Mixture density, slurry

Ds = particle diameter (such that 85 percent by weight of particles are smaller than Ds = the slurry mixture density [L = hquid viscosity... 

Another term typically used to describe solid-liquid mixtures is slurry or magma density. This is usually defined in terms of the mass of solids per unit volume of solution. A 10% slurry density therefore would indicate 100 g of solids/1 of solution. Slurry density is not actually a true density but is a convenient term for indicating the amount of suspended solids in the solution. 

The mixture density of a slurry, p, in terms of the volume fraction of solids Cv is given by ... 

Although density is essentially a static property, absolute (or dynamic) viscosity is a dynamic property and tends to reduce in magnitude as the shear rate in a pipeline increases. Thus, engineers have had to define different forms of viscosity over the years, everything from dynamic viscosity, to kinematic viscosity, to effective pipeline viscosity. The effective pipeline viscosity will be discussed in detail in Chapters 3, 4, and 5. In this chapter, the reader is introduced to basic concepts of the mixture of slurry in a stationary state. This is effectively what the pump, or a mixer, might see at the start-up of a plant. As is often the case, when the driver cannot deliver enough torque to overcome the absolute (or dynamic) viscosity, the operator is forced to dilute the slurry mixture. 

The general manufacturing scheme for phosphate salts is shown in Figure 11. Condensed phosphates are prepared from the appropriate orthophosphate or mixture of orthophosphates, so the preparation of orthophosphates must be considered first for the manufacture of any phosphate salt. Phosphoric acid is neutralized to form a solution or slurry with a carefully adjusted acid/base ratio according to the desired orthophosphate product. The orthophosphate may be recovered either by crystallization from solution, or the entire solution or slurry may be evaporated to dryness. The dewatering (qv) method is determined by the solubihty properties of the product and by its desired physical properties such as crystal size and shape, bulk density, and surface area. Acid orthophosphate salts may be converted to condensed phosphates by thermal dehydration (calcination). 

If a waste is a mixture of water and organic liquid, you must report it as wastewater unless the organic content exceeds 50 percent. Slurries and sludges containing water must be reported as solid waste if they contain appreciable amounts of dissolved solids, or solids that may settle, such that the viscosity or density of the waste is considerably different from that of process wastewater. 

Specific weight is one of the most important properties of a cement slurry. The specific weight of a certain dry cement regulates the minimum or maximum amount of water allowed to be added. The minimum amount of water, from the aspect of density, is greater than the stoichiometric quantity necessary for proper setting. If more than the maximum amount of water is used, pockets of free water will be formed in the set cement column. Typical amounts of water range from 38% to 46% by weight in the final mixture. 

If the machine is separating a solid-liquid mixture, the mean density of the slurry in the bowl should be used in equation 13.131. 

In order to develop a continuous flux maintenance procedure, the present study examined the transmembrane flux values from the cross-flow filtration module with a filtration media area of 0.0198 m2 (0.213 ft2), a slurry density of approximately 0.69 g/cm3 at 200°C, 17 kg of simulated FT wax with a catalyst loading of 0.26 wt%, and a TMP between 0.68 and 1.72 bar (10-25 psig). The filtration process was run in a recycle mode, whereas clean permeate was added back to the slurry mixture, thus allowing the catalyst concentration to remain approximately constant over the course of the run (given minor adjustments for about 5 ml permeate and slurry samples collected throughout the test). 

In a hydraulic jig, a mixture of two solids is separated into its components by subjecting an aqueous slurry of the material to a pulsating motion, and allowing the particles to settle for a series of short time intervals such that their terminal falling velocities are not attained. Materials of densities 1800 and 2500 kg/m3 whose particle size ranges from 0.3 mm to 3 mm diameter are to be separated. It may be assumed that the particles are approximately spherical and that Stokes Law is applicable. Calculate approximately the maximum time interval for which the particles may be allowed to settle so that no particle of the less dense material falls a greater distance than any particle of the denser material. The viscosity of water is 1 mN s/m2. 

Detonation in Slurry Explosives. Cook, in his book, pp 316-21, described under the heading "Water-Compatible Explosives properties of slurry explosives developed by M.A. Cook.St H.E. Farnam. These expls were intended for use in large diameter underwater blasting at Iron Ore Company of Canada s Knob Lake operation. The success of these expls brought out the importance of pressure and density on the products of detonation. Table 12.21 of Cook s book gave computed properties of three dry versus water soaked slurry mixtures at AN/TNT ratios of zero, 1.0 8c 3.25. It was of interest to note that the computed (dry basis) available energy A of the TNT in slurry with 27% water was 17% greater... 

In short process lines slurries are readily handled by centrifugal pumps with large clearances. When there is a distribution of sizes, the fine particles effectively form a homogeneous mixture of high density in which the settling velocities of larger particles are less than in clear liquid. Turbulence in the line also helps to keep particles in suspension. It is essential, however, to avoid dead spaces in which solids could accumulate and also to make provisions for periodic cleaning of the line. A coal-oil slurry used as fuel and add waste neutralization with lime slurry are two examples of process applications. 

---