US2792077A

US2792077A - Recovery of titanium tetrachloride

Info

Publication number: US2792077A
Application number: US559993A
Authority: US
Inventors: Robert J Mas; Andre L Michaud
Original assignee: Thann Fab Prod Chem
Current assignee: Fabriques de Produits Chimiques de Thann et de Mulhouse
Priority date: 1956-01-18
Filing date: 1956-01-18
Publication date: 1957-05-14
Anticipated expiration: 1974-05-14

Description

May 14, 1957 R. J. MAS E-rAx.

RECOVERY OF TITANIUM TETRACHLORIDE 2 Sheets-Sheet l Filed Jan. 18, 1956 May 14, 1957 f R. J. MAS ETAL. 2,792,077

RECOVERY OF TITANIUM TETRACHLORIDE Filed Jan. 18, 1956 2 Sheets-Sheet 2 Gas 5/ Tic|4vapor TiCl4 Liquid Gos +o Tic g vapor B Y fame,

United States Patent O RECOVERY OF TITANIUM TETRACHLORIDE Robert J. Mas, Thann, and Andre L. Michaud, Vieux- Thann, France, assignors to Fabriques de Produits Chimiques de Thann et de Mulhouse, 'hann, France, a corporation of France Application January 18, 1956, Serial No. 559,993 14 Claims. (Cl. 18S-120) The present invention relates to an improved process for separating normally solid components from titanium tetrachloride contained in hot chlorination gases produced by the chlorination of oxidic titaniferous materials.

As is known, titanium tetrachloride is obtained by the action of chlorine on oxidic titaniferous ma-terials at'high temperatures in the presence of reducing agents. Rutile, ilmenite, synthetically obtained concentrates, such as titaniferous oxidic slags, etc. may be used as raw materials. The hot or crude gases coming from the chlorinator, in addition to gaseous vapors of TiCl4, contain normally gaseous materials, such as CO, CO2, Cla, possibly nitrogen and volatilized normally solid metal chlorides, such as ferrie, possibly ferrous chlorides, and aluminum chloride. The vaporized metal chlorides may also include SiCla. and chlorides of vanadium, zirconium, etc.

The separation of the technical grade titanium tetrachloride from -the mixture essentially free of undissolved solids is a diicult task due to the formation of deposits on the walls of condensers, on pipes, on heat exchangers and other parts of the apparatus with a consequent clogging or blockage of the apparatus. These deposits are made up principally of normally solid metal chlorides which are only slightly soluble or insoluble in titanium tetrachloride such as, more particularly, ferrie chloride and aluminum chloride. The deposits may contain also the dust contained in the gases formed in the chlorinator which flow therefrom at a fairly rapid rate.

Due to the difficulties involved, a number of processes for recovering the titanium tetrachloride obtained by the chlorination of oxidic titaniferous materials have been suggested. For the most part the suggested processes are of two types, namely:

(a) The chlorination gases are sprayed or scrubbed with cold titanium tetrachloride in such quantity that the larger part or substantially all of the titanium tetrachloride contained inthe gases is condensed together with the normally solid chloride with a subsequent separation of the titanium tetrachloride, for instance, by distillation.

(b) The chlorination gases are sprinkled or bathed with titanium tetrachloride in such a small quantity that all or substantially all of the titanium tetrachloride present is removed in gaseous form. Thus the condensed solid chlorides are separated either in the dry state or as a slurry containing a small proportion of liquid titanium tetrachloride.

Each of the two types of processes described is accompanied by serious disadvantages. In type 0, the titanium tetrachloride recovered comes from the condensed titanium tetrachloride which is contaminated by the solid chlorides from which it must be separated through a rather costly process. The condensation is obtained through the'utilization of the sensible heat of cold or cool titanium tetrachloride which requires a large llow of liquids and consequently large size heat exchangers are required. It is necessary, also, to use large size coolers and such apparatus working on turbid liquors. are always ice subject to clogging and thus do not function very satisfactorily.

In type b, the usual type of heat exchangers cannot be used since the danger of stoppage due to the deposit of -dry solid chlorides is too great. Therefore, it is necessary to atomize the -titanium tetrachloride in order to obtain a good heat exchange. Furthermore, it is necessary to have an almost pure titanium tetrachloride for atomization, for otherwise the automizers may become clogged. Apart from the foregoing diculties encountered in atomizing the titanium tetrachloride, the technique for using atomizers is inherently an exact one and does not assure a thorough washing of the chlorination gases. Consequently part of the solid chlorides remain in the chlorination gases or vapors and the subsequently recovered titanium tetrachloride is not very pure. It is' diicult also to remove dry chlorides or the slurry of chlorides which deposit at the base of the tower containing the atomizer. Normally one needs special equipment, such as Scrapers or chains, requiring costly maintenance.

This invention has as a principal object a process for the recovery of technical grade titanium tetrachloride from the chlorination gases obtained from oxidic titaniferous materials which is simple in operation and requires simple and inexpensive apparatus and thereby leads to lower processing costs. The invention provides, also, an improved process for scrubbing hot chlorination gases obtained by the chlorinationrof oxidic titaniferous materials which does not have the disadvantages of the two types of processes discussed heretofore. A further object of the invention is to provide a process for the treatment of hot gases produced by the chlorination of oxidic titaniferous raw materials which continuously yields titanium tetrachloride in gaseous phase essentially free of suspended solids in an amount at least equaling that produced by the chlorination by continuously contacting the chlorination gases with an amount of liquid titanium tetrachloride suicient to condense and wash out substantially all of the normally solid matter in liquid residual titanium tetrachloride which can be removed as a free owing liquid body thereby avoiding clogging of the apparatus and the resulting interruption of the continuity of the process.

In accordance with the process of this invention, the gases produced in the chlorinator are passed through a cooling tower or heat vexchanger where they are intimately contacted with liquid titanium tetrachloride having a desired temperature and in an amount, in excess of that vaporized by the hot chlorination gases, which condenses normally solid metallic chlorides but is insulicient to result in a net condensation of titanium tetrachloride from the chlorination gases. In other words, the amount of gaseous titanium tetrachloride coming out of the heat exchanger always at least equals the amount produced in the chlorinator. The amount of liquid titanium tetrachloride, used in excess of that vaporized, is regulated such that sufficient residual liquid is provided to wash out the condensed normally solid chlorides and contaminating solid matter suspended in the hot chlorination gases, if any, as a free owing liquid body which is readily removed from the condenser without danger of clogging the apparatus. The amount of residual titanium tetrachloride should substantially exceed the amount of solid matter collected in the condenser. The required amount of liquid titanium tetrachloride can be determined by a skilled operator as it depends on the temperature and the composition of the chlorination gases at the inlet of the heat exchanger and on the temperatures of.

the liquid titanium tetrachloride which one plans to use for washing, sprinkling or otherwiseintimately contacting the ch1orination gases, n

The temperature of the liquid titanium tetrachloride used for washing chlorination gases may vary within rather wide limits. Normally the temperature used will fall between and 136 C., which is the ebullition point of the titanium tetrachloride, but preferably is between about 70 and 130 C. An amount of liquid titanium tetrachloride, at a desired temperature within the stated; temperature range, can readily be selected so thatk the amount of gaseous TiCli coming out of the condenser is at least equal the amount introduced by the chlorination gases while suicient residual excess liquid TiCLi remains to substantially exceed the amount of condensed solid chlorides. In this way, normally solidv mattery is removed from the chlorination gases without danger of clogging and purified chlorination gases come outofthe condenser saturated with titanium tetrachloride vapors.

When one. operates. without the limits of this invenQ tion one falls. within the. types ot'previously suggested processes discussed herein with all; theirdisadvantaaes.

In the actual practice. of this invention; it has been dem,- onstreted that it is always possible to select an amount of liquid titanium tetrachloride, within the scope of this invention, which will enable one. to select a simple tower serving both as a heat exchanger and gas scrubber` without any clogging taking: place in the;r apparatus. In' particular, experience has shown that the liquid titanium tetrachloride containing up to 3,0% of; solid materials, suchv as FeCls, FeCl2, AlCla, oxidic chlorides, dust, etc.. is a free. llowing liquid body which can be easily removed from theapparatus. More particularly, according to this invention, chlorination gases are caused to llow througha heat exchange zone where they are scrubbed or washed with liquid titanium tetrachloride, at any desired ternperature, in an amount such that the liquid eilluent obtained after'v cooling the chlorination gases contains less than 30-40% of solids and such that TiCl4 comes out as gaseous vapors in an amount at least equal to that introduced by the chlorination gases. In this way the chlorination gases are washed by an amount of liquid titaniumV tetrachloride which is suicient to remove all ofthe condensed solidchlorides without the` risk of clogging the apparatus. Y

The` attached graphs, designated as Fig. l and Fig. 2, showing curves representing chlorination gases, Washed with an amount of` liquid titanium tetrachloride, within and without the scope of Vthe invention, will, facilitate an understanding of the invention. temperatures of` the, liquid` titanium tetrachloride used for washing the chlorination gasesv are plotted as the abscissa and theamount of liquid titanium tetrachloride; in kgs.. per unit. of time per 100 kg. of gaseous titanium, tetrachloride introduced by the chlorination gases are."

plotted on a logarithmic scaleas the ordinates;

The curves of Fig. 1 refer to chlorination gases ob,. tained from rutile having the following analysis:

The gases are assumed to enter the condenser at, a ternperature of 800 C. and to have a titanium tetrachloride initial condensation point, or dew-point,Y of 100 C.'

Curve I represents Ythe maximum flow of sprinkling or washing titanium tetrachloride in the heatexchanger, expressed as a functionof the temperature of, the liquid titanium tetrachloride, such that it is completely volatilizedby heat exchange with the gases from ,the chlorinator; Curve II represents a ow of an amount of liquid titanium tetrachloride through the heat exchanger, also expressed as a function of the temperature ofthe-,liquid titanium tetrachloride, such that the amountoftitanium tetrachloride contained in the gases flowing from the condenser just equals` the amount oftitanium tetra-A chloride contained in thev chlorination gases enteringe'tlie In these graphs the.

condenser. In other words, curve II represents the conditions under which there is no net vaporization of the liquid titanium tetrachloride introduced into the condenser.

Curve III represents a flow of an amount of liquid titanium tetrachloride into the heat exchanger for heat exchange with the chlorination gases such that the effluent liquid titanium tetrachloride contains not more than 30% of solids.

Curves IV, V and VI, of Fig. 2, are curves corresponding respectively to curves I, II and III of Fig. l, but represent chlorination gases, coming into the exchanger at 800 C. obtained from ilmenite ore of the following composition:

' Percent TiOz 52 FeO-Fe203 46 (Vi ferric Fe, 3/3 ferrous Fe) SiOz l The. TiCl4 dew-point of these gases is 90 C.

Other ores, ore mixtures, or concentrates when used in the chlorinator, other temperatures at which the gases are introduced into the heat exchanger and other TiC14 dew-points of such gases will give curves similar to those of the two specific illustrative examples.

In each case the three curves discussed above will delimit three principal zones A, B and C.' As shown in the two attached drawings, zone A below curve I or curve IV, corresponds to the known methods using restricted sprinkling or spraying with small amounts of TiCl4 as described earlier herein as a type b, zone C above curve II or curve V corresponds to the methods relying upon extensive condensation of vapors so that less TiCl4 in the vapor state comes out of the heat exchanger than is introduced with the chlorinated gases as discussed also earlier herein as type a.

Zone B included between curves I and II or IV and V is the zone within which this invention operates, namely, a zone between curve II and a curve approximating curve` I or a zone between curve V and a curve approximating curve IV where the amount of residual liquid TiCl4 is sutlicient to carry any solids collected therein. It is preferred to remain substantially above curve I or curve IV, i. e. between curves III and II or between curves VI` and V so that the proportion of solid chloride inthe residual liquid TiCl4 is less than 30 to 40%.

The advantages of such amethod are as follows;

.amountV of TiCl4 comes out of the heat exchanger as a vapor completely washed and cleaned in an amount which is at least equal to the. amount of TiCh produced' inY the chlorinator. v B. The solid chlorides4 are. condensed and eliminated at.the...bottom ofV the, heat exchanger a very simple manner. which can easily be: made continuous:

C... "Ehe condenser for recovering the TiCh vapors acts upon elean vapor so. that one is able to use a condenser of an ordinary type, which is dependableand. costs little.

The condenser for recovering theTiCli vapors acts upon saturated vapors and therefore with a high Goethcient. of heat exchange. In this way a small apparatus maybe used and the investment costs are accordingly reduced.

E. The quantity of contacting liquid TiCl4 within the scope of` this. invention can be relatively small, advantageously in the neighborhood of the lower lirnit which insures goodremoval of the condensed solid chlorides. In this wayf the heat exchanger can also be of a small size andI therefore relativelyinexpensive.

' F.' The heat exchanger can be asimple exchanger of conventional type, for example, either tubular, or a heat exchangersll'ed with packing rings. This is a very inlportant featureof the invent-ion. Actually the continuous scrubbingof the gases eliminates all risk of cloggingund,

the: utilzation'ot the heat of Maporization oi the. added liquid TiCl4, permitsl a highly efficient operation and consequently a small size apparatus can be used.

G. The liquid impure or contaminated residual TiCl4 ilows out of the heat exchanger almost at its boiling point and the amount thereof can be reduced to the minimum necessary for flowing out the condensed solid chlorides. Both of these features result in a saving of heat.

According to an important embodiment of the invention, it is preferable to work with hot TiCLr for contacting or scrubbing the chlorination gases, i. e. liquid TiCli at or above about 70-80" C. Good results, however, are obtained by using liquid TiCLi having a temperature of, say 30-80 C. Actually for a given amount of TiCl4 used for contacting the chlorination gases, the warmer the TiCL:L the more readily it vaporizes and consequently the smaller size of the apparatus required. At preferred temperatures when one works with liquid TiCli having a temperature in the neighborhood of 100 to 136 C. the heat exchange is practically reduced to the latent heat of vaporization and the process becomes automatic with respect to temperature controls.

Furthermore, the invention provides for all or part of the alternatives given below which can be used separately or in combination:

(a) The heat exchanger may be a column or tower in which the gases flow conntercurrent to the washing TiCl4 and the column may be iilled or packed with simple filling or surface extending materials, for instance, Raschig rings, thereby assuring extended contact between the gases and the liquid TiCl4 and the necessary amount of heat exchange surface. Y

(b) Part, at least, of the TiCLicoming out of the heat exchanger as vapor may be condensed and returnedto the exchanger to serve for spraying or otherwise intimately contacting the hot gases with liquid TiCl4.

(c) Residual impure TiCl4 may be separated and at least part thereof, after separating impurities, returned to the exchanger to serve for scrubbing the hot gases.

(d) The separation of the purified residual liquid TiCl4 may be preferably accomplished by distillation and condensation with the removal of occluded gases.

(e) By addition of any of known appropriate purifying agents, such as oil, for instance, to the residual TiCl4 a further purification of the 'I`iCl4 may be simultaneously obtained.

(f) The TiClq. product may be and preferably is taken in part, at least, from the residual liquid TiCL:= after separation from its impurities. i

The invention has as a particularly desirable embodiment, a cyclic process for the preparation of TiCl4 involving passing the gases coming from a chlorinator through a heat exchanger where they are scrubbed or sprayed with liquid TiCl4, preferably hot' liquid TiCl4, at a rate between the limits hereinbefor'e defined, condensing the TiCl4 coming out as vapor, separating the residual liquid TiCLi owing through the heat exchanger and returning to the heat exchanger the TiCli thus obtained diminished by the net production of TiCla. The net production of TiCl4 can either be taken from the condensed' TiCLi which comes out of the heat exchanger as vapor or preferably from the TiCLi separated from the residual liquid TiCl4 or from bot-h.

On the attached drawing-s, two examples of apparatus suitable for use in the practice of the invention are shown diagnammatically.

Fig. 3 is a diagrammatic representation of one embodiment of the invention in which the heat exchanger is shown in vertical section.

Fig. 4 is a diagrammatic representation of an arrangement suitable for the practice of a cyclic process according to the invention, constituting a second embodiment, various elements being shown in vertical section.

fIn Fig. 3, exchanger 1 is provided with packing rings 10. vGases containing a quantity Q of TiCl-i from a 'chlorinator are introduced into heat exchanger 1 through conduit V2, and liquid -TiCl4, at the rates previously discussed, are introduced into the top of the heat exchanger 1 through conduit 3. Residual gases containing vapors of 'IiCl4 in a quantity at least equalling Q ow out of the heat exchanger 1 through conduit 4 into condenser 5. The residual TiCl4 carrying impurities ows out conduit 6. The quantity of TiCl4 used for contacting the chlorination gases preferably is such that the solid impurities are less than 30% of the residual TiCl4.

Fig. 4 illustrates an arrangement for practicing a cyclic process in accordance with the invention. The following example using this arrangement will further illustra-te the invention:

Example Rutile chlorination gases coming from chlorinator 7 flow through conduit 2 into heat exchanger 1, which is insulated and provided with Raschig rings 10.

The chlorination gases possess the following characteristics:

The liquid TiCli introduced in 3a, 3b, has the following characteristics:

Temperature of the liquid for spraying C. Spraying rate 2,420 kgs./h. (1500 kgs. through 3a and 920 kgs. through. 3b).

In condenser 5, one condenses clean TiCl4, of which about v1500 kgs./h. ows back into the exchanger through 3a.

Through conduit 6, 920 kgs./h. off TiCl4 are owed,

- carrying solid impurities at a concentration of 2.62%

(less than 30%). at B.

The working characteristics are:

The net production is then collected Pressure loss in the exchanger less than 50 mm. water.

All thesequantiteshre conventionally employed in industrial processes. v

The TiCli coming out as vapor through conduit 4 is condensed in condenser 5 and the residual gases are removed through conduit 8 at about 20 C., for example. Condensed TiCli, in the neighborhood of C., flowing through conduit 9 is returned to the exchanger, except such part of the condensed TiCl4 as is taken off at B.

The impure residual TiCLi flowing out through conduit 6, at about 110 C., ows into evaporator 11 containing a heating element 12. The evaporator is supplied with oil for purifying the liquid TiCl4 through conduit 13- and slurryis discharged through outlet 14 and sent to drum dryers or the like (not shown) in order to recover the TiCl4 entrained in the slurry. The TiCl4 flowing-out through conduit 15 is condensed in the-condenser '16 and residual gases are removed through conduit 17 at about 20 C., .-for example. After cooling-at least a part of the TiCll Aliqueiied in condenser 16 from about 136 C. to about 110.C. in cooler 18, it is passed through conduit V3b to the heat exchanger 1,

agrego?? .Onecan collect all or part ofthe .net production at B.

Preferably, .at least a part vof the .net production of TiCLi is collected vfrom the clean vapors recovered from the evaporator 11. For instance, purified liquid TiCl4 can be discharged at A .fromconduits 20 and 19 as an overflow `from condenser 16. For example, 2000 kgs./h. of cleansed TiCl4 could be introduced through 3a and 420 .kgs/h. through .3b.

If the ore treated is ilmenite andthe same amount of liquid TiCl4 is used .for washing the chlorination gases, the residual Aliquid TiCLr would contain 35% of solid matter. Under such circumstances, one should reduce the solid content of the residual liquid TiCls 'toV about 15% by washing with 3340 kgsJh.

The general advantages of the present invention have already been mentioned. The cyclic process, included purely for illustrative purposes, Vhas these and certain other advantages, among which are the following:

l. Due to the fact that the exchanger 1 is supplied with liquid TiCl4 from apparatus elements which operate at constant `temperatures(-condenser 5 andV cooler 18), the process is essentially continuous and practically foolproof. As a result, -only the quantity of TiCl4 in circulation need be varied to suit the nature of the lchlorination gases, and this can be very easily regulated.

2. All of the equipment is completely air-tight thereby eliminating risks of -contamination by moisture.

3. Mechanical devices for circulating tluids (pumps, etc.) are completely eliminated and consequently abrasion problems'resulting in costly maintenance are likewise eliminated.

4. Through'this process 4onecan recover 'liCla from chlorinated raw materials which are high in impurity content (especially iron).

5. The process can be absolutely continuous for the elimination of impurities.

6. The process provides for the possibility of adding `oil or other products into the evaporator 'for purification of the residual TiCla.

7. The spraying and scrubbing liquid being clean, no clogging ditiiculties are encountered in the pipes and condensers.

8. ln the spraying circuit used for collecting TiCl4 for washing the chlorination gases one can withdraw the TiChl when it is in the vapor state and rectify it to eliminate SiCl4.

9. The invention enables one to achieve, through very simple and new means, the condensation of TiCl4 as it comes from the chlorinator and without the risk of the deposit of solid impurities; `the process being in ultimate analysis a scrubbing -of the TiCl4 vapors before their condensation.

It will be understood that gases obtained bythe chlorination of oxidic titaniferous .materials usually contain substances which are normally solid, normally liquid and normally gaseous at room temperatures and that such substances are referred to herein respectively as normally solid, normally liquid and normally gaseous substances.

While the foregoing specification sets forth numerous details and examples to illustrate the practice of this invention, it will be understood that they may be varied widely without departing from the spirit or the scope of the disclosed invention which is intended to be defined by the .appended claims.

We claim:

l. A process for continuously separating normally solid metal chloride from hot gases containing mixed vapors of `such chloride and TiCl4, which'comprises continuously flowing a stream of said gases into a heat exchange zone, continuously contacting and scrubbing said gases vin said zone with an inflow of liquid TiCl4, providing in 'said liquid inflow an amount of "TiCle at least sufcient by itself both to cool said stream below the condensation temperature of said normally 'solid chloride and to maintain a `free tlow lof liquid 'TiC-h through said zone, yet lkeeping the amount and temperature of said liquid inow insufcient to cool said stream below the dew point of its TiCl4 content, continuously collecting the resulting condensed solids `in said flow of liquid TiCl4 'and washing them out of -said zone therein, continuously taking off from said zone gases containing TiCli vapors in an amount 4at least equal to the amount thereof contained in said inllowing stream of hot gases, andvremoving from said zone -in the outtlowing metal -chlorides substantially all the heat abstracted from said stream in said zone.

2. A process for continuously separating normally solid metal chloride from hot gases containing mixed vapors of such chloride and TiC14, which comprises continuously owing a stream of said gases into a heat exchange z one, continuously contacting and scrubbing said gases in said zone with an inflow -of liquid TiCl4 at a temperature of 80 to 136 C., providing in said liquid linflow an amount of TiCle at least sucient by itself both to vcool said stream below Vthe condensation temperature of said normally solid chloride and to maintain a free ow of liquid TiCl4. through said zone, yet keeping the amount and temperature of said liquid inow insuticient to cool said stream below the dew point of itsV TiCli content, continuously 4collecting the resulting condensed solids in said 'flow of liquid TiCl4 and washing them out of said zone therein, continuously taking ott' from said zone gases containing TiCl4 vapors in an amount at least equal to the amount thereof contained in said intlowing stream of hot gases, and Vremoving from said zone in the outowing metal chlorides substantially all the heat abstracted from 4said stream in said zone.

I3. AY process for continuously separating normally solid metal chloride from hot gases produced by the chlorination of oxidic titaniferous material, said gases containing substantially all the metallic chloride vapors produced in the chlorination, which comprises continuously owing a stream of said gases into a heat exchange zone, continuously contacting and scrubbing said gases in said zone with an inflow of liquid TiCli, providing in said liquid inflow an amount of TiCl4 at least suicient by itself both to cool said stream below the condensation temperature of said normally solid chloride and to maintain a free flow of liquid TiCl4 through said zone, yet keeping the amount and temperature of said liquid inflow insutcient to cool said stream below the dew point of its TiCl4 content, continuously collecting the resulting condensed solids in said ow `of liquid TiCl4 and Washing them out of said zone therein, continuously taking off from said zone gases containing TiCl4 vapors in an amount at least equal to the amount thereof contained in said inowing stream -of hot gases, and removing from said zone in the outflowing metal chlorides substantially all the heat abstracted from said stream in said zone.

4. A process for continuously separating normally solid .metal chloride from hot gases containing mixed vaporsof such chloride `and TiCl4, which comprises continuously owing a vstream of said gases into a heat exchange zone, continuously contacting and scrubbing said gases in said zone with an intlow of liquid TiCl4, providing in said liquid inilow an amount of TiCl4 at least sufiicient by itself both to cool said stream below the con- -densation temperature of said normally solid chloride and to maintain a free How of liquid TiCl4 through said zone, yet keeping the amount and temperature of said liquid inow insuicient to cool. said stream below the dew point of its TiCLt content, continuously collecting the resulting condensed solids in said ilow of liquid TiCl4 and Washing them out Iof said zone therein, continuously taking off from said zone gases containing TiCl4 vapors in an amount .at least equal to the amount thereof contained in said intlowing stream `of hot gases, removing from said zone in .the outowing metal chlorides substantially all the heat abstracted from said stream in said zone, coneinem?? tinuously condensing TiCl4 from said oiftake gases to obtain a liquid `TiCLi product, andi-returning -at least apart of said product into said zone to continue said inilow of liquid TiCl4.

5. A process for continuously separating normally solid metal chloride from hot gases containing mixed vapors of such chloride and TiCl4, which comprises continuously flowing a stream of said gases into a heat exchange zone, continuously contacting and scrubbing said gases in said zone with an inflow of liquid TiCl4, providing in said liquid inow an amount of TiCl4 at least suficient by itself both to cool said stream below the condensation temperature of said normally solid chloride and to maintain a free flow of liquid TiCl4 through said zone, yet keeping the amount and temperature of said liquid inow insufficient to cool said stream below the dew point of its TiCl4 content, continuously collecting the resulting condensed solids in said -ow of liquid TiCl4 and washing them out of said zone therein, continually removing from said zone liquid TiCl4 containing solids collected in said zone, continuously taking olf from said zone gases -containing TiCL; vapors in an amount at least equal to the amount thereof contained in said intlowing stream of hot gases, removing from said zone in the outflowing metal chlorides substantially all the heat abstracted from said stream in said zone, vaporizing TiCl4 from said liquid TiCla removed Afrom said zone, condensing resulting vapors to yobtain a liquid TiCl4 product, and returning at least a part of said liquid TiCl4 product into said zone to continue said liquid inilow.

6. A process for continuously separating normally solid metal chloride from hot gases containing mixed vapors of such chloride and TiCl4, which comprises continuously flowing a stream of said gases into a heat exchange zone, continuously contacting and scrubbing said gases in said zone with an inflow of liquid TiCl4, providing in said liquid inflow an amount of TiCl4 at least sufficient by itself both to cool said stream below the condensation temperature of said normally solid chloride and to maintain a free flow of liquid TiCl4 through said zone, yet keeping the amount and temperature of said liquid inflow such that a substantial amount of the liquid inflow is vaporized by the heat of said gases, continuously collecting the resulting condensed solids in said ow of liquid TiCl4 and washing them out of said zone therein, continuously taking ot'f from said zone gasescontaining TiCl4 vapors in an amount substantially greater than the amount thereof contained in said inflowing stream of hot gases, and removing from said zone in the outtiowing metal chlorides substantially all the heat abstracted from said stream in said zone.

7. A process for continuously separating normally solid metal chloride from hot gases containing mixed vapors of such chloride and TiCl4, which comprises continuously flowing a stream of said gases into a heat exchange zone, continuously contacting and scrubbing said gases in said zone with an inflow of liquid TiCl4, providing in said liquid inflow an amount of TiCl4 at least suticient by itself both to cool said stream below the condensation temperature of said normally solid chloride and to maintain a free flow of liquid TiCl4 through said zone, yet keeping the amount and temperature of said liquid inflow insuicient to cool said stream below the dew point of its TiCl4 content, continuously collecting the resulting condensed solids in said ow of liquid TiCl4 and washing them out of said zone therein, continually removing from said zone liquid TiCl4 containing solids collected in said zone, continuously taking of from said zone gases containing TiCl4 vapors in an amount at least equal to the amount thereof contained in said inowing stream of hot gases, removing from said zone in the outowing metal chlorides substantially all the heat abstracted from said stream in said zone, vaporizing TiCl4 from said liquid TiCl4 removed from said zone, condensing resulting vapors to obtain a liquid TiCl4 product, continuously 'condensing TiCl4 from said offt'ake gases? tof obtain another liquid TiCLi product, and returning' i'nto',

said zone a quantity of said products suicient to maintain said liquid inflow.

' 8. A process for continuously separating normally solid metal chloride from hot gases produced by the chlorination of oXidic titaniferous material, said gases containing substantially all of the metallic chlorides vaporized in the chlorination, which comprises con` liquid inflow insufcient to cool said stream below thev dew point of its TiCLi content, continuously collecting the resulting condensed solids in said ow of liquid TiCl4 and Washing them out of said zone therein, continually removing from said zone liquid TiCl4 containing solids collected in said zone, continuously taking off from said zone gases containing TiCl4 vapors in an amount at least equal to the amount thereof contained in said inowing stream of hot gases, removing from said zone in the outflowing metal chlorides substantially all the heat abstracted from said stream in said zone, vaporizing TiCl4 from said liquid TiCl4 removed from said zone, condensing resulting vapors to obtain a liquid TiCl4 product, continuously condensing TiCl4 from said olftake gases to obtain another liquid TiCl4 product, returning into said zone substantially all said last mentioned product and suflicient of said first mentioned product to maintain said liquid inflow, and recovering the remainder of said first mentioned product as a liquid TiCl4 purified by the process.

9. A cyclic process for cooling and separating out normally solid components from hot gases produced by the chlorination of oxidic titaniferous material, said gases containing `substantially all of the metallic chlorides vaporized in the chlorination, which comprises continuously flowing said gases through a heat exchange zone, continuously and intimately contacting them in said zone withra ow of liquid titanium tetrachloride to cool the gases and condense solids therein, the amount of said liquid titanium tetrachloride being such that there is a substantially greater amount of titanium tetrachloride vapors flowing out of said zone than introduced by said gases but such that a residual amount of liquid titanium tetrachloride ows out of said zone which contains not more than 30-40% solids collected therein, continuously removing a stream of residual titanium tetrachloride containing said solids, vaporizing at least a portion of the removed liquid titanium tetrachloride and next cooling and condensing the vapors to liquid titanium tetrachloride thereby obtaining purified residual liquid titanium tetrachloride, returning at least a part of the puried residual liquid titanium tetrachloride to the heat exchange zone to cool additional gases, continuously cooling the residual gases owing out of said zone to form condensed liquid titanium tetrachloride, and returning into said zone a quantity of said condensed liquid titanium tetrachloride and purified residual liquid titanium tetrachloride suicient to maintain said ow.

lO. A cyclic process for cooling and separating out normally solid components from hot gases produced by the chlorination of oxidic titaniferous material, said gases containing in vapor phase substantially all of the metallic chloride, vaporized in the chlorination, which comprises continuously flowing said gases through a heat exchange zone, continuously and intimately contacting them in said zone with a flow of liquid titanium tetrachloride to separate solids from the gases, the amount of said liquid titanium tetrachloride being such that there iS a substantially greater amount of titanium tetrachloride va,- PQIS owiug out of said zone than introduced by said gases but such that a residual amount of free owing liquid titanium tetrachloride flows out of said zone containing not more than 30-40% collected solids, continuously removing a stream of residual titanium tetrachloride containing said solids, continuously separating a purified residual liquid titanium tetrachloride from solids in said outflow of residual titanium tetrachloride apart from said heat exchange zone, continuously cooling the resid? ual gases owing out of said zone to form condensed liquid titanium tetrachloride, and returning into said zone most of the quantity of the condensed liquid titanium tetrachloride and puriiied residual liquid titanium tetrachloride to contact a further flow of gases.

11. A cyclic process for recovering titanium tetrachloride from hot gases produced by the chlorination of oxidic titaniferous material, said gases containing substantially all of the metallic chlorides vaporized in the chlorination, which comprises continuously owing said gases through a heat exchange zone, continuously and intimately contacting them in said zone with a flow of liquid titanium tetrachloride to separate solids from the gases, the amount of said liquid titanium tetrachloride being such that there is a substantially greater amount of titanium tetrachloride vapors owing out of said zone than introduced by said gases but such that a residual amount of liquid titanium tetrachloride flows out of said zone which contains not more than 30-40% solids collected therein, continuously removing a stream of residual titanium tetrachloride containing said solids, continuously vaporizing titanium tetrachloride from the removed residual titanium tetrachloride and next continuously condensing the vaporized residual titanium tetrachloride to form puriiied liquid residual titanium tetrachloride, continuously cooling the residual gases flowing out of said zone to form condensed liquid titanium tetrachloride, returning into said Zone suicicnt of the condensed liquid titanium tetrachloride and puried residual liquid titanium tetrachloride to maintain said ow, and recovering excess titanium tetrachloride not returned to said zone.

12. A continuous cyclic process for recovering titanium tetrachloride from h.0t gases produced by the chlorination of oxidic titaniferous material, said gases containing vsubstantially all of the metallic chlorides va porized in the chlorination, which comprises continuously iiowing said gases in a vertically disposed direction through a heat exchange zone provided with surface extending material, continuously and intimately contacting them in said zone with a counter current flow of liquid titanium tetrachloride to condense solids therein, the amount and temperature of said liquid titanium tetrachloride being such that there is a substantially greater amount of titanium tetrachloride vapors owing out of said zone than introduced by said gases but such that a residual amount of liquid titanium tetrachloride flows out of said zone which contains not more than E30-40% solids collected therein, continuously removing a stream of residual titanium tetrachloride containing said solids, continuously vaporizing titanium tetrachloride` from the removed residual titanium tetrachloride and next continuously condensing the vaporized residual titanium tetrachloride to form purified residual liquid titanium tetrachloride, continuously cooling the residual gases owing out of said zone to form condensed liquid titanium tetrachloride, returning into said zone at the temperatures of said flowsuicient of the condensed liquid titanium tetrachloride and purified residual liquid titanium tetrachloride to maintain said flow, and recovering liquid titanium tetrachloride substantially free of dissolved solids from an excess of titanium tetrachloride not returned to said zone.

13. The process asdescribed in claim 12, the counter current flow of liquid titanium tetrachloride being introduced into the heat exchange zone at a temperature of 10G-136 C.

14. The process as described in claim 12, the iiow of liquid titanium tetrachloride being introduced into the heat exchange zone not exceeding 10 times the weight of titanium tetrachloride vapors in the iiow of said gases and the residual titanium tetrachloride flowing out of said zone containing more than 1% of solids.

References Cited in the tile of this patent UNITED STATES PATENTS

Claims

1. A PROCESS FOR CONTINUOUSLY SEPARATING NORMALLY SOLID METAL CHLORIDE FROM HOT GASES CONTAINING MIXED VAPORS OF SUCH CHLORIDE AND TICL4, WHICH COMPRISES CONTINUOUSLY FLOWING A STREAM OF SAID GASES INTO A HEAT EXCHANGE ZONE, CONTINUOUSLY CONTACTING AND SCRUBBING SAID GASES IN SAID ZONE WITH AN INFLOW OF LIQUID TICL4, PROVIDING IN SAID LIQUID INFLOW AN AMOUNT OF TICL4 AT LEAST SUFFICIENT BY ITSELF BOTH TO COOL SAID STREAM BELOW THE CONDENSATION TEMPERATION OF SAID NORMALLY SOLID CHLORIDE AND TO MAINTAIN A FREE FLOW OF LIQUID TICL4 THROUGH SAID ZONE, YET KEEPING THE AMOUNT AND TEMPERATURE OF SAID LIQUID INFLOW INSUFFICIENT TO COOL SAID STREAM BELOW THE DEW POINT OF ITS TICL4 CONTENT, CONTINUOUSLY COLLECTING