United States Patent [191
[11]
4,082,832
Watanabe et al.
[45]
Apr. 4, 1978
[56]
[54] TREATMENT OF RAW MATERIALS
CONTAINING TITANIUM
References Cited
U.S. PATENT DOCUMENTS
Morio Watanabe, Arnagasaki; Sanii
Nishimura, Kyoto, both of Japan
3,025,135
3/1962
Kenworthy
.
423/70
3,067,010
12/ 1962
Long et a],
423/ 70
3,479,378
3,725,527
11/1969
4/1973
Orlandini .... ..
Yamamura ...... ..
423/49
423/70
[73] Assignee: Solex Research Corporation, Osaka,
3,875,285
3,976,475
4/1975
8/1976
[75]
Inventors:
Japan
Nyman ............ ..
423/54
Markland ............................. .. 423/ 63
FOREIGN PATENT DOCUMENTS
[21] Appl. No.: 680,928
[22] Filed:
[30]
970,885
9/1964
United Kingdom ................. ., 423/70
Primary Examiner-O. R. Vertiz
Apr. 27, 1976
Assistant Examiner~Brian E. Hearn
Attorney, Agent, or Firm—Toren, McGeady and Stanger
Foreign Application Priority Data
May 6, 1975
Jul. 21, 1975
Japan ................................ .. 50-55048
Japan
.................... .. 50-89433
Dec. 4, 1975
Japan
Jan. 16, 1976
Japan .................................. .. 51-3939
50-144861
[57]
ABSTRACT
Production of titanium dioxide which is characterized
by recovery of reusable H2804, highly pure Fe oxide
and hydroxide and fractional recovery of Mn, V and
Cr, etc., from FeSO4. nHzO and waste acid of 20 — 40%
[51]
Int. Cl.2 ................................. .. C01G 23/04
[52]
US. Cl. ...................................... .. 423/70; 423/49;
H2SO4 containing abundant heavy metallic ions, which
are by-produced in the production of TiO; by dissolu
423/54; 423/63; 423/ 82; 423/ 85; 423/139;
423/146; 423/531; 423/616
tion slag, such as electric furnace slag, convertor slag
[58]
tion of Ti raw materials such as ilmenite, steel produc
H2804.
Field of Search ..................... .. 423/49, 54, 63, 70,
423/82, 85, 139, 558, 615, 616, 531; 75/101 R,
7 Claims, 20 Drawing Figures
101 BB, 121
(H2804) STRUNG Mill]
mnvmwiiiiism ura'sm'p
ncmmsm
EVA
I
with n
F___
1mm REBUVERY Nb W “Mi
HLTRA lllN
Pnnnumnm
A “3mm”
DISSDLVE
l
l
I
[H2618
f
5
@1110“
l REBIIVERV
l
(numsm
l
l
'--_-J
I
H2804
if"
mm
I
I
rwsmw] {men n l lures“ sum
M in,‘ . iii-“Him
?rg (E)
1 '
DIAPHRAGM
ELEBTRULYSIS
Hill
MM12
UXIDATIUN
Fellllll SEPlRlTE
US. Patent
April 4, 1978
Sheet2 of11
4,082,832
F562
Fe804-nH20
WATER
DISSULVE
02am
'
i
“"1
I
__] mg“? i
nxmmun
I
Mn804 Pnnnum
} Mn“STRlP
l
Fe3+ EX
Fe“ STRIP
HFeBIA Ex
REIIUVERV H2804 H
kI
DIAPHRAGM
ELEGTHULYSIS
w H
in
0' GENE A H
MB
—______|
i
OXIDATION
Fe? 03
US. Patent
April 491978
Sheet 3 0f11
4,082,832
F l 6.3
20'
Nb EXTRAGTIUN mumsmum
g
mmmc PRIMENE JM-T 10%
5
PHASE
UGTANUL
5%
mum WITH KERUSENE
,
AQUEOUS
A _
FREE ABII) (mam) M
PHASE
=5
'
m
‘"7
1
[Nb2051Aq
F l (3.4
0r“ EXTRABTIUN EQUILIBRIUM
nnsnmc PRIMENE MM 10%
PHASE 00mm
5%
5
‘(-25
‘J
2'0
'
(g/l)
°
DILUTEI] WITH
5_
KERUSENE
AQUEOUS Fe“ n
PHASE ‘mm swam am
A 3}“:
_
FREE msm 0.1m
a
0'2
0'4
0'6
a0
US. Patent
April 4, 1978
Sheet4 ofll
4,082,832
F I G.
0r“ BARK EIITRIIGTIIIN AND ACID cuucmmmnre
/
I%)EBIAI TI N
1'
I
HGI
°—-—-° I-IEI SHIIIINII IUIIIIN
X--——x H2304 SIIIIIIINII IIIIIIIII
I.
(N)
I
H284
5
(II)
F 60%
20—
III‘3+ EIII'IIIIIIIIIIII EQUILIBRIUM
<84)
ammo
PHASE
so % MEI-IPA
5% um'mem
mumn WITH KERIISENE
AQUEOUS
30W H2304 (FIIEE)
1
[Gr3
Pg 0-
°
PHASE
US. Patent
April 4, 1978
Sheet 7 of 11
4,082,832
FlG.ll
HEeIIII EIIIHAUTIUN EIIUILIBIIIUH
UHHAHII} PHASE W 75% x—x
IIIIUTEI] WITH KEHUSEHE
0-0
mp 15% D_u
IuuEnus PHASE FREE H2804 I?UJg/I x-x
EnEE mam 215.5% 0-0
EFEHIAq (2/1)
F I 6.12
EBUII EIITIIAIIIIIIH EQUILIBRIUM
IIIIIIAHIU PHIISE 15% TBA IIUTAHUI 5% IIIIUIEII WITH KEIIUSENE
(g/l
)
O
[FeI lrg
"
°
@
K
IuuEnus PHASE FREE msm 1608/1 x
FREE mam 2158/1 ~—-°
II)
2H
25
ah
US. Patent
April 4, 1978
m_
Sheet9 0f11
4,082,832
F1615
V5+ EXTRMITIUN EQUILIBRIUM
URGANIB
15% TIUMH
5% UBTANIIL
PHASE
DILlITED WITH
u
A
"
KEHUSENE
mumus
FREE H284 3008/1
_
PHASE
5}:
'.
‘
'
“‘ [W1 Aq
'
'
(8/0
0'2
'
'
'
'13
F l G. 16
1001
_
v
,_
PH mm EXTRAGTIUN (v03 ION)
E 50-
7% TM
5 _
3% 001mm
““
mumn WITH KERUSENE
_
US. Patent
April 4, 1978
Sheet 11 of 11
501
PISA
Mn“, Fe“ RELATION BETWEEN EXTRAGTIUN
40-
°
°
Mn
x
x
Fe”
f?
H
AND PH
4,082,832
1
53% HRGANIG PHASE
L|X—63 10%
5
LA—1 10%
‘520- 0011101 3%
E DILUTED wnu
““
KERUSENE
10-
j
2
:51
4
PH
Ml-
F E G92
Fe“ SGRUB EQUILIBRIUM
25"’:
2.0
1.0
13
‘lug/1111501
0
PH
2.5
1
4,082,832
2
cess of the acid as follows. FeS04.nH2O which is a
TREATMENT OF RAW MATERIALS
CONTAINING TITANIUM
BACKGROUND OF THE INVENTION
This invention is concerned with the production of
titanium dioxide which is characterized by recovery of
reusable H2804, high pure Fe oxide and hydroxide and
fractional recovery of Mn, V and Cr, etc., from Fe 10
SO4.nH2O and waste acid of 20 — 40% H2804 containing
abundant heavy metallic ions, which are by-products of
the production of TiO; by dissolution of Ti raw materi
als, such as, ilmenite, steel production slag, such as,
electric furnace slag, convertor slag with H2804.
In the conventional production of TiO; using H2804,
the required amount of 98% H2804 per 1 ton of TiO;
by-product in the pretreatment process is dissolved
with water or acids from the fourth stage, the oxidation
of Fe2+ ions in the resulting aqueous solution to Fe3+
ions is finished and then Fe3+ ions in the resulting aque
ous solution are extracted into the organic phase by
contact of the organic solvent (C). The resulting in
crease in the concentration of regenerated acid by sev
eral repetitions of the above operation as necessary
produces reduction in the energy required in the follow
ing concentration processes of the acid.
The fourth characteristic of the present invention is
concerned with the treatment of FeSO4.nH20 with the
fractional extraction of Mn and Fe ions as follows. After
dissolution of the FeSO4.nH2O by-product with water,
Mn“ ions in the resulting aqueous solution are ex
tracted with an organic solvent (F) into the organic
product is 3.5 to 4.2 tons. Nevertheless, an economical
phase to separate them from the Fe2+ ions in the result
treatment of FeSO4.nH2O and waste acids produced in
ing aqueous solution, the Fe2+ ions are oxidized to
abundance as by-products after the separation of Ti 20 Fe3+ ions and then the Fe3+ ions are extracted into the
compounds by the hydrolysis process has not been
found and the practice of retaining or discarding them
in the untreated form has given rise to serious pollution
organic phase by contacting them with the organic
solvent (C). The concentration of the recovered acid is
enhanced by several repetitions of the above operation
problems. This invention has been developed to over
as necessary and by recycling for dissolution of the raw
come the faults of the conventional production process 25 materials by way of the concentration process.
described above.
The ?fth characteristic of this invention is concerned
with
the reduction of the recovery cost by increasing
SUMMARY OF THE INVENTION
the Fe concentration in the aqueous solution which is
The present invention relates to the production of
introduced into the recovery process of HCl and Fe as
titanium dioxide which is characterized by the recovery 30 follows. The Fe concentration of the aqueous solution
of reusable H2804, high pure Fe oxide and hydroxide
introduced into the recovery process of HCl and Fe is
and fractional recovery of Mn, V and Cr, etc., from ' increased by extracting Fe3+ ions in the back-extraction
FeSO4.nH2O and waste acid of 20 - 40% H2804 con
solution of the organic solvent (C) with contact of the
taining abundant heavy metallic ions, which are by-pro
organic solvent (B) and stripping with water. The in
ducts in the production of TiO; by dissolution of Ti raw 35 creased Fe concentration produces the reduction of
materials, such as, ilmenite, steel production slag, such
recovery cost.
as electric furnace slag, convertor slag, with H2804.
The 6th characteristic of this invention is concerned
The summary of this invention is as follows. The
with the reasonable recovery of Fe compounds using
present invention is firstly characterized by the absence
both solvent extraction and diaphragm-electrolysis
of the production of waste acids and FeSO4.nH2O is as 40 techniques as follows. The back-extraction solution of
follows: The aqueous solution pretreated after dissolu
the organic solvent (C) or of the organic solvent (B) is
tion of the Ti raw materials with H2504 is brought into
introduced into the cathode compartment of the dia
contact and mixed with an organic solvent (A) to ex
phragm-electrolysis, Fe3+ ions are reduced to Fe“ ions
tract metallic ions, such as, Cr3+ and Nb5+ ions in the
there, free acid is transferred to the anode compartment
?rst stage and the bulk of Ti ions in the resulting aque 45 and hydrated Fe oxide or hydroxide is recovered by the
ous solution is separated by well-known hydrolysis
contact of air or oxygen with the aqueous solution in
process in the 2nd stage. The metallic ions, such as, Ti,
the cathode compartment containing a lesser amount of
Mn and V ions remaining in the resulting aqueous solu
free recovered acid.
tion are extracted into an organic solvent (B) in the 3rd
The 7th characteristic of this invention is concerned
stage, an organic solvent (C) extracts Fe ions in the
with the fractional recovery of metallic ions coex
resulting aqueous solution after the oxidation of Fe2+
tracted into the organic solvent (B) as follows. Mn, V
ions to Fe3+ ions in the 4th stage and V5+ ions in the
and Fe ions coextracted into the organic solvent (B) are
resulting aqueous solution are extracted into an organic
scrubbed with HCl or H2504, Ti ions in the organic
solvent (D) in the 5th stage. The resulting aqueous
solvent (B) is back-extracted into the aqueous solution
solution from the 5th stage is the reusable regenerated
acid for use in dissolution of raw materials.
The second characteristic of the present invention is
concerned with the extraction of Fe ions from the aque
ous solution using C]; gas for the oxidation as follows:
After the conversion of Fe2+ ions in the aqueous solu
tion from the 3rd stage as described hereinafter to Fe“
ions using C12 gas, the amount of HCl required to ex
tract Fe3+ ions in the aqueous solution as the Fe chlo
ride complex is added to the resulting aqueous solution
and is contacted with an organic solvent (B) to extract 65
Fe-Cl ions into the organic phase.
The third characteristic of this invention is concerned
with the reduction of energy in the concentration pro
with contact of (NH4)2CO3 + NH; solution, and then
the organic solvent converted from H type to NH; type
in the above operation is again converted to H type
with contact of H2804. When Cr’+ ions are coex
tracted, those in the organic phase can be recovered
into the aqueous solution with contact of BC] + H202
or HCl + NaCl solution. Thus, the individual metallic
ion coextracted into the organic solvent (B) are frac
tionally recovered. When Al“ and Mg2+ ions are accu
mulated in the recovered acid during recycle of the
recovered acid, the enhancement of their ions concen
tration is depressed by taking one part of out the extrac
tion system and the solution is taken out is recovered as
(NH4)2SO4 by neutralizing with NH3.
4,082,832
3
Since the desired purpose can be accomplished by
installation of the process based on this invention along
with the conventional production process of TiO2, the
control of production line of TiO; and its quality are
unchangeable and consequently the practical applica- 5
Tioz
FeO
Fe2O3
v20,
MnO
cr,o3
MgO
54.20
53.13
26.60
19.11
14.20
22.95
0.16
0.19
0.40
0.94
0.07
0.03
1.03
0.92
Values in wt.%
tion of this invention is very easy and the economical
recovery of valuable metals which could not be eco
2 to 2.5 tons of raw material described above per 1
ton of TiO2 product is sulfatized with 3.5 to 4 tons of
fore, the present invention has a great deal of industrial
98% H2804. After heating to sulfatize, Fe3+ ions in the
values for the connected industrial ?elds.
l0 resulting aqueous solution is completely reduced with
Fe scrap. The clari?ed solution is produced by remov
DETAILED EXPLANATION OF THE
ing undissolved residues. The chemical composition of
INVENTION
the aqueous solution which is obtained after removing
The present invention will be explained in detail with
one part of Fe ions as FeSO4.nH2O crystal is shown as
reference to drawings.
15
follows
FIG. 1 and FIG. 2 show a general flow-sheet of the
nomically recovered hitherto becomes possible. There
present invention.
FIG. 3 is a graph showing Nb extraction equilibrium
curve with amine in the ?rst stage.
T 200
32
300
0.1
1.8
0.3
1.6
Valuesing/l
FIG. 4 is a graph showing Cr3+ ion extraction equilib 20
rium curve with amine in the ?rst stage.
FIG. 5 is a graph showing Cr3+ ion back-extraction
The synthesized solution having the above mentioned
equilibrium curve with I-ICl or H2804 in the ?rst stage.
chemical composition and no Fe3+ ions was as a stan
FIG. 6 is a graph showing Cr3+ ion extraction equilib
dard solution in the following experiment.
rium curve from sulfate solution in the third stage.
25
_ (1) The First Stage
FIG. 7 is a graph showing Ti“ ion extraction equilib
rium curve in the third stage.
The extraction of Cr3+ and Nb“+ ions with the or
FIG. 8 is a graph showing Ti4+ ion back-extraction
ganic solvent (A) is run before hydrolysis process
equilibrium curve in the third stage.
owing to their superior extractability in lower concen
FIG. 9 is a graph showing Cr3+ ion back-extraction 30 trations of free acid and higher temperatures of the
equilibrium curve in the third stage.
aqueous solution. Organic solvent (A) is made up of
FIG. 10 is a graphshowing Fe3+ ion extraction equi
primary, amine secondary, tertiary or quaternary
librium curve with DZEHPA in the fourth stage.
amines, for example, “Primene JMT” (tradename, pri
FIG. 11 is a graph showing HFeCl4 extraction equi
mary amine produced by Rohm and Haas), “Amberlite
librium curve with TBP in the fourth stage.
35
FIG. 12 is a graph showing FeClf extraction equilib
rium curve with amine in the fourth stage.
LA-l” (tradename, secondary amine produced by
Rohm and Haas), “Alamine 336” (tradename, tertiary
amine produced by General Mills), and “Aliquat 336”
(tradename, quaternary amine produced by General
FIG. 13 is a graph showing Fe3+ ion back-extraction
equilibrium curve in the fourth stage.
Mills), 2 - 5% higher alcohols such as, octanol, dodeca
FIG.‘ 14 is a graph showing HFeCl4 and FeCl; back 40 nol or isodecanol as a modi?er and aromatic aliphatic or
extraction equilibrium curve in the fourth stage.
paraffin hydrocarbon as a diluent. The organic solvents
FIG. 15 is a graph showing V5+ ion extraction equi
used in this experiment indicate only one example and
librium curve in the ?fth stage.
of course similar organic solvents can be utilized.
FIG. 16 is a graph showing the relation between V“
- Extraction ion extraction and pH.
45
The extraction test is done with the increased concen
FIG. 17 is a graph showing V5+ ion back-extraction
tration of Cr3+ and Nb“ ions by adding and adjusting
equilibrium curve in the ?fth stage.
the CrZ(SO4)3 and NbCls concentration in the aqueous
FIG. 18 is a graph showing the relation between
solution described above. Cr“ and Nb“ ions are ex
H2804 concentration and Fe3+ ion extraction coef?ci
tracted according to the following formulas.
(My):
NbO(SO
-
H RN
+
11+
=1
1&6! ) + ($2) :2
CrSO4
(Aq)
(6:8)
(Aq)
(1121mm) . Nbo(so.,),-
(see FIG. 3)
(H RNHS?)g CrSO _
(see FIG 4)
’
(oré)
‘
'
The extractability of Cr3+ ions by amines follows the
order: primary amine > secondary amine > tertiary
amine. However, there is little difference in the extract
ability of Nb“ ions with various amines. The main
ent.
FIG. 19 is a graph showing the relation between
Mn2+ and Fe2+ ions extraction coefficient and pH.
FIG. 20 is a graph showing Fe2+ ion scrub equili rium curve.
'
The following explanation is based on the experi 65
ments carried out by the inventors. The typical chemi
factors of the Cr3+ ions extraction are temperature,
contact time and concentration of free acid. The high
extractability of Cr3+ ions is obtained the 50° to 80° C
and the longer contact time the higher the concentra
tion of free acid.
- Stripping -
Cr3+ ions extracted into the organic solvent (A) are
cal analysis of ilmenite used commonly as a raw mate
stripped from the organic phase with by contact with
rial of TiO; is shown as follows.
HCl or H2804 according to the under formula.
4,082,832
5
(H'ZRNIF) . CrSOf
+
(Org)
15% RC]
20% HCL
l H2804 :2 HZRN
(Aq)
+
(Org)
Temp.
20’ C
Back-extraction test (see FIG. 5)
Back-extraction %
Temp.
88.9% 20% H2804
20° C
20° C
99.0% 30% H2804
l Cr2(SO4)3
+
(M)
6
2 H+
(M)
Back-extraction %
81.4%
60° C
98.0%
After removing Cr3+ ions from the organic solvent 10
(A), Nb5+ ions is stripped from the organic phase with
_
contact of NH4F + NH3 solution according to the fol-
Flow
lowing formula.
ratio
RNH+
.
(HiOrE) )
NbOSO
( ‘)2
_
+
NHF
(A3)
+
4NHOH :2
HRN
(A11)
(6m)
(2) The Second Stage
. .
+
NbO
A
a-
.
.
.
5 Sta e
A large amount of T1 ions is removed as T1 hydroxide 2O mixes
by hydrolysis process of the resulting aqueous solution
from which Cr3+ and Nb5+ ions have been extracted.
The approximate
chemical
composition of the liquor
after separation of t1tamum 1s shown as follows.
Inlet(Aq)
+
0gp?’
raiiis
,
3mm
2(NH
Out1et(Aq)
SO
+
(X315 ‘
NHF
(A3)
O/A
Ti
V
Fe
HSO
Ti
V
Fe
H50
1.0/
7.1
0.2
31.8
300
tr
0.18
31.8
300
z
4
2
4
settler m
T
V O“t:t(0‘g)S
e
H 0
7.1i 0.02
25
“WEBBPA
20%
<0‘01 <1“ 4
3% octane] diluted
with kerosene
'rio, Fe“
7
T.I-1,so,
or“
V“
Mo2+
Mg2+
300
Tr
0.3
2.8
Values in g/l
1.6
32
“Ming/1
.
- Scrubbing -
30
(3) The Third Stage
V“, Fe“ and Mn2+ ions, which are extracted in the
low concentration of free acid, coextracted with Ti“+
ions into the organic solvent (B) are scrubbed from the
organic solvent (B) by contact with of HCl, H2804 or
Ti ions and one part of the V4+ ions in the resulting
HNOQ, but Ti4+ and Cr“ ions are not scrubbed.
aqueous solution are extracted into the organic phase
with the organic solvent (B). When there are Cr3+ ions 35
from the omission of the ?rst stage, Cr3+ ions are coex-
tracted with Ti ions into the organic solvent (B) as
'
'
'
shown in FIG. 6. The orgamc solvent (B) is composed
Scrubbing test with 15% KC]
Metalli; igns
concen
a
Flgw
on
I810
in the on; phase
o/A
hm“
3
Temp.
of alkyl phosphoric acid, for example, D2EHPA(D1-22+
.
.
Mn
ethyl hexyl phosphor-1c ac1d) and HZDDP (Mono-dode- 40 v4:
0,5 g/l
cyl phosphoric acid), 2 - 5% higher alcohols, such as,
18°31
(1)45) g)
I:
601C v
octanol, decanol or isodecanol as a modi?er and aro-
Fri-4+
7:0 M
II
Roomtemp_
0.2 g/l
1.0
Room temp.
1,0
"
B k
BC '
“meg extraction %
.
15 mm.
"
30
99.5%
99.0%
9%;%
0%‘;
matlc, aliphatic or paraf?n hydrocarbons as a d1luent.
-
Extraction
-
.
.
.
Ti4+ ions are extracted with the organic solvent (B) 45
The organic Solvent (B) extracted T1 Ions are scrub"
according to the under formula
bed by contact of HCl, H2804 or HNO; to remove V4+
Ti4+ +
(Aq)
4[(Ro),PooH]
(01's)
==
Ti[(RO)2P00]4
(org)
+ 411+
(Aq)
(see 1110.7)
and Mn“ ions, etc. coextracted with Ti4+ ions into the
organic solvent (B). The selection of HCl, H2804 or
_
_
_
The fesultmg Solutlon Includes a Small amount of
HNO; as a scrub solution is done after consideration of
the ?nished recovery form of scrubbed V and Mn, etc.
V5+ ions and they are slightly extracted. While, Fe3+ 55 The organic solvent (B) after the scrubbing process
ions are not commonly contained in the resulting soluincludes only Ti4+ ions, but includes also Cr3+ ions
tion, but if Fe3+ ions exist in it, they are completely
provided that the ?rst stage is omitted_
extracted like Ti4+ ions. Mn2+ ions are extracted as the
_ Continuous scrubbing test -
°°n°ent1'?ti°n °f free aFid lowers-
The apparatus for the test is the same one used for the
' con‘tmuous extractl?“ test '
6° extraction process and the ?ow rates of organic aqueous
The hquor as shown m the following table was Conphases are 0.5 l/min. and 0.05 l/min., respectively.
tinuously treated with the organic solvent (B) at a ?ow
rate of 0.15 l/min. using a mixer-settler (100 mm W X
500 mm L X 180 mm H). The mixer was of the pump-
MEMBE
suction type and rotated at 120 - 310 rpm. depending 65 APW
12%‘: 'Inlet gorg)
on the interface level in the settler using a non-stepwise
speed changer. The organic solvent used consists of
20% DZEHPA, 3% octanol and kerosene in balance.
o/A
mus
5 Stage
inim-
10/1
Ti
v
7.10 0.02
0625‘
Ti
v
ougA‘1;’
T; v Note
_
Temp‘: 35. C
1.10 0.01 - 0.2 Scrub sol.
4,082,832
7
8
by contact with of H2804 + H202, HCl + H202 or HCl
Flow
22?:
The mgiznzlilzgmbbm
+ NaCl solution and then the NH, type of the organic
wsbmlet
solvent (B) is converted to the H type. (see FIG. 9).
22:
t 01v
Tior v %iiq%_Note
settler
5
(4) The Fourth Stage
= 15% BC]
- Extraction -
value, in 8/1
Fe2+ ions in the resulting solution in which Ti ions are
separated are converted to Fe3+ ions with H202, oxy
- Stripping -
gen, high pressure air or electro-oxidation and Fe“ ions
Ti4+ ions in the organic solvent (B) after the scrub. 10 in the resulting aqueous solution are extracted into the
bing process are stripped in the following stripping
orgamc Phase Wlth the Orgamc $°1Vent(C)-The ofgamc
process,
solvent (C) is composed of alkyl phosphoric acid, for
Back-extraction test of Ti ions with various backextraction solutions
example, DZEHPA, mixed solvent of alkyl Phosphorlc
acid and LIX-63 (tradename, chelate reagent produced
Flow ratio ; Q/A = 1/1, shaking time; 15 min 15 by General Mills) or a-bromo lauric acid, 2 — 5% higher
Tel-111).; Room temp,
alcohol as a modi?er and aromatic, aliphatic or paraffin
hydrocarbon as a diluent.
The extraction mechanism of Fe“ ion with alkyl
Back-
Back-ex-
extraction %
a2N“13506
S 4
a
o
0
°-5N
ennso4 +I%HO
22-3;-
12,, H0,
4N
HNO;
8N HNO
00.4
(NI-192224
+ NI-(iio
Satin‘ t
(NH
38.0.5
llN H3113)4
5.7
1M (gmpzcofi N 3
99.5
6N Hci
'
'
‘
traction % 20 phosphoric acid is shown as follows. (See FIG. 10)
12 O4‘
Fe3+
36.04
1 2
0
+
(Aq)
3 [(RO) 2 room
(org)
.
25
.
—
_
.
Fe [(RO) 2 P00] 3
+
a rr+
(org)
.
.
(Aq)
.
While, Fe2+ ions are oxidized to Fe“ ions using C12
gas and Fe ions are extracted into the organic phase
with the organic solvent (B) after adding HCl to the
It is considered from the result of the back-extraction
resulting aqueous solution in an amount enough to ex
tract the Fe“ ions as an Fe chloride complex. The
test that 0.5 M - saturated (NH4)2CO3 + NH; solutions
with pH values maintained between 7 and 9.5 and over
2 M(NH4)2SO4 + NH3 solutions with pH values main- 3° organic solvent (B) is made up of phosphoric acid ester,
for example, TBP (tri-butyl phosphoric acid), TOP
tained over 7.0 are the most suitable back-extraction
(tri-octyl phosphoric acid), DBBP (di-butyl butyl phos
solutions of Ti ions from the standpoint of cost and
phonate) or TOPO (tri-octyl phosphine oxide) and aro
subsequent operations. Therefore, the mechanism of the
matic, aliphatic or paraffin hydrocarbons as a diluent.
back-extraction of Ti ions is shown as follows.
Ti [010M100],
+
201119200,
(Aq)
(01's)
4 [(RO),_P0ONH4]
+
+
4NH4OH
2 (NH,),C0,
(01's)
2:2
Ti(OH)4+
(Aq)
(DP!)
(see FIG. 8)
(Aq)
.
As shown in the above formula, (NH,,)2CO3 used for
Moreover, the organic solvent (B) may be made up of
girazifgneztg?it1::dfglrgg {K5313 foigledmrizets bacifh
higher alcohol as a modi?er and aromatic, aliphatic, or
_
.
__ .
.
_
NR3 to form (NHOZCO again
primary,
secondary,
tertiary
or
quaternary
amine,
45 paraffin hydrocarbons as a diluent. The test used Pri
mene-JMT as a primary amine, LA-l as a secondary
amine, Alamine 336 as a tertiary amine and Aliquat 336
Flow
Appmms
3*)‘:
The third stage - Stripping
Inlet Outlet Outlet
(915,8 (qfig) (‘35? Note
5 Stage_
mixer-
as a quaternary amine. Of course, similar amines can be
utilized besides the amines described above. Further
0 more, mixed solvent ‘of phosphoric acid ester, such as,
IWNH01cc:
1/1
7.10
“"1"
0,01
7.10'
TBP and tertiary amine such as TOA (tn-octyl amine)
+ NH
can be used. Fe ions are extracted into the organic phase
PH‘ 9-5;
Temp“ 23° C
with phosphoric acid ester or amine according to the
following formulas.
FeCl;
+ H'‘' +
C1’
+
ZTBP
2i HFeCl4.2TBP
,
(M)
(M)
(M)
(org)
FeCl; + (R3NH)+ a: (R,NH)+.Fec1,—
(M)
(ore)
(Org)
(Extraction by TBP
seeFIG. 12)
(Org)
(Extraction
by tertiary
amine. see FIG. 12)
Remark : The value of Ti‘ in the back-extraction solution is one obtained the
remelting the precipitate as Ti(Ol-I)‘.
- Stripping -
As the organic solvent (B) becomes the NH, type by 65 Fe3+ ions extracted into the organic phase with the
stripping Ti ions, it is converted to the H type by with
organic solvent (C) are stripped from the organic phase
contact of H280, or HCl in the following process.
with HCl and the organic solvent (C) is regenerated as
When Cr3+ ions are coextracted, Cr3+ ions are stripped
shown in the following formula.
4,082,832
9
F (R0 P00
+
cl (0)38) 13
3HCl
C1
(Aq) a Fnew’
+
3
0) P00
[(R(d1'8)
H]
10
(see 1716.13)
While, Fe chloride complex extracted into the or
amine, Alamine 381 (tri isooctylamine produced by
ganic phase with the organic solvent (B) is stripped
Ashland Chemical Co.) as a tertiary amine and Aliquat
from the organic phase with water and the organic
solvent (E) is regenerated according to the following
formulas (see FIG. 14).
amines can be commonly utilized besides the amines
mentioned above.
336 as a quaternary amine. Of course, various similar
- Stripping -
I-lFeCl,,.2TBP
+ 1120 =2
(Org),
(M)
Feel,
(M)
+
HCl +
VO(SO4)2~ ions extracted into the organic solvent
(D) are stripped from the organic phase with the
contact of (NH4)2SO4. While, VO3- ions extracted into
the organic solvent (D) can be stripped with NH4Cl +
NH; (see FIG. 17). Both types of V ions are recovered
TBP
(Aq)
(Org)
- Continuous extraction and stripping test -
as the form of NH4VO3.
The apparatus used for the test is the same one used in
(6) The Treatment of By-product FeS04.nH2O
the ?rst stage. The ?ow rate of organic and aqueous
phases were 0.1 l/min.
The H2804 concentration produced after the extrac
Extraction
Appara-
Flow ratio
Inlet(Aq)
Outlet(Aq)
Outlet(Org)
tus
10 Stage
O/A
Fe
H2804
Fe
H1804
Fe
H2504 Note
30% DZEHPA
mixersettler
3/1
31.8
300
<0.0l
300
10.6
<0.01 3% decanol
kerosene
mixer-
4/1
31.8
300
<0.01
300
7.94
<0.01 15% TBP
15 Stage
settler
I
kerosene
values in g/l
Stri
Appara-
Flow ratio
tus
O/A
10 Stage
.
Inlet(0rg)
in
Outlet(0rg)
Outlet(Aq)
Fe
HCl
Fe
I-lCl
Fe
l-ICl
Note
10.6
—
0.1
—
15.9
150
Room tem .
20.5
0.6
1.5
73.4
189
150 5/1
60°
mixer
settler
"
1.5/1.0
10/1
7.94
H l
Values in g/l
(5) The Fifth Stage
40
- Extraction -
The resulting aqueous solution extracted off Fe3+
tion of Fe3+ ions and almost all heavy metallic ions in
ions contains a small amount of Al“, Mg“, Mn2+ and
the fourth stage is 250 - 300 g/l and consequently this
V“+ ions and is reused for dissolution of Ti raw materi
low concentration of H2504 enhances the energy cost of
als through the concentration process. However, since 45 the concentration to reuse for the dissolution of raw
these metallic ions are gradually accumulated in the
materials, through the concentration process. The
recycling process, it is necessary to take them out the
H2804 concentration is increased by dissolving Fe
system and to prevent their accumulation. When acid is
SO4.nH2O by-produced in the pretreatment process into
taken out the system or is recycled to reuse, it is con
the aqueous solution from which the Fe3+ ions are re
nected with the improved economization of the appara 50 moved in order to reduce this energy cost. The several
tus to extract and recover the V“ ions which have an
repetitions of the above operation in accordance with
economical value among them.
the demand can diminish the energy cost of concentra
In the case of recycling for reuse, VO(SO4)2— ions in
tion. The relation between the H2504 concentration and
the resulting aqueous solution which has no Fe ions and
the Fei+ ions extraction coef?cient is shown in FIG. 18.
300 — 500 g/l of free acid are extracted into the organic 55
FeSO4.nH2O often includes MnSO4. As shown in the
phase by contact of the organic solvent (D). (see FIG.
?ow-sheet of FIG. 2, Mn“ ions are separated from
15). In the other case of taking acid out the system,
Fe2+ ions by extracting Mn“ ions by contact of the
V03- ions in the aqueous solution, whose pH values are
organic solvent (F) in the lower concentration of free
maintained between 2 and 4 with NH3, are extracted
acid produced by the dissolution .of the FeSO4.nH2O
into the organic phase with contact of the organic sol
crystals with water (see FIG. 19).
vent (D). FIG. 16 shows the relation between the pH
The organic solvent (F) is composed of alkyl phos
and V extraction coef?cient.
phoric acid, for example, DZEHPA, HZDDP, 2 — 5%
The organic solvent (D) is made up of primary, sec
higher alcohol as a modi?er and aromatic, aliphatic or
ondary, tertiary or quaternary amine, 2 - 5% higher
paraf?n hydrocarbons as a diluent. While, the organic
alcohols such as, octanol, decanol or isodecanol as a 65 solvent (F) may be made up of mixed solvent of
modi?er and aromatic, aliphatic or paraf?n hydrocar
DZEHPA and LIX-63 or primary, secondary, tertiary
bons as a diluent. The amines used for the test are Pri
or quaternary amine. As described above, the mixed
mene-JMT as a primary amine, LA-l as a secondary
solvents consisted of mainly alkyl phosphoric acid and 5
4,082,832
ll
- 20% of LIX-63, aliphatic hydroxy oxime or a-bromo
lauric acid are used to extract Mn ions.
A small amount of Fe2+ ions coextracted with Mn2+
ions are scrubbed from the organic solvent (F) with
contact of MnS04 solution having 2 — 3.5 of pH values,
the organic solvent (F) contains only Mn ions and con
sequently Mn“ ions are stripped from the organic sol
vent (F) with 300 g of H2804 in the following process.
- Continuous extraction test -
recovery and consequently the back-extraction'solution
is introduced into the cathode compartment of dia
phragm-electrolysis, and free HCl produced there by
the reduction of FeCl3 to FeCl2 is transferred to the
anode compartment and recovered.
'
The continuous extraction test using the under 10
- Continuous electrolysis test -
tabulated FeSO4.nH2O by~produced by the H2804 pro
The back-extraction solution of the organic solvent
(C) is fed into the cathode compartment by a quantita
cess was done and MnSO4 was added to the resulting
solution in order to facilitate the con?rmation of the Mn
extraction.
Tio2
0.22%
tive pump and the aqueous solution of low HCl concen
tration, which is the back-extraction solution of the
15 organic solvent (C) and contains no Fe ions, is fed into
the anode compartment‘
Chemical analysis of FeSOQ. nHzO
FeO
24.96%
12
ions is impossible to be increased as shown in FIG. 13,
the introduction of the above back-extraction solution
into the apparatus of the recovery by the thermal
decomposition process enhances the energy cost of the
M110
0.06%
Electrolysis condition
Material of diaphragm :
_
_
_
The pH value 1n dlssolvmg 250 g of the above crystal
with 1 liter of water was 1:8 and the ‘chemical composinon of the resulting solution to which Mn was added
Eldiaphragm
Anode = carbon
Mn
2.0
(5,53%
0:4§m1/cmz H
01 a
ectric resistance :
Fe
48.8
0.103 mm
Void gamut déaphlrlasm =
$2,; $3,533 Z'agm '
was sh°wn as follows"
Total H S0
90.7’ "
Film of Tetra-?uo ethylene
20 Thickness of diaphragm =
.
Cathode:
Ti
0.3
(Values in g/l)
2
-cm
Ti (Pt plating)
Extraction
Flow ratio
lnlet(Aq)
0utlet(Aq)
Outlet(0rg)
Apparatus
10 Stage
O/A
4/1
Fe
48.8
Mn
2.0
Ti
0.3
Fe
48.4
Mn
0.1
Ti
Tr
Fe
0.1
Mn
0.49
Ti
0.1
mixersettler
"
2/1
48.8
2.0
0.3
48.6
0.1
Tr
Tr
1.0
0.15
Note
20%
DZEHPA
10% LIX
63+l0%
D2EHPA
Values in g/l
Fe2+ ions are coextracted with Mn2+ ions from pH
values between 3.5 and 3.8. In this case, Fe2+ ions ex
51
Volume of anode or cathode room :
Temperature : 24 - 55° C
Current density 1 2 A/dm2
tracted into the organic phase are scrubbed from the 40
organic solvent (F) with MnSO4 solution having a pH
- Continuous test at steady state -
value of 2 — 2.5 and the concentraton of Mn in the
Cathode room
MnSO4 solution depends on the concentration of the
organic solvent (F). (see FIG. 20)
1163+
Inlet
130
(g/l)
outlet
0,4
Anode room
Inlet
0
Outlet
_
Stripping
Flow ratio
Inlet(0rg)
Outlet(0rg)
(Outlet(Aq)
Apparatus
O/A
Fe
Mn
Ti
Fe
Mn
Ti
Fe
Mn
Ti
5 ‘Stage
l0/ 1
0.1
0.49
0.1
-
0.06
0.6
—-
4.8
-—
mlxer"
300
H2 04
settler
10/1
Tr
1.0
0.15
—
0.01
0.15
—
9.9
—
Values in g/l
(all)
—
21-0
0
-—
the organic solvent (F) is recycled. Since the Ti concen- 55 22:10,
Ti ions in the organic solvent (F) are not stripped and
(gm
176
27'4
50
“8'0
tration gradually increases, one part of the organic solvent (F) is taken out the system and Ti ions in it are
(VB)
5.0
4.3
5.0
5.1
stripped from the organic phase with contact of the
(NH4)2CO3 + NH4OH solution.
Fe“
volume
The following diaphragms besides the one described
above were used.
(7) The Recovery of HCl by Diaphragm —- Electrolysis
As the concentration of Fe“ ions in the back-extrac
tion solution of the organic solvent (C) including Fe“
Material
Electric resistance
Acetic cellose
Polypropylene
0.05 - also-om2
0.12 - 0.27n-en1z
l.7 — 3.2 \ll-cmz
Ion exchange
Hole dia.
Void %
0.1 - 0.4“
58 - 62%
0.2 - 0.4"
38 _ 45%
Water content : 38%
Water permeab.
0.11-0.3 ml/cmz
0.02-o.2 nil/cmZ
4,082,832
13
14
-continued
Material
Electric resistance
Hole dia.
Void %
Water permeab.
membrane
The back-extraction solution of the organic solvent
(B) is the concentrated solution containing 75 - 85 g/l
of Fe and 200 - 240 g/l of HCl as described above.
are dissolved in sulfuric acid to form an aqueous solu
However, it is considered that the energy cost of free
tion of sulfuric acid containing dissolved titanium and
other metals selected from the group consisting of iron,
V, Mn, Cr, and Nb, and then forming a precipitate of
FeSO4. nH2O and the titanium in the solution is isolated
and subsequently recovered as titanium dioxide from
the aqueous solution, the improvement which com
HCl recovery by reduction of Fe2+ ions in the electroly
sis process becomes lower than that by thermal-decom
position process because free HCl exists in the back
extraction solution of the organic solvent (B). As for the
ion exchange membrane, any ion exchange membrane
prises:
may be used.
l. extracting Cr3+ and N‘b5+ ions from the aqueous
The solution containing Fe2+ ions, which consists of 15
solution by contacting the aqueous solution with a
the solution of Fe2+ ions produced by electro-reduction
?rst organic solvent selected from the group con
of Fe3+ ions (FeCl3 —> FeClz + Cl) and the solution
sisting of primary, secondary, tertiary and quater
which is recovered by transferring the solution, con
nary amines;
taining abundant HCl unused in the back-extraction,
2. separating the aqueous solution resulting from step
into the anode compartment are converted to FeCl; by
(1) and separating a major portion of the titanium
the oxidation with air or oxygen and one part of the Fe
ion in the solution by hydrolysis;
ions is precipitated and separated as hydrated Fe oxide
3. separating the aqueous solution resulting from the
or hydroxide according to the following formula.
hydrolysis treatment of step (2) and extracting the
25
2 FeClz + O + H2O = FeCl; + HCl + FeO(OH)
titanium ions remaining in the aqueous solution
Both HCl and FeCl; produced in the above formula
with a second organic solvent selected from the
are introduced again into the cathode compartment of
group consisting of alkyl phosphoric acids mixed
the electrolysis process and HCl and Cl_ which are
transferred to the anode compartment are recovered by
reduction of Fe3+ ions to Fe2+ ions. When there is the 30
apparatus of thermal-decomposition, FezO3 and HCl
with from 2 to 5 percent higher alcohols and aro
matic, aliphatic or paraf?nic hydrocarbons as a
diluent;
'
. separating the aqueous solution resulting from the
can be obtained by thermal-decomposition of the con
extraction of step (3), oxidizing the Fe+2 ions
centrated solution produced through several electroly
therein to Fe+3 ions and then extracting the Fe+3
sis processes from the viewpoint of water-balance.
Both Fe2O3 and FeO(OH) obtained as mentioned
above are high purity and can be utilized for ferrite and
group consisting of alkyl phosphoric acids in com
ions with a third organic solvent selected from the
bination with from 2 to 5 percent higher alcohols
pigment without further puri?cation.
and aromatic, aliphatic or paraff'mic hydrocarbons
The production of Ti02 based on this invention has
as a diluent;
the following advantages.
(1) The adoption of this production method has the
extreme advantages in the anti-pollution and economi
cal cost by working out the problem of FeSO4.nH2O ——
treatment which has been the most troublesome pro
cess.
(2) The recovery of valuable metals, such, as V, Nb 45
and Mn, etc., contained in a small amount is possible by
regenerating and reusing the waste acid economically,
40% H2504 after the hydrolysis process. The product of
the individual valuable metal is recovered in high pu 50
(3) The metals such as, Cr whose existence in the raw
materials is undesirable can be fractionally recovered
with solvent extraction techniques from the aqueous
solution before the hydrolysis process and consequently
the selection of the raw materials is very easy.
(4) The product-purity of the hydrated Fe oxide and
bons as a diluent; and then
6. recovering, regenerating and concentrating the
including a large amount of heavy metal ions in 20 -
rity.
5. separating the aqueous solution resulting from step
(4) and extracting the vanadium ions and other
remaining heavy metal ions with a fourth organic
solvent selected from the group consisting of pri
mary, secondary, tertiary or quaternary amines in
combination with from 2 to 5 percent higher alco
hols and aromatic, aliphatic or paraff'mic hydrocar
sulfuric acid remaining in the aqueous solution
resulting from step (5).
2. The process of claim 1 wherein the second organic
solvent after the extraction in step 3 is scrubbed with an
aqueous solution of H2804, HNO; or HCl whereby the
Mn, V and Fe ions contained therein are removed, and
then the thus treated second organic solvent is back
extracted with an aqueous solution containing
(NH4)2CO3, (NH4)SO4, NH4F or a combination of
NH4NO3 and NH; to transfer the Ti“ ions into the
aqueous solution and then separating the remaining
very high as used not only pig iron — raw materials, but
third solvent and then contacting said separated third
also for valuable ferrite or pigment and consequently 60 solvent with H2804 and extracting any Cr3+ ions in the
the economical value is enhanced.
thus treated solvent by washing with an aqueous solu
hydroxide by-produced in the acid recovery process is
(5) The whole system is built up as a closed-circuit
and the protection of the environment is possible be
cause the great part of the used reagent is recovered or
used as a product.
What is claimed is:
1. In a method for obtaining titanium dioxide from
titanium-containing raw materials wherein the materials
tion of HCl and H202 or HCl and NaCl.
3. The process of claim 2 therein the FeSO4, nHzO is
dissolved in the aqueous solution from step 3 prior to
65 the extraction with the third solvent.
4. The process of claim 3 wherein after dissolution of
the FeSOMHZO in aqueous solution from step 3, Mn2+
ions in the resulting solution are extracted with a sixth
15
4,082,832
nary amines;
solution from said extraction for the oxidation treat
ment.
16
sisting of primary, secondary, tertiary and quater
organic solvent leaving the Fe+2 ions in the aqueous
. separating the aqueous solution resulting from step
,
1. and separating a major portion of the titanium
5. The process of claim 4 wherein the Fe+3ions in the
ion in the solution by hydrolysis;
third solvent are extracted by contacting said third
solvent with said sixth solvent and then stripping said
. separating the aqueous solution resulting from the
hydrolysis treatment of step 2. and extracting the
titanium ions remaining in the aqueous solution
sixth solvent with water.
6. The process of claim 4 wherein a solvent selected
with a second organic solvent selected from the
from the group consisting of the third extracting sol
group consisting of alkyl phosphoric acids mixed
vent, the sixth extracting solvent and combinations
with from 2 to 5 percent higher alcohols and aro
thereof, said solvents containing said Fe3+ ions, is intro
matic, aliphatic or paraf?nic hydrocarbons as a
duced into the cathode compartment of a diaphragm
diluent;
electrolysis unit and subjected to electrolysis therein
. separating the aqueous solution resulting from the
whereby the Fe+3ions are reduced to Fe+2and free acid
is transferred to the anode compartment and hydrated
Fe oxide or hydroxide is recovered by contacting the
aqueous solution in the cathode compartment with air
extracting of step 3., oxidizing the Fe+2ions therein
to Fe+3 ions, adding HCl to the resulting solution
to form an iron chloride complex and then extract
ing the complex from the solution with a ?fth or
or oxygen.
7. In a method for obtaining titanium dioxide from 20
titanium-containing raw materials wherein the materials
are dissolved in sulfuric acid to form an aqueous solu
tion of sulfuric acid containing dissolved titanium and
other metals selected from the group consisting of iron,
V, Mn, Cr, and Nb, and then forming a precipitate of 25
FeSO4.nH2O and the titanium in the solution is isolated
and subsequently recovered as titanium dioxide from
the aqueous solution, the improvement which com
prises:
ganic solvent suitable for dissolving and extracting
said complex;
. separating the aqueous solution resulting from step
4. and extracting the vanadium and other remain
ing heavy metal ions with a fourth organic solvent
selected from the group consisting of primary,
secondary, tertiary, or quaternary amines, in com
bination with from 2 to 5 percent higher alcohols
and aromatic, aliphatic or paraf?nic hydrocarbons
as a diluent; and then
6. recovering, regenerating and concentrating the
l. extracting Cr3+ and Nb“ ions from the aqueous 30
solution by contacting the aqueous solution with a
?rst organic solvent selected from the group con
sulfuric acid remaining in the aqueous solution
resulting from step 5.
)1‘
35
45
50
55
65
‘it
t
i‘
ll!