Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
212236~
MEirHOD 0~ PRODUCING AIU~ FROM
AL~6r~ous R~W M~TERIAL
~e ¢h:~ie~l ~ie ld
The present in~e~ion relates to the field of norl-
5 ferrou~ metallurgsT a~d in partiGular deals with a methodof producing alumi:num ~rom aluminous raw material.
BaGk~sround Art
~ t present~ the main ores for production o~ alumin~m
are high-grade low-silicon bau~:ites from which alumina
10 i~ extraGted by the Bayer method, with subsequent reduc-
tion o~ alumirlum by electrolysis o~ cryolite-alumino~s
:~ melts.,
In spite of a number of impro~ements, this method
of producing aluminum by electrolysis of Gryolite-alumi-
nous melts remains energy intensive and doesn~t ¢orres-
pond to modern requirements of environmen~al prot~ction.
~he pr~blem of the source o~ raw materials of the alumina
~ and al~mi~um industry becomes pressing in a number of
; ~ countries with a de~eloped alulainum production irldustry
and po~sessing restricted resources of bau~itic ore~ or
without su~h resource~ at all. ~ great rlumber of in~res-
tigat~ions irl these ~countries is aimed ~t providing le~s
e~r~;y i~ten~ive metho ds o:~ pro du~ing aluminum among
whi~h the most promising is a widely know~ ~hlorination
o~ .al~ or~s and~ electrolyti¢ re~uction o~ the ob-
.tained ~al~m~um ~hloride .
luminum is t~ird in abundance in the Earth' s cru~t
mong all the eleme~ts and first amo~læ metal~ (GoV~VOit~
kevich, O.~.Besso~lo~ "~imichesl~aya evolutsia zemli~ 9
: ~ ; 30 Moscow~"Nedral' Publishing House,1986,p.127) and in the
main aluminum form~ with oxygen a compl~ anio~ ~Al04)5
in a. quaternary ~oordînation and ~orms alumo-oxygen tet-
rahedrons approaching in size silicon-oxygen te-trahedrons
(sio4)4 . Connected wi-th this is mainly paragenetic inter-
~: 35 relation o~ aluminum with silicon in the Earth's crust
and wide occure.n~e of aluminou~ ores - ~aolin clays,
disthene-sillimanite-andalusite slates, etc. .In case of
.. .... .. .. .. .. .. . .. . . ... , .. .... . .. .. . .... ... ~ ... . ... . .. . . .
~ ~ 212236~
-- 2 -- :
providing technolo~ mined economically, co~lntries lead-
i:~g in aluminum production woxll~ be depende:llt upo~ import
o~ bauxite~ and chloride method of electrolysis will allow
to reduce e:~ergg co~sumptio~ ~or aluminum production by
5 35~5%.
Al~o knowIl in the art is a method of producing alu-
minum (U~ ,4,108,7L~1) from ~ ~lec~rol;~e o~ the followi:ng
compo~ition, % by mass 60-87 AlC13, 14-30 NaCl, 5-10 KCl,
0.1~3 .0 mag~esium or calcium chloride. ~he method o~ pro-
10 ducing alumin~m ~rom ~uch an elect;rolyte stipulates condu~-
tion of electrolysis at ~n anode current d~nsity o~ ~.5-
200 Q./dm2, a Gathode current d~nsity of 0~5-200 A/dm ~d a
;~: volta.ge o~ an el~trolytic ~ell of about 2 .7~ 4 V.~fter
: electrolysis th~re is formed a spong~ precipitate co~t~ining
15~ from ~o to 60% by mass of aluminum and slag o~ a complex
composition. Alumin~m is separa~ed from the slag by mel-
ting the precipitate to give an aluminum phase and a
~: phase of a molten slag.
Disad~antages of this method consist in the follow-
20 ing.
U~ed in this method is a scarce reactive - puri-
~ied and dehydrated aluminum chloride~
2. Use is made of a hygroscopic substance AlCl3
found in the open air in ~he form of ~lC13~6H20 (.alwminum
chloride hex~h~drate - ACH) and,therefore, at reduced
~; temperatures of electrolysis in the electrol;yti~ cell i~
the composition of a~precipitate formed are 40-70% by
~; ; : mass of arL u~desirable b~-product (aluminum oxid~). .
3. A proGess of separation of aluminum from the phase
of a molten si~g i~ condu~ted not in a sta~dard electroly-
ti~ cell but on . speGial equipmen~ which in fa~t requires
additional material and energy expenditures.
Also known in the art is a method o~ prod~¢ing alu-
minum from ~uminous raw material, in¢luding treatment of
thi~ raw material, separation of aluminum ¢hloride ~rom
the reaction mass, introduction of aluminum chloride into
a melt of chlorides of alkali metals and subsequent elec-
.
212236~
_ 3 _txolysis of the formed mass to give the end product -
aluminum (GB,A~2,135,66~).
In this method th~re i~ used as aluminous raw matoerial
kaolin ~lay comprising, ~ by mass:
moisture 22~0
~l20~, total 35.0 (dry basis)
Al23, aeeessible 32.2
~e203~ total 1.15 (dry ba~is)
Fe20~, accessible 1.o8.
Treatm~t of this raw material is conducted in
several stages. Firstly, the raw material i5 dried and
: dehydrate~9 and then9it is repeatedly treated with 20-
2~o b~ mass of hydrochlori~ acid at a temperature o~ 60-
110C to give, a~ter settling and ~iltering, a pregnant
liquor Gontaining up to 17.7~o by mass ~lCl3 and up to 0~46~o
b~ ma~ of ir~n~ ~h~ removal o~ alumlnum ma~es up 92%
o~ the lni~lal ma~ of the raw material.
Gaseous Ghlorine is blown through the pregna~t liquor to
¢onverse all Fe2~~ i~to Fe3+, and iron is ~ithdraw~ from
~0 the~liquor making u~e o~ organie liqui~ io~-ex~hanger
( a mixture of decyl al~ohol, kerosine, se~ondary ox
terti~ry high-molecular amine). Purified liquor is sub-
~: je¢ted to evaporation and crystallization to gi~re
lC13~ 6H20 - aluminum chloride hexahydrate. (~CE) whi~h
25 i~ ~al~ined at 450-1,000C,~preferabl~ at 600~750C, to
pro~uce a~i~e alumina possessing a high re~cti~rity"
high Gonte:~t of re~;idual ehlorine arLd ~a lo~.~o~ten~ of
residual hydrogen, The obtained produe~ hlorinated b~ ~
re~gel~ gaseous C12 at~a pressure of from 0~01 to 105 MPa,
30 pre~erably ~rom 0.1 to 0.5 MPa, a3~d at a ~mperature o~
: :~rom 500C to 950C9 preIerably 550-750C" i~ the pre
sence o~ g~eous and solid reducta~ts.
As a result of this multistage treatment, a~hyd-
rous but hygrosGopiG aluminum chloride is introduced
35 into a melt containi~g Ghlorides of GalCiUm or magrLesium~
sodium or 7 ithium.
~ he obtained mass of the following composi~ion,
% b~ mass:
~ 2122~6~ ~
AlC13 2-15
NaC12 or MgCl2 15-17
NaCl or ~iCl 15-8~
is subjected to ele¢trolysis in a mo~o- or bi-pol~r eleG-
trolyti¢ Gell at a temperature of 700C, ~urrent densityo~ 0.5~ m2 with electrode spa¢ing o~ about 1.5 cm.
At the cathode, aluminum i~ deposited and it is siphoned
out of the cell ~or washi~g; at the no~-~onsumable ~arbon
a~ode5 chlorine is discharged and it is colle~ted with
¢ell of~-~asesO
This known method of produ~ing aluminum from alumi-
nous raw material has the following disadvantages~
~ The method stipulates a multistage treatment
: with the use of special acid-resisting equipment capable
to withstand a pressure of up to 1.5 ~a and temperatures
o~ up ~o 950G, as well as the use of ~uch noxio~s sub-
~` stance~ as hydrochloriG acid, gaseous chlorine 7 et~.,
2~, To withdraw iron from the pregnant liquor, u~eis made of s~aree gaseous ehlorine a:~d organi~ liquid
20 ion ex¢hanger (a mixture of de~yl ~l~ohol, kerosine,
se~ondary or tertiary high-mole~ular amine~
3~ Alumi~um ~hloride produced a~eoxding to this
m~thod i~ hygroseopi~; there~oregit i~ u~suitable for
storag~ and transportatio~ and reguire~ immediate use
25 irl the el~trol~tic process~ For ~hi~ reaso~,alumin~m
hloride produetio~ m~st be dispo~ed alo~gside ele~tro- :
l;srti c b~th~ O
4.~hydrou~ d ;yet hygros~opi~ aluminum ~hloride
in the proeess o~ dissolving i:~ the ~lectrolyti~ melt
30 ~hanges ~omposition of the latter leading to an increa~e
, i
of ~urrent utilization fa~tor and, aGcordingly, to
in~reased energy consumption in the proees~ for aluminum
produGtion. Liberation of gaseou hlorine at the ~node
also promotes changing of the eleGtrolyti¢ melt compo-
~5 sition.
Disclosure of the Invention
The present inve~tion is based on the problem to
provide a method of producing aluminum from aluminous
21~23~i4
5 --
raw material by way of simpli~ying the te~nology.
This problem i~ ~ol~ed by that in a m~thod inG-
luding treatme~t of this raw material, separation
~rom the obtai~ed reaetion mass of a produ~t ~ontaining
5 aluminum ¢hloride, its introduction into a melt o~
alkali metals ~hlorides, and then electrolysis o~ the
obtained ma~s to produce the end produ~t, in which,
according to the invention, treatment of the aluminous
raw material is per~ormed in a sin~le stage with a mix-
ture o~ alkali metals salts of fluorine-containin~ oxy-
gen-free a~d hydrochlorie acids taken, respeGtively, in
a xatio of from 5:1 to 1:7.5 parts by mass, in doing so
th~ aforesaid mixture o~ salts i~ introduced in amount
of 40-85% of the total mass and the pro¢ess o~ treatment
is conducted at a temperature o~ 850-1,100C till ~orma~
tion of the reaction mass consisting .of immis~ible ~luo-
ride-silicate and ~hloride-alumina~e alkaline melts, as
a ~rodu~t ¢ontaining aluminum chloride ~rom this reaction
ma~ separated i~ chloride-aluminate alkaline m~lt, and
ele~trol~is is condu~ted at a temperature o~ 720-800Co
In doing so, as aluminous raw material it i~ desir-
able to use di~the~e-sillimanite-andalusite concentrate or
~uo~ide-silicate melt.
: It is recommended to cond~t the pro¢ess of ~reati~g
alu~inous raw material with a mixture of alkali metals
salt~ of fluorine-containing oxygen-~ree and h~droch70ric
acid~ at a temperature of 870-950C,
~ he method of the present inve~tion allows to pro-
du~e aluminum ~rom aluminous raw material a~cording to a
simplified technolog~ as it stipulates a single-stage
treatment of aluminous ra~ material ~o obtain a product
~ontaining aluminum chloride without employme~t of a
special a~id resisting equipment.
I~ the process of treatment, iron is concen~rated
in the ~luoride-silicate melt and effecti~e purifi~ation
o the ¢hloride-aluminate alk~line melt takes pla~e
whi ch doesn ~t require employmen~ of a special equip~ent
~, 2:1223~1
and additional ~onsumption o~ s¢ar~e components.
~he product produ~ed by the method o~ the prese:llt
inve~ion arLd ~ontairling aluminum chloride ( chloride-
aluminate alkaline mel~) is not h;ygros~opi~ this ~ol~-
ne~tion7it ~arl be stored and transported WhiCh allo~ o
obviate the need to locate production of the produet com-
prising aluminum chloride ,in the vicinity of electrolyti~
baths .
Chloride-alumina~e alkaline melts approa~h in ~omposi-
tion electrolytic melt of alkali metals chlorides; therefore,
~:, their direct introduction changes electrolyte ¢omposition
at a mi~imum. The la~ter results in a high ~urrent u~iliza~
~: tion ~actor and5 correspondingl~, in redu¢ed energy ~onsump-
tion i~ the pro~eSs of aluminum productio~. Minimal ~hange
15' of the electrolyte compositîon is also ~nhanced by the rea~-
;~ tion of ¢hloride with sodium a~d potaSsium o~{ides and in~on-
siderable discharge of` chlorine gas into th~ atmosphere.
Besides, instead o~ noxious gaseous and liquid subs-
tance~ (:h;ydro¢hloriG aeid, chlorine gas, etc), the method
of the ir~vention in¢orporates the use o~ more safe solid
lkali metals salts o~ fluorinè-containing oxygen-free a:~d
hydrochloric a~ids . ~hiS fact also, allows ~o simpli:f~y signi-
iean~l~ equipment :Eor the pro~eSS of treatment of alu~i-
OU3 raw: material .: :
~he method~ of th~ srention is realized as foliowsO
Aluminous raw~material is subje~ted to treatment with
a mixture o~ alkaii metals salts of fluorine-containing. ox~- -
,~; gen-free and h~drochloric aGids.
o do this, using . standard equipment, aluminous
30 material is added with a mi~{ture of alkali metals salts of.
fluorine-co~taining oxygen-free a~d hydroçhloriG a~id~
:: taken in a ratio of ~rom 5:1 to 1:7.5 parts by m~ss, res-
peetively, and the aforesaid mi:~ture of salts is taken in
amount of 40 85% of the total mass; the pro~ess of trea~-
ment being ~onducted in an ele~tric f~arn~e at 770-1 ,100C3
~: . preferabl~ at 870-950C, U:lltil aLL i~ni~cible fluo-
ride-silicate (I) melt and chloride-aluminate alkaline (II)
melt containing 9~ ,~ by mass of aluminum chloride are
.
.
~ ;l 212236~
-- 7 --
ob~ai~d,,
In this Gase 9 as ~n alkali metal salt c)f . oxygen-
fr~e :fluoroae~d, use ~a~ be made of, ~or e~ample, K2SiF6,
~a2Si:F69 Na3~1~6~ NaF, al:ld as aluminou~ raw materia~
5 use Gal:l be made of, in parti6ular, dehydrated kaolin con-
~entr~te of the following composition, % by mass:
SiO2 5~ - 60
23 37 4~
~e203 0.5 - 1.2
! TiO2 0.4 - o.8
N~20 0.1 - 0.3
K20 1.2 - 1.8,
: ~ ~ or di~the:ne-sillimanite~a~dalusite co~centrate of the fol-
lowin~ composition, ~ by mass:
~i2 36 - 42
~l203 55 - 61
e20~; o.6 - 1.5
TiO2 01~4-- 1.2
:
Na20 0.2 - o.8
2() : K20 0.1 - 0~,6,
a~ well a~ ~northosites" sy~erites, nephel'na syenites,
m~eral part of coal ash a~d other aluminous raw material.
In case use i~ made o~ a mi~t~}re of alkali met~ls
: æalts of- fluorine-~o:r~t~ ing oxygen-free a~d hydrochlori¢
~cids9 ra~io of ~hese saIts beI~g respecti~el~ more than
~: - 5:1:or less than 1:7.5; the a~oresaid pro~ess gi~es ~ homo-
ge~eou~:melt.
the quantity of the mixture of alkali metals salts
o~ ~luorin~-containing oxygen-~ree and h~dro~hlori~ aeids
30. i~ le~s than 40~0 or more than 85~o of the total reaction
mass, the process also results in formation o~ a homoge-
neou~ melt.
Condueting the pro~ess at a temperature below 850C
;~ glve~ a rea¢tion mass ~onsisting of lens-like or ball-lik~
inGlusions o~ fluoride~ ate melt in the chloride~alumi-
nate alkaline melt or analogous in~lusions OI ~hloride-
alumiilate alkali:lle melt in the fluoride-siliç~ate melt.Sueh
; ~
- 8 _ 212~6~
a m~ur~ i5 0~ limited utilîty for mechaniGal sepa-
ration of the formed immis~ible melts.
Condu6ting the process at a temperature above
1,100C results in the fact that considerable amounts
(more than 3.70~ oP the total reaction mass) .of fluo-
rides o~ alkali metals and other volatile ~omponentæ
vola~ize~
Besides, a need is generated for increasin~ ener-
gy consumption to at~ain and maintain such high-tempe-
ra~ure conditions.
Per~orming the process of the a~orementionedtreatm~nt of aluminous raw material wi~h a mixt~re of
alkali metals salts of ~luorine~containing oxygen-free
and hydrochloric acids at a temperature of 870-950C
is ~referable,and this results in ~ormation of a well-
defined two-layer texture of immiscible melts: ~luoride-
silicate melt (I~ and chloride-aluminate alkaline melt
(II). Su~h texture is suitable for mechanical separation
of immisGible melts:in the process of and a~ter treat-
men-~ o~ aluminous raw material.
: ~ In doing so, the fluoride-silicate melt (I3 comp-
rises, % by mass:
23 ~ ~ 17 32
SiO2 : 18 - 50
NaCl 1 - 3
K2SiF6 4 43
o 4
Na2SiF6 .~or NaF 0 - 21
~a20 0 - 7,
~0 and chloride-aluminate alkaline melt (II~ comprise~, %
by mass:
AlCl3 9 - 40
~aal 8 - 71
Kal 8 - 48
- 35 Na2siF6 0 . 5 - 3
NaF or K~ 5 - 32
Na 0 3 - 6.
. _ .
`. 9 212~3~ll
The obtained chloride-aluminate alkaline melt ~ II)
is separ~ted ~:rom the reaction mass and introduced inlto
a melt of alkali metals chlorides, after whi~h the ob-
tained mass comprising components in the followi~g
ratio, % by mass:
3 0~5 - 5.0
NaCl .45 0 ~ 75 0
gCl 20.0 - 45~0
NaF or KF 1 - 10.0
Na20 or K20 Q 0
is subjected to electrolysis in a graphite cell while
the fluoride-silica~e melt (I) is directed for a multi-
:stage treatmen~ using it as an aluminous raw material.
In doing so, alumi~um extraction makes up 88-93% of the
mass thereof in the initial aluminous raw material.
Sili.ceous concentrate remained after repeated treatment
may be used in various branches of industry ~ for produ¢-
~:~tion o~ silicate materials, ~or manufacture o~ package
glass, as an adsorbent ,for oil produGts a~d ~or other
p~rpo~es)~ besid~s, it is ~ologic~lly safe produstO
~:E~ectrolysis is conducted in a graphite mono- or
:~ .bi-polar electrolytic cell at a temperature o~ 720 -
800t~C ~ preferably at` 740-780C), G~Lrrent density o~
005-3 A/sm with ele¢trode spa~ing o~ 0.5-1 cm till ~or-
~:25 mati.on o~ the end product: - aluminum at the cathode.
In ~a~e of condu~ting electrolysis at a tempera-
ture above 800C~ evaporation of the melt increas~s,
anode corrodes at the air-melt boundar~-a~d, i~- ~oi~g 80
electrol~te is severely contaminated with graphite.
In Gase the temperature OI conducting electrolysis
is below 720C, it is difficult to main~ain thermal
balan¢e irl the cell due to considerable viscosity o~
the melt 7 its sti¢kir~g to the graphite anode, decreased
are<~ o~ the active anode zone or complete s~tting of
35 the electrolytiG melt~
The obtained product - aluminum is removed from
the cell, collected ~or casting and a~Lalyzed. :1~ this
21223G4
- 10 -
case, ~h~ degree of purity of alumi~m îs from 98.7-
99~3%. The obtained alumi~um is direGted for ~urther
utilization i~ various branches of industry.
Chlorine ga~ discharged at the anode reaets with
5 oxides of sodi~am and potassium,,60ncentration o~ whi~h
is de¢reased practically to zero wh~re ,l~ doi~g ~o~ formed
are ~odium and potassium ~hlorides whi~h are fed to
the ele~trolytic eell~ Thus, minimum dis~harge o~ gas-
eous ¢hlorine into t~e a~mosphere takes pla~e; this
fa~t ensuring inconsiderable Ghanges in the electrolyte
c3mposition and enhan~ing to m~intain stable electri¢
co~duetivity o~ the electrolyte.
For a better understanding of the pres~nt in~en-
tion~ given below are the follo~ing examples not limiting
the s¢ope of the invention.
Example 1
he method o~ the in~ention is realized as ~ollowæ.
n amou~t o~ 30 g o~ dehydrated ~aolin concent-
ra~e ar~ treated with a mixtur~ of potassium Ghloride ~50 g)
a~d ~ drite - ~2SiF6 (~0 g) in ~n ele~ric furna~e at
`~ a temperature of 900C i~ the cour~e o~ 1.5 hour~ ~s a
~; res~l~ o~ meltin~ there are produced two i~mîsGible melt~
o~-a two-layer ~eYture: 44.75 g (45%) of fluorid~-sili¢ate
melt (I) of the following compositio~ % by mass~
Al203 16.63
i2 45-~4
aCl 1.81
32.82
NaF 1.22
~a20 1.68,
and 54.69 g (55%) of chloride-aluminate alkaline melt
(II) of ~he ~ollowing composition, ~0 by mass:
AlCl~ 22.13
N~Cl
~5 KCl 42.28
~oti¢@: Tn all Examples data of the chemical analysis
are calculated for 10C~o,
'` . 212236ll .
Na2~i~6 0.94
KF 22.59
Na2~ 4.32,
After meltin~weight lo~ses amount ~p to 0.56%
o~ the Initial reaction ma~s.
~he ob~ained chloride-al1~m;nate alkaline melt
(II) is separated ~rom the reaction mass a~d t~e remained
~luoride-silicate melt (I) (~.75 g) is again directed
~or treatment as an i~itial aluminous raw material. Alu-
minum extraction degree makes up 93% of it~ mass in the
ini~ial dehydrated kaolin concentrate~
Chloride-aluminate alkaline melt (II~ ~s added
~1/4 part by mass) into a gxaphite ~ell filled (3~4 parts
b~ m~s) with electrolytic melt of alkali metals ~hlv-
rides9 NaCl to KCl ratio being egual to 2~5:1.
:: Initial composition of the ele~trolyte~ % by
: mas~:
AlC13 5.,47
: NaCl 57,98
KCl 29 o 10
: ~a2SiF6 0 . 26
KF 5 0 51
K20 1 . 68 ,,
EX*raation o~ aluminum is performed at a te~pe~
~5 rature o~ 760a a~d current density of 1~5 A/~m2. ~ter4 hour~ o~ ele¢trolysis, 1/4 part of the electrolyte is
discharged and a new portion of the melt II i~ added~
: ~inal composition of the electrolyte, % by mass:
AlC13 0.61
NaCl 61,76
KC1 31 .49
2siF6 o ~13
~F 6 ., 01,
The dis~harged melt is utilized again :or treat-
35 ment of dehydrated kaolin concentrate.
As a result of electrolysis, ab the bottom of
the graphite cell there is formed. a layer o~ aluminum w~ ch
.
2122~
- 12 -
is removed from the.cell, analyzed (purity degree makes
up 99.3%) and colle~ted for casting.
In the process of electrolysis, ~hlorine generated
at the anode rea~ts with potassium oxide to give, as a
result of this reaction, potassium chloride which is fed
to the electrolytic cell~ Thus, practically eliminated is
the discharge of gaseous chlorine into the atmosphere.
Example 2
~he ~ethod o~ the invention is realized in a man-
ner similar ~o that of Example 1. 15 g o~ disthene con-
centrate are treated~with a mi~ture of sodium chloride
~ (75 g~ and hieratite - K2Si~&(10 g) in an electric fur-
: nace at a te~perature of 950 C in the course o~ 1.5 hours.
As a result of me:lting, ~here ~r~ obtained two immi~ible melts
of a two-layer tex~ure: 19.88 g (20~o) of fluoride-sili-
Gate melt (I) of the following composition, % by mass:
Ql203 31.17
SiO2 42.02
NaCl 2.~1
~2~iF6 4.16
NaF ~ 20.34,
d 79.50 g (80~0):0f.~hloride-aluminate alkaline melt
: (II) of the following composition, % b~ mass:
lC13 :~ . 10~3~
25~ NaCl ~ 71.14
KCl ~ ; 7.91
Na SiF6 0056
: :Na~ : 6~10
: ~a20 3.94.
A~ter melti~g, weight losses amount up to 0~62~o
: o~ the initial rea~tion mass~
he obtained chloride-aluminate alkaline melt
II) is separ~ted from the reaGtio~ mass and th~ remained
~ fluoride-silicate melt (I) ~19.88 g) is again direGted ~or
:;: 35 trea*ment as an initial aluminous raw material. ExtraG-
~ tion degree of aluminum makes up 90~0 of its mass in the
:: initial disthene concentrateO
: 21~23ti~
- 13 - ~
Chloride-aluminate alkaline melt (II) is intro-
duced (50~ by mass) i~to a graphite cell ~illea (50~0
b~ mass) with electrolytic melt of c~lkali metals chlo-
rides, NaCl to KCl ratio being equal to 1.5:1.
I~itial composition of the electrolyte, ~ by
mass:
~1~13 5.20
NaCl 65.89
KCl 23.85
:~ ~ 10 Na~SiF6 0~34
~a~ 2.86
Na20 1.86.
Extraction of aluminu~ is perfo~med at a tempera-
~ure of 720~ and current density of 3 4tcm2. After
4 hour~ of electrolysis, 50% of the electrolyte are
remo~ed a~d a new portion o-~ the melt II is introduced.
Final composition o~ the elec~rolyte, % by mass:
lC13 0.53
NaCl 71.52
~0 ECl 2~.59
2si~6 0.13
:Na~ 3.23.
The removed melt is utilized again for treatment
: : o~ disthene concen~rateO
~s a result o~ electrolysis, at the bottom of
he graphite ~ell the~e is ~rmed a layer o~ aluminum v~ieh
i scharged ~rom the cell, c~nal~zed (purity degree
makes:up 98.9%) and collected *or casting.
Chlorine ~generated in the process o~ electrolysis
reacts with sodium oxide wh~ thc la~t~r i~ trarl~fo~m~d
i~to sodium chloride whiGh is fed to the eleGtrolytic
cell. In this case, practically eliminated is the di~¢harge
o gaseous chlorine into the atmosphere.
Example 3
The method of the invention is realized in a man-
ner similar to that o~ Example 1. In this case~ 60 g
of dehydrated kaolin concentrate are treated with a
. 1
_ 14 - 2l22~6~
mixture o~ potassium chloride (20 g) and eryolite -
Na3AlF6 (20 g) in a~ electric ~urnace at a temperature
o~ 1,100C in the course of 1 hour,
As a result of melting,there ~r~ .Q~i~ed.~wo immi~-
cible melts o~ a ~wo-layer texture: 81.86 g, ~85%) o~
fluoride-sili~ate melt (I) of the following composi-
: tion, % by mass:
Al~03 31.62
SiO2 36.23
NaCl 3.~9
: K2siF6 23.00
:~ Na20 ~ 5.76,
a~d 14.44 g (15%) of c~Ioride-aluminate alkaline melt
(II) of the following composition, ~, by mass:
: AlC13 40.13
aCl 12.34
KCl ; 26.73
Na2Si~6 ~ : 2.99
:: KF 11.51
ZO I~a20 6.30.
t~r melting~,~weight losses amount up to ~ .70yO
of the initial reaction mass.
he obtained Ghloride-aluminate alkaline melt
(II) îs separat~e~d~from the ~rea~tion mass and the remained
2 5 ~luoride-silicate~ melt (I) (81 .86 g) is again dire~ted
or treatment as~a~ initial aluminous raw material.
~ ~ ,
x~ra~tion degree~of aluminum makes up 92% o~ it~ mass
:ln the i~itial kaolin eo~centrate.
Chloride-aluminate alkali~e melt (II) (12.5% by
ma~s) is introduced into a graphite cell filled (87,5%
by mass) with electrolytic melt of alkali metals chlo-
~ .
rides, NaCl to KCl ratio being equal to 3:1.
I~itial composition of the electrolyte, % bymass:
~: ~ 35 AlCl3 5 . 06
; NaCl 6~ . 92
::
.
212236~
- 15 - -
ECl 23.03
N~2SiF6 0.3
EE 1.4~
K20 1.22.
Extra~tion o~ alumi~um is performed at a temperature
of 800C and Gurre~t de~sity of 0.5 A/cm2. ~fter 4 hours
o~ ele~trolysis, 1/8 part of the electrolyti~ melt is
removed,and a new portion of the melt II is introduced.
Dis~harged melt is utilized again ~or treatme~t of
dehydrated kaoli~ concentrate.
Final ~omposi:tion of the electrolyte 9 % by mass:
~lC13 0.58
NaCl 72.70
KCl 24.82
'l5 ~a2SiF6 0.13
KF 1.774
~ ~s a result of electrolysis, at the bottom of the
: ~ graphite cell ~here i$ ~ormed a layer of aluminum~ h ~s
~: dischar~ed from the cell~ analyzed (purity degree make~
up 99.1~) and collected for casting.
Chlorine discharged at the anode reacts with potas-
: sium oæide, conce~tration of which reduces from 1.22% to
zero9 in this ¢asegpotassium chloride is formed,a~d it
is :l~ed to the electrolytiG cell~, Thus, minimal discharge
of ga~eou~ ~hlori~e into the.atmosphere takes place.: Example 4
~ . The method o~ the invention is realized in a man-
:~ ner similar to that of Example 1, but in thiæ Gase~40 g
o~ disthene conce~rate are treated with a mIxture of
sodium chloride (10 g) and hieratite - K2Si~6 (50 ~) i~
an electric furna e at a temperature of 800C in the
course o~ 2 hours.
As a result of melting, ther~ are obtained two immi~-
cible melts o~ a -two-layer texture: 84.50 g (85~) o~
fluori~e-silicate melt (I) of the ollowing composition,
% by mass:
: Al2o3 27.23
- ~ ` 21223G4
- 16 -
Si~2 17 . 75
NaCl o,69
K2SiF6 43~12~
Na2Si:F6 11 . 05,
and 14.91 g (15%) of chloride-alumi~ate al~aline melt (II)
of the ollowing composition9 % by mass:
~1~13 32.11
MaCl 9 3,9
KCl 17.58
l~a2SiF6 2.78
~ 31 . 79
Na20 6.35.
~ fter melting, weight losses amount up to 0059% of
the initial reaction mass.
~he obt~ined chloride-aluminate alkaline melt (II)
is ~eparated ~rom the reaction mass and the rema~ned ~lu~-
ride-silicate melt (I) (84~50 g) is agai~ directed ~or
treatment as an i~itial a1umi~ous raw materialc Extrac-
; tiOll degree of aluminum makes up 8~% of its mass in the
20 i~tial. disthene conGentra~e.
~ Chloride-aluminate alkaline melt (II) ~1/6 part by
;:~ mass) is Int~oduGed i~to a graphite cell filled (5/6 part
~; ~ by mass):wi~h electrolytic melt of alkali metal~ ~hlorides,
NaCl to ECl ratio being equal to 5:10
; ; : 25 Initial Gomposition of the electrolyte, ~ by mass:
lC13 5.3~
~: : NaCl 65.59
Cl 23.70
~a2Si~6 0.38
~0 NaF 3~95
~a20 1~05-
: Extra~tion of aluminum is performed at a temperature
o~ '740C and current density of 2 A/cm2. ~ter 4 hours of
electrolysis 3 1/6 part o~ the electrol~te is remo~ed and
a new portion of the melt (II) is introdu~ed~
~inal composition o~ the electrolyte, % by mass:
C 3
- 17 - 2l22~64
NaCl 70 3~
KCl 24~58
Na2SiF6 0.13
NaF 4037.
DisGharged melt is utilized again for treatment
o~ disthene concentrate.
As a result of ele¢trolysis, at the bottom of the
graphite cell there is ~ormed a layer of aluminum, ~Jhi¢h i5
di~charged ~rom the cell, analyzed (purity degree makes
up 98.7%) and collected ~or casting.
In the process o~ electrolysis, ~hlorine genera~ed
at the a~ode reacts vtith sodium oxide. ~s a result of
this process~ sodium chloride is formed a~d i~ is fed
to the electrolytic cell.~hus, practically eliminated
is discharge of gaseous chlorine into the atmosphere.
E~ample 5
-~ The method of the in~entio~ is realized in a ~an-
ner similar to that of Example 19 but in this ca~e, 15 g
o~ dehydrated kaolin conce~trate are treated with a miY-
:20 ture of potassium ehloride (65 g) and villiaumi~e - NaF
(20 g) in ~n electric ~urnace at a temperature o~ 870C
I~ the course of 2 hours.
: As a result of melting,~he~e ære ob~ained bwo immis-
cible melts of à two-layer texture: 19~90 g (20~) of
~luoride-~ilicate melt (I) o~ the ~ollowing ~omposition,
% by mass:
~l203 16.75
SiV2 39 e8~
NaCl 1.24
: ~0 K2~i~6 3-99
KF 3-~5
Na20 7.~2 5
and 79.59 g (80~o) 0~ chloride-aluminate alkaline melt
(II) o~ the following composition, % by mass:
AlCl3 8.97
NaCl 16.42
KCl 47069
~ 212236~
,
~ 18 _
N ~iF 45
KF 20.13
Na20 6,34.
A~ter melting, weight losses amount up to 0.51%
of the initial rea~*io~ massO
The obtained chloride-aluminate alkaline melt ~II)
is separat~d from the reaction mass and the remai~ed
~luoride~silicate mel~ ~I) (19.90 g) is agai~ ~irected
for treatment as an initial aluminous raw matexial.
Extraction degree of aluminum makes u~ 92% of its mass
in the i~itial dehydrated kaolin co~centrate .
Ghloride -aluminat e alkaline melt (II) (55% b~ mass)
: is introduced i~to a graphite cell filled ~45% by mass)
with ele~trol~srtic melt o~ alkali me-tals ~hlorides ~ ~aal
to KCl rat~o being equal to 1.5:1.
I~itial ~omposition o~ the electrol~teg ~0 b~ mass:
AlC~ 4~94
~aal 41.67
KCl 38~9
~a2Si~6 ~21
10.27
.
~2 4.01
. Extraction of aluminum is performed at a tempera-
~; tu~e o~ 780C and Gurre~t de~si~y o~ m2~ B~ter
4 ~our~ oX electrolysis, 55% o~ the ele~troly~e ~e
xemo~ed and a new portio~ of the melt II i~ IntroduGed.
FInal Gomposi~ion of t~e eleGtrolgte, % by mass:
lC13 0.53
NaCl 45078
. 30 . ~Cl 42.88
: ~ ~a2si~6 o.o8
. ~F : 10073~
Dis~harged melt is again utilized for treatme~t
: of dehydrated kaolin eo~Gentrate~
~ a resul~ of electrolysis, a~ the bottom o~ the
graphite ~ell th~re ls formed a lay~r o~ alumî~um~which i~
removed ~rom the cell, analyzed (purity degree makes J
,,. ,~ - r
21223~
- 19 -
up 99.2%) ~nd collested for casti~
Chlor~ne genLerated i:ll the process o~ ele~trolysi~
reacts with pota~;sium oxide to trans~orm the latter to
potassium ~hloride whi~h is ~ed to the ele~trolyti~ ~ell.
5 In this case, pra~ti:Gally elimirlated i~; th~ ha3~g~ ~f
~;aseous chlori~e into the atmospherel,
Industri;al Applicability
~ he i~lventio~ Garl ~ d a~?plication in various
: bra~lches o~ industr~ dealing with productio~. and ~tili-
~: '10 zatio~ of aluminum.
~;
~ ~ .
,~ '
.
.~
:
.
,
:
~ ~ . ,.. . .. ....... ., .,. ., ., .. .. , ~ . , j .. .. , .. ; ".. .... ...... ..... ... . . .. . .. . . . . ... .... . .. ... .... .
