具有良好可再生性的新型二氧化硅磁性氧化石墨烯纳米复合材料

Graphene oxide (GO) wrapped Fe₃O₄ nanoparticles (NPs) were prepared by coating the Fe₃O₄ NPs with a SiO₂ layer, and then modifying by amino groups, which interact with the GO nanosheets to form covalent bonding. The SiO₂ coating layer plays a key role in integrating the magnetic nanoparticles with the GO nanosheets. The effect of the amount of SiO₂ on the morphology, structure, adsorption, and regenerability of the composites was studied in detail. An appropriate SiO₂ layer can effectively induce the GO nanosheets to completely wrap the Fe₃O₄ NPs, forming a core-shell Fe₃O₄@SiO₂@GO composite where Fe₃O₄@SiO₂ NPs are firmly encapsulated by GO nanosheets. The optimized Fe₃O₄@SiO₂@GO sample exhibits a high saturated adsorption capacity of 253 mg·g?1 Pb(II) cations from wastewater, and the adsorption process is well fitted by Langmuir adsorption model. Notably, the composite displays excellent regeneration, maintaining a ~90% adsorption capacity for five cycles, while other samples decrease their adsorption capacity rapidly. This work provides a theoretical guidance to improve the regeneration of the GO-based adsorbents.     

微波预处理对复杂铜矿磨矿及浮选动力学的影响

The effect of CaCO₃, Na₂CO₃, and CaF₂ on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe₃PO₇ and apatite was investigated. The results revealed that Na₂CO₃ had the most significant effect on iron recovery and dephosphorization, followed by CaCO₃, the effect of CaF₂ was negligible. The mechanisms of CaCO₃, Na₂CO₃, and CaF₂ were investigated using X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectrometry (SEM–EDS). Without additives, Fe₃PO₇ was reduced to elemental phosphorus and formed an iron–phosphorus alloy with metallic iron. The addition of CaCO₃ reacted with Fe₃PO₇ to generate an enormous amount of Ca₃(PO₄)₂ and promoted the reduction of iron oxides. However, the growth of iron particles was inhibited. With the addition of Na₂CO₃, the phosphorus in Fe₃PO₇ migrated to nepheline and Na₂CO₃ improved the reduction of iron oxides and growth of iron particles. Therefore, the recovery of iron and the separation of iron and phosphorus were the best. In contrast, CaF₂ reacted with Fe₃PO₇ to form fine Ca₃(PO₄)₂ particles scattered around the iron particles, making the separation of iron and phosphorus difficult.     

不同硅饱和系数水榴石的碳酸化分解动力学

Carbonated decomposition of hydrogarnet is one of the vital reactions of the calcification–carbonation method, which is designed to dispose of low-grade bauxite and Bayer red mud and is a novel eco-friendly method. In this study, the effect of the silica saturation coefficient (x) on the carbonation of hydrogarnet was investigated from the kinetic perspective. The results indicated that the carbonation of hydrogarnets with different x values (x = 0.27, 0.36, 0.70, and 0.73) underwent two stages with significantly different rates, and the kinetic mechanisms of the two stages can be described by the kinetic functions R3 and D3. The apparent activation energies at Stages 1 and 2 were 41.96–81.64 and 14.80–34.84 kJ/mol, respectively. Moreover, the corresponding limiting steps of the two stages were interfacial chemical reaction and diffusion.     

一种超重力燃烧合成制备高性能高熵合金的新方法

A new method of high-gravity combustion synthesis (HGCS) followed by post-treatment (PT) is reported for preparing high-performance high-entropy alloys (HEAs), Cr_0.9FeNi_2.5V_0.2Al_0.5 alloy, whereby cheap thermite powder is used as the raw material. In this process, the HEA melt and the ceramic melt are rapidly formed by a strong exothermic combustion synthesis reaction and completely separated under a high-gravity field. Then, the master alloy is obtained after cooling. Subsequently, the master alloy is sequentially subjected to conventional vacuum arc melting (VAM), homogenization treatment, cold rolling, and annealing treatment to realize a tensile strength, yield strength, and elongation of 1250 MPa, 1075 MPa, and 2.9%, respectively. The present method is increasingly attractive due to its low cost of raw materials and the intermediate product obtained without high-temperature heating. Based on the calculation of phase separation kinetics in the high-temperature melt, it is expected that the final alloys with high performance can be prepared directly across master alloys with higher high-gravity coefficients.     

窄板坯结晶器内连铸工艺参数对钢液流场的影响

Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow field in slab continuous casting (CC) molds with narrow widths for the production of automobile exposed panels. Reasonable agreement between the calculated results and measured subsurface velocities of liquid steel was obtained under different operating parameters of the CC process. The simulation results reveal that the flow field in the horizontal plane located 50 mm from the meniscus can be used as the characteristic flow field to optimize the flow field of molten steel in the mold. Increases in casting speed can increase the subsurface velocity of molten steel and shift the position of the vortex core downward in the downward circulation zone. The flow field of liquid steel in a 1040 mm-wide slab CC mold can be improved by an Ar gas flow rate of 7 L·min?1 and casting speed of 1.7 m·min?1. Under the present experimental conditions, the double-roll flow pattern is generally stable at a submerged entry nozzle immersion depth of 170 mm.     

电渣重熔脱硫技术研究进展

Electroslag remelting (ESR) gives a combination of liquid metal refining and solidification structure control. One of the typical aspects of liquid metal refining during ESR for the advanced steel and alloy production is desulfurization. It involves two patterns, i.e., slag–metal reaction and gas–slag reaction (gasifying desulfurization). In this paper, the advances in desulfurization practices of ESR are reviewed. The effects of processing parameters, including the initial sulfur level of consumable electrode, remelting atmosphere, deoxidation schemes of ESR, slag composition, melting rate, and electrical parameters on the desulfurization in ESR are assessed. The interrelation between desulfurization and sulfide inclusion evolution during ESR is discussed, and advancements in the production of sulfur-bearing steel at a high-sulfur level during ESR are described. The remaining challenges for future work are also proposed.     

利用皮秒激光烧蚀制备非球形铝纳米颗粒

We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid (chloroform, CHCl₃) with ~2 ps laser pulses at an input energy of ~350 μJ. The synthesized aluminum nanoparticles exhibited a surface plasmon resonance peak at ~340 nm. Scanning electron microscopy images of Al nanoparticles demonstrated the spherical morphology with an average size of (27 ± 3.6) nm. The formation of smaller spherical Al nanoparticles and the diminished growth could be from the formation of electric double layers on the Al nanoparticles. In addition to spherical aluminum nanoparticles, triangular/pentagonal/hexagonal nanoparticles were also observed in the colloidal solution. Field emission scanning electron microscopy images of ablated Al targets demonstrated laser induced periodic surface structures (LIPSSs), which were the high spatial frequency LIPSSs (HSF-LIPSSs) since their grating period was ~280 nm. Additionally, coarse structures with a period of ~700 nm were observed.     

Mineral transition and formation mechanism of calcium aluminate compounds in CaO?Al2O3?Na2O system during high-temperature sintering

The mineral transition and formation mechanism of calcium aluminate compounds in CaO?Al₂O₃?Na₂O system during the high-temperature sintering process were systematically investigated using DSC?TG, XRD, SEM?EDS, FTIR, and Raman spectra, and the crystal structure of Na₄Ca₃(AlO₂)₁₀ was also simulated by Material Studio software. The results indicated that the minerals formed during the sintering process included Na₄Ca₃(AlO₂)₁₀, CaO·Al₂O₃, and 12CaO·7Al₂O₃, and the content of Na₄Ca₃(AlO₂)₁₀ could reach 92wt% when sintered at 1200°C for 30 min. The main formation stage of Na₄Ca₃(AlO₂)₁₀ occurred at temperatures from 970 to 1100°C, and the content could reach 82wt% when the reaction temperature increased to 1100°C. The crystal system of Na₄Ca₃(AlO₂)₁₀ was tetragonal, and the cells preferred to grow along crystal planes (110) and (210). The formation of Na₄Ca₃(AlO₂)₁₀ was an exothermic reaction that followed a secondary reaction model, and its activation energy was 223.97 kJ/mol.     

含细夹层的分矿充填层中流动特性的可视化

Ore particles, especially fine interlayers, commonly segregate in heap stacking, leading to undesirable flow paths and changeable flow velocity fields of packed beds. Computed tomography (CT), COMSOL Multiphysics, and MATLAB were utilized to quantify pore structures and visualize flow behavior inside packed beds with segregated fine interlayers. The formation of fine interlayers was accompanied with the segregation of particles in packed beds. Fine particles reached the upper position of the packed beds during stacking. CT revealed that the average porosity of fine interlayers (24.21%) was significantly lower than that of the heap packed by coarse ores (37.42%), which directly affected the formation of flow paths. Specifically, the potential flow paths in the internal regions of fine interlayers were undeveloped. Fluid flowed and bypassed the fine interlayers and along the sides of the packed beds. Flow velocity also indicated that the flow paths easily gathered in the pore throat where flow velocity (1.8 × 10?5 m/s) suddenly increased. Fluid stagnant regions with a flow velocity lower than 0.2 × 10?5 m/s appeared in flow paths with a large diameter.     

PRIMARY APPLICATION OF THE WATER SOLUBLE POLYURETHANE (WPU) TO PROTEIN FABRICS

The primary application of the water soluble polyurethane (WPU) in protein fabrics was investigated. Both WCRA (wet crease recovery angle ) and DCRA ( dry crease recovery angle ) of silk fabrics finished with WPU were increased, and the other properties were only slightly influenced. As a formaldehyde - free silk finishing agent, WPU was proved to have a great future. The felting shrinkage ratio of wool fabrics treated by only WPU was reduced to 12.5% from 36.7%. On the basis of Oxidation/ Resin process, the felting shrinkage ratio of treated wool was 8.7%, and almost reached "Machine washable" level.     

棉梭织面料潮态免烫整理工艺研究

采用免烫整理树脂KNITTEX FA CONC在低温条件下对棉梭织面料进行潮交联,通过对织物残留含潮率、催化剂用量、树脂用量、堆置反应时间、工作液pH值的研究,确定了免烫树脂整理棉梭织面料的最优工艺参数:织物残留含潮率7%,催化剂用量130g/L,树脂用量200g/L,堆置反应时间应在16h,pH值控制在2.0左右.相对于干态交联,经该整理工艺处理的棉梭织面料抗皱免烫效果好,甲醛含量符合国家相关法令.     

氧化淀粉胶液中游离甲醛含量的测定

游离甲醛含量的测定方法很多 ,通过对比现有不同产品体系中游离甲醛的测定方法 ,提出了氧化淀粉胶液中游离甲醛的测定方法 ,为淀粉类材料及液体制剂中的游离甲醛的测定提供了依据     

室内装饰装修材料中甲醛的限量及测定

室内装饰装修材料所致的室内空气污染以及由此引发的健康问题已引起人们的普遍关注.甲醛是一种高挥发性有机物,污染源多,污染浓度高,持续时间长,是极为重要的室内污染物.文章就室内装饰装修材料中游离甲醛的危害、来源进行了分析,重点论述了各种室内装饰装修材料中游离甲醛的限量及测定的原理、方法,以便人们正确控制室内装饰装修材料中的游离甲醛及其使用过程中释放的甲醛.     

TiO2/Polyester Non-woven Fabrics as a Kind of Photocatalyst for the Degradation of Formaldehyde Gas

The feasibility of photocatalytic degradation of the formaldehyde gas by titanium dioxide （TiO2）/polyester non-woven fabrics was studied. Tbe effects of parameters such as tbe concentration of TiO2 solution, pH value, and drying temperature on the photocatalytic degradation of the formaldehyde gas were also studied. The results showed that the photodegradation efficiency of the formaldehyde gas increased rapidly with the increasing of the concentration of TiO2 solution up to 15g/L, but when the concentration was in excess of 15g/L, the photodegradation efficiency decreased gradually and fluctuated due to light obstruction and disperse state of TiO2. Adjusting the pH value in the solution, the efficiency of photocatalytic degradation of the formaldehyde gas could be improved. The mechanisms of the reaction and the role of the additives were also investigated. After 42hours, TiO2/ polyester non-woven fabric showed no significant loss of the photocatalytic activity.     

高性能环保型木质素基酚醛胶粘剂的制备

采用酚化技术制备了低成本和低游离酚、醛的木质素基酚醛胶粘剂(LPF).利用单因素实验法,探讨了加料方式对传统酚醛树脂(PF)胶粘剂游离酚、醛的影响;实验考察了酚化木质素以及用木质素酚化产物代替苯酚制备LPF胶的影响因素,优化得到高性能环保型LPF的配方工艺;并采用红外光谱测试了木质素在酸催化条件下酚化改性后的结构变化.结果表明,木质素分子在酚化条件下发生降解,通过酚化反应羟基含量显著提高,并产生了新的具有不同取代基的苯环结构;以苯酚为液化试剂,用浓盐酸作催化剂、浓盐酸用量为3%、液化温度为120℃、液化时间为10min、酚木比为2:1,酚化得到的木质素酚化液,在酚醛比为1:1.8时,甲醛分3次加入、碱液分2次加入,制备得到的LPF具有比传统PF更低的游离酚、醛含量、优异的胶合性能和储存稳定性.     

游离甲醛的简易检测

甲醛既是重要的有机合成原料 ,又是主要的环境污染物 ,简便快捷地检测出工业废水及某些化工产品中的游离甲醛非常重要。文中对品红醛试剂这一简便检测甲醛的方法做了研究 ,得出了甲醛含量对照表(表 1) ,并讨论其影响因素 ,指出了品红醛试剂检测甲醛的使用条件     

低毒脲醛树脂粘合剂的研究

介绍了含游离甲醛低的粘结强度大的建筑行业用脲醛树脂粘合剂的制备方法。研究了树脂合成过程中原材料纯度 ,尿素和甲醛的摩尔比 ,反应温度以及反应时间对粘合剂粘度和固含量等性能的影响。在一定酸度和温度条件下 ,分批加入尿素进行阶段控温反应 ,得到一种胶液性能稳定 ,粘接强度高的建筑板材专用粘合剂     

乙二醛/尿素树脂的合成及在造纸上的应用

尿醛树脂是一种传统的纸张施胶剂,由于其廉价,而且施强效果明显,因此一直被广泛的应用。但它在生产和使用过程中容易释放出游离甲醛,带来极大的健康危害。该文研究了以乙二醛部分或全部替代甲醛合成脲醛树脂的合成条件以及产物对纸张产生的湿增强效果,并通过光谱分析初步探讨了乙二醛、甲醛、尿素合成脲醛树脂的反应机理及作为纸张湿强剂的湿增强机理