利用东海蛇纹石合成堇青石的研究

以东海蛇纹石粉、α-Al2O3粉和石英粉为原料,通过高温固相合成法,在不同烧结温度下对试样进行烧结,并测试试样的烧结收缩率、体积密度、吸水率、显气孔率、烧失率和抗折强度。研究表明:在烧结温度为1 150℃时,未观察到有堇青石生成;在1 200℃时,有少量堇青石生成,并伴有镁铝尖晶石;温度为1 225℃时,有大量的堇青石生成,吸水率为12.55%,显气孔率为24.93%,体积密度为1.99g/cm3,抗折强度为35.33MPa;继续升温到1 250℃,生成的堇青石有部分熔融。     

微/纳米双尺度混杂颗粒增强铝基复合材料的制备工艺

采用粉末真空热压烧结机,将微米尺度的SiC颗粒、Al-Si合金基体粉末与反应剂CuO粉末混合后加热到一定温度,使CuO与Al发生原位反应,生成纳米尺度的Al2O3颗粒,然后冷却、热压,制得(微米SiC+纳米Al2O3)/Al-Si双尺度混杂颗粒增强铝基复合材料,并对复合材料进行热处理强化。研究了不同的原位反应加热温度、热压温度、热压压力对复合材料组织、硬度及磨损性能的影响。结果表明,采用微米SiC及纳米Al2O3混杂颗粒强化、热压强化、热处理强化等强化后制备的铝基复合材料具有较高的硬度及耐磨性。原位反应加热温度为620℃、热压温度510℃、热压压力3MPa时,复合材料试样组织细小致密,硬度及耐磨性最好,复合材料的磨损机制主要为磨粒磨损。     

铝硅酸盐纤维增强Al2O3-SiO2复合材料的制备与性能研究

对Al2O3-SiO2凝胶的无机化与烧结特性进行了研究,结果表明:Al2O3-SiO2凝胶主要由勃姆石(boehmit)和无定形SiO2组成,经500℃煅烧后boehmit分解形成γ-Al2O3,1200℃煅烧后γ-Al2O3转变为(δ,θ)-Al2O3,1300℃煅烧后(δ,θ)-Al2 O3和无定形SiO2反应生成莫来石(mullite);随着烧结温度的升高,Al2O3-SiO2陶瓷的收缩率逐渐升高,孔隙率逐渐降低,相对密度逐渐升高.采用溶胶-凝胶工艺制备了三维铝硅酸盐纤维增强Al2O3-SiO2复合材料,并对热处理温度进行了优化,研究结果表明:随着热处理温度的升高,复合材料的弯曲断裂模式逐渐由韧性断裂转变为脆性断裂,复合材料断面拔出纤维长度逐渐缩短直至消失;热处理温度为1100℃时制备的复合材料的力学性能最优,其弯曲强度、剪切强度和断裂韧性分别为90.0±6.8 MPa,11.1±1.0 MPa和3.6士0.2MPa·m1/2.     

堇青石基透波材料的试验研究

采用Mg O、Al2O3与Si O2作为原料按照一定配比进行混合,将混合后原料通过微波烧结合成堇青石基透波材料,并考察不同的微波烧结温度对所得样品的物相、介电性能、显气孔率及体积密度的影响。试验结果表明,提高微波烧结温度有利于堇青石相的生成;随温度的升高样品的致密度增大,介电常数变大,同时,陶瓷材料内部分镁铝尖晶石相转变为堇青石相,使得介电常数变小,1 350℃材料的介电常数最高;随着烧结温度的升高,样品的显气孔率逐渐降低,体积密度逐渐增大。     

In2O3纳米球的制备及其在黄药气体检测中的应用

为了实现对浮选过程中挥发出的黄药气体的有效检测，采用水热法制备了 In2O3纳米球，考察了水热 时间和热处理温度对最终制备产物形貌和结构的影响。结果表明，在水热时间和热处理温度分别为 2 h 和 400 ℃ 的条件下，可获得粒径小、分散性好和结晶性优良的 In2O3纳米球，其直径为 100~200 nm，由六方相 In2O3晶体颗粒构 成。以该 In2O3纳米球为气敏材料制备了黄药气体传感器，气敏测试结果表明，In2O3纳米球在最佳工作温度 300 ℃ 时可获得对黄药气体的最大灵敏度，其灵敏度与黄药气体浓度之间呈现出较好的线性关系，同时也具有优异的反 应可逆性、稳定性和可重复性。     

MgO对铁矿粉烧结液相生成的影响

在准化学平衡条件下,采用相平衡法研究了不同温度及Al2O3含量条件下,MgO对Fe2O3-SiO2-CaO-Al2O3-MgO五元系内铁酸钙生成过程的影响。利用X射线衍射和偏光显微镜分别对试样进行了矿物定量及矿相结构分析。实验结果表明:R=1.8的烧结试样中,添加MgO对铁酸钙的生成及晶型有一定影响;随着温度升高,铁酸钙生成量明显增加,矿相结构分布趋于均匀,固液相之间胶结逐渐紧密;1300℃时MgO含量变化对促进铁酸钙的生成作用较明显;1350℃时MgO含量变化对矿相微观结构转变起明显作用,特别是对铁酸钙的晶型有较大影响。     

磁化焙烧产品冷却氧化过程中的相变行为研究 —褐铁矿

磁化焙烧工艺作为处理难选铁矿资源的有效工艺,近年来在铁矿资源开发中的应用研究取得了巨大进展。在铁矿磁化焙烧的工业化生产中,焙烧产品的冷却是影响焙烧产品品质的重要环节。以西北某矿区褐铁矿为研究对象,通过拣选—强磁选—重选流程得到纯度为 92.0% 以上的褐铁矿作为试验物料进行磁化焙烧,考察了惰性气氛冷却、水淬冷却、空气气氛冷却对焙烧产品的影响,深入研究了空气气氛冷却方式下,焙烧产品在不同氧化温度、氧化时间条件下的氧化行为和相变情况。结果表明：焙烧产品在惰性气氛和水淬方式冷却过程中基本不发生氧化反应;在空气冷却方式下,氧化温度和氧化时间对褐铁矿磁化焙烧矿产品影响显著;在氧化温度为 100 ℃ 时,焙烧产品基本不发生氧化。在氧化温度高于 300 ℃时,焙烧产品开始发生明显氧化。氧化温度为 400 ℃、氧化时间 2.0 min 时,焙烧产品中的磁铁矿全部被氧化。磁化焙烧产品氧化后生成 α-Fe2O3和 γ-Fe2O3两种铁物相,在氧化反应过程中先生成 γ-Fe2O3,后生成 α-Fe2O3。试验结果可以为褐铁矿磁化焙烧工艺的优化提供参考。     

磁化焙烧产品冷却氧化过程中的相变行为研究 —褐铁矿

磁化焙烧工艺作为处理难选铁矿资源的有效工艺，近年来在铁矿资源开发中的应用研究取得了巨大进展。在铁矿磁化焙烧的工业化生产中，焙烧产品的冷却是影响焙烧产品品质的重要环节。以西北某矿区褐铁矿为研究对象，通过拣选—强磁选—重选流程得到纯度为 92.0% 以上的褐铁矿作为试验物料进行磁化焙烧，考察了惰性气氛冷却、水淬冷却、空气气氛冷却对焙烧产品的影响，深入研究了空气气氛冷却方式下，焙烧产品在不同氧化温度、氧化时间条件下的氧化行为和相变情况。结果表明：焙烧产品在惰性气氛和水淬方式冷却过程中基本不发生氧化反应；在空气冷却方式下，氧化温度和氧化时间对褐铁矿磁化焙烧矿产品影响显著；在氧化温度为 100 ℃ 时，焙烧产品基本不发生氧化。在氧化温度高于 300 ℃时，焙烧产品开始发生明显氧化。氧化温度为 400 ℃、氧化时间 2.0 min 时，焙烧产品中的磁铁矿全部被氧化。磁化焙烧产品氧化后生成 α-Fe2O3和 γ-Fe2O3两种铁物相，在氧化反应过程中先生成 γ-Fe2O3，后生成 α-Fe2O3。试验结果可以为褐铁矿磁化焙烧工艺的优化提供参考。     

烧结温度对刚玉斜锆石复相陶瓷粉体的性能影响

以ZrOCl2·8H2O和AlCl3·6H2O为主要原料,采用溶胶-凝胶法制备化学成分均匀的刚玉斜锆石复合粉体,研究了不同焙烧温度对复合粉体体积密度、烧成收缩以及抗弯强度的影响,采用X射线衍射(XRD)、扫描电镜(SEM)测试手段分析了不同烧结温度下所得试样的矿物组成和微观结构.结果表明,随着烧结温度的提高,试样收缩率变大,烧结体密度不断增大,晶粒尺寸均匀,当烧成温度为1400℃时,复合粉体获得了最佳力学性能,抗弯强度达620 MPa,当烧成温度为1600℃时,其体积密度最大为5.1 g/cm3,并形成了结晶完好的刚玉斜锆石复相陶瓷粉体.     

纳米LiMn2O4的制备

以硝酸锂、硝酸锰为原料,柠檬酸作为络合剂,采用溶胶一凝胶法获得前驱体,然后将前驱体在空气气氛中焙烧制备了纳米LiMn2O4。采用DTA-TG对前驱体的热分解行为进行了研究,用XRD考察了合成产物的结构和纯度,用SEM对合成产物进行了形貌观察和尺寸测量,并采用氧化一还原返滴定方法测定了合成产物中锰的平均化合价。试验结果表明,在300℃时已有明显的尖晶石LiMn2O4相出现;经300℃预处理后产物的质量明显提高;合成产物的粒度和晶格常数随温度升高而增加;预处理后合成产物的形貌呈球形,颗粒尺寸在30nm左右且分布均匀;锰的平均化合价为3．498与理论值吻合的较好。     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.