Physical separation methods

All minerals in some way or the other are influenced by an external magnetic field although the degree of this response varies widely. Based on different response of different minerals in external magnetic field minerals have been classified into different groups that have essentially to development of an important physical separation method called magnetic separation which has been described quite in detail in the next chapter on mineral processing. Present topic is, therefore, not pursued any further. 

The physical separation methods find wide application in this industry because of the nature of the wastes. Centrifugation may be feasible in some applications, but it is not suitable for abrasive or very fine particles (less than 5 pm). 

The ilmenite production from heavy mineral sands exclusively utilizes a physical separation method using magnetic separation, gravity concentration and electrostatic separation. Flotation is practiced mainly for beneficiation of fine mineral sands containing rutile, ilmenite and zircon. The ilmenite that is produced in a number of operations in Western Australia, India and the USA is high in chromium, which makes the ilmenite unusable. This section discusses a new process that was developed for chromium removal from ilmenite concentrates. 

Physical separation methods can be based on equilibrium considerations, but the majority are not. Ordinary filtration is an example of a non-equilibrium, physical method and so is ordinary centrifugation— e.g.—the separation of a precipitate from the suspending liquid using an artificial gravity field. There are separation methods, which are called filtration which are not such as gel filtration. Ultracentrifugation in a salt gradient is a physical equilibrium method. 

Experiment 4 Practice of Gravimetric Analysis Using Physical Separation Methods... 

In general more independent physical constants that are sensitive to structure are needed when it is necessary to know more structural elements of a mixture. It will be clear that, dependent on the collected basic data, statistical methods for the analysis of mixtures in general only give a certain approach to their structures, but should never be considered as the ultimate purpose. Improvement of existing methods is imperative when new and more accurate data become available the development of various physical separation methods (distillation, chromatography, thermodiffusion, etc.) and of independent physical identification methods (ultraviolet and infrared spectra, mass spectrometry) may also contribute considerably to their perfection. 

First of all, a number of chromatographic and electrophoretic separation methods will be considered because in most cases unequivocal identification will be impossible without prior work-up of the dendrimer sample. The term chromatography refers collectively to physical separation methods by which mixtures of substances can be resolved into their various components by repeated equilibration between a stationary and a mobile phase. We shall now present a detailed consideration of the chromatographic techniques which can be used to solve separation problems in dendrimer chemistry. 

Nitrogen Enriched Air occurs as a colorless gas. It is produced from air in situ by physical separation methods. It contains not less than 90% and not more than 99% nitrogen, by volume. The remaining components are noble gases and, primarily, oxygen. 

Distillation and rectification are among the most common physical separation methods, both on a laboratory scale and for industrial production, which have encountered widespread application in the flavour and fragrance industry. It is the intent of the following discussion to familiarise the reader with the basic fundamentals necessary for the daily operation of such units extensive literature is available on the theoretical and practical aspects of designing and operating such equipment [1-9]. 

The question "Can chemistry be reduced to physics " is unclear. First, it is not clear how one would delineate and separate chemistry and physics—what, for example, about chemical physics or mechanical and physical separation methods in chemistry and chemical engineering Second, the question of reduction has to be made much more concrete. For example ... 

Gibbons D and Lambie DA (1971) Radiochemical methods of analysis. In WBson CL and WBson DW, eds. Comprehensive analytical chemistry, Vol 2C, Electrical methods, physical separation methods, pp. 130—205. Elsevier, Amsterdam. 

J.F.K. Huber, in C.L. Wilson and D.W. Wilson (Editors), Comprehensive Analytical Chemistry, Vol. II B, Physical Separation Methods, Elsevier, Amsterdam, 1968, p.41. 

Although simple and countercurrent (rectified) distillation are among the most important physical separating methods employed in chemical industry, and hence also in research and works laboratories, it is often found that the apparatus used for this purpose in the laboratory has a low efficiency by present-day standards. Furthermore, calculations on the process are seldom made instead, the work is as a rule based entirely on experience and empirical data. 

Wilson, C. L., Wilson, D. W., and Strouts C. R. N. 1968. Physical separation methods in Comprehensive Analytical Chemistry. Volume IIB. New York, NY Elsevier. 

The recovery of magnetic materials with physical separation methods is principally considered at this time for the following three products HDDs, air-conditioner compressors, and direct drive (DD) motors of laundry machines. In addition, efforts are underway in order to recycle relatively large magnets used in automobiles and industrial machines however, these are excluded from the discussion here because the methods involved do not typically employ mass separation but are rather individual, employing dismantling by hands with only some machine assistance. 

Membrane integration into the reaction environment ensures a first substantial hydrogen separation step (up to 90% of the hydrogen produced can be removed) as for CO2 separation, because of the higher carbon dioxide partial pressure in the reformer outlet stream, due to the hydrogen removal, physical separation methods could be used to separate CO2 rather than the chemical adsorption in mono-diethanol ammine (MDEA). 

The CO dean-up section typically consists of different units, usually a one- or two-stage WGS reactor, followed by aunit to remove the final traces of CO such as a selective oxidation (SELOX) - also called preferential oxidation (PrOx) unit, a methanation unit or a physical separation method (Pd-Ag-based membrane, PSA). It would often be desirable to eliminate the LT-WGS unit, as it constitutes a rather large-sized and heavy unit However, heat management restrictions and the still rather low efficiency of the PrOx unit require low GO concentrations in the feed. On the other hand, methanation would become more attractive once an enhanced selectivity permits conversion of CO without conversion of CO2, as this then no longer requires upstream CO2 separation. 

Ffowever, the physical separation method, needed to separate the CO2 from the hydrogen, uses an organic gas and requires high temperatures. 

For very high acid gas concentrations in the range of more than 25 vol%, physical separation methods might he able to offer a step ehange in the reduction of the complexity and costs of the proeessing line-tip. 

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