Cake volume

Diatomaceous Silica Filter aids of diatomaceous silica have a dry bulk density of 128 to 320 kg/m (8 to 20 Ib/fU), contain paiiicies mostly smaller than 50 [Lm, and produce a cake with porosity in the range of 0.9 (volume of voids/total filter-cake volume). The high porosity (compared with a porosity of 0.38 for randomly packed uniform spheres and 0.2 to 0.3 for a typical filter cake) is indicative of its filter-aid ability Different methods of processing the crude diatomite result in a series of filter aids having a wide range of permeability. 

Cake Dryness In dewatering, usually the cake needs to be as diy as possible. Cake diyness is commonly measured by the solids fraction by weight W or by volume ,. The moisture content is measured by the complement of W or ,. The volume fraction of the pores and void in the wet cake is measured by the cake porosity (= 1 — ,) whereas the volume fraction of the liquid in the pores of the cake is measured by the saturation S. For welf-defined solids in the cake with sohd density (bone diy) p, and hquid density Pl, and given that the cake volume... 

Defining the ratio of cake volume to filtrate volume as x , then the cake volume is x V, The cake volume also may be expressed by the product h,A, where h,. is the cake height in m. Hence,... 

This expression can be represented graphically in dimensionless form to simplify its use. It is generally expressed as the so-called filtration number , defined as follows E, = /iR, / 2APT3 jr x . The filtration number, E, is dimensionless and varies from zero at Rf = 0 to a large value when there is an increase in the viscosity of the sludge and Rf or a decrease in pressure drop, auxiliary time, specific cake resistance and the ratio of cake volume to filtrate volume. It may be assumed in practice that F(, = 0 to 10. If washing and drying times are constant and independent of filtration time, they may be added directly to the auxiliary time. In... 

We denote the ratio of cake volume to filtrate volume as Xq. Hence, the cake volume is XoV. An alternative expression for the cake volume is hcA where he is tire cake height in meters. Consequently ... 

Nutsche filters are well suited for handling flammable, toxic, corrosive and odor-noxious materials since they are autoclaved and designed for use in hazardous and ex-proof environments when extremely safe operation is required. They are available in almost any size with the larger machines for a slurry filling batch of 25 m and a cake volume of 10 m Such filters have a filtration area of 15 m and are suitable for fast filtering slurries that produce readily 0.5 m thick cakes. The basic configuration is shown in Figure 11. 

Specific cake volume. Where v = volume of particulate cake deposited when unit volume of clear filtrate is collected. 

Flaxseed powder and oat bran were utilized as a fat replacer in cake without any detrimental effects (Lee et al., 2004b). Flaxseed significantly decreased viscosity at 20% however, an increase in cake volume was observed, potentially due to the high lipid content which served as a shortening in the presence of nonstarch polysaccharides. However, more data are required to explain the observed phenomenon. Flaxseed powder addition significantly (p < 0.05) darkened crumb color and increased yellowness values. Results indicated that flaxseed was an acceptable additive when used with Nutrim oat bran. 

Shortening Composition Specific Cake Volume Experimental/ControIxlOO (%)... 

Reduction of Salt Cake Volume. Hanford salt cake contains at most only a few milligrams of long-lived (ti/2 > 25y) radionuclides per metric ton. Any decision to remove the salt cake from the present tanks, immobilize it, and store it elsewhere either onsite or offsite provides strong incentive to concentrate the radionuclides and thereby reduce significantly the volume of inert material which must be immobilized and/or stored. 

Removal of Sodium. Workers at the Battelle Pacific Northwest Laboratories (PNL) have recently published (21) results of a literature search and preliminary experiments performed to determine the feasibility of reducing salt cake volumes by the removal of sodium and purifying the sodium as metal for reuse or, at least, restricted storage. Methods considered by these scientists for removal of sodium from water solutions of salt cake included ... 

Figure 5. Conceptual salt cake volume reduction scheme...

Wash volume is 1—2 cake volumes, applied in one or two portions. 

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