Showing 7 results for Ball Mill
M. Aazami, A. Khodadadi, A. Farzanegan,
Volume 4, Issue 3 (12-2007)
Abstract
Abstract: The specific rate of breakage is one of the most important factors in evaluation of
grinding process especially in ball mill. In this article the effect of ball size and feed size on
selection function were investigated using batch grinding circuit on two-iron ore anomaly (B, C)
from sangan mine in north of Iran. Eight different monosize fractions were prepared between 2000
and 500 microns, using a 2 sieve series. The specific rates of breakage (Si) were determined from
the size distributions at different grinding times, and the specific rates of breakage were compared
for three different ball diameters (25.4, 16.6 and 9.6 mm). The results showed that the breakage
function of both anomalies is normalizable (independent to the particle size) and it is independent
to the ball size. But the specific rate of breakage variate with feed size and ball size. Also optimum
size of balls for grinding of this feed obtained to be between 9.6-16.6mm.
A. H. Emami, M. Sh. Bafghi, J. Vahdati Khaki, A. Zakeri,
Volume 6, Issue 2 (6-2009)
Abstract
Abstract:
the changes of BET surface area of a mineral substance during intensive grinding process. Validity of the proposed
model was tested by the experiments performed using a natural chalcopyrite mineral as well as the published data. It
was shown that the model can predict the experimental results with a very good accuracy and can be used to predict
what may happen under the similar experimental conditions.
Based on experimental observations, a model has been developed to describe the effect of grinding time on
M. S. Saghian, R. Naghizadeh, H. Sarpoolaky,
Volume 10, Issue 2 (6-2013)
Abstract
In this study, the effect of different parameters such as time and temperature of calcination and milling on the formation of calcium aluminosilicates was investigated. Raw materials used in this study were calcium carbonate and kaolin in high purity. Powder X-ray diffraction patterns were obtained from all samples after heat treatment at various temperatures and times. To study the microstructure scanning electron microscope was used. Milling the samples contributed to the amorphous structure due to inducing defects in the structure. Moreover, increasing the milling time reduced crystallization temperature of anorthite. Uptake experiments were performed using solutions containing different concentrations of nickel. Samples were exposed to the solution for 24 h with stirring then the samples were filtered and the concentrations of the cations in the separated solutions were analyzed. FTIR analysis was conducted on the adsorbents before and after nickel uptake. Nevertheless, they hardly helped understand sorption mechanisms. Therefore, adsorption isotherms were studied instead. Three adsorption isotherms of Langmuir, Freundlich and DKR were used to model sorption data. Results suggested monolayer sorption occurs on the surface of the adsorbent and sorption energy calculated by DKR model was 22.36 kJ/mol which can be described as a strong chemical adsorption mechanism
A. Karimbeigi, A. Zakeri, A. Sadighzadeh,
Volume 10, Issue 3 (9-2013)
Abstract
Ni and Cu elemental powder mixtures containing 25, 50, and 75% at Cu were subjected to mechanical alloying in a planetary ball mill under various milling times. Structural evolution was analyzed by means of X-ray diffraction and scanning electron microscopy. Experimental results indicated that nanostructured solid solution alloy powders having homogeneous distribution of Ni and Cu were formed by milling-induced interdiffusion of the elements. Average crystallite size of the as-milled powders was decreased with increasing Ni content and milling duration, and found to be in the order of 15-40 nm after 30 h of milling for all powder compositions. Moreover, lattice parameter and lattice strain of solid solutions were increased with the time of MA, which was more intense for nickel-rich alloys
A. Yazdani, R. Zakeri,
Volume 12, Issue 2 (6-2015)
Abstract
In this paper, the possibility of mechanical coating of aluminum with either Ni or SiC using planetary ball
mill was studied. The Al substrate was fixed inside of the vial lid of a planetary ball mill filled with milling balls and
starting powder. The phase analysis and crystallite size measurement of the coatings were carried out using X-ray
diffraction (XRD) method. Scanning electron microscope (SEM) was employed to study the coating/substrate interface
and coating thickness. Hardness and wear resistance of coatings were also measured. The results indicated that all
coatings have relatively uniform thickness. SiC coating shows poor compaction and adhesion to the Al, while nanostructured Ni coating is well-bonded to the substrate. Moreover, Ni coating showed higher hardness and wear
resistance compared to SiC coating. It was found that the balls collision will result in the grain refinement of the
coating as well as Al substrate. Mechanically deposited Ni coating shows higher hardness value compared to those
obtained by conventional methods. This has been related to the induced grain refinement phenomenon.
Saeid Karimi, Akbar Heidarpour, Samad Ghasemi,
Volume 18, Issue 2 (6-2021)
Abstract
In this research, expanded graphite (EG) was successfully fabricated using a simple ball milling process followed by hydrofluoric (HF, 10 wt. %) leaching. The effects of ball milling time (0-15 h) and leaching time (1-24 h) on the exfoliation of graphite were examined by XRD and Raman spectra. Furthermore, the morphological evaluation of the obtained expanded graphite samples was carried out by scanning electron microscopy (SEM). The XRD results of the ball-milled and HF treated samples showed a slight peak shift and broadening of (002) plane for expanded graphite compared to the precursor and HF-treated samples. Moreover, the intensity of the (002) planes remarkably decreased by the ball milling process but remained constant after HF treatment. Raman spectra of the samples confirmed the ordering process only in HF-treated specimens. Moreover, the intensity ratio of 2D1 to 2D2 band gradually increased with enhancing the HF treatment time up to 5 hours, indicating a decrement in the number of graphite layers by leaching in the HF solution.
Abdur Rahman, Serajul Haque,
Volume 19, Issue 3 (9-2022)
Abstract
The effect of the milling time & ageing on the hardness, density, and wear characteristics of Al 7150 alloy specimens made via powder metallurgy has been studied. The different constituents of Al 7150 alloy were processed in a planetary ball milling set up with a BPR of 10:1 for 5 hours, 10 hours, and 20 hours. At 400 °C, the milled powders were subsequently hot compacted in a punch die setup. The hot-pressed specimens were solutionized initially, then aged artificially at 115 °C for 3, 6, 12, 24, 30, 45, 60, and 96 hours. The relative density was inversely proportional to the milling time. Microhardness tests showed a maximum VHN of 255 was measured for the 24 h aged T6 specimens produced from 20 h milled powders whereas the non-aged specimens, made from unmilled 7150 alloy powders showed a VHN of 40. However the samples showed a decline in microhardness beyond 24 h of ageing. Under various conditions of sliding distance and loading conditions, the samples subjected to T6 aging showed a reduced volumetric wear rate indicating the beneficial effect of artificial aging up to 24 hours. The volumetric wear rate gradually declined for the samples aged beyond 24 hours of aging. The HRTEM studies revealed a high density of uniformly scattered (MgZn2) precipitates in the base matrix, as well as (MgZn2) phases precipitating along grain boundaries. The presence of such second phase precipitates in the matrix improved the wear characteristics of the alloy matrix. The results showed that optimization of process parameters such as milling time, ageing as well as reducing the particle size of the base powders, the hardness and wear behavior of Al 7150 alloy may be improved.
