拟薄水铝石中硫酸根的存在形式及其对拟薄水铝石性质的影响

A series of pseudo-boehmite samples with their sulfate radicals（SO42-） concentration ranging from 0.9% to 3.0%were prepared by the reaction of NaAlO2 solution on Al2（SO4）3 solution. The existing form of sulfate radicals was investigated.Results have shown that sulfates in pseudo-boehmite included two parts, the soluble sulfate radicals and the insolublesulfate radicals, which accounted for 99% of the total amount of sulfate radicals. XRD, low-temperature N2-adsorption, andTEM were used to characterize the properties of these pseudo-boehmite samples. Results have shown that the relative crystallinityand crystal size of pseudo-boehmite decreased with the increase of sulfate radicals in the support. In the meanwhile,the bound water content in pseudo-boehmite increased. The TEM images of pseudo-boehmite indicated that the pseudoboehmitewas prone to become amorphous hydrated alumina. However, the effect of sulfate content on the specific surfacearea and pore structure of aluminium oxide was insignificant.     

富铝β沸石的制备和表征

采用微型晶化釜,在投料硅铝比(n(SiO_2):n(Al_2O_2),简称SAR)为3～14,含氟、低水含量以及无钠/低钠的SiO_2-Al_2O_3-四乙基氟化铵-H2O体系中、近中性和晶化温度170℃条件下,考察了富铝β沸石的晶相生长规律。采用XRD,SEM,~(27)Al MAS NMR,XRF,BET等方法,分析了铝源、晶化时间、系统水含量(n(H_2O):n(Si+Al))、投料SAR、原料焙烧温度等因素对晶化过程的影响。实验结果表明,以焙烧后的无钠/低钠硅铝胶为铝源有利于抑制杂相生成,适宜的n(H_2O):n(Si+Al)为3.5左右,晶化时间为7 d以上;投料SAR在10以下时,随焙烧温度的升高,晶化活性提高,经过1 000℃以上高温焙烧,投料SAR最低为7时能达到较高晶化活性;投料SAR在10以上时,随焙烧温度的升高,晶化活性降低,当投料SAR为10～14、焙烧温度为600℃时,可获得纯相、高结晶度和SAR为15以下的富铝β沸石;沸石产品形貌多为团聚体,多数试样可辨初级晶粒大小多为微米级(0.5～2.0μm),个别试样多为纳米级(30～100 nm)。     

大孔容拟薄水铝石试验研究

本文通过改变拟薄水铝石生产条件和添加助剂的方法，研究探讨了对拟薄水铝石孔容影响的条件。     

Z/M对RFCC催化剂反应性能的影响

以稀土超稳Y型分子筛和拟薄水铝石为主要原料制备了重油催化裂化(RFCC)模型催化剂,通过N 2物理吸附和高级裂化评价装置研究了水热减活RFCC模型催化剂中Y型分子筛与基质比表面积之比(Z/M)及其对催化裂化反应性能的影响。结果表明,拟薄水铝石含量越高,Y型分子筛抵御高温水热破坏的能力越差,Z/M越小。拟薄水铝石质量分数为30%时,水热减活后分子筛比表面积仅为减活前的28.3%,Z/M仅为0.8。拟薄水铝石含量不仅影响催化剂的水热稳定性,还影响催化剂的形貌。拟薄水铝石含量越高,催化剂微球形貌规整性越差,当其质量分数为30%时,催化剂微球表面不仅产生了大量的孔洞,还出现了许多裂纹。随着模型催化剂Z/M下降,目标产物液化石油气和汽油产率之和逐渐降低,轻循环油产率升高,焦炭选择性变差。     

Preparation of Pseudo-boehmite and γ-Al2O3 Support by Neutralization of NaAlO2 Solution with CO2

Pseudo-boehmite (PB) and γ-Al2O3 support are prepared by neutralization of NaAlO2 solution with CO2 (mixed gases) on bench scale. PB, typically loosely packed, fibrous particle/aggregate, is obtained by adjusting concentration and flow rate of CO2 and concentration of NaAlO2 solution at a pH level lower than that commonly assumed during neutralization. After calcination at different temperatures, γ-Al2O3 supports with different pore volume and different pore size are prepared at different conditions.     

YAG：Ce Phosphors for WLED via Nano-Pesudoboehmite Sol-Gel Route

The sub-micron sized YAG ： Ce phosphors were synthesized via a modified sol-gel method by peptizing nano-pesudoboehmite particulate. It is found that YAG phase from the dried gel powders appears at 1000 ℃ then the pure YAG phase exists at a relatively lower sintering temperature of 1400 ℃. The smaller sizes of phosphors in the ranges of 1 - 3 μm are obtained due to the contribution of seeding effects of nano-sized alumina particles to strengthen each step of the processes. Both the excitation and emission spectra of photoluminescence of the phosphor obtained at 1400 ℃ meet well with the spectroscopic requirements of the WLED phosphors.     

NaAlO_2-Al_2(SO_4)_3法制备拟薄水铝石成胶机理的研究

研究了拟薄水铝石和三水氧化铝的生成机理。考察了成胶pH、成胶温度对生成物类型的影响,在此基础上确定了NaAlO2溶液和Al2(SO4)3溶液成胶过程中完全中和时的临界体积比Ψ/Ψ0,在成胶过程中,当Ψ/Ψ0≤1时,NaAlO2溶液与Al2(SO4)3溶液发生中和反应生成拟薄水铝石和/或碱式硫酸铝;当Ψ/Ψ0>1时,过量的NaAlO2溶液发生自发水解反应,生成三水氧化铝。     

低堆密度大孔体积γ-Al_2O_3的制备与表征

以Al2(SO4)3和NH3.H2O为原料合成了拟薄水铝石,经煅烧得到γ-Al2O3;采用X射线衍射、透射电子显微镜、热重-示差扫描量热和压汞法等方法对拟薄水铝石和γ-Al2O3进行了表征。表征结果显示,低堆密度大孔体积的γ-Al2O3的较佳制备条件为:反应液的pH为8、Al3+浓度为0.9mol/L、反应时间60min、反应温度70℃、NH3.H2O的质量分数为21%、800℃下煅烧5h。在此条件下制备的γ-Al2O3的比表面积为207.43m2/g、总孔体积为2.93mL/g、堆密度为0.23g/mL,且具有双孔分布,其中孔径大于100nm的孔的体积占总孔体积的58.91%,适用于大分子脱氢催化剂的载体。     

Effect of Carrier Processing Temperature on Its Properties for Adsorption of Active Metals

The influence of the carrier pseudo-boehmite (PB), which was impregnated with a Ni-Mo-P solution under over-saturation conditions and treated at different temperatures, on its property for adsorption of active metals (Ni, Mo) was studied. The results showed that the amount for adsorption of active metal was decreased with an increasing treatment temperature of the carrier. After phase transition of the carrier PB to γ-Al2O3, its capacity for adsorption of active metals was significantly reduced. The difference in properties for adsorption of active metals (Ni, Mo) by PB dried at 120 ℃ and γ-Al2O3 calcined at 600 ℃ was studied in detail. The results suggested that the ability of the PB carrier to adsorb metals was higher than that of the γ-Al2O3 carrier. Especially, the ratio of chemically adsorbed metals on the PB support was much higher than γ-alumina. The chemical adsorption sites on the PB carrier were proved to be much more than those on the γ-Al2O3 carrier. Ni and Mo chemical adsorption sites differed a lot on the carrier possibly because of the difference in chemical adsorption sites.