污泥化学链燃烧过程中氮迁移转化特性研究

在单流化床反应器上探究了污泥化学链燃烧过程中氮迁移转化特性。由于赤铁矿载氧体反应活性低,采用30%水泥对其改性。结果表明,水泥改性可提高污泥热解气化反应速率以及赤铁矿还原反应速率,进而提高污泥碳转化率,但是NO生成率也增加。随着反应温度的升高,污泥的碳转化率和NO生成率均增加。另外,随着水蒸气浓度的增加,碳转化率增加,同时可降低NO生成。在污泥化学链燃烧过程中,NO生成率为0.286%-0.768%,低于污泥空气焚烧氮氧化物排放量。     

寡养单胞属菌株USTB-2对赤铁矿的捕收效果及机理

对从司家营铁矿场土壤中筛选出来的非致病性寡养单胞属菌株USTB-2作为赤铁矿的捕收剂进行了研究.Zeta电位测试知该菌在较大pH范围内带负电.经菌体USTB-2作用后，赤铁矿接触角增加了3395°，表面疏水性得到了极大的提高.在pH为6，菌体添加量为60g/t时，赤铁矿浮选回收率可达到7631%.机理研究表明，菌体USTB-2表面具有的烃类物质、羧基、磷酸基团使其具有类似脂肪酸类捕收剂的特性，通过“桥联”作用促进赤铁矿颗粒之间形成絮团；这证实寡养单胞属细菌USTB-2可以充当赤铁矿捕收剂.     

Application of the Brownian dynamics method to a rod-like hematite particle dispersion

We have investigated various problems that arise in applying the Brownian dynamics method to a suspension composed of rod-like hematite particles, which have a magnetic moment normal to the particle axis direction. The accuracy and the deviation of simulation results from theoretical solutions have been discussed by comparison with the theoretical solutions that were obtained by solving the basic equations of the orientational distribution function. The characteristics of the negative viscosity are not observed to be dependent on a time interval unless a sufficiently short time interval is used. The present simulation results can satisfactorily reproduce the qualitative characteristics of the negative magneto-rheological effect that was predicted by the previous theoretical investigation. Good quantitative agreement is obtained in the range of small-applied magnetic fields, but agreement is not significantly good in the large magnetic field region. The deviation of the negative viscosity from the theoretical prediction cannot be improved by using a more accurate numerical algorithm such as moving from Euler to second-order or fourth-order Runge–Kutta. The results of the orientational distribution can well reproduce the characteristic features that the distribution has a gradual shape with low linear-like peak, which is in significant contrast to the sharp single-peak distribution of a ferromagnetic rod-like particle dispersion. The present orientational distributions are in significantly good agreement with those of the theoretical prediction in regard to the position and the height of a peak and the general shape of the overall profile. Good agreement of the present magnetisation curves with the theoretical prediction verifies that the spin rotational Brownian motion is activated at a physically reasonable level in the present simulations.     

Hematite/Polystyrene Raspberry-Like Microcomposites as Stable Support for Silver Nanoparticle Immobilization

Among the methods utilized for the preparation of raspberry-like microcomposites, due to its simplicity and universality, the electrostatically-driven deposition of nanoparticles at the surface of microparticles is especially attractive. This process, leading to the formation of a single nanoparticle monolayer, is widely reported. On the other hand, no data concerning the electrostatically-driven formation of nanoparticle bilayers at the surface of microparticles are reported. To fill this gap, the detailed investigation of the formation of silver/hematite nanoparticle bilayers at the surface of polystyrene microparticles is reported. First, the hematite/polystyrene raspberry-like microcomposites are obtained by immobilization of hematite nanoparticles under an electrostatically-driven process. The stability of hematite/polystyrene microcomposites at elevated temperatures up to 323 K is monitored using microelectrophoresis. No significant changes in the hematite nanoparticle layer coverage are observed after prolonged time of incubation. This proves the irreversible character of nanoparticle immobilization. Next, the hematite/polystyrene microcomposites are utilized as the interfaces for immobilization of negatively charged silver nanoparticles. This process is quantitatively described using electrokinetic measurements. The changes in the hydrodynamic diameter of microcomposites are also determined. Finally, the validity of the electrokinetic model used in this work for predicting the zeta potential of the silver/hematite/polystyrene microcomposites is confirmed.     

聚氧化乙烯絮凝微细粒高岭石强化赤铁矿反浮选脱硅机理研究

通过矿物浮选试验并结合激光粒度测试、扫描电镜(SEM)、矿物Zeta电位及XPS等检测方法对赤铁矿反浮选过程中聚氧化乙烯絮凝细粒高岭石的行为及机理进行了研究.矿物絮凝浮选试验表明：添加聚氧化乙烯可以提高高岭石的单矿物回收率和人工混合矿分离效率,促进赤铁矿和高岭石反浮选分离.激光粒度测试和扫描电镜检测结果表明：聚氧化乙烯不絮凝赤铁矿,但絮凝高岭石颗粒,使其表观粒径增大.Zeta电位测试和XPS分析表明：聚氧化乙烯在高岭石颗粒表面发生化学吸附,并使其Zeta电位正移.因此,开展聚氧化乙烯对硅酸盐矿物絮凝的研究对赤铁矿和高岭石反浮选分离具有意义.     

Surface areas of kaolin, α-Fe2O3 and hydroxy-Al montmorillonite

 Adsorption of eight organic molecules on kaolin, α-Fe₂O₃ and hydroxy-Al montmorillonite was studied to examine the effect of sorbate area on the values of the surface area of these materials. For each sorbent, the number of molecules at monolayer coverage per gram produced a single hyperbola when plotted as a function of the area occupied by an adsorbate. The equations of the hyperbolas are: NA=22.23 A ^0.098 for the kaolin, NA=53.70 A ^-0.399 for α-Fe₂O₃ and NA=161.81 A ^0.322 for the hydroxy-Al montmorillonite. These equations give accessible surface areas and not the true surface areas of the solids studied, which remain elusive. Received: 13 November 1997 Accepted: 24 January 1998     

Possibility of using strain F9（Serratia marcescens） as a bio-collector for hematite flotation

In this study, we characterized strain F9 and evaluated the interaction between strain F9 and hematite by scanning electron microscopy（SEM）, Fourier transform infrared spectrophotometry（FTIR）, zeta potential, flotation, and other methods. The results showed that strain F9 belongs to Serratia marcescens. This brevibacterium had CH2, CH3, and hydroxyl groups on its cell wall, which imparted a strong hydrophobic and negative charge. Adsorption of strain F9 reduced the zeta potential of the hematite surface and increased the hydrophobicity of the hematite surface, thereby generating hydrophobic hematite agglomerates. At least four groups on strain F9 interacted with the hematite surface, which contributed to chemical interactions of carboxylic groups and hydrophobic association among hydrophobic hematite particles. The possible use of strain F9 as a bio-collector for hematite flotation was proved.     

川西北汉旺地区卡尼期鲕粒灰岩特征及地质意义

探讨川西北地区晚三叠世卡尼期马鞍塘组下部的鲕粒灰岩的沉积相及沉积时的古气候、古盐度。在前人研究成果基础上,对绵竹县汉旺观音崖剖面开展野外调查和室内薄片鉴定及碳氧同位素测试,结果表明共发育3套鲕粒灰岩,主要沉积于碳酸盐缓坡,由下到上鲕粒以复鲕、同心鲕、放射同心鲕、脑状鲕呈现,展示鲕粒沉积时海水能量降低、水体逐渐加深的趋势;上部灰岩中脑状鲕与同心鲕共存且同心鲕具双峰态粒度分布,显示鲕粒沉积时受到风暴作用影响。碳、氧同位素测试显示,鲕粒灰岩沉积时的古温度大体在24～35℃,Z 值在127～131,表明在卡尼期早期,川西北地区以蒸发量较高的低纬度地区干热气候为主。     

Mechanism of the formation of micropores in the thermal decomposition of goethite to hematite

The mechanisms of the formation of micropores in the thermal decomposition of goethite to hematite have been studied through the measurements of X‐ray diffraction, Brunauer–Emmett–Teller adsorption and scanning electronic microscopy, as well as the estimation of crystal cell parameters in this work. The results have shown that the thermal decomposition led to the crystal cells of goethite to be contracted along the [010] and [001] directions and to be elongated along the [100] direction, forming nano‐scale and rod‐like hematite. It was the contractions along the two directions that led to the formation of the micropores in the hematite particles. Copyright © 2015 John Wiley & Sons, Ltd.     

基于赤铁矿的生物质化学链燃烧过程中氮氧化物的释放特性

在单批次进料固定床上,基于赤铁矿载氧体,研究了还原反应阶段反应温度和水蒸气量对谷壳的氮氧化物释放特性的影响。研究表明,碳转化率随反应温度升高而增加,但随水蒸气量呈先增加后下降,并在水蒸气量为1.0 g/min时达到最大值。在实验条件下,还原阶段未检测到NO₂。随着反应温度由750 ℃升高到900 ℃,NO的生成率增加,而N₂O的生成率先增加后降低,在850 ℃时达到最大值。水蒸气量由0.5 g/min升高到2.0 g/min,N₂O和NO的生成率均增加,且NO增加速率高于N₂O。在反应后的载氧体中,检测到KAlSi₃O₈存在,表明载氧体与生物质中的K元素发生反应。