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Study of recycling blast furnace dust by magnetization roasting with straw charcoal as reductant

Ju Jinrong, Feng Yali, Li Haoran, Zhang Qian

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 149265

EN

Blast furnace dust generated in the iron-making process not only contains a large amount of iron but also the widely used non-ferrous metal zinc, which is classified as hazardous waste. In this study, the process of recycling blast furnace dust by magnetization roasting with straw charcoal as the reductant is proposed, and the mechanism of magnetization roasting was explored through thermodynamic analysis, X-ray diffraction analysis, and thermogravimetric analysis. The results for the thermodynamic analysis showed that the reduction of blast furnace dust by the straw charcoal was feasible theoretically. The increase in the roasting temperature not only promoted the reduction of hematite (Fe2O3) but also reduced zinc ferrite (ZnFe2O4) to Fe3O4 and ZnO. The results showed that almost all Fe2O3 and ZnFe2O4 in the blast furnace dust were reduced to Fe3O4 and ZnO under the conditions of straw charcoal amount of 6%, the roasting temperature of 750℃, and the roasting time of 60 min. Then, the iron concentrate with the iron recovery of 85.61% and an iron grade of 63.50% was obtained by the magnetic separation. Meanwhile, the grade of zinc in the iron concentrate was 0.19%. Finally, the flowsheet of simultaneously recovering iron and zinc from the blast furnace dust was put forward, which could realize that 85.61% of iron was recovered and 92.57% of zinc was extracted into the solution.

2

Comparison of packing media on stratified EPS and their role in the biofilm of trickling biofilter

Dong Bei, Zheng Jie, Wen Yi-Zheng, Lei Xian-Yan, Zhang Qian, Cao De-Ju

Environment Protection Engineering

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2021

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Vol. 47, nr 3

25--36

EN

The research focused on such packing media as ceramsite, polypropylene balls, and elastic fillers, and analyzed the main characteristics of extracellular polymeric substances (EPS) in their filter biofilms. The EPS were categorized as soluble EPS (S-EPS) and bound EPS (B-EPS). The component characteristics of stratified EPS were investigated via UV-Vis spectroscopy and a three-dimensional excitation-emission matrix (3D-EEM). The results showed that the EPS content of ceramsite biofilm was 245.2 mg/g VSS, which was higher than those of elastic filler material and polypropylene ball by 1.26 and 1.51 times, respectively. The protein (PN) and polysaccharide (PS) ratio of EPS in the ceramsite filter material was highest in S-EPS and B-EPS, indicating that the EPS have a stable structure. More than 67.58% of EPS formed by ceramsite was tightly bound EPS (TB-EPS), which was beneficial to maintaining the stability of biofilms. The levels of proteins (PN) and humic substances formed by ceramsite contained in the TB-EPS were higher than those of elastic filter material and polypropylene balls. 3D-EEM fluorescence spectra revealed that TB-EPS formed by a ceramsite contained high concentrations of tryptophan, tyrosine, and humic substances. The dehydrogenase activity of biofilm formed by ceramsite filler was higher than that formed by elastic fillers and polypropylene balls.

3

Dissolution kinetics of hemimorphite in methane sulfonic acid

Zhang Qian, Wen Shuming, Feng Qicheng, Nie Wenlin, Wu Dandan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

1--9

EN

Hemimorphite has a large content of zinc, but its recovery using flotation alone is low. Nowadays, hydrometallurgical and pyrometallurgical methods are used to treat zinc ores. In this work, the leaching and dissolution kinetics of hemimorphite by using methane sulfonic acid (MSA) as an alternative leaching reagent was investigated. The effects of several experimental parameters including reaction temperature, MSA concentration, particle size, and stirring speed were also analyzed. Results showed that zinc leaching increased with increased reaction temperature, MSA concentration, and stirring speed, as well as decreased particle size. The mechanism of hemimorphite dissolution in MSA solutions may be a new variant of the shrinking-core model. Based on experimental data and kinetics, the apparent activation energy was determined to be 49.50 kJ/mol. The rate of reaction equation was also obtained to describe the process and found that the MSA concentration largely influenced the leaching of hemimorphite.

4

Hydroxyl Terminated Polybutadiene: Chemical Modification and Application of these Modifiers in Propellants and Explosives

Zhang Qian, Shu Yuanjie, Liu Ning, Lu Xianming, Shu Yao, Wang Xiaochuan, Mo Hongchang, Xu Minghui

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 2

153--183

EN

Hydroxyl terminated polybutadiene (HTPB) as a telechelic liquid polymer has been widely used in propellants and explosives and many modified-HTPBs have been reported in the literature. As a binder or additive in propellants and explosives, the chemical modification of HTPB for improving certain properties of propellants has been summarized in detail in this article. According to the application drawbacks of HTPB, modified-HTPB can be classified differently. Furthermore, there are polymers that have been modified on their energetic properties, such as GAP-PB-GAP, BAMO-PB-BAMO, AMMO-PB-AMMO, Nitro-HTPB, HTPB-DNB and NHTPB. Pre-polymers modified on their combustion properties include Butacene®, FPDS-g-HTPB, Fc-HTPB, BiFc-g-HTPB, HTPB→[Fe(CO)3]x, PPA-HTPB-PPA and PNBE-HTPB-PNBE. HTPBs are also modified in curing systems containing, for example ETPB, PTPB, PrTPB, AzTPB, and PUPB, and other modification results are reviewed. Additionally, this overview is expected to provide an outlook for further studies in these fields.