烧成工艺制度对含钛高炉渣制备发泡陶瓷性能的影响

以页岩、含钛高炉渣为主要原料,碳化硅为发泡剂,在不同的烧成工艺制度下制备发泡陶瓷.实验采用XRD及SEM等测试方法,对试样进行结构表征和性能测试.结果表明,页岩含量为62wt％,含钛高炉渣为15wt％,同时添加二氧化硅粉、球粘土为辅料,在烧成温度1070℃,保温时间60 min,高温区(900℃ ～烧成温度)的升温速率3℃/min的条件下制得的发泡陶瓷体积密度为0.316 g/cm3,导热系数为0.15 W/(m·K),发泡陶瓷的主晶相为斜长石相、石英相和辉石相.     

高效隔热保温陶瓷材料的研制

以建筑抛光砖原料为基础料,添加少量的矿化剂和氧化镁,经干压成型后于1220℃-1300℃烧成下制备了具有防水、保温功能的闭孔高温发泡陶瓷.运用XRD、显微镜测试手段对发泡陶瓷的孔径分布、显微结构、物相组成进行了表征,探讨了原料配方、烧成制度对制品的主要性能,如:导热系数、吸水率、密度和强度的影响.结果表明,发泡陶瓷的气孔率高达66.72%(闭孔气孔率为66.39%,开孔气孔率为0.33%);体积密度为0.7987g/cm3,吸水率为0.41%;抗压强度为10.89MPa;导热系数为0.198W/(m·K);主晶相为石英和莫来石;且孔径和气孔率随着烧成温度升高而增大,气孔率越高,发泡陶瓷的抗压强度和导热系数越小.     

发泡剂含量和发泡温度对无碱玻璃纤维废丝制备泡沫玻璃的性能影响

以无碱玻璃纤维废丝为主要原料,SiC为发泡剂,用烧结发泡法制备了高强度低密度保温泡沫玻璃。研究了发泡剂含量及发泡温度对泡沫玻璃气孔率、孔结构、表观密度、抗压强度和导热率的影响。研究结果表明,随着发泡剂含量的增加,孔径逐渐增大,表观密度和抗压强度降低,过多的发泡剂会导致大气孔的出现;随着发泡温度的提高,泡沫玻璃的气孔逐渐增大,表观密度呈现下降趋势,当发泡温度过高会导致大孔和连通孔的出现;当发泡剂含量为3wt%,发泡温度为950℃,保温时间为30min时制得的泡沫玻璃综合性能最佳,表观密度为0.216g/cm~3,抗压强度为8MPa,抗折强度为4MPa,吸水率为0.28%,导热系数为0.061W/(m·k)。     

球土含量对环保型轻质材料性能的影响

本文以陶瓷抛光废料为主要原料,辅以球土、长石、石英等,制备一种以闭口气孔为主的新型轻质建筑材料.在此基础上,采用XRD、体式显微镜、导热仪等研究了球土含量对试样的体积密度、抗压强度、物相组成、导热系数等性能的影响.实验结果表明:随着球土含量的增多,材料中莫来石相开始形成并逐渐增多,抗压强度也逐渐增强;另一方面,随着球土添加量的增加,试样中孔径明显变小,体积密度增大,相应的导热系数随体积密度的增大而直线增大.     

用熔融法固化生活垃圾焚烧灰渣并制备泡沫玻璃

以质量分数为70%的生活垃圾焚烧灰渣为原料,通过添加少量其他玻璃成分调节组成,采用熔融法固化并粉碎得到玻璃态垃圾灰渣。然后以CaCO3为发泡剂,用烧结发泡法制备了性能良好的泡沫玻璃,研究了发泡温度和发泡剂含量对泡沫玻璃气孔结构、表观密度和抗压强度的影响。结果表明:发泡温度和发泡剂含量对该组成泡沫玻璃的气孔结构影响较大;随着温度升高,泡沫玻璃的气孔结构变得均匀,表观密度减小,但过高的温度会导致气体逸出,气孔收缩;在920℃发泡得到的泡沫玻璃具有低的表观密度(0.269g/cm3)和相对较高的抗压强度(2.60MPa);随着发泡剂含量从0.5%增加到2.5%,泡沫玻璃的孔径逐渐增大,表观密度减小,其抗压强度的变化趋势与气孔结构、表观密度是相一致的。     

硼砂对粉煤灰多孔玻璃结构及性能的影响

选用粉煤灰和碎玻璃为基础原料,以碳酸钙为发泡剂,采用粉末烧结法制备多孔玻璃.采用SEM对试样微观形貌进行表征,并对成品表观密度、抗压强度、孔隙率等性能进行测定,研究添加剂硼砂对多孔玻璃孔径及其分布、孔隙率和性能的影响.实验结果表明,硼砂的添加起到了明显的助熔作用,并稳定了多孔玻璃孔径分布,且硼砂添加量为3.5%时效果较好,孔径分布均匀,孔隙率为48%左右.     

氧化铁和发泡剂对煤矸石闭孔发泡陶瓷的性能影响

以固体废弃物煤矸石为主要原料,采用粉料坯体发泡法制备闭孔发泡陶瓷,探讨了氧化铁和发泡剂掺量对发泡陶瓷性能的影响。结果表明:氧化铁掺量对发泡陶瓷容重、抗压强度和导热系数影响较大;发泡剂掺量对发泡陶瓷孔径大小、孔的均一性具有显著影响。在外加6 wt%氧化铁的前提下,发泡剂掺量为1.8~2.0 wt%时,可烧制出容重较低,孔径大小适中,保温隔热性能较好的发泡陶瓷。最终以煤矸石掺量为60 wt%的坯料烧结出容重为170~270 kg/m3,抗压强度为1.24~3.71 MPa,导热系数为0.06~0.09 W/(m·k)的发泡陶瓷。     

低品位钾长石制备多孔保温隔热陶瓷研究

以低品位钾长石为主要原料,碳化硅为发泡剂,通过高温发泡法制备多孔保温隔热陶瓷.分别采用X-射线衍射(XRD)和超景深显微成像对保温隔热陶瓷的晶相组成和结构形貌进行表征,研究了烧结温度与保温时间对多孔保温隔热陶瓷孔结构、导热系数、抗压强度、体积密度和吸水率等性能的影响.结果表明,烧结温度为1250℃、保温时间为30 min时制备的多孔陶瓷材料性能最优,样品的导热系数为0.072 W/(m·K),抗压强度为3.429 MPa,吸水率为13.5％,体积密度为0.542 g/cm3.     

发泡法制备莫来石多孔陶瓷

以碳化硅及碳酸钙为造孔剂,采用发泡–注凝成型结合添加造孔剂法制备了具有大孔–介孔复合孔结构的莫来石多级孔陶瓷,研究了SiC加入量对莫来石多孔陶瓷常温物理性能和高温隔热性能的影响。结果表明:以莫来石粉体为主要原料,以CaCO₃和SiC为造孔剂,采用发泡结合添加造孔剂法可制备具有较高闭气孔率的莫来石多孔陶瓷;当SiC加入量为4%(质量分数)时,所制备试样的导热系数最低,其孔隙率约为69.9%。     

矾土基合成莫来石质多孔陶瓷的研制

采用发泡法与添加造孔剂相结合,以高铝矾土和高岭土为骨料,长石作熔剂,并添加适量的煤、MgSO4和CaSO4作发泡剂,煤为造孔剂,PVA为粘结剂,干压成型后于1500℃左右烧成制备了莫来石质多孔陶瓷。制得的多孔陶瓷莫来石生成量高达90%以上,其气孔分布均匀,孔径分布范围为100～300μm;气孔率高达52.3%（闭孔气孔率为38.7%,开孔气孔率为13.6%）;体积密度为0.9731g/cm3;抗压强度为25.1317MPa;导热系数为0.143W/（m.K）的多孔陶瓷。     

Utilization of gold tailings for the construction of foamed ceramics used in external insulation buildings

The utilization of gold tailings and bentonite as raw materials for prepared foamed ceramic was studied. The effects of boric acid and titanium dioxide content on the properties and microstructures of foamed ceramic were studied from the aspects of bulk density, compressive strength, bending strength, phase composition, and micromorphology. These results show that the synergistic effect of boric acid and titanium dioxide leads to the crystallization of quartz, which enhanced the compressive strength and bending strength and decreased the thermal conductivity of foamed ceramics, while the bulk density increases gradually with the addition of titanium dioxide. Taking into account all of these properties, the optimal results are as follows: bending strength of 1.111 MPa, compressive strength of 1.165 MPa, bulk density of 0.258 g/cm³, the porosity of 81.89%, the thermal conductivity of 0.088 (W/(m⋅K)). This study indicated that gold tailings are a promising candidate for the preparation of foamed ceramics used as external insulation building materials.     

Controllable preparation of porous ZrB2–SiC ceramics via using KCl space holders

In this work, a novel and facile technique based on using KCl as space holders, along with partial sintering (at 1900 °C for 30 min), was explored to prepare porous ZrB₂–SiC ceramics with controllable pore structure, tunable compressive strength and thermal conductivity. The as-prepared porous ZrB₂–SiC samples possess high porosity of 45–67%, low average pore size of 3–7 μm, high compressive strength of 32–106 MPa, and low room temperature thermal conductivity of 13–34 W m⁻¹ K⁻¹. The porosity, pore structure, compressive strength and thermal conductivity of porous ZrB₂–SiC ceramics can be tuned simply by changing KCl content and its particle size. The effect of porosity and pore structure on the thermal conductivity of as-prepared porous ZrB₂–SiC ceramics was examined and found to be consistent with the classical model for porous materials. The poring mechanism of porous ZrB₂–SiC samples via adding pore-forming agent combined with partial sintering was also preliminary illustrated.     

Preparation of high strength foam ceramics from sand shale and steel slag

Foam ceramics with high strength were successfully fabricated by using sand shale and steel slag as the major materials and SiC as foam agent. The influence of raw materials ratio and heat treatment temperatures on crystalline phases, porosity, mechanical properties and pore structures was investigated via XRF, XRD, SEM, DTA-TG, Micro-CT. The results indicate that the raw materials composed of 94 wt% sand shale and 6 wt% steel slag enable the fabrication of foam ceramics possessing strength of 29.98 MPa, bulk density of 0.821 g/cm³, total porosity of 67.22%, closed porosity of 55.27% and thermal conductivity of 0.08 W/(m·K). Micro-CT result shows that the pores with an average size of 267.05 μm are isolated. Pore wall thickness conforms to normal distribution, and it ranges from 18 to 42 μm. The superior property makes it promising high-strength and lightweight material in application fields, including thermal insulation materials and lightweight building materials.     

Preparation of foamed ceramics from steel slag with high calcium and iron content

In this paper, steel slag foamed ceramics were fabricated by using steel slag, kaolin, feldspar, and quartz as main raw materials, and adding SiC as high-temperature foaming agent. The effects of steel slag content and SiC particle size on porosity and mechanical properties of foamed ceramics were researched. Results indicate that when content of steel slag is 40 wt%, and particle size of SiC is 20 µm, foamed ceramics exhibited optimized properties: water absorption rate of 2.59%, total porosity of 55.91%, bulk density of 1.33 g·cm⁻³, and compressive strength of 1.21 MPa. The results show that with the increase of steel slag content, the phase composition of foamed ceramics changes, and foam process is hindered. The increase of steel slag content contributes to the formation of diopside. Fe³⁺, Fe²⁺ in liquid phase enter into diopside by solid solution, the amount of liquid phase decreases. Liquid phase mass transfer slows down, and content of SiC in liquid phase decreases, so that the porosity decreases. At the same steel slag content, different SiC particle size affects the difference between pressure inside the closed pore and surface pressure, thereby the porosity changes.     

泡沫掺量对发泡碱激发矿渣聚合物性能和孔隙特征的影响

以水玻璃激发矿渣为胶凝材料,采用压缩空气发泡方式制备了泡沫矿渣聚合物材料,通过Image-Pro plus(IPP)表征了不同泡沫掺量下泡沫矿渣聚合物的孔隙结构特征,并研究了泡沫掺量对泡沫矿渣矿物聚合物干密度、抗压强度和导热系数的影响.结果表明:当泡沫掺量为4.45%~10.70%(质量分数)时,随泡沫掺量增加,泡沫矿渣聚合物的孔隙率增加、平均孔径及孔圆度值增大,泡沫矿渣聚合物相应的干密度、抗压强度和导热系数均呈负指数关系降低且相关性强;当泡沫掺量为4.45%~12.00%(质量分数)时,所制备碱激发矿渣聚合物泡沫材料的干密度389~1325 kg/m3、抗压强度1.12~17.81 MPa、导热系数0.0813~0.2211 W/(m·K),其综合性能优于通用水泥泡沫混凝土制品.     

尾矿制备气泡混合轻质土的力学与抗冻性能研究

以尾矿制备气泡混合轻质土,研究了湿密度和尾矿质量掺量对轻质土力学和抗冻性能的影响,并研究了尾矿对轻质土气孔结构的影响。结果表明,气泡混合轻质土的抗压强度与湿密度成正相关,与尾矿掺量成负相关。当尾矿掺量达到45%(质量分数,下同)时,湿密度为700 kg/m³和800 kg/m³的轻质土抗压强度分别为0.97 MPa和1.40 MPa,相比未掺尾矿的轻质土强度分别下降约69%和66%。尾矿制备气泡混合轻质土具有良好的抗冻性,30次冻融循环中,湿密度为700 kg/m³尾矿掺量为0%~45%的轻质土抗压强度损失率均在15%以内,且抗压强度均大于0.80 MPa,提高湿密度等级可以进一步改善轻质土的抗冻性。尾矿的掺入会导致轻质土孔隙率和平均孔径增大,孔圆度降低,相比于未掺尾矿的轻质土,当尾矿掺量达到30%时,孔隙率增大3.58%、平均孔径增大16.7%、圆度值增加7.4%。     

利用核桃壳的形态结构优化Al2O3多孔材料的孔结构和性能

首先将质量分数为5%的ZrO₂溶胶、7%的Al₂O₃溶胶、3%的SiO₂溶胶作为浸渍试剂对核桃壳粉（WSP）浸渍处理。然后以α-Al₂O₃微粉为主原料,以处理后的WSP为造孔剂,制备了Al₂O₃多孔材料。研究了溶胶浸渍处理后WSP对多孔材料孔结构、热导率和力学性能的影响。结果表明,在Al₂O₃多孔材料的孔中可以清楚地观察到WSP的形变,这是优化陶瓷孔结构的重要因素。通过使用质量分数为3%的SiO₂溶胶浸渍处理的WSP,可以获得低热导率(200℃,0.297 W·m^-1·K^-1)和高耐压强度（43.5 MPa）的Al₂O₃多孔材料,并在孔中发现了莫来石的交叉网络结构。     

粉煤灰发泡陶瓷的制备及性能研究

面对日益匮乏的陶瓷原料,利用固体废弃物来制备发泡陶瓷已是当今趋势。以粉煤灰为主要原料,研究铬渣掺量、碎玻璃掺量和粉磨工艺对粉煤灰发泡陶瓷的影响。结果表明,掺入适量的铬渣可改善粉煤灰发泡陶瓷的性能,小掺量的碎玻璃对粉煤灰发泡陶瓷的性能影响较小。当原料配比为m(粉煤灰)∶m(铬渣)∶m(长石)∶m(碎玻璃)=60∶10∶20∶10时,采用湿法粉磨3 h,可以制得平均孔径为0.64 mm,体积密度为368.54 kg/m³,抗压强度为8.11 MPa的发泡陶瓷。     

Improved mechanical strength and thermal resistance of porous SiC ceramics with gradient pore sizes

Thermal insulation applications of porous SiC ceramics require low thermal conductivity and high mechanical strength. However, low thermal conductivity and high mechanical strength possess a trade-off relationship, because improving the mechanical strength requires decreasing the porosity, which increases the thermal conductivity. In this study, we established a new strategy for improving both the mechanical strengths and thermal resistances of porous SiC ceramics with micron-sized pores by applying a double-layer coating with successively decreasing pore sizes (submicron- and nano-sized pores). This resulted in a unique gradient pore structure. The double-layer coating increased the flexural strengths and decreased the thermal conductivities of the porous SiC ceramics by 24–70 % and 29–49 % depending on the porosity (48–62 %), improving both their mechanical strengths and thermal resistances. This strategy may be applicable to other porous ceramics for thermal insulation applications.     

Effect of Ca and Mg on the properties of foamed ceramics prepared with multisolid waste

With vanadium tailings and lead-zinc tailings as the main raw materials, gold tailings, waste glass powder, other fluxes and SiC foaming agents are added to prepare foamed ceramics. The effects of Ca and Mg in the fluxes of calcite, talc, and dolomite on the appearance, pore size, porosity, bulk density, and compressive strength of the samples were investigated and the mechanisms of the effects were analyzed. The XRD results showed that the sample consisted primarily of quartz, albite, augite, and a small amount of corundum. Calcite favors the formation of the augite phase, talc favors the formation of the albite phase, and dolomite combines the advantages of both. The formation of albite reduces the viscosity of the melt, and the formation of augite greatly enhances the strength of foamed ceramics. It has been shown that by adding 8% dolomite, a foaming ceramic with a bulk density of .561 g/cm³, a porosity of 62.77% and a compressive strength of 10.823 MPa can be prepared, resulting in a low-cost, lightweight and high strength foamed ceramic partition.