Note: Descriptions are shown in the official language in which they were submitted.
3 L/~ 43
METEOD FO:R :BACK EXTRACTION OF IN:DIIJM
FROM C)RGANIS: SoL~1ENT P~IAS~:
R~Rr~R~uND OF trH$ l~v t~;N l ION
Th:a ~ invention xelate~; to a Ineth~d of ~ecs:~vering indium
by bac~ extraction ~r ~;~rippi~g from an illdium-con~i n; ng
organic ~ol~ren~ p~ase ~a:~ on an alkyl phosphorl~c acid mono-
al~l e~;ter.
In res::e~ ear~ ~ ~olvent ex~ract:io~ ha~ come in~o u3e
in smelting prc:cess,, and vari~d method~ for recove:ring indium
by the t,lsc:hni~e have hitherto been introduced.
In one method ~3apanese Paten~ ~pplication Publicati4n
No. 148735/1980), an in~lium-ion-containing ~ueous solul~ n
i~ brought into ccntact wi~h an organic ~olvent cont;~in~ng
a~ an extractant a mix~ure o:~ a txi al}cyl phosphite and a
mono- or dialkyl pho~phoxic acid to ~3xtract indium selec-
tiLvely~ and the In-containing oryanic ~ol~rent pha~e thu~
o~tailled 18 contacted with an aqueou~ olution acidifi~d with
hydrol::hloric acid ~o effec~ back extraction of indium the:re-
frs:~mO Th~re are other methsa~ ~"30~rna~ of Japan ~lining I!ld.
A~30c.," 93, lû70 (1977 43 0 pp. 323~3251 which compri~e t:he
~lkeps e)~ e~ctrac~ g indium ~rom an In-con~ ~ n; ng aqueoue
8olu~ t with an organic~ ~o:Lv~nt cont~ining ~ril~utyl pho~-
E3ha~3 (TBP~ as ~he ex~ractan~, and ~hen back extractiIlg
i.ndiuim from ~he resulking organic ~olvent pha~e, u~ing w~ter
as ~he ~ractaIIk~ or ~he ~3tep~ of ex~rac~ing indium fro~
* `
~34~3
an In~con~;~;n;r~g aqueous solu~ion by the u~3e of a t~rtiary
fatty acid a~ an ion~exchange liquid, and carrying vut baek
extraction of the el~nellt from the solvent with hydroch~ oric
acid aæ ~.he ex~rac~an~. Still ano~er propose~l m~hod ~apa-
ne~3e Pat.. ~pp~, Publis: Dlsclo~ure Mo. 148736~1980) consists
in extracting indium from an In-con~;-;n;ng solution acidifiea
wi~h ~ulfuric acid t wlth the aid o~ an organic: ~lv.on~
t;~in~ng di(2-met~lhexyl~pho~l?horic acîd ester (D2E~PA) a~
the extractant, and back-ext.ral::ting indium from the organic
olv~nt ph~se, this tim~ by th~3 ac~ion of hydrochloric or
~ulfuxic acid. Yet another sug~eæ~ed me~hod i~ the same as
the one d~cxibed ilmnedia~ely abc~ve with ~h~ ex~ception
that D2E~IPA i~ replaced hy an alkyl phosphor~ic acid monoalkyl
~ster., Tncluding thoE;e cited a~ove for example, me~hod~
or indium recovery have been l-.nown in the art which gen~rally
compri3e se31ecti~31y extrac:ting indium ~roDn an I~ on~; n~ n~
aqueou~ ~olu~ion, with an organic solvent containing one c)iE
varied extractant~, and back-ex~racting indium from the
organic solvent phase by ~he ac~ion of hydrochloric or sulfuric
acid or o water. Of those me~hod~ ~o far introduced, the
one u3ing alkyï phosphonic acid ~o~o~l kyl e~ex~ ha~ b~en known
to :be p~r ticularly ef f ective .
SU~ OF T~ NV~ Jl I ON
ghe pr~ent irl~rention iS charac~eriæed by ~he u~ o an
aqueo~ solll~ion ~ which con~ain~ h~drs:~chlc: rir ac:id and a
-- 2 --
3~
chloride of a metal 1 e.ns nol~le than indium, as the extractarlt
for the bac:k e~straction in the la~3t~menl:ioned method that
compris~s extraoking indium by the use of an oxganic ;olvent
cont~ i n; ng alkyl phosp~onic acid monoalkyl ~ster a3 the
extractarlt and then back~extracting indium fro~n the organic
sol~en~ phase produced.,
As ~tated abo~re, it is know~ that hydroc:hloric acid i8
u~g~d as the axtrac:tant when back-ex~xacting indium fxom an
organic sol~7ent pha~e corlt~in;ng the ele~ent. The use of
an aqueou~ solu tion con~; n 1 ng not only hydrochloric acid
but also a metal chloride of the type defin~3d above in
accordance with the invention of:Eer~ advantages of reduced
h~drochloric acid consumptiorl fox the back extraction, high
indi~m concentration in the back extrac~ r reusabili~y of the
metal chloride by r~cycling, and ease of purification o~ the
back ex~r~ct.
Other eature~ and advan~ages of the ~nvention will
hecnme apparen~ from ~he ~ollowin~ description ~aken in con~
junction with the accompanying drawingJ
BRIEF DESCRIPTION OF T~E ~WIN~
The single figure is a graph showing changes of indium
SIn) conc~n~rati~n in ~he back ex~xac~s at varied h~dro~hlor-
ic acid concentrations, wh~n an aqueous solution of hydro-
chlorlc ac~a ron~ning sodium chloride was used or when an
aqueou~ solu~ion of o~ly hydrochloric acid was employed as
3 -
the ex tractant in ~he bac~ ex~rac~ion of indium :Erom an In-
containing organic ~olvent pha~e,,
DEql~TT~lF;n DESCIRIPII'ION OP' THE lNv~;N~ oN
In the p.racti~ of ~he in~ ion, ~he ind~ COn~A i n; ng
oxganic: svlvent phase :frs:~m which ~h~3 ~301-slt;e indium i~ tc) b~3
back-~trac~ed is ob~ain~d by hx~r~ging an In-con~ i n i n~
aquaou~ solution into conta~t with an orgarlic solsTent which
contains an alkyl phosphonic acid monoalkyl ester ~xtractant
capable of ~electively ex~racting lndium from thP aqu~ou~
solution~,
An alkyl phosphonic ~cid monoalkyl ester has the foll~w-
ing s~ructural fo~mula~
Il
~ 1 ~ P ~ O~I
O
R~
where ~1 and ~2 r~p~e~ent alkyl groups having fxom 8 to 10
c~rbon at~ms a~d which may be th~ ~me or different.
Exampl~s of 8-carbon alkyl group~ are 2-ethyl-1-hexyl~
4-methyl~l~heptylt l~octyl, 3-eth~l-2 methyl-3~pentyl, and
~he l~ke~
Example~ o~ 9-carbon groupæ ax~ 3,5,5~trim~thy~-3~hexyl~
3~athyl- ~methyl-3-he~ylt l-nonyl, 2-meth~1-2-octyl, and the
Exampl~s ~f lO~carhon groups are isodecyl, l-decyl, 4-
~3 ~3
propyl-4~heptyl, 5~me~hy~ oE~rOpy~ Xyl ~ 3 ~ 7-di.lllÇ3t~y
l~octylg 3-ethyl~3- 05tyl~ zlnd the l~ke.
lypic2l1 example~ lnclude 2-e~hyl l-h~yl phO8phOn:LC acid
msno-2-~h~ hexy~ ester, 3 ~, 5 r 5-~rimethyl~3-hexyl phosphon-
iG acid morlo-3 9 5, 5 ~rime~hyl 3-h~yl ester, i~ode~yl phos-
ph~nic acid mons~ oaecyl es~er, 2 e~hyl l-hexyl phD~phonic
acid mono r3, ~, 5-trimethyl-3-he~cy~ e~ter, 2-e~ h~xyl
phosphoni~ aci d mono~odecyl ~ter, and the like~,
U~uaîly, the extra~tant i~ u~ed af~er dilu~ n wi~h a
organis:: 801~rent ~uc:h as kero~ene ~ alcohol, or the l:Lke.
In accordan~e wi~h ~he invention~ ~an ac:idiiEied aqueous
solution of i ndi~ , prepared ~ leaching an indium con~ i n; n~
raw materi~l with a mineral ac:id ~uch as ~:ulfuric acid, i~
contacted in the usual manner with an orga~ic sol~ent corltain-
~ng one of th~ abovemention~d ex~rac:taxlt~, and the In-contain-
ing organic sol~rent thus obtained i~ contacted with an a~[ueous
solu~ion c:on~ both hydrochloric acid and a chloride o
a me~al less noble than indiuun, ~hu~ achievlng 3:ack e~tract~on
of ~ndium fro~l the organi~ lvent pha~e.
Ex~pl~ o chlorid~ c~ metals 1~ nc:ble th~ indium
which m y be employed in ~e Ibae~k ext3~ac:tion of lndi~ from
th~3 organic ~31ve~ pha~e axe chlorld~s of ~1 k~ 7 ~ me~ J
~uch ~8 ~odi~ chlcar~de~ and po a~ium chlo~ideO and chlo-
riae~ of alkaline earth metals, ~uch as magnesium chloride
a~d ¢als:i~n chloride.,
` :;;
In the method of the invent;ioll the chlo.ride o:f a metal
less noble than indlum i~ u~ed to :Eacilitate the xecovery
of indium ~in the form of InC13) rom ~he back extract in
a sub~equent ~tep of displac:emen~ a~ precipita~io~ with
ZiIlC or all3min~l.
As r~gard~ th~ ~olv~t~ or extractants for u~e in th~
back extxac~ion accoxding ~o this inventiont the concentra-
tion o~ hydrochlori c acid in the aque~us solutivn is desixed
~o range ~Erom abou~ 0,.5 ~o about 5 ~ h~3 metal chloride
give~ better result a; it~; concer~tration increas~, and its
concen~ration may be rai~ed ~o a level clo~ely approaching
~he satuxation æolubility. There i~ no ~pecial l~itat:ion
to the contact ratio of ~he organic ~olven~ pha~e (O) to ~h~
aqu~ous ex~ractant phase (~), i. e., O/A, but a ratio in the
range of 1/5 to 10/1 give~ good resul~. ~he contac~ tempera
ture iL.~ ;uch that, wher~as the applica~ion o~ hea~ i~ e~fec:~
ti~e ~ roo~n temperaturQ i~ adequate for practical purposeg .
~he con~ac:t time i~ desixably between n. s and 10 minutes~
Th~ back ex~raction of indium ~rom the organic solv~nt
pha e in c~nformity with ~he in~rention permits the extracted
indium to be recovered in 1;he form of InC13 rom the back
ex~ract~ ~t~3r th~ rec~very o:~ indi~n, ~he metal chloridQ
~n the ~tract is recycle~ for r~u~e as an additi~e in the
proc0~ ~ ba¢k extraetion.
T~st~ we~ ondu~t~d ~:o s~udy the ~ffec~ of the m~3tal
~ 6 ~
chloride pre~:~3nt in the exltractant or the back extractior
u~on the indium cs:~nc~3ntra~ion in the back e~tract. The
result~; are graphi~ally r~presen~ed ill the ac:companying draw~
ing.
The ~est procedurs3 was a~; ~ollows.
Usiny a ~c~lu~ion of 2-e~hyl-l~hexyl 1?hosp}~onic acid
mono-Z- ethyl-l~hexyl e~ter at a concentxation of ~0~ l~y
volume in ker~ene, indium wa~3 extracted from an aqueous
solution of sulfuric acid con~in;rlg the ~lement to obtain
an organic solven~ phase c:on~aining l9.g g o:E indium per
lltqr. Thi~ organic svlvent phase ~0) was brought into
contact with on~ of aqu~ou~ solu~ions (~ of hydrochloric
acid at varied concentratio~s, ~ach cont~;ning 100 ~/~ of
~odium chloride or none a~ all, each in a ratio o~ 0~ = 100
m~20 mQ, and back extraction was carried out, with shaklng~
at ~0C ~or 10 mlnut~s. The vari~ions of the indlum con-
c~ntra~ion in the back extract~ obtain~d w~re determined.
In th~ graph the mea~u~ed co~c~ntrat.ion of hydrochloric
acld in ~he back extrac~ was taken a~ abscissaO
~ s can be seen from the gxaph, the aqueou~ solution o
hydrochloric acld con~;ni~g sodium chloride (MaCl) as a back
extractant mar~edly enhanc~s the back extraction e~ficlency
~ co~pared wi~h the aqueous ~olution o hydrochloric acid
alon~0
Th~ pxe~e~t invention, as de~cxibQd above, m~kss possibl~
-- 7 --
3~3
back extraction of in~ium at a high corlcen tration ~ w an
organic solvenk phase. Addîtion~l advantagi3s are th~3
possibili~y of the metal c:h7 oride added to th~3 extractant
being rec~cled or reuse, and consecl-lent economy on hydxo
c:hloric acid and reduct:ion of cost.
A~ids ~rom these dvan~age~, it i~ wo.rt~ of spacial
men~ion ~hat ~he presen:::e of sodium chloride or the like in
the back extract le:3sens ~he hydrc)chlc~ric acid concerltratiorl,
which is converlient for the sulfidiza~ion, a -~reatment
required to remove tin, arsenlc, and other contaminants which
would increlse in proportions in the hack ext~act with it5
repeated use.
The inventioIl is illus~rated by the ~ llowing examples.
Example 1
With 100 mQ of an organic solven~, prepared by diluting
40 m~ o~ 2~ethyl-1-hexyl pho~phonic acid mono-2~ethyl 1-
hexyl estex" ~ndlum was selecti~Tely extracted from an indium-
Co~ n; ng a~ueous sollltion. The organic solvent pha~e thu;
obtained, cont~;n;ng 14.,~ g S:3e indium per lit2r was sub~cted
to back extract~on in the following way~,
Extractant~ used for ~he ~ack extraction:
~a) ~n aqueous solu~ion con~; ni ng 7~! g o:f h~drochloric
acid and 12~ g of po~assium chloride (KCl) per liter.
(b) An aq~eous 501Ul:iOll con~; n ~ ng 7 ~ g of hydroc}lloric
acid and 95 g of calcium chloride (CaC12~ per liter.
(c) AT1 aqueou~ ~olukion cont;lin~n~J 72 g o:E hydrochloric
acid and ~2 g o magne~i.um chïoride (MgC12) per liter~,
Th organ~c solven~ ph~s~ (C)~ and each aqueous extractan
phase ~A) of khe ~olu~ions ~a~, (b), and ~c~ ~ in an O/A ratio
of 100 mQJ20 mQ~ were ~cept in corltact~ with shaking, at rot~m
~mperature for 10 minute~.. Tabl.e 1 givç~s the results,
For the sake of compari~on arl a~ueous solution contP~in;ng
hydrochloric acia oilly wa~ all~wed ~o con~act a~ an ~xtrac:t-
ant with the organic solven~ phase~. The re~ are al~o
~h~wn in ~he same ~able~.
T a b 1 e
Extractant ~or In co~c. in ~i~3tri~
back extraction back ~xtract bution
~0 ~nQ) tg~Q~ ~~ *
This inventlon:
Extractant (a) 44 . 3 0.13
4 2 . 5 0 . 15
~a) 47.1 0<,11
Comparative example~
~olll~ contg. onLy
HCl 72 g/~ 34 4 0. 23
* Di~tribu~ioll co~fficient -
In concO irl th~3 or~anic solvenlt pha~e
In conc. in the ba k extract
A~ wi:Ll be unders~ood fr~m the ~able, the conc2ntration~of ~indiu~ back-e~z~rac~ed ~ the use o~ ~he aqueous ~;olutions
~L~ag3~3
of hydroehloric ac~d cont;~ ~ n~ ng I~l, CaCl~ J C)X' Mgt::l 2 as
extractants wer~3 higher thall wh~n orlly the aqu ou5 HCl solu-
tion was employ~d~
Example 2
E:ach of the extractant~ mentioned ~elow w~s used in
~electlYely extracting indium frc~n an In~con~ n~ ng aqueou~;
solutioIl,. Each organic solvent phase t~lls obt~; ne~ with ar~
indium s::ontent o~ 0 g/~ wals c~ tacted wi~h an aqueous
solutic~n cont~; n~ ng 72 ~ t>f h~droc:hloric arid and lOG g of
~odium chlorid~ ~NaCl) per li~er, in an O/A ratio o~ 1~0
mQ/20 m~, wit~h ~ha}cing, at roo~n t~nperature fox 10 minutes.
In thi~ way, indium was back-extracted ~rom eac:h organic
801ven~ pha~e.
C~mpo~iti 0~5 o organic ~ol~ent phase~:
~i) For~y mi:Llili~ex~ of 2-ethyl-1-hexyl pho~phonic acid
mono-2-eth~ hexyl ~ster and 10 m~ vf tributyl
phosphate diluted with 50 mQ o kero~ene (to a total
volume o~ 100 mQ~.
(ii) For~y m~ ter~ of 2-ethyl-1-h~xyl phosphonic acid
mono-2 ethyl~l-hexyl e~er diluted with 50 m~ of
kero~ene and 10 mQ of ~ridecyl alcohol (to a total
volume of 100 mQ).
The r~ult~ of the back ex~raction runs were a~ summariz-
ed in ~able 2 By way o c~mpari~on, the results with aque-
OU8 solution~ cont~ n ~ ~g only 72 g of h~drochl~ric ac~d p~r
-- 10 --
liker ~re al~o ~hown,,
A~5 i8 obviou~ fro~n the table, ~e u~;e of a NaCl ~ontai~-
irlg aqueous ~olultion oiE hy~rochloric acid in the baclc sxtrac~
tion of indi~ from an org~ic 80~ ven1; pha ~ leads ~o a high
indi um c:oncerltration ~n ~h~ ~ack exltract.,
T a b 1 e 2
CompoJ3itiorl o~E Extrac~an~ u~ed In conc. Di~ri-
org 1~ 801vo pha~e or back extraction irl back bution
(total lûO mQ~ otal 20 m~3 ~3x O (g/Q) coef:f ~, *
C~mpo~ition (i) ~el 72g/~, NaCl lûOg/Q 42., 5 0.14
~Cl 72 g,~'Q 31~. 9 0. 2~
Compo~ io~51i) EICl 72gfQ, NaCl lOûg/Q 49.4 0.09
~Cl 72 ~Q 38.~ 0.
~ample 3
In the ~ame manner a~ de~cribed in Example 1, an
organic ~olvent phase con~in~ng 17 g of indium per liter
wa~ back-extracted under the condition of O/A ~ 1/1.
Two diff~r~t back extractants, i~e.~ a ~olution con~ ning
~0 g of hydrochloric acid and 1~5 g of ~odium chloride per liter
and a ~olution co~t~in~n~ only hydrochloric acid, were used but
both were adjuæted t~ the ~ame Cl concentratio~ of 148 g~.
~ndex ~he~e condl~io~ he ~wo ~xtrac~ants exhibited ~u~-
~ta~tial~y th~ ~ame back ex~ractab~lity, ~n~ ti~ the
pos~i~ility o ~aCl largely replacing ~ydrochloric acid.
~h~ re~ult~ are ~hown in Table 3~
3~3
T a b 1 2 3
Cl con- Result~ of
Back extract c~ntrxl~, back ~trn~,
~ICl 40 g~ ~ NaCl 125 g/Q 148 g~Q 0.05 ~g~Q orga~ic pha~e)
17 . 7 ~g~Q aqueous phase)
Only ~Cl 1- 0, 06 Ig/R organic phafie~
17 . 7 (y/Q aqueous phase)
