Mineralization models treatment studies

In mineral processing, surface characterization techniques are used primarily to study mechanisms of various subprocesses. These studies are carried out mostly in research laboratories using model systems so as to keep the system simple and amenable to interpretation by known laws of physics and chemistry. For these very reasons, some of the newer surface characterization techniques have been used to investigate pure solids, often single crystals. In mineral processing operations, one necessarily deals with particles of complex ores with an objective to recover the valuable minerals contained in the ore. Experience, both in industry and laboratory, shows that complex ore particles behave differently from simple solids in many ways. In process evaluation and in optimization of operating plants, it is necessary to characterize the ore particles as they undergo various treatments. In recent years ESCA has been found to be a useful technique for... 

For an example of a careful analysis of an analogous situation with osteoporosis, see Hassager et al. (1994). These authors reviewed three published studies in which there were apparently considerable differences in response to hormone replacement therapy. By carefully modelling the effect of measurement error on bone mineral content they were able to show that it was plausible that patient-by-treatment interaction was much smaller than had been supposed and that nearly all patients benefitted from therapy. 

The processes of thermal decomposition play an important role in various practical fields including metallurgy, mineral conversion processes, pyrogenic chemical technology, pyrolysis and thermal treatment of wood and coal, com-hustion of natural and synthetical fuels, coal carbonization, the prevention of grain spontaneous ignition, and so on. There is still a need for scientifically well-founded approaches to control the thermal decomposition of materials. Many studies focus attention on the chemical transformations and reactions in the pyrolized systems and on the creation of mathematical models of such processes as the major parts of the theory of chemical decomposition of complex substances. 

Phenol is the most extensively studied adsorbate for the adsorption of aqueous solutions on carbon, for practical (in waste water treatment) as well as scientific reasons. It is also a good model compound for organic pollutants in wastewater. Numerous factors are known to have significant effects on the adsorption of phenol pH of solution, type of carbon, carbon surface functionalities, oxygen availability ( oxic vs. anoxic condition), mineral contents of carbon, and addition of electrolytes. Typical isotherms, as a function of solution pH, are shown in Figure 5.12. The amount adsorbed is decreased at both high and low pH values. 

In addition to spectra themselves, their treatment and, finally, the interpretation are the steps that lead to the information, which can be used in a surface complexation model. Interestingly, again with an arsenate iron(III) oxide mineral, the data treatment and the interpretation of XAS data by Waychunas et al. [44] have been assessed by Manceau [46]. For a nonspecialist in this technique, who is interested in the conclusions of the spectroscopic studies, such examples recommend a critical point of view. 

Yerramshetty, J.S., Lind, C., and Akkus, O. (2006) The compositional and physicochemical homogeneity of male femoral cortex increases after the sixth decade. Bone, 39 (6), 1236-1243. Donnelly, E. et al. (2010) Effects of tissue age on bone tissue material composition and nanomechanical properties in the rat cortex. J. Biomed. Mater. Res. A, 92 (3), 1048-1056. Donnelly, E. et al (2010) Contribution of mineral to bone structural behavior and tissue mechanical properties. Calcif. Tissue Int., 87 (5), 450—460. Pathak, S. et al (2012) Assessment of lamellar level properties in mouse bone utilizing a novel spherical nanoindentation data analysis method. J. Mech. Behav. Biomed. Mater., 13, 102—117. Burket, J.C. et al (2013) Variations in nanomechanical properties and tissue composition within trabeculae from an ovine model of osteoporosis and treatment. Bone, 52 (1), 326-336. Carden, A. et al (2003) Ultrastructural changes accompanying the mechanical deformation of bone tissue a Raman imaging study. Calcif. Tissue Int., 72 (2), 166-175. 

---