PL218290B1 - Nanometric amorphous ammonium-aluminum phosphate, anhydrous or hydrated, and process for the preparation of the nanometric amorphous ammonium-aluminum phosphate, anhydrous or hydrated - Google Patents

Description

The subject of the invention is nanometric amorphous aluminum ammonium phosphate anhydrous or hydrated and a method of obtaining nanometric amorphous anhydrous or hydrated aluminum ammonium phosphate.

80% of phosphorus compounds are used in the production of mineral fertilizers, 12% in the production of detergents, 5% of feed additives, and only 3% in other sectors of the economy. Other applications of phosphorus compounds include their use in the production of glass and ceramics, baking powders, water treatment agents, wood impregnation, food stabilizing additives, pigments, flame retardants and anti-corrosion agents, among others. Until recently, the most commonly used pigments with good anti-corrosion properties were red lead (a mixture of lead (II) and (IV) oxides) and zinc chromate (VI). For ecological reasons, these pigments are being phased out. Other pigments that provide anti-corrosive properties to the coatings are: borates, molybdates, ferrites, zinc dust and phosphates. Phosphates are a significant group of environmentally friendly anti-corrosion pigments. They are divided into pigments of the 1st, 2nd and 3rd generation. Among the 1st generation phosphate pigments, zinc phosphate is the most important. However, it is believed that its anti-corrosion properties are inferior to that of zinc chromate (VI). It was found that the introduction of, inter alia, a molybdenum anion has a positive effect on increasing the effectiveness of phosphate pigments. Zinc and strontium phosphorates have proved to be an effective anti-corrosion pigment in alkyd paints. It has been shown that 2nd generation phosphates [zinc and aluminum phosphate, zinc and iron (II) phosphate, zinc phosphoromolybdate] in solvent and water-soluble paints, used in an acidic environment, are characterized by high inhibiting properties of corrosion processes, similar to zinc chromate (VI). The anticorrosive properties of zinc phosphate, zinc phosphoromolybdate and zinc and calcium phosphoromolybdate in epoxy coatings were compared. The effectiveness of phosphate pigments containing Mg and Zn, Al and Zn, Mg and Ca and Zn as well as Al and Ca and Zn, and only Zn in alkyd melamine coatings, has been described. Aluminum phosphate is also used as an anti-corrosion pigment. In addition, it is used as a catalyst, catalyst support, as a high-temperature binding material, raw material for the production of ceramic materials, optical glasses and as a sorption material in medicine. Aluminumphosphate zeolites are also of significant use. Depending on the applications, aluminum phosphates must have the appropriate properties. In turn, ammonium phosphates and polyphosphates as well as melamine phosphate are used as flame retardants in plastics and fire retardant coatings. The gaseous products of the decomposition of phosphorus-containing compounds are considered to be the most effective inhibitors of gas-phase combustion. It is preferable to use compounds containing both phosphorus and nitrogen. Research is being carried out on the simultaneous use of a mixture of ammonium polyphosphates and aluminum hydroxide as flame retardants for plastics.

US Patent 2,550,490 describes a method of producing crystalline, hydrated aluminum ammonium, aluminum potassium and aluminum sodium hydrogen phosphates from phosphoric acid, sodium, potassium or ammonium hydroxide or carbonate and an aluminum-containing compound. The product obtained was washed with a methanol-water solution and with methanol to remove free phosphoric acid and dried at 70 ° C. Hydrated crystalline aluminum and ammonium hydrogen phosphate NH4Al3H14 (PO4) 8 x 4H2O with a molar ratio of NH4 ⁺ : Al ³⁺ : PO4 ^3- equal to 0.125: 0.375: 1 is obtained at boiling temperature from a reaction mixture with a high salt concentration of 78% by mass and hydrated crystalline aluminum ammonium hydroxyphosphate (NH4) 5Al6 (OH) 5 (PO4) 6 x 12H2O with a molar ratio of NH4 ⁺ : Al ³⁺ : PO4 ^3- equal to 0.83: 1: 1, which is obtained by neutralization of aluminum and ammonium hydrogen phosphate NH4Al3H14 (PO4) 8 x 4H2O. From US 4,956,172, crystalline aluminum and ammonium hydroxyphosphate NH4Al2OH (PO4) 2 x 2H2O with a molar ratio of NH4 ⁺ : Al ³⁺ : PO4 ³ equal to

0.5: 1: 1 and a particle diameter of 1 - 20 µm, which is obtained at a temperature of 125 - 250 ° C from a reaction mixture with a low salt concentration - 18% by mass containing aluminum hydroxide and ammonium dihydrogen or monohydrogen phosphate. US Patent 3,348,910 discloses a method for the preparation of ammonium magnesium phosphate monohydrate by reaction of ammonium dihydrogen phosphate and a water-insoluble magnesium compound in an aqueous suspension with a pH of 4.6 to 7.2 at a temperature of 80 to 100 ° C.

Commonly used anti-corrosive pigments are in the form of powders with various micrometric grain sizes. Literature reports on the study of coatings with nanoparticles

With anti-corrosion pigments (zinc phosphates), they clearly indicate that the reduced grain size of these pigments significantly affects the effectiveness of preventing and inhibiting the corrosion processes of steel and iron substrates. This is probably due to the larger specific surface of the powder with nanometric fragmentation, lower tendency for its sedimentation in the paint layer during the formation of the coating and better penetration of pigment particles into the substrate micro-inequalities (i.e. to places that may constitute corrosion centers). Classic reinforcing fillers (including Al2O3, SiO2) also show higher effectiveness in the nanoparticle form than in the case of microparticle grinding. Literature reports also show that the use of nanoparticle flame retardants significantly reduces the rate of heat release, flame spread and the amount of volatile products released during the burning of plastics, as compared to the use of microparticles.

The essence of the invention is the anhydrous or hydrated nanometric amorphous aluminum ammonium phosphate of formula Al ( _nx ) (NH ₄ ) ₃ ( _2x-1 ) H ₃ ( _1-X ) (PO ₄ ) ( _ny ) (OH) ₃ ( _1-y ), where 0 <x, y <1, n> 1. Is characterized by a solubility in water of from 0.1 to 0.6 g in 100 g of water, an oil absorption from 70 to 120 g / 100 g, ₂ BET surface area of 100 to 400 m ² / g and a particle size of from 200 to 1000 nm.

The method for the production of anhydrous or hydrated nanometric amorphous ammonium aluminum phosphate according to the invention, which consists in adding an aluminum salt solution to the ammonium phosphate solution while stirring, characterized in that an aluminum salt solution is added to the ammonium phosphate solution with stirring over time to 30 minutes. Then, after adding the total amount of the aluminum salt, the solution is stirred for at least 20 minutes, then the precipitate is separated by filtration from the mother liquor, washed three times with a liquid to solid ratio of 3: 1. The first two washes are carried out with water, the last with water or methanol solution, and the obtained precipitate is dried at 70 ° C for 3 hours. The molar ratio of Al ³⁺ to NH4 ⁺ to PO4 ^3- in the reaction mixture is 0.66: (1-3): 1, the total salt concentration is 30-60% by weight, the process temperature is 15-60 ° C, the pH of the mixture reaction value is 4-8. The ammonium phosphate solution is prepared by neutralizing phosphoric acid with ammonia or ammonia water, or by dissolving ammonium dihydrogen phosphate and / or ammonium phosphate monohydrate and / or ammonium phosphate in water. The aluminum salt solution is prepared by dissolving anhydrous or hydrated aluminum sulphate and / or anhydrous or hydrated aluminum nitrate and / or anhydrous or hydrated aluminum chloride in water.

Aluminum ammonium phosphate, according to the invention, due to its properties, can be used, inter alia, as an anti-corrosion or flame-retardant agent.

Example I ₃

9.1 g of ammonium dihydrogen phosphate are dissolved in 21.20 cm ^{3 of} water at room temperature. ₃

9.4 g of aluminum chloride are dissolved in 21.9 cm ^{3 of} water at room temperature. The aluminum chloride solution is metered into the ammonium dihydrogen phosphate solution very quickly with continuous stirring and the reaction mixture is brought to pH 6. The temperature and pH of the reaction mixture are kept constant throughout the process. After the addition of the total amount of aluminum chloride, the solution is stirred for 30 minutes, and then 38.2 g of the precipitate formed is separated from the mother liquor from the reaction mixture by filtration. The sediment is washed three times with water maintaining the mass ratio of water to sediment as 3: 1. The washed precipitate was dried at 70 ° C for 3 hours. Receives

12.8 g of amorphous aluminum ammonium phosphate containing 11.12 wt.% Al, 4.35 wt.% NH3, 32.44 wt.% P2O5 with the properties given in the table.

Example II ₃

10.0 g of ammonium dihydrogen phosphate are dissolved in 10.0 cm ^{3 of} water at room temperature. ₃

19.2 g of aluminum sulphate are dissolved in 19.2 cm ^{3 of} water at room temperature. The aluminum sulphate solution is dosed very rapidly to the ammonium dihydrogen phosphate solution with constant stirring and the reaction mixture is brought to pH 4. The temperature and pH of the reaction mixture are kept constant throughout the process. After the addition of the total amount of aluminum sulfate, the solution is stirred for 30 minutes, and then 48.9 g of the precipitate formed are separated from the mother liquor from the reaction mixture by filtration. The sediment is washed three times with water maintaining the mass ratio of water to sediment as 3: 1. The washed precipitate was dried at 70 ° C for 3 hours. 17.3 g of amorphous aluminum ammonium hydroxyphosphate were obtained, containing 11.52% by mass of Al, 3.33% by mass of NH3, 36.75% by mass of P2O5 with the properties given in the table.

PL 218 290 B1

Example III ₃

10.8 g of ammonium monohydrogen phosphate was dissolved in 16.3 cm ³ of water at the peace _three inputs. 18.0 g of aluminum sulphate is dissolved in 27.0 cm ^{3 of} water at room temperature. The aluminum sulphate solution is dosed very quickly to the ammonium monohydrogen phosphate solution with constant stirring and the reaction mixture is brought to pH 8. The temperature and pH of the reaction mixture are kept constant throughout the process. After the addition of the total amount of aluminum sulfate, the solution is stirred for 30 minutes, and then 50.9 g of a precipitate are separated from the reaction mixture by filtration from the mother liquor. The sediment is washed three times with water maintaining the mass ratio of water to sediment as 3: 1. The washed precipitate was dried at 70 ° C for 3 hours. 18.4 g of amorphous aluminum ammonium hydroxyphosphate were obtained, containing 11.08% by mass of Al, 5.02% by mass of NH3 and 16.0% by mass of P2O5 with the properties given in the table.

Example IV ₃

11.5 g of ammonium phosphate are dissolved in 27.0 cm ^{3 of} water at room temperature. 12.5 g ₃ of aluminum sulphate are dissolved in 29.3 cm ^{3 of} water at room temperature. The aluminum sulphate solution is metered into the ammonium phosphate solution over 30 minutes with continuous agitation and the reaction mixture is adjusted to pH 4. The temperature and pH of the reaction mixture are kept constant throughout the process. After adding the total amount of aluminum sulfate, the solution is stirred for 20 minutes and then 44.9 g of the precipitate are separated from the reaction mixture by filtration from the mother liquor. The sediment is washed three times with water maintaining the mass ratio of water to sediment as 3: 1. The washed precipitate was dried at 70 ° C for 3 hours. 11.2 g of amorphous aluminum ammonium hydroxyphosphate were obtained, containing 11.52% by weight of Al, 1.70% by weight of NH3, 18.55% by weight of P2O5 with the properties given in the table.

Example V ₃ g of ammonium phosphate monohydrate are dissolved in 10.0 cm ^{3 of} water and heated to a temperature of ₃

60 ° C. 25 g of aluminum sulphate is dissolved in 16.7 cm ^{3 of} water and heated to 60 ° C. The aluminum sulphate solution is metered into the ammonium monohydrogen phosphate solution over 10 minutes with constant agitation, and the reaction mixture is brought to pH 6. The temperature and pH of the reaction mixture are kept constant throughout the process. After the total amount of aluminum sulfate has been added, the solution is stirred for 30 minutes and then separated from the reaction mixture by filtration

57.4 g of a precipitate from the mother liquor. The sediment is washed three times with water maintaining the mass ratio of water to sediment as 3: 1. The washed precipitate was dried at 70 ° C for 3 hours. 15.4 g of amorphous aluminum ammonium hydroxyphosphate were obtained, containing 13.62% by mass of Al, 2.78% by mass of NH3, 39.05% by mass of P2O5 with the properties given in the table.

Example VI ₃

11.4 g of ammonium phosphate are dissolved in 26.5 cm ^{3 of} water at room temperature. 14.1 g ₃ of aluminum nitrate are dissolved in 32.8 cm ^{3 of} water at room temperature. An aluminum nitrate solution is metered into the ammonium phosphate solution over a period of 10 minutes with constant stirring, and the reaction mixture is adjusted to pH 6. The temperature and pH of the reaction mixture are kept constant throughout the process. After the addition of the total amount of aluminum nitrate, the solution is stirred for 30 minutes, and then 38.7 g of the precipitate is separated from the mother liquor from the reaction mixture by filtration. The sediment is washed three times with water maintaining the mass ratio of water to sediment as 3: 1. The washed precipitate was dried at 70 ° C for 3 hours. Receives

11.8 g of amorphous aluminum ammonium hydroxyphosphate containing 9.2 wt% Al, 3.3 wt% NH3, 23.7 wt% P2O5 with the properties given in the table.

T a b e l a

Solubility g / 100 g of water Oil number g / 100 g Specific BET surface area m ² / g Average grain diameter nm Example I 0.58 101 203 990 Example II 0.31 87 166 500 Example III 0.20 89 148 440 Example IV 0.28 91 102 290 Example V 0.10 95 161 480 Example VI 0.15 80 130 380

PL 218 290 B1

Claims (4)

1. The amorphous nanoscale ammonium phosphate anhydrous or hydrated alumina of the formula Al (nx), (NH4) 3 (2x-i) H3 _(1-x) (PO4) (ny) (OH) 3 ₍₁ y t), where 0 <x, y <1, n> 1, with a water solubility from 0.1 to 0.6 g in 100 g of water, an oil number from 70 to 120 g / 100 g, with a BET specific surface area from 100 to ₂ 400 m ² / g and a particle size of 200 to 1000 nm. 2. A method for the production of anhydrous or hydrated nanometric amorphous ammonium aluminum phosphate, which consists in adding an aluminum salt solution to the ammonium phosphate solution while stirring, characterized in that an aluminum salt solution is added to the ammonium phosphate solution while stirring for up to 30 minutes, then, after mixing the reagents for at least 20 minutes from the moment of adding the total amount of aluminum salt, the precipitate is separated by filtration from the mother liquor, washed three times, with a liquid-to-solid ratio of 3: 1, the first two washes with water and the latter with water or methanol solution, and the obtained precipitate was dried at 70 ° C for 3 hours, the molar ratio of Al ³⁺ to NH4 ⁺ 3o PO4 ^3- in the reaction mixture is 0.66: (1-3): 1, the total salt concentration is 30-60% by weight, the process temperature is 15-60 ° C, the pH of the reaction mixture is 4-8. 3. The method according to p. A process as claimed in claim 6, characterized in that the ammonium phosphate solution is prepared by neutralizing phosphoric acid with ammonia or ammonia water or by dissolving ammonium dihydrogen phosphate and / or ammonium phosphate monohydrogen phosphate and / or ammonium phosphate in water. 4. The method according to p. The process of claim 6, wherein the aluminum salt solution is prepared by dissolving anhydrous or hydrated aluminum sulphate and / or anhydrous or hydrated aluminum nitrate and / or anhydrous or hydrated aluminum chloride in water.