SE203690C1 - - Google Patents

Description

CLASS INTERNATIONAL SWEDISH C22 b40 a: 53/00 PATENT AND REGISTRATION AGENCY Ans. 1157/1958 Mkom den 6/2 1958 attagd den 2/8 196 ARMOR RESEARCH FOUNDATION OF ILLLINOIS INSTITUTE OF TECHNOLOGY, CHICAGO, ILL. USA San in the extraction of titanium Inventor: F V Schossberger Priority requested from February 8, 1957 (USA) Present invention Shakes a method in the extraction of titanium from titanium ores and other titanium-containing raw materials. The invention is more particularly directed to a process in which a titanium solution is prepared from the titanium-containing raw material, which is fed with gaseous chlorine and then continued with an alkali metal halide, so that an alkali halo titanate precipitates.

In recent years, the need for titanium has greatly increased due to the special properties of titanium and titanium alloys. Due to the relatively low density, high corrosion resistance and high tensile strength, the use of titanium is reduced daily. A serious obstacle to the use of titanium has so far been the difficulties in producing the metal in technical form with the consequent high price. This has completely prevented the general use of the metal. - The production of titanium has been described in many places, but all these methods relate to improvements of the classical Kroll process, which is described in U.S. Pat. No. 2,205,854 and in principle consists of the reduction of titanium tetrachloride with magnesium in a bomb-like container, or of Van Arkel's iodide process ». All of these previous Wanda processes are limited to the extraction of titanium batches. The raw material is introduced into a reaction vessel, the process is carried out and the metal is then separated from the vessel. Due to local overheating, this extraction of the metal is often fashionable and expensive. Although these prior art processes have been able to satisfy limited demand for titanium, it is essential in the current state of the art and the increased demand in the future to achieve a simple, relatively inexpensive and continuous process for the production of titanium. The present invention is directed to the harp.

In the past, titanium has mainly been produced from titanium tetrachloride, which in turn has been extracted from concentrated, expensive rutile ore. It has been necessary to use this as a starting material, while the poorer ores are complex and entail high costs in order to remove contaminants. According to the present invention, on the other hand, churn rutile can be used, cheaper titanium ores such as ilmenite FeTiOs, ferrous titanium slag and other titanium-containing raw material can be converted to pure metallic titanium. As will be apparent from the following From the process according to the invention not only continuously but also cheaper raw materials and manufacturing costs.

The present invention is based on the discovery that, above all, moist potassium chlorotitanate and, in general, other moist alkali metal chlorotitanates can be dried to a fine powder by treatment with gaseous chlorine, while being heated to about 20-300 ° C. water or mother liquor in the solid chlorotitanate particles with the exception of a small fraction. According to the procedure described in more detail below. For example, after dry alkali chlorotitanate has been obtained, it can be reduced to metallic titanium, forming salts of other elements which were originally present in the RA 2 material. The metal obtained by reduction of such alkali metal chlorotitanate is fully satisfactory for technical purposes and is at least as pure as the currently available, normal, technical titanium.

An object of the present invention is to provide a continuous process for the recovery of titanium. According to one embodiment, technical titanium can be produced by reduction of dry potassium chlorotitanate and in general also other dry alkali chlorotitanates with the aid of alkaline earth metal as reducing agent under less stressful operating conditions regarding temperature and pressure than before. According to the invention, the alkali halo titanate is dried with dry hydrogen chloride at 20-300 ° C and then reduced in an inert atmosphere or vacuum with an alkaline earth metal as a solid phase reducing agent to form titanium and other end products, which are then separated from the titanium.

The method according to the invention thus comprises two steps. In the first of these, dry alkali chlorotitanates are produced from titanium-containing feedstock and in the second step, the alkali chlorotitanates are reduced to titanium. During the first step, the material is dissolved in an acidic solution, a halide is converted, precipitated and dried. During the second step, reduction of the chlorotitanate and separation of the end products are carried out.

It is important that titanium ore and many titanium-containing feedstocks can be dissolved in sulfuric acid or a mixture of sulfuric acid and hydrochloric acid as a first step in the extraction of titanium compounds from such feedstocks. After this digestion has been carried out, the new procedures of the present invention can be applied for the recovery of pure titanium metal.

The present invention can be practiced with substantially all kinds of titanium solutions. Since the preparation of such solutions for the production of titanium dioxide pigments is land-based, in the following only such factors will be considered in the known process as are necessary for the present invention to be understood. Although a complete method is described in the following, only the parts pertaining to the invention are described in more detail.

. To illustrate the present invention, reference is made to the following examples: Ilmenite ore is ground first, after passing through sieve No. 250, after which the powder is mixed with sulfuric acid, 66 ° Be. The mixture of ilmenite and acid is rapidly heated to about 80120 ° C. This heating utilizes an exothermic reaction, which heats the temperature at this range, until the reaction product should solidify or bake together. The solidified mass is then leached with either dilute sulfuric acid or a mixture of sulfuric acid and hydrochloric acid. This acid mixture can be obtained by refining acidic solutions from other stages of the process. The leaching gives an acidic solution of titanium and jam, in which insoluble material is suspended. This soluble material can be easily filtered off from the titanium iron solution or otherwise deposited.

It is then necessary to remove the iron from the solution. About 70% of the present iron can be crystallized out in the form of ferrous sulphate alone by cooling the solution to a temperature at which ferrous sulphate crystals precipitate. This precipitation usually occurs at about 5-15 ° C. The crystals are then separated from the remaining solution.

The now iron-poor 18sning is matted with gaseous chlorine cotton. This is carried out at a low temperature, suitably -10 to -20 ° C, since almost any residual jam at this temperature precipitates in the form of ferric chloride, which is then separated from the remaining titanium solution.

Solid potassium chloride was now added to the cooled titanium solution, whereby potassium chlorotitanate precipitated. This precipitation took place at about 0. ° C or a slightly higher temperature than that at which the ferric chloride precipitated. Approximately 95% of the previously basalted titanium has now been converted to solid potassium chlorotitanate. This is filtered off and the precipitate is dissolved in hydrochloric acid at room temperature. Subsequent cooling of the solution and addition of gaseous hydrogen chloride results in recrystallization and reprecipitation of the potassium chlorotitanate.

This recrystallization is not absolutely necessary, although it is part of an exemplary embodiment of the invention. You can also apply other treatments, e.g. washing with acid, to purify the chlorotitanate crystals. By recrystallization one obtains. however, sufficient purity for the fiesta andamhl. This recrystallization of the alkali chlorotitanate gives the material a special lamp for filtration and subsequent drying, since larger crystals are obtained from the hydrochloric acid solution after the first precipitation of the salt from a mixture of sulfuric acid and hydrochloric acid. The recrystallization and / or purification of the crystals is not absolutely essential. Without such treatments, however, lower quality titanium is obtained.

The precipitate is now centrifuged to separate from the accompanying liquid. The centrifugate thus obtained contains about 2-3% moisture in the form of concentrated hydrochloric acid solution. If this moisture were to remain in and around the potassium chlorotitanate crystals, there would be a marked decrease in the net yield of titanium and a deterioration in the quality.

The next step in the process is to remove such moisture without hydrolysis of the titanium compound. It has been found that the rather tightly bound mother liquor can be removed efficiently and Hit by passing a stream of dry, gaseous chlorine water through the partially dried alkali chlorotitanate, suitably at about 20-300 ° C. By this treatment one can obtain a product with a water content of about 0.01%.

The hydrochloric acid required for various steps in the present process can be recovered, recycled and reused, which is very important from an economic point of view.

The quantitative recovery of dry potassium chlorotitanate is shown by the following example: 362 parts of ilmenite, containing 50.0% of TiO2 are mixed with 724 parts of sulfuric acid, 66 ° Be, after which the mixture is rapidly heated to about 95 ° C, until the mass solidifies. The mass formed is then leached with sulfuric acid to produce a titanium solution containing 133 g of jam per liter. When this solution is cooled to 5 ° C, 79% of the dissolved iron is precipitated in the form of ferrous sulphate. After filtration, the solution contains per liter the following amounts of dissolved constituents: titanium100 g H2SO4440 g jam28g Upon further cooling of the solution to -17 ° C and matting it with gaseous chlorine, the stone part of the remaining jam precipitates as ferrochloride. After this jam was removed, 290.4 parts of solid potassium chloride was added to the solution to form small particles of solid potassium chlorotitanate. This is separated from the solution by centrifugation. The moist solid product is then redissolved in concentrated hydrochloric acid at 30 ° C. Large crystals of K2T1C16 are recrystallized and precipitated by feeding the hydrochloric acid solution with gaseous chlorine water, while the temperature is measured at -5 DEG-15 DEG C. The recrystallized material is centrifuged and dried then in a rotary kiln at 220 ° C for 3 hours and in an atmosphere of gaseous chlorine. Mier this treatment is obtained, 660 parts of dry potassium chlorotitanate.

. SA white edge, potassium chlorotitanate has never before been able to be dried to a satisfactory dryness without it becoming impossible to use it for the treatment of the present invention. The removal of physically and chemically bound water and other oxide-containing substances from alkali chlorotitanates has led to various types of hydrated titanium oxides. The present invention is thus based on the discovery that the treatment of potassium chlorotitanate with dry, gaseous chlorine chloride effectively removes virtually all of the water originally present. According to the invention, the dry potassium chlorotitanate is then reduced to the free metal.

The reduction of the present invention can be illustrated by the following equation: A2 TiCl6 +2 M—> Ti + 2 AC1 + 2 MCI2 heat in which M represents an alkaline earth metal, such as magnesium or calcium, and acts as a reducing agent, while A represents an alkali metal.

In the reduction of potassium chlorotitanate to titanium, it has been found that it is important to achieve an intimate mixture between the chlorotitanate and the reducing agent, since the reactive surfaces of the ram substances must be such that the reduction is initiated. For this reason, powdered alkali chlorotitanate and finely ground alkaline earth metal are preferred. Although the grain size joke Or abgbrande, drill the ram types of reagents have large area in relation to the volume. At present, a grain size of about 1-10 pc is preferred and good results have been obtained if the ram types of reagents have substantially the same grain size.

Although the joke is absolutely essential for the practice of the present invention, it has been found that briquetting or pelletizing the reduction mixture simplifies the handling of the material in these processes and also gives an end product which should be more advantageous on granules alone. Compression of the mixture of chlorotitanate and reducing agent can be used to produce various shaped bodies, which. shape depends on the available equipment and the equipment used to transfer the rattan to a suitable condition for final processing. After the reduction, the titanium metal is essentially in the same physical shape as the original shaped body.

If the reduction is carried out with briquettes, air must be prevented from being trapped in the briquettes. Air inclusions cause various side reactions, which have a detrimental effect on the formation of time. The oxygen in the air can thus be combined with the magnesium metal used as reducing agent and form magnesium oxide, which of course does not act as reducing agent, or the oxygen can react directly with the titanium when it is formed, so that the titanium metal is dispersed. Because this oven can react with the stuffing in the air, several by-products can be formed. The air thus only jokes 4 increases the manufacturing costs by driving the required amount of reducing agent but can also, which is more important, negate the purity of the titanium. The formation of compounds between titanium on the one hand and nitrogen and oxygen on the other hand must therefore be prevented as much as possible.

It must be noted in passing that the effect of the air must be prevented even if briquettes or pellets are not used and the reduction is carried out only with magnesium powder and alkali chlorotitanate powder. Once the dry alkali chlorotitanate is formed, it can be stored in an inert atmosphere and then reduced in such. The briquettes of reducing agent and alkali chlorotitanate should also be formed in an inert atmosphere. This is most easily done with the help of a pressure in such an atmosphere. The pressing tools can then be enclosed in a container containing argon or the like, or the mixture can also be applied in a separate, aerated, flexible container, from which the air is expelled by purging with argon, after which the briquette is formed while the pulp remains in the container. Of course, it is also possible to form a briquette in a vacuum. Of the conceivable alternatives, however, this selection is probably the most expensive relevant equipment and work. However, if you have access to a vacuum equipment, it may be more convenient to enclose the press tools vacuum-taken.

Because the titanium has an affinity for the gases normally present in the atmosphere, and either preserves or completely enhances the adverse properties of the metal, it is also essential that the reduction according to the invention be carried out in vacuo or in an inert gas, such as helium or argon. lidelgas atmosphere should be preferable.

After the material has been introduced into the inert atmosphere, the reduction can be started. It is possible to keep some excess of reducing agent, up to%, in proportion to the stoichiometrically required amount, so that the reduction is complete. Among the useful reducing agents are laminase magnesium, calcium, strontium and barium. In the present case, however, only reduction with magnesium is described. This reduction proceeds according to the following formula: TiCIG + 2 Mg - - -> Ti + 2 KO + MgCl2 heat The products KCl and MgCl2 are formed in the form of occluded crystals and are deposited to give purified, usable titanium.

A mixture of potassium chlorotitanate and metallic magnesium is heated to about 3256000 ° C in the above-mentioned inert gas. The time required for the reduction naturally depends to some extent on the applied temperature. At a temperature of about 500 ° C it takes about 3 hours to complete the reduction. The effect of time and temperature can be easily determined depending on the desired manufacturing speed and the equipment available.

After the reduction has been completed, the titanium contains the salts formed during the reduction. Although there are different ways to remove these by-products, it is preferable to leach them with dilute hydrochloric acid. It is also possible to deposit the reaction products Iran titanium metal by vacuum distillation, which constitutes an edge process of the Mom technique.

The following examples are intended to illustrate the reduction according to the invention: Example 1. 340 g of dry K 2 TiCl 4 (maximum 0.01 oxygen) are intimately mixed with 53 g of powdered magnesium, after which the mixture is formed into small briquettes in an argon atmosphere. The briquettes are kept in such an atmosphere for 3 hours at 500 ° C. After heating, the formed, reduced material is leached four times with each & again 1 1 of about 15% hydrochloric acid.

Example 2. 307 parts by weight of dry Na 2 TiCl (maximum 0.03% oxygen) are intimately mixed with 54 parts by weight of powdered magnesium, after which the mixture is formed into briquettes in an argon atmosphere. The briquettes are then kept in an argon atmosphere for 1 hour at 600 ° C. After heating, the titanium metal formed is released from the other reaction products by vacuum distillation at 600-850 ° C and a pressure of 10-2 mm.

It will be apparent how the present invention can be applied to the continuous recovery of titanium. After the reflux or the first precipitation and subsequent separation from the mother liquor, the moist chlorotitanate is introduced into an atmosphere of chlorine water. The dried material is then mixed with reducing agent and formed into briquettes. These are then passed through a heating chamber, in which the reduction takes place. The briquettes are continuously fed on a belt at one end of the reduction chamber, while the reduced briquettes fall from the opposite end of the belt.

It should also be obvious to the person skilled in the art that the present invention enables work at a suitably low temperature. Although the reduction may occur at a temperature of 325-600 ° C, it is not necessary to use temperatures above the upper part of this range.

Although it is not necessary to carry out the reduction of the reagents in the form of briquettes, this is generally clumsy.

Chlorine titanates of other alkali metals, such as sodium, rubidium and cesium, can also be used for reduction to titanium. These other chlorotitanates are dried by treatment with gaseous chlorine, and the procedure of the invention is carried out in the same manner as in the reduction of potassium chlorotitanate.

As previously pointed out, the precipitated alkali chlorotitanates can be dried almost completely by heating in an atmosphere of gaseous chlorine, which is extremely important to the present invention. British Patents 645,152, 651,729 and 652,268 are designed to produce titanium oxide pigments using the aura first steps of the process described above. However, these patents do not disclose a process for removing moisture from alkali chloride titanates, since this moisture obviously does not have a significant effect on pigment production. In the present process, on the other hand, the moisture has a strong detrimental effect on the net yield of titanium and the physical properties of the titanium, for which reason drying is extremely important. The three British patents describe the use of an acidic titanium ore solution as well as the precipitation of halogen titanates. The patents do not state anything about the production of metallic titanium.

U.S. Pat. No. 1,437,984 discloses a process for the production of refractory metals, mainly zirconium, chum and titanium. The patent discloses the use of non-molten and non-volatile salts at the reaction temperature, for example K2ZrF6, of the metal intended for reduction, together with a volatile metal! to form a product which is non-volatile or non-sublimable at the reaction temperature (see p. 1, lines 66-73). According to one reaction, K 2 ZrF 6 and sodium were used at 3153700 C. Sodium slurries at 370 ° C. The patent does not disclose the use of other solid salts, such as salts of titanium or other reducing agents, such as magnesium.

It is thus obvious that the patent specification refers in particular to a reaction which involved the use of a liquid, metallic reducing agent and a solid, volatile salt of a refractory metal. In contrast, the present reaction refers to a reaction between two solids, namely solid alkaline earth metal as a reducing agent and solid alkali chlorotitanate. A definite advantage in the present reaction is that both the starting material and the end products form solid solids and that much lower reaction temperature can be used even though the solids are always present. This lower reaction temperature was a definite technical advantage.

The embodiments described above can:. modified without exceeding the scope of the invention.

Claims (8)

Patent claim: A process in the recovery of titanium from titanium-containing raw material, wherein the titanium-containing material is prepared a titanium solution which is fed with gaseous chlorine and then added with an alkali metal halide so that an alkali halogen titanate precipitates at 20-300 ° C and then reduced in an inert atmosphere or vacuum with an alkaline earth metal as a reducing agent in solid Ins to give titanium and other end products, which are then separated as fear !. titanium. 2. A kit according to claim 1, characterized in that the titanium solution is continued with an alkali chloride, so that an alkali chlorotitanate precipitates from the solution. 3. According to claim 1 or 2 for the extraction of titanium from ilmenite, characterized in that the acidic titanium solution is prepared from the ilmenite with the aid of sulfuric acid or a mixture of sulfuric acid and hydrochloric acid, and that the sum of the titanium solution produced is continued with potassium chloride to precipitate potassium chlorotitanate. 4. According to one of the patent claims 1-3, it may be characterized in that the precipitated alkali chlorotitanate is redissolved and Mlles before it is dried. Salt according to claims 3 and 4, characterized in that the precipitated potassium chlorotitanate is dissolved in hydrochloric acid and then precipitated again by treating the hydrochloric acid solution with hydrochloric acid. 5. Set according to claim 5, characterized in that the drying is carried out at about 20300 ° C, after which the dry potassium chlorotitanate is mixed with metallic magnesium in inert gas and the mixture is heated to 325-600 ° C, in inert gas to reduce the chlorotitanate. 6. Set according to any one of claims 1-6, characterized in that the produced alkali chlorotitanate is seen and recrystallized and mechanically dried, so that a part of its water is removed before drying with chlorine. 7. San according to claim 6, characterized in that the mixture of the dried alkali chlorotitanate and finely ground alkaline earth metal in an inert atmosphere is formed into pellets or pellets. Put according to claim 8, characterized in that the mixture of the dried Other publications: potassium chlorotitanate and finely ground magnesium Gmelins Handbuch der anorganischen. Che- formed into briquettes in argonatmosfar.mie. 8 volll neu heath. Aufl. System Number 41. Titanium. Weinheim / Bergstrasse 1951, pp. 121, 122, 397, 399, 401. Request publications: Patents from