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Патент USA US2120602

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i‘atented June 14, 1938 l
G THT
V
05
Kenneth
um Domain; Cleveland; Ohio
..-;
Application At to, 1985,
Serial No. 38,53d
11 4H." 1.4".
This invention relates to a process of making
oxides of a certain group of metals and has par
ticular reference to a process of preparing tita
nium oxide and/or zirconium oxide in substan
5
tially pure form.
_
'
In prior methods of treating titanium ores
such as rutile, ilmenite, etc. and other titanifer
ous material with varying proportions of associ
ated iron compounds, the titanium‘bearing ma
10 terial is subjected to ‘the action'oi strong sul
phuric acid whereby FeSO; is formed from the
iron, present in the compounds. This FeSOi pos
’
Y
(Cl. 23-16)
reduced to the metallic state but the titanium
compounds will not be thus reduced.
A further object‘ of this invention is to treat
the mass containing the metallic iron and the’
unreduced material with chlorine or certain" 5
other suitable
eous compounds that will form
FeCls with the metallic iron and controlling the
temperature so that the, titanium compounds
present in the mass will‘ not be converted into
'I‘iClt, the process however being ced out at 10
a su?lcient temperature to volatilize the FeC'ls‘
formed by the reaction. =
A further object of this invention is to recover
sesses practically no commercial value and, fur
thermore, it has been ‘found di?lcult to remove . T102 in a condition of high degree of purity and
15 the FeSO4 from the precipitated titanium com
pound to a sumcientextent so that it will not
discolor the ?nal product, which is T102.‘ -
In. another of these prior processes, a mixture
of titanium bearing material together with car
20 bon or other reducing agent is subjected to the
action of chlorine, whereby both. FeCla and TiClt
are formed, but it has been found dimcult a»
effect a clean separation between thesechlorldes,
and the production of T102 having the desirable
- 25 pigment‘ properties'is rather trying due to the
di?iculty of controlling the hydrolysis of 'I‘lClt
in aqueous solutions.
»
'
,
In another of. these prior processes, a heated
mixture of ilmenite, or other titanium bearing
substantially free from
oloration by the ma
terial remaining after the Fema has been evolved.
A still further object of this‘ invention is to pro
vide processes for ‘making T102 and Zl'Oz which
_ will avoid the disadvantages incident to the prior
pres.
_
_
_
Other, further and more speci?c objects of this
invention will become readily apparent to per
sons skilled in the art from a consideration of the
following description wherein certain speci?c em
loodiments of my invention are set forth.
when compounds, or solid solutions, of tita
nium oxide and iron oxide’ are heated in the
presence of carbon, or certain other reducing re
agents suchas coal, coke, oil, tar, hydrocarbons,
30 substance, ‘with carbon and chlorine is treated . etc, the iron omde will be reduced first and at a 30
under temperature .control so that‘the FeCls will I lower temperature than the titanium oxide. The
volatilize but the ,TiCh will not pass off. This reactions which may vary according tothe tem
process also possesses the di?iculties involved if
perature of the material being treated, are illus
T102 possessing the ‘desirable pigment properties
trated by the followingequations:
'
'
35 is to. be produced from the TiCh. Also. from a
commercial standpoint, production of TiO: vfrom
T1014, starting with'ilmenite or other. titanium
Reaction (-2) is reversible as to the Fe and C0:_
bearing materials, has been proved tobe unfea
sible, because it is commercially impracticable to and, if too much C02 is present, a'secondary re
-'
'
40 recover the chlorine as hydrochloric acid, in view action takes place as ~follows:
of the very dilute condition in which the hydro-v
ne+boa=reo+co
<3)
chloric acid is formed.
-
'
g
_
Among the obiects‘of this invention is to pro
‘
vide a process for the treatment of ores and,
45 other materials whereby selectivereduction of
some of the constituents of the treated mass is
effected while the reduction of the rest of the
mass is prevented, then forming a volatile halo
40
The percentage of 002 which may‘ be present var
ies with the temperature of the process. For el
i’ective operation, careshould be taken that the 45’
Fe‘is notreoxidized by the admission of excess
air after it is reduced.
-
In preparing T102, a titanitjerous material,
gen compound of the reduced mass while pre- . such as rutile, ilmenite, etc. is mixed in ?nely
5o venting the halogenation of the unreduced mass. ground condition with ?nely ground carbon in 50
substantially stoichiometric relation to the iron.
More speci?ca1ly,~it is an object of this inven
' tion to treat ilm'enite, rutile or other titanium
_ bearing‘ materials with carbon .or suitable com
pounds of carbon, at the» proper temperature
present in. the titanii’erous pmaterial, and the
mass is heated at a .temperature'suf?cientlyl high ‘
to reduce the'iron compounds to metallic iron.
55 whereby the iron present in the material will be ‘ A temperature or about 900° C. has been found 55
2,120,602
' 2
satisfactory. However, this temperature should
be kept below 1000” C. in order to prevent reduc
tion of the titanium compounds present in the
side reactions involving combination between
carbon and chlorine and causing loss of chlorine.
2. The reduction and chloridization are accom
mass. The reduction with carbon is conducted
Cl in a controlled atmosphere, with or without ad
plished in two steps, which admit of the forma
tion of FeCh without the simultaneous formation
mitting air, theadmission of air if desired being
of any large amount of TiCh. The bulk of the
titanium remains‘in the residue as T102.
regulated so as to maintain proper equilibrium
between Fe, FeO, C, CO and C02. The most suit
able equilibrium for accomplishing the desired
10 reduction .of FeO to Fe is believed to be when
there are four parts of CO present for each part
of CO2. After the iron compounds have been
reduced, any slight excess of carbon is removed
and the residue is subjected to a chloridizing
15 treatment at an elevated temperature above 350°
C. and below 1000" C., by passing chlorine gas,
or a‘gas containing chlorine such as hydrochloric
acid over or through this residue, whereby FeCla
is produced from the iron, and if the tempera
ture of the mass be sufliciently high the FeCh
will volatilize and may be condensed and re—
covered by suitable apparatus. The titanium
compounds ‘do not volatilize during this treat
‘ment, and after removal of FeClz, the residue
25 will contain a high percentage of TiO: and a
relatively small amount of iron and other im
purities and will be ofv such a character as to
serve well as the material to be used in the fol
3. By reducing and chloridizing in two steps,
it is feasible to effect separation of the iron and
titanium without close temperature control, be 10
cause the chloridization of the- iron can be ac
complished through a wider rangev of tempera
ture, when there is substantially no carbon pres- .
out, without an accompanying reaction of the
chloridizing agent upon titanium compounds to
form TiCl4. Temperature control in a process
of this kind presents many di?iculties in. com
mercial operation and by dispensing with the
need for-close temperature control a decided ad
20
vantage is derived.
4. By effecting reduction and chloridization in
two steps, and the chloridization step being car
ried on in the absence of carbon, it is possible
to conduct the chloridizing operation at a
higher temperature than when reduction and
chloridization are carried out in one step. I am
therefore able by my process to reduce the time '
of chloridizing and to produce a residue of tita
lowing steps for the commercial production of nium oxide fairly low in iron. Furthermore, the
'30 paint pigments. The amount of iron left with chloridizing agent is also more eiiiciently em 30
the titanium depends on how near to completion
ployed. I
the'reaction is carried,'but for the'subsequent
5. By removing a large part of the iron as
FeCla, it is commercially feasible to form the com
plex salt containing titanium and ?uorine in the
step of my process I prefer to remove the iron
down to 3 or 4% of the residue.
35
Y
c
The residue made as above described, contain
ing 3 to 4% iron, may be further puri?ed by mix
treatment with NH4F and/or HF.NH4F through
ing with NH4F and/or HFNH4F and heated for
If large amounts of iron are associated with the
titanium bearing material the 'di?iculty of sep
arating the iron from the titanium is' so great
an intermediate step in the formation of ‘H02. ‘
about an hour, to convert the T102 to one or
I -more water soluble complex salts containing
40 titanium and ?uorine, which may or may not be ' wh'en carried out by the prior processes that the 40
acidulated. The time of heating varies with the
?neness and thoroughness of the mixture. This
reaction should be, carried on at a temperature
latter step of forming the complex salt contain
ing titanium and ?uorine is of doubtful com
' below that at,which the complex salts volatilize.
45 I have found that a temperature ,of 300 to 350°
6. In' my process, a large part of the iron is re
C. is satisfactory to retain all of the titanium
. compounds in the solid
operation.
After
the
form at this point in the
treatment
with
NH4F
mercial value.
‘
covered as FeCl: which has considerable, com 45
mercial value. Also, the separation of the iron
from the titanium as volatile FeCl: eliminates
the costly washing steps heretofore employed in
and/or~ ‘ the removal of the iron.
50 HF.NH4F, the reaction product is placed in water
which dissolves the complex titanium salt.‘ Am
monium sulphide is then added to the aqueous
solution of the titanium salt to precipitate any
7. In my process, the formation of TiCh is pre
50
vented, thus overcoming the di?iculties ‘caused
by the presence of the T1014 which is not stable
in a water solution and does not respond readily
residual iron compounds which may have been ' to treatment for the recovery of T102 in a form
55 carried along in the process. The precipitated. suitable for a paint pigment. Also, by pre 55
FeS is then removed from the solution, by ?lter
ing or other suitable means, and the clear solu
tion of the titanium salt is treatedwith NH4OH
to precipitate the titanium as the hydroxide.
60 The titanium hydroxide is separated by ?ltration
or any other suitable manner and then calcined,
to obtain TiOz of good color, high tinting strength
and other valuable pigment properties.‘
The NI-I4F, produced in the above reaction be
65 tween the complex titanium salt and the NHiOH,
venting the formation of T1014 a large saving
in chlorine is effected. If TiCh is allowed to
form, the excessive consumption of chlorine in
cident thereto renders the process impracticable
commercially. In my process the chloridization 60
e?iciency is about 100%.
'
can be recovered and used over again.
.My process possesses the following distinct ad- ‘ N'H4F and/or HFNHJ‘.
vantages.
r‘.
.
.
1. By proportioning the carbon employed in
70 the reduction ofthe iron oxide so that it is in
substantially stoichiometric relation thereto, I
avoid excessive consumption of carbon. Fur
thermore, since there is practically no carbona
,
8. In my process, I avoid the diiiiculty incident
to the separation of the chlorides of iron and
titanium. Furthermore, since TlF4 is stable in
water solutions, no difficulty is encountered in the 65
later stages of purifying the TiO: by means of
'
A speci?c example of carrying out my process
is as follows:
_
70
100 parts by weight of ground ilmenite is mixed
‘with 6 parts by weight of ground charcoal. The
mixture is placed in a furnace, preferably of the
rotary type, and heated at about 900° C. for one
ceous material present during, the chloridization. hour. Chlorine is then introduced into the fur
75 step in my process, I avoid the tendency toward nace while the temperature is maintained at 700 15.
aisaeoe ,
3
to 800° C. I have been able to obtain good results
when the chloridization, is conducted through the
titaniferous material for removal of iron there
from by treating titaniferous material with a
entire range of temperature from 450 to 900° C.
However, I prefer to chloridize at not lower than
350° C. nor higher than 1000° C. When FeCls
proportion to the iron of the titaniferous material
and at a temperature below 1000° C. but suffi
ceases to be evolved, the chloridizing is discon
quantity of carbon in ‘substantially stoichiometric
ciently high to reduce to metal substantially all
, iron compounds in said material and then selec
tinued and the material allowed to cool.
The cooled residue weighing about 50 parts‘by tively'forming ferric chloride from the metallic
weight’ contains'npproximately 94% T102 and " iron and volatilizing the ferric chloride thus
formed by subjecting the reduced material to the 10
‘
_- ‘
"
This residue is then treated with trauma and, action of chloriclizing gas at a temperature above
350° C. and below 1000° C. Y.
placed in acidulated water. The complex tita
3. In a process of making titanium oxide from
. nium salt is leached from the residue and the
liquid bearing this titanium salt is treated with oxides of'iron and titanium, treating the titanif- ,
erous material with a quantity of carbonaceous 15
15 ammonium sulphide which precipitates any iron
which has gone into solution. The iron sulphide reducing agent and at temperature below l000°
is removed by filtration. The ?ltrate is then C. but sumcien-tly high to reduce to metal sub
stantially all iron compounds in said material,
treated with Nil-140B.’ which precipitates the tita
said quantity of carbonaceous ‘reducing agent.
nium as titanium hydroxide. The titanium hy
being suilicient to reduce to metal at least 96% of 20
20 droxide is ?ltered from the solution' and then
calcined. This calcined material is a high quality the iron content but insufiicient to effect reduc
tion of more than a negligible part of the tita
T102 and practically free from iron.
In carrying out the reduction of ferric oxide to nium-content of the titaniferous materialnthen
4% F420.
metallic iron, I may use other carbonaceous re
ducing agents, such as coal, coke, oil, tar, hydro
carbons, etc. in lieu of the charcoal. Caldng of
- the material should be prevented.
selectively‘ forming‘ ferric chloride from the
metallic iron and volatilizing the ferric chloride 25
thus formed by subjecting the reduced material
I prefer a ' to the action. of chloridizing gas at a temperature
muffle type rotary kiln, because this eiiects inti
above 350° C. and below 1000° C.
m
4. In a‘process of making titanium oxide from
mate ‘contact between the carbon and the iron,
30
and if the chloridization be also carried out in oxides of iron and titanium, treating‘the titanif
this kiln, very satisfactory intimate contact be ' erous material with a quantity of carbon in sub
tween the iron and the chlorine is also e?ected. stantially stoichio'metric proportion to the iron of
The kiln is vented‘ to the atmosphere during the. the titaniferous material and ate temperature
. reduction step. If desired, the residue obtained; below 1000° C. but suiiiciently highgto reduce to
by vthe reduction may be transferred from the
metal substantially all iron compounds in said ‘
. The steps of my process heretofore described
material, then selectively forming ferric chloride
from the metallic iron and .volatilizing the ferric
chloride thus formed by subjecting the reduced
for the treatment of titaniferous material to re
40 cover 'I‘iOz are also applicable to the treatment
of zirconiferous material for the recovery of ZrOz.
temperature above 450° C. andobelow 900° C.
5. In a process of making titanium oxide from
' kiln where reduction occurred to another furnace
where the chloridization will be carried out.
material to the action of chloridizing gas at a
oxides of iron and titanium, treating the titanif- I
In the following claims, the expression "sub
stantially all” is employed in de?ning the degree . erous material with a quantity of carbon in sub
of reduction of iron compounds to metallic iron .\ stantially stoichiometric proportion to the iron of 45
the titaniferous material and at a temperature
45 and is intended to cover reductions to the extent
below 1000’ C. but sumciently high to reduce to
metal substantially all iron compounds in said
material, then selectively forming ferric chloride
metal condition.
'
"‘
The present invention is not limited to the from the metallic iron and volatilizing the ferric
speci?c
details set forth in the foregoing ex-' chloride thus formed by subjecting the reduced
50
amples which should be construed as illustrative material to the action of chloridizing gas at a
and not by way of limitation,'and in view of the ~temperature above 350° C. and below 1000° C.,
‘numerous modi?cations which may be effected converting the titanium oxide in the residue into
therein without departing from the spirit and complex salt containing titanium and fluorine, 55
dissolving'the salt, precipitating as a sulphide
55 scope of this invention, it is‘ desired that only
where the unreduced material \will contain no
more than 4% of iron~ in the unreduced, non
such limitations be imposed as are indicated in»
the appended claims.
any iron present in the solution, removing the
' precipitated iron sulphide, forming titanium hy
droxide from the'titanium salt in the solution,‘
1. In a. process of making titanium oxide from‘ ‘and then calcining the titanium hydroxide to
60 oxides‘of iron and titanium, treating the titanif _ produce {titanium oxide.
6. In a process of making titanium oxide from
erous material with- a‘ quantity of carbon and
at temperature below 1000° C. but su?iciently oxides of iron and titanium, heating theti
' high to reduce to metal substantially all iron taniferous material with a carbonaceous reduc
ing agent at temperatures below _1000° C. but
compounds in said material, said quantity of car
I claim as my invention:
65
bon being su?icient to reduce to metal at least
96% of‘ the iron content but insu?icient’ to e?’ect
reduction of more than a negligible part of the
titanium content of the titaniferous material,
then selectively forming ferric chloride from'the
70 metallic iron and volatilizing the ferricchloride
thus formed- by subjecting the reduced material
to the action of chlori'dizing gas‘ at temperature
above 450° C. and below 900° C.
75
.
su?iciently high to‘ reduce to metallic iron sub
stantially all iron compounds in the titaniferous
material, said quantity of carbonaceous reducing ‘
agent being suf?cient to reduce to metal at least
96% of the iron content but insuf?cient to effect
reduction of more than a negligible part of the
titanium content of.the titaniferous ‘material,
removing any remaining carbonaceous reducing
material from the reduced mass, subjecting the
2. In a. process‘of making titanium oxide from ‘ resulting mass to the action of a chloridizing gas
at temperature‘ above 350‘? C. and below 900° C.
oxides of iron and titanium, conditioning the
2,120,002
and for a su?lcient length of time to form ferric
chloride from the iron present in the mass and
to volatilize the ferric chloride thus formed, col
lecting the evolved ferric chloride, treating the
CH residue with a member-of the group composed of
ammonium ?uoride and ammonium bi?uoride at
Y a su?‘iciently high temperature to convert the
titanium oxide therein to 'a complex salt con
taining titanium and ?uorine which is soluble
10 in water but below the temperature at which the
complex salt volatilizes, dissolving the salt ‘from
?cient to reduce to metal. at least 96 per cent
of the iron‘ content but insu?icient to effect re
duction of more than a negligible part of the
oxide of the member of said group consisting of
titanium and zirconium, then selectively form
ing ferric chloride from the metallic iron and
volatilizing the ferric chloride thus formed by
subjecting the reduced material'to the action of
chloridizing gas at a temperature above 350° C.
10
and below 1000° C.
9. In a. process of making zirconium oxide from
‘the mass,~ treating the solution containing the
oxides of iron and zirconium, treating the zir
titanium salt with a sulphide to precipitate any
iron present in the solution, removing 'the pre
coniferous material with a quantity of carbon
aceous reducing agent and at temperature below
1000’ C. but su?iciently high to reduce to metal 15
substantially all iron compounds in said material,
said quantity of carbonaceous reducing agent
being su?icient to reduce to metal at least 96%
cipitated iron sulphide, then precipitating ti
tanium hydroxide from the remaining solution,
removing ‘the precipitate and then calcining to
produce titanium voxide.
.
'7. In a process of making titanium oxide
20 from oxides of iron and titanium,_ heating the
titaniferous material with carbon in substantial
ly stoichiometric proportion to the iron-of the ti
rtaniferous material and at temperatures below_
1000" ‘C. but suf?ciently high to reduce to metallic
25 iron substantially all iron compounds in the
titaniferous material, removing any remaining
of the iron content but insuiiicient to effect re
duction of more than a negligible part of the
zirconium content of the zirconiferous material,
20'
then selectively forming ferric chloride from
the metallic iron and volatilizing the ferric chlo
ride thus formed by subjecting the reduced ma
terial to the action of chloridizing gas at a tem-. 25
perature above 350° C. and below 1000° C.
10. In a process of making zirconium oxide
carbonaceous reducing material ‘from the reduced - from oxides of iron and zirconium, treating the
mass, subjecting the resulting mass to the action
of chlorine gas at temperature above 450° C.
'30
and below 900° C. and for a sufficient length of
time to form ferric chloride from the iron present
zirconiferous material with a quantity of carbon
and at temperature below 1000“ C. but sufficiently 30
high to reduce to metal substantially all iron
compounds in said material, said quantity of' car
in the mass and to volatilize the ferric chloride _ bon being‘vsu?icient to reduce to metal at least
thus formed, collecting the evolved ferric chlo
96% of the iron content but insu?icient to effect
ride, treating the residue with a member of the reduction of more than a negligible part of the
35
group composed of ammonium ?uoride and am- ~ zirconium content of the zirconiferous material,’
monium bi?uoride at a sufficiently high tempera
then selectively forming ferric chloride from the
ture to convert the titanium oxide therein to a metallic ironv andvolatilizing the ferric chloride
complex salt containing titanium and ?uorine thusformed by subjecting the reduced material
which is soluble in water but below the tempera
to the action of chloridizing gas at temperature
40
ture at ‘which the complex salt volatilizes, dis- . above 450° C. and below 900° C.
solving the salt from the mass, treating the,
solution containing the titanium salt with a sul-
phide to precipitate any iron present inv the solu
tion, removing the precipitated iron sulphide,
then precipitatingtitanium hydroxide from the
remaining solution, removing the precipitate and
'
11._ In a process of making zirconium oxide
from oxides of iron and zirconium, conditioning
the zirconiferous material for removal of iron '
therefrom by treating zirconiferous material with
a. quantity of carbon I in substantially stoichio
metric proportion to the iron of the zirconiferous
then calcining to produce titanium oxide.
' ' material and at a temperature below 1000° C. but
8. In a process for- treatingoxides of iron and s'u?iciently high to reduce to metal substantially
a. member'of the group consisting of titanium and
59. zirconium, subjecting the oxides to the action of
a su?icient quantity’ of carbonaceous reducing
all iron ‘compounds in said material and then
selectively forming ferric chloride from the me
tallic iron and volatilizing the ferric chloride thus
agentgat a temperature below 1000° C. but suf . formed by subjecting the reduced material to the
?ciently high to reduce to metal substantially action of chloridizing gas at a temperature above
I I‘ all iron- compounds in said material, said 01BX1- , 350° C. and below 1000“ C.
55 tity of carbonaceous reducing agent being suf-_ _ .
KENNETH HUIWE DONALDSON.
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