无机粉体改性效果对比表面积的影响

分别利用钛酸酯偶联剂(NDZ-311)、磷酸酯偶联剂(FX-1)、铝酸酯偶联剂(L-2)和硅烷偶联剂(KH-560)对滑石粉(Talc)进行表面改性,并利用力学性能与比表面积(BET)等测试方法研究了改性Talc对PP复合体系性能的影响,发现BET极大值点与力学性能极大值点呈对应关系,因此可利用比表面积测定来定性或定量地反映偶联剂对无机粉体的改性效果。SEM结果表明:改性后Talc在基体中的分散度得到提高,并能更好地与基体结合。     

不同比表面积球磨渣粉对水泥性能的影响

借助粒度分布仪,分析了球磨矿渣在不同比表面积情况下的粒度分布,研究结果表明:随着比表面积的增大,球磨矿渣粉的细颗粒明显增多,n值增大,即随着比表面积的增加,粒度分布越来越宽.研究同时指出:矿渣粉比表面积的变化对矿渣水泥的标准稠度用水量影响不大;比表面积的增加,有利于提高矿渣水泥的强度,但对其流变性的影响没有特定的规律.     

Thermal reactivity of ammonium perchlorate crystallised from solutions having different pH

The thermal reactivity of ammonium perchlorate was found to be dependent on the pH of the solution from which it had been crystallised. A nitric acid-crystallised sample reacted faster than an ammonium hydroxide-crystallised one.     

氧化铝超细粉体填料表面改性的研究

研究了表面改性剂配比、用量、改性时间等对氧化铝超细粉体填料表面改性效果的影响,并浅析了改性机理。     

Specific features of thermal decomposition of ammonium perchlorate subjected to γ radiation

Results of studying thermal decomposition of ammonium perchlorate (AP) samples in the original form and after irradiation by γ-quanta of ⁶⁰Co by methods of differential scanning calorimetry and dynamic thermogravimetry with heating rates b = 0.1–0.3 K/sec are described. Irradiation is performed in air at a temperature of 298 ± 2 K and a dose rate of ≈0.2 Gy/sec in the range of absorbed doses D = 0–150 kGy. Preliminary irradiation is demonstrated to lead to substantial transformations of the pattern of thermal decomposition of ammonium perchlorate in the dynamic regime of heating: the single-stage process of decomposition of non-irradiated samples proceeding at b = 0.107 K/sec in the temperature range of 625 to 743 K is replaced by a multistage process. At D = 150 kGy, exothermal transformations accompanied by noticeable losses of sample mass are observed starting from 473 K. Within experimental errors, the total thermal effect of AP decomposition is found to be independent of the absorbed dose and amounts to −1150 kJ/kg on the average. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 6, pp. 69–74, November–December, 2007.     

铝型材表面粉末静电喷涂生产工艺

介绍了粉末涂料静电喷涂的工艺原理及其在铝型材表面的应用。     

筛分法测定高氯酸铵粒度的影响因素

通过试验认定筛分法测定高氯酸铵粒度的影响因素不仅包括颗粒的形状和颗粒在筛面上的角度、筛分方法、筛分时间等固定因素,还包括标准筛的筛孔孔径偏差以及环境因素,其中环境因素包括环境温湿度和静电等。可以通过空调或除湿机来调节环境温湿度,可以通过增加空气湿度来减少静电积聚。     

TRMS45.3辊磨生产高比表面积矿渣粉的实践

矿渣的资源化利用是目前冶金渣废弃物资源化率最高的一种材料,矿渣作为建材产品使用具有很多的优势。由中材装备集团有限公司最新研发的生产矿渣超细粉(≥520m~2/kg)的TRMS45.3矿渣辊磨系统,目前已投产运转3个多月,生产矿粉16万吨,从磨机生产情况来看,在成品比表面积520~530m~2/kg时可实现产量90~97t/h、主电机电耗37~38k Wh/t,达到或超过了设计指标。     

Influence of gas composition on the reactivity of cokes

The NSC reactivity test is often criticised for not being able to accurately predict the performance of cokes in the blast furnace. One explanation proposed for this inaccuracy is that the gas used in the NSC test, pure carbon dioxide, is different to the gas that coke is exposed to in blast furnaces, which is a complex mixture including carbon monoxide, carbon dioxide and nitrogen. The aim of this work was to see to what extent different cokes behaved differently during the NSC test under different gases.Nine Australian coals, used in coking blends, were selected to cover a wide range of rank, maceral composition and elemental composition of the mineral matter. These coals were coked and their relative reactivities in a series of gas mixtures were compared. The time for the reaction of the coke in a 30% CO₂/70% CO mixture was set to eight hours to give about the same weight loss as two hours exposure to 100% CO₂.The main conclusion of this study was that gas composition (using mixtures of CO, CO₂ and N₂) had little effect on the relative rate of gasification of cokes over a wide compositional range of gas and of coke (although of course the absolute reaction rate decreased with decreasing CO₂ levels). The previous studies that suggested changes in gas composition affect the relative reaction rate of different cokes were misleading because they performed the studies at constant burnoff time (2 h) rather than ensuring the cokes were reacted to about the same weight loss.Thus any differences between the behaviour of cokes in the NSC test and in the blast furnace are not due to differences in gas composition between the two.The CSR value was found to be a combination of strength and reactivity: for the data in this study, CSR was determined by a two-component fit involving CRI and the I600/10 index (the strength of the unreacted coke as measured by the CSR tumble test).     

超细粉体填料表面化学修饰

研究了表面改性剂组成、用量、改性时间等对氢氧化铝超细粉体填料表面化学修饰效果的影响,并浅析了改性机理。     

Anomalies in the burning of ammonium perchlorate and ammonium nitrate

Conclusions We have considered possible mechanisms of retardation of the chemical reactions when ammonium nitrate and perchlorate burn and have shown that one such mechanism is retardation by the water formed during combustion.We have studied the effect of the additives silica, liquid silicone, calcium stearate, etc. on the burning of ammonium perchlorate and ammonium nitrate catalyzed with chromium oxide in order to establish the causes of the anomalies observed during their combustion.We have shown that over a certain pressure range adding silica eliminates the observed anomalies (fall in burning rate with increase in pressure and pulsating combustion), whereas the addition of calcium stearate intensifies them.Depending on the pressure interval and the conditions under which combustion proceeds, the same additive may play the role of an inert admixture, a catalyst, or an inhibitor, which is apparently associated with changes in the leading reactions in differentpressure intervals.The author warmly thanks V. K. Bobolev for his assistance.Fizika Goreniya i Vzryva, Vol. 4, No. 3, pp. 314–322, 1968     

高氯酸铵含量对高铝富燃料推进剂中重要组分高氯酸铵/铝 一次燃烧性能和铝粉团聚的影响

采用CO2激光点火装置联合高速摄影系统及扫描电子显微镜等凝聚相燃烧产物分析技术,研究了高氯酸铵(AP)含量对高Al富燃料推进剂中重要组分AP/Al一次燃烧过程中燃烧现象、引燃时间、燃烧扩散时间、燃尽时间、燃烧效率、颗粒团聚及凝聚相燃烧产物的表面形貌、粒径及其分布的影响。结果表明,各AP/Al混合粉体的燃烧过程均可分为表面引燃、燃烧扩散和火焰熄灭3个阶段,但各样品在不同燃烧阶段的燃烧现象存在明显差异。AP含量由10wt%增至30wt%,样品燃烧剧烈程度增强,燃烧过程中固相颗粒的溅射现象越加明显;在火焰熄灭阶段,各样品燃烧由以停留在样品燃面处的燃烧为主逐渐变为以溅射颗粒的燃烧为主,且随反应进行,燃面已燃固相颗粒最先熄灭,各样品表面引燃时间、燃烧扩散时间、燃烧持续时间均缩短,即燃烧反应速率逐渐加快。在AP/Al混合物中,铝粉的燃烧效率、凝聚相燃烧产物粒度及其团聚程度随AP含量增加而增加。     

Effect of pretreatment on the sublimation of ammonium perchlorate

The effects of pretreatments on the sublimation of pure ammonium perchlorate (AP) were studied by differential thermal analysis. The addition of inorganic salts (doping), or preheating, lead to desensitisation of the sublimation process, whereas it was sensitised by precompression. Sublimation increased with decrease in the particle size of the AP from 500 to 200 microns, but decreased with a further decrease in size from 200 to 100 microns. The results are interpreted in terms of gross imperfections and strain in the AP crystals.     

Sintering Kinetics at Isothermal Shrinkage: Effect of Specific Surface Area on the Initial Sintering Stage of Fine Zirconia Powder

The isothermal shrinkage behaviors of fine zirconia powders (containing 2.8–2.9 mol% Y₂O₃) with specific surface areas of about 6 and 16 m²/g were investigated to clarify the effect of specific surface area on the initial sintering stage. The shrinkage of powder compact was measured under constant temperatures in the range of 1000°–1100°C. The increase in specific surface area enhanced the densification rate with increasing temperature. The values of activation energy ( Q ) and frequency-factor term (β₀) of diffusion at initial sintering were estimated by applying the sintering-rate equation to the isothermal shrinkage data. The Q of diffusion changes little but the β₀ increases with the increase in specific surface area. It is therefore concluded that the increase in the specific surface area of fine zirconia powder enhances the shrinkage rate because of an increase in the β₀ at the initial stage of sintering.     

松木粉制备高比表面积炭基固体酸催化剂

以一种廉价的农林废弃物——松木粉为原料,首先经过炭化和活化处理,制备活性炭,再通过苯磺酸重氮盐还原法处理活性炭引入磺酸基团(—SO₃H),从而制备出具有高比表面积的炭基固体酸催化剂(AC-SO₃H)。其比表面积达到 1364 m²/g,磺酸基密度为 1.36 mmol/g。以乙酸的酯化反应考察了炭基固体酸催化剂的催化活性,并与Amberlyst-15、Nafion NR50以及Nafion SAC-13等几种固体酸催化剂进行了比较。实验结果表明,炭基固体酸催化剂的催化活性仅略低于Amberlyst-15,高于Nafion NR50和Nafion SAC-13,炭基固体酸催化剂的成本也远远低于Nafion NR50和Nafion SAC-13。研究结果表明,以松木粉为原料,通过炭化、活化和磺化处理能够得到性能优异且成本低廉的炭基固体酸催化剂。