US3735000A - Process for preparing titanium dioxide - Google Patents

Process for preparing titanium dioxide Download PDF

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Publication number
US3735000A
US3735000A US00054715A US3735000DA US3735000A US 3735000 A US3735000 A US 3735000A US 00054715 A US00054715 A US 00054715A US 3735000D A US3735000D A US 3735000DA US 3735000 A US3735000 A US 3735000A
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United States
Prior art keywords
zone
titanium tetrachloride
titanium dioxide
stream
oxygen
Prior art date
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Expired - Lifetime
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US00054715A
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English (en)
Inventor
B Calcagno
L Piccolo
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Societa Italiana Resine SpA SIR
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Societa Italiana Resine SpA SIR
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/07—Producing by vapour phase processes, e.g. halide oxidation
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/51—Particles with a specific particle size distribution
    • C01P2004/52—Particles with a specific particle size distribution highly monodisperse size distribution
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values

Definitions

  • Titanium tetrachloride is oxidised to titanium dioxide in a burner-heated chamber of particular design preventing formation of deposits on the walls and in the feed passages for titanium tetrachloride.
  • This invention relates to a process for the preparation of titanium dioxide by the oxidation of titanium tetrachloride in gaseous phase, by means of oxygen, at high temperature.
  • the high temperatures needed to bring the reaction about are obtained either by preheating at least one of the reagents or by the use of a flame from an auxiliary combustible.
  • the present invention is concerned with those processes in which the reaction takes place in the presence of a flame from an auxiliary combustible, in which the titanium tetrachloride is oxidised to titanium dioxide.
  • titanium dioxide especially as a pigment, for example in papers, varnishes, gums and plastics.
  • a product having special characteristics is required, such as, for instance, those connected with covering power, dispersion, brilliance and so forth.
  • One object of the present invention is therefore a method of oxidising titanium tetrachloride so as to produce titanium dioxide of suitable crystalline structure, such as rutile, in the form of fine particles of regular, rounded shape, of definite diameter within a limited range of values, and free from aggregates.
  • Another object of the invention is a method of oxidising titanium tetrachloride whereby the formation of deposits is avoided in the equipment used, thus making it possible to obtain titanium dioxide having characteristics which remain constant with time.
  • a further object of the invention is a. form of equip-- ment, simple in design and easy to maintain, suitable for the oxidation of titanium tetrachloride, for the production of titanium dioxide having the characteristics already mentioned.
  • the process here proposed consists essentially in bringing into contact, within suitable equipment, a relatively cold stream of gas consisting of titanium tetrachloride and the oxidising gas and a stream of hot gases obtained by burning the auxiliary combustible, this contact being brought about by a special system of flow dynamics.
  • the process here proposed consists in forming within a single chamber (reaction chamber) three distinct zones consisting of: an initial zone, in which what occurs is substantially the burning of the auxiliary combustible (combustion zone); a second zone, in which what occurs is substantially the mixing of the stream of gas consisting of the titanium tetrachloride and the oxidising gas with the stream of hot gases derived from the burning of the auxiliary combustible (mixing zone); and
  • the third zone in which what takes place is substantially the oxidation of the tetrachloride to titanium dioxide (oxidation zone).
  • the reaction chamber comprises an upper zone, cylindrical in shape (combustion zone), communicating with a lower zone, likewise cylindrical, but larger in diameter (oxidation zone), these two zones being joined together by a truncated cone, which constitutes the mixing zone.
  • FIG. 1 is a sectional diagram of the reaction chamber, consisting of the combustion zone 1, the mixing zone 2 and the oxidation zone 3.
  • the top part of the combustion zone 1 contains the burner 4 for the auxiliary combustible or fuel.
  • the combustion zone 1 is cylindrical, its height being such that the flame is substantially spent before contact is made with the titanium tetrachloride.
  • burners of pre-mix type since they enable fairly short flames to be obtained.
  • Possible fuels are: carbon monoxide, hydrogen, methane, acetylene or liquefied petroleum gases. Carbon monoxide is generally preferable, because it does not lead to the formation of hydrochloric acid, which is undesira-ble as a by-product.
  • a basic feature of the process with which the invention is concerned is that the titanium tetrachloride is fed in the form of an annular laminar flow of gas inclined at 30 to 60 to the central stream of hot gases produced by the burning of the fuel.
  • Laminar flow of gas here means flows having a thickness of from 0.1 cm. to 0.8 cm.
  • the titanium tetrachloride fed in through 6 is conveyed into the mixing zone 2 through the annular slit 7 contained in the wall of this frusto-conical zone, the said slit running Substantially at right angles to that wall.
  • the Slope of that wall in relation to the longitudinal center line of the reaction chamber is so determined that the desired angle of impact is produced between the stream of titanium tetrachloride and the stream of hot reaction gases.
  • Another basic feature of the invention is that the oxygen intended for oxidising the titanium tetrachloride is fed in tangentially to the wall of the upper part of the combustion zone.
  • the cold oxygen is fed in through two pipe connections, 5, details of which are brought out more clearly in FIG. 2, which is a section through the reaction chamber at the level of the oxidising gas feed.
  • the flow of oxidising gas follows a path close to the wall until it reaches the zone in which it is mixed with the titanium tetrachloride.
  • This arrangement also protects the feed slit for the titanium tetrachloride from the formation of deposits.
  • the molar ratio observed between the oxygen and the titanium tetrachloride is preferably between 1.15 :1 and 1.421, the oxygen being fed in at or slightly above ambient temperature, at C. to 40 C., for example, while the titanium tetrachloride may suitably be heated to temperatures in no case exceeding 500 C.
  • Oxygen or gases containing more than 90% of molecular oxygen are employed for the oxidation reaction.
  • titanium dioxide In the tetrachloride oxidation reaction in the prior art, the formation of titanium dioxide is known to occur within a temperature range above its flow point, at which it has plasticity, so that it tends to cling to any surfaces with which it comes in contact.
  • Deposits may therefore form on the burner and on the walls of the reaction chamber, especially at points where the reagent substances also make contact.
  • Deposition is also avoided in the feed passages of the titanium tetrachloride, since, as previously stated, the reagents come into contact in that zone at temperatures substantially below the reaction temperature, apart from the protective action of the entry velocity.
  • nucleus-forming agents as, for example, the chlorides of aluminium or silicon or water vapour, it is necessary to establish a system of flow dynamics such as to alford equal conditions for all the particles as regards formation, growth, high-temperature stability and cooling.
  • the same gases as are produced in course of reaction may be used, these being re-cycled at low temperature after dust-extraction.
  • titanium dioxide is separated from the other reaction products and subjected to quality tests for use in pigments, after which it is treated by the usual methods to obtain the finished pigment.
  • the combustion zone was 15 cm. in diameter and 25 cm. long
  • the oxidation zone was 35 cm. in diameter and 120 cm. long and these were joined together by a 45 truncated cone.
  • the chamber was made from refractory material containing 70% to 72% of alumina.
  • the annular feed slit for the titanium tetrachloride was 0.1 cm. wide and was bounded by two walls of nickel, trued and suitably spaced so as to provide a constant aperture round the entire circumference.
  • the burner was fed with carbon monoxide, containing 2% of hydrogen, and oxygen in quantities gradually rising to maximum values of 22.6 N cu.m./hour for the carbon monoxide and 17 N cu.m./hour for the oxygen.
  • the burner was of the pre-mix type and provided a flame which was substantially spent within the combustion zone, so that the gas entered the mixing zone fully combusted.
  • oxygen was fed in tangentially, at the rate of 47 N cu.m./hour, through two pipe connections. fitted at the top of the combustion zone.
  • the oxygen feed path can be seen particularly clearly in FIG. 2.
  • the titanium tetrachloride containing 2% by weight of aluminium trichloride, was pre-heated to a temperature of 400 C. in Inconel heat exchangers and fed in at the rate of 320 kg./hour.
  • the metal halide was fed through an annular slit 0.1 cm. wide, set at right angles to the wall of the frusto-conical zone, the stream of gas emerging at a linear velocity of 33 m./ sec.
  • the stream of titanium tetrachloride was admitted to the mixing zone in a direction inclined at 45 to the axis of the stream of hot gases produced by the combustion of the carbon monoxide.
  • reaction products were cooled to about 300 C. in the delivery pipes from the chamber by re-cycling the reaction gases after cooling and dust extraction.
  • particle size distribution of the particles were of sizes between 0.17 and 0.30 micron, without any aggregates Whatever;
  • crystalline form rutile as to more than 99%
  • the molar ratio maintained between the carbon monoxide and the titanium tetrachloride was 0.3 1.
  • the titanium dioxide obtained had characteristics equal to those in Example 1.
  • the molar ratio maintained between the carbon monoxide and the titanium tetrachloride was 03:1.
  • the titanium dioxide obtained had a Reynolds dye number of 1800 and 80% of the particles had a size distribution of 0.15 to 0.30 micron.
  • the molar ratio maintained between the carbon monoxide and the titanium tetrachloride was 0.2: 1.
  • the titanium dioxide obtained had a Reynolds dye number of 1300 and 80% of the particles had a size distribution of 0.10 to 0.32 micron.
  • titanium dioxide comprising oxidizing gaseous titanium tetrachloride With gaseous oxygen at a high temperature by means of and in the presence of a stream of hot gases produced in a reactor by the combustion of an auxiliary combustible, the improvement comprising avoiding the formation of titanium dioxide deposits in the reactor and obtaining titanium dioxide having characteristics which remain constant with time by a process which comprises:
  • the angle formed between said hot gas stream and said annular stream at mixing being from 30 to 60, said mixing zone being of sufiicient length to provide substantially complete mixing of said annular stream and said hot gas stream within the central portion of said mixing zone;
  • auxiliary combustible employed is selected from the group consisting of carbon monoxide, hydrogen, methane, acetylene and liquefied petroleum gases.
  • auxiliary combustible is carbon monoxide
  • the titanium tetrachloride is pre-heated to a temperature of from 300 to 400 C. and wherein the molar ratio between said car bon monoxide and said titanium tetrachloride is at least 0.3 /1.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Carbon And Carbon Compounds (AREA)
US00054715A 1969-07-31 1970-07-14 Process for preparing titanium dioxide Expired - Lifetime US3735000A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT2036769 1969-07-31

Publications (1)

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US3735000A true US3735000A (en) 1973-05-22

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US00054715A Expired - Lifetime US3735000A (en) 1969-07-31 1970-07-14 Process for preparing titanium dioxide

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US (1) US3735000A (xx)
CH (1) CH527890A (xx)
DE (1) DE2037990A1 (xx)
FR (1) FR2053315B1 (xx)
GB (1) GB1286760A (xx)
NL (1) NL7011201A (xx)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4554078A (en) * 1984-05-21 1985-11-19 At&T Technologies, Inc. Methods of and apparatus for effluent disposal
US4803056A (en) * 1983-07-22 1989-02-07 Kerr-Mcgee Chemical Corporation System for increasing the capacity of a titanium dioxide producing process
EP0427878A1 (de) * 1989-11-13 1991-05-22 KRONOS TITAN-Gesellschaft mbH Verfahren und Vorrichtung zur Herstellung von Titandioxid
US6471937B1 (en) * 1998-09-04 2002-10-29 Praxair Technology, Inc. Hot gas reactor and process for using same
US20070292321A1 (en) * 2004-07-20 2007-12-20 Plischke Juergen K Apparatus for making metal oxide nanopowder
US20070292340A1 (en) * 2004-07-20 2007-12-20 Plischke Juergen K Process for making metal oxide nanoparticles
US20080152582A1 (en) * 2006-12-20 2008-06-26 Rainer Gruber Method for Manufacturing Titanium Dioxide by Oxidizing of Titanium Tetrachloride
US20080226510A1 (en) * 2005-10-10 2008-09-18 Ulrich Riebel Extensional Flow Layer Separating Reactor
CN113041986A (zh) * 2020-04-23 2021-06-29 东华工程科技股份有限公司 氯化法钛白氧化反应器

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE792503A (fr) * 1971-12-10 1973-06-08 Montedison Spa Procede de preparation d'un bioxyde de titane d'une taille de particules controlee

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE489882A (xx) * 1947-09-02
NL145503C (xx) * 1948-02-20
GB703504A (en) * 1951-07-09 1954-02-03 Schweizerhall Saeurefab Production of finely divided metal oxides
FR1383774A (fr) * 1962-07-17 1965-01-04 Thann Fab Prod Chem Procédé et appareil de production d'oxydes métalliques finement divisés par combustion d'un mélange de chlorure métallique et d'oxygène dans des gaz chauds provenant d'une flamme auxiliaire
FR1547126A (fr) * 1966-12-14 1968-11-22 Sir Soc Italiana Resine Spa Procédé et appareil pour la préparation d'oxydes métalliques

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4803056A (en) * 1983-07-22 1989-02-07 Kerr-Mcgee Chemical Corporation System for increasing the capacity of a titanium dioxide producing process
US4554078A (en) * 1984-05-21 1985-11-19 At&T Technologies, Inc. Methods of and apparatus for effluent disposal
EP0427878A1 (de) * 1989-11-13 1991-05-22 KRONOS TITAN-Gesellschaft mbH Verfahren und Vorrichtung zur Herstellung von Titandioxid
US5196181A (en) * 1989-11-13 1993-03-23 Kronos (Usa), Inc. Process for the production of titanium dioxide
US6471937B1 (en) * 1998-09-04 2002-10-29 Praxair Technology, Inc. Hot gas reactor and process for using same
US20070292340A1 (en) * 2004-07-20 2007-12-20 Plischke Juergen K Process for making metal oxide nanoparticles
US20070292321A1 (en) * 2004-07-20 2007-12-20 Plischke Juergen K Apparatus for making metal oxide nanopowder
US7465430B2 (en) 2004-07-20 2008-12-16 E. I. Du Pont De Nemours And Company Apparatus for making metal oxide nanopowder
US7708975B2 (en) 2004-07-20 2010-05-04 E.I. Du Pont De Nemours And Company Process for making metal oxide nanoparticles
US20080226510A1 (en) * 2005-10-10 2008-09-18 Ulrich Riebel Extensional Flow Layer Separating Reactor
US20080152582A1 (en) * 2006-12-20 2008-06-26 Rainer Gruber Method for Manufacturing Titanium Dioxide by Oxidizing of Titanium Tetrachloride
US7968077B2 (en) 2006-12-20 2011-06-28 Kronos International, Inc. Method for manufacturing titanium dioxide by oxidizing of titanium tetrachloride
CN113041986A (zh) * 2020-04-23 2021-06-29 东华工程科技股份有限公司 氯化法钛白氧化反应器
WO2021212405A1 (zh) * 2020-04-23 2021-10-28 东华工程科技股份有限公司 氯化法钛白氧化反应器
CN113041986B (zh) * 2020-04-23 2024-06-04 东华工程科技股份有限公司 氯化法钛白氧化反应器

Also Published As

Publication number Publication date
DE2037990A1 (de) 1971-03-18
NL7011201A (xx) 1971-02-02
CH527890A (it) 1972-09-15
FR2053315B1 (xx) 1974-05-24
GB1286760A (en) 1972-08-23
FR2053315A1 (xx) 1971-04-16

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