用大型三轴试验获得了坝料的邓肯模型参数,建立了准三维有限元模型,在土工膜与上、下垫层料接触部位均设置接触单元,反映土工膜与垫层料之间的接触特性,数值模拟了大坝施工与蓄水过程,阐明了复合土工膜与防渗墙综合防渗体系的应力变形特性。结果表明,泥岩石渣料属于低压缩性土,但其具有较为明显的强度非线性特性;防渗墙各时期的位移变形模式不同,围堰挡水期防渗墙水平位移偏向下游,竣工期逐渐向上游偏移,而蓄水期防渗墙在水压力作用下向下游发展,因此防渗墙上、下表面均存在一定的拉应力区域;土工膜的拉应变主要集中在防渗墙与土工膜的连接处,这是由于该地区刚度差异较大变形非协调所致。研究成果可为设计与施工提供重要的理论与技术支撑。

带钢热镀锌锌渣缺陷形成机理及控制措施

带钢连续热镀锌是目前应用最广泛且具有经济性的防腐技术。然而,热镀锌过程难免会产生锌渣,锌渣的形成不仅会造成锌资源的损失,也会严重影响带钢的表面质量,因此控制锌渣的形成是带钢热镀锌质量控制的关键点。笔者综述了近年来国内外带钢连续热镀锌锌渣缺陷的研究现状,分析了锌渣的形成机理,探讨了锌渣的影响因素,总结了锌渣的控制措施,证明通过一系列设备改进、工艺优化和规范操作等调整,可有效减少锌渣、降低锌耗、节省成本、提高质量。同时,对热镀锌技术锌渣缺陷的进一步有效预防与控制进行了展望。

改良配方水泥搅拌桩现场试桩试验对比研究

水泥搅拌桩在深厚海相淤泥软土中成桩困难,改良配方的水泥搅拌桩研究具有重要的工程意义。本文针对珠海市横琴保税区一道路工程地质情况,研究了5种水泥搅拌桩(4种改良配方和1种未改良对比组)的试桩成桩效果,综合考虑桩身完整性及其强度,对各方案成桩效果进行了定量对比分析。分析结果表明:随着软土层深度的增加,各方案试桩的桩身完整性和强度减小;当粉煤灰掺量为40%或矿渣掺量为31%时,改良的水泥搅拌桩无侧限抗压强度较纯水泥搅拌桩分别提高了104.95%和43.56%;在本场区内,粉煤灰掺量为40%的改良水泥搅拌桩较其它方案更具有适用性;而对于矿渣—水泥改良体系,当矿渣掺入量过高时,水泥搅拌桩的成桩效果随着矿渣掺入量的增加反而降低。

多元固废基胶凝材料的组成优化及强度形成机理

采用钢渣粉、S95矿粉、粉煤灰和脱硫石膏为原材料,通过单纯形重心方法优化设计制备多元固废胶凝材料,以胶砂抗压、抗折强度试验分析了组成成分对固废胶砂力学性能的影响,采用X射线衍射(X-ray diffraction,XRD)、傅里叶红外光谱(Fourier transform infrared spectroscopy,FT-IR)和热重(thermogravimetric,TG)方法探究了多元固废基胶凝材料强度形成机理。结果表明:多元固废基胶凝材料(SFMD)的最佳掺配比为钢渣粉∶S95矿粉∶粉煤灰∶脱硫石膏=31∶38∶27∶4。多元固废基胶砂试件的力学性能随钢渣粉掺量的增加呈先升高后降低的趋势,S95矿粉对胶砂试件早期强度贡献较大,过量的粉煤灰掺入则不利于胶砂强度的形成。SFMD的红外吸收峰在969 cm^(-1)处出现了C-S-H中Si—O的伸缩振动峰,且SFMD中C-S-H的失重最多,该体系的各组分之间的协同效应较好。此外,脱硫石膏可以促使钢渣粉-S95矿粉-粉煤灰体系的协同水化反应更加彻底,生成提供强度的钙矾石。

粉煤气化技术气化炉挂渣操作结论

气化炉在运行过程中易出现水冷壁浇注料脱落、挂渣松散等工况,会造成水冷壁泄漏频繁,严重影响气化炉安全稳定长周期运行。参考某公司1、某公司2和某公司3的气化炉在实际运行状况中的挂渣经验,结合其工艺流程和运行数据,通过对比分析不同煤灰组分和炉膛温度等操作情况,揭示气化炉采用不同煤质和煤灰熔点对挂渣效果之间的相关性。

Resource utilization of slag from desulphurization and slag skimming:A comprehensive recycling process of all components

In order to make the slag from desulphurization and slag skimming(SDSS)to be comprehensively recycled and utilized,a combined process of beneficiation and building materials preparation was proposed to recover iron from SDSS,meanwhile to apply the remaining slag tailings as cement admixture.From this process,three iron-rich products were recovered in stages by clean gravity-magnetic separation,slag tailings were left.Slag powder was prepared by ultrafine grinding of slag tailings.The stability,setting time and cement mortar strength of the slag tailings cements(STC)which were mixed with Portland cement and slag powder were studied respectively.The results showed that a proper overall performance still could be obtained at the slag powder content of 30%.Chemical composition analysis,X-ray diffraction(XRD)analysis,metallographic microscope and scanning electron microscope(SEM)analysis were employed to assess the characteristics of the SDSS and the products obtained from the whole process.The results indicated that the three iron-rich products could be used as a raw material for steelmaking and ironmaking and the relatively large amount of calcium silicate(C_(2)S)and tricalcium silicate(C_(3)S)in the slag tailings make the addition of slag powder into the Portland cement feasible.

风化煤流化床燃烧灰渣形成特性试验

山西风化煤灰分高、热值低,导致其燃烧发电利用受限。前人大量研究了从风化煤中提取腐植酸及其相关应用,但目前鲜见风化煤灰渣形成特性相关试验研究。为探究山西风化煤的灰渣形成特性,以小型流化床反应器为主要试验装置,对风化煤在不同煤颗粒粒径、燃烧气氛下分别进行热态燃烧试验。利用天平、振动筛、马弗炉、激光粒度仪、X-Ray衍射仪分析风化煤灰渣的份额分布、颗粒特性及矿物含量,揭示了不同燃烧工况下风化煤灰渣形成特性的差异。结果表明:随煤颗粒粒径增加,燃煤颗粒炉内磨损程度减弱,飞灰份额由43.20%降至1.51%,石英、莫来石、赤铁矿生成量和高岭石转化量增加;出口烟气中O_(2)体积分数增加有利于高岭石和黄铁矿转化分解生成石英、莫来石和赤铁矿:随出口O_(2)体积分数由0增至5.16%,风化煤底渣中石英质量分数由41.21%增至51.13%,莫来石质量分数由7.24%增至21.42%,赤铁矿质量分数由6.81%增至23.32%。高灰低热值风化煤能在流化床中实现稳定燃烧,出口烟气中O_(2)体积分数3%~5%时,2~4 mm风化煤能保持较高燃烧效率和矿物转化率,有利于燃烧系统稳定高效运行和灰渣二次利用,可作为循环流化床燃料选用依据。

台风暴雨矿渣型泥石流形成机制与动力特征——以兴宁乌石坑沟泥石流为例

受台风“尤特”登陆影响,台风暴雨直接激发兴宁乌石坑沟特大矿渣型泥石流灾害,物源巨大,潜在危害极大。笔者等通过现场调绘及室内试验,对本次泥石流的形成机制及动力特征进行研究,旨在为此类泥石流致灾机理及危害性评价提供借鉴。研究表明,其独特的流域地形特点为泥石流形成的基本因素,以沟道堆积物为主的丰富矿渣型物源是基础条件,高强度的台风暴雨是直接激发因素,与矿山开采、矿渣随意堆放等人为因素共同作用扩大了灾害规模。泥石流形成过程与动力特征为前期强降雨—崩滑碎屑流—矿渣型泥石流—台风暴雨—沟道堵塞雍高—溃决、规模放大。

壳牌煤气化工艺堵渣原因及分析

近年来,由于煤气化技术得到了越来越多的普及,壳牌粉煤加压气流床气化技术作为典型的煤气化技术之一,在运行过程中存在堵渣、合成气冷却器积灰等的难题制约着装置的长周期稳定运行。针对壳牌煤气化工艺的堵渣问题,从煤气化工艺的反应原理、气化装置的流程、渣层的形成、堵渣的现象及判断依据、粉煤的熔融特性、气化炉的炉温、气化炉反应热区下移等方面进行分析研究。

Effect of H2 addition on process of primary slag formation in cohesive zone

Based on the technology of gas-injection blast furnace(BF),the characteristics of primary slag formation with H2 addition were researched.The results indicate that,compared with traditional BF,the primary melt is formed at a lower temperature,which promotes the deformation of the solid burden particles.With the increase in temperature and H2 content,the quantity of formed melt containing FeO decreases sharply,corresponding to the crystallization of solid 2CaO Si02 during reduction.A wider softening range and narrower melting zone could be found in the gas-injection BF with a higher reduction potential.The permeability of burden layer is ameliorated as a result of decreased melt quantity.The influence of H2 on the high-temperature properties of burden is not so conspicuous when the H2 addition is from 10 to 15 vol.%against 5 to 10 vol.%.What is more,the slag shows a better liquidity with the decrease in basicity,owing to the transformation of melt composition from a primary phase field with high melting point to that with low melting point.The process of slag forming in gas-injection BF is characterized by earlier melt formation,less primary slag,higher melting temperature,better permeability and better liquidity,and the phase compositions of primary slag are close to those of final slag.

Primary slag formation behavior during reduction process of SFCA-I and SFCA

Because the formation behavior of primary slag which decomposed from complex calcium ferrite(SFCA-I and SFCA)is not quite clear,the migration behavior of CaO and Al_(2)O_(3) derived from high basicity or high alumina sinter is always worth studying.The reducibility of three representative sinter samples and the formation behavior of primary slag during reduction process were investigated via X-ray diffraction,scanning electron microscopy,and energy-dispersive spectroscopy characterization.The results show that the reducibility of high basicity sinter is superior to that of high alumina sinter.Minerals with poor reducibility like hercynite and brownmillerite and with large-grained particles like free alumina and silica form in sinters with basicity of 2.4 and Al_(2)O_(3) content of 4 wt.%,respectively.The appearance of these minerals can well explain the reduction stagnation phenomenon occurring in these sinter samples.The migration behavior of CaO and Al_(2)O_(3) during slag formation process is different.CaO can easily combine with SiO2 to form silicate phase or firstly form calcium-rich ferro-aluminate solid solution and then transform to silicate phase,while Al_(2)O_(3) firstly combines with CaO and FeO to form solid solution and then,gradually combines with SiO2 to form calcium aluminum silicate phase.

炉渣成份对无机矿物纤维指标影响情况试验研究

电炉冶炼煤矸石与红土镍矿制取无机矿物纤维的炉渣成份要求范围为:SiO_(2)(40%~48%),Al_(2)O_(3)(10%~12%),CaO(8%~18%),MgO(6%~12%),Fe_(2)O_(3)(4%~8%)。通过试验,探讨研究了炉渣主要成分调整对纤维指标的影响,确定了上述无机矿物纤维成分要求的合理性,并给出了相应成分条件下不能成纤的极限值,为行业推广提供一定的借鉴。

高炉喷吹煤气对成渣过程的影响

向高炉喷吹富氢煤气代替喷煤对高炉成渣过程产生重要的影响。对喷吹煤气后高炉的成渣过程进行了模拟研究,结果表明:FeO的含量决定了初渣的性能。在炉腹区域,氢气具有很强的还原能力,渣中FeO含量迅速减少,但同时炉渣成分快速接近终渣成分,使炉腹渣仍具有较好的熔化性和流动性。由于没有未燃煤粉和煤粉灰分的加入,初渣到终渣的成分变化较小,改善了喷煤气高炉的成渣过程。

煤气化飞灰特性的研究进展

在对煤气化飞灰的物理化学性质、微观形貌、气化反应活性和粘附特性归纳分析的基础上,讨论了气化飞灰的形成机理及其气化过程中的结渣倾向性,并对气化过程中避免飞灰在气化炉内的结渣和在合成气冷却器积灰结垢的措施进行了介绍。最后对气化飞灰的研究热点问题进行了展望。

提高第二界面固井质量的钻井液与前置液研究

针对提高第二界面固井质量的问题,研究出了多功能钻井液和SF-1冲洗前置液。对这两种体系的性能评价表明:加入矿渣后多功能钻井液的滤失量大大降低,泥饼的胶结强度提高,从而降低了钻井液对地层的损害;加有活性组分的SF-1前置液具有较强的稀释钻井液、降低粘度和切力的作用,提高了钻井液和水泥浆的相容性。现场应用表明,多功能钻井液须与MTC固井液配合使用,才具有提高第二界面固井质量的效果;SF-1前置液改善了水泥环与套管和水泥环与井壁的胶结环境,增强胶结力,提高了水泥浆的顶替效率,有效地提高了固井质量。密度介于钻井液与水泥浆之间的加重前置液在现场使用效果良好,固井质量优质,钻井液与水泥浆界面清晰。

煤气化灰渣组成结构及分选加工研究进展

煤炭气化是我国煤化工产业发展的龙头技术。随着煤化工产业的蓬勃发展,煤炭气化灰渣量增速巨大。目前,煤炭气化灰渣主要以堆积填埋方式处理为主。这不仅增加了企业的处理和运输成本,同时,造成了土地资源的极大浪费,以及水体、土壤等严重污染。因此,迫切需要突破煤炭气化灰渣的清洁高效分质利用技术瓶颈。文中针对制约煤炭气化灰渣清洁高效利用的关键科学问题,以煤炭气化灰渣的组成结构与分选加工利用为主线,重点分析了煤炭气化灰渣的组成结构及其影响因素,以及形成机理等。在此基础上,对煤炭气化灰渣精细分选加工利用,特别是残炭与玻璃微珠的分选技术进行了重点讨论。最后,对未来煤炭气化灰渣的基础与应用研究趋势进行了展望。

晶化温度对硅渣微晶玻璃形成机理和性能的影响

本文以硅渣为主要原料,利用熔融法制备了高强度微晶玻璃。采用差热分析(DTA)、X射线衍射(XRD)和扫描电镜(SEM)研究了不同晶化温度对硅渣微晶玻璃的晶相演变、显微结构、形成机理和样品性能的影响规律。研究结果表明:在最佳晶化温度870℃时,主晶相为铁板钛矿(Fe2TiO5)和透辉石(CaMgSi2O6)复合晶相,微观结构致密,晶粒呈球状,抗折强度为270MPa,维氏显微硬度为989.72MPa,耐化学腐蚀性能较好。

大型转炉低硅铁水炼钢研究

针对转炉低硅铁水炼钢成渣困难,渣量少不利于脱磷,容易产生粘枪、粘烟罩等问题,在吹炼过程中加入适量熔剂,枪位稍高于正常含硅铁水炼钢,设计化渣效果好、喷溅少的多孔喷头。低硅铁水炼钢化学热减少,可减少矿石、废钢用量,保证熔池金属正常的升温速度。低硅铁水炼钢可以实现少渣炼钢,有利于减少石灰消耗和提高金属收得率。

基于水动力条件的矿山泥石流成因与特征——以石棉县后沟为例

四川省石棉县后沟是一条典型的高频矿山泥石流沟,坡面矿渣面蚀、沟道矿渣揭底和沟口尾矿侧蚀溃决是泥石流发生的三种主要成因。水动力条件通过对矿渣提供方式的影响而导致矿山泥石流在成因、规模等方面的差异。计算表明,单纯洪水难以对后沟尾矿库稳定性构成威胁,<10a一遇泥石流主要由坡面矿渣面蚀和沟道矿渣揭底引发,流量<79m3/s,沟口尾矿库基本不参与泥石流活动,泥石流规模以小型为主;10a一遇和更大规模泥石流开始侧蚀尾矿坝,尾矿失稳垮塌补给泥石流,泥石流规模以中型甚至大型为主;后沟矿山泥石流特征主要表现为物源补给的集中性与固定性,形成过程的易发性与频发性,运动过程的单调性与重复性,成灾过程的相互性与链式性以及防治过程的可控性与多元性五个方面。