Filtration model of high gradient magnetic filters with granular matrix

Some Aspects of Magnetic Filtration Theory for Removal of Fine Particles from Aqueous Suspensions

“…Magnetic filter performance, C, is basically expressed as follows (Sandulyak, 1988;Abbasov, 2002;Herdem et al, 1999):…”

“…One group of scientists proposes that logarithmic efficiency coefficient is not dependent on the size of captured particles, while others especially point out that this relationship is very accurate and can be expressed as j d 2 (Sandulyak, 1988). Depending on the characteristics of filtration, this relation should be j d (Watson, 1973;Gerber and Birss, 1983;Parker, 1977;Obertteuffer, 1974;Svoboda, 1987;Abbasov, 2002;Herdem et al, 1999). The relationship between j and V f is also accepted as 1/j(V f ), so that many researchers found that optimum filtration velocity of the liquid in magnetic filter is about 1000-1200 m/h, while others proved that optimum velocity is not higher than 200-300 m/h, for H , 150 kA/m, L , 1 m (Sandulyak, 1988).…”

“…Hence, higher performance is obtained at high turbulence flow regimes, which is impossible. In the literature (Sandulyak, 1988;Abbasov, 2002;Herdem et al, 1999), physical characteristics of this phenomenon have been explained by means of determining flow rate profiles of the liquid flowing in the pores of the filter. But, the particles are captured and deposited in and around the contacts of the spheres in the active regions.…”

“…The effects of liquid flow rate and size of captured particles on magnetic filter performance can be described using the following equilibrium equation for forces acting on a particle in the active regions (Abbasov, 2002;Herdem et al, 1999):…”

“…The particle-capturing mechanism in the magnetic separators was studied with two or a maximum of four filtering elements (Watson, 1973;Gerber and Birss, 1993;Luborsky and Drummond, 1975;Parker, 1977;Obertteuffer, 1974;Svoboda, 1987 Watson andWatson, 1983;Friedlaender et al, 1981;Friedlaender and Takayasu, 1982;Natenapit, 1995). However, the number of the elements used in magnetic filters is in the range of 10 3 -10 7 , and mathematical difficulties arise during the explanation of the interparticle actions under the effect of a magnetic field when classical electromagnetic theory is used (Sandulyak, 1988;Abbasov, 2002;Herdem et al, 1999). Investigations on the capturing mechanism in magnetic separators are based on the critical trajectory model (Watson, 1973;Gerber and Birss, 1993;Luborsky and Drummond, 1975;Parker, 1977;Obertteuffer, 1974;Svoboda, 1987;Watson and Watson, 1983;Friedlaender et al, 1981;Friedlaender and Takayasu, 1982;Natenapit, 1995).…”