Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~3C~Z58
,; . ~
The inve~tion relates to a me*hod a~d an apparatus
for activating comminution of minerals, ores and ~otation
concentrates tllat can undergo ~lotation or are enriched
by ~lotation~ hearth washing, tub washing, neavy fluid
separation, magnetic separation, electrostatic separation
and the like, which have undergono preliminary comminution
to a suitable grain size, preferabl~ smaller ~h~ 7 - iO mmy
and if necessary, have been dried to give a residual moisture
content o~ less than 8 - 10 %.
Numerous mineral raw materials re~uire e~ective enrichment
1~ the oourse o~ their ~repar~-tion to malce tlleir subse~uent
prooessin~ economical. One method o~ e~rloh~e~t i~ ~lot~tion
in whioh the ~ar~ing hydrophobio or hydrophilio nature~ o~ the
granule surfaces are e~ploited in order to bind mineral particles
to rising ~ir bubbles ~nd have them conveyed by the latter into
a ~loating foam bed, or to leave them in a soaked submerged
~tate and finally extract them as hea~y medium. Ei~eotive
~lotation presupposes above all else, in addition to suitable
preparation o~ the granule surfaoes with chemical additives,
that the mineral components, ore and dross ha~e been separatad
~rom one another by sufficient comminu-tion.
Accordingly the co~minu-tion must go beyond -the size o~ the
mineral components oontained in the raw ore or untreated rockp
i.e. match the level oi i~tercrescence.
The oomminution method~ normally used merely reduced
granule size and the e~ergy in~u~ed i~to t~e material in the
- ~ 2 -
.
.,
~
:~13~
process is li~ited to tha~ Or the sur~ace additionally created9
and thus to increased adsorption capacity. Eowev0r co~minution
processes have also become k~o~n which apart from reducing
granule size also bring about a so-called mecha~o-chemioal
activation of the co~minut0d substance ~nd there~ore impart
more tha~ pure surface energy. The use o~ such processes in
conjunction with the enriohment of ores a~d minerals by
flotation has not become known however, and it was never to be
anticipated - also because the theoretical basis ~or the
phenomena observed still has not been ¢lari~ied - that special
adva~ta~es would be obtainable ln connection with the very
pecullar requirements o$ these preparatory processes. But it
has been found - and this is the basis for the present
invention - that "activatin~" comminution o~ the kind
indicated can result in the mineral components acquiring other
additional properties to those obtained after conventional
comminution, properties which can have an influence on sub-
sequent processing operations, at least in regard to yield.
Thus we haYe been able to demonstrate that copper ores
comminuted in this way firstly gave a higher yield per process
stage during flotation and secondly duri~g the subsequent
metallurgical process far less copper passed into the slag
than wa6 the case with conve~tionally comminuted ore or
oonee~trateO ~hus two advantages were obtained in that both
the ilotation process and the smelting process were more
efficient and thus additional process stages could be eliminated.
,
- 3 -
.
;,
The sa~e results, although with differenoes in yiel~ ~rom
ore to orc or mineral to mineral~ can also be obtained with
other ores or minerals. In all after mechano-chemically
activa-ting co~minution a~ improvemen-t in ~l~tation in the ~orm
o~ increase~ selectivity or increased yield gr both to~ether
with an improvement i~ the smelting properties or chemical
decomposition characteristics can be expected. In additiong
there was one ~urther phe-nomenon that is particularly valuable
with re~ard to the preparation o~ comple~ ores: Mechano-
chemically activatlng comminution results in the dissolutîon
of the grain structure, partioularly at the grain boundaries,
being bro~en up -to an appreciabl~ great0r d~r~e th~n with
other oon~inution method~; which has a ~urther re~ult in that
it malces more oomplete separation o~ the individual ore
components possible. Naturally cases can also arise ~Yhere
mechano chemioal activation does not appear possible be~ore the
~lotation9 e.g. when ~lotation or another sor~ o~ enrichment
process ~such as ~or e~ample hearth-waslling, heav~-~luid~
magnetio or electrostatio separation has already been carried
out and t~e ~i~al concentrate arrives ~or smelting or
decomposi-tion, and also when some preliminary clea~ing may be
necessary durin~ which the water in the pre-washed raw mineral
would h~Ye to be remo~ed ~or mechano-chemical activation bu~
has to be omitted ~or reasons of space or cost~ I~ suoh
cases one will have to manage without the advantage o~ mechano-
chemical acti~ation for the ~lotatio~ process a~d will only
1~3~ZS1 3
be able to utilise the advantage for the smelting or decomposition.
According to an aspect of the invention there is
provided a method of comminuting and activating mineral components
selected from the group consisting of minerals and ores to
improve the separation of the mineral components during flotation
comprising comminuting the mineral components to reduce the
grain size and activating the comminuted mineral components by
subjecting the comminuted mineral components to mechanical
shocks or shock impulses, the activation resul~ing from the
mechanical shocks or shock impulses comprising a mechano-chemical
activation.
In the following the device for implementing the
method in accordance with the invention is explained with
reference to the drawings. In these fiyures 1 to ~ show various
types of embodiment of the device in highly simplified
illustrations, figures 5 and 6 show a special kind of mixing
device in section and in a side view respectively.
Suitable devices for implementing the activating
comminution method in accordance with the invention are made '
from components known per se and basically contain no new
elements both as regards these components or their arrangement.
Figures 1 - 4 give examples of such arrangements even if they
do not constitute the only possibilities for these.
Figure 1 shows the example of preliminary crushing in
a rod mill 1 from which the crushed material is discharged
directly to a device 10 with the ability to carry out the
mechano-chemical activation. From this device the ma-terial,
comminuted further to the desired final degree of fineness,
passes directly into a conditioning unit 11 whence it is fed
to a flotation unit.
Figure 2 gives the example of two-stage comminutlon,
the second offering the mechano-chemical activation, with
pc/ ,~
~` ~13~'25~3
washing in between to remove clay-like material for example.
Once again a rod mill 1 is provided which hardly leaves any .
oversi~e lumps in the crushed material and therefore it is not
- 5a -
pc/,~
. ,~ ., j,
~13~$~
absolu-tely essential I'or it to be ~un in closed circuit with
a screening device. The crushed mater:ial ~rom rod mill 1
passes into a rake classifier or a bowl classi~ier 2 with a
grid outlet uni-t in which clay~ e e:Lements are washed out.
The sandy ~ischarge from this washing unit 2 is largely
drained o~ water on a horizontal filter 8 before the pre~
crushed and washed mineral is comminu-ted to the desired final
degree o~ fineness in device 10, being mechano-chemically
activated in the process. Again a conditioning tan~ 11 is
provided before a :~lotation ~nit ~or tho completely
co~minuted mnterial.
Fi.gure 3 concerns the treatment o~ ~linorals with basically
stubbornly adheri~g impuritios like clay. Comminution is
carried out ~irst9 with or without circuit grading, in a
ball mill 3. The material co~ uted there is i~te~sively
~ashed in a battery of a-ttrition cells 1~, then collected in a
sump 5, mo~ed to an armoured dewatering hydrocyclone 7 by
means o~ an armoured rotary pump 6 and separated ~rom minute
abraded par-ticles. In the attrition cells the particles of the
material bei~g treated are rubbed against each other so that
layers of clay and other undesired parts which sit on the
sur~ace o~ larger grains are rubbed o~f and w~hed away. ~le
pump sump 5 is a compensating vessel from which t~le pump is
taking in and in ~hich, corresponding to the changing ~eedin~7
the mass rises with increased feeding but drops with decreased
~eeding. Additionally a ~loat swi-tch may be providea so that
the pump cuts of~ with a low le~el. As the washed underflow
~3~,~58
emerging from the hydrocyclone still e~hibits a moisture
content oI abou-t 25 - 30 ~, i-t is drained o~ water in a
pusher centri~uge 9 and the drained ~ashed material is
~inally comminuted to the ~inal degree of fineness and
simultc~neously mechano-chemically ac-tivated in the device 10.
The material so treated passes via the conditioning tan~ 11
to the flotation unit.
Las-tly ~igure 4 shows the treat~ent of a concentra~
intermediate product that has undergone ~lota~ioll. T}-le prc,.~uct 9
still T~et, is drained o~ water on a ~lat ~il-t~:r & an~
~ollowing pusher contxi~u~e 9 and is then mechano-che~ic~
aotivatcd in the dovico 10 l~ith sim-ultaneous ~urthcr
comminution. The activated product is stored in a silo
before it is used further~ ~or example carried off, smel~e~
decomposed or given ~urther ~lotation treatment~
The most essential feature of this device is the
provision o~ a special kind o~ mixer 10. This special r~i~er
stands out above all as mal~ing it nossible to impart a
co~paratively large amount o~ ener~y ~lechanically to t~le
material supplied9 resulting on the one hand in the initiation
and completion of a comminution process ~nOT~ per se and o~ t.le
o-ther hand in mechanical infusion o~ energy such that through
the coinciclence of suitable resonance-like phenomena changes
that are stable o~er ~ period o~ time occur in the sub-
microscopic structure o~ the substance so treated~ produ~ g
modi~ied behaviour o~ this ~ery substance in subsequent
~3~
reactions. Such proc~sses an~ phenomena have already been
widely clefined and.inves-ti~atecl ancl have passed into
specialist literature wlder the terms ~mechano-chemical
activation", t'energy infusion" etc.
Plodi~ied pin~ed dis~ mills, preferably with ro-tors
driven in contra-rota-tion9 have prov~d to he suitable devices
for such mechano-chemical activation~ The last-~amed devices,
known as ~disintegrators", have tll~ aavantage of variable
rotational speed and thus impact speed co~pared with the
ball mills so that adaptation o~ tlle impact energy levels and
impact times to the speciiio charaoteristics o~ the material
bein~ treated is made ~ossible. ~all mills, even with low
hourly outpu~, remain i~ contrast less ~le~iblo ~n ~he ~ace
of changing raw m~terial requirements because of the narrowness
e~ e ry e~', c'~/J~
of the ~æg~$~e~}}y highly effective resonance b~nd ancl
consequently have a narrower range of application to sneci~ic
materials, although hehaviour is more ~a~oura~le as regarcls
wear in the case where the material ~ed in is inherently very
hard and therefore hi~hly a~rasive. S-~nce, as mentiollecl
previously, ball mills clo not nermit ally grindirlg operation
de~ined in terms of numher~ timing ~ld intensity o~ the
strokes o~ the grinding elements acting on the individua~
particles of the ~aterial being ground (~hich is the case ~ith
disi~tegrators ~Yith closely defincd process para~eters such as
nu~ber of beater rings~ dis-t~nce between the ri~gs and between
the bea~ers ~i-thin each ring, ~orm ~nd align~lent of the
- 8 -
~3(~
beaters, speed ol' rotatio~ of the grinding disks)~ these are
more sui-table, as indicatcd at the start 9 ~or use in processes
~here the instantaneous chance activation of individual
particles or spatially li~ited ~ones o~ SUCil7 due to the
presence o~ thc necessary reagents7 e~g, chemicals having
a dissolving action in -the case o~ leac11ing processes, per-
mits temporally and spatially i~edia-te use o~ the activation
pheno~ena occurring but not necessarily stable over a period
of ti~e cluring the grincling operation. It is possible at any
rate to add certain chemicals, even in disintegrators~ during
the oomminution stago ~or the purpose of obtaining as homogenous
and ~inoly disL~crse~ a~lixture as possiblo, ~hich would ~e so
~uch harder to achie~e in a conventional mi~cr. ~pparently
similar proceclures have been sugges-ted in -the pas-t~ e. g. in
US PS 4 014 ~74, but for the di~ere~t purpose o~ libe~
~anci making available new sur~aces ~y crushing ~urther in ball
mills ~or instance be-tlreen two s-tages of multi-stage flotation
processes with stage-by-stage separation o~ di~ferent ores
a~ter chemical neu~tralisation o~ chemicals -that ha~e been used
as collectors in the prececling stage, such that the ~lo-tation
characteristics o~ these nel~ sur~aces can only ta~e ef~ect in
the next stage. Figures 5 ancl 6 show the fundamental
structure o~ a disintegrator.
In the case o~ tAis activating device~ ~illing disks 29 and
30 are ~ixed to the end of two ~loating shafts ~7 and 28, which
are provided on the sur~aces ~acaci to another ~ith concentric
_ 9 _
~L~3~
rows o~ milling and stril~ing tools, as ~or ins-tance s-ticlss,
plugs, plates~ blades ~d the li~e, ~rhereb~ tlle tools o~ each
ro~ are placed in an~ular dis~tances ~ro~l each other. ~he rows
o~ the tools of ~oth millin~ clisLs 29 and~30 are overlapping
a~d departing successively and alternatively from tlle one
~illing disl~ 29 and the other,milling disk 30, so that a row~
of -the stril~ing tools o~ t,he one milling disk is enclosed
in radial distance 'by a ro-~ o~ -the stril~ing tools o~ t~e other
milling disl~ In the presen-t case the millin~ disl~ 30 is
provided with a row 33 of milling and po~ding pins, said
row 33 being enclosed on the outar and in~er side by a row ~1
nnd a row 32 of millinG and poundin~ pin~ of t,he oth~r milling
disk 29. Naturally tha null1ber o~ rows c~ bo variad, ~hereby
it is also possible to let proJect t~o successive ro1Ys of the
same milling dis~.
One o~ the ~entioned milling dis~s is orovided Wit}l
apertures 34 near the cen-tre for the passage o~ the material
trea-ted. The passage aperture is precede~ 'b~ a de~lector and
guide plate 39. In ~ron-t of the, passage aperture 3~ is the
space 3~, for inst~ce a ~unnel, througll ~hicll tlle ma-terial
to be processed is ~ed~ Sealing rings 36 pr,event tllis ma-terial
at the ou$side of the ~illing dis~ 29 ~ro~ b~-passing -the
milling and pounding pins in the rows 31~ 32 and 33 and passing
into the discharge space 38 via *he discharge aperture ~7.
The milling dis~s are enclosed by a casing 40 whicll ca~ be '
opened along the ~lange 40' D " ,
' -- :LO -- , , ,
t ' ',
~3~25El
b
In figure ~ it is made appar~nt by arrows that the
pounding pins are alternately moved in contra-rota~tlon. This
resul-ts in ~ery hi~h impac-t velocities. ~ing to simplieity
tlle i~1er and the outer row 32 and 31 o~ the pins of the
milling disk 2~ are ~igured with a line dotted circle and the
between lyi~g ro~ 33 o~the ~illin~ disl~ 30 ~Jith a line and
two points-circle.
Devices o~ the type described have been l~no~n l'or a long
time. They mostly have in con~lon that -the striking pins exhibit
- cylindrical ~orm~ through lrhich a strong directional scat-ter
results ~or the par-ticles accelerated thereb~ ~or tlle ~urpos~
in accordancè with the invention by contrast a de~ice is
pr~erably suitable ~ith non-cyllnclrical strikin~ ele~ilcnts 7
which is in a position to impart a clirected acceleration to
the particles~
The material is fed in through the space 35 centrally and
axially ancl tal~en up by the suction of the through flow of air
or protective gas and the centrifugal force throu~h the
openings 34 and accelerated out~ards, possibly with the aid
o~ ~a~ blades, whioh ~or lnstance can be disposed on the outer
border o~ one o~ both millin~ disl~s or between the pins '31 on
the milling ~is~ 29. The stream o~ air or protective gas
producing the outward movement can be intensi~ied by means
o~ ~an blades on $he milling dis~s~ Through this it arrives
in the pounding zone of the innermost series o~ pins and
experiences a~ approximately tangential accèleration7 whic~ is
-- 11 -- .
r
,
4~ ~ ~ ~
converted by the next in the outward directiont contra-
rotating set of pins into an opposite, likewise approximately
tangential acceleration. This is repeated from one row of pins
to another, until the particles leave th~ zone of the rotors.
Conditioned by the rotational speed of -the disks and the radii
of the rows of pins 7 impact speeds of from 50 to over 300
meters per second are attained~ The resultant impact energies
of the particles are regulated according to their mass and
according to the resistance which the surro~ding~gas opposes
to their motion. Through variation of the rotational speed it
i.s possible to have an in1uence upon the ef~ect of the
ractionation as we}1 as upon the mechano-ch~nical activation
and the energy bein~ stored up by the particlesO ~7ith regard
to externally perceptible efects of energies so stored9 it
is possible in accordance with the method for desirable
properties to be so optimised that a desired parameter is
cohtinuously controlled and the results of the control are
used for the regulation o the rotational speed and t~us the
acceleration and the ultimate speed of the particles.
This has already been described in Austrian Patent
Specification 334,848 for,the specific case of the treatment
of mud-laden ~luids.
The activation treatment is effected ln that way that
the material to be treated is SUD; ected to a ~nechanical
beating or impact action
o~ preferably 3 to 8 mechanical beats and impact pulses
respectively within a time o 10 2 to 10 3 seconds~
~ 12
., ~,
'~J~
~ 113~2SB
In addition means for preliminary washing9 preliminar~
10tation, main flotation, intermedia-te water removal,
hearth washin~, tub washing, heavy fluid separation7 magnetic
separation, electrostatic separa~ion and the like may be
employed before the disintegrator while means for the re-
flotation, smelting, chemical decomposition etc. may be
- pro~ided after the treatment b~ flotatlon~
~, .
~ - 13 -
Y
,. . . . .
