一种制备插层和无定形高岭土的新方法

利用甲醇钠强烈的夺氢作用 ,介绍了一种制备插层和无定形高岭土的方法。利用XRD为主要检测手段研究了甲醇钠的质量分数、反应温度等因素对反应的影响。结果表明 :在反应温度较低、质量分数较低的甲醇钠溶液中 ,高岭土容易被插层而膨胀 ,反之高岭土的层状结构被破坏而无定形化。红外光谱分析进一步证明了插层和无定形高岭土结构的变化     

Dispersion—flocculation studies on a Goethite-clay system

Dispersion–flocculation studies on a Goethite–clay system using flocculants were carried out as a function of flocculant concentrations, pH of slurry, time of agitation and dispersant dosage. Also, the effects of pH and polymer concentrations on the adsorption behaviour of the system were investigated. Results show that well flocculated goethite was preferentially obtained from 4% goethite/kaolinite clay suspensions, with 50 ppm causticised starch in the slurry at pH values of 3–11·5 and with 50 ppm polyacrylamide at pH values of 3–8. Good flocs were also obtained on flocculation of the goethite suspension with 50 ppm polyacrylamide at pH values of 5–7, while the kaolinite suspension did not respond to the same dosage of causticised starch in the same pH range. Results further reveal that for the goethite/kaolinite suspension, the best results was obtained with 50 ppm polyacrylamide at pH values of 7–10. Based on the data generated in the study, it was concluded that causticised starch is a better flocculant than polyacrylamide for goethite suspensions although polyacrylamide is an excellent flocculant for kaolinite suspensions.     

高岭土改性聚酯纤维

介绍了高岭土在改性聚酯中的作用、纤维级高岭土的性质以及改性聚酯的制造方法．指出了我国开发高岭土改性聚酯纤维的的前景．     

A novel depressor useful for flotation separation of diaspore and kaolinite

The floatation of the minerals diaspore and kaolinite was investigated using dodecylamine as the collector.Separating diaspore and kaolinite in a neutral pH pulp is difficult since they then have similar floatability.A depressor consisting of an AlCl3/Na2SiO3 mixture is demonstrated to solve this problem.Diaspore sinking may be seen when the ratio of AlCl3 to Na2SiO3 is 3.1.We refer to this mixture as ATNO.The influence of Al/Si ratio in the feedstock and the grain size of fed minerals on separation was examined.An Al/Si ratio in the concentrate greater than 11 may be obtained when the Al/Si ratio of the feed is between 2.53 and 4.96.However,the grain size of the diaspore greatly influences the concentrate grade.Finer grain size of the diaspore (＜40 μm)in pulp makes the flotation separation less than ideal,no matter what the kaolinite grain size.     

Fabrication of phytic acid embellished kaolinite and its effect on the flame retardancy and thermal stability of ethylene vinyl acetate composites

A modified kaolinite by grafting with phytic acid (PA-g-Kaol) is fabricated, and it was introduced into ethylene vinyl acetate (EVA) with intumescent flame retardancy (IFR) together to improve the flame retardancy of EVA composites. The results show the limiting oxygen index value of EVA/ (18.0 wt% IFR)/ (2.0 wt% PA-g-Kaol) is 30.8%. Meanwhile, there is only one dripping produced in the vertical burning test. What's more, the flame-retardant mechanism is demonstrated by TG-IR, real-time-IR and GC–MS analysis. The results indicate that some pyrolytic products of IFR and PA-g-Kaol, like ammonia and phosphoric acid, catalyze the crosslinking of EVA and flame retardant, the resultant compact char protects the substrate from further burning.     

高岭石脱水反应的非等温热重法研究

在系统分析非等温固相反应特点的基础上,建立了非等温脱水反应速率方程.采用非等温热重法、通过计算机辅助计算,对高岭石脱水反应动力学规律进行了研究.结果表明:由于高岭石晶体结构中内、外羟基脱除的顺序不同,其脱水反应机制在反应分数(α)为0.7左右时发生改变.在反应前期(0＜α＜0.7)时,脱水反应遵循二维扩散控制规律,脱水反应表观活化能为159.682 kJ/mol、表观频率因子为1.007×10 10/min.     

Study on Adsorption of Rare Earth Elements by Kaolinite

Rareearthelements (REEs)werewidelyappliedtotracingthesourcesofmaterialsandtostudyingtheirevolutionprocessesinmanyfieldsofearthscienceinconsiderationoftheirsimilarityandsystematicdiffer enceinchemicalproperties .Furthermore ,lanthanidesarebothimportantprod…     

微波对制备高岭石插层作用的研究

为了明确微波对制备高岭石插层的作用,采用乙酰胺对高岭石的微波熔融插层和油浴熔融插层进行了对比实验.借助于XRD、FTIR等分析测试手段,通过对比不同时间段2种插层环境下的插层率,分析了微波对插层反应的影响,进而探讨了微波对插层反应的作用机理.研究发现在反应初期微波对插层反应起促进作用,但随着时间的延长这种促进作用减弱,并呈现出一定的阻碍作用,认为是微波对乙酰胺的热作用和极化作用综合作用的结果.     

纳米银粒子在高岭石层间的合成与表征

以高岭石-二甲基亚砜作为前驱体,用硝酸银层间取代,以高岭石的层间作为反应器来控制银粒子的大小,采用还原剂水合肼还原出单质银,制备高岭石-纳米银复合物。由红外光谱研究可知,插层作用破坏了层间氢键,二甲基亚砜与高岭石的外羟基形成了氢键,银的插入使得高岭石在2θ=38.1108～38.3942°之间出现了一个陡峭Ag(111)的衍射峰。TEM研究表明,Ag已进入层间,但粒度分布不均匀。