Investigation of the energy-size reduction and mineral liberation of raw coal in the Hardgrove mill

Raw coal was ground in a Hardgrove mill, and mineral liberation from coal was investigated by float-sink test and electron probe microanalyzer (EPMA). Based on EPMA, associated conditions of mineral were determined. Analyses of energy-size reduction show that energy efficiency decreases with time. For +0.074 mm progenies, yields of particles in ?1.5 g.cm^?3 decrease with the increase of size and time, and products in +1.8 g.cm^?3 show the opposite trend. EPMA of 0.25–0.125 mm, 1.5–1.8 g.cm^?3 products ground for 10 min indicates that only part of minerals are liberated. For ?0.074 mm products, the yield of particles in ?1.5 g.cm^?3 decreases by 23.36% in last several minutes, but ash content of +1.8 g.cm^?3 also decreases by 13.18%. Since breakage of raw coal in last 9 min does not reduce particle size obviously, and liberation degree cannot be improved dramatically, closed grinding of 10 min in Hardgrove mill is proper to balance the size reduction and mineral liberation.     

不同降雨入渗条件下预应力锚索加固边坡稳定性分析

为了研究不同降雨条件下边坡安全系数及预应力锚索轴力变化规律,以省道S303沿线某边坡为研究对象,考虑土体饱和-非饱和渗流与非饱和强度理论,基于有限元分析,对不同降雨工况下的孔隙水压分布、锚索轴力及采用强度折减法计算的边坡安全系数变化规律进行了研究。结果表明: 降雨量一定时,降雨入渗范围随雨强增大而减小,暂态饱和区域随雨强增加而增大; 边坡在加固前后的安全系数均随降雨量增加而不断减小,采用预应力锚索加固能有效提高边坡安全系数,并减小降雨对边坡稳定性的影响; 随着降雨量增加,各锚索轴力均增大,当降雨量一定时,雨强越小,对应的锚索轴力提升幅度越大,靠近底部的锚索轴力对降雨最为敏感。     

Physicochemical and technological properties of beef burger as influenced by the addition of pea fibre

This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance.     

煤磨热风管道改造的效果

中联万基水泥有限公司4500t/d熟料生产线采用SCLW4-12×13.4第四代篦冷机,煤磨热风取风口和余热发电AQC热风取风口在篦冷机同一对称位置,煤磨与余热发电系统存在争风现象,开停煤磨对余热发电系统影响较大。通过从废气管道处开孔,加装管道和电动阀,与热风管道汇合通往煤磨沉降室,调整相应阀门开度,可以控制入煤磨烟气温度,这样不但提高了余热发电量,而且提高了煤磨产量,同时也降低了窑头排风机的负荷,降低了熟料生产电耗。     

高频氢等离子体增强还原制备超细铜粉

利用高频感应热氢等离子体强化还原制备超细铜粉，考察了加料速率、还原氢气流量、氢气分布位置、反应区空间、冷却温度等因素对铜粉颗粒性能的影响，对制备的铜粉颗粒进行氧含量、XRD晶体结构、松装密度、粒度分布和比表面积的表征。结果表明，优化的工艺条件为反应区内径100 mm，加料速率4 g/min，淬火气氩气气量500 L/h，氢气气量500 L/h并通入少量载气，由氢等离子电离产生的氢自由基可强化反应实现瞬时还原，不仅可控制铜粉形貌，还能有效控制铜粉颗粒大小；利用该方法制备出粒径分布100?200 nm、分散性好的超细球形铜粉颗粒。该方法操作简便、产品纯度高、气氛可控、对环境污染小。     

Deposition of nanostructured LSM perovskite thin film on dense YSZ substrate by airbrushed solution combustion (ASC) for application in SOFC cathodes

To make SOFC high efficiency energy generation devices, thin ceramic films are proposed as their main components. The rate of the oxygen reduction reaction is relevant for the overall performance of the SOFC, hence a lot of attention is given to the cathodes and their interfaces. The airbrushed solution combustion (ASC) method was used to fabricate an LSM thin film on a dense YSZ substrate. A single phase LSM perovskite was obtained with very thin and interconnected porosity, and a small average grain size (55 nm). The nanostructured LSM thin film electrode showed a low total activation energy (1.27 eV) at high temperatures, but a high area specific resistance at 850°C (55 Ω.cm²). The activation energy for the dissociative adsorption and diffusion of oxygen was significantly low (1.27 eV), while the charge transfer and oxygen ion migration activation energy at the LSM/YSZ interface (1.28 eV) was closer to those usually reported.     

Microwave dielectric properties of SrLa[Ga1−x(Mg0.5Ti0.5)x]O4 and SrLa[Ga1−x(Zn0.5Ti0.5)x]O4 (x = 0.2-0.8) ceramics

SrLa[Ga_1−x(R_0.5Ti_0.5)_x]O₄ (R = Mg, Zn) ceramics were prepared by a standard solid state sintering method. The single-phase ceramics with K₂NiF₄-type layered perovskite structure and I4/mmm space group were obtained, indicating that SrLa(R_0.5Ti_0.5) and SrLaGaO₄ can form the unlimited solid solutions. With increasing x for R = Mg and Zn, ε_r increases monotonously, the Qf value first increases and then decreases, while τ_f increases from a negative to a positive value. The optimized microwave dielectric properties were obtained as following: ε_r = 23.3, Qf = 89 400 GHz, τ_f = −0.8 ppm/°C for SrLa[Ga_0.6(Mg_0.5Ti_0.5)_0.4]O₄ and ε_r = 23.3, Qf = 76 200 GHz, τ_f = 0.2 ppm/°C for SrLa[Ga_0.7(Zn_0.5Ti_0.5)_0.3]O₄, indicating that the present solid solution ceramics are the promising candidates as microwave resonator materials for the telecommunication applications.     

Magnetoelectric,magnetodielectric effect and dielectric,magnetic properties of microwave-sintered lead-free x(Co0.9Ni0.1Fe2O4)-(1-x)[0.5(Ba0.7Ca0.3TiO3)-0.5(BaZr0.2Ti0.8O3)] particulate multiferroic composite

Materials with two distinct (magnetostrictive-ferroelectric) phases, i.e., x (Co_0·9Ni_0·1Fe₂O₄) -(1-x) [0.5 (Ba_0·7Ca_0·3TiO₃) −0.5 (BaZr_0·2Ti_0·8O₃)], combined at ratios of 10:90, 20:80, 30:70, and 40:60 were prepared using a hydroxide coprecipitation method. These multiferroic composites were subjected to sintering via the hybrid microwave sintering technique at 1200 °C for 20 min. Ni-substituted CFO exhibited excellent magnetic properties at room temperature, with Ms ≈ 80 emu/g, μB ≈ 3.37, Mr ≈ 19.05 emu/g, and Hc ≈ 599 Oe, as well as a high value of the magnetostriction coefficient (λ12 ≈ −118 ppm). The magnetostrictive-ferroelectric crystal phases in each composite were confirmed via X-ray diffraction analysis. The highest value of the linear magneto-electric coefficient was α = 21.6 mV/cm-Oe at a frequency of 1 kHz for the 40CNFO-60(BCT-BZT) composite, and a similar sample had the highest value of the magnetodielectric coefficient, which was approximately 3.3% at f = 1 kHz with an applied magnetic field of 1 T. The typical ferromagnetic and ferroelectric nature of each composite was confirmed by M − H and P–E hysteresis loops, respectively at room temperature. Two anomalies were observed in the temperature-dependent dielectric permittivity one at ~140 °C and another above 500 °C confirming the coexistence of two materials with distinct transition points, i.e., BCT-BZT and CNFO, respectively.     

电催化氮气还原合成氨催化材料研究进展

氨是纺织、制药、化肥等领域重要的化工原料，也是一种清洁的能源载体，需求量大。目前氨的工业生产主要为Haber-Bosch法，反应条件严苛，能源消耗大且碳排放较高。电催化氮气还原(NRR)合成氨是一种在常温常压下进行的反应，工作电位低，且电能可通过清洁能源提供，是一种很有潜力的合成氨新工艺。但目前电催化NRR材料的产氨速率和法拉第效率低、工作稳定性不够高、溶液中痕量氨的定量检测困难及检测标准不统一等都为其发展带来了巨大挑战。本文首先介绍了电催化NRR的反应机理和常用研究方法，然后重点梳理了2019年以来NRR催化材料的最新研究进展，最后对该领域研究面临的挑战和机遇进行了展望。     

微波耦合铁碳微电解预处理石化废水的试验

采用微波耦合铁碳微电解技术对石化废水进行预处理,并对预处理前后水样中有机物的变化进行分析。结果表明,原水CODCr为10 500 mg/L,在废水pH值为3、铁碳投加量为20%、微波功率为700 W,经微波辐射5 min处理后,出水CODCr为2 370 mg/L左右,COD去除率稳定在77%左右,提高了废水的可生化性。GC-MS和三维荧光分析结果均表明,微波耦合铁碳微电解处理后,试验废水中有机物的数量及浓度大幅降低。结合后续生化处理,可以达到三级污水综合排放标准(GB 8978-1996)。微波耦合铁碳微电解可作为石化废水的有效预处理方法。