PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2024
·
IF 6.9
Qiang Wang,Chun-guang Song,Hai-qing Hao,Meng Wang,Zong-yu Feng,Yong-qi Zhang,Xiang-xin Xue,Xiao-wei Huang
Wastewater recycling is the desired goal of the rare earth separation plants for current ecological requirements and economic benefit. The MgCl 2 wastewater generated during rare earth extraction and separation process was treated by spray pyrolysis for the first time to achieve full recycling. The kinetic of spray pyrolysis process and the mechanism affecting the activity of MgO powder were investigated. The results showed that the rate determining step of MgCl 2 solution spray pyrolysis was transformed from a chemical reaction control to a diffusion process control after the temperature exceeded 1073 K. The MgO powder prepared by spray pyrolysis was rough and porous, the embedding of Cl made MgO grains severely distorted, producing more defects. Meanwhile, polycrystalline basic magnesium chloride likewise had more defects. These two points resulted a higher density of defects of MgO powders, and causing higher activity. Moreover, at a temperature of 1173 K, MgCl 2 concentration of 300 g/L and N 2 flow rate of 40 L/min, the thermal decomposition rate of MgCl 2 reached 99.54%, the alkalinity of the powder reached 0.045 mol/g, and the iodine absorption value reached 102.72 mg I 2 /g MgO. Meanwhile, the high purity hydrochloric acid with a concentration of 6.70 mol/L was obtained.
研究领域:
环境科学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE FORUM
·
2014
·
IF 0
Lu Liu,Hui Ren,Qing Jie Jiao
Due to high reaction activity and high combustion heat release, magnesium is widely used in the field of explosives. The research focus of this article is the effect of magnesium powder size and content on the thermal decomposition of PTFE. Two different particle sizes of magnesium powder are regarded as research objects. The thermal behavior of Mg/PTFE energetic system was investigated by TG-DSC analyzer. The experimental results show that magnesium has a catalytic effect on the thermal decomposition of PTFE. With the increase of magnesium content , the decomposition peak temperature of PTFE decreased firstly and when passed the ratio 50% increased, the best mixing ratio is Mg: PTFE =50:50. Within nanopowder, the activation energy of PTFE decreased by 150kJ∙mol-1 compared to 112 kJ∙mol-1 by mixing with micro powder. Obviously nanopowder has a better reactivity than micro powder, so has a more obvious catalytic effect.
研究领域:
材料科学
·
热力学
✓ 已验证
DOI
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2013
·Vol. 51
·期 16
·3328-3332
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IF 3.543
Hou Chen,Gaojian Lv,Ying Liang,Jinming Sun
High performance polyacrylonitrile (PAN) was prepared with Mg powder as both reducing agent (RA) and supplemental activator (SA) by single electron transfer-living radical polymerization (RASA SET-LRP). First-order kinetics of polymerization with respect to monomer concentration, linear increase of molecular weight, and narrow polydispersity with monomer conversion, and the obtained high isotacticity PAN indicate that RASA SET-LRP in the presence of Mg powder could simultaneously control molecular weight and tacticity of PAN. compared with that obtained with ascorbic acid (VC) as RA, an obvious increase in isotacticity of PAN was observed. the block copolymer pan- b -pAN with molecular weight at 112,460, polydispersity at 1.33, and isotacticity at 0.314 was successfully prepared. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51 , 3328–3332
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2025
·
IF 6.2
Dongyang Qiu,Mohammad Zaid Kamil,Mohammad Alauddin,Lijuan Liu,Xianfeng Chen,Chuyuan Huang,Paul Amyotte
Magnesium (Mg) dust in metal processing and energy settings exhibits high explosion sensitivity and strong destructiveness, readily triggering cascading accidents. To precisely control this risk, this study mechanochemically prepared montmorillonite (MMT) and ammonium polyphosphate (APP) composite inhibitors, established a vertical combustion duct platform, evaluated its suppression efficacy for Mg dust explosions, and combined residue characterization, thermal analysis, and Chemkin simulations to elucidate the synergistic suppression mechanism. The MMT/APP composite outperformed single components; at an inerting ratio (α) = 1.25, the 1:1 formulation fragmented the flame, prevented the formation of a continuous front, and self-extinguished at mid-duct. Relative to pure Mg dust, the maximum flame velocity ( V max ) decreased by 91.5%; the peak flame front pressure ( P max ) and the maximum rate of pressure rise (( dP / dt ) max ) were reduced by 97.6% and 98.0%, respectively; and the peak temperature ( T p ) fell to 236°C. Mechanistically, MMT provides endothermy alongside heat and mass transfer shielding. At elevated temperature, MMT forms refractory SiO 2 and Al 2 O 3 phases and lamellae that suppress O 2 diffusion and interparticle heat conduction. Gas phase reaction kinetics simulations indicate that APP decomposes endothermically to generate nitrogen and phosphorus-containing intermediates that markedly deplete the O radical, manifested as rapid chain termination along the nitrogen pathway and sustained suppression along the phosphorus pathway. This study provides quantitative guidance for the formulation of efficient Mg dust inhibitors and supports improvements in the inherent safety of Mg processing.
研究领域:
安全工程
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材料科学
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化学工程
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燃烧学
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工业安全
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热力学
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反应动力学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）