Two-liquid flotation -

Leistner T, Mtiller M, Erler JV, Rudolph M, Peuker UA (2014) Selektive Trennung sehr feiner Partikelsysteme mittels Fllissig-Fliissig Rotation (Two Liquid Flotation). Chem Ing... 

The Lurgi gasifiers used by Sasol operate at "low" temperatures and consequently phenols, and "tars" are "distilled" from the coal at the top of the gasifier, and carried out with the raw gas. On condensation two liquid phases are formed, "tar" and "gas liquor" (water). The "tar acids" (phenol, cresols etc) are dissolved in the "gas liquor" which is fed to the Phenosolvan unit where the acids are recovered by counter current extraction with butyl acetate or diisopropyl ether. The crude tar acids are fractionated to yield phenol, ortho, meta and para cresol and xylenols. The phenol is further refined to produce a high purity, colourless and stable product. Phenol is used mainly in the production of formaldehyde resins while the cresols are used as flotation frothers and in the manufacture of pesticides etc. 

This experiment is another example of a step-growth polymerization, one that produces a crosslinked polymer. Two liquids are mixed, beginning the chemical reactions that cause polymerization and foam generation. The result is a hard polyurethane foam, similar to the material commonly used for insulation, for flotation in boats and canoes, and in furniture. This activity works well either as a laboratory experiment or as a demonstration. ... 

Not only for process (1) but in general the air-dissolved flotation is based on regularities described in preceding sections. The separation of floto-complexes of decimicron size from the liquid is necessary. Air-dissolved flotation can be used as the first stage of two-stage flotation. This two-stage microflotation is now used industrially. 

The density gradient in the column is obtained by mixing two liquids, one with a high density and one with u low density, with each other in defined quantities. Often aqueous inorganic solutions such as that of sodium bromide are used for polymers with densities p > 1 cmVg. The overall density (p) of a polymer sample can be obtained by measuring its flotation level. 

Sulfide ores are usually concentrated by mechanical upgrading and flotation processes at the mine. The nickel concentrate is then transported to the refinery for py-rometallurgical treatment j fter a roasting, to drive off part of the sulfur as sulfur dioxide SOj, the material is melted with a siliceous flux. This primary smelting forms two liquid phases, one a sihcate slag and one a sulfide phase, a low-grade matte, containing nickel and copper but also some iron. 

Two liquids Tendency of surfactant molecules to accumulate at gas-liquid interface and rise with air bubbles Removal of detergents from laundry wastes ore flotation 18, 20, 49-51... 

Some of the phenomena of differentiation of silicate rocks are probably to be treated as results of simple crystallization backed up by the effects of gravity in causing sinking or flotation of crystals. This is the only method of differentiation that has been experimentally proven, but the separation of two or more liquid phases, and perhaps other phenomena also, may take part in this little-known process. 

An iron deficiency could be accommodated by a defect structure in two ways either iron vacancies, giving the formula Fe] /D, or alternatively, there could be an excess of oxygen in interstitial positions, with the formula FeOi+ f. A comparison of the theoretical and measured densities of the crystal distinguishes between the alternatives. The easiest method of measuring the density of a crystal is the flotation method. Liquids of differing densities which dissolve in each other, are mixed together until a mixture is found that will just suspend the crystal so that it neither floats nor sinks. The density of that liquid mixture must then be the same as that of the crystal, and it can be found by weighing an accurately measured volume. 

Flotation. This is a means of separating a relatively small particle from a Liquid medium. The particle may have a specific gravity greater than, less than, or the same as the liquid from which it is floated. There are two fundamental requirements (1) a gas bubble and particle must come in contract with each other and (2) the particle should have an affinity for attaching itself to the bubhle. 

For the sepn of solids from liquids, there are two types of centrifuges a)Solid wall(such as imperforate basket type) centrifuge, in which sepn or concn is by subsidence or flotation and b)Perforated wall(such as perforated basket type) centrifuge in which the solid phase is supported on a permeable surface thru which the fluid passes. A 3rd type is a combination of a) b) above. Here the primary concn is achieved by subsidence, followed by drainage of die liquid phase from the solid phase. These centrifuges can be either of batch or continuous operations. For sepn of liquids, there are bottle and tubular centrifiiges(Ref 2, 8,10,12,14,16,19,20,21,23,25,26 27)... 

Gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are widely used in the chemical and petrochemical industries for processes such as methanol synthesis, coal liquefaction, Fischer-Tropsch synthesis and separation methods such as solvent extraction and particle/gas flotation. The hydrodynamic behavior of gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are of great importance for the design and scale-up of reactors. Although the hydrodynamics of the bubble and slurry bubble columns has been a subject of intensive research through experiments and computations, the flow structure quantification of complex multi-phase flows are still not well understood, especially in the three-dimensional region. In bubble and slurry bubble columns, the presence of gas bubbles plays an important role to induce appreciable liquid/solids mixing as well as mass transfer. The flows within these systems are divided into two... 

This example is divided into three parts. In (a), the development of a new, selfaspirating and radially discharging funnel-shaped nozzle is presented. In (b), a flotation cell with two spatially separated spaces is described. The inner chamber is used for contacting gas bubbles with flocks and the annular ring around it is needed for the tranquilization of liquid throughput. This facilitates the complete separation of the flocks from the biologically purified waste water. It is shown how the flotation kinetics can be determined in this continuously run cell and how this knowledge is used to scale-up a full-scale flotation plant. On the contrary, in (c), data from batch-wise performed experiments are used to evaluate the flotation kinetics and to scale-up continuously run full-scale flotation cells. 

Foamed emulsions are disperse systems with two disperse phases (gas and liquid) in the disperse medium (surfactant solution). Water foamed emulsions are formed when foams or aqueous surfactant solutions are used to clean up oil deteriorated surfaces, in the process of oil flotation of waste waters, in firefighting when the foam contacts various organic liquids and in the processes of chemical defoaming (foam destruction by antifoams). Individual foamed emulsions can have practical importance e.g. a foamed emulsion of bitumen is used in road coating foamed emulsions from liquid fuels are used as explosives. 

According to the collection procedure for the enriched gas-liquid and/or gas-solid interfaces, adsorptive bubble separation processes or techniques can also be divided into two large categories (a) foam separation, which involves the production of foam in the process, and (b) nonfoaming adsorptive bubble separation, which involves no production of foam. Foam separation can be further subdivide into foam fractionation and flotation. Nonfoaming adsorptive bubble separation, however, can be further subdivided into bubble fractionation, solvent sublation, and noirfoaming flotation. Lemlich (84) and Wang (1,75) provided the definitions of these technical terms in their books. 

Flotation is the term used to describe a process in which the species being separated from the bulk liquid media are insoluble particulates. Froth flotation is another one of the two foam separation processes. It also involves the production of foam in a heterogeneous aqueous system, and has a great deal of potential for the water and wastewater treatment. Froth flotation can be subdivided into at least seven categories (42,43,84), including precipitate flotation, ion flotation, molecular flotation, microflotafion, adsorption flotation, ore flotation, macroflotation, and adsorbing colloid flotation. They are described separately below. 

Type of flow pattern(s) involved in an adsorptive bubble separation system depends on the type of process used. For example, bubble fractionation involves two-phase (gas-phase and liquid-phase) bubble flow, while solvent sublation involves multiphase bubble flow in their vertical bubble cells. Foam fractionation involves a two-phase bubble flow in the bottom bubble cell, and a two-phase froth flow in the top foam cell. However, all froth flotation processes (i.e., precipitate flotation, ion flotation, molecular flotation, ore flotation, microflotation, adsorption flotation, macroflotation, and adsorbing colloid flotation) involve multiphase bubble flow and multiphase froth flow. 

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