IDR双汽提尿素装置现状及控制设想

本文对IDR尿素装置的目前生产情况进行了统计和分析。同时根据观察、统计和测试,对某些问题提出思路。     

低含量Pr3+掺杂WO3的制备及其光催化分解水析氧活性

采用低温固相反应法制备低含量Pr^3＋（0.05%,质量分数）掺杂的WO3催化材料,采用XRD、XPS和DRS对样品进行表征和分析,考察催化剂在电子接受体Fe3＋溶液体系下的光催化分解水制氧活性。结果表明,0.05%Pr^3＋掺杂可以使WO3样品的光谱响应范围向可见光区拓展。XPS分析表明,Pr^3＋掺杂可以导致催化剂样品表面氧缺位增加。在可见光辐射下光催化分解水制氧的实验中,0.05% Pr^3＋掺杂WO3样品的光催化析氧速率高达196.64μmol/（L.h）,是未掺杂WO3的2倍。     

伊利石在铝酸钠溶液中的反应脱硅过程研究

为了更清楚地了解伊利石在拜耳法溶出过程中的反应行为，本文对伊利石在合成铝酸钠溶液中的溶出动力学进行了研究，测得其活化能为114，73kJ/mol。并研究了溶液苛性碱浓度对伊利石的反应速率的影响；添加石灰可以有效的增加伊利石的反应率，提高脱硅效率。为拜耳法生产氧化铝的脱硅过程及防止结疤提供理论依据。     

铝酸钠(钾)溶液种分过程的分解率和粒度分布

采用等温间歇式反应器研究了纯铝酸钠和铝酸钾溶液在种分过程的分解率、粒度分布(PSD)的变化规律,同时对分解产品进行了XRD、SEM和TG/DTG分析.结果表明,在相同的分解条件下,铝酸钾溶液的分解率大于铝酸钠溶液;铝酸钠和铝酸钾溶液中颗粒的粒度分布随时间变化具有显著差异;产品的XRD显示,分解过程中铝酸钾比铝酸钠溶液中的晶体结晶度完整,但产品的TG/DTG曲线却没有明显的差别.对于不同ακ值的铝酸钠和铝酸钾溶液,这些差异是相似的.铝酸钾与铝酸钠溶液在种分过程中的成核速率不同可能是引起分解率和粒度分布产生差异的原因.     

氢氧化铝晶粒的应力与强度分析

根据国内氧化铝工业生产现状，结合氢氧化铝晶粒的显微结构，利用有限元方法，对氢氧化铝晶粒进行了结构静力分析，得到了氢氧化铝晶粒中填充小晶体的填充位置、数目及晶粒破损的缺口尺寸与晶粒强度的关系，并对实际产品的显微结构与强度的关系进行了考察. 结果表明，晶粒中存在小晶体填充且填充位置处于整个缺口尺度的75%时，强度改善最为明显，并且强度随填充小晶体数目的增多而提高；晶粒的缺口尺寸在1~2 mm范围内变化时，缺口越小，强度越好；通过氢氧化铝产品中晶粒的显微结构，应用有限元分析，可以从理论上判断氢氧化铝产品的强度.     

Dissolution mechanism and solubility of hemimorphite in NH3-(NH4)2SO4-H2O system at 298.15 K简

The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） analysis. The results show that hemimorphite is soluble in NH3-（NH4）2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-（NH4）2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr（NH3） （total ammonia concentration） at different NH3/NH4^＋ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct（NH3）-4.1245 mol/kg NH3-（NH4）2SO4-H2O solution to 0.0046 mol/kg in cT（NH3）=7.6035 mol/kg NH3-（NH4）2SO4-H2O solution.     

Synthesis and characterization of triclinic structural LiVPO4F as possible 4.2 V cathode materials for lithium ion batteries

A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction （CTR） process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted under an Ar atmosphere to yield VPO4. The transition-metal reduction is facilitated by the CTR based on C→CO transition. These CTR conditions favor stabilization of the vanadium as V^3＋ as well as leaving residual carbon, which is useful in the subsequent electrode processing. Secondly, VPO4 reacts with ElF to yield LiVPO4F product. The property of the LiVPO4F was investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement. XRD studies show that LiVPO4F synthesized has triclinic structure（space group p I ）, isostructural with the naturally occurring mineral tavorite, EiFePO4-OH. SEM image exhibits that the particle size is about 2μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of LiVPO4F powder is 119 mA·h/g at the rate of 0.2C with an average discharge voltage of 4.2V （vs Ei/Li^＋）, and the capacity retains 89 mA·h/g after 30 cycles.     

几种铝化合物的热力学性质

结合作者的量热测定结果和前人的工作，研究了氧化铝工业中最常见的几种铝化合物如α－Ａｌ２Ｏ３，γ－Ａｌ２Ｏ３，三水铝石一水软铝石和一水硬铝石的基本热力学性质：标准生成焓、标准熵、标准生成Ｇｉｂｂｓ自由能和热容，得到了可靠，自洽的结果。     

ZrO2固体电解质用于铝电解的初步研究

本文对YSZ型析氧阳极应用于铝电解进行了初步研究,讨论了导电引出方式,密封性以及均匀电场对电解体系的影响,并且对YSZ型析氧阳极的可行性进行了验证。结果表明:YSZ型析氧阳极用于铝电解是可行的;使用镍铬丝和纳米级La0.7Sr0.3MnO3粉末的导电引出方式是合理的;密封性以及均匀电场对电解体系的稳定性十分重要。     

Effect of 20kHz ultrasound on alumina hydrate precipitation from seeded sodium aluminate solution

1　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｔｈｅａｌｕｍｉｎａｉｎｄｕｓｔｒｙ,ｐｒｅｃｉｐｉｔａｔｉｏｎｏｆａｌｕｍｉｎａｈｙｄｒａｔｅｉｎｔｈｅＢａｙｅｒｐｒｏｃｅｓｓｉｓａｖｅｒｙｉｍｐｏｒｔａｎｔｏｐｅｒａ ｔｉｏｎ .Ｉｎｎｕｍｅｒｏｕｓｉｎｓｔａｎｃｅｓｗｈ