Accelerating the decarbonization of carbonaceous gold ore by suspension oxidation roasting towards the improvement of gold leaching efficiency

Eliminating the gold preg-robbing effect of carbonaceous matter in carbonaceous gold ores is crucial for gold leaching. In this study, suspension oxidation roasting was proposed to accelerate the decarbonization of carbonaceous gold ore. The characteristics of oxidation reaction process and gas release were analyzed by TG-DTA-FTIR. The phase transformation and microstructure evolution of samples during roasting were analyzed by XRD, SEM and BET. The results show that the gold preg-robbing effect was eliminated after the gasification of carbonaceous matter, and the CaO generated by decomposition of carbonates can effectively capture the SO₂. After roasting for 75 min at 650 °C in a 20% O₂ atmosphere, the total carbon removal rate reached 99.42%, the distribution of exposed gold increased from 28.85% to 77.10% and the gold leaching efficiency increased from 4.55% to 84.83%. In addition, about 70% sulfur was mainly fixed in the roasted products in the form of sulfate. Therefore, the suspension oxidation roasting process is an efficient and clean pretreatment method for carbonaceous gold ores.     

Magnetic field-enhanced photocatalytic nitrogen fixation over defect-rich ferroelectric Bi2WO6

Photocatalytic N₂ fixation is a promising and sustainable manufacturing process of ammonia (NH₃); however, the NH₃ production rate by this method is very low, thus severely restricting further application of this sustainable technology. Therefore, developing an efficient photocatalyst for N₂ fixation under mild conditions is urgently required. Herein, ferroelectric Bi₂WO₆ materials with different surface oxygen defects were prepared, and the concentration of corresponding defects was controlled by adjusting the thermal reduction time. The abundant oxygen defects in Bi₂WO₆ can provide more reactive sites to promote the effective adsorption of N₂, and the photogenerated charge carrier can be efficiently separated benefiting from the internal electric field. These would weaken the N₂ triple bond and reduce the activation energy barrier for the conversion of N₂ to NH₃ under mild conditions. In the absence of sacrificial agents and cocatalysts, the optimized Bi₂WO₆ with oxygen defects shows an indigenous NH₃ yield of 132.175 μmol·g^-1·L^-1·h^-1, which is more than two times higher than that of the original Bi₂WO₆. Surprisingly, the Bi₂WO₆ with oxygen defects produced more than eight times NH₃ (471.13 μmol·g^-1·L^-1·h^-1) than that of the original Bi₂WO₆ when assisted by an external magnetic field, thus providing a new perspective for further enhancing the N₂ fixation performance.     

中国钢化联产发展现状与前景展望

中国是一个钢铁生产大国,也是一个油气资源相对不足、煤炭资源相对丰富的国家。基于中国能源结构的实际情况,结合钢铁行业和化工行业的发展现状,讨论了钢铁生产各个工序煤气的发生与使用情况,并对钢铁流程副产煤气合成化工产品的现状与潜力进行了分析,指出了存在的问题。结合分析结果,提出了未来可再生能源廉价制氢发展达到一定阶段,钢铁联合企业可以通过“以氢固碳”实现钢铁生产大规模减少CO₂排放的目标,提升其清洁能源转化与高附加值化工产品生产的社会功能。最后,对未来中国钢化联产的发展提出了建议。     

Conversion of dinitrogen to ammonia by rhenium doped graphyne

Developing efficient catalysis for dinitrogen (N₂) fixation is a very important and challenging issue in chemistry. Herein, by means of density functional theory (DFT) computations, we reported that the potential of single-atom Rhenium (Re) supported on the graphyne (Re-GY) for activating N₂ and reducing it into ammonia (NH₃). It is found that the adsorption energies of N₂ on Re-GY for end-on/side-on configuration are −1.05/-0.56 eV, together with the N–N bond length are stretched to 1.14/1.21 Å, respectively. The hydrazine intermediate is difficult to release with adsorption energies of −1.71/1.49 eV on Re-GY for different pathways, which ensures it is sequentially hydrogenated and eventually form NH₃. All the mechanisms considered are energetically favorable and the most favorable pathway is the mixed mechanism. It is worth noting that there are relatively rare researches on Re-based catalysts for N₂ fixation, our findings provide a new option for the design and synthesis of catalysts for N₂ reduction reaction.     

涤纶浸染用高固色率液体分散染料

研究了菲诺CLT型液体分散染料的粒径、扩散性、高低温分散性和储存稳定性等基本性能;分析了液体分散染料的染色上染率、移染性和提升性等应用性能;对比了常规粉状染料和液体分散染料的浸染染色残液。结果表明,CLT型液体分散染料颗粒细致均匀,扩散性、高低温分散性能和存储稳定性优异。三只液体分散染料上染曲线、移染性和提升性相近,染料组合配伍性好。     

连续蓄热式生物质气化/燃烧供热系统

生物质能源是一种环境友好的可再生能源,但也存在能量密度低、含水率高、碱金属含量高等缺点,导致其在热利用的过程中存在易结渣、堵灰及腐蚀、热效率不高等问题。本文结合生物质气化、炉内碱金属/硫固定、两级焦油裂解、蓄热式燃烧,以及冷凝热回收等多项先进技术,设计并搭建了连续蓄热式生物质气化/燃烧供热系统。以海洋贝壳类废弃物作为生物质成型燃料的添加剂和生物质焦油裂解过程的催化剂,在实现海洋废弃资源高值化利用的同时,克服了生物质热利用过程中的多项障碍,能够显著提高生物质能热利用效率,同时大幅度降低当前工业及民用供热过程中CO₂、SO_x、NO_x及烟尘的排放,具有良好的经济性与环保性。     

Salience computation in images based on perceptual distinctness

A salience computation approach based on perceptual distinctness is proposed in this paper that predicts human eye fixation locations in images. The approach uses a novel representation of pattern in a patch around a pixel such that discrimination between patterns is in compliance with distinctness between them in-terms of a few well-known perceptual cues. Image patches of different sizes (resolutions) are considered. The representations of the value at and pattern around a pixel in different features such as lightness, color and orientation are discriminated from all those in the rest of the image to compute salience at that pixel. The effectiveness of the proposed salience computation approach in generating salience maps closer to human eye fixation density maps is demonstrated by comparing it both qualitatively and quantitatively to other existing state-of-the-art salience computation approaches. Several synthetic images and psychological patterns, and real-life images from five well-known datasets are considered for this purpose.     

注塑材料在电机转子磁钢固定中的分析与应用

为提高电机转子磁钢固定的可靠性和经济性，本文采用了转子注塑工艺来对转子磁钢进行固定。通过对注塑材料的性能分析与验证确定注塑材料的可靠性。通过对转子注塑工艺进行验证，确定了注塑工艺参数，保证了注塑工艺的可行性。     

Synthetic curli enables efficient microbial electrocatalysis with stainless-steel electrode

Microbial electrocatalysis systems (MES) provide a cutting-edge solution to global problems associated with the environment and energy, but practical applications are hindered by the expensive electrode materials. Although stainless steel (SS) has been proposed as a promising inexpensive candidate, poor cell/SS interaction results in a low performance for MES. Here, a new synthetic biology approach was established for reinforcing the cell/SS interaction. Hybridized curli nanofibers fused with a metal-binding domain were heterogeneously expressed onto the cell surface, which realized efficient cell binding with the SS electrode. Consequently, it enabled a ~420-fold improvement of the anodic power output and a substantial enhancement of the cathodic Coulombic efficiency (from 0.6 to 4% to over 80%) with an SS electrode. This work demonstrates low-cost MES with an SS electrode and introduces a new avenue to engineer the cell/electrode interaction, which is promising for future practical applications of MES.