窑灰作脱硫剂的水泥窑湿法脱硫系统优化

针对水泥窑生产工艺中生料磨启停工序引起的烟气温度、二氧化硫浓度对湿法脱硫系统的影响以及杂质对湿法脱硫系统设备和浆液储罐的影响,提出了优化设计方法和运行措施,以便达到较好的烟气脱硫效果。实践表明,该工艺综合循环利用窑灰作脱硫剂,不仅可将烟气中二氧化硫能够达标排放,而且脱硫副产物石膏可作为水泥缓凝剂添加料,有较好的工程应用价值。     

用SiO2微粉制备碳化硅粉体的研究

为回收利用SiO2微粉,探究了以SiO2微粉为原料通过碳热还原法制备碳化硅粉体的最佳工艺条件;研究了分别以石油焦、活性炭和石墨粉为还原剂对冶炼效果的影响。在最佳碳质还原剂的基础上,研究了不同配碳比(还原剂与SiO2微粉的质量比为1∶3.5、1∶3、1∶2.5、1∶2、1∶1.5)和不同冶炼时间(15、30、45、60 min)对冶炼效果的影响。结果表明:石油焦、活性炭、石墨粉3种碳质还原剂中,石油焦的冶炼效果最佳;将石油焦与原料SiO2微粉以质量比1∶2进行混合,在中频感应炉中以1650℃冶炼45 min为最佳冶炼工艺条件;以此能够得到晶粒生长较好、品质较高的碳化硅粉体,碳化硅含量高达93.50%(w)。     

Preparation of composites based on recycled polypropylene and automotive shredder residue

In past research, mechanical recycling of automotive shredder residue (ASR) has led to serious deterioration of material performance, and real‐scale application in this way still remains a challenge. Here, we report a sustainable approach called solid‐state shear milling (SSSM) for the production of high‐performance polypropylene (PP)/ASR composites with robust mechanical performance on a commercial scale. After the SSSM process, the obtained 50/50 wt% PP/ASR composite exhibited a 41.3% increase in tensile strength, 32.9% increase in flexural strength and 55.0% increase in impact toughness when compared with corresponding composites made by traditional direct melt blending. In particular, the toughness of the material can be improved by further addition of PP grafted with maleic anhydride with toughness comparable to that of recycled PP, and a 325% increase in toughness can be obtained with addition of styrene–butadiene–styrene block copolymer grafted with maleic anhydride. This PP/ASR composite shows good processability and high thermal stability, and meets the requirements of many applications for nonstructural products. The approach presented in this paper highlights a novel technique for ASR recycling. © 2018 Society of Chemical Industry     

钙化-酸浸提钒沉钒母液中锰的回收

对钙化?酸浸提钒沉钒母液中锰资源的回收，一方面可以提升提钒工艺的经济效益，另一方面可避免母液循环时锰浓度不断累积而影响氧化钒产品质量，从而有助于实现母液闭路循环而提升全流程的环境效益。本工作提出了采用草酸沉淀法高效回收沉钒母液中的Mn2+，考察溶液体系pH值、草酸加量系数、反应温度和时间对锰回收率及沉淀产物物相组成的影响，以及草酸沉淀分离锰后母液的循环次数对钒浸出过程的影响。结果表明，草酸沉淀法可高效分离沉钒母液中的Mn2+，在溶液体系pH=4.0、草酸加量系数为1.5、反应温度为50℃、反应时间为60 min的条件下，锰回收率达94.33%，所得产物为纯度大于98%的水合草酸锰，为片状晶体，并呈花簇状生长。将脱锰后的沉钒母液循环至酸浸段，对钒浸出率及浸出液中锰的浓度没有明显影响，表明该方法有助于实现钙化?酸浸提钒中废水的闭路循环。     

Hydrometallurgical recovery of zinc from industrial hot dipping top ash

Top ash from hot-dip galvanizing plant was investigated as a source of secondary zinc to be returned to galvanizing bath. The waste material contained 63% Zn as metallic, oxide and hydroxychloride phases. It was leached in H₂SO₄ solutions (20% and 25%) at various bath loadings (100−300 g/L). Leaching behaviors of zinc, manganese, iron and chloride ions were investigated. A few strategies of iron elimination from leaching liquors were examined. Flocculant addition was harmful for subsequent filtration of iron precipitates due to increased viscosity of solution, while a combination of zinc oxide and calcium carbonate for rising pH resulted in the formation of dense suspension unenforceable to separate from zinc sulphate solution. Zinc electrowinning was carried out at different pH (from −0.5 to 2.8) using a range of current densities (3−10 A/dm²). Optimal conditions for pure metal recovery were: leaching in 20% H₂SO₄ solution at zinc ash content 100−150 g/L, Fe₂O₃·xH₂O precipitation using H₂O₂ and CaCO₃, zinc electrowinning at pH of 0.1−1.0 at 3−6 A/dm². Correlations between pH and free H₂SO₄ concentration in electrolyte solutions were also discussed. pH−acid concentration dependence for zinc electrolyte was between experimental and calculated curves for pure H₂SO₄ solutions, while the curve was shifted towards lower pH if ferric ions were in the solution.     

Coherency strain induced hardening in bulk polycrystalline ceramics: A case study with MgO-based “ceramic alloys”

The role of coherency strain at the matrix/precipitate interface toward hardening of bulk polycrystalline “ceramic alloys” has been established here. Formation of “near ideal” bulk polycrystalline ceramic microstructure characterized by the presence of uniformly distributed coherent “ultra-fine” MgCr₂O₄ particles (size: ~25 nm) within matrix (MgO) grains was achieved via solid-state precipitation during aging treatment of bulk supersaturated MgO–Cr₂O₃ solid solutions (formed during pressureless sintering in air, followed by fast cooling). The as-aged MgO–MgCr₂O₄ “ceramic alloys” exhibited hardness increment by ~73% over that of phase pure bulk MgO upon aging for just 10 hours at 1000°C in air. Evidences toward the presence of significant coherency strains across the MgO/MgCr₂O₄ coherent interfaces were obtained with transmission electron microscopy. Analysis based on hardening mechanisms and comparisons with MgO–MgFe₂O₄ system, having lesser hardening due to lower misfit strain at MgO/MgFe₂O₄ coherent interfaces (despite greater content of second-phase particles), confirm the dominant role of coherency strains toward hardness enhancement in “ceramic alloys.”     

Facile synthesis,characterization, and ab-initio DFT simulations of energy efficient NN′ dialkyl 1,4 benzene dicarboxamide monomers recovered from PET bottle waste

Aminolytic chemical recycling is performed for obtaining NN′ diethyl 1,4 benzene dicarboxamide, NN′ dibutyl 1,4 benzene dicarboxamide, and NN′ dihexyl 1,4 benzene dicarboxamide from Polyethylene terephthalate bottle waste. The compounds were characterized through Fourier transform Infrared spectroscopy, Raman spectroscopy, UV–Visible spectroscopy, ¹H NMR, ¹³C NMR, mass spectrometry, and elemental analysis. Thermal properties were also analyzed with the help of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Density Functional Theory (DFT) study has been performed at GGA-BLYP (Becke's and Lee–Yang–Parr) functional using SZ basis set to investigate the vibrational frequencies and physical parameters. Experimental vibrational frequencies were found in good accord with the experimental values. Calorific values of the products have been determined using bomb calorimeter as per standard ASTM D240. The values have been correlated with increment of methylene units from NN′ diethyl BdCA to NN′ dihexyl BdCA using standard molar enthalpies of carbon and hydrogen. SEM and EDX analysis of the char residues after combustion has also been carried out to insight the effect of N-alkyl chain length on calorific values. The calorific values of the recovered compounds are comparable to commercial solid fuels and the compounds may find potential applications in aerospace industry.     

Toward high performance solid-state lithium-ion battery with a promising PEO/PPC blend solid polymer electrolyte

A promising solid polymer blend electrolyte is prepared by blending of poly(ethylene oxide) (PEO) with different content of amorphous poly(propylene carbonate) (PPC), in which the amorphous property of PPC is utilized to enhance the amorphous/free phase of solid polymer electrolyte, so as to achieve the purpose of modifying PEO-based solid polymer electrolyte. It indicates that the blending of PEO with PPC can effectively reduce the crystallization and increase the ion conductivity and electrochemical stability window of solid polymer electrolyte. When the content of PPC reaches 50%, the ionic conductivity reaches the maximum, which is 2.04 × 10⁻⁵ S cm⁻¹ and 2.82 × 10⁻⁴ S cm⁻¹ at 25°C and 60°C, respectively. The electrochemical stability window increases from 4.25 to 4.9 V and the interfacial stability of lithium metal anode is also greatly improved. The solid-state LiFePO₄//Li battery with the PEO/50%PPC blend solid polymer electrolyte has good cycling stability, which the maximum discharge specific capacity is up to 125 mAh g⁻¹ at a charge/discharge current density of 0.5 C at 60°C.     

PET Recycling – Contributions of Crystallization to Sustainability

Polyethylene terephthalate (PET) is one of the most common thermoplastic polymers and its durability has become a major environmental concern. The current public debate on plastic debris also triggered the revision of PET recycling technologies. This Research Article focuses on the chemical recycling of PET by means of methanolysis. The process degrades PET into two main reaction products, dimethyl terephthalate (DMT) and ethylene glycol (EG). Subsequent separation by distillation combined with crystallization removes critical impurities and non-PET components from co-polymers, providing monomers of high purity needed for re-polymerization purposes.     

Aluminiumhydroxychlorid-Flockungsmittel aus dem Kupferrecycling aus Abfällen der Leiterplattenproduktion

The production of printed circuit boards using the printing process produces considerable quantities of copper-containing etching solutions. The copper is recovered from the ammoniacal etching baths by cementation with aluminum waste at ≥ 99 % Cu yield rates. Instead of the usual landfilling, the aluminum-containing solution is processed into a coagulant which can be used in the treatment of mining tailings and wastewater. The aluminum oxychloride produced in this way was characterized in detail and its effectiveness as a flocculant for a finely dispersed system (kaolin suspension) was investigated and confirmed in a jar test.