Thermodynamics of solid-liquid separation

FPS Institute, England and University of Pardubice, Czech Republic 

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Svarovsky, L., Thermodynamics of solid-liquid separation . Part H, Chapter 23, in Solid-Liquid Separation, 3rd edn, Ed. L. Svarovsky, Butterworths, London, 69n-10A (1990)... 

Particle-fluid interaction, thermodynamics of solid-liquid separation Part I—Particle-fluid interaction... 

Thirdly, there are those chapters which only needed minor updating and amendments. These include Characterization of Particles Suspended in Liquids, Efficiency of Separation of Particles from Fluids, Hydrocyclones, Separation by Centrifugal Sedimentation, Filtration Fundamentals, Methods for Limiting Cake Growth, Pressure Filtration, Particle-Huid Interaction, Thermodynamics of Solid-Liquid Separation. 

Here, Si, S2, S3 are the interfaces of solid-liquid 1, solid—liquid 2, and liquid 1-liquid 2, and v is the rate of separation. When cementing in water and oil products, the adhesive is liquid 1 and the medium is liquid 2. Equation (5.2) indicates that spontaneous wetting (without mechanical work to the interface) is possible when the surface tensions of the adhesive and the liquid are equal, i.e., for crad Hq = although the maximal value of (Tadliq is desirable because it is directly proportional to the adhesion thermodynamic work. 

The science of thermodynamics is widely used in systems involving heat or chemical change. This part of chapter 18 sets out to show that even in a cold, non-reacting system such as solid—liquid separation, thermodynamics can be very useful. The concepts of entropy and free energy can be used in ... 

In contrast to the above, very little use is made of thermodynamics of cold systems which do not involve flow of gases such as solid-liquid separation, yet the principles of thermodynamics underlie this subject too and can be made use of in practice. 

The thermodynamics of suspensions is a subject much neglected in textbooks, yet there are many potential uses, particularly in solid-liquid separation. A... 

Phase behavior 1n concentrated aqueous electrolyte systems is of interest for a variety of applications such as separation processes for complex salts, hydrometal 1urgical extraction of metals, interpretation of geological data and development of high energy density batteries. Our interest in developing simple thermodynamic correlations for concentrated salt systems was motivated by the need to interpret the complex solid-liquid equilibria which occur in the extraction of sodium nitrate from complex salt mixtures which occur in Northern Chile (Chilean saltpeter). However, we believe the thermodynamic approach can also be applied to other areas of technological interest. 

For the case in which phase II in Fig. 3 is a solid, it is not yet clear how the activities of the species Ox, Red, and C+ in the solid have to be defined on a strict thermodynamic basis, and how they could be determined. No experiments are known that would lead to a separation of the free energies of the equilibria la and Ib in the case of solids. When phase II is a solution phase, the activities of Ox, Red, and C+ are in principle accessible however, in that case also, it remains the problem that an extrather-modynamic assumption is necessary for quantifying the free energy of ion transfer between the liquid phases II and III. 

In most common chemical reactions, one or more of the reactants is in solution. Thus, an easy method to determine thermodynamic quantities of solution is desirable. Enthalpy of solution (heat of solution) is defined as the change in the quantity of heat which occurs due to a combination of a particular solute (gas, liquid, or solid) with a specified amount of solvent to form a solution. If the solution consists of two liquids, the enthalpy change upon mixing the separate liquids is called the heat of mixing. When additional solvent is added to the solution to form a solution of lower solute concentration, the heat effect is called the heat of dilution. The definitions of free energy of solution, entropy of solution, and so on follow the pattern of definitions above. 

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