Gravity sedimentation function

Gravity sedimentation equipment, hydrocyclones, sedimenting centrifuges or flotation cells have also been extensively used in mineral processing for separation of minerals according to density or affinity to water. In such separations, the efficiency is expressed by the Tromp curve which, similar to the grade efficiency curve, shows probability of separation as a function of material density or mineral composition. The steepness of the curve is a measure of the sharpness of the separation. 

Calculate the upper limit of particle diameter x ax as a function of particle density Pp for gravity sedimentation in the Stokes law regime. Plot the results as versus Pp over the range 0ambient conditions. Assume that the particles are spherical and that Stokes law holds for RCp < 0.3. 

Sedimentation is the partial separation or concentration of suspended solid particles from a liquid by gravity settling. This field may be divided into the functional operations of thickening and clarification. The primaiy purpose of thickening is to increase the concentration of suspended sohds in a feed stream, while that of clarification is to... 

The solubility products and reactions used here as a guideline to saturation states are given in Table VI. The results of the calculations for phosphate compounds are plotted as -log lAP (lAP is the ion activity product) as a function of depth at each station (Figs. 49 and 50). Only data from box cores collected during 1975-1976 and some selected horizons from the gravity cores are shown. Hydroxyapatite was supersaturated by a factor of lO -lO at all stations and is not plotted precipitation of this phase is known to be kinetically hindered in seawater (Martens and Harriss, 1970). Bray (1973) and Norvell (1974) inferred likely equilibrium of pore waters with whitlockite [Ca3(P04)2] in Chesapeake Bay and anoxic lake sediments, respectively. Long Island Sound pore waters also tend to have activity products close to those predicted for saturation with respect to whitlockite, although distinct undersaturation is found for most sediment intervals at NWC. 

Fig. 15. Plots of -log lAP for solid phases FeS and FeC03 as a function of depth in sediment at FOAM, NWC, and DEEP. Box cores O, summer (1975) , fall (1975) A, winter (1976). Gravity cores , FOAM , NWC DEEP.

Sedimentation analysis is commonly used and rather simple method of determining the size and size distribution function, based on the difference in particle settling rates in a gravity field. In this method a pan is placed into a homogeneously mixed disperse system, and the weight of particles, P, that accumulate on the pan, is monitored as a function of time, t (Fig. V-30). 

Transfer function depends on the hydrodynamical mode of drop motion in the settling section of the settler. In the elementary case of drop sedimentation, when drop interactions are not taken into account, the expressions for (r) are easy to obtain when the emulsion motion is perpendicular or parallel to gravity [4]. In the former case the term settler refers to a horizontal one and... 

Pearson et al. (44) compared the collision functions of various collision mechanisms, shown in Table 1. It is interesting to note that, although all the mechanisms shown are dependent on the continuous-phase properties, the droplet sizes, and the flow conditions, only sedimentation and turbulent inertia are dependent on the density difference between the dispersed and continuous phases. These two mechanisms only occur where the droplets are of different size, and their collision functions tend to zero as the droplet sizes become closer. From the collision functions of these two mechanisms it is seen that turbulent inertia will only dominate sedimentary coalescence when the characteristic acceleration is greater than that of gravity ... 

The sedimentation velocity of particles under gravity can be measured and compared with the predicted values based on no-slip and slip flow boundary conditions. The ratio of the sedimentation velocity as a function of slip length can be derived as... 

Sedimentation is a process that uses gravity as a separating force. The process that produces a solid and a liquid product also functions as a thickener. In... 

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