Influence of Pore-expansion Agent on the Structure and Performance of Activated Alumina Synthesized from Waste Aluminum Sludge

1 INTRODUCTION The reactivity of activated alumina adsorbent is closely related to its specific surface area: the larger the specific surface area, the better its activity and adsorbent capability are. However, in reality, the prac- tically available specific surface area or effective spe- cific area has relationship with its pore structure[1]. Since many reactant molecules are difficult to enter the pores to react with whose radius is shorter than certain critical value, the increase of p…     

Structural Characterization and Property Study on the Activated Alumina-activated Carbon Composite Material

AlCl3,NH3·H2O,HNO3 and activated carbon were used as raw materials to prepare one new type of activated alumina-activated carbon composite material.The influence of heat treatment conditions on the structure and property of this material was discussed;The microstructures of the composite material were characterized by XRD,SEM,BET techniques;and its formaldehyde adsorption characteristic was also tested.The results showed that the optimal heat treatment temperature of the activated alumina-activated carbon composite material was 450 ℃,iodine adsorption value was 441.40 mg/g,compressive strength was 44 N,specific surface area was 360.07 m2/g,average pore size was 2.91 nm,and pore volume was 0.26 m3/g.According to the BET pore size distribution diagram,the composite material has dual-pore size distribution structure,the micro-pore distributes in the range of 0.6-1.7 nm,and the meso-pore in the range of 3.0-8.0 nm.The formaldehyde adsorption effect of the activated alumina-activated carbon composite material was excellent,much better than that of the pure activated carbon or activated alumina,and its saturated adsorption capacity was 284.19 mg/g.     

Influence of Impurity Na2O on Crystalline Structure of Cordierite Synthesized from Aluminum Sludge

Waste aluminum sludge, talc powder and clay were used to synthesize cordierite in this research. The impurities, such as Fe2O3, CaO, K2O and Na2O, in the raw materials have some influence on the structures and properties of the materials. In this paper, we mainly discuss the impact of impurity Na2O on the structure of cordierite, based on which the permitted amount of Na2O was determined. The results show that Na2O with the amount less than 0.6% has little influence on the cordierite formation; while when its amount increasing from 0.6% to 0.7%, the content of cordierite decreases from 86% to 84% and the permitted amount for Na2O in the raw materials is less than 6% with the best amount less than 0.3%. X‘pert plus software analysis results show the impurity Na2O has no influence on the cordierite space group and only the lattice parameters vary slightly; but it has much influence on the structure of Mg-AI spinel and the lattice parameters are much changed.     

Point Defect Phenomena of Crystalline Structure in Some Common Structural Materials

1 INTRODUCTION That crystal is the internal particles arranged re- peatedly and periodically in three-dimensional space or the solid with space lattice structure is the com- plete definition of crystal at absolute zero tempe- rature[1, 2]. But actual crystals deviate from the ideal ones in certain degree because of various influences, such as the impurity and thermal vibration of crystal particles, which is called crystal structural defect. Strictly speaking, all factors causing the crysta…     

保温时间对铝厂废渣研制的氧化铝磨介微观结构及性能影响

以铝型材厂废渣为主要原料,通过添加少量粘土,滑石及碳酸钡复合助烧剂研制刚玉耐磨瓷球.探讨不同保温时间对瓷球微观结构及各项性能指标的影响.采用XRD和SEM等测试手段探讨其晶相结构和显微结构并测试抗弯强度、硬度、磨损率和气孔率等性能指标.结果表明:最佳保温时间为3 h,此时样品由4种晶相组成,其中刚玉为主晶相,含量约75%,其各项性能分别为:吸水率为0.032%,气孔率为0.105%,体积密度为3.289 g/cm3,抗弯强度为136 MPa,显微硬度为8.25 GPa,磨损率为0.044 1%/h.     

铝厂污泥在不同煅烧温度的晶相结构研究

铝厂污泥主要成分是-AlOOH,其中部分是晶体,部分是无定形体。将此污泥分别于450,600,800,1000,1050,1200和1300 ℃进行了煅烧,探讨污泥在不同温度下的晶相变化,为污泥的综合利用提供可靠的数据。采用XRD法和SEM法表征了污泥在不同温度下的晶相结构和显微结构。实验结果表明:随着煅烧温度的提高,污泥发生如下变化过程: 这与常规转化规律不同。在450,600,800,1000和1100 ℃的试样中均形成了-Al2O3和无定形体结构的微晶,随着温度的升高,-Al2O3含量增加而无定形体结构的微晶含量降低。当煅烧温度上升至1200和1300 ℃时, - Al2O3和无定形体结构的微晶全部转变为 - Al2O3。 -Al2O3是介稳态,高活性,-Al2O3是稳定态,低能态。     

Influence of TiO_2 Mineralizer on the Crystalline Structure of Cordierite Synthesized from Aluminum Slag

By adding small amount of TiO2, aluminum slag could be used to synthesize cor-dierite, α-Al2O3, TiO2 and dehydrated talc could generate solid solution to accelerate the solid-state reaction to form cordierite. The experimental results show that the content of cordierite increases with the increase of TiO2 added. 3.0% of TiO2 is determined to be the best amount, because all crystalline substances are converted into cordierite at this content. Philips X‘pert plus software analysis shows that when the content of TiO2 is from 0 to 1.0%, cordierite has the same hexagonal structure as the single crystal and the lattice parameters change slightly; when the content of TiO2 is from 1.0 to 2.0%, the cordierite still keeps hexagonal structure but the lattice parameters change greatly; when the content of TiO2 is from 2.0 to 3.5%, the cordierite is converted from hexagonal into rhombic and the lattice parameters change accordingly.     

利用硅灰粉尘研制多孔陶瓷

以硅灰粉尘为主要原料制备高比表面多孔陶瓷.主要探讨粘土结合剂及不同烧结温度对该多孔陶瓷的孔结构及气孔率、体积密度等性能指标的影响,采用SEM、BET等分析测试手段表征各试样的微观结构.结果表明,硅灰粉粒子超细、比表面积大、成本低廉,是制造大比表面多孔陶瓷的理想原料.粘结剂的加入会降低样品的气孔率,确定5%(质量分数)的粘土为最佳,烧结温度选择为750℃,此时多孔陶瓷的气孔率为41.91%,强度为23.61 MPa,比表面积达到24.22m2·g-1.     

硅藻土/牡蛎壳制备可回收废水除磷材料的研究

用牡蛎壳和硅藻土为主要原料经成型烧结制备可用于废水除磷的型体材料.探讨烧成温度,硅藻土添加量对牡蛎壳试样成型性能及其除磷效果的影响.采用磷钼蓝分光光度计法测试各样品的除磷效果,用XRD法表征样品的晶相组成,用SEM观察样品的微观结构,EDS测定元素组成.实验结果表明,牡蛎壳除磷材料只有在低温下烧结才有一定的强度,烧成温度高于700℃材料易粉化.650℃为最佳烧成温度,硅藻土10%+牡蛎壳90%为最佳配方,除磷时间为12 d时,除磷效率达到93.86%.     

Influence of Cr2O3 on the Structure and Property of Mg-Al Spinel Synthesized by Waste Slag in Aluminum Factory

Via the solid phase reaction, Mg-Al spinel has been synthesized by using industrial waste slag from aluminum factory, basic magnesium carbonate and a little amount of clay as the main raw materials. The influences of Cr2O3 mineralizer on crystalline structure, micro-morphology and properties of synthesized Mg-Al spinel are discussed. The synthesized product was characterized by using XRD and SEM, and the relative contents of each crystalline phase are calculated by relevant analytical software such as Philips plus, Rietveld quantification and so on. The experimental results show that a certain amount of Cr2O3 is helpful to the formation of Mg-Al spinel, and when the addition of Cr2O3 is 2.0%, Mg-Al spinel in the system exists in the form of solid solution (Mg0.68Al0.32)(Al0.84Mg0.16)2O4 whose content is the highest reaching 91%. Then the corresponding indexes of each property are as follows: water absorption 3.0%, apparent porosity 9.8%, bulk density 3.36 g·cm-3, and flexural strength 83.32 MPa. Therefore, we can confirm that the optimum addition of Cr2O3 mineralizer is 2.0%.