Investigation on Crushing Kinetic Equation of Ball Milling of Quartz Powder

2010 ◽  
Vol 156-157 ◽  
pp. 812-816 ◽  
Author(s):  
Shu Xian Liu ◽  
Li Li Shen ◽  
Qian Ping Wang ◽  
Fu Sheng Niu

The kinetic equation of ball milling of quartz powder was deducted. by grinding quartz experiments in a intermittent ball mill. The results showed that: (1) Conventional first-order kinetic equation which describe the velocity of quartz grinding is not concordant with theory. Dynamics parameters are not constant, but time-related. (2) The kinetic equation of time correction can more clearly express their grinding speed. Fitted regression equation has a more accuracy prediction for the instantaneous concentration of particle size, and obtain the dynamics constants. (3) The grinding speed has a maximum value over time because of the particle size distribution and grading comminution. (4).The time index is not only related with the material nature and conditions of the grinding, but also with the particle size distribution. To predict accurately, the grade range should be narrow. (5). Different grinding time distribution of particles in the ball mill should be measured in the continuous grinding process. The comminution results can be predicted by the kinetic equation mentioned above.

2017 ◽  
Vol 898 ◽  
pp. 1717-1723 ◽  
Author(s):  
Xue Mei Yi ◽  
Shota Suzuki ◽  
Xiong Zhang Liu ◽  
Ran Guo ◽  
Tomohiro Akiyama

Combustion synthesis (CS) of β-SiAlON was conducted using a 3D ball mill, with a focus on the effect of the 2D/3D ball mill premixing conditions on the CS raw material particle size as well as on the yield and grain shape of the final products. The results showed that the particle size distribution of the raw materials was significantly affected by the premixing conditions. Various particle sizes and particle size distributions could easily be obtained by using a 3D mill instead of a 2D mill due to the complex biaxial rotation movement of 3D milling. The particle size was more sensitive to the rotation ratio (vertical spin/horizontal spin, Vv/Vh) than the rotation rate when using 3D milling. Finally, β-SiAlON with less than 5 mass% unreacted Si was obtained using premix milling conditions of 135×200 [vertical spin (rpm) × horizontal spin (rpm)]. The grain shapes of the final products were clearly influenced by the particle size distribution of the raw mixtures.


2018 ◽  
Author(s):  
Isaac Capone ◽  
Kevin Hurlbutt ◽  
Andrew Naylor ◽  
Albert Xiao ◽  
Mauro Pasta

Sodium-ion batteries will have an important role as a complement to lithium-ion in a future where lithium or cobalt, two critical elements for lithium-ion batteries, become scarce or prohibitively expensive. Red phosphorus (RP) is a promising candidate as an anode for sodium-ion batteries because of its low potential and high specific capacity. Its main disadvantage is its 490% volumetric expansion during sodiation. This leads to particle pulverization and substantial reduction of the cycle life. Furthermore, RP has an extremely low electronic conductivity of 10<sup>-14</sup> S cm<sup>-1</sup>. Both issues have been previously addressed by ball milling RP with a carbon matrix. This decreases the RP particle size and also forms a more electronically conductive composite. However, it is challenging to determine the RP particle size independent of the size of the composite particles. Consequently, little is known about how much the RP particle size must be reduced to improve anode performance. Here we quantify the relationship between the RP particle-size distribution and its cycle life for the first time by separating the ball milling process into two steps. An initial wet ball milling is used to control the RP particle-size distribution, which is measured via dynamic light scattering. This is followed by a dry milling step to produce RP-graphite composites. We found that wet milling breaks apart the largest RP particles in the range of 2 to 10 µm decreases the Dv90 from 1.85 to 1.26 µm and significantly increases the cycle life of the RP. Furthermore, we determined that the length of time of the second milling step affects the uniformity of the carbon distribution in the composite. Photoelectron spectroscopy and transmission electron microscopy confirms the successful formation of a carbon coating, thus improving the performance of the resulting material. The RP with a Dv90 of 0.79 µm mixed with graphite for 48h delivered 1,354 mA h g<sup>-1</sup> with high coulombic efficiency (>99%) and cyclability (88% capacity retention after 100 cycles). These results are an important step in the development of cyclable, high-capacity anodes for sodium-ion batteries.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5861
Author(s):  
Giannin Mosoarca ◽  
Cosmin Vancea ◽  
Simona Popa ◽  
Sorina Boran

A new natural adsorbent material, Bathurst burr powder, was used to remove crystal violet dye from synthetic wastewaters. Particle size distribution and SEM and FTIR analyses were performed to characterize it. The effect of the operational adsorption process parameters (pH, ionic strength, initial dye concentration, adsorbent dose, contact time, temperature) onto the adsorption process was evaluated in a batch system. Equilibrium, kinetic, and thermodynamic studies were performed in order to understand the adsorption process. Taguchi method and ANOVA test were used to optimize the dye adsorption conditions and to establish the percentage contribution of each factor, respectively. The accuracy of the Taguchi prediction method was analyzed by correlating the predicted dye removal efficiency with the experimentally determined one. The particle size distribution analysis showed that 82.15% of the adsorbent particles have an average size below 0.5 mm. The adsorption process followed the Langmuir isotherm and pseudo-second order kinetic model. Maximum adsorption capacity value (164.10 mg·g−1) was higher compared to many similar adsorbents. The process was endothermic, spontaneous, and favorably involving a physisorption mechanism. The Taguchi method showed that the most influential controllable factor was pH (65% contribution in adsorption efficiency) and the data analysis indicates a very good accuracy of the experimental design (R2 = 0.994). The obtained results demonstrated that Bathurst burr powder can be used as a cheap and efficient adsorbent for crystal violet dye removal from aqueous solution.


2015 ◽  
Vol 816 ◽  
pp. 15-20
Author(s):  
Qian Yu ◽  
Mei Hui Song ◽  
Yan Li ◽  
Xiao Chen Zhang

AlN/Cu composite powder was prepared by ball milling method. Laser particle size analyzer, X-ray diffraction and scanning electron microscopy analysis were performed to study AlN/Cu composite powders. The effects of rotation speed, mixing time, and ball to powder weight ratio (BPR) on the particle size distribution, composition, and morphology were investigated. Results showed that the best ball milling parameters were the rotation speed of 200r/min, mixing time of 6 hours and BPR 10:1. In this best condition, AlN/Cu composite powders would be obtained with optimum particle size distribution and morphology. Then composite powders were pressed at 500MPa and sintered at 1000°C in N2atmosphere. Finally, the composite with an AlN content of 33wt% showed the bending strength of 370MPa, Vikers hardness HV154, thermal conductivity of 182.7W/m°C and electrical conductivity of 3.08MS/m. However, the composite with an AlN content of 25wt% showed the bending strength of 329MPa, Vikers hardness HV122, thermal conductivity of 195W/m°C and electrical conductivity of 6.54MS/m.


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