磁选技术在水污染治理中的应用

磁分选技术因其操作简单、分选能力强、应用范围广、不产生二次污染等特点,在污水净化、水资源循环利用等领域的应用日益增多。本文综述了近年来国内外磁选技术在水污染治理中的应用研究进展;同时对水治理磁分离新技术--超导磁选、磁泳分离、磁种-絮凝磁选、磁场辅助膜分离等作了介绍,并探讨了磁选技术的发展方向。     

聚羧酸高效减水剂对分选和磨细粉煤灰作用差异研究

为揭示聚羧酸高效减水剂对分选和磨细粉煤灰的作用效果差异,采用净浆流动度法和吸光度法,研究了聚羧酸高效减水剂对两种粉煤灰浆体流动度的影响差异,以及在其表面吸附特征的差异.结果表明,在水灰比为0.4时,磨细粉煤灰浆体没有流动性,而分选粉煤灰净浆流动度为98 mm;但掺入聚羧酸高效减水剂后,磨细粉煤灰浆体的流动性明显高于分选粉煤灰;聚羧酸高效减水剂在两种粉煤灰颗粒表面的吸附均符合Langmuir等温吸附方程,且磨细粉煤灰颗粒表面的吸附量远大于分选粉煤灰.     

流化床内介质主要流化特性参数的研究

利用6种不同粒度的磁铁矿粉作为加重质研究流化床的流化特性。研究表明,随着颗粒平均粒径的减小,床层表面的气泡尺寸明显减小,适宜分选的气速可调范围变宽,有利于流化床分选的进行,为确定最佳的分选条件提供了依据。     

我国高梯度超导磁分离装备在非金属矿选矿中的应用

介绍了国内磁选设备的研究现状,对目前国内高梯度超导磁分离装备的结构原理、分选方式以及选矿特性进行了分析,并通过大量磁选试验验证了高梯度超导磁分离装备在我国非金属矿选矿领域中高效、节能等方面的优势,建议大力发展节能、高效磁选技术。     

新型氨基化磁性纳米粒子的合成

通过嫁接方法在包有二氧化硅的纳米CoFe2O4磁粒表面进行氨基化修饰,制备出一种可用于生物医学领域的新型氨基化纳米磁粒,采用TGA-DTA,IR,VSM和Zeta-potential等测定方法,对氨基化和未氨基化的CoFe2O4纳米粒子进行了表征。元素分析结果显示,有0.98 mmol/g的有机分子固定在纳米粒子表面;红外和热分析数据显示,带氨基的有机分子嫁接到磁粒表面的二氧化硅壳层上;Zeta电位数据也显示,带氨基的有机分子嫁接到纳米磁粒表面;样品的磁性参数显示,氨基化纳米磁粒仍具有好的磁学性能。     

磁粉表面密实化处理对磁粉性能的影响

多年来,在磁浆制备工艺中,寻求一种既能使磁粉在磁浆中快而均匀地分散,又不致于损伤磁粉晶形的有效方法,一直是磁浆研究工作者所关心和不断探讨的问题。磁粉的表面性能如何是影响磁粉在磁浆中分散性的重要因素,它直接影响磁记录介质的特性。为了改善磁粉的表面性能,要对磁粉进行表面处理,其方法很多,以前已经有过一些报道。本文主要论述表面和密实化处理对磁粉性能的影响。     

表面改性磁种-磁滤技术处理含油废水的研究

将表面改性后的磁粉,磁性颗粒分别作为磁种和磁滤材料,以出水含油量、除油率为试验指标,采用磁种-磁滤技术处理江苏油田废水.试验结果表明,经改性后的Fe3O4磁种粒度小、比表面积大,与油滴的吸附亲和力增强,且包覆在Fe3O4表面的偶联剂能阻止Fe3O4微粒聚结,减缓沉降速度,从而提高除油效果.当进水含油量为140.3mg/L,磁种投加量300mg/L、搅拌强度250r/min,搅拌时间20min、磁滤速度25m/h、磁感应强度0.0839T时,出水含油量降为19.8mg/L,除油率迭85.9%.     

煤的高梯度磁场脱硫的基础研究

本文阐述了高梯度磁场分选(HGMS)的理论基础;着重分析了煤系矿物磁性质的研究结果和我国高硫煤进行高梯度磁场脱硫的工艺可行性,并在此基础上讨论实现煤的高梯度磁场脱硫的技术途径。     

重介质旋流器选煤的分选工艺探讨

煤炭质量的下降和产品要求的提升加大了对于煤炭分选环节的要求,重介质旋流器分选工艺作为一种选别精度高的方法在煤炭行业应用广泛。介绍了2种常见的重介质旋流器分选工艺,并结合其延伸配套工艺对2种分选方法进行分析比较。     

选煤新技术在盘江矿区的应用

盘江矿区各选煤厂近年来陆续使用了先进的重介质旋流器分选技术、X系列跳汰机分选新技术以及浮选矿浆准备(即煤泥表面改质)、煤泥高效脱水、干法选煤、浮选尾煤干燥等新技术新工艺、新设备,取得了较好的经济效益和环保效益。     

高速钢刀具固体润滑涂层的研究

为了解决高速钢刀具磨损快的问题,延长刀具使用寿命,通过研究磷化处理加固体润滑涂层的工艺方法,在刀具表面制备出了以wS2为主的固体润滑涂层.实验证明:在外加磁场(3.0×10-3T)作用下,刀具表面磷化膜的粗糙度得到较好的控制;此时进行固体润滑剂涂覆刀具处理,涂层厚度达4.935 μm,刀具使用寿命最高,比未进行处理的刀...     

Effect of weathering on oil sands processability

Effect of weathering on oil sand processability was studied using a good processing ore, a laboratory weathered ore and a naturally weathered ore. The laboratory weathered ore was prepared by weathering the good processing ore in an oven under controlled conditions to study the nature of ore weathering. It was found that the bitumen recovery, bitumen flotation rate, and bitumen froth quality were greatly reduced due to ore weathering. It was also observed that the fresh bitumen coating on a silicon surface could recede and liberate from the silicon surface easily even in a warm water of 35°C. However, after weathering of the bitumen coating, its liberation became more difficult and effective liberation of bitumen from the silicon surface could only occur at higher temperature of 65°C. The current study further confirms that weathering enhanced adhesion of bitumen with solids, causing difficulties for bitumen liberation from sand grains and hence poor processability of weathered ores.     

Corrosion stability of polyester coatings on steel pretreated with different iron–phosphate coatings

The influence of steel surface pretreatment with different types of iron–phosphate coatings on the corrosion stability and adhesion characteristics of polyester coatings on steel was investigated. The phosphate coating was chemically deposited either from the simple novel plating bath, or with the addition of NaNO₂, as an accelerator in the plating bath. The morphology of phosphate coatings was investigated using atomic force microscopy (AFM). The corrosion stability of polyester coatings on steel pretreated by iron–phosphate coatings was investigated by electrochemical impedance spectroscopy (EIS) in 3% NaCl solution, while “dry” and “wet” adhesion were measured by a direct pull-off standardized procedure. It was shown that greater values of pore resistance, R_p, and smaller values of coating capacitance of polyester coating, C_c, on steel pretreated with iron–phosphate coating were obtained, as compared to polyester coating on steel phosphated with accelerator, and on the bare steel. The surface roughness of phosphate coating deposited on steel from the bath without accelerator is favorable in forming stronger bonds with polyester coating. Namely, the dry and wet adhesion measurements are in accordance with EIS measurements in 3% NaCl solution, i.e. lower adhesion values were obtained for polyester coating on steel phosphated with accelerator and on the bare steel, while the iron–phosphate pretreatment from the novel bath enhanced the adhesion of polyester coating on steel.     

硫酸脲分解磷矿反应动力学

通过硫酸脲分解磷矿的搅拌强度和磷矿粒度实验，探讨其中的传递过程。实验研究表明，硫酸脲分解磷矿为典型的缩芯反应，反应过程受产物形成的固膜扩散所控制，在排除液相扩散和反应粒子表面及微孔影响下，进行反应动力学实验。建立了硫酸脲与磷矿反应的动力学模型，由实验数据求得动力学参数，其反应活化能为12．73kJ／mol。     

Evaluation of pre-treatment processes for HRS (hot rolled steel) in powder coating

Hot rolled steel (HRS) is used extensively in the automotive, agricultural and appliance industries. The corrosive response of HRS was investigated after it had been exposed to various surface treatments, prior to powder coating. The behaviour of three conversion coatings: zinc phosphate (ZnP), iron phosphate (FeP) and zirconium (Zr)-based nano-scaled, on HRS was studied. HRS is naturally covered with iron oxide scale and this was removed from the surface by mechanical and chemical processes, prior to the application of surface treatment and organic coatings. The following tests on differently treated panels were conducted to evaluate corrosion performance: adhesion tests such as, crosshatch, pull-off, and conical bending, SEM, XPS, salt spray and electro-chemical impedance studies were also performed. Good correlations were recorded showing that zinc phosphate conversion coating gave the best performance, and zirconium-based nano-structured conversion coating, was superior to that of iron phosphate conversion coatings on HRS.     

Effect of vanadium additive and phosphating time on anticorrosion,morphology and surface properties of ambient temperature zinc phosphate conversion coatings on mild steel

An attempt has been made to investigate the effect of phosphating time and vanadium additive on the anticorrosion and surface properties of ambient temperature zinc phosphate coatings. Zinc phosphate coatings with different phosphating times and vanadium concentrations were applied to low carbon steel samples. A potentiostatic polarization test in 3.5 wt% NaCl solution was carried out to investigate the electrochemical properties of coated samples. Field emission scanning electron microscopy, energy-dispersive spectroscopy, and atomic force microscopy were utilized to evaluate the microstructure, chemistry and roughness of coatings. Surface properties such as wettability, surface tension, and work of adhesion were measured. Results indicate that the sample which was immersed for 30 min in the phosphating bath exhibits the lowest corrosion current density, one tenth of bare steel, due to formation of a compact coating while having a low number of microcracks. Addition of 500 ppm vanadium to the coating in a secondary bath decreases the corrosion rate of zinc phosphate coating remarkably, by almost 80%. Microstructural results reveal that vanadium-rich precipitates are formed and enhance the coating coverage on the steel substrate. Vanadium addition increases the surface roughness, surface free energy, and work of adhesion of the phosphate coating.     

磷酸铝包覆氧化铁黄颜料的制备及其耐温性能研究

氧化铁黄颜料受热易脱水变色,限制了其在温度较高环境下的应用。提高氧化铁黄的热稳定性具有很重要的意义。通过液相水解沉积的方法对氧化铁黄表面进行磷酸铝表面包覆,研究了磷酸铝包膜的工艺条件（pH、包膜量、温度）对氧化铁黄包覆的表面形貌和微观结构的影响。结果表明：在pH为7、磷酸铝的包膜量为13%、包覆温度为65 ℃时,在氧化铁黄表面的包覆效果最佳。采用色差法研究了在最佳条件下进行磷酸铝包覆的氧化铁黄颜料,结果表明其耐温性得到显著提高。     

Formation of Apatite Coatings on an Artificial Ligament Using a Plasma- and Precursor-Assisted Biomimetic Process

A plasma- and precursor-assisted biomimetic process utilizing plasma and alternate dipping treatments was applied to a Leed-Keio artificial ligament to produce a thin coating of apatite in a supersaturated calcium phosphate solution. Following plasma surface modification, the specimen was alternately dipped in calcium and phosphate ion solutions three times (alternate dipping treatment) to create a precoating containing amorphous calcium phosphate (ACP) which is an apatite precursor. To grow an apatite layer on the ACP precoating, the ACP-precoated specimen was immersed for 24 h in a simulated body fluid with ion concentrations approximately equal to those in human blood plasma. The plasma surface modification was necessary to create an adequate apatite coating and to improve the coating adhesion depending on the plasma power density. The apatite coating prepared using the optimized conditions formed a thin-film that covered the entire surface of the artificial ligament. The resulting apatite-coated artificial ligament should exhibit improved osseointegration within the bone tunnel and possesses great potential for use in ligament reconstructions.     

Effect of copper (II) acetate pretreatment on zinc phosphate coating morphology and corrosion resistance

Zinc phosphate coating is widely used for corrosion protection of metallic materials, mainly mild steel. In the present study, the effect of pretreatment with copper acetate solution on zinc phosphate layer properties was investigated via scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The corrosion resistance of the coating was evaluated using polarization curves and electrochemical impedance spectroscopy in an aerated 3.5% NaCl solution. The pretreatment resulted in a compact and uniform phosphate coating with smaller crystal size and greater surface coverage. Electrochemical results showed better corrosion resistance for the pretreated phosphate layer compared with the untreated one.     

Optimization of phosphate coating properties on steel sheet for superior paint performance

The adhesion of electrodeposition (ED) paint on steel sheets for automobiles is highly influenced by the properties of the zinc phosphate coating which is used to improve its corrosion resistance. In the present study, a steel surface was pretreated with two types of zinc phosphate formulations followed by ED painting. The surface morphology, crystal plane, and porosity properties of phosphate coating on steel samples were studied by scanning electron microscope, X-ray diffraction, and electron probe microanalyzer, respectively. The corrosion resistance of painted samples was evaluated by an accelerated corrosion test as well as by electrochemical techniques like cathodic disbonding and AC?CDC?CAC tests. The phosphate coating enriched with a phosphophyllite structure showed small globular crystals with less porosity, whereas a hopeite structure showed coarse crystals with high porosity and comparatively thicker coating. The maximum corrosion resistance was observed in the painted sample, where the phosphate coating comprised a phosphophyllite structure. On the other hand, the painted samples phosphated with a predominantly hopeite structure showed inferior corrosion resistance performance. The unphosphated sample showed severe degradation in paint adhesion and corrosion resistance, which substantiates the importance of phosphate pretreatment.