撞击流-活性炭吸附法制备氧化钇超细粉体

以Y( NO3)3·6H2O和碳酸氢铵为原料,在撞击流反应器中制备碳酸钇,经焙烧得到超细氧化钇粉体.考察了分散剂加入量、反应物摩尔比n( NH4HCO3)/n(Y(NO3)3)、活性碳用量、反应温度、反应时间、搅拌速度以及碳酸钇的焙烧温度和焙烧时间等因素对Y2O3粒径的影响,并用WJL激光粒度仪、TG、XRD和SEM等表征手段对产品进行表征,从而获得制备超细氧化钇的优化工艺条件为:PEG4000的质量为硝酸钇的3％,活性炭用量为0.025 mol·L-1,反应物摩尔比n( NH4HCO3):n(Y( NO3)3)为8:1,反应温度50℃,反应40 min,螺旋桨转速1000 r·min-1,800℃下焙烧1.5h,在此条件下制得球形氧化钇超细粉体,表观粒径小于0.5μm.     

La_2O_3/La_2O_2CO_3纳米复合材料的凝胶燃烧法合成

采用燃烧法合成了纳米La2O3/La2O2CO3复合材料,以六水合硝酸镧和一水合柠檬酸分别为镧源和络合剂,以氨水调节p H值,p H=2~4、柠檬酸与硝酸镧的摩尔比在1.0~1.2∶1.0之间,将得到的凝胶加热到一定温度发生自蔓延燃烧反应,燃烧反应产物在600~700℃煅烧1~2 h,得到膨松粉末状纳米La2O3/La2O2CO3复合产物。煅烧温度和恒温煅烧时间不同,得到不同粒径和组分比例的纳米La2O3/La2O2CO3复合材料。利用X射线衍射(XRD)、差热-热重分析(TG-DTA)和透射扫描电镜(TEM)等测试方法对凝胶热分解过程产物及最终形成的纳米La2O3/La2O2CO3复合产物粉体进行了分析和表征,产物的平均粒径在30~100 nm之间可控。纳米La2O3/La2O2CO3复合产物中的纳米La2O3在空气中具有不稳定性,极易与空气中的H2O发生反应生成La(OH)3,生成了La(OH)3/La2O2CO3复合产物,而产物在650℃煅烧2 h后即可完全转化为La2O3/La2O2CO3复合产物,说明这个过程是可逆的。     

片状氧化镧粉体的制备及表征

以普通La2O3、硝酸、氨水、聚乙二醇(6000)为原料,利用氨水沉淀法制得了片状氧化镧粉体,利用TG-DSC表征了前躯体氢氧化镧粉末在热分解过程中的变化情况.用激光粒度仪表征了氧化镧粉体的体积百分比与粒径的正态分布,用SEM表征了氧化镧粉体的形貌,用BET法得到了氧化镧的比表面积和当量直径.实验结果表明,在适当的工艺条件下,可以制得片状的氧化镧粉体,比表面积为21m2/g～30 m2/g,当量直径为30.41nm～43.97nm.     

醋酸镧的制备工艺及表征

采用冰醋酸溶解氧化镧工艺制备醋酸镧。考察冰醋酸液酸度、氧化镧与冰醋酸的固液比、溶解温度、溶解时间对醋酸镧浸出收率的影响,同时阐述常温下冰醋酸溶液浸出氧化镧的工艺。结果表明,在醋酸浓度为1.5 mol·L~(-1),氧化镧与冰醋酸的固液比为0.8,溶解温度为65℃,溶解时间为0.5 h的最佳条件下制备的醋酸镧产品组成为La(CH_3COO)_3·H_2O,并对其稀土总量,杂质含量,形貌与结构,热分解机制指标进行检测和表征。     

La2O3纳米晶的制备及表征

以硝酸镧、酒石酸铵为原料,采用络合沉淀法制备了前驱物.前驱物经80℃烘干,用红外光谱,TG-DTA进行了测定,结果表明,前驱物为酒石酸镧络合物La2L3·12H2O.然后置于马弗炉中于650℃、750℃和850℃分别煅烧2h,得到不同粒径的La2O3样品,用XRD、TEM和SEM等测试方法进行了表征,样品的平均粒径分别约为20.67nm、28.14nm和39.55nm.     

镧改性固体催化剂SnO2-WO3/La2O3的制备及其催化性能

500℃焙烧3 h条件下制备了摩尔比nSn∶nW=2∶1,含3.0%(质量分数,下同)La2O3的镧改性固体催化剂SnO2-WO3/La2O3,采用IR分析对其进行了表征。通过改变催化剂用量、30%H2O2用量、反应时间及催化剂重复使用性等因素,系统考察了该稀土改性双金属氧化物催化氧化环己酮合成己二酸的催化性能。实验结果表明,己二酸的适宜合成条件为:100 mmol环己酮,1.25 g催化剂SnO2-WO3/La2O3,50 mL 30%H2O2,回流反应7 h,目的产物己二酸收率达77.7%。SnO2-WO3/La2O3连续使用6次己二酸收率仍可接近40%。     

撞击流反应制备CeO2超细粉体

以Ce(NO3)3·6H2O为原料,碳酸氢铵为沉淀剂,少量表面活性剂作分散剂,撞击流反应制备碳酸铈,经焙烧得到超细二氧化铈粉体.研究了加料方式、硝酸铈浓度、表面活性剂用量、搅拌速率、反应温度、反应时间、陈化时间及碳酸铈的焙烧温度和焙烧时间等因素对CeO2颗粒尺寸的影响,从而得出优化工艺条件.采用WJL激光粒度仪检测二氧化铈的粒径,并且通过TG、XRD和SEM等方法对合成产品进行表征,结果表明,合成的是立方晶系的球形二氧化铈超细粉体,晶粒尺寸为20.5nm.     

(Ce-Zr)mA1-mO2复合氧化物的制备及其表征

以碳酸铵为沉淀剂,采用共沉淀法制备铈锆、铈锆镧、铈锆镨复合氧化物,通过X射线衍射(XRD)、BET法和程序升温还原(TPR)等手段对复合氧化物进行了表征,研究了高温焙烧条件下不同铈锆摩尔比和掺杂镧镨对复合氧化物的结构和性能的影响,并初步分析了掺杂La和Pr的作用机理.结果表明, Ce0.76Zr0.24O2在高温焙烧后仍然保持着立方相的固溶体结构,衍射峰没有发生分裂,有着比较好的高温热稳定性;掺杂La和Pr以后均能在一定程度上提高氧化物的热稳定性.     

钙钛矿型LaMnO3-δ及La1-xSrxMnO3-δ纳米粒子的XPS表征

采用 XPS手段对钙钛矿型 La Mn O3-δ及 L a1- x Srx Mn O3-δ纳米粒子进行了表征 ,结果显示 ,随L a Mn O3-δ纳米粒子粒径减小 ,其表面氧空位浓度增加 ,表面化学吸附氧性质发生变化 ,同时单位质量试样上化学吸附氧含量增加 ,这些导致化学吸附氧反应活性提高 ,使 CO氧化的起始反应温度降低和一定温度下单位质量催化剂上 CO氧化速率提高。 La Mn O3-δ中的镧被锶部分取代后表面氧空位浓度显著提高 ,表面有 Mn3 和 Mn4 共同存在 ,CO氧化的催化活性也明显提高。     

掺杂镧纳米TiO2的制备和结构表征

本文以钛酸四丁酯、无水乙醇、冰醋酸、硝酸镧和水为原料,通过控制原料配比、反应温度、陈化温度、焙烧温度和焙烧时间,采用溶胶-凝胶法制备了纯的纳米TiO2和四种不同镧掺杂量的TiO2纳米粉体。确定的工艺参数为:原料按照体积比为V水∶V钛酸丁酯∶V无水乙醇∶V冰醋酸=17∶17∶80∶15,凝胶干燥温度选择80℃,粉体焙烧温度为500℃。对所得产物分别采用FT-IR和粉末XRD法进行了表征,FT-IR分析结果表明,掺杂La3+后TiO2的红外吸收峰的位置基本没有发生变化,但部分吸收峰明显宽化,表明掺杂镧引起基团间作用力的改变,使基团的存在环境和键的强弱发生变化,从而导致了红外吸收峰宽化。XRD测试得出所制备的纯TiO2和四种不同镧掺杂量的TiO2粉体的结构均为锐钛矿型TiO2,且随着La掺杂量的增加,TiO2的粒径越来越小,从未掺杂时的26 nm减小到掺杂1%镧时的8 nm,说明镧的掺杂有细化晶粒的作用。     

Chinalco Signed Framework Agreement for Strategic Cooperation with Harbin Municipal Government

正Last month,Chinalco signed framework agreement for strategic cooperation with Harbin Municipal Government in Harbin Xiong Weiping,Chairman of Chinalco,said that based on the strategic deployment to build world top-class mining company with the highest growth potential,Chinalco was now concentrating all efforts on making strategic transition and structural adjustment,strategic cooperation with the local governments where     

Jiangxi Promotes Jiangxi Copper Corporation To Become The World's Most Competitive Mining Company

<正>According to the latest info from Jiangxi Province State-owned Assets Supervision and Administration Commission,Jiangxi Copper Corporation was approved to become the first pilot enterprise for deepening reform.Contents of the pilot work is"Three Self"(self expansion,self decision-making,self     

Journal of Rare Earths Contents List of Vol.32(2014)

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Contributions to Baosteel Technical Research wanted

正Baosteel Technical Research,a quarterly journal,which is issued domestically and abroad,is run and sponsored by Baosteel Group Corporation.Baosteel Technical Research mainly reports the achievements in technological innovation,academic research,new product development and industrial equipment improvement by Baosteel.It will continue to follow up on hot topics and serve the company’s technological development and progress.Its readers include experts in     

Ministry of Industry and Information Technology: No Short Term Solution For Our Country’s Excess Nonferrous Metal Smelting Capacity

【正】According to the Ministry of Industry and Information Technology,the Ministry has released the 2013 Operation Report on China’s Industrial Communication Indu...     

Chinalco Signed Framework Agreement for Strategic Cooperation with Gansu Province

正Recently,Chinalco and Gansu Provincial People’s Government signed"Framework Agreement for Strategic Cooperation on Reform,Restructuring and Transition Development of Chinalco’s Electrolytic Aluminum Enterprises in Gansu",signifying that the strategic cooperation between Chinalco and Gansu Province had made new substantive progress.     

Unavoidable Economic Cycle:30% Of Nonferrous Metal Companies Were Involved In Restructuring

正Owing to continual downturn in real estate and bulk commodity markets,a number of traditional industries in China suffered unfavorable impact in performance.With the progressive disclosure of third quarter report,the no-pleasant-surprise performance of     

Baotou Rare Earth Became the World's Biggest High Performance Magnetic Material Base

正The High Performance Magnetic Material Phase II Project,an industry upgrading project implemented by Inner Mongolia Baotou IronSteel Rare Earth(Group)Hi-tech Co.,Ltd,recently basically finished equipment commissioning,signifying that the enterprise had developed the production capacity of15000 t/a Nd-Fe-B strip casting alloy and 5000t/a Nd-Fe-B magnet,thus becoming the world’s     

Introducing Two Central Enterprises to Integrate Rare Earth Industry,Shandong Rare Earth Group Breaks Surface

正With the signing of"Letter of intention for Propelling Integration of Shandong Rare Earth Enterprises"between Shandong Province Commission Of Economy and Informatization,China IronSteel Research Institute Group("China Steel Institute"),and China Rare MetalsRare Earth Co.,Ltd("China Rare Earth"),the"Shandong Rare Earth Group"jointly set up by the 3 units thus broke surface.On August 9,reporters of the China Economic Herald learned from Shandong Province     

Aluminium Production by Province or City in 2014

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