DE1592450A1 - Process for the production of titanium dioxide - Google Patents

Description

PATINTANWXLTE DR. E. WIEGAND DIPL-ING. W. NIEMANN 15 924S0 DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MDNCHEN HAMBURG

PHONE. 55 54 7Ä 8000 MÖNCHEN 15,

TELEGRAMS.KARPATENT NUSSBAUMSTRASSEIO

February 6, 1970 W. 12 829/66 13 / RS / Loe P 1592 450.2-41

Laporte Titanium limited London (England)

and

American Potash & Chemical Corporation Lob Angeles, California (V.St.A.)

Process for the production of titanium dioxide

The invention relates to a method of manufacture of titanium dioxide,

There is an ancestor in British patent specification 39 536/61 for the division of titanium dioxide duroh conversion of titanium tetra chloride with an oxidizing gas in the steam

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phase described ", with which one the titanium trachloride and heating the oxidizing gas to such an extent that when the titanium tetra chloride and the oxidizing gas would be mixed without reaction taking place, the temperature of the resulting mixture at least 700 ° C the preheated titanium tetrachloride steam and the preheated oxidizing gas in a reactor introduces through separate inlet devices in the path, that an eddy current of intimately mixed gases is generated, in which the titanium dioxide is formed in finely divided form becomes an inert particulate refractory material introduces into the reaction caramers in the ν ice that the Teilohenförnige material on the reactor surface or surfaces that are in the immediate vicinity of the gas inlet device and are accessible to both respondents are, - occurs to the deposition of titanium dioxide product to prevent or significantly reduce on this surface or these surfaces, the particulate Material at least in the weekly from the Roaktionskainmer is carried out in suspension in the gas eddy current, and then separates the particulate material from the titanium dioxide product * ■

According to the invention, a process for the production of titanium dioxide is durtih reaction of titanium tetra chloride with

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an oxidizing gas created in the vapor phase at which one is the titanium trachloride and daο oxidizing gas preheated separately in an indirect way to such temperatures, that the mixed gas temperature (i.e. the temperature which is the gaseous perforation within the Röaktionskaramer would achieve if there was no reaction between the titanium tetrachloride and the oxidizing gas would take place in the cooking, but not exclusively any between that oxidizing gas and any other substances that can be introduced into the reaction canimers »taking place Reaction) is at least 8oo ° C, the preheated oxidizing gas in an elongated reactor through a first Inlet device introduces, ν * don preheated titanium tetrachloride vapor is introduced into the reactor through a second inlet means which is downstream of the first inlet means is arranged, a combustible gas into the reactor upstream of the second inlet means with a such speed introduces to the mioch gas temperature by an amount within the range of 5 to 200 ° C raise"

Indirect preheating (i.e. preheating by VUr- ' meauetauBoh through a gas-impermeable medium, for example the viand one. Tube) of the oxidizing gas and the Titanium tetrachloride has the advantage that the introduction

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of other gases in the system is avoided} however the preheaters must be suitable for both high temperature and high temperatures also the attack by the reaction participants, in particular the titanium tetrachloride, can withstand. In the practical Execution, this means the Vorwondung, at least for the Ti tantetrachloridvorerh.it 2er, a line that consists of a non-metallic refractory material such as silicon dioxide, is made or lined with it and (as will be explained below) makes it difficult the precise and flexible regulation of the mixed gas temperature. The introduction of a low slope of a flammable gaoo allows the Jji-chgas temperature to be set precisely to any desired temperature within a high range, but without the introduction of a large one Volume of another gas in the system, which, for example, is the case when the entire preheating of the oxidizing Gas is carried out in a direct way, i.e. by burning a combustible gas and incorporating it of the hot combustion products with the oxidizing gas.

The reactants (including any inert components of the oxidizing gas) have advantageously been preheated to a temperature such that the Minch gas temperature is within the range of 0 [jo to }. loo ° 0, preferably within the range of 900 to lo50 ° C

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lies. The one for generating a given temperature (which is of course a calculated value), required Vorhoiztomporatur · not only depend on the Amount of combustible gas introduced into the reaction carafe from, but also from the mongen, temperatures and the species of other substances, for example the gas in which the inert particulate refractory material is suspended , that are introduced into the reactor, the introduction of cooling gas amounts, which are generally of a higher degree make it necessary to preheat the reaction participants,

except -.enn the cooling gas (or part of it) is exothermic Reacts with the oxidizing gas * Exceptionally hanging those required to generate a given million gas temperature Preheating temperatures depend on the Würia losses that between the 'preheaters' and the' areas of introduction the reactants occur in the reaction chamber.

The reactants can instead use a heater with a pebble heater. or V.'irbelsohiohtbettorhitzer (including Virbolschichtbotterhitzorn, in which an internal electric heater is provided lot, and vortex bed heaters in which Particles drawn from the Bott, heated from the outside and in the bed has been reintroduced) has been preheated.

as described in British Patent 23,047 / 63 indirect preheating of the raw material parts

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by looping through the relevant reaction participant by a heated pipe with such a formation, that at least a substantial part of the tension that develops in the pipe that results from thormatic stresses or stress reduction results in torsional stress is. Compared to using a tube i.iit such a training that in essence the entire thermal stress or thermal stress a bend results, according to the Veise described above, the relative occupancy of different parts of the pipe during of heating and cooling and accordingly the Carrying or supporting the tube3 makes it easier. Advantageously the pipe consists of a plurality of straight lines. Parts whose axes are essentially parallel to each other and which are separated from each other by parts that are at an angle (preferably essentially a right Angle), dried out to the straight parts, the arrangement one such is that the axes of the straight TeHe alternately in a given plane and outside it

* Level (preferably in a two-tone level, which eu of the advisory

• said plane can be parallel) lie «instead

■ ■ t '

, dfio tube can also be designed in the form of a helix. Except at its ends, the tube is advantageously only a tube supported or borne from below, i.e. during executions » the self © ine upward movement or a horizontal

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does not prevent the right movement of the pipe. That or each heated Pipe can be carried or supported on fire bricks.

Advantageously, "the" or the heated tube is supported by a plurality of support members which are formed from refractory material and attached to a metal structure cooled with a medium. The support members are advantageously made of silicon dioxide and are advantageously made in the form of bridges formed with semicylindrical cavities in which the tubes rest. The Kotall construction can be made of steel or a nickel alloy (Inconel) and can be tubular, the cooling being effected by passing a suitable coolant such as water through the pipeline. Preferably, the cooling extent of the metal structure is controlled so that the movement of the support members "which results from the expansion and contraction of the metal structure" is essentially the movement of the parts of the heated tube which are in contact with the support members, this movement being derived from the is obtained expansion and contraction of the heated tube, the same iet "XSm Y / äriue losses to a Hinimum result, the surfaces of the metal builds up can be protected duroh suitable refractory bricks or ähnliohe members or shielded, for example by firebricks. It

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It is of course important that the extension and the draw this Sharaol to 8th one the movements of the heated Rohrs and the supporting member are not influenced, and for the purpose of strengthening this purpose has been made, with no need for creating of large gaps between the stones on the one hand and the Support members and the orhitaten pipe on the other hand at least some of the stones or similar links appropriately to yours Metal structure attached · Some of the ones attached to the metal structure Its can between the metal structure and the support members be inserted, provided that the thickness of such inserted stones or similar links is not is so great that the expansion odor dna contraction of this inserted stones or similar limbs any essential Movement of the support members with reference to the metallic structure cause. Thus, the metal structure can have a plurality of substantially vertical support posts or supports include those with horizontally extending beams (which carry the stones or similar members and the support members) are formed and both the trough members and The stones or similar links can be provided with slots or openings to go around the door or post -support zupassön. If necessary, the strength The metal structure can be heightened by adding brackets, which to connect the support posts or supports (or some of them).

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For preheating doa titanium tetrachlorida can be heated Pipe made of a non-metallic refractory material, preferably of silicon dioxide, or a suitable one Metal, bnispielawoise platinum, a platinum alloy or a platinum-lined or praised nickel alloy (Inoonel) formed aein. For preheating, dot dxydierenaon Gaaeo, however, a metal pipe can be used, provided that the amount of preheating is not too high is (normally not above Io5o ° 0).

The preheating tube for each of the reactants is preferably heated by means of radiation. Thus, the heat can be supplied by a heater which burns carbon gas or butane and is arranged to heat a brickwork or masonry, the surface of the masonry radiating heat to the ear. Instead, an electric heater, for example of the silicon carbide resistor./tandsart, can be used, the arrangement being such that the tube is partially cut through. from the elektriaohen heater solbtit radiated ¹ Värme and toilweise by dom masonry, daο duroh the eloktrißchen heater orhitz 'v / ordon iat, abgeutmahlte V / is heated iirmo "Menn dao tube auo Motall is formed, a (5lerhit2er may have been used. In addition, if the pipe on noharaotteotoinon ßotru, -, on becomes, in addition to the rhythm by means of struhluhga-

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add some heat to the pipe by conduction from the masonry, dia is in contact with the pipe, supplied wonton. Instead of using a tubular preheater for the titanium tetrachloride, this reaction participant in that described in British Patent 3o 133/64 Way to be preheated. This patent describes a process for the production of titanium dioxide by reaction of titanium vitrachloride with an oxidizing gas in the vapor phase, including the titanium tetra chloride and the oxidizing gas Gas has been separately preheated to such an extent that,

before
If there was no co-action between the preheated reaction participants in the gaseous mixture within the reaction chamber, the temperature of the gaseous reaction would be at least 700 ° C, one of the preheated reaction participants introduced into a generally round or tubular empty reaction chamber through a first inlet device and the other preheated reactants are introduced into the reaction chambers through a second inlet device, the arrangement being such that a vortex flow of intimately mixed gases is generated which flows longitudinally of the chamber and in which the titanium dioxide is produced in finely divided form; In doing so, the titanium turret is in a hotall within a housing, then inside with a non-metallic, fireproof Γ: α-.

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material, which is inert with respect to titanium tetrachloride, lined is, located chamber is preheated, the heat supplied to the interior of the preheating chamber by means of a A large number of heating elements that have been heated from within, and protruding through the housing and outer lining will and the parts of each element that are associated with the titanium tetra chloride stand in contact, a ^ non-metallic refractory, with respect to the titanium tetra-chloride inorten material are formed.

The tetra chloride vapor can be liquid titanium tetrachloride be generated in a flash evaporator made of aluminum or a suitable aluminum alloy or a corrosion-resistant steel, for example a stainless steel, is made

The combustible gas that is introduced into the reactor can be selected from aoetylene, naphthalene, anthracene, methane, ftthane, butane, Consist of ethylene or propylene; preferably it consists of Carbon monoxide.

The extent or rate at weloher the combustible gas is introduced into the reactor, is expediently to the mixing gas temperature by an amount of not more than loo ° C, and preferably in order to increase a maximum amount of Sun ⁰ C * Venn the combustible gas consists of carbon monoxide, / ird it is preferably in the reactor at an elevated temperature, expediently from less than 300 ° C and preferably not above

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600 ° C introduced »

The combustible 6aa is usually intended to power the reactor at a Such a passage has been introduced that essentially dio total heat release as a result of the combustion of the combustible gas takes place in the area where the reaction participants are mix, and / or immediately stronaufwfirto from this Area. For example, in typical Gangei.; Chv. 'Indigkeit and mit. Carbon monoxide as Brennbäros'Gas these advantageously introduced into the reactor at a point axially from the titanium tetrachloride inlet in an abotand of at least about 4 inches (Io, 16 cm) or at least eng Inner diameter of the reactor immediately downstream from the titanium tetrachloride inlet (whichever is larger) introduced · Preferably this distance exceeds about

o, 6o "üryi> (Jler the lo times the inner diameter (depending on of what is smaller) not.

Venn (as described below) the inert toilchonförraige Refractory material is introduced through a nozzle placed coaxially inside the reactor, it becomes combustible Gas is advantageously introduced through pipes that extend parallel and in the vicinity of the nozzle and by no more than about 7 »6 oin (3 inches) upstream of the stror.iabwii.rtβ located End or if (as described below) distraction facilities are done inside the reactor, uirdohenfönaige material by a coaxially inside

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introduced the deflector, it being obviously important to make such an arrangement that the "poor" released by the combustion of the combustible gas

. the nozzle or deflector is not damaged or destroyed

A relatively small change in the gas temperature, for example 2o 0, has a bomerkens

- evaluate influence on the pi ^ mente properties of the produced Titanium dioxide and to the transition from the production of one

Degree _{u (J} g of titanium dioxide on another without interrupting the process, the gas temperature can be changed by changing the rate of introduction of the flammable gas. In addition, minor changes in the rate of introduction of the flammable gas can be made to compensate for fluctuations in the performance of the preheater and on These V'eiae the Mi ßohgastempera door to maintain essentially constant at the desired "value. Such small changes can automatically in response to eg" B "changes in the temperature of the product stream at a tunnel located far downstream from the titanium tetrachloride inlet, so that the Reaction is essentially complete, has been effected, whereby care must be taken to ensure the stability of the control system · In this way, a control device for the rate of supply of the combustible oasis can be provided.

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eehen, the control or regulating device being adjustable is to order for a given medium degree of preheating any of "a number" of different Gas temperatures, for example temperatures at intervals of lo ° C, and automatically small deviations of the degree of preheating of the above mean to compensate for the Miaohgasempe-

rature essentially on the desired l.'ert to haiton » An increasingly important property of white pigments, especially titanium dioxide pigment clay the carbonblaok undertone value, the is usually given as O.B.U.-iVert · The Ö.B.U .- 'ert becomes noticeable through small changes in the gas temperature influenced. If the other eligible factors To be kept constant »possesses the increase in the nif.'Chga8 temperature the effect of a humiliation of the C.B.U.-v.ortes.

The addition of a given amount of carbon black pigments au white paints, the same weight concentrations white titanium dioxide pigments with the same dry color, ijedooh of, various mean particle diameter, contain, leads to a bore of gray anutrails with different Color tones, with the gray tones ranging from blue-gray for small toilets to yellow-gray for large ones ToilohendurohmesBor vary «Anstrioha, those with colored or colored pigments are tinted are influenced in a similar way

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This. The effect results from the difference in the refractive index of titanium dioxide for blue and red light »the length of the path of blue light within a film of a titanium dioxide paint, which is less than the corresponding desire for red light is leads. This is a problem with white paintwork a slight effect {but with gray or colored paints, at which there is noticeable absorption of light, the difference in the lengths leads to different ones Degrees of absorption of different colors. The greater path length in the oncoming film of the red light makes it stronger is absorbed as the blue light, so that the reflection of the paint film for red light with respect to the reflection for Blue light is reduced

The size of the difference in the path lengths is a function of the mean partial ohmic diameter of the titanium dioxide pigment, the difference in the path lengths being greater than ^v for smaller particle diameters. For example, the use of a pigment with a small average particle diameter tends to intensify the blue tones

The O.B.U.values given here are values that are determined by Hesse of the reflectivity for red, blue and green light of samples which concern standard amounts of soot and dome Containing titanium dioxide pigment, with reference to a standard gray surface "The O.B.U" value is the undiscussed between the reflectivity for blue and red light, from

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depressed as a percentage of the reflection amount for green light.

The OB * U. -value of a given pigment depends of course on the particular reference surface selected, the wavelengths at which the reflectivity is determined, and on various other factors, for example on the special production method of the carbon black. therefore, a untorochiedliche ^v leads' ahl these different factors at different scales or Meßtafeln of CBU'erten, it has been found that the different scales for pral, -. For the purposes of the table, there is a good agreement within an additional constant or additive constant. Thus there is a good agreement between the difference in the CB values for two pigments when determining ^ on different scales. The OBTJ. Value of a given pigment or a given scale is usually reproducible within - a half + 0.5 unitsAll OBU values given here are measured on the same scale

If technically acceptable components are to be produced, the G.B.U »-Ytert must be given within + 1 unit of einoia Value to be regulated. Furthermore, since the influence to balance the tint or color of the Kediun in which the Pigment should be used, can be used Pigments with different O.B.U, -tone for veruohiedene Z'veoke requested and therefore should contribute to the creation a precise regulation of the C.B.TJ .- 'Ortea an ancestor for

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the production of pigment grade titanium dioxide preferably be flexible and resilient to change Oine deo CBU "- such erte3 the product> · allow" VIq explained vorstehond "v / ith the regulation and Flexibility achieved by the introduction of the combustible gas · '.'

The following is an example of the manner in which the effect or kin flow to compensate for the coloring of a Medium can be used, shown & In linoleum the pigment is incorporated into a yellow medium and through the "use." of a pigment with a high negative O.B.IT.-V'ert (which gives a shade of blue.) it is possible to achieve an end product with a neutral white appearance

Technical or commercially available pigments for use in paint materials generally have C.B.U.- ■ .v'erta within the range of -1 to -5 units, G.B.U. values towards the negative end of the range, i.e. from -5 to -5 units correspond to the particle size range that most effectively scatters light, and thus pigments of higher Opacity. Pigments with Ö.B.TJ. Values of -6 or lower are generally used in floor coverings and in paper and plastics preconditioned «For O.B.U. values below -5 or -6 occurs a progressive. Decrease in deck property on, there some of the pigment parts are too small to be effective To contribute to stowage dos Liohta in the visible range of the spectrum » - ■ "

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The surface of the part is advantageously dea
Reactor, which is present immediately downstream of the titanium tetrachlorido inlet, is frustoconical and extends in the upward direction, the angle of the cone or cone being within the range from 1 ° to 30 °, preferably within the range from 2 ° to 15 ° and the length of the
sloping portion ranging from 1 to 25 traversing the interior of the roaktor is immediately downstream of the titanium tube chlorido inlet. .

It has been found that the creation of such stuiapfkegeligen part and the angle dea cone a substantial Influence on the properties of the Pignenta, in particular to the (J.B.U .- ^ ert (whose meaning is explained above was) own.

It is assumed that the frustoconical part is a separation or detachment of the flow from the surface of the
R ^ action chamber and consequently a Rüclmiochon that brings about the reaction part. In other words, it is assumed that the truncated conical part serves as a flairuaon holder and tends to stabilize the reaction in that it causes the hot gases to be recirculated to the tank of the titanium tetra-orido inlet.

It is believed that two mechanisms take place in the formation of titanium dioxide. The first combination of moohaniamides involves a complete gas phase or homogeneous reaction. Dor aweit Hoohanisraus uiafaßi a heterogeneous reaction that

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surface of titanium dioxide nuclei or cores or other nuclei takes place and contributes to particle growth! The relative speeds of these reactions determine both the mean particle size and the distribution of the particle size of the product. that 'an appropriate Oberflächenbereieh of titanium dioxide in this area available "is this a distribution of particle size results in recovery in a Engon area and it may also be that the resulting air vortex virkt as raw or Grobkla.ssifizierungsmittel and thus also to obtain a narrow distribution range of particle sizes tends to

It has also been found that the creation of such a tapered portion leads to an increase in the proportion of Titanium dioxide product formed in the rutile form tends to be.

Preferably, an inert particulate., It refractory material of larger mean particle size than the titanium dioxide product is introduced into the reactor in suspension in a gas such that the particulate material hits the inner surfaces of the reactor in close proximity to the second inlet device Any possibility of depositing oxide products on the inner surface of the surface to be prevented or even sometimes horabcuootnen; dna particulate material is taken out of the reactor in suspension

- ■ - - - * ■ - t

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carried out essentially completely in the product gas stream and the particulate inert refractory material v; is then separated from the titanium oxide product.

The inert particulate fiery red material becomes Tooamrien with the carrier gas in which it is suspended, expediently into the reactor through a nozzle attached coaxially inside the reactor and directed in the direction of the downward flow shows, introduced. The nozzle can be made of a suitable corrosion-resistant. etall, for example a nickel alloy (Inconel or Ni-Hard) or made of a suitable corrosion-resistant and wear-resistant, non-metal! see material, for example Aluit: inäumoxyd, manufactured sel.n and can be surrounded by a coat if necessary through which a cooling medium can be passed. Wherein the wall of the reactor upstream of the titanium trichloride inlet is formed from a non-metallic refractory material, the nozzle can be attached to the wall by means of a Link of the type described in British Patent Specification 26 718/62, optionally (with some Arrangements), omitting the cooling ring.

The inert particle fÖnaiGe refractory material must be made from consist of a hard solid obtained by chlorine at dor temperature and the rest during the reaction Conditions are not significantly attacked; The iac-

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Cerial can be made from zirconium particles, aluminum oxide particles or titanium dioxide particles, for example from particles boot ehon, which are derived from a l used, can be withdrawn or the material can consist of grains of titanium dioxide produced in the manner described in Canadian patent 599 557, this patent specification employing a process of cooling the reaction product stream of titanium oxide and accompanying gases boachritten, which is obtained in the toroidal phase oxidation of TiCIh au TiOo; (() this ancestor, the current is conducted through an externally cooled conduit, whereby the titanium oxide adhering to the walls of the conduit is

grain
The amount of titanium dioxide in the stream is about 1 to 10 percent by weight, based on the weight of TiOo in dom Gtrom, the titanium oxide grains being removed by washing with water, saiuiviol and heat a T'.Tiiperatur within the range of 500 to 90O ⁰ C of Ti. '. andioxydstaub from a i'.tihle under Λην / ending a. Fluid onergy mill, which is used to grind dom TiO ₀ product, which was orüougt in oinor Dcnnpfphaaonoxidation von TiCIh,

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used on a pill toilet size the titanium dioxide escaping from the cooling line and the exiting gas-filled products are separated and that

wrirdi
Cooled Tltandio3; yd geitfonnert Advantageously, the material consists of silicon dioxide sand. The material can also consist of a mixture of more than one of these materials.

The particles should not be smaller than + 05 Wash (BSS), which corresponds to a tile diameter mosaic of Vf o ,, ik _A 'on and the practical upper limit is generally determined by the requirement that the special refractory material is made the Reaktioüükai.imQi should be carried out 'by' a gas stream. Practically all particles have pits within the range of - 10 to 3 + 40 hashes (BSS), v / as a range of milk diameters of about 400 to Γ / Ό0; ikron corresponds

The optimal extent of the filling rena of the inert Particulate refractory material hangs from the griffin and the dimensions or the shape of the reactor has been varied during the implementation of the procedure. If the speed is great, it is accordingly the food menu to be separated from the oxide product is large and, if (as described below) the iluterial in theonktlonskaminor at an au low temperature

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is introduced into the neaktlonokömmer, an unnecessary Cooling the Reakttonteilnohiaer and consequently a irreversible implementation occur »Therefore, the material be introduced at an elevated temperature.

The inert particulate refractory material should be introduced into the oxidizing gas supply line at a rate of at least about 6m / böc (20 feet per second) and preferably in the range of about 15 böjX) in / see (50 to 100 feet per second) will. The upper limit for the rate of introduction of the inert refractory particulate material is determined by the requirement "that the rate should not be so high as to cause excessive wear on the reactor surface or surfaces" To avoid excessive wear on the surfaces on which the inert particulate refractory material impacts, and if the material is introduced through a nozzle, to avoid excessive wear on the inner surface of the nozzle, et v / a 52.5 m / see (175 feet per second) and preferably about> 6 m / see (120 feet per second).

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The Trltgergas in the suspension in which the particulate .Material is introduced, may consist of an inert gas, i.e. a gas _# the teilnehnern to the reaction ^ · is inert under the reaction conditions, for example, chlorine or nitrogen "Of the inert gases is Chlorine is generally preferred because it does not lower the concentration of chlorine in the product gas stream, the chlorine being recycled back into the cycle and used for the production of further titanium trachloride.

In particular, the carrier gas advantageously exists from an oxidizing gas, preferably oxygen, if a small reaction chamber (i.e. a reaction chamber with a diameter not exceeding about 10.16 cm (4 inches) is used. The concentration of the particulate refractory material in its * Trögergas should be high, namely within dos DoiOichs of about 0.045 to 0.45 kg (0.1 to 1.0 poundj ί-aterial 23 each, ρ 1 (per cubicfoot) gas (measured on the pressure of the introduction of the Gas in the reaction chamber).

The titanium dioxide product can be of the inortic particulate form Refractory material separated by means of settling chambers will; however, cyclones can also be used instead of or subsequently to the settling canisters. Uonn, Kio this is usually the pail, the titanium dioxide product -Nai3abtronnui ¥ P- and Klao3lfiaierungsgrades

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is subjected, the titanium dioxide can be of the inert particulate refractory material can be separated during these steps. After separating from the Titanium dioxide product and, if necessary, after drying, the inert particulate refractory material becomes expediently returned to the reactor in the circuit «·

E3 is essential that the design or dimension of the reactor, the temperatures and the flow rate the reaction participants are such that the R ^ action- tellnehinor and the reaction products within the oxidation zone for a long enough time to ensure a substantially complete reaction. However, not so long to prevent unwanted particle growth of the oxide products. Usually turned out Impact sides within the range of 0.02 to 10 seconds as suitable.

Wherever the oxidizing gas consists of pure oxygen or of aa ^ QratottanQ & eiohQvtQV air, the Vorwoilaoit can, under suitable conditions, be as low as 0.01 seconds.

If the gaseous products that contain the Oxydprodukt In suspension Oxydati onsiione leave be aio awecktriäiJig cooled rapidly to a temperature below 900 ⁰ C (before ^ ugawoiso below 650 ⁰ C). The KUhlon

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the reaction products can UEU a time innpriialb of Beröiohß of O _# Ojl to IO see executed (vorsugswoiso 0.05 to 5 lake) from the iioit dor Cnlorideinführung in the Oxydationazone to been · Cooling may be by Irish of cooled product gas, for example chlorine, with do ^r n ΛΆ3 oxide product in suspension containing product gas stream are effected. In another way of cooling, the products are passed into water, as described in British patent specification 3b 702/65.

The separation of the titanium dioxide product from the inert particulate refractory material and the cooling of the reaction products can be carried out in a single operation in the manner described in British Patent 5,909/64; This patent describes a process for treating a chlorine-containing suspension of pigmentary titanium oxide and an inert, particulate refractory material with a particle size not larger than that of the pißmentartisson titanium oxide, the suspension being introduced into a vessel in which the gas velocity is too low to be heat the plgiaontnrtige titanium dioxide and the inert particulate formo riaterlal, so that a bed of particulate matter is formed within dos Gefälics, an inert gas is passed up through the bed of particulate formo il of the inert gas and the inner Godalt and discharge of the

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So that the bed consists of a first layer mainly your inert particulate material consists, of which at least the upper part is not present in a fluidized bed, the first layer of one two-tone layer of mainly your pigraent-like Titanium dioxide is superimposed, which is in vortex state in dense Phaoo, and from the two layers the toilet-shaped material is removed separately

The oxidizing gas preferably comprises molecular ones Oxygen and can be made from practically roinom oxygen or from oxygen in premix with an inert gas or inert gases exist, for example the oxidizing gas can consist of air or oxygen-enriched air. An effect of using -air or oxygenated Air instead of practically pure oxygen as an additive gas tends to produce of titanium dioxide with a, smaller particle size * The choice of the oxidizing gas depends to some extent on the diameter of the Reakttonskaramer. More to consider coming factors are the temperatures to which the Reactant preheats bind, the temperature which the surface of the Reakttonskananer is cooled, and the supply speeds of the rebate participants. The proportion of oxygen in the oxidizing gas is one dor factors, which Tdio of the gaseous mixture in the reaction zone reached the axiraal temperature, the temperature

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distribution in the longitudinal direction of the reaction zone and the particle size of titanium dioxide products, with an increase the proportion of oxygen leads to an increase in the naxiraal temperature is small, i.e. below about Io, 16 era (4 inches) beotoht the There is a risk that the reaction will extinguish prematurely if the oxidizing gas is air, and it is then necessary to use an oxidizing gas Gas with a higher proportion of oxygen, e.g. oxygen-enriched air or practically pure oxygen use »The danger of premature extinction of the reaction is greater if the ^ temperature to which the surface the reaction chamber is cooled, but this is deeper Paktor, usually less important than the grotto of the reaction chimneys and the feed rates of the operators. The risk of extinction of the reaction can be reduced, by informing the reactants about the preheating temperatures increases, but with the use of very high levels of heating leads to technical difficulties *

In the case of a reaction quay, this is always of greater magnitude Ratio of the volume of the reaction chamber to the area the inner surface that is cooled is larger and there is therefore the use of air as an oxidizing gas without the There is a risk that the reaction will extinguish prematurely.

The exhaustion or the speed of the introduction of deodorant

109828/1381

-29- 1592 * 50

oxidizing gas in the reaction chamber for the implementation \\\ The titanium tetrachloride can be used within the £ 3 range of So up to 125 / yr for the stöohiometriache implementation with your Titanium tetrachloride to the required extent. Are, however, preferably greater than this extent and in a two-minute manner at least 5? " greater than that dimension and preceded by a stepping out That amount no more than $ 15. Except for the implementation The amount of oxidizing gas introduced with the titanium tetrachloride is also required to be sufficient Conge of oxidizing gas for the stoichiometric conversion riit the combustible gas and with any additives that (as described here) in the Heaktionskar.uner can be introduced. Bio introduction of such additional amount of oxidizing gas despite the fact that the extent, as described above, is above that for the atöohioraotriscbe reaction with the chloride required Extent is necessary. When determining sines geoignotnn Introduction of the oxidizing gas must be carried out as soon as possible the introductory hallway of the pre-fused oxidizing London Gns as well as any oxidizing gas, dno in the reaction okawraor as triiger gas for the inert toilet hair dryer, fouerfob fco Ilatorial is included.

Z ^ / ^ cla / ulartig is in the Roaktionskarnner Wanoordampf in "inor Ilongo within the Boroioho of o, oooo5 bLo o, o25 parts o, ooo5 to ο, οοί? Great) 1 part each of TLtnntotra-

109828/138 1 BADORiGiNAL

Chloride vapor introduced into the reaction chamber (aind dio parts by weight boaogon) · The V.'aaoordampf is vorjiugaw se stirred into the reaction chamber in mixing with the oxidizing G '.'. s. Venn the oxidizing Gao / is atmooph irioche air, it can be found that the air contains sufficient moisture so that no additional V / has been anaerdampf added. Fromn the air is washed out to remove gaseous impurities, this can be done in the way that the amount of water vapor contained in the air remains unchanged, or that the amount of Vaoserdanrpf in the air is increased. The Y.aaserdampf can in Iri: -Chung with a Ga in the suspension in which dao inert particulate pimply, ^s / is introduced Jaer refractory material in the Reaktionska be introduced. A part or the gooamte water vapor ksirin has been formed by the burning of the combustible gas. The Congo steam introduced into the reaction chambers is one of the factors influencing the GBli.V / ert dco litandioxydprodukts.

Veraohiedene conditioning agents and andoro I-ittol are boldly introduced into the reaction bucket. Go can u.5. Muminiuinoxyd formed in the Reaktionskarainer and titanium dioxide for the formation of rutile Unturotütaung incorporated upstream ULOiI ₁ to other pigments igtmuchaf ton (aB means go ge n Gr) IbwoE-to improve in OfenUboratigon) and the Vlgmoiit eino neutral reaction after removal of gooignotor CJlilor or

109828, / "138 1

Ohlorid (beiepielswoiao by degassing at a temperature of 600 θ) has been ortoilt. The amount of aluminum oxide can be within the range from _{0 t} 2 "to Io >> 0? ■> and advantageously

oiao from 0.5 to 4 »o? * _t based on the weight of the titanium dioxide product. The aluminum chloride vapor can be dissolved by "introducing aluminum chloride into the roaktionsökaioiaer ₀ oMldet". The aluminum chloride vapor can be introduced into the roaktionskai'ir.icr in connection with the titontotracliloriddaiapf or through a separate line into the oil inlet device Gas is fed into the reaction chamber

'Vort eilhaft: is vorerhitat Johr, the AluminiuachloriddGiäpTyileia titanium tetrachloride vapor incorporated "indoia one is the Aluminiuiachloriddarapf in the heated" pipe oinführt · Anderorsoite kaui AluuiiniuKichlorid In the liquid Titantotrachloriä Before the Verdanpfung available leg · The Aluciiniunioxyd can also be formed \ /' lems, by? one aluminum metal powder the inert teilchenfönnigeni refractory material incorporated _v wherein the pulvorige Aluuiniuraiaotall is eingebrncht in Ruapenolon in don litantotriohloriddarapf. . .

In addition, Siliciuntotraohlorid in the Seaktionakawiner In an Ilenge (boroohnet öIb SiOg) within dea Itovon o _f o5 bio l, o Öew » ^f /», vorawoiso o, l to o _t 5 Gew ·: '», oingobraeht on the weight doö Titandioxydjroduktei

109828/1381

will. The introduction of silicon tetrachloride causes in the * titanium dioxide product has a tendency to have a smaller particle size The silicon tetrachloride can be poured into the reaction chamber be introduced through a separate inlet means or it can be introduced into a conduit through w-which the oxidizing gas is supplied to the reaction canister, however, it is preferably premixed into the reaction mixture brought in with dom titanium tetrachloride vapor. Titanium oxychloride * finely divided oxide »organic compounds (e.g. hydrocarbons) and titanium esters» which are used as material for dia Nucleation or nucleation act, or such an ilatorial result can also be introduced into the reactionokamiaer will. An embodiment of one in communication with the Invention constructed device for the production of pigment-like titanium dioxide by the vapor phase oxidation of Titanium tetrachloride suitable according to the invention will be described below for example explained in more detail with reference to the drawing.

Pig. 1 shows an axial view through the device and

Pig. Fig. 2 shows an axial sectional view of a modified nozzle suitable for use in the apparatus shown in JPig · 1.

According to FIG. 1, the device consists of a frustoconical reaction ocaramer 1 and a cylindrical feed line 2 for the preheated oxidizing gas urafas-

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send reactor. Line 2 is with the Roaktionskamer coaxial and for the supply of oxidizing gas to the open narrower end of the reaction tank 1 arranged.

Dan downstream end of the supply line 2 iot of the upstream or the narrower end of the Kealctionskaniraor 1 separated by a distance, nu form a in a peripheral direction extending inlet 3, which gives a \ communication between the reaction Kaminer 1 and an annular Vertoilungakanimer 4 and the an inlet for the pre-! heated titanium tetrachloride steam. ;

The one directly downstream from the inlet 3 Part of the Roaktionskainmor 1 is made by a stuapfkegoligen tubular member 5 limited at its upstream located end lait an outwardly extending flange. · The innermost part 6-of the flange is frustoconical and tapers in the downward direction of the Stroia, and the fiulsorate part? lot circular. A cylindrical cooling jacket 0 surrounds the member 5 * An inlet pipe 9 enables the supply of cooling water to an inlet formed in the cooling jacket 0 in the vicinity of its downstream end and an outlet pipe Io allows the withdrawal of Vassor through οinen into the Cooling jacket 8 formed outlet.

The feed line 2 eats from a cylindrical tubular tube Link formed, then generally through the reference watch 11 stated iot. The downstream end portion 12 of the

109828/1381

Öliedeo 11 has a double wall to allow the cooling of the cable 12 with oil or liquid, with inlet and outlet pipes 13 and 14 for the liquid coolant being provided in large part of the upstream end of the part 12. The downstream end face 15a of the limb 11, which forms the upstream surface of the inlet 3, is inclined in the downstream direction to the axis of the reaction chamber 1. The downstream surface 15b of the inlet 3 is formed from the upstream surface of the inner part of the flange 6 , which is integral with the member 5, and the surface 15b is inclined at the top in the downstream direction relative to the axis of the coaction chamber 1. The direction in which the downstream face 15b of the Tvinlaases 3 extends is necessary that the angle! between this direction and the perpendicular ₂ u of the axis of the Reaktfanskairjacr 1 smaller than the ontGprochende V / angle for the upstream curses 15a dee Sinlasaea 3, so t'.ass dia V.'oite of the inlet 3 ßo _t ; ön the Achao the Heaktionakaimer abniinrat.

At a short distance downstream from the inlet and outlet pipe 13 and 14 is the member 11 with an oich formed oratrockonden ring-shaped planach 16 to the outside, on which a circular flange 17 is located on the atroma upstream End of Ktihlinantols 8 by means of bolts (not ^ oiioi ^ t) is attached to the downstream liGijenden Enclo iot of the K'Jil-

109828/1381

jacket 8 to the annular member 5 by another Rin-tförsiigen Splash 18 "attached. A tubular link (17), the coaxial with the rohrförraigon member 11 iat and whole piece rait the outer toilet 7 of the Planoches on öt'Oiinufwärts Solegonen end of the tubular member 5. Is formed, has ßinon upstream end portion of reduced Diameter, uia to result in a tight fit over the part 12 of the gliod 11. At its upstream end the member 19 is attached to the flange 17. Link 19 and dor cooling jacket 8 are each in a cylindrical Expansion developed »which together result in a Ki.'hlloitung 2o, around the supply of preheated titanium tetra-chloride vapor au the ring-shaped distribution to enable akaiiimor 4

The upstream end portion of the gliod 11 is unobstructed by a tubular cylindrical member 24 which is coaxial with member 11 and at its downstream end with an inwardly extending annular Flange 25 is formed and at its upstream end with a sioh inwardly extending annular Flange 26 is provided. At the edge of his innon is that flange 25 attached to link 11 · Her Plansch 26 is on its inner edge to a short tubular member 27 of the same internal and external diameter as the member 11, the mounted coaxially with member 11 »bofontigt, that downstream lying end of the link 27 is through a subscription

BAD ORlGINAL

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from the end lying upstream the link 11 to form a lchlitr.oa & ϊ r; etrenn-t · The shiita 28 creates a connection with an annular Voröilungfikammor 29, which extends through the tubular limbs 11, 24 and 27 and the plansche 25 and 26 are delimited · The limb. 24 is formed with a cylindrical aundohnun, or extension Jo, which serves as an inlet for the preheated oxidizing gas »

At its upstream end it is tubular Link 27 with an outwardly extending rins-

förraigen splash 31 is formed, which by means of Bols'in (niclit shown) is attached to a circular plate 32 which is coaxial is arranged with the tubular member 27 "

The plate 32 is provided with a round opening which is coaxial with dom Gliod 11, through which a pipe 33 passes. allows the introduction of an inert particulate refractory Haterials in dan reactor. To enable the combustible gas to be introduced into the supply line for the oxidizing gas, two or more Rphro 34 are provided, the downstream end of which extend parallel to and in the vicinity of the pipe 33 and a short distance upstream from the downstream end of the tube 33 ends.

10 9 8 2 8/1381 ^Ofu <* 'Nai

The pipes 3 ^ extend aioh through openings in the plate 32 and run upstream from the plate and away from the pipe 33 in order to tie themselves with a pipe distributor to which the daa brerinbaro Gaπ can be guided through a supply line 36.

The ',' oito of the opening dea Flinla ^ aoa 3 may concern about 1, oil cn (0.4 inch); the direction in which the otrouauf- • * Ürta lying surface ll; a of the liinlaaBeo 3 üic: h oratrecks, can be at an "'incol of 30 ° to do ^ perpendicular to the axis of the Iifaktionöka: .if.ier 1 gonoiot ₄ be and the direction in which the atrouabwärtsa lio ^ iide surface liib do3 ^ inla.Ona

can unt- .T an angle of 23 ° to the perpendicular to the axis of the Rcaktionaka: j.ier 1 ^ onoi ^ t aoin. The V.'inlcel doa ina ^ in ^f iron Konua, on which the Innon surface "doo otuni-fkogolitien member 5 lies, can loo oein. The length of the gliodeo 11 can equal the lo-fold * dos Inn'ndurohr.ieonors offered . ".- 1 ^ on,

The device can auo a Nickolle & iorun & jbeiapiels- / oioo from inoonol, built up ooin.

In drive v. Then preheated to oxidizing Gno leads the class 3o au ^ 'o, v / o up 00 oich through dio rin, fünii ^ o V i-Loilun ^ f-ka! J; ior 29 and the öchllta 20 in dio Feed line for dc'ui ojcydiorondo Gaa ν iLt ^ rbowogt * Ιΐ.ι V .rlouf doo Durohtj - '. Ri {ja ho run b- r zu. dor Zu fahr 1 · L bung 2 v ^ r -'- cln / indon ir _t ; ondwoloho atark '.' n Uiuo _w oIi, i iigkoiton in don ii'.ro'uimgorduut '.' r doa

10 9 8 2 8/1381 ^{BAD 0R! GiNAL}

1592A50

oxidizing gasea and it forms a fentor or komr.antor stream before the oxidizing gas meets the invitation 3. This means that, apart from slight countercurrents to yornaohlü & sigonden or "eddy" (the .in "irbelw'rroribe-r conditions are unavoidably present) the oxidizing gas from linka to the right, as inclined in Fig. 1, over the gee: -? With the cross-sectional area of the supply line flowing directly down to the left side of the inlet 3 , and it can be ensured without further ado whether this result is possibly with a special design or a special construction of the device and with special Ga.strrJj.unür- ^ ech ^ indigkeit is achieved in which the 'flow need-'r of liquids in models with two degrees of weight ^:! hlton I-aJSf.tnb observed and investigated.

Causes the introduction of a combustible gas by die'Ziufuhr-loitung 36 in dio supply line 2 for the oxidative Gau an additional \ "uru & £ travel Taung uniuittolbar before the oxidizing gas hits the titanium tetrachloride vapor '. Thereby, the Ilischgaatemperatur is increased and, vio Hinr orlut ^ ili v.urdo, accurate control and ^behaves: lltnisr, VISSIG ra.-cho change dor jMiHohgantemperatur ornöglicht "

The previously obtained Titanium Coiloriddanpf'-is fed through the il.o line 2o, whereupon it is fed through the rLn. föri.iigo Vi> rtoiluu (jskar _t mer 4 and the inlet 3 zuuEintritt injd-ie.'et; i - tioii {jka jv> r 1 sioh moved, in which he »ioh υLt dni.i vorurhi tr, htm

109828/1381

oxidizing gas arises and forms fine-particle titanium dioxide uusetat, whereby "chlorine is formed when oxygen is used as the oxidizing gas. The istunpfkogeligo form lies in part of the reaction chamber, which is present immediately atromabuurto from the inlet 3, improves the temperature the reaction participant and causes a part of the reaction products to be returned to the level of the quantity 3

An inert, particle-shaped, feuorf ^ oteo llatoria'l, z, B, giliciuiiidioxydsand, which is suspended in a carrier gas, for example an oxidizing gas, is attached to the pipe 33

supplied with the TrUgorgas under pressure · This leads to a spray jet dee aue dnia end of the Rohroö 33 emerging particulateeix Kateriala, which on di8 surfaces the reaction chamber 1 and the feed line 2 in Close to inlet 3, which causes the formation of titanium dioxide deposits on the surface doi * Uoaktionakamiaor 1 will voruieden «

The circulation of a suitable coolant, inabosondero a coolant, e.g. water, through the cooling dumbbell B, serves to prevent impermissible corrosion of the Ι, ο-valley surfaces, which are excluded from the reaction participants or reaction products, as well as to prevent their formation of hard deposits of titanium dioxide product.

After leaving the reaction chamber 1 ', the Troduktgaustrotü smoke cooled and the titanium dioxide product is made from the

109828/1381 ^eAD original

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- 4ο -

Suspension removed and from the inert particulate .Material separated.

In the in piss. 1 shown embodiment for the device serves the stroiaabwirts lying] 3nd part of the tube 33 as a cylindrical dil3e for the. gaseous 3us enaion of dom inorten particulate material, which is introduced through the tube 33, instead of introducing the inert particulate, fjuerfoaten liaterials through such a D "so, which is mounted coaxially within the supply line for the oxidizing gas and for spraying the particulate Material is arranged directly on the flat surface in the vicinity of the inlet 3, the toilet-shaped terminal can be introduced into the supply line 2 in the line of the upstream end of the line, for example through 2 disks arranged at a distance from the axis of the line, and a deflecting means in stroiaab ^ ürta lying x'oil this supply line provided Siiin. such an arrangement is shown in Fig. 2. in the in Fig. 2 dargestellton arrangement ni :: jat the Ablenkungoeinrichtung the Forra Glieuoö a _t the allgomein by daa Bozugsseichen 37 denotes iüt. The upstream part 30 of Gliodoo 37 is Cylindrical, however, the downstream end part 39 of the limb 355 doesn’t increase in diameter and then decrease in diameter, specifically in the downward direction of the flow. On this V.'eiae v. The preheated to oxidizing Gau, the inert toilohenfön.iigo Ia-

109828/138 1

torial and any trough gas, which flow into the Gliod 11, bounded by an annular boron, which is adjacent to the inner surface of the limb 11 and whose front side also decreases and then increases again in order to achieve an effect similar to that of a Venturi Rohrs au ergobon. If desired, the member can ÖIN 37 is formed with a bore raittleren 4-0, either as a ^l:; inlai3 can serve i'iir the Brennütoffgaa or as a nozzle for the introduction of v / eitoreai tollchenfö stomach I-laterial.

The determination is made below using an example in more detail orla-rt, in v.'olohei.'i the parts and proaent indications Weight are weighed,

example

Titanium dioxide became through the vapor phase oxidation of Titanium trachloride under Varweiiflun, ;; a '^ r device, vio sio in the weekly in Pig · 1 of the drawing roped 1st, or-2GUijt. The device i / ar made of nickel alloy hergeotelit and the angle of the iriaginary cone, on w lchcm the inner neck Truncated cone Glindes lie ^ t, bo carried 4 ° 3o '.

DLo obronaufwärtsn liogondo Pläcno 15a dos an TJnCang he «dry out ßinlaoaeo 3 orobrückte never in a downward direction go . dlonor AcA Of>, Dio sbr.'or.iab ^. ' ^: rtnliogöndo 3 ¹ IUChO 115b dna in TJwfan ;; nrichtung itself or-

109828/138 1 ^BAD ORIGINAL

1 592A5Q

St 'eckenden inlet 3 extended in a vertical seal to the axis of the reaction chamber 1. The opening width dos inlet 3 was about 1.4 inches.

Titanium tetrachloride containing dissolved aluminum chloride was evaporated in a heated steam kettle and the resulting titanium tetrachloride vapor was 1.63 '. Aluminum chloride was preheated to a temperature of 95 ° G in a quara preheater and then fed to the pipe with a constant amount of 75 parts of titarite chloride per hour, the average speed of the gaoniochun ^ over the area of the opening of the inlet 3 was about 52 _f 5 m, jo! Second (175 feet per second). Dor pressure drop nbor

the allowance 3 was calculated and was equivalent to etiva 127 cn 'asoer ( ¹ Jo inches of water)

Oxygen was at a Krhitaer auo οinen Niokellcgierungiirohr preheated and the Einlaii 3o at a / a could tanten Auaiia.5 of 13 _f 61 parts of oxygen per Jtunde ru ^ eführt, • vüboi deMSnuer.'itoffatron before Eintroton in the rhitsor Before ^ V.asaor in an AuoaiaiJ of o, 32 parts' auuor jo .'- tundo ab-LJCUGUBen was »

Dor voro.rhitato S.uierotoff \ mrde den !! ohr 33 untor ^T ) ruclc and with an auoiaaü of 1 toil oxygen jo "fcunde nu ^ oiührb, what a Toilchondurchiaesnürbof '.' I of about Ouo Hikro bi.H about 17oo microns out tpriclit. Erhitaor iJiliclui.idioxy uoand uinor greetings ontnproohand an r> iob with oLn r clear

10 9 8 2 8/1381

159245Q

Mesh sizes from approximately 1700 "to 833 microns (mesh sizes -10 to +20 (B.S.S ·)) vmrde into the reactor through the pipe 33 with introduced at a rate of 7.5 parts per hour

The mean velocity of oxygen over it Area of the downstream end of the supply line 2-h was about 53.8 m; per second (196 feet per see.) ·.

Preheated carbon dioxide is fed from tube 36 in an amount of 1.24 parts per hour. The GeBjjatmenge of oxygen, which was introduced into the reactor was sufficient to yield complete combustion of the K-ohlonmonoxyds wherein such iflsnge ^ eurüekblieb _n residual oxygen, by about a surplus of 10 i "to the to stöchioraetrischen reaction with to give the titanium tetrachloride required amount.

However, the Misohgastemperatur would have been 810 ⁰ G, but by the combustion of carbon monoxide custody increased this to 93O ° E before the introduction of carbon monoxide.

Water was supplied to the inlet 9 2UR cooling of the inner surface of the frustoconical member 5 and the β Innenoberflriche de member 19 and the inlet 13 for cooling the Innenoberflftohe dee downstream Endtoils 12 of the tubular member 11, respectively.

109828/1381

Calculations based on measurements of the flow velocity of the cooling water and its temperature increase "BCIM passing through the device indicated that the temperature of the inner surface of the member 5 was about 33O ⁰ C.

The titanium dioxide produced was from the gaseous Reaction products and the Silieiuiadioxydsand under Using a device generally similar to that described in Pig. 3 of British Patent 3909/64 shown was similar and essentially following the operation described in the example of the specification. "■

A sample of the titanium dioxide produced was examined and found to be. excellent pigment properties and had a C.B.U. Y / ert of -4.3 and was entirely in the rutib form.

The rate of addition of carbon monoxide to the reaction vessel was set to 1.12 parts per hour reduced with a corresponding reduction in the oxygen supply of 0.07 parts per hour. This set the average oxygen velocity above the area of the downstream end of supply line 2 to about 59.17 m per second (194 feet / seo) down.

The bereohnete reduction in the contribution of carbon monoxide in the mixed gas temperature was such that the mixed gas temperature decreased 1O ⁰ C to 920 ⁰ C.

109828/1381 ^ _oaialNAL

became. A sample of the product was taken after the system had equalized, i.e. as the Temperature of the Y / water discharged from the cooling jackets indicated that thermal equilibrium had been reached, 10 minutes after the lowering of the. Feed rate of carbon monoxide the Case was.

The titanium dioxide produced was found to have excellent pigment properties, one C.3.U. value of -3.2 and completely in the rutile form.

In a comparative experiment the mixed gas temperature of 93O ^u O at 92o ⁰ C by reducing the became "preheating temperature of the titanium tetrachloride vapor is reduced and the. Thermal equilibrium was only after the expiration of" 1 hour and 20 minutes after the setting of the Y / feed arms in the Titanium tetrachloride preheater reached.

BAD ORIGINAL 109828/1 381

Claims (1)

Claims 1. A process for the production of titanium dioxide, wherein titanium tetrachloride is reacted with an oxidizing gas in the vapor phase, the titanium triochloride and the oxidizing gas are separated and indirectly preheated to such temperatures that the Misohgaetemperatur is at least 800 ⁰ C, the preheated oxidizing gas in a elongated reaction vessel through the first inlet devices and the preheated titanium tetra-chloride vapor is introduced into the reaction vessel through second inlet devices, which are located downstream of the first inlet devices, characterized in that a combustion area gas such as acetylene, naphthalene, ethane, butylene, methane, Propylene or preferred 109828/1 38 1 Notio subjects lArt / ä ι au * -j νγ. ι s. «uji« An * ™ ** «, w.» · Carbon monoxide in the reaction tank upstream from the second inlet device in such quantity is introduced that the temperature of the mixed gas by an amount in the range of 5 ° C to 200 ° C increases. 2. The method according to claim 1, characterized in that carbon monoxide is used as the combustible gas and the carbon monoxide is introduced at a temperature of at least 300 ° C. 5. The method according to claim 2, characterized in that the carbon monoxide is introduced at a temperature not exceeding 600 ° C. 4-, method according to claim 2 or 3 t characterized in that that the carbon monoxide is introduced into the reaction vessel at a point in the axial direction of the titanium tetrachloride inlet by a distance of at least the greater of 10 cm (4 inches) or the inside diameter of the reaction vessel immediately downstream from the titanium tetrachloride inlet is removed. * 5. Method according to claim 4, characterized in that the subscription between the discharge point of the coal 109828/138 1 ^ _{0 0R: GiMAL} ' nonoxydos and thorn titanium tetrachloride inlet a fourth 60 cm or ten times the inner diameter, whichever is lower, does not exceed « 6, method according to claim 1 to 5, characterized in that that the combustible gas is introduced in such an amount that the mixed gas temperature by an amount that Does not exceed 100 ° C. 7t method according to claim 6, characterized in that the combustible gas is introduced in such an amount that the mixed gas temperature is reduced by an amount equal to 50 ° 0 does not exceed, is increased 109828/1381