原位生成Al(OH)_3凝固天然橡胶的性能研究

将AlCl3与氨水溶液添加到天然胶乳中原位生成Al(OH)3凝固天然橡胶,通过扫描电镜观察Al(OH)3在橡胶中的分布情况并研究了不同Al(OH)3含量对天然橡胶硫化性能、物理力学性能及热稳定性的影响。结果表明,Al(OH)3对天然橡胶的硫化性能影响较大,且能提高天然橡胶的成炭率,反应生成量为15份Al(OH)3时其分散均匀且所得的胶料的性能优异。     

特种丁腈橡胶耐磨性能研究

采用阿克隆磨耗试验机研究了在干摩擦定载荷条件下经添加八类粉体和三类干膜润滑剂涂膜的硫化丁腈橡胶的滑动磨损性能,用SEM观察磨损试样表面形貌,并通过红外光谱分析了涂膜磨损前后结构特征。结果表明:添加PTFE和Al(OH)3的橡胶试样耐磨性较优,其总磨损量由0.314g分别降低为0.264g和0.272g,分别下降16%和13%;而添加石墨或MoS2磨损质量分别增加20%和63%;添加Al(OH)3并涂覆PTFE和未添加Al(OH)3并涂覆MoS2的试样磨损量较低,二者与涂膜表面特性相关。     

无机填料对环氧模塑料导热和阻燃性能的影响

采用两种无机填料Si₃N₄和Al(OH)₃ 复合填充环氧树脂制备了环氧模塑料(EMCs), 研究了两种填料用量及单独添加和复合添加对环氧模塑料导热性能和阻燃性能的影响。研究结果表明, 单独添加Si₃N₄或Al(OH)₃对环氧模塑料导热性能和阻燃性能的影响规律基本一致, 即随着填料含量的增加, 环氧模塑料的导热性能和阻燃性能均有不同程度的提高; 复合添加Si₃N₄和Al(OH)₃对环氧模塑料的导热性能和阻燃性能均起到积极作用, 但是随着填料中Si₃N₄与Al(OH)₃体积比的变化, 材料导热性能与阻燃性能会产生交叉耦合作用。当 填料中Si₃N₄与Al(OH)₃体积比为3∶2, 总体积分数为60%时, 环氧模塑料的导热率可以达到2.15 W/(m·K), 氧指数为53.5%, 垂直燃烧达到UL-94 V-0级。      

助磨剂对石煤提钒尾渣超细粉磨的影响

采用搅拌磨对钒尾渣进行超细粉磨,考察4种助磨剂的助磨效果,确定最合适的助磨剂为焦磷酸钠,对焦磷酸钠助磨产品的粒径分布、表面电位、表面吸附特性以及颗粒形貌等进行测定分析。结果表明,搅拌磨制备钒尾渣微粉的最佳参数为:添加焦磷酸钠质量分数为1.8%,矿浆质量浓度为1 g/mL,粉磨30 min,所得产品D_(50)=7.85μm、D_(90)=19.78μm,相比未添加焦磷酸钠的磨矿产品D_(50)、D_(90)分别减小了2.97、8.47μm,粉磨时间缩短至少10 min。焦磷酸钠通过在钒尾渣颗粒表面的吸附,增大颗粒的表面电位,减少微细颗粒在表面的粘附,降低矿浆黏度,从而提高钒尾渣的粉磨效率。     

NaAl(OH)2CO3阻燃晶须的水热合成及其阻燃性能

以异丙醇铝和NaHCO3为原料,采用水热法制备了片钠铝石(NaAl(OH)2CO3)晶须,通过XRD、SEM对不同水热条件下合成产物的物相和形貌进行了表征.结果表明,制备的NaAl(OH)2CO3晶须长度为10～20μm,长径比为20～40;初始反应体系的pH值、反应物Na/Al摩尔比、反应温度和反应时间对产物的生长、形貌及尺寸分布有显著影响.添加40%(质量分数)NaAl(OH)2CO3晶须的阻燃EVA,极限氧指数为33.5,垂直燃烧达FV-1,说明NaAl(OH)2CO3晶须具有良好的阻燃性能.     

利用膜气液接触器制备纳米材料的研究

利用膜气液接触器制备了纳米CaCO3、SrCO3、Al(OH)3和Al2O3粒子.根据气液反应理论预测了Ca(OH)2浓度、CO2分压等对CO2吸收速率的影响规律,并得到了实验验证.在实验条件下,Ca(OH)2浓度和CO2分压对CaCO3粒子的形貌影响较小,粒径约为70nm.添加PVP和PEG后,粒度降为48nm左右,分散性明显提高.所得SrCO3纳米粒子为球形,粒度均匀,Sr(OH)2浓度对粒子粒度具有明显影响.Al(OH)3粒子为球形,50nm左右,煅烧后得到Al2O3,粒子尺寸增加至70nm左右.反应后用稀盐酸清洗膜使之再生,膜重复使用9次,膜传质系数未见明显降低.     

环保型阻燃组合木材料的制备与性能

为了获得环保型阻燃组合木材料,利用桉木旋切单板、酚醛树脂胶黏剂、Mg(OH)2阻燃剂制备阻燃组合木试样,通过拉伸试验、扫描电子显微镜、极限氧指数、热重分析对材料进行力学性能、阻燃性能测试和分析。结果表明,适量添加Mg(OH)2可以明显提高复合材料的胶合强度和阻燃性能;当添加Mg(OH)2的质量为胶黏剂固含量(胶黏剂干基质量)的1.2倍时,材料胶合强度增大48.1%,阻燃体系的极限氧指数达到36.3%;通过Mg(OH)2、Al(OH)3复配,极限氧指数进一步增大至38.7%,阻燃性能进一步提高。     

海水中Al（OH）3对稀土铝热浸镀层腐蚀行为的影响

目前有关热浸镀铝层在海水中形成的初级腐蚀产物Al（OH）3对镀层后续腐蚀影响的研究较少。向海水中添加Al（OH）3使其饱和,将Q235钢稀土铝热浸镀试样浸入其中,采用失重法、扫描电镜（SEM）、极化曲线和交流阻抗谱研究了海水中Al（OH）3对稀土铝热浸镀层腐蚀行为的影响。结果表明：热浸镀试样在添加了Al（OH）3的海水...     

平板式ITSOFC用Al2O3基压密封材料研究

以Al2O3和Al微粉为主要原料,采用流延成型工艺生产的Al2O3基密封材料,在模拟的平板式ITSOFC密封环境中对材料的密封性能进行测试,并借助X射线衍射仪、扫描电子显微镜对测试后的材料进行表征.结果表明,采用优化的流延成型工艺可以生产出柔韧性良好的Al2O3基密封材料. Al2O3基密封材料在较小的外加压力下表现出较好的密封性能. Al微粉的加入,减少了材料中的漏气通道,增加了漏气通道的弯曲程度,不仅提升了材料的密封效果,而且改善了材料的中期稳定性.采用流延成型含10wt%～20wt%Al微粉的Al2O3基密封材料以压密封方式来实现平板式ITSOFC的密封是可行的.     

陶瓷微滤膜洗涤碱法制备Al(OH)3中杂质Na+的研究

采用无机陶瓷微滤膜,以错流过滤方式对工业上碱法生产的Al(OH)3粉体浆料进行Na^ 离子的清洗过滤研究．实验考察了操作压力、错流速率、浆料浓度等工艺参数的影响,确立了适合于超细粉体膜清洗过滤的工艺条件．经过陶瓷膜洗涤过滤过程,Al(OH)3粉体粒子仍保持其原始形貌,但粉体的分散性和纯度获得大幅度提高,膜清洗后的Al(OH)3粉体中Na2O含量降为57mg／kg;粒径尺寸约为50nm．研究结果表明,膜清洗过滤效率、操作方式以及产品质量等方面均明显优于目前工业生产上普遍应用的板框压滤机,为无机陶瓷微滤膜技术应用于碱法制备Al(OH)3工艺中的洗涤过滤提供了科学与工程化依据．     

钢渣超微粉/橡胶复合材料的性能及补强-阻燃机制

以磁选热闷渣、未磁选热闷渣、电炉渣和风淬渣作为研究对象,以乙二醇、三乙醇胺和无水乙醇制备钢渣助磨剂,钢渣助磨剂与钢渣进行复合获得钢渣超微粉。将钢渣超微粉与炭黑N220、促进剂、硫磺、 ZnO、硬脂酸、天然橡胶进行复合,制备钢渣超微粉/橡胶复合材料。研究钢渣种类和钢渣助磨剂用量对钢渣超微粉/橡胶复合材料力学性能和阻燃性能的影响。利用XRF、 XRD、 LPSA和FTIR对化学成分、矿物组成、粒度分布和组成结构进行测试。结果表明,以电炉渣制备的钢渣超微粉/橡胶复合材料的力学性能最佳,以磁选热闷渣或未磁选热闷渣制备的钢渣超微粉/橡胶复合材料的阻燃性能最佳。钢渣助磨剂可以减小钢渣超微粉的粒度尺寸,改善钢渣超微粉的粒度分布均匀程度。随着钢渣助磨剂用量的增加,钢渣超微粉的粒度分布均匀程度改善,钢渣超微粉/橡胶复合材料的力学性能提高,阻燃性能降低。     

KHM170型卧辊磨制备钢渣超细粉工业试验研究

基于KHM170型卧辊磨的钢渣超细粉制备终粉磨工业试验系统,在给定钢渣粉、矿渣粉、水泥熟料粉的质量和粒度范围内,进行用钢渣粉部分代替矿渣粉制作水泥混凝土的强度试验。结果表明,KHM卧辊磨终粉磨系统可以实现钢渣超细粉终粉磨,可用于以热焖渣、滚筒渣为原料制备钢渣微粉的工业化生产;矿渣粉中掺加质量分数不超过30%的钢渣粉,且在满足钢渣粉比表面积大于矿渣粉比表面积和水泥熟料粉比表面积时,可以作为优选的混合材料大量用于混凝土。     

Practical strategy to produce ultrafine ceramic glaze: Introducing a polycarboxylate grinding aid to the grinding process

In this work, a polycarboxylate comb-like polymer was used as grinding aid for ceramic slurry, and the effect of addition of this grinding aid on ceramic process property was highlighted. The grinding efficiency of the polycarboxylate grinding aid (PG) in terms of the particle size distribution and specific surface of unit volume of the ceramic slurry being ground were investigated. Consequently, the PG that was synthesized via free radical polymerization under the condition of an APEG/AA/MA molar ratio of 0.3:1:1, an initiator dosage of 5 wt%, and a reaction time of 6 h at 90 °C, provided better grinding efficiency than those of the triethanolamine and other commercial grinding aids. Specifically, with a dosage of 0.21% and 2 h of grinding, the d₉₇ and d₅₀ of ceramic slurry decreased from 13.956 μm and 2.043 µm to 3.739 µm and 0.561 µm, respectively. The cumulative distribution, frequency distribution and SEM results exhibited a uniform particle size distribution for ceramic ground with PG-C. Furthermore, the sintering experiment indicated that a lower processing temperature was capable of producing ultrafine ceramic. These improvements indicated the potential application of the PG as an efficiency ceramic grinding aid, which further facilitating the preparation of uniform ultrafine slurry by a sand mill.     

助磨剂对煅烧高岭土在振动磨中粉体流动度的影响

为解决用振动磨进行煅烧高岭土的细磨过程中常出现磨机出料困难的问题,采用实验室的振动磨进行粉体流动度实验,通过添加不同种类和用量的助磨剂改善振动磨粉体的流动度,以改善振动磨内粉体的研磨效果。结果表明,煅烧高岭土的最佳研磨时间为40 min左右,当研磨时间超过40 min时,产品的颗粒粒度不会变得更细;加入助磨剂后,粉体在振动磨中的流动度得到改善,同时也能使产品的细度得到有效调整;有机助磨剂对流动度的影响明显好于无机助磨剂,但助磨剂的用量必须控制在合适的范围才能使流动度达到最佳指标;有机助磨剂用量在0.50%时流动度最好,无机助磨剂用量在0.10%时流动度最好。     

EFFECTS OF GRINDING AIDS VIBRATION MILLING OF ALUMINUM

Fine aluminum powder is widely used in making paints, printing inks, slurry explosives, pyrotechnic chemicals etc. Hence the production of aluminum powder is highly important. In this paper the effect of grinding aids on the grinding characteristics of aluminum in a vibration mill under an inert atmosphere of nitrogen has been investigated. It is found that the use of grinding aids is essential in grinding of atomized aluminum. Among four different grinding aids, stearic acid appears to be the best grinding aid.     

Analysis of grinding aid performance effects on dry fine milling of calcite

The control mechanism in the production of fine particles is important in dry grinding processes, which are popular in the grinding of some minerals. The behavior of the fine particles with each other and with the mill environment is complex and needs to be investigated in detail (on a micro-scale) in every application. One of the parameters controlling the fine particles in a mill is the use of the correct amount and type of grinding aid. Mechanisms of action must be understood well to develop grinding aids and fully utilize their positive effects. As a general explanation, with the use of grinding aids, the production tonnage can be increased at the desired product fineness, as well as achieving a finer product at the same production tonnage. However, it is necessary to know other mechanisms and effects to increase efficiency and correct use. The influence of grinding aids on the dry fine grinding of calcite using several analysis methods was revealed in the present study. Within the context, the results were assessed considering grinding performance (particle size distribution and size reduction ratio), product quality (color properties), flowability, adsorption properties (FTIR), and agglomeration behavior (SEM). Moreover, the tested effect of each grinding aid was discussed for each analysis, and the collected results were combined around a summary core diagram.     

A mechanism of diamond-abrasive finishing of monocrystalline silicon carbide

The investigation of the mechanism of diamond-abrasive finishing of monocrystalline silicon carbide on the basis of a generalized model of formation and removal of debris particles and material removal has demonstrated that the use of specific value of the energy of transfer as a criterion for the assessment of machining efficiency permits substantiating suitability of boron carbide and titanium dioxide powders for fine grinding and of chromium oxide, alumina, ceric oxide, and ASM 2/1 diamond micron powders for ultrafine grinding.     

Effect of grinding aids on the kinetics of fine grinding energy consumed of calcite powders by a stirred ball mill

An experimental investigation was carried out on the ultra-fine grinding of inorganic powders using a stirred ball mill. The power consumed in the grinding process was measured, and the comminution coefficient, K, in the grinding kinetics equation was examined, based on an analysis of the relationship between the experimental specific surface area and the particle-size distribution of ground products. The effect of grinding aids on the comminution coefficient, K, was also investigated. It was demonstrated that the grinding rate for calcite could be improved by the addition of grinding aids. When using grinding aids, K improved by 16.0% and 34.2% for 60 wt% and 70 wt% slurry concentrations, respectively. Thus grinding aids are very effective in the submicron range grinding process.     

Impact of grinding aids on dry grinding performance,bulk properties and surface energy

In dry fine grinding processes the relevance of particle-particle interactions rises with increasing product fineness. These particle-particle interactions reduce the grinding efficiency and complicate the process control. The adsorption of grinding aid molecules on the product particle surface is a common measure to handle these effects. To ensure an efficient grinding aid application, the impacts of additives on particle and bulk properties, which influence the micro-processes inside the mill, need to be understood. Within this study the effects of several grinding aids on dry fine grinding of limestone in a laboratory vibration mill were investigated. Unlike in many other scientific works, the impacts of grinding aids were analyzed on different levels simultaneously: Grinding success and agglomerate size distributions were evaluated by wet and dry particle size measurements, respectively. Additionally, material coating on the grinding media, powder flowabilities and particle specific surface energies were measured. It was shown that all of the investigated grinding aids influence the grinding efficiency. However, the formation of agglomerates is not necessarily linked to the product fineness. Furthermore, a strong impact of certain grinding aids on the flowability of the product powder was determined. Thereby, the bulk flow behavior also determines the grinding result as it affects the stress mechanism inside the mill. Moreover, a direct relation between surface energy and powder flowability as well as agglomeration behavior could be demonstrated.     

溶胶-凝胶生物活性玻璃超细粉体的制备与生物矿化性能研究

通过溶胶-凝胶和湿法研磨工艺制备了粒径分布在1μm以下的生物活性玻璃超细粉体. 采用XRD、FTIR、SEM测试方法对研磨前后粉体在模拟生理溶液(SBF)中的生物矿化性能进行了对比分析与表征, 结果表明: 在SBF中两种粉体表面都生成了碳酸羟基磷灰石(HCA), 并且经湿法研磨后的溶胶-凝胶生物活性玻璃超细粉体的生物矿化速度显著提高. 通过对不同浸泡时间SBF溶液的pH值测定可知, 在同样反应时间情况下, 超细粉体浸泡液的pH值低于研磨前颗粒. 浸泡液的ICP测试也表明研磨前后玻璃样品的离子溶出规律有所不同.