烧结时间对钼尾矿掺杂低品位金红石精矿微晶玻璃性能的影响

以钼尾矿、低品位金红石精矿为原料,采用烧结法制备微晶玻璃,并测定其抗压强度、抗折强度、体积密度和化学稳定性,通过X射线衍射分析研究不同烧结时间下微晶玻璃的物相组成。结果表明：在低品位金红石精矿质量分数8%、烧结温度970℃条件下,最佳烧结时间为120 min。此条件下制备的微晶玻璃产品的抗压强度为152.5 MPa,抗折强度为81.4 MPa,体积密度为2.87 g·cm^-3,耐酸质量损失率0.19%,耐碱质量损失率0.16%。随着烧结时间的延长,微晶玻璃的析晶能力增强,析出晶体为钙长石和透辉石。研究成果对钼尾矿及低品位金红石精矿的高效利用具有一定的借鉴意义。     

烧结温度和粘结剂对锂辉石浮选尾矿陶瓷材料化学性能的影响

以建筑装饰用锂辉石浮选尾矿为主要原料,辅以碳酸锂、氧化铝、氧化钾、氧化锆、五氧化二磷、二氧化硅和氧化铁,烧结温度在1350～1425℃的范围内,常压烧结制备了锂辉石浮选尾矿陶瓷材料。结果表明,高岭土是陶瓷材料的最佳粘结剂,且在1425℃时陶瓷材料可以达到致密化程度,此时陶瓷材料的耐蚀性为20.7MPa、氧化速率小于5簇0.1mm/a、耐老化指数为55.7、热膨胀系数为16.2。研究表明,高温作用下出现了玻璃相,陶瓷材料传质作用的增强填充了内部的孔隙,提高了陶瓷材料的强度。     

锂辉石对红柱石基复相陶瓷烧结性能的影响

以红柱石、微米级PSZ(部分稳定氧化锆)、苏州土、滑石为主要原料,添加适量锂辉石,采用反应烧结法制备了红柱石基复相陶瓷。研究了锂辉石的添加量对红柱石基复相陶瓷烧结性能和力学性能的影响。利用X射线衍射仪、扫描电子显微镜以及万能试验机表征样品的物相组成、微观结构和力学性能。结果表明:在1400℃烧结温度下保温2 h获得了性能优良的红柱石基复相陶瓷,样品吸水率为0.28%,气孔率为0.74%,体积密度为2.61 g/cm~3,抗折强度达96.08 MPa;随着锂辉石添加量的增大,样品的体积密度增大。XRD、SEM分析结果表明,复相陶瓷的主晶相为莫来石和锆英石晶体,锆英石和α-方石英均布在莫来石的骨架中,提高了复相陶瓷的机械性能和断裂性能。红柱石复相陶瓷是一种有广阔应用前景的高温结构陶瓷材料。     

刚玉–莫来石–镁铝尖晶石复合陶瓷的原位合成及热震行为

以α-Al2O3、苏州土、滑石和石英为主要原料,采用无压烧结制备了刚玉–莫来石–镁铝尖晶石多相复合陶瓷,研究了烧结温度对样品的体积密度、线性收缩率和吸水率等烧结性能以及机械性能的影响。通过X射线衍射和扫描电子显微镜分析了复相陶瓷热震前后的物相组成和显微结构。结果发现：经1480℃烧结的样品吸水率为0.19%,体积密度为3.06g/cm3,抗折强度达99.59MPa,复合材料有较好的热震性能,1100℃空冷热震损失率仅6.9%,可耐受17次热冲击。该复相陶瓷可作为潜在的太阳能热发电材料。     

磷酸对硅微粉研制的多孔陶瓷的影响

以铁合金冶炼过程中产生的超细硅灰粉尘为主要原料,添加适量结合剂,经高温烧结可研制成本低廉的多孔陶瓷.本论文主要探讨不同烧结温度下以磷酸为结合剂的多孔陶瓷的气孔率、体积密度、抗折强度的变化,并采用X射线粉末衍射分析和扫描电镜对其晶相组成和微观结构进行表征.结果表明磷酸结合剂的最佳添加量为2.0%,最佳烧结温度为700℃,所制得的多孔陶瓷以无定形SiO2为主相,样品气孔率为43.55%,吸水率为34.19%,体积密度为1.25g/cm3,抗折强度为28.50MPa.     

重金属尾矿与陶瓷浆制备发泡陶瓷的工艺研究

拟利用铅锌尾矿、废陶瓷浆为原料,生产高附加值发泡陶瓷材料,实现尾矿资源的综合利用。通过设计实验,确定制备发泡陶瓷的尾矿、废陶瓷浆及各化工原料的配方,并通过显微硬度、密度测试、导热系数、吸水率、抗折抗压、耐酸碱腐蚀等分析方法,研究发泡陶瓷产品的体形貌特征及性能等。结果表明:铅锌尾矿制备发泡陶瓷的最佳配方为:废玻璃60%、尾矿20%、废陶瓷浆20%、碳化硅0.6%,其发泡均匀,能达到良好的效果。经优化的烧结制度为25~800℃,2h;800~900℃,1h;900~950℃,0.5h;950~960℃,0.5h;960℃,保温1.5h。制备的发泡陶瓷产品的平均显微硬度为10.05GPa,密度达到445kg/m3,导热系数为0.078W/(m·K),吸水率为1.25%,试样抗折强度为0.49MPa、抗压强度为1.24MPa,耐酸碱腐蚀性良好,经腐蚀后,质量变化分别为0.21%、0.59%。     

太阳能热发电莫来石-硅酸锆复相陶瓷的原位合成及性能

以红柱石、ZrO2、苏州土和长石为主要原料,采用无压烧结制备了太阳能热发电用莫来石-硅酸锆复相陶瓷.研究了烧结温度对材料吸水率和力学性能的影响,采用空冷法研究了材料的热震性能,利用X射线衍射仪和扫描电子显微镜分析了复相陶瓷热震前后的物相组成和显微结构.结果表明:在1490℃烧结的最优样品A2吸水率为0.41％,气孔率为1.10％,体积密度为3.06 g/cm3,抗折强度达128.78MPa;复合材料有很好的热震性能,1100℃空冷热震损失率上升10.69％,可耐受30次以上热冲击,该复相陶瓷可作为潜在的太阳能热发电管道材料.     

Li_2CO_3添加量对锂辉石-莫来石复相陶瓷材料性能的影响

以龙岩高岭土、锂辉石和石英为主要原料,经1200～1400℃烧成制备了锂辉石-莫来石复相陶瓷材料,并利用XRD和SEM等测试方法研究了Li_2CO_3对复相陶瓷的物相组成、显微结构及各项性能的影响。结果表明,经1320℃烧成B3配方样品(Li_2CO_3添加量为1.5 wt%)的综合性能最优(吸水率0.70%,体积密度2.13 g·cm~(-3),抗折强度48.1 MPa,热膨胀系数为2.61×10~(-6)℃~(-1))。Li_2CO_3提高锂辉石晶相含量的效果十分显著,有利于降低材料的热膨胀系数。从液相中析出的针棒状莫来石呈相互交织的形貌,赋予材料较高的抗折强度。     

以煤沥青为原料制备高性能无黏结剂炭材料

以煤沥青为原料,利用热缩聚搅拌法制备中间相原料,并对中间相原料进行预处理,以及后续的粉体制备、成型、烧结等工序制备无黏结剂炭材料。实验表明,炭粉A和树脂A的加入对中间相原料的制备有明显的催化作用,而搅拌对中间相原料的制备过程至关重要。研究还比较了不同预处理时间对中间相原料自烧结性能的影响,结果表明,氧化时间为120min的中间相原料制得的炭材料体积密度为1.61g/cm3,抗折强度为78MPa,抗压强度为152MPa。     

B_4C/Al-Mg复合材料的制备及性能研究

用模压成型法制备了B_4C/Al-Mg复合材料。采用水静力天平、抗折强度测定仪、X射线衍射仪和SEM对其物理性能、力学性能和晶体结构和微观形貌进行了分析,研究了原料配方及烧结温度对B_4C/Al-Mg复合材料的晶型转变、微观形貌、体积密度、力学性能等的影响。结果表明,当Al、Mg的配比为37.0%和3.0%,烧结温度为1150℃时复合材料的综合性能最佳,体积密度为2.40 g/cm~3,抗折强度为303.67 MPa,硬度为79.4 HRC。     

细粒黄金尾矿制备烧结砖的试验研究

为了解决细粒黄金尾矿的堆存对环境的污染和资源浪费问题,以细粒黄金尾矿为主要原料,添加膨润土、粉煤灰制备烧结砖。对原料基本成分分析后,采用模压成型法来制备烧结砖,主要研究焙烧温度、保温时间、以及物料的不同配比对烧结砖性能的影响。结果表明:最佳组成为尾矿75%(质量分数,下同),膨润土15%,粉煤灰为10%;最佳工艺条件为成型水分10%,成型压力20 MPa,焙烧温度1 175 ℃,保温时间50 min。在该条件下制备的烧结砖的抗压强度为38.71 MPa,抗折强度为10.54 MPa,体积密度为1.908 g/cm³,吸水率为3.5%。     

红柱石基刚玉-莫来石复相陶瓷的显微结构及性能

以红柱石颗粒为主要骨料,辅以莫来石颗粒和刚玉颗粒,硅微粉、铝微粉为基质料,经混合、困料及成型后,经不同温度下烧成4h,制得莫来石基刚玉-莫来石复相陶瓷,分析了烧成温度对复相陶瓷的物相组成、显微结构、烧成性能、力学性能及热学性能。结果表明:红柱石在高温下转化成针状和柱状莫来石改善复相陶瓷的烧成性能和抗热震性能;在1480℃烧成时,红柱石刚玉-莫来石复相陶瓷具有优越性能,其抗折强度为15.4MPa,耐压强度为91.6MPa,热膨胀系数为5.5×10-6/K,1100℃下水冷的抗热震次数达到99次。     

Recycling of extracted titanium slag and gold tailings for preparation of self-glazed ceramic foams

Self-glazed ceramic foams were successfully synthesized via powder sintering method, using extracted titanium slag (ETS) and gold tailings (GT) as raw materials without adding any sintering aids and foaming agents. Influence of ETS addition and sintering temperature on crystal phase evolution, physical–mechanical properties, and micro-morphology of ceramic foams was systematically studied. Results indicated that products sintered at 1180 °C with 30 wt% ETS and 70 wt% GT showed the best performance, i.e., bulk density of 1.66 g cm^?3, flexural strength of 20.4 MPa, water absorption of 0.14%, open porosity of 0.23%, and glaze Vickers hardness of 6.5 GPa. Moreover, it was observed that there existed strong correlation between bulk density and bending strength. Self-glazed ceramic foams developed in this study are expected to be used as building envelope materials and provide new ideas for effective reuse of other similar solid wastes.     

Dense and strong calcite ceramics prepared by room-temperature cold sintering based on high-pressure-enhanced solubility

Dense and strong calcite (CaCO₃) ceramics were prepared by room-temperature cold sintering with the aid of water and high pressure of up to 900 MPa. Under atmospheric pressure, calcite is barely soluble in water. However, the microstructure evolution and stress-strain analysis during cold sintering revealed that the dissolution-precipitation, plastic deformation, and pressure-solution-creep mechanisms played a crucial role in the densification and mechanical robustness of calcite ceramics, which was attributed to the significantly enhanced solubility of calcite in water under high pressure. The calcite ceramic cold sintered under 900 MPa from micron powder exhibited the highest relative density of 92.1% and best mechanical properties with compressive strength, flexural strength, hardness, and Young's modulus of 276.5 MPa, 52.5 MPa, 1.64 GPa, and 53.7 GPa, respectively. The as-prepared calcite ceramic was stronger and harder than most stones and cement, indicating its promising application as novel building and biomimetic materials. The present study also provides a new strategy for densifying ceramics with low solubility by cold sintering.     

新型耐水石膏基墙体材料制备及性能研究

就石膏墙体材料的轻质化目的,运用两种不同的EPS颗粒的加入工艺,对两种工艺的耐水石膏材料的吸水率、强度等多种系数及性能开展对比研究,最终经过试验验证可知,EPS掺入最优值是1.3%,基于此石膏表观密度是839.06 kg/m~3。干燥时的抗压及抗折度是4.05和2.06 MPa,两者软化系数是0.517和0.650,对比未加EPS颗粒时提升百分比分别为20.8%和11.5%。虽然掺入ESP颗粒后要比未掺入的强度要大,但石膏耐水性获得了显著的提高,并且符合《石膏砌块》以及《建筑隔墙用轻质板条》对于石膏材料的性能要求。     

亚微米氧化铝粉体在建筑陶瓷板材中的应用研究

采用建筑陶瓷板的制备工艺,将亚微米氧化铝粉体加入到陶瓷板材坯料中,研究了其对陶瓷板材外观、烧结性能和力学性能的影响。结果表明:在常规的生产条件下,亚微米氧化铝粉体主要以α-Al₂O₃颗粒的形式均匀分布在坯体中,具有较强的增白效果。当氧化铝粉体加入量在15%(质量分数)以内时,陶瓷板材样品的吸水率低于0.1%,烧结致密化程度较高,抗弯强度随加入量增加而提高。当加入量继续增加,吸水率增大,抗弯强度下降。氧化铝粉体加入量为15%(质量分数)时,样品的抗弯强度达到最高值96 MPa,比未外加氧化铝的样品提高了30%。在白度较低的低品质原料中,通过加入亚微米氧化铝粉体可大幅度提高产品的白度和强度,既可减少优质资源的消耗,又能较好地满足陶瓷板材对装饰效果和力学性能的要求。     

油井土、废玻璃基多孔陶瓷的制备及结构表征

利用油井土、废玻璃作为主要原料,同时以碳酸钙作为造孔剂,通过控制烧结过程,最终制备多孔陶瓷材料,并利用XRD、SEM等对样品进行结构表征。本研究的目的是为了研究油井土、废玻璃、碳酸钙的比例以及烧结温度对孔隙率、机械强度、体积密度、吸水率、微观结构和结晶程度的影响。结果表明样品A3呈现大孔均匀的微观结构,是通过添加35wt％油井土、40wt％废玻璃、20wt％碳酸钙、5wt％硅酸钠在较低的烧结温度下来获得,其孔隙率、抗压强度、抗弯强度、体积密度和吸水率的值分别为52．38％、4．43 MPa、12．59 MPa、1．07 g／cm3和29．56％。并观察到其机械强度、吸水率和微观结构（孔径及孔径分布）有良好的相关性。     

Synthesis and characterization of porous ceramics from spodumene tailings and waste glass wool

Glass wool waste remains a challenging waste fraction with relatively little utilization prospects. The present study investigated the development of porous ceramic materials from glass wool waste and spodumene tailings mainly made of quartz feldspar sand (QFS), with 0.05–0.5% silica carbide (SiC) as a pore-forming agent. The formulated compositions were sintered at 950 °C and analyzed in terms of mechanical properties, phase composition, and microstructure using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray micro-computed tomography. The results showed that a synergetic effect of glass wool and SiC started to be significant from 15 wt% glass wool and 0.05 wt% SiC, the strength reducing and the porosity increasing with the increase of SiC. The porous ceramics were largely amorphous, with compressive strength ranging from 5 to 30 MPa while the water absorption and apparent density ranged from 2 to 10% and 0.7–1.2 g/cm³, respectively. The total porosity varied between 20 and 75%, and the wall thickness between 62 and 68 μm; besides, most of the prepared materials floated in water. These results are of interest for the repurposing of glass wool waste in the development of non-flammable lightweight materials for potential filtering or high-rise building applications.     

Optimal Composition of Zircon–Fused Silica Ceramic Cores for Casting Superalloys

The dependence of flexural strength on crystalline phase content, residual porosity, and sintering temperature has been investigated for ceramic cores based on a mixture of fused silica and zircon. The rule of binary particle mixture, adopted for three particle sizes of fused silica, predicts a critical weight fraction of fine (zircon) particles of 46.9 wt% for the best packing. However, the optimal composition of a 37.8 wt% zircon–fused silica mixture for the flexural strength of ceramic cores found experimentally is lower in zircon content. The content of α-cristobalite +α-quartz crystallized from infilling silica sols exceeds ∼3 wt% when the strength decreases from ∼10 MPa to ∼6 MPa in samples sintered at 899–927°C. The degradation is ascribed to microcracking and the loss of coherency between the fused silica grains and the infilled silica due to β- →α-phase transformation on cooling and differential densification during sintering.     

水泥添加量对电解锰渣免烧砖性能的影响

控制骨料掺入量为20％,成型压力为2 MPa,混料含水率为25％的条件下,系统研究了水泥添加量对电解锰渣免烧砖性能的影响.结果表明:当水泥添加量为20％时,电解锰渣免烧砖7 d抗压、抗折强度分别为10.21 MPa和2.35 MPa,28 d抗压、抗折强度分别为13.76 MPa和2.74 MPa,体积密度为1.36 g/cm3,线收缩率为1.13％,吸水率为33.32％,饱和系数为1.47,有轻微泛霜现象产生,强度达到国家烧结普通砖的标准要求,其他性能满足国标一级品的要求.