US2900234A - Manufacture of titanium tetrafluoride - Google Patents

Description

United States Patent MANUFACTURE OF TITANIUM TETRAFLUORIDE Ralph B. Jackson, Dover, Donald H. Keily, Gladstone, and Robert V. Townend, Morris Township. Morris County, N.J., assignors to Allied Chemical Corporation, a corporation of New York No Drawing. Application February 11, 1957 Serial No. 639,225

8 Claims. (Cl. 23-88 This invention relates to processes for manufacture of anhydrous titanium tetrafluoride.

In accordance. with known art, titanium tetrafiuoride, TiF may be made by reacting metallic titanium or titanium' dioxide with elemental fluorine, or by passing anhydrous HF over titanium tetrafluoride at ambient tem peratures or over metallic titanium at red heat. These methods are expensive and uneconomical, and the disadvantages entailed are obvious.

A principal object of this invention lies in provision of processes for making anhydrous titanium tetrafluoride from the usual commercially available sources of titanium, i.e. oxygen-containing titanium compounds such as ilmenite ores, titanium slags, rutiles and titanium dioxides, and from hydrogen fluoride a common industrial commodity.

Experience shows that it is not possible to make anhydrous TiF, by direct reaction of HF with titaniferous raw materials containing oxygen. Commercially available sources of titanium all contain oxygenwhich reacts with hydrogen of the HP to form water which may hydrolyze an objectionable amount of titanium fluoride to titanium oxide compounds. Accordingly, manufacture of anhydrous TiF, by direct one-step fiuorination of oxidic titaniferous raw materials is not feasible.

In accordance with the present invention, it has been found that the difllculties arising from inherent water formation and the resulting potential or actual hydrolysis may be overcome by reacting commercially available oxidic titaniferous sources of titanium with HF under certain conditions such that the titanium values of the oxidic titanifero-us starting materials are preliminarily complexed with certain metal or metals to form metal fluotitanates which, in the preferred practice of the invention, are stable hydrated fluotitanates of the metal or metals employed for titanium complexing. We find that these hydrated metal fluotitanates may be substantially completely dehydrated by heating under certain conditions which eflect elimination of all free and combined water. In this manner, titanium is maintained in the form of unhydrolyzable compounds until all water has been removed from the system. We also find that, by further heating the dehydrated metal fluotitanate at controlled higher temperatures, it is possible to volatilize the titanium values of the dehydrated metal fluotitanate and effect clean separation of titanium, as TiF, vapor, from all other compounds which may have been employed to initially complex the titanium values of the titaniferous starting material. Hence, practice of the invention involves conversion of the titanium of oxidic titaniferous raw materials to certain metal fluotitanates, in one Way or another eliminating free and combined water from the system, and thereafter separating titanium from the dehydrated metal fluotitanate as anhydrous TiF vapor which may be recovered as such or as a white solid on cooling and condensation.

More particularly, in practice of the invention an oxidic titaniferous raw material is reacted with HFin the presence of certain compounds of certain metals in such a Way as to tie up substantially all Ti in the form of a dehydratable and subsequently decomposable fluotitanate of the metal or metals used for complexing purposes. The important factors of this HF-titaniferous starting, material reaction step are the composition of initial oxidic titaniferous raw material, the particular metal. compounds.- used for complexing purposes, the particular metals of such compounds, the quantities of such compounds which are present during the reaction, quantity and form of. the HF utilized, temperatures of reaction, and the physical procedures in accordance with which the reaction of theoxidic titaniferous raw material with HF is carried out..

Metal compound which may be used to complex the titanium of the oxidic titaniferous starting material. may" be of the group consisting of oxides, hydroxides, car-.

bonates and fluorides of aluminum, barium, calcium, iron,

magnesium, and zinc, and any mixtures thereof. Preferred metals are aluminum, calcium, iron, and magnesium. Thus, it will be seen that a wide variety of metal compounds, taken singly or in admixture with one or more other metal compounds, may be utilized in practice of the invention, and the expression metal com.- pound, unless otherwise modified, as used herein em,- braces the above designated metal compound grouping.-

The term metal herein does not include silicon which? is considered as a metalloid or a non-metal. It will be understood that any one or all of the metals named will complex with titanium to form metal fluotitanates suitable for practice of the invention. To illustrate, assum.-

ing use of e.g. off-grade TiO as starting material, iron oxide alone or say a mixture of iron oxide, aluminum oxide and calcium oxide may be employed to complex,

the titanium. In the case of use of the iron oxide alone,

the fluotitanate is iron fluotitanate, and in the case ofthe mixture, the resulting complex is a mixture of iron, aluminum and calcium fluotitanates. In expressions herein such as total metal fluotitanate, the total metal is used to designate either a single metal or the total of any two or more of the metals above named.

In practice of all embodiments, the amount of titanium complexing compound employed in the reaction of oxidic titaniferous material reaction with HP is such as to provide the presence of total metal of complexing metal compound in quantity suflicient to combine with substantially all of the formable TiF to produce total-metal fluotitanate. From a more particular viewpoint, the quan-' tity of complexing metal compound employed is such as to provide in the reaction the presence of total metal of metal compound in amount sufficient to combine with at least 0.45, and in the best forms of the invention, preferably not less than half as much fluorine as is theoretically needed to react with all titanium present to form TiF Provision in the reaction mass of the fore going amounts of total metal in conjunction with the hereinafter noted quantities of HF efiects complexing of the titanium with total metal of the complexing metal compound to form total-metal fluotitanate.

Whether or not metal compound for titanium coinplexing purposes is actually added from extraneous sources to the oxidic titaniferous starting material de pends upon the composition of the latter. Natural ilmenite ores usually contain a high proportion of metal (other than Ti) compounds which may be utilized to. complex the titanium. Typical ilmenites may analyze Ti as 'IiO 53-60%; total Fe as Fe O 35-38%; Si as Si0 1.04.0%; plus smaller quantities of miscellaneous and P 0 usually as oxides.

. 3 v is iron oxide which may be utilized as a suitable metal compound for complexing the titanium. From the foregoing typical analyses, it will be observed that such ilmenites inherently contain total metal (Fe) of complexing metal compound (iron oxide) in amount more than suflicient to combine with about half as much fluorine as is theoretically needed .to react with sub:tantially all the titanium present to form TiF Accordingly, it will be understood that when utilizing in practice of the invention oxidic titaniferous raw materials, such as most i'lmenites, which inherently contain sufficient complexing metal compound to provide in the reaction mass total metal of'complexing metal compound in amount sufi'icient to combine with at least 0.45 and preferably not less than half as much fluorine as is theoretically needed to react with all titanium present to form T iF it is unnecessary to add to the oxidic titaniferous starting material or to the reaction any additional complexing metal compound from extraneous sources, ie.

in the case of most ilmenites these materials may be used as titaniferous starting materials on an as is composition basis.

Titanium slags are well known in the art, illustrative methods for making the same being disclosed in U.S.P. 2,476,453 of July 19, 1949, and U.S.P. 2.631.941 of March 17, 1953. Representative slags may analyze -Ti as TiO and Ti O 65-75%; Fe as FeO 610%; Al as A1 4-5%, Ca as CaO 03-17%; Mg as MgO 35%, Si as SiO 4-5 plus small amounts of oxides of miscellaneous metals such as Cr, V, Mn and some metallic iron. It will be noted that in titanium slags, metal compounds which may be used for titanium complexing purposes are dominantly oxides of iron, aluminum, calcium, and magnesium. Also, it will be understood that in most slags the total metal (e.g. Fe plus Al plus Ca plus Mg) of the available titanium complexing metal compounds is inherently present in amount insufficient to combine with at least 0.45 as much fluorine as is needed to react with titanium present to form TiF and facilitate formation of total-metal fiuotitanate. Hence, where the oxidic titaniferous raw material employed is such that it does not of itself contain total-metal of total complexing metal compounds in sufficient amount, an additional quantity of complexing metal compound of the type herein defined is introduced into the raw material or into the reaction in amount sufiicient to bring available total metal of complexing metal compound up to the above indicated values. p

' Rutiles usually contain upward of 90% Ti as TiO and hence inherently contain very little and wholly insuflicient amounts of complexing metal compound. while titanium sources such as impure or off-grade TiO contain no significant quantities of complexing metal compound. In these instances, the complexing metal compound deficiencies are made up, similarly as in the case of titanium slags, by incorporation of the necessary additional quantities of whatever complexing metal compound is to be employed. Regardless of the composition of the'oxidic titaniferous starting material, it will be noted that in practice of all embodiments of the invention the reaction of starting material with HF is carried out in the presence of total metal of complexing metal compound in amount sufficient to combine with substantially all of the formable TiF to produce total-metal fluotitanates, and to obtain best recoveries, reaction is carried out in the presence of total metal complexing metal compound in amount sufficient to combinewith at least 0.45 and preferably not less than half as much fluorine as is needed to react with all titanium present to form Til- T he quantity of HF employed in the complexing reaction is in amount suflicient to convert any silicon com-- pounds present to SiF all titanium present to TiF and to convert all metal compound, other than. any mjc al fluoride which may be present, to metal fluoride. It will be understood that any silicon compound in the incoming titaniferous material is eliminated from the system as SiF during the reaction. As hereafter more particularly noted, metal fluorides are suitable complexing compounds, and hence, when metal fluorides are utilized as complexing agents, the quantity of HF sup-. plied to the reaction may be correspondingly reduced.

Hydrogen fluoride may be employed in the form of anhydrous liquid or gas, or as an aqueous solution having an HF strength preferably not less than about 50%. The foregoing preferred minimum of HF concentration, in conjunction with hereinafter noted procedural features, is a factor contributing to prevention of hydrolysis of titanium compound during the reaction. As a further precautionary measure with regard to prevention of hydrolysis, and also to effect substantially complete formation of total-metal fluotitanates, it is preferred to operate with an excess of HF preferably not less than 10% over theoretical requirements.

The reaction of oxidic titaniferous starting material with HF may be carried out in any suitable externally.

heated reactor at atmospheric pressure or under superatmospheric pressure if so desired. The titaniferous material is usually relatively finely divided and may pass 200 mesh. To obtain good HF utilization, it is preferred to employ hydrogen fluoride in liquid anhydrous form, or as aqueous hydrofluoric acid of strength above about 50%, and usually about 60% HF strength. Agitation facilitates reaction. Where gaseous anhydrous HF is employed, HF gas may be contacted with the titaniferous material maintained in the form of agitated or relatively static beds, and the apparatus may be designed to facilitate feed of gaseous HF at rates such as to effect good HF utilization.

Reaction of HF with titaniferous raw material takes place at any reasonably elevated temperature, reaction being significant at temperatures upwards of e.g. 50 C. Particularly when using HP in liquid form and substantially atmospheric pressure, temperatures are preferably not higher than about 200 C., and more usually temperatures lie in the range of about -150 C.

Any complexing metal compound supplied from extraneous sources may be mixed initially with the incoming titaniferous material, or may be introduced during the course of the reaction particularly where the latter is carried out using HP in liquid form. Time of reaction is widely variable depending upon the particular operation at. hand, but in any case is sufficient to convert the titaniferous starting material to total-metal fluotitanate. Preferably, especially. when using HF in liquid form, reaction or digestion may be continued until the material in the reactor is a relatively dry, hydrated total-metal fiuotitanate, i.e. contains no significant amount of free water. We find that when HF is used in the above mentioned concentrations, and reaction procedure is such that the hydrated total-metal fluotitanate in the reactor is reduced to substantial dryness (substantial absence of free water), possibilities of titanium hydrolysis are minimized.

As indicated, it is preferred to carry out the invention process stepwise, i.e. formation of a hydrated totalmetal fluotitanate, followed by dehydration (removal of combined water), and subsequent decomposition of the dehydrated total-metal fluotitanate. While not preferred, reaction of HF and incoming titaniferous material with formation of hydrated total-metal fluotitanate and de-.

hydration ofthe same may be carried out in a more or less single continuing step, e.g. at approximate termination of the reaction of titaniferous material with HF, temperature may be raised sufficiently to dehydrate the fluotitanate thus formed. In such circumstance, maximum temperature may be high enough but not substantially higher than that needed to substantially dehydrate total-metal fluotitanate, in which instance maximum temperatureshould not exceed about 450 'C. at substantially atmospheric pressure. operating convenience, such procedure is not preferred.

In usual practice, the reaction of oxidic titaniferous material with HF proceeds at temperatures generally below about 150 C. to the point of substantial dryness of the mass in the reactor. The resulting hydrated totalmetal fluotitanate may be dehydrated in the reactor or in separate suitable equipment. In accordance with the invention, dehydration is eflected by heating the reacted mass to within the range of about 350-450 C. Purpose of this step is to eliminate all combined water from the system with substantially no decomposition of the fluotitanate. A good average temperature is about 400 C. However, on the other hand, somewhat lower or somewhat higher temperatures may be employed depending upon the particular nature of the fluotitanate at hand. For any given conditions of operation, one or two test runs will indicate optimum maximum temperature of dehydration. To insure high ultimate yields of TiF lower temperatures and longer dehydrating time intervals are preferred. End point of dehydration may be determined by cessation of weight loss of the material being dehydrated.

In accordance with the invention it has been found that the titanium constituent of the particular total-metal fluotitanates described may be separated from all other fluotitanate constituents as vaporous TiF by heating the dehydrated total-metal fluotitanates at temperature substantially in the range of 625-750 C. at atmospheric pressure. For this purpose, the dehydrated fluotitanates may be charged into a suitable externally heated sublimer equipped with means for, taking off vaporous TiF Heating is continued until exit of TiF from the sublimer substantially ceases. TiF4 vapors discharged from the sublimer may be cooled to recover anhydrous TiF as a White solid. The solid residue in the sublimer is a mixture of fluorides of the metals of the metal compounds utilized in the reaction step for titanium complexing. Thus, in the case of utilization of a titanium slag-as raw material, the solid residue in the sublimer may be a mixture of iron, aluminum, calcium, and magnesium fluorides plus some unreacted raw material. When utilizing oxidic titanifero-us starting materials which require addition of complexing metal compound from ex traneous sources, We find that the sublimer residue is particularly adaptable for use for this purpose. Experience shows the fluorides of the complexing metals react readily With the incoming raw material to form fluotitanates, a mayor advantage being that when utilizing metal fluorides as complexing metals overall consump tion of HF is materially reduced.

Temperatures mentioned herein are taken at substantially atmospheric pressure. Approximately cor-' responding temperatures at subor superatmospheric pressures may be employed. For example, at absolute pressure of about 1 mm. of Hg, dehydration temperature may be as low as 300 C., and TiF, sublimation temperature may be as low as about 500 C.

In the following examples, unless otherwise. noted, parts and percentages are by'weight, and the term metal does not include silicon which is considered herein as a non-metal.

Example 1.--Ten' parts of about 200 mesh ground ilmenite ore, analyzing total titanium as TiO 58.3 total iron as Fe O 35%, and 1.5% Si plus other oxides of metals such as Al, Ca, Mn, Mg, V, and Cr amounting to a little more than 5% of the ore, were added to about 15.9 parts of aqueous hydrofluoric acid of- 60% HF strength. The amount of HF employed was about in excess of that theoretically required to convert all Ti to TiF silica to SiF and all metals other than Ti to metal fluorides. In this particular ilmenite, the total metals (other than Ti) inherently present were suflicient to combine with about 0.54 as much fluorine as From standpoint of 6 was required to react with all Ti present to produce TiF that is, the total metals (other than Ti) were inherently present in amount at least sufficient to combine with all TiF to form total-metal fluotitanate. Hence, no addition of extraneously introduced titanium complexing metal compound was necessary. The foregoing mixture was digested with agitation at about 100 C. SiF and water vapor passed off, and digestion was continued to approximate dryness. Drying (removal of free water) was completed by heating for several hours at about 110 C. The resulting hydrated total-metal fluotitanate cake, mostly iron fluotitanate, was broken up and crushed to pass 100 mesh, The finely divided material was heated for about one hour at temperature of about 400 C. at atmospheric pressure to drive oif all combined water. On completion of dehydration, the material showed a weight loss of about 5.9%, an amount corresponding approximately to 2H O hydration of the undehydrated fluotitanate. The dehydrated fluotitanate was heated at about 700 C. at atmospheric pressure for approximately one hour. TiF sublimed off by decomposition of the fluotitanate complex, was condensed and recovered, and weight loss of the metal fluoride residue in the sublimer was about 62% (dry basis), showing a recovery of TiF of about 96% of theory.

Example 2.-In this run, the oxidic titaniferous raw material employed was approximately 100 mesh titanium slag analyzing total Ti as TiO 71.8%, total iron as FeO 6.6%, A1 as A1 0 9.4%, Si as SiO 7.7%, plus small amounts of oxides of other metals such as calcium, magnesium,-vanadium, chromium and manganese. Twenty parts of the slag were added in small increments while agitating to about 39 parts of aqueous hydrofluoric acid of 60% HF strength. The mixture was digested with agitation for about an hour at about C. at atmospheric pressure. About 2.4 parts of Ca(OH) in the form of 325 mesh powder were added, and the resulting mass was further digested at temperature of about C. SiF and water vapor passed off, and digestion was continued to approximate dryness. Drying (removal of free water) was completed by heating for several hours at about C., and the resulting hydrated total-metal fluotitanate cake,, mostly iron, aluminum and calcium fluotitanates, was broken up and crushed to pass 100 mesh. In the particular titanium slag employed, the total metals (other than Ti) inherently present were suflicient to combine with about 0.3 as much fluorine as was required to react with all Ti present to produce TiF that is, the total metals (other than Ti) inherently in the slag Were present in amount insufiicient to combine with all TiF to form total-metal fluotitanate. By addition of the Ca(OH) the total metals (otherthan Ti) content of the reaction mass was brought up to a value sufficient to combine with about 0.46 as much fluorine as is required to react with all Ti present to produce TiF that is, after addition of the calcium of the Ca(OH) the total metals (other than Ti) were present in amount sufiicient to combine with mostly all Tilto form total-metal fluotitanate. The amount of HF employed in the digestion operation was about 10% in excess of that theoretically required to convert all Ti t0 TiF silica to SiF and all other metals other than Ti to metal fluoride. The above-described finely divided total-metal fluotitanate material was heated for about one hour at temperature of about 400 C. at atmospheric weight loss of the solid metal fluoride residue in the '7 sublimer was about-50.8% (dry basis), showing a TiF recovery of about 82.5% of theory.

Example 3.In this run, the oxidic titaniferous raw material employed was the same as the titanium slag of Example 2. Ten parts of the slag were added in small increments while agitating to about 17.4 parts of aqueous hydrofluoric acid of 60% HF strength. The mixture was digested with agitation for about an hour at about 80 C. at atmospheric pressure. About parts of the solid metal fluoride sublimate residue of Example 2 were added. The residue comprises approximately, about 24% TiF 19% FeF 15% AlF 12% MgF and 28% CaF and the resulting mass was further digested at temperature of about 100 C. SiF and water vapor passed oif, and digestion was continued to approximate dryness. Drying (removal of free water) was completed by heating for several hours at about 110 C., and the resulting hydrated total-metal fluotitanate cake, mostly iron, aluminum and calcium fluotitanate was broken up and crushed to pass 100 mesh. As indicated in Example 2, the total metals (other than Ti) inherently present in the initial slag were suflicient to combine with about 0.3 as much fluorine as was required to react with all Ti present to produce TiF i.e. the total metals (other than Ti) inherently in the slag were present in amount insuflicient to combine with all TiF to form total-metal fluotitanate. By addition of the 5 parts of solid metal fluoride sublimate residue of Example 2, the total metals (other than Ti) content of the reaction mass was brought up to a value sufficient to combine with about 0.46 as much fluorine as was required to react with all Ti present to produce TiF that is, after addition of the metal fluoride residue, the total metals (other than Ti) were present in amount suflicient to combine with mostly all TiF to form total-metal fluotitanate. The amount of HF employed in the digestion operation was about in excess of that theoretically required to convert all Ti to TiF silica to SiF and all other metals (other than Ti) of the incoming slag increment to metal fluoride. The above-described finely divided total-metal fluotitanate material was heated for about one hour at temperature of about 400 C. at atmospheric pressure to drive off all combined water. On completion of dehydration, the material showed a weight loss of about 11.2%, an amount corresponding approximately to 4H O hydration of the undehydrated fluotitanate. The dehydrated complex fluotitanate was heated at temperature of about 700 C. at atmospheric pressure for about an hour. TiF sublimed oil by decomposition of the fluotitanate complex, was condensed and recovered, and weight loss of the solid fluoride residue in the sublimer was about 43.8% (dry basis) showing a TiF recovery of about 77.3% of theory on the basis of the titanium slag charged.

We claim:

1. The process for making anhydrous titanium tetra fluoride which comprises reacting at moderately elevated temperature, above about 50 C. and below temperature at which substantial dehydration of hereafter defined total-metal fluotitanate is effected, oxidic titaniferous material with HF and metal compound of the group consisting of oxides, hydroxides, carbonates and fluorides of aluminum, barium, calcium, iron, magnesium and zinc and mixtures thereof, while providing the presence of HF in the form of the group consisting of anhydrous HF and aqueous solution of HF strength not less than about 50%, and in amount suflicient to convert any silicon compound present to SiF all titanium present to TiF and to convert all metal compound other than metal fluoride present to metal fluoride, and while providing the presence of total metal of metal compound in amount sufficient to combine with substantially all TiF to form total-metal fluotitanate, heating resultant reaction materials, to temperature higher than said reaction temperature and high enough but not substantially higher than that needed .to substantially completely dehydrate totalmetal fluotitanate, for a period of time suflicient to drive off substantially all free 'and combined water to thereby form solid substantially 'completelydehydrated total-metal fluotitanate, separating said fluotitanate from evolved water; thereafter heatingthe' dehydrated total-metal fluotitanate to higher temperature above about 500 C. and high enough to decompose the same to vaporous anhydrous TiF and solid total-metal fluoride residue, and recovering said anhydrous TiF4.

2. The process for making anhydrous titanium tetrafluoride which comprises reacting, at moderately elevated temperature above about 50 C. and not substantially higher than 200 C., oxidic titaniferous material with HF and metal compound of the group consisting of oxides, hydroxides, carbonates and fluorides of aluminurn, barium, calcium, iron, magnesium and zinc and mixtures thereof, while providing the presence of HP in the form of the group consisting of anhydrous HF andaqueous solution of HF strength not less than about 50%} and in amount sufficient to convert any silicon compound present to sin, all titanium present to TiF, and to convert all metal compound other than metal fluoride present to metal fluoride, and while providing the presence of total metal of metal compound in amount suflicient to combine with substantialy all TiF, to form total-metal fluotitanate, maintaining reaction conditions for a period suflicient to convert substantially all metal present to hydrated total-metal fluotitanate, then substantially completely dehydrating said total-metalfluotitanate by heating to temperature higher than said reaction temperature and high enough but not substantially higher than that needed to substantially 'completey dehydrate total-metal fluoti-j tanate, thereafter decomposing said dehydrated total-metal fluotitanate, by heating at higher temperature above about 500 C., to vaporous anhydrous TiF and solid totalmetal fluoride residue, 'and recovering said anhydrous TiF 3. The process for making anhydrous titanium tetra fluoride which comprises reacting, at moderately elevated temperature above about 50 C. and not substantially higher than 200 C., oxidic titaniferous material with HF and metal compound of the group consisting of oxides, hydroxides, carbonates and fluorides of aluminum, barium, calcium, iron, magnesium and zinc and mixtures thereof, while providing the presence of HF in the form of the group consisting of anhydrous HF and aqueous solution of HF strength not less than about 50%, and in amount sufficient to convert any silicon compound present to SiF all titanium present to TiF -and to convert all metal compound other than metal fluoride present to metal fluoride, and while providing the presence of total metal of metal compound in amount suflicient to.

combine with substantially all HR; to form total-metal fluotitanate, heating resultant reaction materials to tem-' perature substantially in the range of 350-450 C. for a period of time sufiicient to substantially completely dehydrate total-metal fluotitanate, thereafter heating the dehydrated total-metal fluotitanate to temperature above about 625 C. to decompose the same to vaporous anhydrous TiF, and solid total-metal fluoride residue, and recovering said anhydrous TiF 4. The process for making anhydrous titanium tetrafluoride which comprises reacting at moderately elevated temperature above about 50 C. oxidic titaniferous material with HF and metal compound of the group consisting of oxides, hydroxides, carbonates and fluorides of alumlnum, barium, calcium, iron, magnesium and zinc and mixtures thereof, while providing the presence of HF in'the form of the group consisting of anhydrous HF and aqueous solution of HF strength not less than about 50%, and in amount suflicient to convert any sill-- con compound present to SiF all titanium present to TiF and to convertall metal compound other than. metal fluoride present to metal fluoride, and while providing the presence of total metal of metal compound in amount suflicient to combine with at least 0.45 as much fluorine as is needed to react with all titanium present to form TiF to thereby produce total-metal fiuotitanate, heating resultant reaction materials, to temerature higher than said reaction temperature and high enough but not substantially higher than that needed to substantially completely dehydrate total-metal fluotitanate, for a period of time sufiicient to drive off substantially all free and combined water to thereby form solid substantially completely dehydrated total-metal fluotitanate, separating said fluotitanate from evolved Water; thereafter heating the dehydrated total-metal fluotitanate to higher temperature above about 500 C. and high enough to decompose the same to vaporous anhydrous TiF and solid total-metal fluoride residue, and recovering said anhydrous TiF 5. The process of claim 1 in which the oxidic titam'ferous material contains less total metal of said metal compound than is needed to combine with all titanium present as T iF to form total-metal fluotitanate, and extraneous metal compound is introduced in quantity to provide in the reaction mass the presence of total metal of metal compound in amount sufiicient to combine with substantially all HR; to form total-metal fluotitanate.

6. The process of claim 1 in which the oxidic titaniferous material is titanium slag containing less total metal of said metal compound than is needed to combine with all titanium present as TiF to form total-metal fluotitanate, and extraneous metal compound is introduced in quantity to provide in the reaction mass the presence of total metal of metal compound in amount suflicient to combine with substantially all TiF to form total-metal fluotitanate.

7. The process of claim 1 in which the oxidic titaniferous material contains less total metal of said metal compound than is needed to combine with all titanium present as TiF to form total-metal fluotitanate, and extraneous metal compound is introduced in quantity to provide in the reaction mass the presence of total metal of metal compound in amount sufficient to combine with substantially all TiF to form. total-metal fluotitanate, the foregoing said extraneous metal compound being the solid total-metal fluoride residue of the decomposition step of a previous operation.

8. The process of claim 3 in which the oxidic titaniferous material is titanium slag containing less total metal of said metal compound than is needed to combine with all titanium present as HR; to form total-metal fluotitanate, and extraneous metal compound is introduced in quantity to provide in the reaction mass the presence of total metal of metal compound in amount suificient to combine with substantially all TiF to form total-metal fiuotitanate, the foregoing extraneous metal compound being the solid total-metal fluoride residue of the decomposition step of a previous operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,995,334 Svendsen Mar. 26, 1935 2,568,341 Kawecki et a1 Sept. 18, 1951 2,724,635 Wainer Nov. 22, 1955 OTHER REFERENCES Barksdale: Titanium, 1949, page 83.

Mellor: A Comprehensive Treatise on Inorganic and Theoretical Chemistry, Longmans, Green and Co., N.Y., 1927, vol. 7, page 67.

Claims (1)

1. THE PROCESS FOR MAKING ANHYDROUS TITANIUM TETRAFLUORIDE WHICH COMPRISES REACTING AT MODERATELY ELEVATED TEMPERATURE, ABOVE ABOUT 50* C. AND BELOW TEMPERATURE AT WHICH SUBSTANTIAL DEHYDRATION OF HEREAFTER DEFINED TOTAL-METAL FLUOTITANATE IS EFFECTED, OXIDIC TITANIFEROUS MATERIAL WITH HF AND METAL COMPOUND OF THE GROUP CONSISTING OF OXIDES, HYDROXIDES, CARBONATES AND FLUORIDES OF ALUMINYM, BARIUM, CALCIUM, IRON, MAGNESIUM AND ZINC AND MIXTURES THEREOF, WHILE PROVIDING THE PRESENCE OF HF IN THE FORM OF THE GROUP CONSISTING ANHYDROUS HF AND AQUEOUS SOLUTION OF HF STRENGTH NOT LESS THAN ABOUT 50%, AND IN AMOUNT SUFFICIENT TO CONVERT ANY SILICON COMPOUND PRESENT TO SIF4, ALL TITANIUM PRESENT TO TIF4 AND TO CONVERT ALL METAL COPOUND OTHER THAN METAL FLUORIDE PRESENT TO METAL FLUORIDE, AND WHILE PROVIDING THE PRESENCE OF TOTAL METAL OF METAL COMPOUND IN AMOUNT SUFFICIENT TO COMBINE WITH SUBSTANTIALLY ALL TIF4 TO FORM TOTAL-METAL FLUOTITANATE, HEATING RESULTANT REACTION MATERIALS, TO TEMPERATURE HIGHER THAN SAID REACTION TEMPERATURE AND HIGH ENOUGH BUT NOT SUBSTANTIALLY HIGHER THAN THAT NEEDED TO SUBSTANTIALLY COMPLETELY DEHYDRATE TOTALMETAL FLUOTITANATE, FOR A PERIOD OF TIME SUFFICIENT TO DRIVE OF SUBSTANTIALLY ALL FREE AND COMBINED WATER TO THEREBY FORM SOLID SUBSTANTIALLY COMPLETELY DEHYDRATED TOTAL-METAL FLUOTITANATE, SEPARATING SAID FLUOTITANATE FROM EVOLVED WATER; THEREAFTER HEATING THE DEHYDRATED TOTAL-METAL FLUOTITANATE TO HIGHER TEMPERATURE ABOVE ABOUT500* C. AND HIGH ENOUGH TO DECOMPOSE THE SAME TO VAPOROUS ANHYDROUS TIF4 AND SOLID TOTAL-METAL FLUORIDE RESIDUE, AND RECOVERING SAID ANHYDROUS TIF4.