Percolators batch

Batch Percolators The batch tank is not unlike a big nutsche filter it is a large circiilar or rectangiilar tank with a false bottom. The solids to be leached are dumped into the tank to a uniform depth. They are sprayed with solvent until their solute content is reduced to an economic minimum and are then excavated. Countercurrent flow of the solvent through a series of tanks is common, with fresh solvent entering the tank containing most nearly exhausted material. In a typical ore-dressing operation the tanks are 53 by 20 by 5.5 m (175 by 67 by 18 ft) and extract about 8200 Mg (9000 U.S. tons) of ore on a 13-day cycle. Some tanks operate under pressure, to contain volatile solvents or increase the percolation rate. A series of pressure tanks operating with countercurrent solvent flow is called a diffusion battery. 

Batch Extractors. Coarse soHds are leached by percolation in fixed or moving-bed equipment. Both open and closed tanks (qv) having false bottoms are used, into which the soHds are dumped to a uniform depth and then treated with the solvent by percolation, immersion, or intermittent drainage methods. 

It is classification by contacting method that provides the two principal categories into which leaching equipment is divided (I) that in which the leaching is accomphshed oy percolation and (2) that in which particulate solids are dispersed into a hquid and subsequently separated from it. Each includes batch and continuous units. Materials which disintegrate during leaching are treated in equipment of the second class. 

Thiophenol was percolated through iron-free silica gel. The total iron content of the thiophenol thus obtained was about 0.5 p.p.m. Benzene (AnalaR grade) was distilled over sodium and percolated through iron-free silica gel. The total iron content of benzene thus obtained was about 0.14 p.p.m. Isooctane was redistilled and similarly treated. Curves A,A and B,B of Figure 1 were duplicate runs on two separate batches of Components prepared by this procedure. 

The Effective Medium Approximation (EMA), based in some assumptions, allows us to employ linear regressions as an approximation of the behavior of a disordered system outside the critical range. Based on EMA theory, two linear regressions have been performed as an approximation for estimating the percolation threshold as the point of intersection between both regression lines (see Figures 43 15). The values of the excipient percolation thresholds estimated for all the batches studied, based on the behavior of the kinetic parameters, ranged from 25.99 to 26.77%. 

Percolation In addition to being applied to ores and rock in place and by the simple technique of heap leaching (usually on very large scale see Wadsworth, loc. cit.) percolation is carried out in batch tanks and in continuous or dump extractors (usually on smaller scale). 

Batch extractors mix a charge of solids and solvent and then let it drain. Immersion extractors cause the solids to pass through a pool of solvent. Percolation extractors carry the solids through a vapor-light chamber where solvent rains down through the solids, dissolving out the oil, similar to the way a coffee percolator works. There are hve major types of percolation extractors basket, rotary, perforated belt, slid-ing-bed, and rectangular loop (151). 

Measurements of isotherms are commonly obtained in the laboratoiy by performing batch experiments. As has been pointed out recently by Biirgisser et al. (1993), another alternative to the classical batch experiment that allows simple and rapid measurements of an entire possibly nonlinear adsorption isotherm relies on column experiments and the use of techniques borrowed from nonlinear chromatography (Burgisser et al., 1993 Schweich et al., 1983). Experimentally, the column experiment (column is packed with the material in question) is carried out near the relevant solid/solution ratio, and the percolating solution may easily be adjusted to the composition of interest (e.g., composition of groundwater). 

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