碳酸钙对磷渣-煤矸石烧结多孔微晶玻璃结构和性能的影响

多孔微晶玻璃具有导热系数低、力学性能好、抗腐蚀性强等优点,是一种隔热、吸声的轻质功能材料.为拓展多孔微晶玻璃的制备原料范围,同时大宗量、高附加值利用工业废渣-磷渣和煤矸石.本文以磷渣和煤矸石为原料,采用烧结法制备多孔微晶玻璃.利用X射线衍射、扫描电子显微镜及阿基米德法,对制备的试样进行表征,研究发泡剂碳酸钙掺量对体系析...     

矿渣微晶玻璃研究与进展

回顾了矿渣微晶玻璃的研究历史，着重分析了不同主晶相的矿渣微晶玻璃的组成，结构与性能，对矿渣微晶玻璃的发展趋势和待解决的问题作了探讨。最后评述了我国在矿渣微晶玻璃开发与应用上与国外的差距。     

熔制保温时间对CAMS系矿渣微晶玻璃结构与性能的影响

以白云鄂博二次选后尾矿、高炉渣和粉煤灰为主要原料,采用熔融法制得CaO-Al_2O_3-MgO-SiO_2(CAMS)系微晶玻璃,利用DSC、XRD、SEM、EDS、Raman、红外光谱及理化性能测试手段,研究了熔制过程中不同保温时间对微晶玻璃结构与性能的影响。结果表明:随着熔制保温时间的延长,矿渣玻璃熔液中氟的挥发及对氧化铝坩埚的侵蚀导致基础玻璃中氟含量降低而Al2O3含量升高,基础玻璃析晶温度呈先上升后下降的趋势,微晶玻璃主晶相为透辉石,晶粒出现先细化后粗化的趋势,第二相萤石相随着保温时间的延长逐渐消失,最终导致微晶玻璃结构及理化性能发生改变。当玻璃熔制保温时间为5h时,制备的微晶玻璃综合性能最优,其密度、抗折强度、显微硬度及耐酸碱性分别为3.09g/cm3、201 MPa、7 021 MPa、97.78%和98.83%。     

赤泥-粉煤灰微晶玻璃晶化行为研究

综合利用赤泥和粉煤灰两种废渣制备高附加值的微晶玻璃材料,两种废渣总吃渣量能够达到90wt%以上,降低了生产成本.对不同核化温度、晶化温度对微晶玻璃显微组织的影响进行了研究.结果表明:最佳核化温度由基础玻璃的DTA曲线的吸热峰确定,大约697℃;最佳的晶化温度略高于DTA析晶峰的温度,大约为950℃.     

铜冶炼渣制备建筑材料及功能材料的研究进展

铜是现代工业中不可或缺的基础材料,作为世界上最大的精炼铜生产国,我国每年产出近2 000万t铜冶炼渣(以下简称铜渣)。虽然铜渣中含有大量有价金属,但因其综合利用率极低,绝大部分的铜渣露天堆积,占用大量土地。此外,铜渣中含有不可生物降解性的砷、铅等剧毒物质,在堆积过程中会浸入土壤、流入江河,在生物体内积累,导致许多疾病与健康隐患。如何利用铜渣缓解矿产资源压力,实现经济与环境共赢,已成为当下迫切需要处理的难题。铜渣富含铁和硅元素,主要由铁硅酸盐和磁铁矿相组成,提取和分离其中的铜、铁等有价元素的工艺不仅能耗高,也达不到无害化和减量化处理的目的。而铜渣能够直接、完全应用于建筑材料的制备,可获得相应高性能的材料,工艺过程环保,是铜渣清洁利用的首选方案。用铜渣取代天然矿物制备的铜渣微晶玻璃与矿渣棉不仅具有与传统微晶玻璃、矿棉相似甚至更优的性能,而且能够减少环境污染,降低工业成本,实现废渣高附加值再利用,具有广阔的市场前景。此外,虽然铜渣在建筑、功能材料等领域的应用研究取得了显著成效,但也存在一些不足之处需要进一步研究。例如,利用铜渣制备混凝土时,需要对铜渣的活性进行激发,但物理激发因经济因素导致效果有限,而化学激发不能应用于大规模工程;铜渣制备出的微晶玻璃产品质量不稳定、成品率低、色调单一,不能满足市场需求;铜渣成分复杂且差异较大,严重影响水泥混凝土、微晶玻璃的性能可控性。本文综述了不同炼铜工艺所产生的铜渣的物相特征及物理性质,分析了利用选矿及物理化学方法提取铜渣中铜、铁有价金属过程存在的问题,介绍了铜渣直接用于水泥、混凝土、沥青路面等建筑材料以及微晶玻璃、矿渣棉、磨料等功能材料方面的应用研究现状,剖析了铜渣在制备建筑、功能材料方面的清洁工艺中存在的问题和缺陷,并展望了其应用与研究方向。     

β-锂霞石负膨胀微晶玻璃的制备技术及结构特征

研究了β锂霞石微晶玻璃的制备技术、结构特征及其负膨胀特征。首先采用玻璃结晶法制备β锂霞石负膨胀微晶玻璃材料,然后通过XRD、SEM等测试手段,表征了β锂霞石微晶玻璃材料的结构特征。并讨论β锂霞石负膨胀微晶玻璃的膨胀系数及其与晶相组成和晶化温度及时间的依从关系,使其负膨胀系数在一定范围内连续可调。研究并制备出热膨胀系数可达到为-1.037×10-5/℃的β锂霞石微晶玻璃。     

石墨粉对矿渣微晶玻璃结构和性能的影响

用熔铸法、以白云鄂博东尾矿及粉煤灰为主要原料制备了添加质量分数为0-13%石墨粉的CaO-Al2O3-MgO-SiO2(CAMS)系矿渣微晶玻璃,用DTA、XRD、FE-SEM、TEM和热膨胀仪等手段对其表征,研究了石墨粉添加量对CAMS基矿渣微晶玻璃结构和性能的影响。结果表明,5%石墨粉被氧化提高Fe2+含量促进了辉石相的晶化,样品在100-600℃的热膨胀系数可提高15%以上;随着Fe被更多的石墨粉还原出来,辉石相形核基础-磁铁矿相晶核减少抑制了辉石相的生成。辉石球形晶粒由尺寸更小的柱状晶和少量残留玻璃相组成。     

新型陶瓷粉/冶炼渣微晶泡沫玻璃研制

以冶炼渣为主要原料,配比一定比例陶瓷废料调质,采用"一步法"粉末烧结法制备新型微晶泡沫玻璃。以控制变量法研究不同掺量的Na₂CO₃对微晶泡沫玻璃的影响;结合DSC、XRD、TOM-ac等现代分析测试技术,分析微晶泡沫玻璃样品气孔结构、玻璃物相组成、样品烧结过程中形貌体积变化,优化研制配方。该实验过程中所制备的微晶泡沫玻璃的晶相以硅灰石Ca₃Si₃O₉与次透辉石CaFe(Si₂O₆)为主,其抗压强度可达到13.06 MPa,密度为0.731 g/cm³。制备得到泡沫微晶玻璃集中了微晶玻璃和泡沬玻璃的优点,具有机械强度高、密度小、热膨胀系数小、化学稳定性优良等特点,既解决了污染环境、资源浪费等问题,同时在建筑等行业具有广泛的应用价值,为冶炼渣的综合利用提供了新的途径。     

Nb2O5对透辉石基矿渣微晶玻璃显微结构和力学性能的影响

为研究Nb_2O_5对透辉石基矿渣微晶玻璃显微结构和力学性能的影响机理,以富铁白云鄂博西尾矿、粉煤灰为主要原料,采用熔融工艺制备了添加质量分数0%~4%Nb_2O_5的透辉石基矿渣微晶玻璃。DTA、XRD、SEM和力学测试结果表明,Nb_2O_5主要以Ca2Nb2O7第二相的形式存在于辉石相界,其含量随Nb_2O_5添加量升高而增大。同时辉石主晶相从类菊花状枝晶组织转变成平均尺寸逐渐减小的圆角岛状组织。微晶玻璃的抗折强度平均为207 MPa,当Nb_2O_5质量分数为2%时最高,达236 MPa。     

高炉矿渣二次资源合成绿色无机材料的研究进展

以高炉矿渣为原料合成绿色无机材料,不仅为固体废弃物的深度利用提供了一条新的思路,而且为多种无机材料的廉价合成提供了一条新的绿色工艺.在简单介绍高炉矿渣矿物及化学组成的基础上,综述了利用高炉矿渣二次资源合成Sialon、水泥及混凝土、涂料、胶凝材料、矿渣纤维、硅灰石、多孔陶粒、泡沫材料、微晶玻璃、透水砖等绿色无机材料的研究进展,并对其发展前景进行了展望.     

CAS系粉煤灰微晶玻璃制备工艺试验研究

以工业废弃物粉煤灰为主要原料,详细介绍了采用烧结法制备CaO-Al2O3-SiO2系粉煤灰微晶玻璃的过程及工艺细节。运用差热分析（DTA）、X射线衍射（XRD）、扫描电镜（SEM）等技术对粉煤灰微晶玻璃进行了研究,并测试了粉煤灰微晶玻璃的物化力学性能。通过实验分析了粘结剂用量与压力在微晶玻璃试样成型过程中的影响。检测结果表明,粉煤灰微晶玻璃的主晶相为副硅灰石,副晶相为钙长石;在粘结剂掺量为20%,并在20MPa的压力下成型所制得的微晶玻璃性能最优。     

Glass-ceramics: Their production from wastes—A Review

Glass-ceramics are polycrystalline materials of fine microstructure that are produced by the controlled crystallisation (devitrification) of a glass. Numerous silicate based wastes, such as coal combustion ash, slag from steel production, fly ash and filter dusts from waste incinerators, mud from metal hydrometallurgy, different types of sludge as well as glass cullet or mixtures of them have been considered for the production of glass-ceramics. Developments of glass-ceramics from waste using different processing methods are described comprehensively in this review, covering R&D work carried out worldwide in the last 40 years. Properties and applications of the different glass-ceramics produced are discussed. The review reveals that considerable knowledge and expertise has been accumulated on the process of transformation of silicate waste into useful glass-ceramic products. These glass-ceramics are attractive as building materials for usage as construction and architectural components or for other specialised technical applications requiring a combination of suitable thermo-mechanical properties. Previous attempts to commercialise glass-ceramics from waste and to scale-up production for industrial exploitation are also discussed.     

Sintering of MSWI fly ash by microwave energy

This study presents the sintering of municipal solid waste incineration (MSWI) fly ash assisted by microwave energy. The composition of fly ash was investigated by chemical sequential extraction and modified microwave digestion method. Effects of process time, container materials, aging time and salt contents were also discussed. The major elements of fly ash are Ca, Cl, Na, Si, K, Al, Mg, and Zn, and the metal species, Zn, Cr, Pb, Ca, and Cu, are mainly in the oxide phase. Under microwave processing, the fly ash was sintered into a glass-ceramics and the leaching concentrations of heavy metals were restrained. The stabilization efficiency increased with an increase in processing time in most of the cases. Better stabilization efficiency of fly ash was discovered by using the SiO(2) or Al(2)O(3) container than by using the graphite plate/SiC plate. The presence of salt in the fly ash could enhance the sintering and stabilization of fly ash. During the aging time of 0-30 days, negligible Pb in the sintered fly ash was leached out, and the leaching concentration was lower than the criterion.     

Utilization of municipal solid waste incineration ash in Portland cement clinker

Municipal solid waste incineration (MSWI) ash is used in part as raw materials for cement clinker production by taking advantage of the high contents of SiO₂, Al₂O₃, and CaO. It is necessary for environmental reasons to establish a material utilization system for the incineration waste ash residue instead of disposing these ashes into landfill. The aim of this paper is to study the feasibility of replacing clinker raw materials by waste ash residue for cement clinker production. MSWI bottom ash and MSWI fly ash are the main types of ashes being evaluated. The ashes were mixed into raw mixture with different portions of ash residue to produce cement clinker in a laboratory furnace at approximately 1400°C. X-ray diffraction and X-ray florescence techniques were used to analyze the phase chemistry and chemical composition of clinkers in order to compare these ash-based clinkers with commercial Portland cement clinker.     

Chromium behavior during thermal treatment of MSW fly ash.

Energy-from-waste incineration has been promoted as an environmentally responsible method for handling non-recyclable waste from households. Despite the benefits of energy production, elimination of organic residues and reduction of volume of waste to be landfilled, there is concern about fly ash disposal. Fly ash from an incinerator contains toxic species such as Pb, Zn, Cd and Cr which may leach into soil and ground water if landfilled.Thermal treatment of the fly ash from municipal solid waste has been tested and proposed as a treatment option for removal of metal species such as Pb, Cd and Zn, via thermal re-volatilization. However, Cr is an element that remains in the residue of the heat treated fly ash and appears to become more soluble. This Cr solubilization is of concern if it exceeds the regulatory limit for hazardous waste. Hence, this unexpected behavior of Cr was investigated. The initial work involved microscopic characterization of Cr in untreated and thermally-treated MSW fly ash. This was followed by determining leaching characteristics using standard protocol leaching tests and characterization leaching methods (sequential extraction). Finally, a mechanism explaining the increased solubilization was proposed and tested by reactions of synthetic chemicals.     

Use of fly ash,phosphogypsum and red mud as a liner material for the disposal of hazardous zinc leach residue waste

Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The release of large quantities of heavy metals into the environment has resulted in a number of environmental problems. The present study investigated the safe disposal of the zinc leach residue waste using industrial residues such as fly ash, phosphogypsum and red mud. In the study, leachability of heavy metals from the zinc leach residue has been evaluated by mine water leaching procedure (MWLP) and toxicity characteristic leaching procedure (TCLP). Zinc removal from leachate was studied using fly ash, phosphogypsum and red mud. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudo-second-order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudo-second-order kinetic was the best fit kinetic model for the experimental data. The results show that addition of fly ash, phosphogypsum and red mud to the zinc leach residue drastically reduces the heavy metal content in the leachate and could be used as liner materials.     

Characterization of alpha-cordierite glass-ceramics from fly ash

Batches of alpha-cordierite glass-ceramics, designated as GC-I and GC-II, containing 68 and 64 wt.% fly ash, respectively, were crystallized in the temperature range of 1125-1320 degrees C. The XRD (X-ray powder diffractometer) of the glass-ceramics show that alpha-cordierite became the dominant phase in GC-I and GC-II at 1200 degrees C. GC-I and GC-II, whose solid parts contain 74 and 78 vol.% alpha-cordierite and whose compressive strengths are 35 and 50 MPa, respectively, have the respective linear thermal expansion coefficients of 1.51x10(-6) and 1.43x10(-6)/ degrees C. The fly ash alpha-cordierite glass-ceramics can be employed as kiln furniture, honeycomb substrates for catalysts, and heat exchangers.     

碱渣用作砂浆保水剂的试验研究

碱渣是氨碱法制纯碱排出的废渣,其堆存和排放造成严重的环境问题。通过对原状碱渣采取工艺处理得到较低氯离子含量的水洗碱渣和除氯碱渣,研究了原状碱渣、水洗碱渣、除氯碱渣应用于砂浆时对其性能的影响及除氯碱渣用作砂浆保水剂的可行性。结果表明,各类碱渣取代15%粉煤灰均有利于提高砂浆的保水性,但原状碱渣及水洗一次碱渣掺入砂浆后氯离子溶出含量偏高,可能造成耐久性问题;而除氯碱渣不会有耐久性问题,可以作为砂浆保水剂。除氯碱渣用作砂浆保水剂使用时,砂浆具有良好的保水性能、力学性能和较低的干缩值。其较佳的应用方式为:碱渣取代胶凝材料中的部分粉煤灰,在不改变水胶比的前提下,加入减水剂来调节砂浆稠度,无需复合有机保水剂。