ON LIMITING THE VOLUME FRACTION OF PARTICLES IN THE DISPERSE SAMPLE (FOR THE TASkS ON CONTROLLING THEIR MAGNETIC PROPERTIES)

It was found that it is sufficient to have the values of magnetic susceptibility X of a disperse sample containing ferroparticles to obtain the values of magnetic susceptibility X_ч of its particles (particularly, in solving many scientific applied tasks of magnetic control and/or magnetophoresis of such particles). It is important that the values of volume fraction (concentration) γ of the ferroparticles be low (feasible), when simple dependence is acceptable for determining X_ч values: X_ч = X/γ. The question of the criterion value of γ is considered (it is still a discussion question). This value is up to γ=0.02-0.05 (this is evaluated data existing for a long time) for magnetite samples and even up to γ=0.2-0.25 (circumstantial evidence - by determining the demagnetization factor of disperse ferromagnetic samples). Direct experiments based on the ponderomotive Faraday method are realized with the use of a powder sample within the range of volume fraction γ ≤ 0.3 (for disperse phase - magnetite). The results of the experiments show that the linear part of X(γ) relation ends at γ 0.2. This is confirmed by many other consolidate data obtained by using disperse samples of magnetite (powder, colloid). However, at lower values of γ (γ ≤ 0.02-0.05) “individual” linear relation between X and γ is found as the consolidate data show. Taking into account the proportionality coefficient this relation differs from the previous relation by about 18%. This means that it is appropriate to use X values obtained at γ ≤ 0.02-0.05 for obtaining more accurate values of X_ч.

disperse phase of medium, ferroparticles, magnetite, volume fraction, criterion value, field intensity, magnetic susceptibility

1. Kawano M., Watarai H. Two-dimensional flow magnetophoresis of microparticles // Analyt. & Bioanalyt. Chem. 2012. V. 403. Is. 9. P. 2645–2653.

2. Nandy K., Chaudhuri S., Ganguly R., Puri I.K. Analytical model for the magnetophoretic capture of magnetic microspheres in microfluidic devices // J. Magn. & Magn. Mater. 2008. V. 320. P. 1398–1405.

3. Murariu V., Svoboda J. The applicability of Davis tube tests to ore separation by drum magnetic separators // Physical Separation in Science and Engineering. 2003. V. 12. № 1. P. 1–11.

4. Das S., Chakraborty S., Sushanta K. Mitra. Magnetohydrodynamics in narrow fluidic channels in presence of spatially non-uniform magnetic fields: framework for combined magnetohydrodynamic and magnetophoretic particle transport // Microfluidics and Nanofluidics. 2012. V. 13. Is. 5. P. 799–807.

5. Sandulyak A.A., Sandulyak A.V., Fethi B.M. Belgacem, Kiselev D.O. Special solutions for magnetic separation problems using force and energy conditions for ferro-particles capture // J. Magn. & Magn. Mater. 2016. V. 401. P. 902–905.

6. Sandulyak A.A., Sandulyak A.V., Ershova V.A. [et al.] Use of the magnetic test-filter for magnetic control of ferroimpurities of fuels, oils, and other liquids (phenomenological and physical models) // J. Magn. & Magn. Mater. 2017. V. 426. P. 714–720.

7. Sandulyak A.V. Magnetic filtration purification of liquids and gases. M.: Khimiya Publ., 1988. 133 p. (in Russ.)

8. Mattei J.-L., Le Floc'h M. Percolative behaviour and demagnetizing effects in disordered heterostructures // J. Magn. & Magn. Mater. 2003. V. 257. P. 335–345.

9. Baskar D., Adler S.B. High temperature Faraday balance for in situ measurement of magnetization in transition metal oxides // Rev. Sci. Instrum. 2007. V. 78. № 2. P. 023908.

10. Gopalakrishnan R., Barathan S., Govindarajan D. Magnetic susceptibility measurements on fly ash admixture cement hydrated with groundwater and seawater // Am. J. Mater. Sci. 2012. № 2 (1). P. 32–36.

11. Marcon P., Ostanina K. Overview of methods for magnetic susceptibility measurement // PIERS Proceed. Malaysia, Kuala Lumpur. 2012, March 27–30. P. 420–424.

12. Sandulyak А.А., Sandulyak A.V., Polismakova M.N., Kiselev D.O., Sandulyak D.A. An approach for choosing positioning of small volume sample at instantiation ponderomotive Faradey method in determining its magnetic susceptibility // Rossiyskiy tekhnologicheskiy zhurnal (Russian Technological Journal). 2017. V. 5. № 2. P. 57–69. (in Russ.).

13. Riminucci A., Uhlarz M., De Santis R., Herrmannsdörfer T. Analytical balance-based Faraday magnetometer // J. Appl. Physics. 2017. V. 121. 094701 (1–5).

14. Reutzel S., Herlach D.M. Measuring magnetic susceptibility of undercooled co-based alloys with a Faraday balance // Adv. Eng. Mater. 2001. V. 3. № 1-2. P. 65–67.