of galena activated mechanically in planetary centrifugal mill were studied.
A dual cell system was introduced to investigate the leaching process. The
experimental results indicated that the mechanical activation improved the
galena’s lattice constant, the lattice distortion and the degree of
crystal defect, which resulted a decreasing of initial potential of galena
electrode and an increasing of output voltage of the leaching cell.
The changes in specific surface area and structure disorder of mechanically activated arsenopyrite were investigated. The
rate of nonoxidative decomposition of mechanically activated arsenopyrite was increased almost 10-times when compared with
nonoxidative decomposition of a non-activated sample. An empirical linear relationship was found (r=0.996) between the rate constant of decomposition and the ratio of specific surface to transmission of the absorption band
of arsenopyrite at
Authors:K. Wieczorek-Ciurowa, K. Gamrat, and Ju. Shirokov
A catalytic action of the mechanochemical products of copper hydroxocarbonate with calcium carbonate was investigated in n-butyl
alcohol oxidation tests. The solid products of high-energy milling were identified using thermogravimetry supplemented by
X-ray diffraction method. It was shown that the mechanical activation induces more effective tested catalyst because it promotes
the alcohol conversion at lower temperatures than that unmilled one.
In this paper the reduction of lead and zinc sulphide by hydrogen is described. It has been found that the rate of formation
of elemental lead or zinc is favourably affected by mechanical activation of PbS and ZnS produced by intensive grinding. This
effect was observed in the region 678–1048 K for galena and in the region 851–1023 K for sphalerite. It has appeared that
disordering in the structure of both minerals results in the decrease in experimental activation energy.
The reduction of cinnabar (HgS) and stibnite (Sb2S3) by hydrogen was investigated. These investigations were performed in the temperature region 636–765 K for cinnabar and in the region 825–954 K for stibnite. It has appeared that the mechanical activation positively affects the thermal reduction of the sulphides. The thermal decomposition of HgS is accompanied by a change in mechanism taking place at 744 K. As to Sb2S3, the change in mechanism inthe investigated temperature region was not observed.
Authors:K. Wieczorek-Ciurowa, Ju. Shirokov, M. Paryło, and K. Gamrat
The chemical and physical processes occurring during grinding of copper hydroxocarbonates mixtures with aluminium were studied.
A planetary ball mill was used. A thermogravimetry and X-ray powder diffraction method allowed to determine the composition
of solid products after mechanical activation. The amount of the Cu2(OH)2CO3 undecomposed andAl2O3⋅3H2O, CuO, Al2O3, Cu0, CuxAly alloys and remained Al0 in the systems is strongly dependent on the duration of grinding and on the proportion of components.
The comparative results are presented.
Authors:Seval Koç, Nil Toplan, Kenan Yildiz, and H. Özkan Toplan
amount of the glass phase is detrimental to the mechanical properties of the mullite that is prepared from kaolinite [ 7 ].
Mechanicalactivation of the starting materials is a promising method for the precursor's preparation. Particle size
Authors:Eda Elmas, Kenan Yildiz, Nil Toplan, and H. Özkan Toplan
(e.g., vibratory, oscillating, or planetary milled) [ 12 ]. Mechanicalactivation, which results in reduced crystalline size and induces residual stress to the particles, is responsible for such a phenomenon. In some cases, chemical reactions may
Authors:K. Wieczorek-Ciurowa, K. Gamrat, M. Paryło, and Ju. Shirokov
The physical mixtures of hydroxocarbonates of Cu and Ni with aluminium were activated using a laboratory planetary mill. The
chemical reactions and alloy formations as the effects of grinding were followed by the phase analysis of solid products based
on the thermogravimetry and X-ray diffractometry. Experimental evidence indicates that the nature of reactions and products
of mechanical activation was dependent on the amount of aluminium and time of grinding.
use of mechano-chemistry for production of glass, glass–ceramics, and other glass-derived materials. The polymeric structure of glasses allows one to expect that mechanicalactivation will have an effect on the thermal transformations of glasses