Effect mechanism of aluminum occurrence and content on the induration characteristics of iron ore pellets

With the intensified depletion of high-grade iron ores,the increased aluminum content in iron ore concentrates has become unavoidable,which is detrimental to the pelletization process.Therefore,the effect mechanism of aluminum on pellet quality must be identified.In this study,the influence of aluminum occurrence and content on the induration of hematite(H)and magnetite(M)pellets was investigated through the addition of corresponding Al-containing additives,including alumina,alumogoethite,gibbsite,and kaolinite.Systematic mineralogical analysis,combined with the thermodynamic properties of different aluminum occurrences and the quantitative characterization of consolidation behaviors,were conducted to determine the related mechanism.The results showed that the alumina from various aluminum occurrences adversely affected the induration characteristics of pellets,especially at an aluminum content of more than 2.0wt%.The thermal decomposition of gibbsite and kaolinite tends to generate internal stress and fine cracks,which hinder the respective microcrystalline bonding and recrystallization between Fe2O3particles.The adverse effect on the induration characteristics of fired pellets with different aluminum occurrences can be relieved to varying degrees through the formation of liquid phase bonds between the hematite particles.Kaolinite is more beneficial to the induration process than the other three aluminum occurrences because of the formation of more liquid phase,which improves pellet consolidation.The research results can further provide insights into the effect of aluminum occurrence and content in iron ore concentrates on downstream processing and serve as a guide for the utilization of high-alumina iron ore concentrates in pelletization.

Current situation of carbon emissions and countermeasures in China's ironmaking industry

The iron and steel industry(ISI) involves high energy consumption and high pollution. ISI in China, a leading country in the ISI,consumed 15% of the country’s total energy and produced more than 50% of the global ISI’s carbon emissions. Therefore, in the context of global low-carbon economy and emission reduction requirements, low-carbon smelting technology in the ISI has attracted increasingly more attention in China. This review summarizes the current status of carbon emissions and energy consumption in China’s ISI and discusses the development status and prospects of low-carbon ironmaking technology. The main route to effectively reducing carbon emissions is to develop a gas-based direct reduction process and replace sintering with pelletizing, both of which focus on developing pelletizing technology. However,the challenge of pelletizing process development is to obtain high-quality iron concentrates. Consequently, the present paper also summarizes the development status of China’s mineral processing technology, including fine-grained mineral processing technology, magnetization roasting technology, and flotation collector application. This paper aims to provide a theoretical basis for the low-carbon development of China’s ISI in terms of a dressing–smelting combination.

碳酸酐酶1在非小细胞肺癌早期发病中作用机制的研究

目的:探讨碳酸酐酶1(carbonic anhydrase 1,CA1)在非小细胞肺癌(non-small cell lung cancer,NSCLC)早期诊断的价值及其在肺癌早期发病中的作用机制。方法:应用酶联免疫吸附实验检测临床NSCLC患者血清中CA1的含量;应用RNA干扰及质粒扩增的方法分别对A549、H520、H1299细胞进行处理,构建敲低和过表达CA1的细胞模型,并应用CCK-8法检测不同处理组中细胞的增殖情况;应用实时定量多聚酶链式反应(polymerase chain reaction,PCR)和Western blot方法检测WNT/β-catenin信号通路中关键信号分子Wnt3a和β-catenin mRNA和蛋白质的表达水平。结果:CA1在早期NSCLC患者的血清中表达水平显著高于健康人群。通过sh-RNA抑制CA1表达后,A549、H520和H1299细胞系的增殖速率显著降低,而过表达CA1后,细胞增殖速率明显提高。同时,CA1能够有效调节WNT/β-catenin信号通路中Wnt3a及β-catenin的表达水平。结论:CA1通过Wnt/β-catenin信号通路影响NSCLC的增殖过程;CA1有望成为NSCLC早期诊断的新型生物分子标记物。

Integration of preparation of K,Na-embedded activated carbon and reduction of Zn-bearing dusts

Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous reduction of zinc-bearing dusts and activation of low-rank coal was developed and its mechanism was clarified in this paper.Under the optimal conditions,the reduced zinc-bearing dusts containing low harmful elements(0.02%Zn,0.015%K and 0.03%Na)could be made as high-quality burden for blast furnace while the low-rank coal was transferred into K,Na-embedded activated carbon,which can be used as effective adsorbent for purification of SO_(2) and NO-containing flue gases.The solid wastes were successfully utilized to treat the flue gases through the process.The synergetic activation and reduction mechanism in the process was revealed.The coupling effect between reduction reactions of metal oxides in the dusts and activation reaction of carbon in the coal promoted the simultaneous reduction and activation process.In the meanwhile,part of the potassium and sodium from the zinc-bearing dusts could be adsorbed by the activated carbon and played a catalytic role in the activation process.