HUNG~ JOURNAL 
OF lNDUSTRIAL CHEMISTRY 

VESZPREM 
Vol. 29. pp. 11 - 15 (2001) 

MODIFIED SCALE CRYSTALLIZATION AND DISPERSION STABILITY IN 
MAGNETIC WATER TREATMENT 

L. C. LIPUS, J. KROPE, L. GARBAI1 

(Faculty of Chemistry and Chemical Technology, University of Maribor, Smetanova 17, 2000 Maribor, SLOVENIA 
1Mechanical Engineering Faculty, Tebnical Univesity of Budapest, Mtiegyetem rkp. 9, Budapest H-1521 HUNGARY) 

Received: November 30, 2000 

The effects of magnetic water treatment (MWT) devices are discussed with the emphasis on modified dispersion stability 
and modified CaC03 crystallization. MWT mechanism, most probably consisting of several interacting effects, is 
strongly dependent on water composition, solid phase presence and working conditions. 

Keywords: water treatment, magnetic hydrodynamics, water dispersion systems 

Introduction 

MWT is an alternative method of water conditioning for 
scale control. It has also become important for 
amelioration in other industrial dispersion areas. MWT 
equipment has had practical application for over half a 
century. 

Working experience has shown it to be a cheap and 
non - polluting application for hard scale prevention, 
and the improvement of dispersion separation [ 1-4]. 

Several empiricaUy - based designs of MWT 
devices have been produced. However, their 
mechanism, how a magnetic field precisely acts in a 
treated water system, still remains uncertain. A precise 
theoretical understanding is crucial when designing 
reliably efficient equipment for specific technological 
systems because of the delicate dependency on water 
composition and operational conditions. 

Certain theoretical conclusions have been reached 
from widespread laboratory research. These state that 
the process of modified scale crystallization and 
dispersion destabilization most probably consists of 
three parallel interacting steps: 

- magnetically modified hydration of ions and solid I 
solution interfaces, 

~ Lorentz force effect on water dispersion systems and 
- concentration effects in working channels of MWT 

devices. 
These three hypotheses are being developed. Firstly, 
there is a theoretical possibility of magnetic resonance 
of two neighbouring protons in hydration net during 
magnetic treatment, which could cause spin transition 

from a ground state (anti- parallel orientation of spins) 
into an agitated state (parallel orientation). This would 
indirectly lead to weakening of the hydrogen bond [5}. 

Secondly, during the use of the dynamic MWT type, 
the Lorentz force, FL (Eq.l), occurs on ions in the 
solution causing them to shift towards the surfaces of 
the dispersed particles (Eq.2). Therefore, the stability of 
water dispersion could be affected [6J. 

where parameters are: 

B =magnetic field density, 
e = electric charge, 

eo= electron charge= l,6·IO·l9As, 
r1 = ion radius, 

{1} 

(2) 

v = flow velocity of dispersion through the 
channel of MWT device, 

Ax; = Lorentz shift of ion, 
z1 = ion valence, 
11 = water viscosity, 
z = retention time of dispersion in channel of 

MWTdevice. 

The B'tV product is known as the technical module 
and is an important criterion for the practical efficiency 
of MWT devices. 

Thirdly, concentration effects partially explain the 
aggregation of fine, already destabilized, particles into 



12 

X 

- 0 /' 
/ 

I • 
I 0 
\ X 

Fig.l Scheme of electric layer and adherent electrical potential 

bigger ones. whilst modified crystallization and 
destabilization of dispersed scale forming components 
are better explained by the first two hypotheses. 

Which mechanism prevails, depends on water 
composition and treatment conditions. The MWT 
mechanism's action on dispersed particles will be 
discussed here. 

Possible explanations for magnetic destabilization of 
water dispersions 

It is well known that dispersed particles are essentially 
electrically charged on their surfaces even at very low 
solution concentration of electrolytes due to both the 
dissociation of the solid surface in contact with water 
molecules, and the selective adsorption of electrolytes 
from bulk solution. The ions which are adsorbed on 
Stllid surfaces are named co -ions. In the surrounding 
water layer, so called counter~ions are concentrated for 
the neutralization of the charged solid surface. The 
double electrical layer theory (Voyutski (1), 1979; 
Hunter {8), 1996) describes the concentration 
distribution of counter - ions and adherent electrical 
porendals, as is shown in Fig. 1. 

The neutralization layer consists of two layers: the 
Stern layer - the first. thin and condensed layer due to 
the strong electrostatic and adsorption a~ttactions of 
counter - ions to sotid surface. and of the Gouv -
Chapman layer - the second. '1.\ider and scanered l~yer 
due to l\Uker electrostatic aruactions and the thermal 
motion of the ions. The distribution of counter - ions in 
the Slern layer is quantitatively siml!ar to Langmuir 
adsorption (represented by equation (4). whilst the 
disttibution in the Oouy - Chapman layer is determined 

by the Boltzmann equation (5). The electrical potential 
as a function of distance to solid surface (equation (6) is 
derived from the Poisson equation (8) together with 
equation (5). Parameters in these equations are defined 
in the nomenclature. . 

(3) 

c"" +exp((8± ±ZF<p8 )/ RT) 
(4) 

c+ = c"" exp(± ZF<p I RT) (5) 

tanh(ZF<p) = tanb(ZF(/Js )exp(-K(x-8)) (6) 
4RT 4RT . 

?~ 2 
2F- "-'Z; ci= 

K = 11---'~---
RTc 

(7) 

Characteristic parameters of dispersion stability are 
<p0 - electrical potential on the Stem border and K -
Debye - Ruckel parameter. Namely, in most stable 
dispersions, the failure of particle collisions due to 
electrostatic repulsion in an overlapped electric layer, is 
responsible for very slow coagulation. The more 
condensed and thinner the layer is, the more particles 
are neutralized and able to aggregate. The electrical 
potential of the Stem layer - <p0 depends on its 
composition, which is specific for each solution I 
dispersion system. A determination of the precise (/1 0 -

value is difficult. Usually, the empirical parameter t;-
electrokinetical potential of slipping plane, is taken as 
an approximation for <p0 .. 

The possible mechanism for magnetic 
destabilization could be predicted by measuring 
electrical conductivity, pH and C- potential. Theoretical 
possibilities are schematically shown in Fig. 2. 
Alternatively, the abundant precipitation of aragonite 
could be explained by Lorentz ion shifts, which have an 
influence on the value of ko and on the concentration of 
crystal - forming ions at the growing surface. Surfaces 
of CaC03 particles in natural waters, which are 

commonly neutral or slightly acid, are charged 

positively. therefore, ca.2+ ions could be considered as 
co - ions. Table l shows that shifts of ca2+ are by a 
factor of 3.8 longer than the HC03-, which drastically 

~ten the relativ~ concentrations of crystal - forming 
mns on the groWing surface and accelerates the caco3 
growth according to Eq. (9). 



Table I Lorentz ion shifts and relaxation times at Bv ;: 0,2 
Vim and -r = 0, I s for some ions at room temperature 

I Na+ Mg2+ Ca2+ HC03 sol 
r;(I0-10m) 0.95 0.65 0.99 1.85 2.3 

Z; +1 +2 +2 -1 -2 
L1x;(nm) 1.8 5.3 3.4 0.9 1.5 

Threshold inhibitors (i.e.Mg2+, Fe2+, zn2+) of the 

calcite growth have smaller radii than ca2+. Their 
incorporation into active calcite sites and their more 

intensive hydration than ca2+- ions retards the calcite 
growth and gives priority to the aragonite growth. This 
is more favourable from the viewpoint of hard scale 
prevention due to its lower adhesivety. Table 1 shows 

that shifts of Mg2+ are by a factor of 1.5 longer than 

that of ca2+. This leads to a concentration rise of Mg2+ 
- ions on the growing surface, lowers the value of ko in 
Eq.(9) for calcite and gives priority to the aragonite 
formation. 

Conclusion 

The key to MWT effectiveness in hard scale prevention 
is the forming of modified large crystals, which in 
supersaturation conditions serve as a basis for scale 
precipitation in a suspended form. 

The MWT mechanism could be considered as 
complex, strongly linked with the presence of solid 
surfaces and consisting of several phenomena. 

The modified hydration could essentially affect 
water dispersions and solutions even under static 
magnetic treatment. However, the most successful 
MWT devices are of the dynamic type (with the flowing 
of supplied water through static or pulsated magnetic 
fields) where the Lorentz effect on solid surfaces could 
become more noticeable and prevail under the effects of 
hydration. 

SYMBOLS 

Magnetic field density, V stm2 
i - counter - ion concentration in bulk 

solution, moifm3 
Electrical charge, As 
Electron charge= 1,6·10-19 As 

Activation energy for dehydration of crystal 

-forming ions, J/mol 
Factor of ionic strength - I, dimensionless 

Faraday constant= 9,6·lo4Aslmol 
Lorentz force, N 
Empiric parameter of water impurities, 

m/smol 
Solubility product of CaC03, mot2/m6 

r; 

R 

s 
t 
T 

Z; 

Ion radius , m 
general gas constant= 8,3J/molK 
Crystal surface, m2 
Time, s 
absolute temperature, K 
radial coordinate, m 
Lorentz shift of ion, m 
i - ion valence, dimensionless 

Greek Symbols 

t: dielectric constant of fluid, As/Vm 
1] water viscosity, Nstm2 
(jJ electrical potential, V 
qJ

0 
(jJ on solid surface (x = 0), V 

(jJ 
8 

(jJ on Stern border (x :::: 8), V 

13 

K Debye- Hiickel parameter, defined by (6), 
lim 

e adsorption energy, J/mol 
CJ' surface electric charge density, As/m2 
-r retention time of dispersion in channel of 

MWT device, s 
!; electrokinetical potential at slipping plane {;v; 

=A), V 

REFERENCE 

1. DONALDSON J.D.: "Magnetic Treatment of Fluids-
Preventing Scale"; HDL Symposia at the 
Universities of York and Aston, January 1988, New 
Scientist, p. 117, (1988). 

2. KLASSEN V.I.: "Magnetic Treatment of Water in 
Mineral Processing"; Developments in Mineral 
Processing Part B, Mineral Processing, pp. 1077~ 
1097, (1981). 

3. HIBBEN S.G.:"Magnetic Treatment of Water"; 
National Technical Information Service, No. 1622-
4, (1973). 

4. GRUTSCH J. F.: USA/USSR Symposium on 
Physical~Mechanical Treatment of Wastewaters p. 
44, EPA~ Cincinati, (1977}. 

Alternatively, the abundant precipitation of aragonite 
could be explained by Lorentz ion shifts, which have an 
influence on the value of ko and on the concentration of 
crystal - forming ions at the growing surface. Surfaces 
of CaC03 particles in natural waters, which are 

commonly neutral or slightly acid, are charged 

positively, therefore, ca2+ ions could be considered as 

co - ions. Table 1 shows that shi'fts of ca2+ are by a 

factor of 3.8 longer than the HCO:[. which drastically 
alters the relative concentrations of crystal - forming 
ions on the growing surface and accelerates the CaC03 

growth according to Eq. (9). 



14 

Table 1 Lorentz ion shifts and relaxation times at Bv == 0,2 
Vim and -r = 0,1 s for some ions at room temperature 

1 Na+ Mg2+ Ca2+ HC03 sol 
r; (10-10m) 0.95 0.65 0.99 1.85 2.3 

Z; +1 +2 +2 -1 -2 
Ax;(nm) · 1.8 5.3 3.4 0.9 1.5 

Threshold inhibitors (i.e.Mg2+, Fe2+, zn2+) of the 

calcite growth have smaller radii than ca2+. Their 
incorporation into active calcite sites and their more 

intensive hydration than ca2+- ions retards the calcite 
growth and gives priority to the aragonite growth. This 
is more favourable from the viewpoint of hard scale 
prevention due to its lower adhesivety. Table 1 shows 

that shifts of Mg2+ are by a factor of 1.5 longer than 

that of Ca2+. This leads to a concentration rise of Mg2+ 
- ions on the growing surface, lowers the value of ko in 

Eq.(9) for calcite and gives priority to the aragonite 
formation. 

Conclusion 

The key to MWT effectiveness in hard scale prevention 
is the forming of modified large crystals, which in 
supersaturation conditions serve as a basis for scale 
precipitation in a suspended form. 

The MWT mechanism could be considered as 
complex, strongly linked with the presence of solid 
surfaces and consisting of several phenomena. 

The modified hydration could essentially affect 
water dispersions and solutions even under static 
magnetic treatment. However, the most successful 
MWT devices are of the dynamic type (with the flowing 
of supplied water through static or pulsated magnetic 
fields) where the Lorentz effect on solid surfaces could 
become more noticeable and prevail under the effects of 
hydration. 

B 

SYMBOLS 

Magnetic field density, Vsfm2 
i - counter - ion concentration in bulk 

solution, mo1Jm3 
Electrical charge, As 
Electron charge = 1 ,6·1 o-19 As 
Activation energy for dehydration of crystal 

-forming ions, J/mol 
Factor of ionic strength -1, dimensionless 

Faraday constant= 9,6·1o4 As/mol 
Lorentz force, N 
Empiric parameter of water impurities, 

rnlsmol 

Ks Solubility product of CaC03, mol2Jm6 

r; 

R 
s 
t 
T 

Z; 

Ion radius , m 
general gas constant== 8,31/molK 
Crystal surface, m2 
Time, s 
absolute temperature, K 
radial coordinate, m 
Lorentz shift of ion, m 
i - ion valence, dimensionless 

Greek Symbols 

s dielectric constant of fluid, AsNm 
1] water viscosity, Nsfm2 
qJ electrical potential, V 
({J

0 
qJ on solid surface (x == 0), V 

(/J 
0 

(/Jon Stern border (x = 8), V 
K Debye -Ruckel parameter, defined by (6), 

lim 
e adsorption energy, J/mol 
a surface electric charge density, Asfm2 
-r retention time of dispersion in channel of 

MWT device, s 
s electrokinetical potential at slipping plane (x 

= Ll), v 

REFERENCE 

5. DONALDSON J.D.: "Magnetic Treatment of Fluids-
Preventing Scale"; HDL Symposia at the 
Universities of York and Aston, January 1988, New 
Scientist, p. 117, (1988). 

6. KLASSENV. I.: "Magnetic Treatment of Water in 
Mineral Processing"; Developments in Mineral 
Processing :Part B, Mineral Processing, pp. 1077-
1097, (1981). 

7. HmBEN S.G.:"Magnetic Treatment of Water"; 
National Technical Information Service, No. 1622-
4, (1973). 

8. GRUTSCH J. F.: USA/USSR Symposium on 
Physical-Mechanical Treatment of Wastewaters p. 
44, EPA- Cincinati, (1977). 

9. LlPUS L. and KROPE J.: ''Modified scale 
crystallization in mag~etic water treatment"; The 
International Congress of SITHOK, Maribor, No.4, 
PP- 40-41, (2000). 

10. LlPUS L., KROPE J. and GARBAI L.: " Magnetic 
Water Treatment for Scale Prevention"; Hung. J. 
Ind. Chern. 1998, 26, 109 

11. VOYDTSKI S.: "Colloid Chemistry"; MIR publisher 
Moscow, (1978). 



12. HUNTER R. J.: "Introduction to Modern Colloid 
Science"; Oxford Science Publications, New York, 
(1996). 

13. TOMBACZ E., MA C., BUSCH K.W. and BUSCH 
M.A.:Coll. Poly. Sci. 1971, 269,278 

14. HIGASHITANI K., OKUHARA K. and HATADE S.: J. 
Coll. Interface Sci. 1992, 1, 152 

15. HIGASHITANIK. and OSHITANIJ.: Trans I. Chern. E, 
1997, 75, 115 

16. GRIMES S.M.: "Magnetic Field Effect on Crystals"; 
Tube International, March (1988). 

17. 

18. 

19. 
20. 

15 

HIGASHITANI K., KAGE A., KATAMURA S., lMAIK. 
andHATADES.: J. Coll. Interface Sci.1993, 156, 
90 
NANCOLLAS G. H. and REDDY M. M.: "Crystal 
Growth Kinetics of Minerals Encountered in Water 
Treatment Processes"; -Environmental Chemistry 
of Metals, New York, (1974). 
NIELSEN A. E.: PureAppl. Chem.1981, 53,2025 
KLASSEN V.I.: "Magnetization of water systems"; 
Himija, Moscow, (1982). 


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