DE2507523A1 - PROCESS FOR MANUFACTURING INORGANIC SUBSTANCES - Google Patents

Description

The invention relates to a method for the production of inorganic substances, in particular of those substances for example, to remove ions from solutions based on sorption suspensions or sorption columns, also as electron exchangers, catalysts, solid electrolytes, dielectrics or the like. are usable.

Processes indicated so far for the production of inorganic sorbents are generally based on the precipitation of the solid phase from the solution of a soluble salt of a suitable metal. Have sorbents produced in this way

233 (S 8391) SPE

509835/1017

the properties of highly dispersed substances, peptize easily and only point towards organic ion exchangers moderate mechanical resistance. Another disadvantage is that in their manufacture relatively Large amounts of non-regenerable liquid waste are generated and, when sorting the end products, considerable waste is lost develop. For the reasons mentioned, inorganic ion exchangers produced from easily peptizing gels must also be used inert carriers such as asbestos, silica gel or other materials. similar properties mixed or with help inorganic or organic substances are bound. The main flaws that a wider application of such Prevent materials are based on the limited exchangeability and especially the heterogeneity of the end products as well as their low mechanical resistance.

For the reasons given above, there has been an extremely strong interest in developing a process for the production of inorganic sorbents which do not have the disadvantages mentioned and which are particularly homogeneous consist only of the active substance in question, and also have an approximately spherical particle shape, its properties do not change even after large amounts of liquid have flowed through and are easily and quickly transformed into Deposit solutions. Another requirement is that the sorbent particles have a uniform geometric shape and have high mechanical resistance, which means that these substances are

509835/1017

flow velocities can be used. The physical Properties should also eliminate the need for resorting to the end products and through disintegration and crushing prevent resulting losses.

The invention is accordingly based on the object while avoiding the disadvantages of the previous method State of the art a method for the production of inorganic sorbents with increased mechanical as well as thermal Indicate consistency.

The object is achieved according to the invention by a method which is based on the fact that a hydroxide is in the gel phase is reacted with an aqueous 0.001-5.0 molar solution or in the gas phase of a substance whose Anion with a hydrolyzable metal is a poorly soluble one Connection forms.

The hydrolyzable metal can be among americium, antimony, tin, curium, germanium, hafnium, aluminum, chromium, Manganese, niobium, lead, plutonium, tantalum, thorium, titanium, uranium, vanadium, bismuth, rare earths, zircon, iron as well a mixture of at least two of these elements can be selected.

The gel phase hydroxide can also be mixed with an aqueous solution of one of arsenic acid, hexacyanoiron (III) acid, Hexacyanoic iron (II) acid, phosphoric acid, phosphorous acid,

509835/1017

Diphosphoric acid, selenous acid, sulfuric acid, oxalic acid and telluric acid selected or with an aqueous acid Solution of alkali metal or ammonium hydrogen carbonate or hydrogen sulfide are brought to the reaction.

According to another embodiment of the invention, the hydroxide in the gel phase can also be mixed with alkali metal or ammonium antimonate (V), molybdate, sulfide, carbonate, vanadate (V) or -Tungstate (VI) together with one under nitric acid, hydrogen chloride acid, perchloric acid and acetic acid selected acid can be reacted.

A further development of the method according to the invention is that the hydroxide in the gel phase with an aqueous Solution of an alkaline earth metal hydroxide or a solution of an alkaline earth metal salt together with an aqueous solution of alkali metal or ammonium hydroxide or an aqueous solution of a complex compound of ammonium with one of copper, the platinum metals as well as zinc and iron selected substance or with gaseous hydrogen halide, hydrogen cyanide, Sulfur dioxide, rhodanic acid, hydrogen selenium or Tellurium hydrogen is made to react.

The method according to the invention for the production of inorganic substances is based on the fact that first a gel-phase hydroxide of a metal from the group of easily hydrolyzable elements is produced in the form of spherical particles, which is then reacted with a solution of an electrolyte, which has a poorly soluble compound with the mentioned

509835/1017

th metal-forming ions. This leads to an exchange of hydrogen ions or hydroxyl groups in the gel without disintegration of the particles. It has been found that in this way, and under the appropriate conditions, compounds become more numerous poorly soluble substances can be produced. With regard to their sorptive or other physicochemical properties the substances obtained in this way are at least as good as analogous compounds produced in other ways, while their mechanical properties are clearly superior.

The invention uses the knowledge that, for example, by mixing an aqueous solution of a soluble Salt of a suitable, insoluble hydroxide-forming metal or an aqueous solution of such salts with carbamide and Hexamethylenetetramine and by dispersing the resulting solution or sol at a temperature of 20-95 C in an organic or inorganic solvent, a hydroxide can be produced in gel phase, with which the inventive Task can be solved. It is necessary to choose the concentrations of the individual components so that the starting solution or the sol would be stable in the course of the dispersion in the non-aqueous medium. The gelatinization of the The solution or the sol to the solid gel phase either proceeds spontaneously without a change in temperature or as a result of increased temperature the rate of gelation being directly proportional to the temperature. By choosing a suitable ratio from aqueous to non-aqueous phase or by addition

509835/1017

surface-active substances such as a. B. condensation products of o-hydroxy-aromatic aldehydes and alkylene polyamides the particles can be prevented from coming together before gelatinization is complete. By maintaining the right Conditions result in particles that have sufficient strength and are almost spherical in shape.

The invention is also based on the knowledge that a Solution of a soluble metal salt for example before the addition of carbamide and hexamethylenetetramine either by an addition of ammonium hydroxide, an alkali hydroxide or gaseous ammonia or due to the extraction of anions is partially hydrolyzable with the aid of organic liquid anion exchangers. The hydroxide in the gel phase can also by complete anion extraction with the aid of organic liquid anion exchangers or by hydrolysis of the dispersed ones Ammonia solution up to the complete transition into the respective hydroxide, i.e. a hydrated oxide in gel form, be won.

The gel particles are separated from the non-aqueous medium and washed with distilled water or a solution of one suitable electrolytes such as ammonia, ammonium nitrate or the like. washed, making them soluble from all, not to the Substances belonging to the essential gel components are freed. The actual transformation of the hydroxide in the gel phase in the desired sparingly soluble metal compound is done with the help of a solution containing the anion in question such as B. phosphate, diphosphate, arsenate (V), hexacyanoferrate (II),

509835/1017

Contains molybdate (VI) or sulphide, The neutralization of the Hydroxyl groups formed in the course of the conversion can be carried out in such a way that either a solution is used for the conversion an acid containing the anion in question or an acidic corresponding or neutral salt together with an inert one Acid such as nitric acid, hydrochloric acid, perchloric acid, or acetic acid is used. This transformation can also be effected by action of vapors or gases that behave as acids in aqueous solution, such as hydrogen halides or hydrogen sulphide, done on the hydrogel. The conversion can be carried out under stationary and dynamic conditions. Their speed mainly depends on the type of the product to be produced and the concentration of the reacting components, in particular the hydrogen ions in the solution away. After the conversion is complete, the product is purified by washing with distilled water and drying reaction wastes and freed unreacted components, e.g. B. in the spontaneous process.

The invention is based on the further finding that the hydroxides of polyvalent metals are usually amphoteric Have character, which is noticeable in that the gel-like hydroxides act as anion exchangers in an acidic medium and in an alkaline medium as a cation exchanger works. The gels can consequently by the action of alkali metal and alkaline earth metal hydroxide solutions in the corresponding compound such as the aluminate, chromate (III), perrate (III), titanate (IV), zirconate (IV) or the like. convert.

509835/1017

The invention also makes use of the knowledge that the conversion can also be carried out with the aid of dissolved complex compounds in which the central metal atom acts as a cation in a neutral or alkaline medium. The hydroxide As a result, in the gel phase it is possible to convert those compounds into compounds other than the polyvalent, the actual Gel-forming element, also elements from the group of platinum metals as well as zinc, copper or iron.

Another feature of the invention is that, provided that the gel-forming element can react in several valency levels, such as tin, titanium, uranium and iron of PaIl _3, the conversion is also carried out by the action of aqueous solutions of these elements, which have redox properties can be. The reaction products of this conversion are sparingly soluble compounds.

According to the invention, the conversion can be carried out with the aid of a solution which contains a salt mixture of two or more elements, whereby a corresponding multicomponent system, e.g. B. a ternary or quaternary system is obtained. Similarly, multicomponent gels consisting of mixtures of hydroxides of two or more elements can also be converted .

The gel converted according to the invention can after drying with hydrogen, carbon monoxide or with another gel

509835/1 017

suitable reducing agents, ζ. B. by the so-called. Carbothermal process, reduced. If the gel contains at least elements of metal character that can be converted into the elementary metal form, alloys or compounds of two or more metals can be obtained. Under suitably chosen conditions, two- or multi-component cermets (oxide metals) or alloys can be produced which have a lower melting point than the individual metal components contained therein, all of which
Components are homogenized in their initial state at the molecular level. In this way, even metal alloys can be produced under reaction conditions and ratios,
among which these metals are usually unalloyable.

The spherical shape and the gel-like character of the particles are not impaired during conversion or further processing. Since the conversion is in principle a
Ion or electron exchange corresponds, also arise
Compounds or mixtures of compounds that were previously either
have not been made at all, or theirs
Manufacturing in other ways is much more difficult to carry out.

The present invention is illustrated in the following with reference to Embodiments explained in more detail.

EXAMPLE 1

To 1 part of an aqueous solution (1.7 mol) of zirconium oxide dichloride was with vigorous stirring 1 part of an aqueous

509835/1017

gene, 1.7 mol / l carbamide and 1.25 mol / l hexamethylenetetramine-containing solution added. The resulting solution was finely dispersed in a column ^{in silicone (90 °} C.) by means of a capillary. In the process, uniform spherical particles of solid zirconium hydroxide gel were formed, the shape of which depended on the inside diameter of the capillary and which were finally filtered off from the oily liquid. The gel particles were then washed with trichlorethylene and thereby freed from the oily residue remaining on their surface, whereupon they were introduced into an aqueous, 3% strength by weight ammonium hydroxide solution. The residues of reaction products and unreacted components are removed by repeated washing in distilled water.

EXAMPLE 2

The procedure was as in Example 1, with the difference that the solution was dispersed in silicone oil, the was located in a reactor equipped with a stirrer, whereby particles of irregular shape and size were obtained, the dimensions of which corresponded to the stirring intensity.

EXAMPLE 5

An aqueous solution containing 2.476 mol / l zirconium oxide dichloride was first obtained by extraction with a 50:50 mixture of a primary amine and xylene denitrated. The Extrak

509835/1017

tion was carried out in three stages, i; was CWhen the aqueous phase in each stage at 80 ⁰ C is heated, whereupon the extraction solution was added, after cooling, Nae I: completion of the extraction, the organic phase was separated in a separating funnel from the aqueous phase. 0.4 parts of an aqueous solution containing 1.35 mol / l carbamide and 2.7 mol / l hexamethylenetetramine were then added to one part of the aqueous solution, with vigorous stirring. The mixture was then dispersed in warm oil as described in Example 1.

EXAMPLE

Thoroughly washed zirconium (IV) hydroxide gel, which was prepared according to Examples 1-3, was with aqueous Phosphoric acid solution extracted. By using different concentrations of phosphoric acid solutions in the range of 5 «10 ^ 5 mol / 1 and reaction times of different lengths, products with different PO ^ / Zr ratios were obtained. The end products were finally washed with distilled water until neutral, followed by drying in a stream of air became.

EXAMPLE 5

To 1 part of an aqueous 2.4 M solution of iron (III) nitrate · that was previously cooled to 5 ⁰ C, was in-

509835/1017

Intensive stirring a mixture of Oo parts of an aqueous 9 m solution of Caroamide and Oj? Share an aqueous 3.5 m solution of vcTi hexamethylenetetramine sugesetst. The precipitate thus formed was dissolved gradually in a clear solution, which then in warm "load finely dispersed and was then treated in the same manner as in Examples 1 and 2. FIG.

EXAMPLE 5

Thoroughly washed iron ( III} hydroxide gel prepared according to Example 5 wu'-de sin => / M. aqueous solution of ammonium dihydrogen phosphate v -inwirhs :: ^ älas ^ -an "Here" different concentrations of As ^ iilii.iudihjai-sgs ^ pnosphate in the range of 40 - 4C0 g / l in ■ li ^ ztZ.li.eTZ ^ '^. vvasssr used »Velocity and Uciwandlu ^^ sgi ^ ad des 3isen'III) -iiydroxids in Schwsrlösliohes phosphate "would?:! iureh increase baw, decrease of animc>: iur;: dihydrOiViriphc ---- 7 _; haö "KGP.sentration set, the end product -vurdi ::; it distilled / Jass er washed.

EXAMPLE T

The procedure was as in Example 6 , with the difference that the iron (III) hydroxide gel was converted into iron (III) cyanoferrate (II) by the action of potassium cyanoferrate (II) acidified with hydrochloric acid. It was

ORIGINAL INSPECTED

509835/1017

Potassium cyanoferrate (II) at a concentration of 0.1 0.8 mol / 1 and hydrochloric acid at a concentration of 0.1 - 5 mol / 1 used, the reaction time 1 - 24 h fraud. The final product was washed with distilled water and dried, for example on spontaneous Paths or by letting them dry in the air.

EXAMPLE 8

Thoroughly washed iron (III) hydroxide gel that was prepared according to Example 5, a stream of gaseous hydrogen sulfide was in a horizontal column exposed. After the ferric hydroxide was converted into the sulfide in question, the end product became dried.

EXAMPLES 9-13

The procedure in each case was as in Examples 1-3, with the difference that hydrogels were the easily hydrolyzable Elements antimony, tin, hafnium, aluminum, chromium, niobium, tantalum, thorium, titanium and uranium were treated.

EXAMPLES 19 - _2g It was in each case as in Examples u. - 6 procedures,

509835/1017

with learning difference, that the hydroxide or hydrated oxide gels with different knowledge dipbosphoric acid, arsenic acid, hexacyanoiron (ΙΙΣ) acid.,. fi-axe.üy anoeisen {II) acid, phosphoric acid, phosphorous acid _; Selenic acid _s sulfuric acid, oxalic acid, and telluric acid were treated.

EXAMPLE 50 "

Washed titanium (IV) -hydroj: id gel with a content of 30 % iron (III) hydroxide was treated with an aqueous solution of hexacyanoiron (II) acid to form titanium (IV) iron (III) "hexacyancferrate A concentration of the Hezacyanoiron (II) acid in the range 0.1-1 mol / i was used, the reaction time being 1-2i hours The end product was washed with distilled water and dried in a stream of air .

The procedure was as in Example 30, with the difference that the conversion of the iron (III) hydroxide into the sulfide was carried out by the action of aqueous solutions of ammonium, potassium or sodium sulfide. Solutions with Konasntrs. tions of 0.1 - k mol / l used j where the Fsaktionsaeifc at a temperature of 20-90 ⁰ C was 1-24 h. The end product was

0 9 8 3 5/1017

first washed with distilled water and noisily with acetone, whereupon it was dried under reduced pressure.

EXAMPLE 32

The procedure was as in example i8, with the difference that that a washed hydrogel made of zirconium (IV) phosphate, this by converting zirconium hydroxide with phosphoric acid was made with solutions of salts (preferably chlorides) of the poorly soluble sulphide-forming elements cadmium, Cobalt, copper, nickel, lead, zinc αηα iron has been treated, The hydr ^ el ^ produced in this way then with gaseous Hydrogen sulfide to form a mixed hydrogel of zirconium (17) phosphate and sulfide lea concerned Elements implemented.

EXAMPLE 35

Thoroughly washed titanium (IV) hydroxide gel was made reacted with aqueous barium hydroxide solution. During the investigations, concentrations of the hydroxide were in the range of

10 mol / 1 used up to saturated solution. With different long reaction times, products with different Ba / Ti ratios were obtained, those with distilled Washed with water and dried.

OftenJßJNAL INSPECTED

509835/1017

EXAMPLE 3 **

Thoroughly washed aluminum hydroxide gel was reacted with a solution of copper (II) ammonia complex. In the investigations, different complex concentrations in the range of 10-1 mol / 1 were used, with products with different Cu / Al ratios being obtained with reaction times of different lengths. After the conversion had ended, the product was washed with dilute ammonium hydroxide solution, calcined and, if necessary, treated ^{in a hydrogen atmosphere at a temperature above 300 ° C. to reduce metallic copper.}

EXAMPLE 35

Thoroughly washed uranium (VI) hydroxide gel was reacted with ammoniacal copper (II) and nickel (II) chloride solution. Various concentrations of 0-1 mol / 1 were used in the investigations, whereby products with different Cu / Ni / U ratios were obtained. After the conversion was complete, the product was treated as in Example J> k.

EXAMPLE 36

The procedure was as in Example 35, with the difference that mixed gels of uranium and iron hydroxide in different

509835/1017

different circumstances were used.

EXAMPLE 37

Thoroughly washed uranium (VI'-hydroxide gel was reacted with aqueous iron (II) salt solution (preferably chloride). In the investigations, solutions of different iron (II) salt concentrations with different reaction times were used U (VI) and Pe (II), derei, product was a dark to black, gel-like substance. After completion of the process, the product was washed with distilled water, dried or reduced as in Example 3 ^.

EXAMPLE 38

The pH of a 10 molar solution of a soluble salt of the elements listed in Table I below was adjusted to 3 with nitric acid, whereupon 1 g of zirconium (IV) phosphate sorbent prepared according to Example k was added to the corresponding solutions. The suspension thus formed was shaken up; After the sorption equilibrium had been established, the concentration of the metal remaining in the solution after sorption was determined. The determined values of the distribution coefficient D (ml / g) are listed in Table I below.

509 8 35/1017

Table I.

Values of the distribution coefficient D (ml / g) for the sorption on zirconium (IV) phosphate

Element Cerium Cesium Sodium Strontium Thorium Zinc D ΙΟ ⁴ ~ 10 ³ 30.4 10 ³ 1O ⁴ 1O ³

EXAMPLE 39

Solutions of the following compounds in a concentration of 0.1 mol / 1 at a Flow rate of 0.5 ml · cm · min. The amount retained was based on the measurements in the eluate (in mol / g): HCl - 0.85; ENT - 0.50; H ₂ SO ₄ - 0.50; H PO ₄ -1, 4l; H AsO ₁₁ - l, ₄ H 09j Pe (CN) ₆ - 0.69; NaOH - 0.30.

509835/1017

Claims (8)

-IO _ Claims fy. Process for the production of inorganic sorbents with increased mechanical and heat resistance, characterized by the reaction of a hydroxide in the gel phase with a substance whose anion forms a sparingly soluble compound with a hydrolyzable metal, in an aqueous, 0.001-5.0 molar solution of this substance or in the gas phase. 2. The method according to claim 1, characterized by americium, antimony, tin, curium, germanium, hafnium, aluminum, chromium, Manganese, niobium, lead, plutonium, tantalum, thorium, titanium, uranium, vanadium, bismuth, rare earths, zircon, iron or mixtures of at least two of these elements as a hydrolyzable metal. 3. The method according to claim 1 or 2, characterized by implementation of the hydroxide in the gel phase with an aqueous solution of arsenic acid, hexacyanoiron (III) acid, hexacyanoiron (II) acid, Phosphoric acid, phosphorous acid, diphosphoric acid, selenous acid, sulfuric acid, oxalic acid or telluric acid Acid. 4. The method according to claim 1 or 2, characterized by implementation of the hydroxide in the gel phase with an aqueous solution of an alkali metal or ammonium hydrogen carbonate or hydrogen sulfide. 5. The method according to claim 1 or 2, characterized by 509835/1017 settling of the hydroxide in the gel phase with alkali metal resp. Ammonium antimonate (V), molybdate, sulfide, carbonate, vanadate (V) or tungstate (VI) together with nitric acid, Perchloric acid, hydrochloric acid or acetic acid. 6. The method according to claim 1 or 2, characterized by reacting the hydroxide in the gel phase with an aqueous one Solution of an alkaline earth metal hydroxide or a solution of an alkaline earth metal salt together with an aqueous solution of a Alkali metal or ammonium hydroxide. 7. The method according to claim 1 or 2, characterized by reacting the hydroxide in the gel phase with an aqueous one Solution of a complex compound of ammonia with one chosen from copper, the platinum metals, zinc and iron Substance. 8. The method according to claim 1 or 2, characterized by reacting the hydroxide in the gel phase with gaseous hydrogen halide, Hydrogen cyanide, sulfur dioxide, rhodanic acid, hydrogen selenium or hydrogen telluride. 509835/1 017