Solid/liquid separation flotation

Ovhemical DOSING for improvement of liquid-solid separation is traditionally designed and operated more or less independently of the geometry and hydraulic performance of the actual separation reactor. The widespread use of jar tests in the day-to-day operation of filtration and flotation plants illustrates this fact. Yet it is not difficult to visualize situations in which aggregation processes would furnish floes unsuitable for the subsequent separation unit, such as voluminous floes that do not settle out readily. 

Suspensions treated under conditions in which good floe formation exist are separated with higher efficiency in flotation units. For intermediary conditions of floe formation, sedimentation in well-designed tanks B and C and flotation tank D show comparable overall efficiency in liquid-solid separation. Flotation appears to be less favored than sedimentation if floe formation is accomplished by lower chemical dosages. 

The use of flotation for liquid-solid separation may compensate for some of these limitations of the sedimentation process for suspensions with less optimal floe formation. This effect was observed in particular if suspensions were coagulated with Al3+. 

Froth-flotation processes are used extensively for the separation of finely divided solids. Separation depends on differences in the surface properties of the materials. The particles are suspended in an aerated liquid (usually water), and air bubbles adhere preferentially to the particles of one component and bring them to the surface. Frothing agents are used so that the separated material is held on the surface as a froth and can be removed. 

Liquid-solid distributions are involved in ion-exchange and other adsorption-based separation processes, separation processes based on crystallization or precipitation, flotation processes for ore dressing, and smelting processes. 

Flotation is a solid-liquid separation process, that transfers solids to the liquid surface through attachment of gas bubbles to solid particles. Flotation processes are used in the processing of crushed ores, whereby a desired mineral is separated from the gangue or non-mineral containing material. Various applications in solid separation processes are also in use in waste treatment. 

A type of foam in which solid particles are also dispersed in the liquid (in addition to the gas bubbles), as in froth flotation. The solid particles can even be the stabilizing agent alternatively, the foam layer produced at the top of a separation vessel or distillation tower. The term sometimes refers simply to a concentrated foam, but this usage is not preferred. 

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... 

Solids separation from liquid is a common requirement in many industries. Typically used for the treatment of industrial and mimidpal wastes, and in mineral processing operations where water is used as the vehicle to grind and separate minerals via differential dissolution, precipitation, flotation or density. 

Flotation. Flotation is a gravity separation process which exploits differences in the surface properties of particles. Gas bubbles are generated in a liquid and become attached to solid particles or immiscible liquid droplets, causing the particles or droplets to rise to the surface. This is used to separate mixtures of solid-solid particles and liquid-liquid mixtures of finely divided immiscible droplets. It is an important technique in mineral processing, where it is used to separate different types of ore. 

When used to separate solid-solid mixtures, the material is ground to a particle size small enough to liberate particles of the chemical species to be recovered. The mixture of solid particles is then dispersed in the flotation medium, which is usually water. Gas bubbles become attached to the solid particles, thereby allowing them to float to the surface of the liquid. The solid partices are collected from the surface by an overflow weir or mechanical scraper. The separation of the solid particles depends on the different species having different surface properties such that one species is preferentially attached to the bubbles. A number of chemicals are added to the flotation medium to meet the various requirements of the flotation process ... 

The area of interest covered by this paper is limited to processes in which chemical conversion occurs, as in the processes noted above. Gas-liquid-particle processes in which a gaseous phase is created by the chemical reaction between a liquid and a solid (for example, the production of acetylene by the reaction between water and carbide) are excluded from the review. Also excluded are physical separation processes, such as flotation by gas-liquid-particle operation. Gas absorption in packed beds, another gas-liquid-particle operation, is not treated explicitly, although certain results for this operation must necessarily be referred to. 

Flotation is a gravity separation process that exploits the differences in the surface properties of particles. Gas bubbles are generated in a liquid and become attached to solid particles or immiscible liquid droplets, causing the particles... 

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