scholarly journals Effect of Physical and Mechanical Activation on the Physicochemical Structure of Coal-Based Activated Carbons for SO2 Adsorption

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 707 ◽  
Author(s):  
Liu ◽  
Hao ◽  
Zhao ◽  
Su ◽  
Feng ◽  
...  
Keyword(s):  
Mechanical Activation ◽  
Ball Milling ◽  
Oxygen Content ◽  
Milling Time ◽  
Activated Carbons ◽  
Defective Structure ◽  
Dry Ice ◽  
So2 Adsorption ◽  
Physicochemical Structure ◽  
Ball Milling Time

The SO2 adsorption efficiency of activated carbons (ACs) is clearly dependent on its physicochemical structure. Related to this, the effect of physical and mechanical activation on the physicochemical structure of coal-based ACs has been investigated in this work. In the stage of CO2 activation, the rapid decrease of the defective structure and the growth of aromatic layers accompanied by the dehydrogenation of aromatic rings result in the ordered conversion of the microstructure and severe carbon losses on the surfaces of Char-PA, while the oxygen content of Char-PA, including C=O (39.6%), C–O (27.3%), O–C=O (18.4%) and chemisorbed O (or H2O) (14.7%), is increased to 4.03%. Char-PA presents a relatively low SBET value (414.78 m2/g) owing to the high value of Non-Vmic (58.33%). In the subsequent mechanical activation from 12 to 48 h under N2 and dry ice, the strong mechanical collision caused by ball-milling can destroy the closely arranged crystalline layers and the collapse of mesopores and macropores, resulting in the disordered conversion of the microstructure and the formation of a defective structure, and a sustained increase in the SBET value from 715.89 to 1259.74 m2/g can be found with the prolonging of the ball-milling time. There is a gradual increase in the oxygen content from 6.79 to 9.48% for Char-PA-CO2-12/48 obtained by ball-milling under CO2. Remarkably, the varieties of physicochemical parameters of Char-PA-CO2-12/48 are more obvious than those of Char-PA-N2-12/48 under the same ball-milling time, which is related to the stronger solid-gas reactions caused by the mechanical collision under dry ice. Finally, the results of the SO2 adsorption test of typical samples indicate that Char-PA-CO2-48 with a desirable physicochemical structure can maintain 100% efficiency within 30 min and that its SO2 adsorption capacity can reach 138.5 mg/g at the end of the experiment. After the 10th cycle of thermal regeneration, Char-PA-CO2-48 still has a strong adsorptive capacity (81.2 mg/g).

A New Technology of Producing Fe-TiC Powder by Mechanical Activation-Reductive Diffusion

2011 ◽  
Vol 199-200 ◽  
pp. 1813-1818
Author(s):  
Wei Li ◽  
Kang Sun
Keyword(s):  
Mechanical Activation ◽  
Ball Milling ◽  
Milling Time ◽  
New Technology ◽  
Time Intervals ◽  
Mixed Powder ◽  
Cost Efficient ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Ball Milling Time

A lower-temperature and cost-efficient way is developed to produce Fe-TiC powders. Fe-TiC is produced by means of mechanical activation -reductive diffusion with ilmenite and graphite. The feasibility of this method and the kinetics of the carbothermic reduction are studied with both natural ilmenite and synthetic ilmenite, respectively. The result approved that Fe-TiC powder could be produced by this new technique; moreover, the particles were prominently diminished in size and activated after ball milling. No obvious reactions were detected when ball milling time was less than 8h by EPMA and XRD; however, the mixed powder of Fe and TiC was obtained after annealing for different time intervals. The kinetic study showed that the apparent activation energy of the reductive reaction decreased gradually with milling time due to mechanical activation, but this effect weakened after ball milling for 6h. As ascertained experimentally, the optimum ball milling time was between 4h and 6h.

Experimental Investigation and Micro-Structural Evolution Analysis of CNT & Fly Ash Reinforced Aluminium Matrix Composites

2015 ◽  
Vol 830-831 ◽  
pp. 429-432 ◽  
Author(s):  
Udaya ◽  
Peter Fernandes
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Fly Ash ◽  
Ball Milling ◽  
Milling Time ◽  
Structural Evolution ◽  
Matrix Composites ◽  
Evolution Analysis ◽  
Ball Milling Time ◽  
Al Matrix

The paper illustrates Carbon nanotubes reinforced pure Al (CNT/Al) composites and fly ash reinforced pure Al (FA/Al) composites produced by ball-milling and sintering. Microstructures of the fabricated composite were examined and the mechanical properties of the composites were tested and analysed. It was indicated that the CNTs and fly ash were uniformly dispersed into the Al matrix as ball-milling time increased with increase in hardness.

Preparation of High Density BaZr0.97Y0.03O3-δ Ceramic and its Interaction with Titanium Melt

2018 ◽  
Vol 768 ◽  
pp. 261-266 ◽  
Author(s):  
Ju Yun Kang ◽  
Guang Yao Chen ◽  
Bao Tong Li ◽  
Zi Wei Qin ◽  
Xiong Gang Lu ◽  
...  
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Milling Time ◽  
Sintered Pellet ◽  
Conventional Solid State Reaction ◽  
Industrial Grade ◽  
Minimum Particle Size ◽  
Ni Alloy ◽  
Improved Stability ◽  
Ball Milling Time

In this paper, the BaZrO3(BZ) and BaZr0.97Y0.03O3-δ(BZY3) powders were prepared by using the industrial grade BaCO3, ZrO2and Y2O3powders combining the conventional solid state reaction. The BaZrO3(BZ) and BaZr0.97Y0.03O3-δ(BZY3) ceramics were fabricated at 1750°C. The effect of ball milling time and sintering aid (TiO2) on the sinterability of BaZr0.97Y0.03O3-δ(BZY3) ceramics were investigated, and the improved stability of BaZrO3refractory with Y2O3additive were studied according to the refractory-metal interaction. The results revealed that the particle size of BZY3 powders decreased first and then increased with the increasing of ball milling time from 6h to 12h, and the minimum particle size was only 2.252μm at 8h. When 2wt.%TiO2was added, the sintered pellet of BZY3 was the most densest and the relative density was above 95%. After melting the Ti2Ni alloy on the BZY and BZ ceramics, the thickness erosion layer of BaZrO3and BZY3refractories and Ti2Ni alloy is approximately 50μm and 20μm respectively, showing that BZY3 was more stable than BaZrO3refractory.

scholarly journals Effects of Mechanical Ball Milling Time on the Microstructure and Mechanical Properties of Mo2NiB2-Ni Cermets

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1926 ◽  
Author(s):  
Lei Zhang ◽  
Zhifu Huang ◽  
Yangzhen Liu ◽  
Yupeng Shen ◽  
Kemin Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ball Milling ◽  
Milling Time ◽  
Bending Strength ◽  
Volume Fraction ◽  
Milling Process ◽  
Microstructure And Mechanical Properties ◽  
Mechanical Ball Milling ◽  
Ball Milling Time ◽  
Milled Powders

Mo2NiB2-Ni cermets have been extensively investigated due to their outstanding properties. However, studies have not systematically examined the effect of the powder milling process on the cermets. In this study, Mo, Ni, and B raw powders were subjected to mechanical ball milling from 1 h to 15 h. XRD patterns of the milled powders confirmed that a new phase was not observed at milling times of 1 h to 15 h. With the increase in the mechanical ball milling time from 1 h to 11 h, raw powders were crushed to small fragments, in addition to a more uniform distribution, and with the increase in the mechanical ball milling time to greater than 11 h, milled powders changed slightly. Mo2NiB2-Ni cermets were fabricated by reaction boronizing sintering using the milled powders at different ball milling times. The milling time significantly affected the microstructure and mechanical properties of Mo2NiB2-Ni cermets. Moreover, the Mo2NiB2 cermet powder subjected to a milling time of 11 h exhibited the finest crystal size and the maximum volume fraction of the Mo2NiB2 hard phase. Furthermore, the cermets with a milling time of 11 h exhibited a maximum hardness and bending strength of 87.6 HRA and 1367.3 MPa, respectively.

Preparation and Characterization of Coated Alumina/Aluminum Cermet Composite Powder via Ball Milling Method

2020 ◽  
Vol 861 ◽  
pp. 250-255
Author(s):  
Fang Wang ◽  
Ai Xia Chen ◽  
Chao Yang ◽  
Min Han Xu ◽  
Da Ming Du ◽  
...  
Keyword(s):  
Ball Milling ◽  
Aluminum Powder ◽  
Composite Powder ◽  
Milling Time ◽  
Ceramic Materials ◽  
Aluminum Composite ◽  
Alumina Particles ◽  
Milling Method ◽  
Milling Condition ◽  
Ball Milling Time

Cermet is an important new engineering material that not only maintains the excellent properties of ceramic materials, but also has the advantages of metal materials. In this paper, the encapsulated alumina-aluminum composite powder was prepared by ball milling and characterized, which laid a foundation for the development of high properties cermet materials. Through the analysis of experimental results, the conclusions are shown when the ball milling time is greater than 3 h, the alumina particles are more evenly distributed around the aluminum powder. the ball milling for 6 h may have reached a limit of the mixing uniformity of the two powder, so the ball milling is determined 6 h as the better ball milling time. Under the ball milling condition of 50 r/min, the distribution of alumina particles around the aluminum powder is more uniform around the aluminum powder than the ball mill under 75 r/min, the ball milling speed is preferably 50 r/min. As the content of aluminum powder increases, the distribution of alumina in aluminum powder is large and uniform, and there is a small amount of pinning. It provides a package-like composite for the preparation of cermet with a wrapped structure and the thermal conduction mechanism of the controlled cermet.

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