Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Froth structures

Overall there will be a concentration of the hydrophobic particles in the upper regions of the froth layer and a concentration of the hydrophilic particles in the lower regions. Figure 10.7 provides an illustration of how froth structure changes from the bottom to the top of the froth layer. At the very top of the froth bubble, coalescence and rupture will be occurring as well. The amount of ore that can be separated for any given amount of liquid is proportional to the surface area of the foam. It has been estimated that a foam with a specific surface area of 0.2 m2g-1 can separate a thousand times more ore, by mass, than the mass of its own liquid [629]. [Pg.254]

According to the model advanced in this review, the emulsion structure-related problems encountered in the treatment of diluted froths have their origin in elements of the original froth structure. [Pg.452]

Banford, A.W., Aktas, Z. and Woodburn, E.R., 1998, Interpretation of The Effect of Froth Structure on The Performance of Froth Flotation Using Image Analysis, Powder Technology, 98, 61-73. [Pg.610]

Figure 2.1. (a) Froth structure occurring during formation and drainage of foam in a column, (b) plateau borders, where tht capillary pressure sucks liquid into the borders... [Pg.25]

Weissenborn, P. and Pugh, R. J., Measurement of bubble size distribution in froths and its application to studying froth structures and stability, in Proceedings of the 12th Scandinavian Symposium on Surface Chemistry, Ste-nius, P. and Sarvaranta, L. (Eds), Department of Forestry Production, Helsinki University of Technology, Publication C6, Helsinki, 1994, pp. 152-154. [Pg.44]

A substance which assists in holding the foam structure produced by whipping or frothing in the manufacture of latex foam rubber. [Pg.29]

Your heartbeat increases in frequency and amplitude as you gaze at her skirt, the color of cool mint. In the froth, space doesn t have a definite structure. It has various probabilities for different shapes and curvatures. It might have a 60 percent chance of being in one shape, a 20 percent chance of being in another, and a 20 percent chance of being in a third form. Because any structure is possible inside the froth, we can... [Pg.65]

Structure. Foam structure is characterized by the wetness" of the system. Foams with arbitrarily large liquid to gas ratios can be generated by excessive agitation or by intentionally bubbling gas through a fluid. If the liquid content is sufficiently great, the foam consists of well-separated spherical bubbles thal rapidly rise upwards displacing the heavier liquid. Such a system is usually called a froth, nr bubbly liquid, rather than a foam. [Pg.662]

If there are sufficiently strong repulsive interactions, such as from Ihe electric double-layer lorce. then the gas bubbles at the lop of u froth collect together without bursting. Furthermore, their interfaces approach as closely as these repulsive forces allow typically on the order of 100 nm. Thus bubbles on top of a froth can pack together very closely and still allow most uf the liquid to escape downward under the influence of gravity while maintaining their spherical shape. Given sufficient liquid, such a foam can resemble the random close-packed structure formed by hard spheres. [Pg.662]

Other new materials are frothed or lightened syntactic plastics, which can be either isotropic 101 n0,111 132 —134.) or anisotropic 116). They have also been called integral (structural) syntactic foams and the smallest density obtained is 67 kg/m3 67). [Pg.92]

Three-layered structure. Van Sinderen, Wijn, and Zanting [Trans. IChemE, 81, Part A, p. 94 (January 2003)] postulate a tray dis-ersion consisting of a bottom liquid-rich layer where jets/bub-les form an intermediate liquid-continuous froth layer where bubbles erupt, generating drops and a top gas-continuous layer of drops. The intermediate layer that dampens the bubbles and... [Pg.27]

Foams, in the form of froths, are intimately involved and critical to the success of many mineral-separation processes (Chapter 10). Foams may also be applied or encountered at all stages in the petroleum recovery and processing industry (oil-well drilling, reservoir injection, oil-well production and process-plant foams). A class of enhanced oil recovery process involves injecting a gas in the form of a foam. Suitable foams can be formulated for injection with air/nitrogen, natural gas, carbon dioxide, or steam [3,5]. In a thermal process, when a steam foam contacts residual crude oil, there is a tendency to condense and create W/O emulsions. Or, in a non-thermal process, the foam may emulsify the oil itself (now as an O/W emulsion) which is then drawn up into the foam structure the oil droplets eventually penetrate the lamella surfaces, destroying the foam [3], See Chapter 11. [Pg.227]

Figure 6.12a shows the structure of the fluid mixture in a downcomer operated at low liquid rates with a nonfoaming mixture. At the upper (froth) zone of the downcomer, the vapor fraction is high and of the same order as in the tray froth. As the mixture travels downward, much of the vapor is disengaged. The froth zone transforms into an aerated liquid zone where vapor bubbles rise through a liquid pooL Upon further vapor disengagement, the aerated liquid zone transforms into a clear liquid zone. [Pg.284]

The velocity of sound in liquid froths was measured by Mallock,i and the theory developed. Emst found the. supersonic velocities in binary liquid mixtures peculiar a structure pattern develops. [Pg.66]

Crynes et al. [41] continued the study of Kim et al. [40]. The novel monolithic froth reactor, with a monolithic section 0.42 m long and 5 cm in diameter, was used. Cordierite monoliths with a cell density of 62 cells/cm were stacked, one on top of another, to provide a structure 0.33 m long. The monoliths, washcoated with 7-alumina and impregnated with CuO, were tested at 383-423 K and 0.48-1.65 MPa. The liquid flow rate was varied from 0.4 to 3.5 cm sec", and the gas flow rate ranged from 15.8 to 50 cm sec". Phenol in a concentration of 5000 ppm was typically oxidized with air. The reaction rate versus the liquid flow rate showed a distinct maximum of approximately 2 mol g"t sec" at about 1.7 cm sec", while the dependence of the reaction rate on the gas flow rate was rather weak, with a tendency to decrease as the flow rate increased. [Pg.258]

The surfactant used in the experiments was a polyethylen glycol ether of BASF company with the trade name Lutensol T03. General structure of the reagent is R0(CH2CH2 0)x H where R is iso-Cu H2 and x is 3,5,7,8,12.. The reagent has a nonionic character and does not give much froth in water. It was used as 500 g/t of solid material in the suspension. [Pg.575]


See other pages where Froth structures is mentioned: [Pg.383]    [Pg.259]    [Pg.435]    [Pg.442]    [Pg.444]    [Pg.647]    [Pg.404]    [Pg.405]    [Pg.407]    [Pg.605]    [Pg.383]    [Pg.259]    [Pg.435]    [Pg.442]    [Pg.444]    [Pg.647]    [Pg.404]    [Pg.405]    [Pg.407]    [Pg.605]    [Pg.196]    [Pg.594]    [Pg.216]    [Pg.63]    [Pg.31]    [Pg.529]    [Pg.618]    [Pg.1655]    [Pg.466]    [Pg.47]    [Pg.115]    [Pg.226]    [Pg.121]    [Pg.348]    [Pg.352]    [Pg.838]    [Pg.1158]    [Pg.308]    [Pg.426]    [Pg.427]    [Pg.258]    [Pg.239]   
See also in sourсe #XX -- [ Pg.438 , Pg.439 , Pg.440 , Pg.441 , Pg.442 , Pg.443 , Pg.444 , Pg.445 , Pg.446 , Pg.447 , Pg.448 , Pg.449 , Pg.450 , Pg.451 , Pg.452 ]




SEARCH



Froth

Frothing

© 2024 chempedia.info