硫酸钙晶须表面湿法改性研究

采用几种表面改性剂对硫酸钙晶须表面进行了湿法改性试验,选出了改性效果较好的硬脂酸对硫酸钙晶须进行了单因素条件改性试验,分别考察了改性剂用量、初始料浆浓度、改性温度、改性时间、搅拌速率、烘干温度、烘干时间等因素对硫酸钙晶须表面改性的影响;改性硫酸钙晶须产品采用活化指数、接触角、扫描电子显微镜、X射线衍射和红外光谱分析进行表征。试验结果表明:硬脂酸对硫酸钙晶须的改性效果较好,在最佳工艺条件下,改性产品的活化指数为1.00,接触角为123.6°。建立了硬脂酸与硫酸钙晶须的作用模型。     

硫酸钙晶须改性及其对纸张性能的影响研究

采用六偏磷酸钠对自制硫酸钙晶须进行表面湿法改性,考察了六偏磷酸钠对硫酸钙晶须的溶解抑制效果及改性硫酸钙晶须作为纸张填料对纸张物理性能的影响。研究表明,六偏磷酸钠对硫酸钙晶须有较好的改性效果,明显抑制了硫酸钙晶须的溶解;在抄纸过程中加入20%以上改性硫酸钙晶须制得的纸张白度均超过91%;当改性硫酸钙晶须添加量为30%时,晶须在纸张中分布均匀,纸张的各项物理性能满足一般印刷纸张的质量要求。     

表面改性硫酸钙晶须在PP材料中的应用研究

用硬脂酸钠作为表面改性剂对硫酸钙晶须表面改性,通过双螺杆挤出机与注塑机造粒制样条,得到CSW/PP复合材料。研究了改性用高混机搅拌转速与硫酸钙晶须添加量对CSW/PP复合材料力学性能的影响。试验结果表明:高速混合机转速为40Hz时,CSW/PP复合材料的断裂拉伸应变提高62%,但拉伸强度与弯曲强度略有降低;晶须添加量为10%时,CSW/PP复合材料的断裂拉伸应变提高55.6%;添加量为30%时,弯曲模量提高179%,弯曲强度略提高,拉伸强度略有降低;经过表面改性可改善硫酸钙晶须与PP之间的相融性。     

碱式硫酸镁晶须表面改性研究

为了改善碱式硫酸镁晶须的表面性质,提高碱式硫酸镁晶须与有机基体材料的相容性,以活化指数和接触角为改性效果评价指标,采用化学包覆法对自制的碱式硫酸镁晶须进行了表面改性研究。结果表明：适于碱式硫酸镁晶须表面改性的改性剂为油酸钾;在油酸钾用量为2%、改性晶须料浆浓度为4%,改性时间为30 min,改性温度为80 ℃,搅拌速度为600 r/min条件下,可以获得较好的表面改性效果,改性碱式硫酸镁晶须的活化指数达到99.35%,接触角为126.8°。     

大长径比硫酸钙晶须的制备及形貌研究

以天然石膏为原料采用水热法制备半水硫酸钙晶须,SEM观察晶须形貌及分析长径比。考察了外加剂、原料粒度、水热温度、pH值、初始料浆浓度、水热时间对硫酸钙晶须形貌影响。结果表明:外加剂提高了天然石膏在水中的溶解度;原料粒度会影响天然石膏的溶解速率,粒度越小溶液越容易达到过饱和状态;水热温度在 < 100 ℃时较难生成硫酸钙晶须;溶液pH值可改变溶液离子质量分数,随着pH值升高晶须平均直径逐渐减小,同时会导致外加剂失效;料浆浓度越高,晶须生长空间越小,溶液体系离子迁移速度降低。在原料粒度4 μm、料浆浓度5%、CuCl₂ 1.5%（相对于天然石膏质量）、水热温度120 ℃、pH=5.3、水热时间140 min的条件下,制备出平均直径1~2 μm、长径比达160的半水硫酸钙晶须。      

氢氧化镁晶须表面改性及应用研究

为提高氢氧化镁晶须与基体材料的相容性,研究了氢氧化镁晶须的表面改性技术,结果表明:氢氧化镁晶须较适宜的改性条件是以硬脂酸钠为表面改性剂,改性剂用量2%(按晶须粉体干重计),料浆浓度5%,改性时间30 min,改性温度80 ℃,搅拌速度600 r/min.在此条件下,氢氧化镁晶须的活化指数可达到99%,接触角为108.6°.将改性后的氢氧化镁晶须添加到聚丙烯基体中制成复合材料,研究氢氧化镁晶须的增强和阻燃作用,并与水镁石粉体作添加剂进行对比,结果表明:前者氧指数提高4.7%,断裂强度提高64.71%,弯曲模量提高78.6%,断裂伸长率降低315.58个百分点.     

改性硫酸钙晶须/聚丙烯复合材料力学性能研究

用硬脂酸作为表面改性剂,通过双料口加料方法制得硫酸钙晶须/聚丙烯复合材料,研究了硫酸钙晶须添加量对复合材料力学性能的影响。试验结果表明:当硫酸钙晶须添加量为8%时,拉伸强度达到最大值,较纯pp拉伸强度提高了3.49%;当硫酸钙晶须添加量为12%时,弹性模量达到最大值,为1.451 GPa,较纯pp提高了16.5%;当硫酸钙晶须添加量为12%时,断裂伸长率为27.46%,比纯pp下降了41.74%;硫酸钙晶须添加到2%时,缺口冲击强度有较大提高,比纯pp提高了36.2%。     

金属离子对硫酸钙晶须形貌影响的试验研究

以脱硫石膏为原料制备硫酸钙晶须,研究反应温度、反应时间、金属离子的种类和浓度对硫酸钙晶须形貌、尺寸的影响。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)等手段对硫酸钙晶须物相及形貌进行表征。结果表明:反应温度、反应时间、金属离子的种类和浓度都会影响硫酸钙晶须的形貌。制备硫酸钙晶须的最佳工艺条件为:浆料质量分数为2%,反应时间为90 min,硫酸浓度为2 mol/L,搅拌速率为150 r/min,氯化镁为晶型控制剂(浓度为17 mmol/L),所制备出硫酸钙晶须的平均长径比为148,平均直径2.2μm。Mg2+通过吸附在晶体的表面对硫酸钙晶须的形貌产生影响,而Al3+对硫酸钙晶须的形貌影响是其被纳入晶体造成。     

纳米碳酸钙表面改性研究

采用硬脂酸对纳米碳酸钙进行改性,并对改性产品进行了表征。硬脂酸湿法改性纳米碳酸钙的最佳条件为硬脂酸用量为2 5%,料浆浓度为9%,改性温度为90℃,改性时间为40min,搅拌速率为2500r/min,烘干温度为100℃;所得改性纳米碳酸钙产品的活化指数达0 94以上,白度在96%以上。活化指数测定结果表明,改性后的纳米碳酸钙由亲水疏油性变成了亲油疏水性;IR分析表明硬脂酸与纳米碳酸钙以化学键结合。     

反应条件对脱硫石膏晶须生长行为的影响

以脱硫石膏为原料,采用水热法工艺制备硫酸钙晶须。借助XRD、高分辨显微镜等分析方法,深入探讨了反应温度和反应时间对硫酸钙晶须生长过程的影响。结果表明:利用脱硫石膏可以制备出硫酸钙晶须;随着反应温度的升高和反应时间的延长,硫酸钙晶体的长径比呈先升高后降低的趋势;当反应温度为140℃、反应时间为120min时,长径比达到最大,其值为48.17。     

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     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586