Process for Preparing Colloidal Solution of Antimony Pentoxide

Europaisches Patentamt

European Patent Office (jj) Publication number: 0134 708 B1 Office europeen des brevets

® EUROPEAN PATENT SPECIFICATION

(§) Date of publication of patent specification: 18.10.89 @ Int. CI.4: C 01 G 30/00, B 01 J 13/00, ~ C 09 K 21/00 (n) Application number: 84305426.3

(22) Date of filing: 09.08.84

(H) Process for preparing colloidal solution of antimony pentoxide.

(30) Priority: 16.08.83 JP 149358/83 (73) Proprietor: NISSAN CHEMICAL INDUSTRIES LTD. 3-7-1, Kanda Nishiki-cho (§) Date of publication of application: Chiyoda-ku Tokyo (JP) 20.03.85 Bulletin 85/12

Inventor: Watanabe, Yoshitane @ Publication of the grant of the patent: 3-5-1-91 1,Hirai 18.10.89 Bulletin 89/42 Edogawa-ku Tokyo (JP) Inventor: Suzuki, Keitaro c/o Nissan Kagaku Yatsu-Ryo (§) Designated Contracting States: 5-32-9, Yatsu Narashino-shi BEDE FRGB Chiba-ken (JP) Inventor: Teranishi, Masayuki 7-27-13, Takanedai (3) References cited: Funabashi-shi Chiba-ken (JP) EP-A-0025 246 DE-A-2 622 608 DE-A-2715 737 @ Representative: Wood, Anthony Charles et al GB-A-2126205 Urquhart-Dykes & Lord 91 Wimpole Street CD US-A-4348301 London W1M8AH (GB) oo o

^- CO

Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall CL be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been LU paid. (Art. 99(1) European patent convention). Courier Press, Leamington Spa, England. 1 EP 0 134 708 B1 2 Description monate to an acid treatment under the conditions as prescribed hereinlater to form a gel, and then Background of the invention peptizing the gel by use of an organic base. This invention relates to a process for preparing According to this invention, there is provided a a colloidal solution of antimony pentoxide. More 5 process for preparing an antimony pentoxide sol, particularly, it relates to a novel process for which comprises dispersing an alkali antimonate preparing a colloidal solution of antimony pen- in water, reacting the alkali antimonate with a toxide by obtaining an antimony pentoxide gel monovalent or divalent inorganic acid added in a from an alkali antimonate and an inorganic acid, stoichiometrical amount of 0.7 times to 5 times and then peptizing the gel by use of a base. io the amount of the alkali antimonate to form an The colloidal solution of antimony pentoxide antimony pentoxide gel, followed by separation (hereinafter referred to as "antimony pentoxide and water washing of the gel, dispersing said gel sol") is used as a flame retardant or the like for in water, and peptizing the thus dispersed gel by plastics, fibers, etc. Conventional processes for adding an organic amine or guanidine hydroxide preparing the antimony pentoxide sol are roughly 15 in such a manner that the stoichiometrical classified into an ion exchange method and a amount of base/Sb205 ranges from 0.03 to 1. Y hydrogen peroxide method. As the former ion exchange method, there may be mentioned a Brief description of the drawing method in which potassium antimonate is Figs. 1, 2 and 3 each show an electricon deionized (U.S. Patent 3,860,523), or a method in 20 microscopic photograph of antimony pentoxide which sodium antimonate is deionized (U.S. sol obtained in Examples 1, 3 and 6, respectively; Patent 4,110,247). The antimony pentoxide sols Fig. 4, a photograph of antimony pentoxide sol obtainable by this method have good dispersibil- prepared by an ion exchange method; and Fig. 5, ity as they are comprised of particles almost by a hydrogen peroxide method. Magnification: spherical in shape, and are characteristic in that 25 200,000 each. they can further be made higher in concentration. However, it is difficult according to this ion Description of the preferred embodiments exchange method to effect ion exchange when Alkali antimonate which is a starting material the concentration of antimony pentoxide exceeds used in this invention is represented by the 10%, Moreover, this method has a drawback that 30 general formula: it requires complicated operations such that sub- sequent operations for separation and regenera- M20 • Sb2Os • XH20, tion of ion exchange resins must be carried out. The latter hydrogen peroxide method is a method in which M represents an alkali metal such as in which antimony trioxide is oxidized by use of 35 sodium and potassium, and X=0 to 6. Sodium is hydrogen peroxide at a high temperature (see, preferred as the alkali metal. Particularly pre- USP 4,022,710; Japanese Unexamined Patent ferred is a hydrate of sodium antimonate Publication No. 21298/1977; U.S. Patents, 4,028,226 and 4,026,819). This method shows Na20 • Sb2Os • 6H20 (NaSb(OH)6; high productivity because it is possible to obtain 40 antimony pentoxide sols comprising about 30% 63 to 64% by weight of Sb205, 12 to 13% by antimony pentocide directly, but inadvantageous weight of Na20 and 23 to 24% by weight of H20). in that the viscosity increases when antimony The acid usable in this invention for the step of pentoxide exceeds 30%. Moreover, this method forming the antimony pentoxide gel by the reac- has drawbacks that colloidal particles of the sols 45 tion of an alkali antimonate with an acid includes are irregular in shape so that there is obtained monovalent or divalent inorganic acids such as only poor dispersibility and, because of strong hydrochloric acid, nitric acid, sulfuric acid and surface activity, poor compatibility with resin sulfamic acid. Phosphoric acid, which has acid emulsions and the like. strength almost equal to antimonic acid GB— A— 2126205 discloses a finding that a so (HSb(OH)6), is unavailable for obtaining the anti- hydrated metal oxide or hydroxide can be pep- mony pentoxide gels. Acids of weaker acid tized in water by adding a quaternary ammonium strength, such as formic acid, exalic acid, etc., are hydroxide. A preferred metal oxide is hydrous also unavailable for obtaining the desired anti- antimony (V) oxide. The extent of peptization can mony pentoxide gels. be sufficient for creation of a sol. 55 In the reaction of an alkali antimonate with the above acid in this invention, it is possible to use Summary of the invention the alkali antimonate in concentration of 2 to 35% In order to eliminate the above-mentioned by weight in terms of anhydrous antimony pen- drawbacks in the conventional processes for pre- toxide (Sb2Os) in the reaction mixture. In case the paring antimony pentoxide sols, the present 60 concentration is less than 2% by weight, the inventors have made intensive studies on the amount of antimony pentoxide gels produced preparation of antimony pentoxide sol composi- becomes too small to be desirable from economi- tion. As a result, they have found a novel process cal viewpoint. In case it is in excess of 35% by in which the desired antimony pentoxide sol is weight, the solid portion in the reaction mixture obtained by first subjecting a starting alkali anti- 65 reaches 50% or more and the reaction becomes

2 3 EP 0134 708 B1 4 heterogeneous. Preferable concentration ranges After dispersing the wet cake of the antimony from 6 to 25% by weight as the anhydrous pentoxide gels in water, antimony pentoxide sols antimony pentoxide. can be obtained by peptizing the gels under the In the reaction of alkali antimonate with the conditions prescribed below. above acid according to this invention, concen- 5 By the way, the antimony pentoxide gels can tration of the acid may be selected such that the not be peptized under the conditions prescribed stoichiometrical amount of acid/alkali antimonate below, if they are turned to a dry gel. ranges from 0.7 to 5, preferably, from 1 to 3. In The base usable in the step of peptizing the case the stoichiometrical amount is less than 0.7, antimony pentoxide gels according to this inven- it is impossible to obtain the desired antimony 10 tion may include amines such as triethanolamine, pentoxide gels even if reaction temperature and tripropanolamine, diethanolamine, mono- concentration of alkali antimonate are elevated. In ethanoiamine, N-ethylaminoethanolamine, etc; case it exceeds 5, the antimony pentoxide gels quaternary ammonium hydroxides such as tet- formed are peptized at the stage of water wash- raethanolammonium hydroxide, monomethyl- ing, whereby sols are washed away into a filtrate, 15 triethanolammonium hydroxide; and organic and thus the productivity becomes inferior. bases such as guanidine hydroxide, etc. Bases In the reaction of alkali antimonate with the such as sodium hydroxide, potassium hydroxide above acid according to this invention, reaction and ammonia are not suitable as the base since temperature may range from room temperature they, which are incorporated into the structure of to 100°C, and the reaction time available may 20 the antimony pentoxide, can only be peptized in range from 1 hourto 15 hours. In order to obtain part (see Comparative Examples). Addition of any antimony pentoxide sols of good shape, it is of these bases is effective in that the antimony preferred to employ the reaction temperature not pentoxide gels formed by the reaction are pep- higher than 50°C and the reaction time not longer tized, and, in addition, plays an important role in than 10 hours. When the reaction temperature is 25 that fine particles thereof are dehydrated and higher than 50°C and the reaction time exceeds 1 5 condensated to become colloidal particles of anti- hours, particles of the resultant antimony pentox- mony pentoxide nearly spherical in shape and 10 ide sols tends to become irregular in shape. to 100 nm in size. Fine colloids of antimony pentoxide formed by In this invention, the peptization may be carried the reaction of this invention are highly aggre- 30 out at a temperature ranging from room tempera- gated owing to the acid and its salt with alkali ture to 150°C. It is possible to carry out the metal present in the reaction system to form peptization in an autoclave, but is not economical. antimony pentoxide gels (usually particles of 3 It is preferred to carry out it at a temperature um or larger are formed), and immediately ranging from 50 to 100°C. Time required for sedimented in the reaction mixture. Accordingly, 35 completion of the peptization may vary depend- the gel slurry thus formed can be separated very ing on the kinds and amounts of the base and the easily by a pressure (or suction) filtration method, peptization temperature, but may range from 0.5 a centrifugal filtration method or the like. After to 20 hours. filtration, it becomes necessary to make washing The amount of the base required for the pepti- in order to remove coexisting acid and its alkali 40 zation according to this invention is such that the metal salt. In washing, it is possible that partial stoichiometrical amount of base/Sb205 ranges hydrolysis of antimony pentoxide is accelerated from 0.03 to 1.0, preferably, from 0.07 to 0.5. In because of its contact with a large quantity of case this stoichiometrical amount is less than water, or that there occurs partial peptization. 0.03, the peptization can not be achieved even if Therefore, in both the cases of the reduced 45 the peptization temperature is raised. In case it pressure filtration and the centrifugal filtration, exceeds 1.0, the peptization is carried out only washing must be carried out immediately by with so higher pH of sols that stability in storage pouring water in an amount of 1 time to 4 times is lowered when the resultant sols were made the amount of the reaction mixture. Amount of higher in concentration and, moreover, because antimony pentoxide which may be washed away 50 of an excessive amount of the base, it becomes into the filtrate by filtration and washing in the very difficult to dry the sols. According to this process of this invention is not more than 3% by invention, rate of the peptization can be sub- weight. stantially 100%. Wet cake of antimony pentoxide gel obtained According to this invention, it is possible to by the above filtration and washing has water 55 attain the peptization concentration (herein meant content of 30 to 40% by weight, and most part by concentration of colloidal solution or sol pro- thereof comprises water of crystallization. duced by peptization) ranging from 2 to 55% by X-ray diffraction patterns of this antimony pen- weight in terms of anhydrous antimony pentox- toxide gels are same as those of the hydrate of ide (Sb205). When the peptization concentration is antimony pentoxide (Sb205 • 4HzO), and X-ray 60 in a lower range of 2 to 30% by weight, sols may diffraction patterns for the starting alkali antimo- be concentrated by an evaporation method, aN nate are not observed. There can be recognized a ultrafiltration method, a reverse osmosis method residue of alkali metal in this antimony pentoxide or the like, whereby sols having higher concen- gels, and the molar ratio of M20/Sb203 ranges tration of 30 to 55% by weight are readily between 0.2 and 0.5. 65 obtained. In case the concentration is less than

3 5 EP 0134 708 B1 6 2% by weight, cost for the concentration steps Na20, 35.1% H20; molar ratio of Na20/Sb2Os becomes too high for the process to be economi- being 0.296) were added 300 ml of water, cal. In case it exceeds 55% by weight, viscosity of followed by further addition of 19 g of sols becomes higher undesirably. triethanolamine (stoichiometrical amount of The peptized antimony pentoxide sols obtained 5 amine/Sb2Os being 0.09), which were then heated by the process of this invention have pH ranging to 75°C to carry out peptization for 5 hours. There from 4.0 to 10.5, which can be readily made to be was observed no unpeptized product remained. 1.5 to 4 by allowing the sols to pass a column Resultant sol had specific gravity of 1.616, pH of packed with cation exchange resins. 5.78, viscosity of 9.3 c.p., 41.2% Sb205, 2.33% The process according to this invention 10 Na20, 540 ppm CI, and particle size of 20 to 50 described in the foregoing have advantageous nm; particles were substantially spherical in effects as follows: shape. An electron microscopic photograph of (1) Compared with the ion exchange method or this resultant sol is shown in Fig. 1. The above sol the hydrogen peroxide method which are conven- was stored for a month at 50°C, but there was no tional processes for preparing antimony pentox- 15 increase in the viscosity. ide sols, it is possible to readily obtain antimony pentoxide sols having higher concentration rang- Example 2 ing from 30 to 55% by weight. 720 g of sodium antimonate were dispersed in (2) In spite of Sb205 concentration of 30 to 55% 220 ml of water, to which added with stirring were by weight (specific gravity: 1.4 to 2.1), viscosity is 20 245 g of 35% hydrochloric acid. A mixture thus less than 15 c.p. undesirably since the colloidal obtained was heated to 65°C and reaction was particles are substantially spherical in shape, and carried out for 3.5 hours. In the reaction mixture, the stability in storage is also very good. Inciden- concentration of antimony pentoxide was 0.81% tally, the particle size is in the range of from 10 to and the stoichiometrical amount of hydrochloric 100 nm. 25 acid/sodium antimonate was 14.4. Thereafter, (3) Even though the concentration of Sb205 is as slurry of antimony pentoxide gel formed by the high as 30 to 55% by weight, it is possible to keep reaction was subjected to suction filtration, and pH stably not lower than 7 without remarkable then washed with water while pouring 500 ml of increase in the viscosity, by making post-addition water. To 750 g of a wet cake of antimony of bases such as ammonia, sodium hydroxide, 30 pentoxide gel were added 380 ml of water, triethanolamine and quarternary ammonium followed by further addition of 10 g of dieth- hydroxide. In the case of the antimony pentoxide anolamine with stirring, which were then heated sols according to the conventional preparation to 95°C to carry out peptization for 6 hours. methods, it was difficult because of increase in Concentration of antimony pentoxide at the stage viscosity to make the pH stably not lower than 7 35 of peptization was 40% and stoichiometrical even if ammonia or sodium hydroxide is added, amount of amine/Sb205 was 0.071. and also it is defective that the sols tend to turn Resultant sol had specific gravity of 1.606, pH of pale yellow. As a characteristic property, the 6.4, viscosity of 4.5 c.p., and particle size of 10 to alkaline sols prepared by the process according to 40 nm. this invention are free from gelation even when 40 mixed with emulsions of resins such as viny- Example 3 lidene chloride, acrylic resins, etc., and therefore 480 g of sodium antimonate were dispersed in have excellent compatibility. 2240 ml of water, to which added with stirring This invention will be described below in were 376 g of an aqueous solution of 40% sulfuric greater detail by Examples, by which the inven- 45 acid. A mixture thus obtained was heated to 37°C tion is not limited, however. and reaction was carried out for 3 hours. In the In the following Examples, "%" denotes "% by reaction mixture, concentration of antimony pen- weight" and sodium antimonates used have the toxide was 9.92%, concentration of sulfuric acid composition of 64% Sb20s, 12.5% Na20 and was 4.86%, and the stoichiometrical amount 23.5% H20. so (chemical equivalent) of sulfuric acid/sodium antimonate was 0.812. After completion of the reac- Example 1 tion, slurry of antimony pentoxide gel thus 600 g of sodium antimonate were dispersed in formed was subjected to suction filtration, and 2000 ml of water, to which added with stirring then washed with water while pouring 6000 ml of were 350 g of 35% hydrochloric acid. A mixture 55 water. At these stages of filtration and washing, thus obtained was heated to 40°C and reaction 2.2% of antimony pentoxide were washed away. was carried out for 4 hours. In the reaction A wet cake of antimony pentoxide gel thus mixture, concentration of antimony pentoxide obtained was in amount of 506 g, to which were was 12.9% and the stoichiometrical amount of added 2400 ml of water to disperse the wet cake, hydrochloric acid/sodium antimonate was 1.39. 60 followed by further addition of 13 g of Thereafter, slurry of antimony pentoxide gel triethanolamine, which were then heated to 75°C formed by the reaction was subjected to suction to carry out peptization for 4.5 hours with stirring. filtration, and then washed with water while Stoichiometrical amount of triethanolamine/ pouring 4000 ml of water. To 625 g of a wet cake Sb205 was 0.093. of antimony pentoxide gel (61.4% Sb2Os, 3.5% 65 Resultant peptized sol has antimony pentoxide

4 1 EP 0134 708 B1 ;oncentration of 10%, pH of 5.8, viscosity of 2.0 washed with water while pouring 4UUU ml ot :.p.; particles were nearly spherical in shape, and water. To 550 g of wet cake of the resultant also the particle distribution was small. An elec- antimony pentoxide gel were added 538 ml of :ron microscopic photograph of the sol obtained water, followed by further addition of 12g of lere is shown in Fig. 2. 5 diethanolamine, which were then heated to 80°C This sol was concentrated to 50% concentration to carry out peptization for 4 hours with stirring. Df antimony pentoxide by means of a rotary Concentration of antimony pentoxide at the stage svaporator at a liquid temperature of 60°C. Resul- of peptization was 30% and stoichiometrical :ant concentrated sol had specific gravity of 1 .91 5, amount of amine/Sb205 was 0.12. The pH of the dH of 6.3, viscosity of 8.5 c.p., and particle size of 10 peptized sol was 8.4. 30 to 60 nm. The peptized sol obtained was concentrated to This concentrated sol was allowed to stand for 50% concentration of antimony pentoxide by a month, but there was observed no increase in means of an evaporator and at 80°C. Resultant the viscosity of sol. There was also observed no concentrated sol had specific gravity of 1.89, pH change in the shape and size of particles by the is of 9.2, viscosity of 12.5 c.p., and particle size of 20 concentration. to 50 nm. Further, to 500 g of the above concentrated sol i/vere added 15 g of NaOH (solid) with stirring to Example 6 obtain sol having specific gravity of 1.926, pH of 250 g of sodium antimonate were dispersed in B.3, viscosity of 18 c.p., and 48.5% of Sb205. Then, 20 1550 ml of water, to which added with stirring 10 g of the sol thus obtained were added to 100 g were 200 g of 35% hydrochloric acid. A mixture of an emulsion of polyvinylidene chloride, but no thus obtained was heated to 25°C and reaction gelation of the sol was observed, and a was carried out for 8 hours. In the reaction homogeneous solution was obtained. mixture, concentration of antimony pentoxide 25 was 8.0%, and the stoichiometrical amount of Example 4 hydrochloric acid/sodium antimonate was 1.90. 1440 g of sodium antimonate were dispersed in After completion of the reaction, slurry of anti- 1640 ml of water, to which added with stirring mony pentoxide gel formed was subjected to were 680 g of 35% hydrochloric acid. A mixture centrifugal filtration, and then washed with water thus obtained was heated to 50°C and reaction 30 while pouring 4000 ml of water. A wet cake of was carried out for 3.5 hours. In the reaction antimony pentoxide gel thus obtained in amount mixture, concentration of antimony pentoxide of 260 g was then dispersed in 1730 ml of water, was 24.5%, concentration of hydrochloric acid followed by addition of 7.6 g of triethanolamine was 6.5%, and the stoichiometrical amount of with stirring to carry out the peptization at 80°C hydrochloric acid/sodium antimonate was 2.36. 35 for 6 hours. Thereafter, slurry of antimony pentoxide gel Resultant sol had antimony pentoxide concen- formed by the reaction was subjected to cen- tration of 8.0%, Na20 amount of 0.53%, trifugal filtration, and then washed with water stoichiometrical amount of Na20/Sb205 being while pouring 6000 ml of water. A wet cake of 0.35, CI amount of 50 ppm, pH of 5.2, and antimony pentoxide gel thus obtained was in 40 viscosity of 1.5 c.p. Also, the colloidal particles of amount of 1520 g. antimony pentoxide obtained were substantially To 600 g of wet cake of the resultant antimony spherical in shape and had particle size of 10 to 30 pentoxide gel were added 100 ml of water, nm. an electron microscopic photograph of this followed by further addition of 100 g of an sol obtained is shown in Fig. 3. aqueous solution of monoethyl- 45 This sol was concentrated to 50% concentration triethanolammonium hydroxide (35% as NR40H) of antimony pentoxide by ultrafiltration. The con- with stirring, which were then heated to 50°C for centrated sol had specific gravity of 1.88, pH of 1.5 hours to carry out the peptization. 5.87, viscosity of 9.5 c.p. Further, by allowing the Stoichiometrical amount of quaternary peptized sol to pass a cation exchange resin ammonium hydroxide/Sb205 was 0.19. Resultant so (Amberlite 120 B) packed in a column, obtained sol had specific gravity of 1 .80, pH of 9.6, viscosity was acidic antimony pentoxide sol of pH 2.5. of 14 c.p., 47% of Sb205, and particle size of 10 to Thereafter, to 1300 g (8% Sb2Os) of this sol were 40 nm. added 106 g of an aqueous solution of 10% sodium hydroxide to regulate the pH, and then Example 5 55 the sol thus treated was concentrated to 40% 480 g of sodium antimonate were dispersed in concentration of antimony pentoxide at 60°C by 2320 ml of water, to which added were 330 g of use of a rotary evaporator. As a result, obtained 60% cone, nitric acid with stirring. A mixture thus was sol having specific gravity of 1.62, pH 8.6, obtained was heated to 35°C and reaction was viscosity of 25 c.p., and having good stability in carried out for 4 hours. In the reaction mixture, eo storage. concentration of antimony pentoxide was 0.7%, and the stoichiometrical amount of nitric acid/ Example 7 sodium antimonate was 0.80. Thereafter, slurry of 720 g of sodium antimonate were dispersed in antimony pentoxide gel formed by the reaction 823 ml of water, to which added with stirring were was subjected to centrifugal filtration, and then 65 300 g of 35% hydrochloric acid. A mixture thus

5 9 EP 0134 708 B1 10 obtained was heated to 25°C and reaction was said sodium antimonate is a hydrate of sodium carried out for 4 hours. In the reaction mixture, antimonate. concentration of antimony pentoxide was 25% 4. The process according to Claim 1, wherein and the stoichiometrical amount of hydrochloric said inorganic acid is selected from the group acid/sodium antimonate was 2.03. Thereafter, 5 consisting of hydrochloric acid, nitric acid, sul- slurry of antimony pentoxide gel formed after furic acid and sulfamic acid. completion of the reaction was subjected to cen- 5. The process according to Claim 1, wherein trifugal filtration, and then washed with water concentration of said alkali antimonate in the while pouring 4000 ml of water. reaction mixture is 2 to 35% by weight as anhydr- Resultant 765 g of antimony pentoxide gel wet 10 ous antimony pentoxide. cake (60.2% Sb20s) were dispersed in 187 ml of 6. The process according to Claim 5, wherein water, followed by addition of 88 g of concentration of said alkali antimonate in the triethanolamine with stirring to carry out peptiza- reaction mixture is 6 to 25% by weight as anhydr- tion at 40°C for 2 hours. Stoichiometrical amount ous antimony pentoxide. of triethanolamine/Sb205 was 0.12. 75 7. The process according to Claim 1, wherein Resultant antimony pentoxide sol had specific the stoichiometrical amount of the acid/alkali gravity of 1.90, pH of 8.0, viscosity of 9.5 c.p., antimonate ranges from 1 to 3. antimony pentoxide concentration of 49.0%, and 8. The process according to Claim 1, wherein particle size of 10 to 40 nm. the" reaction to form said antimony pentoxide gel 20 is carried out at a temperature ranging from a Comparative example 1 room temperature to 100°C and for 1 hour to 15 480 g of sodium antimonate were dispersed in hours. 2360 ml of water, to which added were 60 g of 9. The process according to Claim 8, wherein 89% formic acid with stirring, and thereafter the the reaction to form said antimony pentoxide gel mixture was heated to 75°C and reaction was 25 is carried out at a temperature ranging from a carried out for 5 hours. However, no antimony room temperature to 50°C and for 1 hour to 10 pentoxide gel was formed. In the reaction mix- hours. ture, concentration of antimony pentoxide was 10. The process according to Claim 1, wherein 10.2%, concentration of formic acid was 4.75%, said organic base is an amine. and stoichiometrical amount of formic acid/ 30 11. The process according to Claim 10, wherein sodium antimonate was 1.60. said amine is selected from the group consisting of triethanolamine trepropanolamine,' dieth- Comparative example 2 anolamine, monoethanolamine and N-ethy- 480 g of sodium antimonate were dispersed in laminoethanolamine. 2240 ml of water, to which added were 320 g of 35 12. The process according to Claim 1, wherein 35% hydrochloric acid, and then reaction was said quaternary ammonium hydroxide is selected carried out at 40°C for 4 hours. After completion of from the group consisting of tet- the reaction, antimony pentoxide gel slurry thus raethanolammonium hydroxide and mono- formed was subjected to centrifugal filtration, methyltriethanolammonium hydroxide. followed by pouring therein of 4000 ml of waterto 40 13. The process according to Claim 1, wherein carry out washing. Resultant 500 g of antimony said organic amine or guanidine hydroxide is pentoxide gel wet cake were then dispersed in used for the peptization in a stoichiometrical 2515 ml of water, to which were added 60 g of amount of organic/Sb205 ranging from 0.07 to 0.5. 10% NaOH with stirring to carry out peptization at 14. The process according to Claim 1, wherein 90°C for 25 hours. Rate of the peptization was 45 the peptization is carried out at a temperature about 50%. ranging from a room temperature to 150°C and for 0.5 hour to 20 hours. Claims 15. The process according to Claim 14, wherein said temperature ranges from 50 to 150°C. 1. A process for preparing an antimony pentox- so 16. The process according to Claim 14, wherein ide sol, which comprises dispersing an alkali the amount of antimony pentoxide gel at the antimonate in water, reacting the alkali antimo- stage of peptization ranges from 2 to 55% by nate with a monovalent or divalent inorganic acid weight. added in a stoichiometrical amount of 0.7 times to 5 times the amount of the alkali antimonate to 55 Patentanspriiche form an antimony pentoxide gel, followed by separation and water washing of the gel, dispers- 1. Verfahren zur Herstellung eines Antimonpen- ing said gel in water, and peptizing the thus toxidsols, das die Schritte aufweist, ein Alkalianti- dispersed gel by adding in water an organic monat in Wasser zu dispergieren, das Alkalianti- amine or guanidine hydroxide in such a manner 60 monat mit einer mono- oder bivalenten anorgani- that the stoichiometrical amount of base/Sb205 schen Saure reagieren zu lassen, die zur Bildung ranges from 0.03 to 1 . eines Antimonpentoxidgels in einer stochiometri- 2. The process according to Claim 1, wherein schen Menge von 0,7- bis 5-mal der Menge des said alkali antimonate is sodium antimonate. Alkaliantimonats zugegeben wird, gefolgt von 3. The process according to Claim 2, wherein 65 Trennung und Wasserwasche des Gels, das Gel in 11 EP 0 134 708 B1 12 Wasser zu dispergieren, und das so dispergierte moniate alcalin avec un acide inorganique mono- Gel durch Zugabe in Wasser von einem organi- valent ou divalent ajoute en quantite stoechiome- schen Amin- Oder Guanidinhydroxid zu peptisie- trique de 0,7 a 5 fois la quantite d'antimoniate ren, so dalS die stochiometrische Menge von alcalin pour former un gel de pentoxyde d'anti- Basis/Sb205 in einem Bereich von 0,03 bis 1 liegt. 5 moine, puis a separer ce gel et le laver a I'eau, 2. Verfahren nach Anspruch 1, worin das Alka- disperser ce gel dans I'eau et peptiser le gel ainsi liantimonat ein Natriumantimonat ist. disperse en ajoutant une amine organique ou de 3. Verfahren nach Anspruch 2, worin das I'hydroxyde de guanidine de maniere a ce que la Natriumantimonat ein Hydrat des Natriumanti- proportion stoechiometrique base/Sb205 soit de monats ist. w I'ordre de 0,03 a 1. 4. Verfahren nach Anspruch 1, worin die anor- 2. Procede selon la revendication 1, ou ledit ganische Saure aus der Gruppe, die aus Chlor- antimoniate alcalin est I'antimoniate de sodium. wasserstoffsaure, Salpetersaure, Schwefelsaure 3. Procede selon la revendication 2, ou ledit und Sulfamidsaure besteht, ausgewahlt ist. antimoniate est un hydrate de I'antimoniate de 5. Verfahren nach Anspruch 1, worin die Kon- 15 sodium. zentration des Alkaliantimonats in dem Reak- 4. Procede selon la revendication 1, ou ledit tionsgemisch 2 bis 35 Gew.% als nichtwalSriges acide inorganique est choisi parmi: acide chlorhy- Antimonpentoxid betragt. drique, acide nitrique, acide sulfurique et acide 6. Verfahren nach Anspruch 5, worin die Kon- sulfamique. zentration das Alkaliantimonats in dem Reak- 20 5. Procede selon la revendication 1, ou la tionsgemisch 6 bis 25 Gew.% als nichtwalSriges concentration dudit antimoniate alcalin dans le Antimonpentoxid betragt. melange reactionnel est de 2 a 35% en poids de 7. Verfahren nach Anspruch 1, worin der sto- pentoxyde d'antimoine anhydre. chiometrische Betrag der Saure/Alkaliantimonat 6. Procede selon la revendication 5, ou la im Bereich von 1 bis 3 liegt. 25 concentration dudit antimoniate alcalin dans le 8. Verfahren nach Anspruch 1, worin die Reak- melange reactionnel est de 6 a 25% en poids de tion zur Bildung des Antimonpentoxidgels 1 bis pentoxyde d'antimoine anhydre. 15 Stunden lang bei einer Temperatur im Bereich 7. Procede selon la revendication 1, ou la von Raumtemperatur bis 100° durchgefuhrt wird. quantite stoechiometrique acide/antimoniate 9. Verfahren nach Anspruch 8, worin die Reak- 30 alcalin se situe entre 1 et 3. tion zur Bildung des Antimonpentoxidgels 1 bis 8. Procede selon la revendication 1, ou la 10 Stunden lang bei einer Temperatur im Bereich reaction pour former ledit gel de pentoxyde d'an- von Zimmertemperatur bis 50° durchgefuhrt wird. timoine est effectuee a une temperature allant de 10. Verfahren nach Anspruch 1, worin die orga- la temperature ambiante a 100°C et durant 1 nische Base ein Amin ist. 35 heure a 15 heures. 11. Verfahren nach Anspruch 10, worin das 9. Procede selon la revendication 8, ou la Amin aus der Gruppe ausgewahlt ist, die aus reaction pour former ledit gel de pentoxyde d'an- Triathanoiamin, Tripropanolamin, Diathanola- timoine est effectuee a une temperature allant de min, Monoathanolamin und N-Athylaminoatha- la temperature ambiante a 50°C et durant 1 heure nolamin besteht. 40 a 10 heures. 12. Verfahren nach Anspruch 1, worin das 10. Procede selon la revendication 1, ou ladite quaternare Ammoniumhydroxid aus der Gruppe base organique est une amine. ausgewahlt ist, die aus Tetraathanolammonium- 11. Procede selon la revendication 10, ou ladite hydroxid und Momoethyltriathanolammonium- amine est choisie parmi: triethanolamine, tripro- hydroxid besteht. 45 panolamine, diethanolamine, monoethanolamine 13. Verfahren nach Anspruch 1, worin das et N-ethylaminoethanolamine. organische Amin- oder Guanidinhydroxid in 12. Procede selon la revendication 1, oCi ledit einem stochiometrischen Betrag von organischer hydroxyde d'ammonium quaternaire est choisi Base/Sb2Os, der im Bereich von 0,07 bis 0,5 liegt, parmi: hydroxyde de tetraethanolammonium et fur die Peptisierung verwendet wird. so hydroxyde de monomethyltriethanolammonium. 14. Verfahren nach Anspruch 1, worin die Pepti- 13. Procede selon la revendication 1, ou la dite sierung 0,5 bis 20 Stunden lang bei einer Tempe- amine organique ou ledit hydroxyde de guanidine ratur im Bereich von Zimmertemperatur bis 150°C est utilise pour la peptisation en une proportion durchgefuhrt wird. stoechiometrique compose organique/Sb205 de 15. Verfahren nach Anspruch 14, worin die 55 0,07 a 0,5. Temperatur im Bereich von 50 bis 150°C liegt. 14. Procede selon la revendication 1, ou la 16. Verfahren nach Anspruch 14, worin die peptisation est effectuee a une temperature allant Menge des Antimonpentoxidgels im Stadium der de la temperature ambiante a 150°C et durant 0,5 Peptisierung im Bereich von 2 bis 55 Gew.% liegt. heure a 20 heures. 60 15. Procede selon la revendication 14, ou ladite Revendications temperature va de 50 a 150°C. 16. Procede selon la revendication 14, ou la 1. Procede de preparation d'un sol de pen- quantite de gel de pentoxyde d'antimoine lors du toxyde d'antimoine, qui consiste a disperser un stage de peptisation est de I'ordre de 2 a 55% en antimoniate alcalin dans I'eau, a faire reagir I'anti- 65 poids.

7 EP 0 134 708 B1

F I G.l

FI G.2

1 EP 0 134 708 B1

FI G.3

FI G.4 EP 0 134 708 B1

F I G,5