钼尾矿陶瓷透水砖的制备及性能研究

以钼尾矿为主要原料,配以适量的高温粘结剂,采用模压成型法制备陶瓷透水砖。实验结果表明:钼尾矿用量、烧成温度、保温时间,成型压力等对样品的抗折强度、抗压强度、透水系数、保水性、耐磨性、抗冻性等性能有明显的影响。实验得到的最佳工艺条件为:钼尾矿用量75%,在烧结温度1160℃,保温时间40 min,成型压力15 MPa,在此工艺条件下,得透水砖的抗折强度为3.8 MPa;抗压强度33.2 MPa,透水系数1.5×10~(-2) cm/s,保水性0.92 g/cm~2,抗磨长度27 mm,强度损失率15.3%,主要性能指标完全符合GB/T25993-2010要求。研究成果为钼尾矿的综合利用提供了一条新途径。     

煤矸石-粉煤灰烧结砖的研制

利用煤矸石和粉煤灰烧结砖不但可减少固体废弃物的排放,还可创造可观的经济效益.利用阜新本地煤矸石和粉煤灰,经原料制备、原材料的处理、砖坯成型和烧结等工艺,可生产出满足国家质量标准的烧结砖.经制备工艺正交试验,制品抗压强度主要受材料配比和烧结温度的影响,其次是升温速率和保温时间.由于助熔剂的加入,煤矸石-粉煤灰砖的焙烧温度可以由1200℃降低到1100～1150℃.由试验分析的结果,合理的材料配比为:灰矸比3∶7,外加2％玻璃粉;合理的砖坯成型水分为12％,砖坯成型压力为30 MPa;合理的烧成制度为:升温速率80min/h,烧成温度1150℃,保温时间100 min.研制的烧结砖呈粉红色至砖红色,与普通粘土砖基本相同,外观规整,无裂纹其它大的缺陷且无石灰爆裂现象.产品从制坯到烧成的过程中各方向的变形均满足质量要求.本文研究为普通黏土烧结砖厂技改成煤矸石-粉煤灰砖厂提供了有力的技术保障.     

高镁质铁尾矿制备镁橄榄石耐火材料试验研究

以河北省某高镁质铁尾矿为原料，经预先煅烧、熟料细磨后掺加少量轻烧镁砂和电熔镁砂，采用模压成型、高温烧结等工艺制备镁橄榄石耐火材料。采用正交试验探讨了铁尾矿熟料细磨时间、粘结剂乙二醇溶解酚醛树脂用量、成型压力、最高烧结温度、保温时间对烧结样品的体积密度、常温抗压强度和荷重软化温度的影响，并优化了工艺参数，结果表明：在铁尾矿熟料细磨15 min、粘结剂用量为8%、等静压成型压力为130 MPa、最高烧结温度为1 500℃、保温时间为6 h的最佳工艺条件下，得到的烧结样品体积密度为2.80 g/cm³、常温抗压强度为50.7 MPa、荷重软化温度为1 685℃、抗热震性为10次，主晶相为镁橄榄石，次晶相为方镁石，另含少量尖晶石。研究成果可为此类铁尾矿的综合利用提供技术支撑。     

铝矾土尾矿基陶瓷透水砖的制备及其性能研究

利用尾矿和工业固废采用"两步煅烧法"制备生态陶瓷透水砖.结果表明:以铝矾土尾矿为主要原料,破碎球磨后造粒并煅烧制备高强骨料,加入适量高温粘结剂.在铝矾土尾矿为85 wt％、花岗岩废料8 wt％、氟化钙污泥3 wt％、成型压力10 MPa、烧成温度1140℃、保温时间2 h条件下制备透水砖.其体积密度为1.95 g/cm...     

保温时间对高掺量粉煤灰烧结砖显微结构及性能的影响

利用XRD、SEM等测试手段 ,研究了不同保温时间对各种掺量的粉煤灰烧结砖的显微结构及性能的影响。结果表明 ,在 10 5 0℃下烧成 ,粉煤灰掺量为 5 0 %保温 5h的烧结砖性能最佳 ,而在同样温度下烧成 ,粉煤灰掺量为 80 %的烧结砖的最佳保温时间为 8h。在适宜保温时间下 ,烧结砖中孔隙少且不连通 ,显微结构均匀     

石煤提钒尾矿制备烧结砖的研究

以陕南地区的石煤直接浸出提钒尾矿为主要原料,掺加当地的粘土制备建筑烧成用砖,考察粘土掺量及烧成温度对烧结制品性能的影响.结果表明:在尾矿颗粒料、粘土、尾矿细粉比为65∶15∶20,成型水分为8％,采用干压成型,在1000℃下保温3h可以制得烧结砖.制得的试样体积密度为1.82 g/cm3,吸水率为16.1％,抗压强度为14 MPa,达到《烧结普通砖》(GB/T5101-2003)中MU10的规定.尾矿利用率可以达到85％.     

零价铁颗粒吸附材料的制备及其性能研究

以粉煤灰为骨料,浒苔为造孔剂,膨润土为粘结剂,利用焦炭还原粉末状铁尾矿的方法制备成一种含零价铁的颗粒吸附材料(ZVI-GAM)。研究了单因素对ZVI-GAM性能的影响,以及通过正交试验得出材料的最佳制备条件,并对其结构及性能进行了表征。吸附材料的最佳制备条件为:烧结温度为900℃,烧结时间为90 min,升温速率为10℃/min,粉煤灰、膨润土、焦炭、铁尾矿的质量比为1∶2∶2∶2,浒苔的添加量为1%,浒苔的粒径为过60目筛。在温度为30℃、龙胆紫初始质量浓度为2 000 mg/L的条件下, ZVI-GAM对龙胆紫的去除量为240mg/g。ZVI-GAM对龙胆紫的去除主要包括吸附和还原作用。     

煤矸石提铝提硅废液对烧结砖性能的影响研究

以煤矸石、粉煤灰和煤矸石提铝提硅废液为主要原料制备烧结砖,研究废液掺量对烧结砖抗压性能的影响。结果表明,不掺加废液时,烧结砖的最佳配方为:煤矸石80%,粉煤灰20%,水固比为15%,烧结砖的抗压强度为29.78 MPa;废液替代水的量为50%时,烧结砖的抗压强度为24.97 MPa,满足MU20等级的要求。     

双氧水发泡法制备泡沫陶瓷外墙保温板

本文以粉煤灰和铜尾矿为主要原料,掺加膨润土和赤泥,以长石为助熔剂,双氧水为发泡剂,聚乙烯醇为稳泡剂,采用浆料发泡烧结法制备泡沫陶瓷外墙保温板.确定了适宜的原料组成为粉煤灰40％％铜尾矿38％％长石10％％膨润土10％％赤泥2％％双氧水的加入量为5％％所制备的泡沫陶瓷的性能为:吸水率0.90％％体积密度1.10g/cm3、显气孔率为0.70％％抗压强度为8MPa、导热系数为0.15 W/m·k.     

温度制度对尾矿烧结砖性能及结构的影响

以鄂西赤铁矿尾矿为主要原料制备烧结砖,研究了升温速率、烧成温度和保温时间对样品的性能、相组成以及显微结构的影响.结果表明:烧成温度和保温时间是影响样品性能和结构的主要因素,升温速率从2 ℃/min到10 ℃/min变化对砖体性能影响不大.XRD和SEM分析表明:新的结晶相α-鳞石英、钙铝黄长石和钙长石在1000 ℃左右开始形成,同尾矿中原有的α-石英和赤铁矿等晶相一起构成烧结砖的矿物骨架,赋予其强度;液相量随着烧成温度的提高不断增多,晶体颗粒被熔融的玻璃质所包裹胶结形成整体,有利于强度的提高和吸水率的降低.最适宜的温度制度为升温速率6 ℃/min左右、烧成温度980～1030 ℃、烧成保温时间2～3 h,在此条件下烧制的尾矿烧结砖各项性能均达到<烧结普通砖>(GB/T5101-2003)中MU20的要求.     

利用提钒尾渣制备烧结广场砖实验研究

以提钒尾渣为主要原料,采用半干法成型方法制备烧结广场砖,通过添加广西白泥、硅铁灰、粉煤灰和A12O3粉可以优化提钒尾渣烧结广场砖的物理指标,提高烧结广场砖的性能.通过条件试验较系统研究了广西白泥配入量、粉煤灰、硅铁灰和A12O3粉配入量对烧结广场砖常温耐压强度和吸水率的影响.条件试验表明:广西白泥配入量为20%左右较适宜、硅铁灰配入量控制在5%以内较适宜、粉煤灰配入量控制在6%以内较适宜、Al2O3粉添加量控制在8%以内较适宜.制得提钒尾渣广场砖的常温耐压强度达到28 MPa以上,吸水率可以降低到10%左右.     

Preparation of high-strength ceramsite from red mud,fly ash,and bentonite

High-strength ceramsite was prepared from red mud, fly ash, and bentonite without any other chemical additives by a two-stage sintering process. In addition, the raw material weight ratio, and sintering condition (sintering temperature, sintering time, preheating temperature, and preheating time) were investigated, and their effects on the ceramsite properties were determined. The mineral compositions, crystalline phases, microstructures, and hazardous substances solidification were determined by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. Under the optimal synthetic conditions (RM:fly ash:bentonite = 60:30:10, preheating temperature of 450 °C, preheating time of 10 min, sintering temperature of 1150 °C, and sintering time of 25min), the ceramsite exhibited a high compressive strength of 21.01 MPa, 1-h water absorption of 1.21%, and bulk density and apparent density were 994 and 1814 kg/m³, respectively. Furthermore, the concentrations of toxic substances leaching from the ceramsite were considerably lower than the Chinese national standard (GB 3838-2002), which implies that RM-based ceramsite cannot cause secondary environmental pollution. The prepared ceramsite exhibiting a high compressive strength, low water absorption, and effective solidification of deleterious elements can be used to prepare building concrete and lightweight partition boards. Importantly, the reuse of RM for the production of ceramsite is an effective approach for the disposal of harmful RM.     

Preparation and properties of anorthite-based ceramics by using metallurgical solid waste and fly ash

A large amount of metallurgical solid waste accumulation poses a serious threat to the environment. Study on synergistic reinforcement of synthetic process of metallurgical solid waste-based ceramics with fly ash is of great significance in reducing environmental pollution and resource utilization. A metallurgical solid waste-based ceramic used as building ceramic was developed with the erosion part of used MgO–C bricks and fly ash as main raw materials, and the amount of solid waste added to the prepared ceramics was at least 60 wt% and up to 90 wt%. The effects of fly ash content and sintering temperature on the crystalline phase transitions, morphologies, and the main physical and mechanical properties of ceramics were investigated by X-ray diffraction, scanning electron microscopy, and mechanical testing. The results show that the obtained ceramics presented maximum bending strength and minimum water absorption, 80.14 MPa and 5.04%, respectively, when the raw material proportions were the erosion part of used refractories accounted for 60 wt%, fly ash 20 wt%, pyrophyllite 10 wt%, and quartz sands 10 wt%, and the process parameters were the sintering temperature 1150°C, sintering time 120 min, and molding pressure 15 MPa.     

氮化硅陶瓷的无压烧结工艺优化及性能研究

以α-Si3 N4为原料,Y2 O3和MgO为复合烧结助剂,通过无压烧结制备出氮化硅陶瓷。为了优化实验配方和工艺参数,采用正交实验研究了成型压力、保压时间、保温时间、烧结温度、烧结助剂含量以及配比对氮化硅陶瓷气孔率和抗弯强度的影响规律。结果表明,影响氮化硅陶瓷气孔率的主要因素是烧结助剂含量和配比,而影响其抗弯强度的主要因素是烧结助剂配比和烧结温度。经分析得出,最佳工艺参数为成型压力16 MPa,保压时间120 s,保温时间2 h,烧结温度1750℃,烧结助剂含量12wt％,烧结助剂配比1∶1;经最佳工艺烧结后的氮化硅陶瓷,相对密度为94．53％,气孔率为1．09％,抗弯强度为410．73 MPa。     

烧结制度及造孔剂用量对粉煤灰基多孔陶瓷膜支撑体性能的影响

以粉煤灰为原料,采用挤压成型和固态粒子烧结法制备管状粉煤灰基多孔陶瓷膜支撑体.采用TG-DSC技术对粉煤灰进行了热分析,采用SEM和XRD技术对样品的微观结构及物相组成进行了分析,并测定了样品的开孔率、抗压强度及空气渗透速率等性能指标.研究了烧结温度、保温时间和造孔剂添加量对支撑体性能的影响.结果表明:支撑体晶相组成主要为赤铁矿、红柱石和石英;烧结温度为1000 ℃,保温2 h,仅添加1%的粘结剂,不添加造孔剂的条件下制备出的管状支撑体综合性能最优,此时的支撑体孔隙率为44.95%,抗压强度为8.92 MPa,空气渗透速率为2.57×104 m3·h-1·m-2·MPa-1.     

Recycling of harmful waste lead-zinc mine tailings and fly ash for preparation of inorganic porous ceramics

The porous ceramics were prepared by directly sintering of lead-zinc mine tailings and fly ash as the raw materials without any additional sintering and foaming agent. The effects of fly ash addition on the crystalline phases, pore structure, physical–chemical porosities and mechanical strength were investigated. The results showed that the bulk density decreased firstly and then increased while the porosity and water absorption presented the opposite tendency with the increase of fly ash content. Meanwhile, the chemical stability improved and the flexural strength had the same variation tendency of the bulk density. The phase evolution of sample with 60 wt% fly ash addition indicated that anorthite phase was formed at low temperature (1000 °C). The thermal behavior illustrated that the foaming process was initiated by the reaction of internal constituents in the lead-zinc mine tailings. Different pore structures indicated different foaming mechanisms that probably occurred at different temperatures. The porous ceramics with 60 wt% fly ash addition exhibited excellent properties, including bulk density of 0.93 g/cm³, porosity of 65.6%, and flexural strength of 11.9 MPa.     

利用城市垃圾焚烧飞灰研制阿利尼特水泥熟料

以城市垃圾焚烧飞灰(以下简称焚烧飞灰)为主要原料,在实验室电炉里成功烧成了阿利尼特水泥熟料,分析了熟料烧成所需适宜的生料组成和最佳煅烧温度,并研究了石膏掺量对阿利尼特水泥强度影响,以及阿利尼特水泥的标准稠度用水量和凝结时间.结果表明:以焚烧飞灰为主要原料合成阿利尼特水泥熟料无需外掺MgO;较适宜的生料化学组成为CaO 55%～59%,SiO2 17%～20%,Al2O3 3%～5%-MgO 0.5%～3%,Cl 8%～10%最佳煅烧温度为1200℃;添加适量石膏有助于提高阿利尼特水泥早期抗压强度;阿利尼特水泥较硅酸盐水泥有较低的标准稠度用水量和较短的凝结时间.     

堇青石多孔陶瓷的制备与性能表征

以粉煤灰和碱式碳酸镁为主要原料制得了堇青石多孔陶瓷材料.烧结温度在1 100～1 350℃时,样品的弯曲强度由50 MPa增加至65 MPa,热膨胀系数由8.07×10-6℃-1下降至4.21×10-6℃-1.优化的烧结工艺为1 300℃保温4 h.样品的孔隙率和孔径随原料中淀粉含量的增加而增加.在原料中添加40%(质量分数)的造孔剂(淀粉)可使样品的孔隙率、平均孔径为和氮气通量分别达到41.7%,2.35μm和0.225 m·h-1Pa-1.     

Preparation of high strength and low thermal conductivity mullite refractories based on reconstruction of fly ash

The preparation of refractories with both low thermal conductivity and high strength are continuously pursued in industrial furnaces. In this work, mullite refractories with low thermal conductivity and high strength were developed using fly ash as main raw material, and the influence of the quantity of fly ash and sintering temperature on the structure and properties of mullite refractories were investigated. The results show that mullite refractories with low thermal conductivity and high strength could be prepared by using fly ash in large proportion; the thermal conductivity of the samples decreased with the addition of the fly ash and increased with the increase of sintering temperature; the cold compressive strength and modulus of rupture of samples all are enhanced with the increase of sintering temperature, which is attributed to the formation of more elongated mullite by the reconstruction of fly ash at high temperature. For the mullite refractory using 65.04 wt% fly ash treated at 1600°C, the thermal conductivity was .732W/(m·k) at 1000°C, and the cold compressive strength and modulus of rupture could reach 143.5 ± 5.7 MPa and 47.0 ± 4.1 MPa respectively. It can be considered to use as a prospective work lining in industrial furnaces to meet energy saving requirements.     

Preparation and characterization of porous anorthite ceramics from red mud and fly ash

The porous anorthite ceramics with high porosity, good mechanical strength and low heat conductivity were prepared using red mud and fly ash as raw materials via the pore forming method. The effects of sintering temperature and fly ash on phase evolution, densification, compressive strength, thermal conductivity and microstructure of the ceramic materials were investigated. The results showed that the compressive strength of the porous ceramics had an obvious improvement with the increase in fly ash, and the densification and heat conductivity decreased firstly and then increased. In particular, specimen S2 containing 30 wt% red mud and 40 wt% fly ash sintered at 1150°C had the better performances. It had the water absorption of 18.18%, open porosity of 38.52%, bulk density of 1.29 g/cm³, compressive strength of 42.46 MPa, and heat conductivity of 1.24 W/m·K. X-ray diffraction analysis indicated that mullite, anorthite, α-quartz, and diopside ferrian were the dominant phases in the specimens. Scanning electron microscopy micrographs illustrated that plenty of open pores with strip shape and closed pores with axiolitic shape existed in the specimens. Furthermore, the existence of mullite could prevent crack propagation to enhance the energy of inter-granular fracture. It endowed the porous anorthite ceramics with high porosity, good compressive strength, and low heat conductivity.