o- - G. Usuno… · sing of caverns be hind the shoc k wave profile. Ry the action of light...
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DISCHARGES lN \-/ATER D-r G. Usunov, nr of . S. Hi q her lnstitute of Min i.n'] a no GP olotly , So fi a 15 6 , Bu l qa ri a SUMMARY: ln case of hiqh vo lt agc electrical di sc har ges in li'lu id , th<' el Pc - trical e nergy of capacitar ba tte ry t.nrns to me c hani c al power of hioh sp eed ex p andin q di sc har qe chann e l. The energy of low temperatnre plasma is emit ed as wav es of prcssure , wh i ch at d efin it e distance f rom the wall s of the di sc har ge channel forms a sho ck wave , as well as e lectromaqn e tic and light radiation with h iq h intensity. The pa s sin g of sho ck waves from liquid nha se to s olid phase attends arising ,,f st rains, that provokes destroying of th e solid. Be sides, th e solid is under the ac tion of cavitation that. appears after clo- sin g of caverns be hind the sho ck wav e profi le. Ry the action of li ght re ac tion s tak e pla ce , simi lar to tha t, tak in q plac e by pu lsr a- di o lisis : ll20 -> n o+ 2 + e (I) ll20 e H 2 o- ( 2) H 2 o- -+ o- + 2H (3) Conditions for initiation an d speed up of oxi da tion processe s occurs. The hiqh tempe ratura of the cha nn el , as we ll as nrocesses of ioniza- tion and dissociation, takinq place init, ar e important factors too. The rate of d issolvinq is limit ed by two factors: the rat e of solid- solvent interact ion and the ra te of flusion. In cas e of e lec tric al discharge in water and naturelly un soluble mineral s , we wil Co n sid er the rat e of oxidation as rate of interaction. From the eq uation where n is the nomber of mo l es of disso lved solid q - the surface ar ea of s oli d
Transcript of o- - G. Usuno… · sing of caverns be hind the shoc k wave profile. Ry the action of light...
DISCHARGES lN \-/ATER
D-r G. Usunov, nrof . S . ~aidar - · i ~ v
Hi qher lnstitute of Min i.n'] a no GP olotly , So fi a 156 , Bu l qa ri a
SUMMARY:
ln case of hiqh vo ltagc electrical discharges in li'lu id , th<' elPc
trical e nergy of capacitar ba tte ry t.nrns to me chani cal power of hioh
speed exp andinq di scharqe channe l. The energy of low temperatnre
plasma is emite d as waves of prcssure , wh i ch at d efin ite distance
f rom the wall s of the di scharge channel forms a shoc k wave , as well
as e lectromaqne tic and light radiation with h iqh intensity.
The pa s sing of shock waves from liquid nha se to s olid phase attends
arising ,,f s t rains, that provokes destroying of the solid. Be sides,
the solid is under the a c tion of cavitation that. appears after clo
sing of caverns b e hind the shoc k wave profi le. Ry the action of
light reac tions take place , simi lar to tha t, tak inq place by pu lsra
di o lisis :
ll20 -> n o+ 2
+ e (I)
ll20 e H2o- ( 2)
H2o- -+ o- + 2H (3)
Conditions for initiation and speed up of oxi da tion processe s occurs.
The hiqh tempe ratura of the c ha nnel , as we ll as nrocesses of ioniza-
tion and dissociation, takinq place init, are important factors too.
The rate of d issolvinq is limited by two factors: the rate of solid
solvent interact ion and the r a te of flusion. In case of e lectrical
discharge in water and naturelly un soluble mineral s , we wil Conside r
the rate of oxidation as rate o f interaction. From the equation
where n is the nombe r of mo l es of disso lved solid
q - the surface area of s oli d
c1-c
2 - the change of concentration at distance 6 from the surface
follnws, that the rate of diffusion is determined by the concentratio~
gradient , the speed of particles and the area of the surface. In c a se
of electrical discharge in water conditions for maximum of all three
factors occurs. The melting of material is accompanied by intense
stiring and moving of liquid medium with high relative speed, that
takes the productions of dissolving away from the solid surface. As
to the rate of oxidation, i t is determined by the presence of oxida···
tive agents, products of decomposition of water and raise of water
temperature as result of heat transfer from the discharge channel.
EXPERIMENTAL EQUIPMENT
A hiqh voltage puls generator has been used, consisting o f hiçh
voltage rectifier, capacitors battery and ruled di s charger. The
discharge Camera was of spherical tipe with volum of 300 ml. The
discharge space is in the centre of the sphere. The suspension cir
culation has b een realized by diaphragm pump. The experiments have
been performed at conditions followed:
electrical tension between electrodes - 30 kV
discharge f requence
P'lls energy
EXPERIMENTAL DATES
- 10 Hz
- 120, 360 and 500 ~
The experiments have been per formed with samples of pure minerals,
having 100% 0-25 mm granulometry. The change of ion compos ition of
liquid is criterium of dissolving of minerals. The experimental
dates are presented in Tab1. 1, 2 and 3.
Tabl. I. Disso1ving of CuFes2
, c = 360 j
of pulses fmv] -2 +2
nomber pH Eh so Cu [mghl [mg/1]
75 6,0 - 95 65,4 25,8
150 5,5 -130 221,4 68,4
225 5 ,0 -140 397,0 125,1
375 4,4 -170 757,0 219,5 -----·
540
Tabl. 2. Dissolving of FeS 2 ,e: = 360 j
--2 Nomber of pulses pH Eh so4
[mV] fmg / 1]
75 6,5 +400 527,1
150 6,0 +346 639,6
225 5,4 +285 751,2
375 4,2 +265 922,5
Tabl. 3. Dissolving of PbS, é= 360 j
Nomber of pulses -2
pH Eh so4
---------···--- [mv] r.l!l.9i.!.L ____ . _ __ 75 6,7 -200 48,4
150 6,5 -195 63,9
225 6,1 -185 77,9
375 5,6 -160 97,9
In Tabl. 4 results of dissolving of minerals by various energies
of pulses are prese nted.
'l'abl. 4. Disso1ving of minera1s by various energies of pulses
Nomber of E: CuFes 2 Fes2
PbS pulses [ j ] ···:.-2 _ __
-2 - 2 - 2 so4 Cu so
4 so
4 fmg / 1] [mg/1] fmg/1] [mg/1]
375 120 412, 3 108,7 641,7 65,5
375 360 757, 0 219,5 992,5 97, 9
375 500 1018 ,4 315,8 121 5,4 120 , 3
Fig . l. Presents a d!, i!lqram, showing the rate of disso1ving as
function of discharge nomber.
541
527)
/ L
/ L I
/ ~c=S2
2-CuFc= S2
922 .5
75 7.0
/ 3-PbS - 3
65,1.
75 ISO 225 375 n Fig. 1. Rate of di.ssolving of minerals by enerqy of 360 j.
DISCUSSIONS
It is evident from the dates, that dissolving of minerals is of
relation with the nomber and enPrgy of pulses. The rate of CuFes2
is
the highe st one . They suppose, that recomb.ination of active radicals
take place, as well as interaction between active radicals and solid
components, chang ing this way th~ ion composition of liquid. In case
of treating pure minerals with electrical pulses, the oxidation pro
cesses runs quicly, because of active radicals-fresh solid surfaces
interaction. The runing of reactions followed is possible [11:
PbS + 6H2
o Pb(OH)2
+ -2 + lOH+ + Se (4) -+ so 4
PbS + n o+ -+ (PbS) + H2
o + H (5) 3
(PbS) + H2
o2
-+ PbSH02
+ H (6)
PbSH02
+ H02
-+ PbS03
+ H2 (7 (
The treating of CuFes2
and Fes2
has been followed by secretion
of H2S. The runing of re3ctions followed is possible:
+2 +2 -1 + -+ Cu + Fe + 2HS0
4 + 14H + 16e (8)
542
CuFeS 2 + 2Fe2
(S04
) 3
+ 602
+ 41120-> 2Cuso4 + 4Fe so4 + /, H;/' 04 (9)
CuFeS 2 + H2So4 = Cuso4
+ FeS04
+ 2H 2sf 1101
The falli.ng of pH of solutions is due to H2so4 formed. The change
of redoxpotential proofs the presence ,, f oxida tive medi um in the
Camera.
With the energy used we don't state, that this method is useful
in practice as a technology for direct leaching of mineral components
from ores. As has been shown however in our latest investigations,
as well as in [1], the redokcy processes in the pulp leads to chan
ginc; of f.i.o ·;:.at ion properties of minerais, which could be useful in
flotation. The application of electrical discharqes in water for
dissolving of gypsum and aluminium slags is well known [2] [3].
LITERATURE:
1. Ea6eHKO C.A., Kamii(KI1H H.l1., Kyre!l B.l1., J1o6aHOBa r.l1.
"VI3MeHeHI1e GJJJOTaUHOIIHOH aKTHAHO<.:TI1 CY.TJhqJI10Ht.IX MI1HepanOB
o6pa6oTaiiiii>IX 3JJCKTPI1t.JCCKI1~11i !1MnYJlhCI>I~1H paJpHJlar.m".
3neKTPOIIHaH 06pa60TKa MaTepHaJ!OA, 1973, 2.
2. raspHJJOB r.H., f'OpOACIIKO f'.l'. "Pa3PH!lHO-HMnynbCHaH
TexuonorHH o6pa6oTKH MHHepa.nbHhiX cren" KHes, HayKosa
nYMKa, 1979
3. C6opHHK "lloAoe B pa3PHllHO-HMnynbcHoi1 TexHonorHH" K11ea,
HayKosa llYMKa, 1979.
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