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Chapter 4
AVAILABILITY, PROCESSING, AND SPECIFICATIONS
OF TITANIUM ORE AND TITANIUM TETRACHLORIDE
Titanium ore reserves are abundant and widely distributed throughout
the world (Figures 7 and 8~. U.S. self-sufficiency in titanium ore has
declined from 75 percent in the mid-1960s to 45 percent in 1980 because
of the ready availability of low-cost concentrates from other countries
rather than from a lack of U.S. reserves. In terms of contained
titanium, the manufacture of titanium dioxide (TiO2) in the United
States is about 15 times greater than the production of titanium metal.
An emergency need for additional raw material for metal manufacture could
be met readily by diversion of ore, or of titanium tetrachloride , from
the THOU industry. Ore cost, about $0.35 per lb of contained titanium,
is a minor part of the price of titanium metal. A potentially large U.S.
supply of titanium ore occurs in of f-grade deposits and possibly
by-product sources but inadequate technology currently makes their use
uneconomical. Development of suitable processes for utilizing such
abundant domestic resources could be economically rewarding.
Ti tanium Ores
A 1972 report of the National Materials Advisory Board Committee on
Processes for Rutile Substitutes identified the geologic occurrence,
reserves, and principal mines for titanium ores. It discussed the
technology for converting the nonrutile ores to rutile-like material for
use in manufacturing titanium tetrachloride (TiC14), the basic feed
material in preparing titanium metal. TiC14 also is a transitional
material in the manufacture of much of the domestic, and the world's,
TiO2, which is used mostly in paint pigments and as filler in paint,
paper, plastic, and rubber.
In substance, the NMAB group concluded that, since the TiO2
manufacturing industry in the United States was about 15 times larger (in
terms of contained titanium metal) than the metal production industry,
diversion of TiC14 or TiO2 to metal manufacture could be accomplished
readily. The group also concluded that deposits of ilmenite ore in the
United States and Canada were ample for metal production in the
foreseeable future and that research into new methods for preparing
rutile substitutes for metal production was not required at that time.
The report recognized, however, that only Australian concentrate then was
being used in the U.S. production of sponge. (It remains the major source
material in 1981.)
23
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24
it_
Wr-1 ~
1 ~ 3 -
~IF,_,
h I',
=_ _, ;
. A__ __
., ~
~ ,
1 t~.~.=
~ f_,~.,
~--
~ i
L41 I, . - __ _=
- 1 -'' ' ' 1
I.-. ~
A. _ _ :_ ~S
~2 /
arm.],
;,.,
.)
Figure 7 Location of important titanium ore bodies in the
Uni ted States .
Source: DoD Metals ant Ceramics Information Center 1981.
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25
- i:D
me
.
~: ,.~
see ·71 ~
° - _:
o
err
037~- ~-~
~,3
Figure ~ Location of important titanium ore bodies.
Source: DoD Metals and Ceramics Information Center 1981.
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26
The remainder of this section summarizes and brings up to date the
findings about titanium ore supply and ore processing contained in the
1972 NMAB report. Unless otherwise identified, data for this chapter
were drawn mainly from the U.S. Bureau of Mines Minerals Yearbook
1978-1979 and 1980.
Current Ore Supply
The major change in the titanium ore situation since the 1972 NMAB
report was written has been a large increase in the manufacture, both
domestically and abroad, of rutile substitute from ilmenite. However,
the following visible changes could have a significant impact on the
titanium ore supply in the future:
1. Production of natural rutile has declined in the United States,
has leveled off in Australia, and has increased in South Africa
and Sierra Leone. Small-scale production of rutile has started
in Sri Lanka (Ceylon) at the rate of 14,000 tons per year (tpy),
large-scale production of rutile has resumed in Sierra Leone
with a target of 110,000 tpy, and large-scale production of high
titania slag from ilmenite has started in South Africa (about
400,000 spy).
2.
Florida reserves of beach sands, which are the source of the
ilmenite-leucoxene-rutile concentrate used by the major U.S.
manufacturer of TiO2 via the TiC14 route, have continued to
shrink.
New potential by-product sources of titanium have emerged.
These include recovery of accessory minerals from Athabasca
(Canadian) tar sands, recovery of TiC14 or TiO2 from
possible future chlorination of bauxite or clay in the
preparation of aluminum chloride f or the Alcoa aluminum chloride
system now in a demonstration-plant phase, recovery of rutile
from porphyry copper ores, and recovery of ilmenite from the
tails of a sand-clay operation in California.
Additional drilling and laboratory testing of samples has been
done to delineate the potential of a perovs kite (calcium
titanate) ore body in Colorado that appears to contain about 400
million tons of material at a grade of 12 percent TiO2.
U.S. dependence on foreign titanium ores has been increasing and
imports now account for about 55 percent of consumption. In view of the
long lead times (commonly from S to 15 years) needed to bring a new ore
source or technology into production, the current panel believes it
prudent to identify factors and developments in ore supply that may
influence the future availability of titanium ores to U.S. industry. To
present these findings in proper context, ore occurrence, resources, and
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production operations and data are summarized; trends and developments
that may have a bearing on future ore and related metal supply are
identified; and ore processing to TiC14 or TiO2 and production
statistics from concentrate to metal are presented. (The technology of
alternative routes for manufacturing titanium metal from TiC14 or ether
intermediate materials is discussed in Chapter 5.)
Ore Occurrence
Commercial ores contain titanium in the forms of ilmenite (FeTiO3
with S2.7 percent TiO2), altered ilmenite (with up to about 65 percent
TiO2), leucoxene (highly altered ilmenite with up to about 90 percent
TiO2), and rutile (TiO2~. Anatase, another crystal form of TiO2,
is soon to become a commercial source material. Commonly occurring
noncommercial minerals are perovskite (CaTiO3 with 58.9 percent TiO2)
and sphene (CaTiSiOs with 40.8 percent TiO2~.
Resources and Concentrate Production
As c lassified by the U. S . Bureau of Mines and the U. S . Geological
Survey (1980), "reserves" are deposits capable of yielding economic
concentrates under current economic conditions with present technology.
"Other resources" are those deposits containing titanium minerals in such
form and grade as to be reasonably considered a source of titanium for
the future. About 29 million tons of U.S. resources are in a Gunnison
County, Colorado perovskite deposit for which suitable processing
technology still has to be demonstrated.
By-product sources of titanium concentrate, currently of small
consequence, could make important contributions to production if suitable
technology can be developed. Mining and processing technology for
conventional ilmenite and rutile deposits have changed little in recent
years except for the techniques of making artificial rutile that are
still being modified.
Reserves and Resources
World ilmenite and rutile reserves (Figure 8) and producing countries
as of 1979 are identified in Appendix E (Tables E-1 and E-2). U.S.
reserves and resources (Figure 7) also are listed by state in Appendix E
(Table E-3).
It has been estimated that U.S. reserves of 17 million tons of
titanium in ilmenite and 1 million tons in rutile are sufficient to meet
U.S. d~mands to 2000. If imported concentrates continue to provide about
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5 5 percent of U. S . titanium consumption, the U. S. reserves will last much
longer. Total estimated world reserves of 301 million tons of titanium
are over four times the estimated 1978 to 2000 world demand of 64 million
tons. The demand for titanium metal is only about 7 percent of total
titanium demand; therefore, it is not likely to cause any rapid depletion
of reserves . On the contrary, stocks of ilmenite and rutile maintained
for pigment manufacture could provide an emergency supply of f eed
material for metal production.
World titanium capacity and production for 1978 are displayed in
Table 1 f or concentrates of ilmenite, rutile, synthetic rutile, sponge,
and titans pigment. U.S. production of ilmenmite and rutile concentrate
peaked at about 32S,000 tons of contained titanium in the mid-1960s.
Only about 70 percent as much titanium in concentrate has been produced
annually since 1971. As noted in the introduction to this chapter, this
is due to economics and the ready availability of foreign ores and not to
any lack of domestic reserves.
Outside of the United States, the reserves in Canada, Finland, Norway
and most of those in the USSR are in hard-rock deposits of
ilmenite-hematite and ilmenite-magnetite. The remainder of the world's
reserves are almost entirely in beach-sand deposits. U.S. reserves are
about 40 percent in the hard-rock iLmenite in New York and 60 percent in
beach-sand deposits. Concentrates from the beach sands, but not from the
New York ilmenite, are amenable to direct chlorination for TiC14
production. However, only one company, a pigment manufacturer, has been
using ilmenite as a direct chlorination feed material.
Those titaniferous magnetite deposits for which suitable processing
technology has not been demonstrated are included in the resources
columns in Table 1. Frequently, the complexity of the mineral assemblage
and the degree of interlocking in these deposits does not permit ready
preparation of marketable concentrates by conventional beneficiation
techniques. Illustrative of this type of deposit are the titaniferous
magnetites in Minnesota and Wyoming. Neither economics nor shortages of
re serves have been sufficient to stimulate the massive research needed to
develop methods for recovering titanium from such lower grade resources.
Past and current efforts on such domestic resources, motivated by
shifting views of the desirability for U.S. self-sufficiency in critical
materials, have been mostly of a desultory nature. Recent research is
reviewed below.
Hardrock Ilmenite Depo sits
Conventional open-pit mining is used at three of the world's ilmenite
rock deposits--Allard Lake, Canada; Tahawns, New York; and Tellnes,
Norway. Underground mining is used at Otanmaki, Finland. Except for
Allard Lake ore, crushing and grinding is followed by combinations of
gravity, magnetic, and flotation techniques to produce concentrates of 45
to 47 percent TiO2. Allard Lake ore at 32 to 36 percent TiO2 is concentrated
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TABLE 1. World Titanium Capacity sud Production, 1978 (in short tons t$tanlum content)
Ilmeni te Rutile
-
Ruti le Synthetic
Caps- Capa- Capa
city Prod ' n city Prod 'n city Prod 'n
Sponge Plgment
Capa- Capa
city Prod 'n city Prod ' n
No rth Ameri ca
Unitee ~tates 31s 218 1" ~60 1(3 23 16 ~523 420
Canada 525 399 - - - - - - 64 NA
Mexico _ _ _ _ _ ~ _ _ 22 NA
Sotal 843 617 14 W 60 10 23 18a 609 NA
South America, Brazil 8 7 (b) (~) - _ _ _ 22 NA
Europe
Finland 51 3 9 - - - - - - 5 3 NA
France - - - - - - - - 94 NA
Germany, Fet. Rep. - - - - - - - - 212 NA
Norway 280 228 - - - - - - 17 NA
United Kingdom - - - - - - 3 2 16S 136
Soviet Union 124 121 7 6 - _ 42 39 82 NA
Other _ _ _ _ - _ _ _ 195 NA
, 7 6 - - 45 41 818 NA
Total 455 288
Africa, South Africa,
Rep. of, and Asia 112 51
India 80 58
3apan ( b) ( b)
Malaysia 75 67
S2~t Lanka 35 13
Taiwan
Other
35 11 - - - - 18 NA
5 3 17 NA - - 8 NA
- - 32 25 13 10 143 113
3 4 - - _ _
8 ? - - - - _ _
- - 17 NA - - 3 NA
- - _ _ _ _ 20 NA
lotal 190 138 13 10 100 25 13 10175NA
NORLD TOTAL 2,148 1, 666 294 188 195 6S 81 691, 6841, 400
NA - Not available
a - Calculatet: Productlon - consumptlon - imports ~ stock changes.
( b) - Less than one-half unit.
Source: Mlneral Facts and Problems, U.S. Bureau of Mines 1980.
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by gravity methods and the concentrate is roasted to eliminate sulfur and
then smelted with coke in an electric furnace. Most of the iron is
selectively reduced to a marketable pig iron. The titanium goes into the
slag with ~ 70 to 72 percent TiO2 content that, because of its low iron
content, is a preferred feed for manufacturing TiO2 pigment by the
sulfation route. Conversely, because the slag contains MgO (5 percent)
and CaO (l percent), which form troublesome sticky phases when
chlorinated, the slag is considered undesirable for direct chlorination
to TiC14.
BecaXrSand Deposits
Mining of fossil beach sand containing ilmenite, leucoxene, and
rutile is accomplished by dredges or draglines, usually the former.
Heavy minerals initially are separated from the quartz-feldspar-mica
fraction of the sand using spirals or cones. Jigs sometimes are used on
stream type placers that contain a large range of particle sizes. The
heavy sands are dried and an ilmenite-rutile fraction is made on
electrostatic equipment. The titanium minerals then may be further
separated into an ilmenite-leucoxene fraction and a rutile fraction
removed by high-intensity magnetic equipment.
Depending on the degree of ilmenite alteration, ilmenite (and
leucoxene) concentrates from beach sand have TiO2 contents ranging from
45 to 50 percent, the same as in rock ilmenites and in the South African
sand ilmenite; f ram 54 to 70 percent in Australian, Indian, and U.S.
altered ilmenites; and from 70 to 90 percent in Australian leucoxene.
Perovskite Deposits
The perovskite deposit In Gunnison County, Colorado, reported to
contain lOO million tons of 12 percent TiO2 measured ore and 400
million tons of 12 percent TiO2 indicated and inferred ore, is close to
the surface and presumably mineable by open pit methods (Thompson and
Watson 1977~. Results of beneficiation testing have not been released.
Laboratory tests to prepare titanium carbide from a sample of
perovskite concentrate have been conducted by the U.S. Bureau of Mines
(Elger et al. 1980~. However, prolonged fusion in an electric furnace to
form TiC4 and calcium carbides is inordinately expensive in terms of
e quipment and power requirements. Thus, this technology is not promising
as an economical route to utilizing pervoskite concentrate.
Potential By-product Sources of Titanium Concentrate
Recovery of ilmenite from tin dredging in Malaysia is the only
current by-product production of titanium minerals. Other potential
sources are the "red mud" wastes from processing bauxite ore for alumina
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and from a conceptual process for chlorinating bauxite to prepare AlC13
for electowinning of aluminum; porphyry copper mill tailings; sand and
gravel, gold placer, and silica-c lay operations; and tar sands
operations. Of these, Canadian tar sands and waste tails from a
silica-clay operation in California offer the best prospects for
by-product titanium in the next several years should the need for
alternative sources arise.
Po ssible recovery of titanium f ram red muds containing 4 to 11
percent TiO2 was discussed in the 1972 NUMB report . About 300,000 to
4 00, 000 tons of TiO2 are contained in the muds discarded each year in
the United States. Technology for economic recovery of the titanium they
contain has yet to be developed and demonstrated.
Bauxite ores contain 1 to 6 percent TiO2. If electrowinning of
aluminum by the chloride route, as is now being tested by Alcoa, becomes
commercial and if direct chlorination of bauxite becomes the established
route for preparing the aluminum cell feed, the by-product recovery of
TiC14 from chlorinating bauxite or clay to make AlC13 with recovery
of TiO2 or TiC14 would be likely. A process developed by the Toth
Aluminum Corporation for chlorinating bauxite or clay with recovery of
TiC14 or TiO2 has been described (U.S. Environmental Protection
Agency 1976~.
Most of the porphyry copper ores contain 0.3 to 0.75 percent TiO2,
largely as rutile. Essentially all of the contained TiO2 is found in
the finely ground mill tailings that are discarded after the copper and
molybdenum are selectively floated. Laboratory research to recover the
rutile was done on a sample of tailings from Arizona containing 0.75
percent TiO2 (Llewellyn and Sullivan 1980). By a complicated procedure
involving desl iming, flotation and rejection of sulfides and carbonates,
acidulation, and flotation and cleaning of rutile concentrate, about 37
percent of the TiO2 was recovered in a concentrate of 35 percent TiO2
grade. This recovery of 5 to 6 lbs of rutile in a low-grade product from
a ton of originally alkaline tailings would fall far short of paying the
operating costs. With present technology, the outlook is dim for
by-product titanium from copper tailings.
Possible recovery of titanium concentrate from West Coast sand and
gravel operations and gold placers recently was investigated by the U.S.
Bureau of Hines (Gomes et al. 1979 and 1980; Martinez et al. 1981~.
Results of laboratory tests are reviewed in Appendix E. A silica-clay
operation in California that has tailings containing about 20 percent
TiO2 may have the potential for titanium by-product recovery.
Syncrude Canada, Ltd., operates an Athabaska tar sands plant for
recovery of a scheduled 105,000 barrels of oil per day from tar sands
containing 9 to 16 percent bitumen. A hot water extraction process is
used. After extraction and discard of the primary tails, bitumen is
diluted with naptha and centrifuged to remove entrained solids, which
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also are discarded. These centrifuge tailings have been found to contain
about 7 percent TiO2 representing a recovery of about 85 percent of the
TiO2 in the tar sands feed. In laboratory tests, the entrained bitumen
was burned off and the oil-free sands were treated on spirals and
electrostatic and magnetic equipment to make a product grade of about 69
percent TiO2 . The concentrate was observed to be highly weathered and
tests indicated that separation could be made of ilmenite, leucoxene, and
rutile concentrates.
A possible annual production of 85,000 tons of titanium concentrate
from the Syncrude plant was projected. This might be doubled if the
centrifuge tails f ram the nearby Suncor tar sands plants were combined
with the Syncrude centrifuge tails for treatment. Market and economic
studies are being made by Syncrude to determine the feasibility of
titanium minerals production (Trevory and Shuttle 1981~. Information
about the titanium minerals potential of Utah tar sands is, as yet,
lacking .
Synthetic Rutile
Titanium tetrachloride, for the manufacture of titanium metal or
titanic pigment, historically has been made in the United States by
chlorination of rutile concentrate of about 96 percent TiO2 grade.
Increasing world demand and shrinking reserves caused a steep escalation
of rutile concentrate prices that resulted in the development of
processes and the construction of plants for converting ilmenite
concentrate to synthetic rutile. Although ilmenite concentrate and slags
made f ram ilmenite can be chlorinated directly, high operating,
purification, and waste disposal costs in U.S. practice favor preliminary
upgrading of the chlorinator feed material to rutile substitutes.
Various processes for upgrading ilmenite concentrate were reviewed in
the 1972 XMAB report. Those in use all involve a reductive roast, an
acid leach, or artificial accelerated weathering. Frequently, an
oxidizing roast is employed to convert extracted impurities back to the
oxide with recovery of the hydrochloric acid used in leaching. All these
processes pose the possibility of more or less severe environmental and
waste disposal problems and costs, depending on the location, f eed
material, and process used.
Curre nt Prac Lice
Commercial plants in India, Japan, Malaysia, Taiwan, and the United
States are designed to partially reduce the iron in the ilmenite and then
remove much of the iron along with part of the magnesium and calcium by
leaching with acid. One plant in Australia reduces the iron to the
metallic state and then re-oxidizes it irr a water slurry for its removal
as a hydrated oxide.
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Kerr-McGee at Mobile, Alabama, makes synthetic rutile for use in its
titanium pigment plant at Hamilton, Mississippi, and for sale. Ilmenite
concentrate at a grade of about S9 percent TiO2 from Australia is the
feed to the upgrading plant. Production was at a rate of 80,000 to
85,000 tpy in mid-1981 and was scheduled for 110,000 tpy in 1982.
Slag of 85 percent TiO2 grade made f rom Richards Bay, South Africa,
sand concentrate is low enough in magnesium, calcium, and manganese to be
considered as a rutile substitute suitable for direct chlorination. U.S.
imports of South African slag, another rutile substitute, were 30,000
tons in 1979 and 50,000 tons in 1980. Major U.S. imports of synthetic
rutile in 1980 were 61,000 tons from Australia, 10,000 tons from India,
and 7, 000 tons f rom Japan.
S1 ag Benef ice ation Research
Laboratory work on benef iciating titanium slags that are too impure
for direct chlorination is being done by the U.S. Bureau of Mines (Elger
et al. 1981~. The slag, made from domestic ilmenite, is
sulfa/ion-roasted and then leached to remove solubilized calcium,
magnesium, and manganese. Early data show that most of the calc ium and
manganese and 70 percent of the magnesium were removed from the slag.
The process is in an early stage of development and is not ready for
assessment .
TiO2 Pigment and TiC14
TiO2 pigment, a highly purif fed f arm of rutile or ana~case, is
prepared by processes involving the sulfuric acid digestion or the
chlorination of titanium dioxide concentrates. TiC14 that is of
adequate purity to yield pigment TiO2 ordinarily must be further
purified to be suitable for the manufacture of titanium metal sponge by
any of the three commercial routes--magnesium, sodium, or electrolytic
reduction. TiO2 pigment, when mixed with carbon, is readily
chlorinated to make TiC14 suitable for reduction to metal, but this is
not done commercially. U.S. pigment production was 700,000 tons in 1978
and 714,000 tons in 1980. (Production and purchasing specifications for
TiC14 offered or desired by several U.S. firms and by the Soviet Union
are included in Appendix F. World capacity and production of pigment for
1978 is shown in Table E-1 of Appendix E.
TiO2 Via Sulfuric Acid Digestion
Ilmeni te concentrate or titanium slag is digested in sulf uric ac id .
Any Fe+3 present is then reduced to Fe+2 by addition of scrap iron;
part of the ferrous sulfate is crystallized and removed; the titanium
hydroxide i s precipitated by hydrolysi s, f iltered, and f inally calcined
to the oxide. The process is tolerant of low-grade and impure feed
material except that excessive chromium, phosphorous, niobium, manganese,
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and vanadium degrade the pure white color of the pigment.
suffers from a difficult and costly sulfate-waste disposal
existing U.S. plants using the sulfate process are capable
250,000 tons of pigment per year.
TiO2 Via TiC14
The process
problem. The four
of manufacturing
U.S. practice for making TiO2 for pigment involves the chlorination of
ru tile or synthetic rutile concentrate in the presence of petroleum coke in
fluid-bed reactors at 850 to 950°C. Iron, aluminum, and silicon oxides also
react to form volatile chlorides. These and other impurities that form
volatile chlorides are separated from the TiC14 by fractional
distillation. Vanadium is removed from liquid TiCl4 by adding copper to
form a precipitate of copper vanadyl chloride. Purified TiC14 vapor then
is burned with air or oxygen under controlled conditions and with selected
additives to make TiO2 of the required particle size and form.
The process is intolerant of more than minimal magnesium, calcium, or
manganese in the feed. These form troublesome liquid phases in the
chlorinator that cause plugging dif f iculties on cooling when they leave the
reactor. Environmental and waste disposal factors are considered less
troublesome when using suitable lo~impurity feed. The nine existing U.S.
plants using the chlorination process are capable of manufacturing about
800,000 tons of pigment per year.
Price Comparison of Titanium Materials
Table 2 indicates that the ore cost of titanium, even of its most
expensive form (natural rutile), is a minor part of the sponge price.
TABLE 2 Price Comparison of Titanium Materials
Commodity
Median
Price of
contained
Price Ti (~/lb)
.
Ilmenite, long ton, 54 percent TiO2, fob Atlantic portsa $65-70 lo
Slag, long ton, 70 percent TiO2, fob Quebec, Canada a 6135 14
Slag, long ton, 85 percent Ti02, fob South Africat $170-180 15
Synthetic Rutile, 93.5 percent TiO2, st, fob Mobile, Ark $340 30
Rutile (natural), short ton 96 percent Ti02, fob Atlantic
and Great Lakes Portia
Pigment, lb, rutile, TiO2 c
Sponge, lb, 99.3 percent Ti, max. 115 Brinell a
Sponge, lb, Japanese, 99.8 percent Ti, 97-99 Brinelll
Titanium tetrachloride, lbC
a Engineering & Mining Journal, June 1, l9X1.
b U.S. Bureau of Mines 1981.
c Chemical Marketing Reporter 1981.
$450-475 40
$0.69 115
$7.22 727
$8.85-10.03 946
$0.35 40
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Appraisal of Exploration, Mining, and Concentrating Technology
Theories of titanium ore deposition and criteria for finding titanium
deposits have been developed and discussed (Force 1978). Well-established
techniques for surface and underground mining exist and are readily
modified for local conditions and variations in ore occurrence.
Similarly, beneficiation practices have the flexibility to handle widely
different assemblages of titanium and accessory minerals in beach-sand
deposits. Massive ilmenite-magnetite deposits are amenable to physical
beneficiation using conventional gravity, flotation, and magnetic
procedures provided that discrete mineral particles can be liberated
without excessively fine grinding. A combination of physical
beneficiation and smelting has proved applicable to the massive
ilmenite-hematite deposits at Allard Lake, Canada. Overall, the
relatively low prices of $0.10 to $0.15 per lb of titanium in ilmenite and
slag concentrate and of $0.27 to $0.40 per lb of titanium in synthetic and
natural rutile concentrate indicate the efficacy of ore finding, mining,
and concentrating practices.
Ilmenite-magnetite ores of suitable grade that are not amenable to
beneficiation by physical means may be smelted to produce titanium slag
and pig iron. However, practicable technology is lacking for utilization
of lower grade ilmenite-magnetite ores with tightly locked mineral
components, (e.g., those from the Iron Mountain deposit in Wyoming).
Plausible new ideas are needed to justify additional research to f ind
feasible extraction processes for such ores.
Combinations of pyrometallurgical and hydrometallurgical techniques to
prepare synthetic rutile from ilmenite concentrate have been in commercial
use for several years. As operating experience is gained, the expected
incremental improvements should lessen the potentially severe
environmental and waste-disposal problems. Innovative research for direct
preparation of TiC14 from ilmenite concentrate and slag produced from
domestic ilmenite-magnetite deposits seems worth pursuing. The direct
chlorination of ilmenite to TiCl4 and FeC13 followed by fluidized-bed
conversion of the separated FeC13 to C12 for recycling and the
resulting Felon for market has been proposed (Paige et al. 1975~. The
technique was operable in the laboratory, but apparent scale-up
difficulties have discouraged commercial adoption. Concentrate has been
prepared in the laboratory from Colorado perovskite ore by physical
beneficiation, but feasible technology for utilizing the concentrate is
lacking and requires development.
A comprehensive investigation by Syncrude Canada, Ltd., has
established a potential for economic by-product recovery of titanium
concentrate from Athabasca tar sands. In assessing possible by-product
sources of domestic titanium, it would be of interest to know the extent
of available titanium in Utah tar sands.
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Utilization of the large by-product titanium potential of Bayer plant
(aluminum production) red mud and porphyry copper tails requires cheaper
and more effective technologies than now exist. The possibility of
recovering by-product TiC14 f rom chlorination of bauxite or clay in the
aluminum industry depends on the direction taken in the future development
of the Alcoa chloride process.
Other potential by-product sources (e.g., those revealed in the recent
U .S . Bureau of Mines surveys of sand, gravel, and clay plant waste s)
appear to have merit for exploitation with the use of conventional
technology. These could become a source of titanium minerals provided the
individual sources are of suf f icient tonnage and grade to permit an
economical operation.
Specifications for Minerals and Mineral Concentrates
Rutile
Concentrates of the naturally occurring mineral rutile (TiO2) are
the historically preferred raw material for titanium metal production
through the intermediate product, titanium tetrachloride. Rutile
concentrates may be chlorinated in the presence of a Deduct ant (e.g.
petroleum coke), commonly in fluidized-bed reaction vessels, to produce
the tetrachloride. To satisfy the requirements of operation of the
various modifications of reduction-reaction equipment, rutile may be
purchased to specifications that limit particle size and impurity
composition produced by private companies. The U. S. National Stockpile
Purchase Specification P-49-R6, part of which is included in Appendix G.
covers rutile that is satisfactory for use in the production of titanic
metal (via the tetrachloride intermediate product), welding rod coatings,
and f erro-t itanium alloys.
Synthetic Rutile
No public specifications cover the products, generally known as
synthetic rutiles, that result from the upgrading of mineral concentrate s
such as ilmenite and leucoxene by physical and thermal-chemical
processing. The synthetic rutiles may be used in the production of
t itanium tetrachloride f or conver Sian to metal or othe r produc ts . There
are several processes in use for the production of synthetic rutile and
each aims at achieving a 90 to 95 percent TiO2 content while minimizing
iron, calcium, magnesium, and other impurities. Further, physical
properties such as particle size are controlled to within acceptable
limits. The chemical and physical characteristics acceptable to
purchasers are described in purchasing agreements.
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Slags from Ilmenite
Products that are reasonably high in titanium dioxide (e.g., 70 to 90
percent) can be produced from ilmenite by smelting to reduce the iron
oxide content to metal leaving the titanium in the slag as oxide. The
slags may contain as much as 5 to 10 percent residual iron that can be
chlorinated readily, but this reduces chlorinator throughput in terms of
the desired titanium tetrachloride output and also results in a problem
regarding the disposal of the iron chlorides produced. Nevertheless,
slags may be used in the production of titanium tetrachloride when their
availability and economics offer advantages to the producer. There are no
public specifications covering slags produced from ilmenite-type
concentrates that are useful in manufacturing titanium tetrachloride.
However, it is well-recognized that slags for chlorination must be low in
calcium, magnesium, and manganese.
Ilmenite Concentrates
There are no public specifications for ilmenite concentrates suitable
for use in chlorinators for the production of titanium tetrachloride. In
the United States, E. I. du Pont de Nemours ~ Company, Incorporated
operates mining, concentrating, and chlorinating equipment that utilizes
ilmenite concentrates enriched with leucoxene and rutile fractions as feed
stock. The titanium tetrachloride product is used primarily in the
production of titanium dioxide f or pigment, welding rod coatings, and
other uses, but with suitable upgrading by additional distillation, the
tetrachloride produced could be used in the production of titanium sponge
metal.
Specifications Covering Titanium Tetrachloride
Specifications generated by private companies for the purchase of
titanium tetrachloride can be proprietary and therefore not publicly
available . An example of a purchasing specif ication, not held as
proprietary, is given in Appendix F. Producer specifications for titanium
tetrachloride of United States (Cabot Corporation) and Soviet manufacture
also are given in Appendix F. No public specifications exist.
None of the specification information available from U.S. producers
and users of titan) um tetrachloride f or metal production includes the
important data relating to the metal-oxychloride and dissolved gases
contents. In this respect, the Soviet specification is informative. It
shows that the oxygen content in the form of oxychlorides, carbon
compounds, and chlorine and chlorine compounds, other than the titanium
tetrachloride, can be significant. The control of these impurities to low
levels is as important as the control of the metallic impurities to the
product) on of high-quality sponge titanic. It has been stated that an
additional purification step (e.g., additional distillation) is capable of
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rendering a pigment-grade tetrachloride (e.g., the product described by
du Pont ~ suitable for the production of metal . A low oxygen content and a
reduction of other impurities in titanium tetrachloride are requirements
for the production of good-quality sponge titanium metal.
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REFERENCES
Dean, R. S., and B. Silkes, 1946. Metallic Titanium and Its Alloys.
Information Circular 7381. Washington, D.C.: U.S. Bureau of Mines.
De an , R . S ., J . ~ . Long, F . S . Wartman , and E . R . Ander son , 1946 .
Preparation and Properties of Ductile Titanium, Mineral and
Metallurgical Engi peering Technological Publication No. 1961.
Dean, R. S., F. S. Wartman and E. T. Hayes, AIME Transactions,
Vol. 166, 369-381. 1946. Ductile Titanium: Its Fabrication and
Physical Properties, Technical Publication No. 1965. AIME
Transactions, Vo1. 166, 381-389.
Elger, G. W., W. L. Hunter, and E. Mauser. 1980. Preparation and
Chlorination of Titanium Carbide from Domestic Titaniferous Ores.
Report of Investigation RI 849 7 . Washington, D.C.: U.S. Bureau of
Mines .
Elger, G. W., J. E. Tress, R. R. Jordan, and L. L. Oden. April 1981.
Ugrading domestic titaniferous resources for producing titanium.
Paper presented at Pacific Northwest Metals and Minerals Conference,
Portland, Oregon,.
Force, E. R. Some predictive techniques in heavy mineral exploration.
1979. Paper presented at the Society of Manufacturing Engineers
(SHE), American Institute of Mechanical Engineers (ADME) Fall Meeting,
Orlando, Florida, September 11-13, 1978.
Gomes, J. M., G. M. Martinez and M. M. Wong. 1979. Recovering
By-product Heavy Minerals from Sand and Gravel, Placer Gold, and
Industrial Mineral Operations. Report of Investigation 8366.
Washington, D . C .: U . S. . Bureau of Mines .
Gomes, J. M., G. M. Martinez and M. M. Wong. 1980. Recovery of
By-product Heavy Minerals from Sand and Gravel Operations in Central
and Southern California. Report of Investigation 8471. Washington,
D.C. : U.S. Bureau of Mines.
Llewllyn, T. O., and G. V. Sullivan. 1980. Recovery of Rutile from a
Prophery Copper Tailings Sample. Report of Investigation 8462.
Washington, D.C.: U.S. Bureau of Mines.
Martinez, G. M. , J. M. Gomes and M. M. Wong. 1981. Recovery of
By-product Heavy Minerals from Sand and Gravel Operations in Oregon
and Washington. Report of Investigation 8563. Washington, D.C.:
U. S. Bureau of Mines.
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National Materials Advisory Board Committee on Processes for Rutile
Substitutes. 1972. Report NMAB-293 Processes for Rutile
Substitutes. Washington, D.C.: National Academy of Sciences.
Paige, J. I., G. 8. Robidart, H. M. Harris and T. T. Campbell. 1975.
Recovery of chlorine and iron oxide from ferric chloride. JOM,
Vol. 28, 12-16.
Thompson, J. V., and D. L. Watson. 1977. Appraising large diameter core
and percussion drilling for bulk samples. E&NJ Vol. 178 :80-82.
Trevory, L. W., and R. Shuttle. 1981. A New Source of Heavy Minerals
from Canadian Oil Sands Mining Operation. Manufacturing Engineering,
S ME; Preprint 81-20, Dearborn, Michigan.
U.S. Bureau of Mines. 1978-79 and 1980. Minerals Yearbook. Vol. 1,
Metals and Minerals, Titanium. U.S. Government Printing Office,
Washington, D . C.
U.S. Bureau of Mines and U.S. Geological Survey 1980. Principles of a
Resource/Reserve Classification for Minerals. USGS Circular 831.
U.S. Government Printing Office 1980.
U.S. Environmental Protection Agency . 197 6. Environmental
Considerations of Selected Energy-Conserving Manufacturing Process
Options. Report EPA-600/7-76-034h, Vol. 8, Washington, D.C.: U.S.
Environmental Protection Agency.
Representative terms from entire chapter:
titanium ore
