铜渣复合硅锰水淬渣后的改质提铁研究

铜材等金属材料在生产过程中产生的大量水渣、干渣等冶金渣,其综合利用水平较低,成为冶金业高质量绿色发展亟须解决的难点。为有效回收铜渣中的铁元素,将工业铜渣与硅锰水淬渣混合后按一定比例添加氧化钙及氧化锰进行成分改质,利用FactSage对混合渣料中矿物相随温度的变化趋势进行了预测,借助XRD对改质前后渣料中的矿物相变化进行了对比,通过SEM和EDS对改质后混合渣料中主要矿物相的形态、分布和特征进行了表征。实验结果表明：改质后混合渣料中的矿物相以尖晶石相和硅酸盐相为主;碱度提高后,改质样品中的硅酸盐相增多但尖晶石相减少;混合渣料的碱度为1.5时改质效果最好,其铁品位为44%（质量分数）、铁回收率为95%。     

氟化铝生产副产物-硅渣酸化过程及其动力学

为解决实际生产中氟化铝生产残渣(简称硅渣)难利用问题,以云南某地硅渣为研究对象,以浓硫酸为酸化浸出介质,以浸出率为指标,以单因素实验为基础,研究了酸化过程中酸用量、反应温度、反应时间的影响。结果表明,最佳酸化条件为：加入理论酸用量(23.66 g) 1.3倍的浓硫酸,反应温度170℃,反应时间90 min,该条件下SiO₂的纯度迅速提升至大于99.00%,Al浸出率大于99%,F浸出率大于97%;该反应为液-固多相反应中的收缩未反应核模型,反应活化能为62.97 kJ/mol,浸出过程由化学反应控制。该方法的提出对硅渣的利用提供了一种新思路,具有反应时间短、耗水少、酸化后有价元素浸出率高的优点。     

Synthesis and characterization of precursor derived TiN@Si–Al–C–N ceramic nanocomposites for oxygen reduction reaction

The development of efficient and durable catalysts is critical for the commercialization of fuel cells, as the catalysts’ durability and reactivity dictate their ultimate lifetime and activity. In this work, amorphous silicon-based ceramics (Si–C–N and Si–Al–C–N) and TiN@Si–Al–C–N nanocomposites were developed using a precursor derived ceramics approach. In TiN@Si–Al–C–N nanocomposites, TiN nanocrystals (with sizes in the range of 5–12 nm) were effectively anchored on an amorphous Si–Al–C–N support. The nanocomposites were found to be mesoporous in nature and exhibited a surface area as high as 132 m²/g. The average pore size of the nanocomposites was found to increase with an increase in the pyrolysis temperature, and a subsequent graphitization of free carbon was observed as revealed from the Raman spectra. The ceramics were investigated for electrocatalytic activity toward the oxygen reduction reaction using the rotating disk electrode method. The TiN@Si–Al–C–N nanocomposites showed an onset potential of 0.7 V versus reversible hydrogen electrode for oxygen reduction, which seems to indicate a 4-electron pathway at the pyrolysis temperature of 1000°C in contrast to a 2-electron pathway exhibited by the nanocomposites pyrolyzed at 750°C via the Koutecky–Levich plot.     

Effect of BN nanoparticle content in SiC matrix on microstructure and mechanical properties of SiC/SiC composites

BN-nanoparticle-containing SiC-matrix-based composites comprising SiC fibers and lacking a fiber/matrix interface (SiC/BN + SiC composites) were fabricated by spark plasma sintering (SPS) at 1800°C for 10 min under 50 MPa in Ar. The content of added BN nanoparticles was varied from 0 to 50 vol.%. The mechanical properties of the SiC/BN + SiC composites were investigated thoroughly. The SiC/BN + SiC composites with a BN nanoparticle content of 50 vol.%, which had a bulk density of 2.73 g/cm³ and an open porosity of 5.8%, exhibited quasiductile fracture behavior, as indicated by a short nonlinear region and significantly shorter fiber pullouts owing to the relatively high modulus. The composites also exhibited high strength as well as bending, proportional limit stress, and ultimate tensile strength values of 496 ± 13, 251 ± 30, and 301 MPa ± 56 MPa, respectively, under ambient conditions. The SiC fibers with contents of BN nanoparticles above 30 vol.% were not severely damaged during SPS and adhered to the matrix to form a relatively weak fiber/matrix interface.     

Evaluation of tribological behavior of silicon carbide and silicon nitride ceramics under different conditions

A comparative analysis of the tribological behavior of commercially available sintered silicon carbide (SiC) and three different types of silicon nitride (Si₃N₄) ceramics have been carried out using the ball-on-disk method in dry and lubrication (deionized [DI] water and ethanol) environment. Scanning electron microscopy (SEM) was used to understand the morphology and chemical composition of the tribo-surfaces. Sintered SiC (Hexoloy-SA) had the highest friction coefficient during dry sliding with an average of ∼0.34. Deionized water showed a minor improvement in friction (∼0.27) while ethanol reduced the friction greatly to ∼0.18 compared to dry sliding. During dry sliding, the presence of an abrasive third body was responsible for the high wear rates (WRs) in these compositions. Hexoloy-SA showed a lower WR during ethanol and DI water lubrication due to the formation of stable tribofilms as well as higher hardness which resisted the formation of third bodies. In comparison, Si₃N₄ samples showed a lower WR in DI water and ethanol. The samples also showed composition-dependent behavior which indicates that grain structure and grain boundary chemistry are playing a vital role in the tribological process.     

有机硅改性菜油皮革加脂剂的合成

菜油和甲醇进行酯交换反应,再与有机硅单体(D4)进行接枝,进一步硫酸化改性得到有机硅改性菜油皮革加脂剂。其乳液性能稳定,含有多种活性基,和皮革结合性好,同时具有防水功能。     

多重量子阱光致发光及表面本征态数值分析

建立了量子阱的物理模型．通过变分法和数值逼近法分析了多重量子阱光致发光现象及能量本征值和本征函数．采用的量子线多孔硅（PS）量子阱在分析光致发光特性上是比较显著的．能量修正中，无论在弱场中或强场中，变分法优于微扰法．对于光致发光的强度分析，量子阱的重数逐渐增多，更接近于实验值。     

硅纳米孔结构在多晶硅太阳能电池中的应用

利用金属辅助化学刻蚀及碱修饰方法在多晶硅上制备了硅纳米孔结构,比较了硅纳米孔结构和酸制绒常规多晶硅硅片在反射、内量子效率、磷浓度分布以及电池性能等方面的情况。研究表明,硅纳米孔结构多晶硅太阳能电池开压为0.6261V,短路电流为8.683A,填充因子为79.06%,效率为17.66%,比酸制绒常规电池片高出0.23%。     

无取向硅钢冶炼过程中的夹杂物遗传变化

研究表明,硅钢中的夹杂物对成品带钢的磁性能有显著影响。为研究冶炼过程硅钢中的夹杂物遗传变化,进而提出更有效的控制措施加以去除,本文结合典型的无取向硅钢生产炉次,采用非水溶液电解提取+扫描电镜观察方法分析冶炼过程中上述炉次典型试样的夹杂物。结果表明:转炉冶炼结束、RH精炼开始时,钢的氧化物夹杂总量最大,约为0.23%;RH精炼过程中,氧化物夹杂总量不断降低,并在脱碳结束时达到最低,约为0.02%;连铸过程中,氧化物夹杂总量仍有不断降低趋势,但夹杂物的平均尺寸变化不大。本试验条件下,中间包试样的夹杂物数量约为1.59×104个/mm3。     

耐溶剂型阳离子聚氨酯封底剂的合成及应用

以甲苯二异氰酸酯、聚醚二元醇、羟基硅油、叔胺二元醇为主要原料 ,经预聚、扩链、引入亲水基、季铵化反应、乳化等过程 ,制得固含量为 2 0 %的耐溶剂型有机硅改性阳离子聚氨酯乳液。胶膜浸泡于水、甲苯中 72h后 ,膜分别增重 2 3 .1 % ,2 5 0 % ,在甲苯中 3 0d ,膜仍保持完整。用于牛鞋面革涂饰 ,提高乳液对坯革的润湿、铺展性能 ,涂层更均匀 ,且耐甲苯、醋酸丁酯的浸渍。