邻苯二甲酸盐(Sr2+)的制备及热分解反应研究

合成了邻苯二甲酸盐(Sr^2 )，用热重(TG)和示差扫描量热(DSC)法研究了邻苯二甲酸盐的热分解过程．一水合邻苯二甲酸锶的热分解过程分为4个阶段：在57～140℃脱水生成无水盐；在510～610℃分解生成Sr3(C8H4O4)(CO3)2；在610～860℃分解生成Sr3O2CO3；在860—1390℃分解生成单质Sr．分解的气相产物有邻苯二甲酸酐，9，10—蒽醌和CO2，     

青山铅锌矿床两种热液混合成矿的锶同位素证据

对青山铅锌矿的锶同位素测试表明它的组成符合二元混合模型，通过其他地质与地球化学的研究表明本区铅锌矿系由两种成矿溶液混合形成的。     

二水甲酸锶晶体生长机制

采用静态体视显微法测定了在３．０３．１５Ｋ下，二水甲酸锶晶体的（１１０）和（０１１）面的生长速率，通过用生长速率（Ｒ）与过饱和度（σ）的关系，计算了生长参数，发现其生长机制符合水溶液中晶体生长的ＢＣＦ面扩散模型。研究了体扩散对生长速率的影响，结果表明：在低过饱和度下，体扩散影响很小，当过饱和度σ≥０．２００时，体扩散影响显著。     

碳酸氢铵法(不除钡)生产碳酸锶

反应体系的热力学性质表明:文题的复分解反应是一弱放热反应;可以加入SC_4~(2-)离子以抑制BaSO_4转化为BaCO_3;加入氨水可以提高碳酸氢铵溶液的稳定性。把SrSO_4和BaSO_4含量分别为81.40%、7.93%的天青石经盐酸处理后与碳铵溶液混合。结果表明,在碳铵用量为化学计量比的1.3倍,反应时间3h,反应温度60℃下,矿石转化率可达90%以上。精制过程不需除钡,产品中SrCO_3含量98.83%,BaCO_3含量0.138%。     

热重法研究一水合草酸锶脱水过程的机理与动力学

本文利用等温热重法和非等温热重法,研究了一水合草酸锶脱水过程的机理与动力学.实验测定和理论分析表明:SrC_2O_4·H_2O的脱水过程受A_3机理支配,即属于一种随机成核和晶核随后生长的过程,其活化能E=94.47kJ·mol~(-1),频率因子A=2.59×10~(10)min~(-1).     

钛酸锶的合成与结构分析

本文用四氯化钛、二氯化锶为原料,以氢氧化钠为沉淀剂,得到了钛和锶的氢氧化物共沉淀。然后,在水溶中于90℃反应4小时,产品经洗涤、过滤、干燥,得到钛酸锶粉末。产品经x射线分析,证明为立方晶系,P_(m3m),空间群。晶胞参数a=3.917A°。产品经扫描电镜观察,发现粒子外观基本呈球形,粒径分布均匀,大小在0.2μ左右。光电子能谱分析表明,产品中不含其他杂质离子。另外,本文还就沉淀剂的量、反应时间、反应温度、反应摩尔比等对产品的影响进行了研究。     

微晶粉粒铁电相变中的介电常数

提出了一个理论模型说明现行方法不能观察到微晶粉粒铁电相变介电峰的原因。按照理论预言 ,测量了钛酸锶钡粉料与水混合成两相不均匀系的相变介电峰 ,实验结果与理论公式符合得很好     

Facile synthesis of CoFe2O4 nanoparticles anchored on graphene sheets for enhanced performance of lithium ion battery

Recently, metal oxides as high capacity anode materials had been investigated for lithium ion batteries.However, the fast capacity fading upon cycling leaded poor durability, which hindered their application as higher energy density of lithium ion battery. In this paper, a nanostructured nanocomposite with graphene supported CoFe_2O_4 nanoparticles(NPs) was prepared via simple hydrothermal reaction. The uniform CoFe_2O_4 NPs were anchored on graphene sheets, which brought a good performance on cyclability. Combined with the optimization of graphene content, the anode delivered a better capacity retention of 944 m A h g~(-1)over 50 cycles at current density of 100 m A g~(-1)and the good reversible capacity as 990 m A h g~(-1)when the rate returned from 5 A g~(-1)to 0.1 A g~(-1)after 60 cycles. The present work provided a desired structure for conversion anode materials or other electrode materials of large volume change.     

Cost-effective integrated strategy for the fabrication of hard-magnet barium hexaferrite powders from low-grade barite ore

Ultrafine barium hexaferrite (BaFe₁₂O₁₉) powders were synthesized from the metallurgical extracts of low-grade Egyptian barite ore via a co-precipitation route. Hydrometallurgical treatment of barite ore was systematically studied to achieve the maximum dissolution efficiency of Fe (~99.7%) under the optimum conditions. The hexaferrite precursors were obtained by the co-precipitation of BaS produced by the reduction of barite ore with carbon at 1273 K and then dissolved in diluted HCl and FeCl₃ solution at pH 10 using NaOH as a base; the product was then annealed at 1273 K in an open atmosphere. The effect of Fe3+/Ba2+ molar ratio and the addition of hydrogen peroxide (H₂O₂) on the phase structure, crystallite size, morphology, and magnetic properties were investigated by X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. Single-phase BaFe₁₂O₁₉ powder was obtained at an Fe3+/Ba2+ molar ratio of 8.00. The formed powders exhibited a hexagonal platelet-like structure. Good maximum magnetization (48.3 A·m2·kg–1) was achieved in the material prepared at an Fe3+/Ba2+ molar ratio of 8.0 in the presence of 5% H₂O₂ as an oxidizer and at 1273 K because of the formation of a uniform, hexagonal-shaped structure.