常压富氧浸出含锗氧化锌烟尘EI北大核心CSCD

为提高含锗氧化锌烟尘中锗的浸出率,提出采用富氧常压浸出−中和工艺处理含锗氧化锌烟尘,通过调节合适的酸度控制烟尘中硅的浸出及氧的溶解,避免形成铁硅锗胶体造成锗的损失的同时控制溶液中Fe^(3+)浓度便于烟尘中硫化物的溶出。结果表明:常压富氧条件下,在温度为90℃、液固比为7 mL/g、控制终点pH为0.3~0.7的条件下浸出4 h,锗浸出率为83%,较传统工艺条件下的锗浸出率提高13%。浸出渣的物相主要为硫酸铅和硫化锌以及二氧化硅,表面出现多孔、蓬松状结构。锗主要以硅酸盐态赋存,84.94%以该状态赋存的锗被浸出,占总锗的59.24%。浸出液中Fe^(3+)浓度约为0.4 g/L,硅含量约为64.5 mg/L,实现了对Fe^(3+)及Si的控制。采用含锗氧化锌烟尘对溶液进行中和还原,表明控制溶液温度为90℃,pH为3.0,反应1.5 h,可将溶液中Fe^(3+)浓度控制在0.025 g/L内,满足后续的沉锗要求。     

锌粉置换镓锗渣草酸浸出过程

考察锌粉置换镓锗渣草酸浸出过程中,草酸浓度、浸出时间、液固比、浸出温度、双氧水浓度对镓、锗、锌、铁、铜、硅浸出率及浸出料浆过滤性能的影响,揭示在草酸浸出体系下添加双氧水促进镓、锗浸出的作用机理。结果表明,采用草酸和双氧水为浸出剂,不仅可实现镓、锗的选择性浸出,还可显著改善浸出料浆的过滤性能。双氧水促进镓、锗浸出的机理为其作为氧化剂使镓、锗单质及其硫化物氧化为可溶的氧化物;草酸与镓、锗可生成稳定络合物,而与硅的作用较弱,从而促进镓、锗的浸出,同时使浸出渣的过滤性能得以改善。在草酸浓度为110 g/L、双氧水浓度为0.12 mol/L、液固比(L/S)为8、搅拌速度为300 r/min、浸出温度为40℃、浸出时间为30 min的条件下,镓和锗浸出率分别为99.32%、98.86%,而铜、锌、硅的浸出率分别在0.82%、0.84%、0.43%,且浸出料浆的过滤速度由常压硫酸浸出体系下的0.48 mL/min提高到100 mL/min。     

锌粉置换镓锗渣硫酸浸出过程

考察锌粉置换镓锗渣硫酸浸出中,硫酸浓度、温度、液固比、浸出时间和添加剂对Ga、Ge浸出率及浸出渣过滤性能的影响,揭示添加硝酸钠和十二烷基磺酸钠促进浸出过程的作用机理。结果表明:浸出液中添加适量硝酸钠或十二烷基磺酸钠,均可促进Ga、Ge浸出;此外,十二烷基磺酸钠还可改善浸出渣的过滤性能。添加剂的作用机理为硝酸根能使Ga、Ge单质及其硫化物氧化,从而促进Ga、Ge浸出;十二烷基磺酸钠则通过促进溶液中硅胶的絮凝,减少其对Ga、Ge的吸附,同时,使浸出渣的过滤性能得以改善。在温度为90℃、液固比为10 m L/g、搅拌速度为300 r/min、浸出时间为4 h、硫酸浓度为156 g/L、硝酸钠浓度为52.29 g/L、十二烷基磺酸钠浓度为20.5 g/L的条件下,Ga和Ge的浸出率可分别达到97.01%和90.45%,浸出料浆过滤速度由未添加十二烷基磺酸钠时的0.48 m L/min提高到30.65 m L/min。     

氯盐浸出硫化银之研究

用电位—log[Cl~-]图分析高铁氯盐体系浸出硫化银的热力学可能性。用试剂硫化银进行的动力学实验考察了粒度、浸出剂初始pH值、氯离子浓度、高铁离子浓度和温度等对银浸出率的影响。结果表明,浸出过程很好地符合“未反应芯”动力学模型,求得的表观活化能为56.24千焦/摩尔,得到动力学方程式为:1-2/3R-(1-R)2/3=1.02×10_(-4)r_0~(-2)[H~+]~(0.36)[Cl~-]~3[Fe(Ⅲ)]exp(-56240/RT)t,过程受固膜扩散控制。     

含锗锌浸出渣强化解离及有价金属浸出行为

针对含锗锌浸出渣处理过程中存在有价金属回收率低、工艺复杂等问题,本文提出了Ⅰ段控铁低酸加压浸出-Ⅱ段深度高酸加压浸出的两段逆流加压酸浸工艺。深入研究了Ⅱ段深度高酸加压浸出过程中载锌、锗复杂物相解离机理以及锌、锗、铁等有价金属的深度浸出行为。结果表明：升高反应温度、延长反应时间、增加氧分压不仅能促进载锌、锗铁酸盐(MeFe₂O₄, Me=Zn, Ge)复杂物相的高效解离,也有利于Fe(Ⅲ)水解沉淀反应的发生,浸出渣物相组成由以铁酸盐为主逐步演变为以铁矾为主;酸度是影响铁酸盐热力学优势区的重要因素,其热力学稳定性随体系酸度的升高而逐渐降低,酸度过高时铁的溶解速率大于其沉淀速率,同时因H+活性增强抑制了Fe(Ⅲ)水解生成黄钾铁矾反应的发生。在反应温度150℃、初始酸度100 g/L、反应时间180 min、氧分压0.4 MPa、搅拌转速500 r/min的优化技术条件下,锌、锗的浸出率分别为92.47%、61.33%,获得的浸出终渣中主要物相为铁矾、硫酸钙,其含锌、锗、铅、银、硫分别为1.41%、370.00 g/t、3.52%、150 g/t、1...     

锌粉置换镓锗渣高压酸浸的浸出机理

研究锌粉置换镓锗渣的高压酸浸过程,考察硫酸浓度、液固比、浸出时间、浸出温度、助浸剂种类和添加量对Ga、Ge浸出率以及浸出渣过滤性能的影响。结果表明:增加硫酸浓度有利于Ga、Ge的浸出,但硫酸浓度超过156 g/L后,反而不利于Ge的浸出。浸出时间和温度对Ga、Ge浸出率影响较小,但增加浸出时间或提高反应温度均有利于改善浸出渣的过滤性能。添加硝酸钠或硝酸钙均可促进Ga、Ge的浸出,且硝酸钙的添加还可改善浸出渣的过滤性能。在硫酸浓度156 g/L、助浸剂硝酸钙60 g/L、液固比8、浸出温度150℃下浸出3 h,Ga、Ge浸出率可分别达到98%和94%以上,且浸出料浆过滤速度较常压酸浸时的提高近20倍。     

从赤泥中浸出微量元素钇的工艺研究

通过对某厂拜耳法生产氧化铝副产物赤泥中钇的酸浸工艺条件及动力学研究,同时考察了赤泥粒度、浸出温度、液固比及酸浓度对微量钇浸出率的影响,建立了钇的酸浸动力学模型。试验结果表明:在赤泥颗粒大小140目、反应温度85℃、液固比4:1、酸浓度10%时,钇的浸出率可达80%以上,同时对试验数据处理分析,得出钇的浸出符合固体产物层内扩散控制模型,动力学方程为:1-(1-X_B)~(2/3)-2X_B/3=kt,活化能为16.24k J/mol。     

Na_2SO_3从硒碲富集物中浸出硒动力学(英文)

研究用Na2SO3溶液从硒碲富集物中浸出硒的动力学。该硒碲富集物的微观形貌主要为球状体和柱状体,其粒径范围为17.77～56.58μm,且其主要成分为41.73%Se和40.96%Te。研究Na2SO3浓度(126～315 g/L)、搅拌速度(100～400 r/min)、反应温度(23～95°C)、液固比(7:1～14:1)及硒碲富集物平均粒径(17.77～56.58μm)对Se浸出率的影响。结果表明:增加Na2SO3浓度、提高搅拌速度、升高反应温度和增加液固比均可以提高Se浸出率,而增大硒碲富集物的粒径会导致Se的浸出率降低;反应温度对Se浸出率影响较大,当反应温度从23°C升高至95°C时,Se浸出率从21%增至67%;该浸出过程符合Avrami模型,其模型特征参数和表观活化能分别为0.235和20.847kJ/mol。     

采用Na2SO3溶液从硒渣中选择性浸出Se及其动力学

采用SO2还原沉金后液制得硒渣,再用Na2SO3选择性浸出硒渣,使Se得到有效分离;通过研究浸出过程中Se浸出率随时间的变化,建立该反应的动力学方程,确定Na2SO3溶液浓度、液固比、搅拌速度及反应温度对Se浸出率的影响,并计算相应的表观活化能。结果表明:增加Na2SO3溶液浓度和升高反应温度可以较大幅度提高Se的浸出率,液固比和搅拌速度对浸出Se的影响较小;Na2SO3浸出Se过程为Avrami模型混合控制,其特征参数n和表观活化能E分别为0.235和20.847 kJ/mol,Se的浸出率受反应温度的影响较大。     

在H_2SO_4-Fe_2(SO_4)_3体系中载金黄铁矿浸出动力学（英文）

在H2SO4-Fe2(SO4)3体系中研究载金黄铁矿的浸出动力学,探讨反应温度、Fe3+浓度、硫酸浓度、搅拌速度等对黄铁矿浸出的影响规律。结果表明:在H2SO4-Fe2(SO4)3体系中,在30~75°C下黄铁矿浸出过程主要受化学反应控制Fe3+浓度与黄铁矿的浸出呈正相关,通过Arrhenius经验公式求得浸出表观活化能为51.39 k J/mol。EDS与XPS分析结果表明:黄铁矿氧化过程中硫的氧化经一系列中间形态,最终被氧化成硫酸根,并伴有部分元素硫生成,符合硫代硫酸根氧化路径机理。     

Mechanoluminescence in BaSi2O2N2:Eu

Mechanoluminescence (ML), a general term for the phenomenon in which light emission occurs during any mechanical action on a solid, can be divided roughly into two classes: destructive ML and non-destructive ML. For practical use in high-end applications (e.g. pressure sensors), materials with non-destructive ML properties are preferred. This paper reports on the strong non-destructive ML in BaSi₂O₂N₂:Eu. When irradiated in advance with ultraviolet or blue light, this phosphor shows intense blue-green light emission upon mechanical stimulation such as friction or pressure. The ML has an emission band peaking at 498 nm, which is ～4 nm red-shifted compared to the steady-state photoluminescence. The origin of the ML is discussed and related to the persistent luminescence of BaSi₂O₂N₂:Eu. The same traps are responsible for both phenomena. Based on the occurrence of ML in this phosphor, we were able to show that the predominant crystallographic structure of BaSi₂O₂N₂:Eu belongs to space group Cmc2₁.     

用氢-氧取代氧-乙炔作焊接切割的必要性及可行性

阐述了用氢代乙炔的必要性．通过时HGQU2000／315火焰电孤焊割机的考察和试用证实了用氢代乙炔的可行性，比较了两种气体的性质并提出了使用特性差异和注意事项．提出了进一步探索的问题。     

Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2气氛下的腐蚀

研究了600℃时Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2 3种气氛中的腐蚀行为，Fe-15Ce合金腐蚀后发生了Ce的内氧化或形成了复杂的腐蚀产物膜，而未出现Ce的选择性氧化或硫化，这主要是合金中存在着两相及Ce在Fe中极低的溶解度的结果。Fe-15Ce合金在本实验条件下的氧化-硫化腐蚀速度低于相同温度、压力下的纯硫化。     

Thermodynamic evaluation of phase equilibria in the CaCl2-MgCl2-CaF2-MgF2 system

The phase diagram of the CaCl₂-CaF₂-MgCl₂-MgF₂ reciprocal ternary system was calculated thermodynamically from available data on the common-ion binary subsystems and from available data on the CaCl₂-MgF₂ join. This join is very nearly quasibinary and divides the system into two quasiternary systems: the CaCl₂-MgF₂-CaF₂ system with a ternary eutectic calculated at 724 +-5 °C and the CaC₂-MgF₂-MgCl₂ system with a ternary eutectic calculated at 561 +-5 °C.     

Symmetry analysis of magnetic structures possible in TbNi2Si2-TbMn2Si2 solid solutions

TbNi₂Si₂-TbMn₂Si₂ solid solutions have been studied by neutron diffraction to reveal magnetic structures with wave vectors {k ₈} = μ(b ₁–b ₂) + b ₃/2 = 2π [(1–2μ)/2, (1 + 2μ)/2, 0]/a, {k ₁₃} = b ₃/2 = 2π(1/2, 1/2, 0)/a, and {k ₁₄} = 0. The method of calculation is described and the results of calculations are given for the basis functions of irreducible representations of the space group D _4h ¹⁷ (14/mmm) that are used for the most rational search for a real model of the magnetic structure of these solid solutions. The compositions of the magnetic representations for each of the above-mentioned wave vectors and the possible variants of the mutual orientation of atomic magnetic moments in the crystallographic positions in which the magnetically active atoms (Tb, Ni, Mn) are located have been determined.     

High temperature corrosion of Fe-Cr-Mn-alloys in H2-H2S and H2-H2O-H2S gas mixtures

The sulfidation of Fe-20% Cr-30% Mn, Fe-25%Cr-20%Mn and Fe-25% Cr was studied at 700°C in H₂-H₂S and the oxidation and sulfidation in H₂-H₂O-H₂S after preoxidation in H₂-H₂O. The sulfidation rate is strongly increased for the Mn-containing alloys, layers of (Mn,Cr)S and (Mn,Fe)Cr₂S₄ are formed. Also the oxidation rate is enhanced compared to Fe-25% Cr by formation of MnCr₂O₄ instead of Cr₂O₃. The sulfidation after preoxidation leads to internal and external sulfidation of the Mn-containing alloys. With increasing oxygen pressure p(O₂) = 10^?26…10^?22 atm. of the H₂-H₂O-H₂S mixtures the sulfidation is suppressed, for the higher oxygen pressure 10^?23 and 10^?22 atm. fast oxidation prevails under formation of MnCr₂O₄. Manganese cannot increase the sulfidation resistance of alloys, in spite of the stability and low degree of disorder of its sulfide, since the mixed sulfide (Mn,Cr)S is formed which has a high degree of disorder, high diffusivities and high growth rate according to the doping effect of trivalent Cr³⁺.     

ZrB2在Al2O3-ZrB2复相陶瓷中的增韧性能

常压烧结制备了Al2O3和20wt%ZrB2/Al2O3复合陶瓷,用XRD和金相显微镜、SEM分析了其相组成、微观结构、断裂形貌,并用压痕法计算了陶瓷的断裂韧性。结果表明：Al2O3陶瓷自1500℃开始其相对密度超过99%,维氏硬度达到1897HV,断裂韧性为5.2?.3MNm-3/2;20wt%ZrB2/Al2O3复合陶瓷在1450℃时相对密度超过98%,维氏硬度达到1807HV,断裂韧性为6.7?.2MNm-3/2。微观形貌观察表明,ZrB2/Al2O3复合陶瓷韧性的增加是由于弥散分布的ZrB2在Al2O3陶瓷基体中起到遏制裂纹扩展和钉扎双重作用的结果。     

Phase Equilibria in the TeO2-CdI2 System

Using differential thermal analysis, x-ray diffraction analysis and density measurements the phase diagram of the TeO₂-CdI₂ system is built. It is characterized with four non-variant equilibria: the temperatures of the eutectic, monotectic, peritectic and peritectoidal points are at 345, 565, 470 and 240 °C, respectively. As a result of the passing of peritectic and peritectoidal reactions, two intermediate compounds with composition CdI₂·3TeO₂ (A) and 2CdI₂·3TeO₂ (B) are formed, both crystallizing in monoclinic lattice system with near unit cell parameters. The intermediate compounds A and B possess narrow solid-solution regions. The B passes through polymorphous transition, which, depending on the composition, varies between 245 and 265 °C. The two intermediate compounds, together with the initial TeO₂ and CdI₂, determine the presence of 16 phase fields: 5 monophase (melt L, α-TeO₂, β-B, α-A and α-B) and 11 two-phase. These characteristics of the phase diagram of the TeO₂-CdI₂ system (two intermediate compounds with complicated compositions CdI₂·3TeO₂ and 2CdI₂·3TeO₂, two low-temperature eutectic and monotectic transitions at T_E = 345 and T_M = 570 °C, respectively, are sufficient precondition for obtaining of new oxychalcohalide glasses with wide region of glass formation in three-component systems from the Me_nCh_m-TeO₂-CdI₂ kind (Me_nCh_m—glassformer).     

Dislocations in Mo5SiB2 T2 phase

Dislocation structures in a nearly single phase annealed Mo₅SiB₂ T2 alloy have been investigated by transmission electron microscopy (TEM). The dislocations have been subjected to Burgers vector and trace analyses to determine the slip directions and planes with the aid of image simulations generated using single crystal elastic constants derived from first principles calculations. The experimental results are compared to predicted slip directions and planes from anisotropic elasticity calculations. Thermal expansion coefficients have been measured by dilatometry and are compared to both calculated and previous experimental values measured using diffraction techniques. Lastly, preliminary compression testing has been performed on the single phase material at 1200°C.     

Ni-P镀层在RNH_2-CO_2-H_2S-Cl~--H_2O腐蚀环境中的适用性研究

通过模拟某油田再生塔塔底重沸器的腐蚀环境,对304不锈钢和Ni-P镀层进行评价。结果显示:在模拟重沸器腐蚀环境中,105℃气相和液相共存条件下,304不锈钢和Ni-P镀两种材质的均匀腐蚀速率均大于90℃,304不锈钢腐蚀相对轻微,Ni-P镀在两个腐蚀模拟条件下均出现开裂和脱落现象。