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 Na_2O 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…     

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.     

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%.     

反应温度与时间对铝型材厂工业污泥合成堇青石材料的得率与晶相结构影响

本研究主要探讨反应温度和反应时间对铝型材厂工业污泥合成堇青石材料的得率和晶相结构的影响。该污泥系由铝型材表面处理时产生的大量废液, 经沉淀过滤所得。主要成分是一种超细的γ-AlOOH, 其中部分是晶体, 部分是无定形体, 活性很高, 有利于堇青石晶相的形成, 能降低反应温度。 实验结果表明: 堇青石含量随着反应温度升高而增加; 晶相结构和晶胞参数与反应温度有关; 确定1350℃为最佳的反应温度; 反应时间在 2~5 h的试样中,堇青石含量增加, 在5~6 h含量降低. 5 h为最佳的反应时间。     

利用含铝废渣合成的堇青石结构表征

采用铝型材厂工业废渣,滑石粉和粘土为主要原料合成堇青石材料,用XRD和SEM法表征各样品的晶相结构和显微结构;用Rietveld Quantification内标半定量法确定各晶相的含量;用Philips X'pert plus软件确定各晶相的晶胞参数。实验结果表明:除晶胞参数发生微小变化外,合成的堇青石结构与单晶相同,属六方晶系,p6/mcc空间群;除堇青石相外,体系内还出现莫来石固溶体相和镁铝尖晶石相,他们的含量和晶胞参数也相应的进行了表征。     

陶瓷辊棒在辊道窑使用过程中晶相结构与性能变化

采用XRD和SEM方法表征不同位置辊棒的晶相结构与显微结构来探讨陶瓷辊棒在实际窑炉使用过程晶相结构和性能变化。采用物理方法表征辊棒的性能。实验结果表明:不同位置辊棒存在莫来石、刚玉、硅酸钙镁三种晶相。莫来石含量是按未使用的(80.8%)→预热带的(78.4%)→烧结带的(73.4%)→冷却带的(71.5%)的顺序降低;刚玉含量按17.7%→19.2%→18%→22.5%的顺序变化;而晶相硅酸钙镁含量按1.5%→2.4%→7.6%→6%的顺序变化;体积密度和使用寿命按上述顺序降低的,而气孔率和吸水率按上述顺序增加的。