Method of producing anticorrosive pigment - chromium phosphate

FIELD: chemistry.

SUBSTANCE: chromium phosphate is obtained in a reactor by dissolving chromium trioxide in water. Orthophosphoric acid and a stabilising additive - ethanol - are then added. A strong reducing agent - aqueous hydrazine-hydrate solution - is slowly added to the obtained mixture of chromic acid, orthophosphoric acid and ethanol in an amount which enables formation and maturation of chromium phosphate particles, suspension pH of 4-7 and concentration of chromium phosphate of 50-100 g/cm. The end product is then filtered and dried. The filtrate is returned to preparation of the mixture of chromium trioxide, orthophosphoric acid and ethanol.

EFFECT: invention simplifies the technique and completely prevents formation of waste water.

1 tbl, 6 ex

 

The invention relates to methods of producing anti-corrosion pigments - phosphates of various metals used in primers, compositions, paint and varnish materials to protect various metals and alloys from corrosion.

A method of obtaining chromium phosphate, representing the average crystalline salt of orthophosphoric acid CrPO4·nH2O (Belenky E.F., Riskin IV Chemistry and technology of pigments. The "Chemistry"publishing house, Leningrad, 1974, p.447-449), which consists in the recovery of hexavalent chromium to trivalent of bichromate or chromate sodium in the presence of phosphoric acid. As reductants using sodium sulfite or sodium thiosulfate. In the process of obtaining chromium phosphate produce large quantities of water-soluble salts of Na2S04in the first case - 2 mol of phosphate chromium 4 mol of sodium sulfate; in the second case - to 8 moles of phosphate chromium 11 moles of sodium sulfate.

The disadvantages of this method are the formation of large quantities of wastewater in the form of an aqueous solution of Na2SO4and complex technological scheme of production of phosphate of chromium.

The technical result of the proposed method is the complete elimination of sewage and simplification of the technological scheme of production.

The technical result is achieved by the fact that re is ctor consistently deliver the water, chromic anhydride, phosphoric acid and (1-5) wt.% ethanol to the weight of the final product and the resulting mixture of chromic and phosphoric acids and ethanol slowly poured the strong reducing agent is an aqueous solution of hydrazine hydrate in an amount to provide education and aging of particles of chromium phosphate and the final pH of the suspension within 4-7 and phosphate concentration of chromium in the range of 50-100 g/DM3with subsequent filtering, returning the filtrate to the reactor in the preparation of the initial mixture of chromic and phosphoric acids and ethanol, as well as chromium reagent use chromic anhydride.

Comparative analysis of the claimed invention with the prototype shows that the inventive method differs from the known fact that as the chromium reagent is used chromic anhydride, as a reducing agent is an aqueous solution of hydrazine hydrate, and the regulator - moderator oxidation of hydrazine - hydrate oxygen at the stage of synthesis and dispersant particles of chromium phosphate at the stage of drying and the addition of ethanol (ethyl alcohol). These differences provide the phosphate of chromium in one device-the reactor and the complete elimination of wastewater. Thus, the claimed method meets the criteria of "novelty".

The presence of the criterion of "inventive the level" the authors acknowledge the fact, what is known from the patent and scientific literature reductants instrumental in obtaining the trivalent chromium from hexavalent, however, this process can be delayed for many hours, leads to the formation of wastewater and complicates the technological scheme of production of phosphate of chromium.

Examples of specific performance.

Example 1.

5 g of chromic anhydride dissolved in 75 cm3water. To the obtained solution of chromic acid, add 3 cm3orthophosphoric acid with a density of 1,572 g/cm3diluted in 10 cm3water and 0.13 cm3100%ethanol, which corresponds to 1 wt.% to the weight of the chromium phosphate. To the resulting mixture of chromic and phosphoric acids and ethanol under stirring slowly poured 14,3 cm3solution of hydrazine hydrate with a concentration of 10 wt.% N2H4. At the end of the feed solution of hydrazine - hydrate system is stirred for 1 h for the formation and aging of the pigment particles, after which the suspension was filtered and dried pasta. The final pH of the suspension is equal to 5.5. The filtrate is transparent and contains 0.004 g/DM3CrO3. The quality of the resulting pigment represented in the table.

Example 2.

5 g CrO3dissolve in 50 cm3water. To the obtained solution of chromic acid, add 3 cm3water and 0.39 cm3100%ethanol, which corresponds to 3 the AC.% to the weight of the chromium phosphate. To the resulting mixture of chromic and phosphoric acids and ethanol under stirring slowly poured 14 cm3aqueous solution of hydrazine hydrate with a concentration of 11 wt.% N2H4. At the end of the feed solution of hydrazine - hydrate system is stirred for 1 h for the formation and aging of the pigment particles, after which the suspension was filtered and dried pasta. The final pH of the suspension is equal to 6.0. The filtrate is transparent and contains 0.001 g/DM3CrO3. The quality of the resulting phosphate chromium are presented in the table.

Example 3 (control).

Synthesis is carried out analogously to examples 1 and 2, only a mixture of chromic and phosphoric acids add to 0.65 cm 100%ethanol, which is 5 wt.% to the weight of the chromium phosphate. To the resulting mixture of chromic and phosphoric acids and ethanol under stirring slowly poured 13.8 cm3aqueous solution of hydrazine hydrate with a concentration of 12 wt.% N2H4. At the end of the feed solution of hydrazine - hydrate system is stirred for 1 h for the formation and aging of the pigment particles, after which the suspension was filtered and dried pasta. The final pH value of the suspension is equal to 7.0. The filtrate is transparent and contains 0.0005 g/DM3CrO3. The quality of the resulting phosphate are presented in the table.

Example 4 (control).

Synthesis is carried out analogously to examples 1 and 2, tolchok a mixture of chromic and phosphoric acids add 1,04 cm 3100%ethanol, which is 8 wt.% to the weight of the chromium phosphate. To the resulting mixture of chromic and phosphoric acids and ethanol under stirring slowly poured 11.5 cm3aqueous solution of hydrazine hydrate with a concentration of 11 wt.% N2H4. At the end of the feed solution of hydrazine - hydrate system is stirred for 1 h for the formation and aging of the pigment particles, after which the suspension was filtered and dried pasta. The final pH value of the suspension is equal to 4.0. The filtrate is transparent and contains 0.05 g/DM3CrO3. The quality of the resulting phosphate are presented in the table.

Example 5 (control).

Synthesis is carried out analogously to examples 1 and 2, only a mixture of chromic and phosphoric acids add 1.3 cm 100%ethanol, which is 10 wt.% to the weight of the chromium phosphate. To the resulting mixture of chromic and phosphoric acids and ethanol under stirring slowly poured 10 cm3aqueous solution of hydrazine hydrate with a concentration of 11 wt.% N2H4. At the end of the feed solution of hydrazine - hydrate system is stirred for 1 h for the formation and aging of the pigment particles, after which the suspension was filtered and dried pasta. The final pH value of the suspension is 3.0. The filtrate is turbid and contains 2.8 g/DM3CrO3. The quality of the resulting phosphate are presented in the table.

Example 6 (control).

Synthesis is carried out analogously to examples 1 and 2, only a mixture of chromic and phosphoric acids add 0,065 cm 100%ethanol, which is 0.5 wt.% to the weight of the chromium phosphate. To the resulting mixture of chromic and phosphoric acids and ethanol under stirring slowly poured 18 cm3aqueous solution of hydrazine hydrate with a concentration of 11 wt.% N2H4. At the end of the feed solution of hydrazine - hydrate system is stirred for 1 h for the formation and aging of the pigment particles, after which the suspension was filtered and dried pasta. The final pH value of the suspension is equal to 8.0. The filtrate is transparent and contains 0.0002 g/DM3CrO3. The quality of the resulting phosphate are presented in the table.

Analyzing the examples described above, as well as data tables, we can conclude that the lack of hydrazine - hydrate leads to incomplete recovery of hexavalent chromium in trivalent and low pH of the suspension (example 5), and excess hydrazine hydrate does not improve quality indicators phosphate chromium, but leads to excess hydrazine hydrate (example 6). As for the reactant concentrations, they pick up so that the final concentration of the suspension of chromium phosphate was 50-100 g/DM3. At a lower concentration decreases yield and at a concentration of more than 100 g/is m 3with rapid increase in viscosity of chromium phosphate and deterioration of technological modes of its receipt.

The use of hydrazine - hydrate with a concentration of 10-12 wt.% due to the fact that at lower concentrations the formation and aging of particles of chromium phosphate stretches for several hours (at a concentration of 11 wt.% this 1-2 h), and at concentrations greater than 12 wt.% the reaction proceeds too rapidly.

Due to the fact that hydrazine hydrate at elevated temperatures (80-100°C)oxidized by oxygen in air (N2H4+O2=N2+2H2O) in the original mixture of chromic and phosphoric acid type (1-5) wt.% 100% ethanol (ethyl alcohol), which slows down the process of oxidation of hydrazine hydrate and reduce its losses. When the concentration of ethanol is less than 1 wt.% the effect of slowing down the process of oxidation of hydrazine hydrate is negligible, which leads to the need to increase its supply in the original mixture of chromic and phosphoric acids and ethanol. The process of drying the wet paste the increased concentration of ethanol has no effect, because the drying process at a temperature of (105-115)°With excess ethanol is evaporated and adsorbed phosphate chromium ethanol promotes disaggregation of particles of chromium phosphate, as evidenced by the indicator "residue on sieve 0056": 0.1 wt.% - in offer is emom the way and 0.3 wt.% - in the well-known (see table).

The method of obtaining anti-corrosion pigment - phosphate of chromium, including the recovery of hexavalent chromium to trivalent in the presence of orthophosphoric acid, filtering the suspension obtained chromium phosphate and drying, characterized in that the reactor has consistently served water, chromic anhydride, phosphoric acid and 1-5 wt.% ethanol to the weight of the final product, and the resulting mixture of chromic and phosphoric acids and ethanol slowly poured the strong reducing agent is an aqueous solution of hydrazine hydrate in an amount to provide education and aging of particles of chromium phosphate and the final pH of the suspension within 4-7 and phosphate concentration of chromium in the range of 50-100 g/DM3with subsequent filtering, returning the filtrate to the reactor in the preparation of the initial mixture of chromic and phosphoric acids and ethanol, as well as chromium reagent use chromic anhydride.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: anticorrosion pigment is produced from electric furnace wastes from foundry production - aspiration fines, containing, wt %: Fe2O3 63.9-70.0, FeO 7.0-11.32, SiO2 8.9-16, Al2O3 1.45-3.12. The aspiration fines are mixed in dry form with dolomite powder containing magnesium and calcium bicarbonate in amount of 80-95 wt %, with the ratio of aspiration fines to dolomite powder of 60-40:40-60 wt %, respectively. The obtained mixture is calcined for 3-5 hours at temperature of 700-800°C.

EFFECT: invention simplifies production of the anticorrosion pigment and lowers the calcining temperature.

1 tbl, 28 ex

FIELD: chemistry.

SUBSTANCE: agent contains water and fluorine-containing complex titanium and/or zirconium ions, an anticorrosion pigment, an organic polymer or copolymer which is water-soluble or water-dispersible, which as such in an aqueous solution in concentration of 50 wt % has pH ranging from 1 to 3. The agent also contains a polyvinyl amine with molecular weight greater than 100000 g/mol but not greater than 1000000 g/mol, the degree of acylation of the polyvinyl amines being not less than 80%.

EFFECT: invention improves bonding of a hardened ground coating with a metal surface and subsequent organic coatings.

14 cl, 2 tbl

FIELD: chemistry.

SUBSTANCE: anticorrosion protective polymer coating contains film-forming ethynol varnish, fine vermiculite filler and a plasticiser, which is divinyl styrene latex SKS-65, in amount of 0.05 pts.wt per 1 pts.wt film-forming agent.

EFFECT: high ductility and temperature stability of the coating, strength of adhesion thereof with boundary materials.

1 ex

FIELD: chemistry.

SUBSTANCE: anticorrosion and heat-insulating coating is made from an water-suspension composition with viscosity of 1-100 Pa·s, which includes a mixture of polymer binder 5-95 vol. % with filler - hollow microspheres 5-95 vol. %. The polymer binder is a water-emulsion polymer latex composition containing a (co)polymer selected from a group comprising an acrylate homopolymer, a styrene-acrylate, a butadiene-styrene and a vinyl acetate copolymer, polystyrene, butadiene polymer or a mixture thereof, a surfactant, water and ε-caprolactam. The filler used is a mixture of hollow polymer microspheres with diameter of 10-90 mcm and packed density of 25-40 kg/m3 and hollow glass microspheres, taken in ratio of 1:1.

EFFECT: invention increases resistance of the coating to thermal oxidative degradation, adhesion to hot surfaces as well as tensile strength and reduces specific weight.

3 ex, 3 tbl, 2 dwg

FIELD: chemistry.

SUBSTANCE: method involves preparing an aqueous solution substantially consisting of oxide nanoparticles and having pH 9-13, dissolving therein a prepolymer with viscosity of 3000-25000 mPa·s, depositing the solution on a substrate at temperature below 50°C and drying by heating. Overall duration of depositing and drying is less than 10 s. The prepolymer is obtained by polycondensation while mixing a first-category compound selected from a polyamine, a polyalcohol, a mixture thereof, with a second-category compound selected from a group comprising a polycarboxylic acid, a polycarboxylic anhydride, a polyepoxy, a polyisocyanate and any mixture of two thereof. The coating layer has thickness of 50-500 nm.

EFFECT: high protection of the metal from corrosion and high adhesion of paint when applied.

9 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: radiation curable, radically cross-linked composition consists of A) at least one radiation curable, radically cross-linked component, B) at least 2 wt % of at least one alkoxysilane component, with respect to the overall composition, which is selected from organofunctional silanes and/or epoxy-functional silanes, C) at least one acid-generating photoinitiator, D) one or more adhesion strength enhancing substances, E) one or more photoinitiators for radical curing and F) one or more pigments and ordinary target additives. The composition is used as a primer, an intermediate layer, lacquer coating, transparent lacquer and/or in coating or obtaining a coating by depositing on sheet metal. The invention also relates to a coating containing or based on the radiation curable composition.

EFFECT: after coating, compositions are capable of good moulding, thereby ensuring very high corrosion protection of metal substrates.

7 cl, 2 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: disclosed is an electrodeposited coating composition which contains (i) an electrodeposited film-forming polymer, (ii) a corrosion inhibitor and (iii) silane solution which does not contain an ethylenically unsaturated double bond, as well as versions thereof and substrates coated with said compositions.

EFFECT: reduced consumption of coating for obtaining a coating with improved anticorrosion properties and low environmental pollution.

26 cl, 2 tbl, 10 ex

FIELD: chemistry.

SUBSTANCE: invention relates to paint materials and can be used in mechanical engineering to protect metal surfaces operating at high temperatures, in highly corrosive conditions as well as at home and in industry. The heat-resistant enamel contains organoalkoxysilane-based methyl phenyl siloxane resin of general formula: [RhnSiO4n]a[Rm'SiO4m]b[Rk2SiO4k]c, where: n, m, k=1.2; R'=Me, H; a=0.1-33; R2=Me; b=0.03-1; c=0-0.1; as well as butyl methacrylate polymer, pentaphthalic lacquer, a heat-resistant pigment, micronised filler, a thickener, a bentonite clay-based rheologic additive and an organic solvent. The enamel enables to obtain a coating of high quality.

EFFECT: methyl phenyl siloxane resin used does not contain Cl-containing impurities, which improves environmental friendliness of the composition.

3 cl, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to paint industry and a paint coat having fire-proof and anticorrosion properties. Such a paint can be used in oil, gas and petrochemical industry, in public services and other sectors where there is need to protect surfaces of structures and components made from different materials, including when used in high temperature conditions. The paint contains organosilicon resin as binder, an organic solvent - xylene or paint thinner, filler - talc and kaolin with micro-wollastonite, a corrosion inhibitor in form of zinc phosphate with an additive of acid-free rust solvent based on tannins and target additives: emulsion of mineral oils based on paraffin and hydrophobic components, a solution of an alkaline liquid with silanol and a diurethane solution. The paint can further contain betolin and a drying agent.

EFFECT: invention increases fire resistance and improves anticorrosion properties of the coating.

3 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: method is realised by applying a heat shrink multilayer adhesive tape, having a protective layer made from polyethylene tape, electron-chemically modified and aligned in the common direction by 25-75%, and an adhesive layer made from a tape which is electron-chemically modified with accelerated ions with absorbed dose of 0.1 MGy, made from a composition which contains an ethylene and vinyl acetate copolymer with content of vinyl acetate groups of 10-14%, melt fluidity of 5.0-10.0 g/10 min and breaking strength of 9.8 MPa or an ethylene and vinyl acetate copolymer with content of vinyl acetate groups of 10-15%, melt fluidity of 2.0-6.0 g/10 min and breaking strength of 9.0 MPa, mineral filler, modifier - polyisocyante and sulphur-containing polyhydroquinone disulphide stabiliser in concentration of 0.1-0.3 wt %.

EFFECT: improved adhesion strength of the insulation material.

9 cl, 2 tbl

FIELD: chemistry.

SUBSTANCE: described is a method of making chromate anticorrosive pigment involving suspension of spent chrome-aluminium catalyst in aqueous solution of calcium nitrate and barium nitrate, taken in amount of 10-30% and 5-25% of the mass of catalyst respectively, in mass ratio of catalyst to the said nitrates equal to 65-70:30-35 respectively, dehydration of the obtained mixture with subsequent calcination at 800-900°C for 3-6 hours and grinding. The obtained pigment has anticorrosive effectiveness which surpasses that of the closest analogue by 6-40% and has lower cost.

EFFECT: use of pigment in ground coating improves anticorrosive properties of the coating and increases environmental friendliness.

1 cl, 1 tbl, 15 ex

FIELD: chemistry.

SUBSTANCE: method of producing emerald chrome pigment involves calcination of a mixture containing chromic anhydride, boric acid and urea, subsequent washing and drying the pigment. The mixture is calcined at temperature 750-800°C for 0.5-1.0 hours to obtain a melt which is boiled with addition of boric acid in mass ratio of melt to solution equal to 1:6. The mixture has the following weight ratio of ingredients: chromic anhydride - 20 pts. wt, boric acid - 60-80 pts. wt, urea - 3-4 pts. wt.

EFFECT: obtaining green pigment with a tinge of emerald green.

1 ex

FIELD: paint and varnish industry.

SUBSTANCE: anticorrosive pigment comprises , in mass per cents, 3.0-4.7 of calcium chromate and waterless dicalciumphosphate as the balance.

EFFECT: improved anticorrosion capabilities.

1 tbl

The invention relates to the technology for anti-corrosive pigments, for example, in the paint industry

The invention relates to methods for pigments containing chromium phosphate, used in the paint industry

The invention relates to the technology for anti-corrosive pigments used in the paint industry

The invention relates to the technology of production of pigments containing

The invention relates to the production of chromium oxide (III) used in the paint industry and for polishing

FIELD: construction.

SUBSTANCE: method to prepare charge to produce bioceramics includes dosing of initial components and their grinding in a planetary mill. Initial components are hydroxyapatite and sodium dihydrophosphate at the mass ratio of "hydroxyapatite/sodium dihydrophosphate" in the range of 20/80 - 85/15.

EFFECT: method makes it possible to prepare charge for bioceramics of new generation, capable of resorption and stimulating new bone tissue.

1 tbl, 1 ex

FIELD: varnish-and-paint industry.

SUBSTANCE: invention is designed for use in construction and chemical industry when dyeing building materials and parts, manufacturing enamels, glazes, ceramic paints, and polymer fillers. Pyroxene mineral (diopside or vollastonite) is brought into interaction in solution with salt colored by iron triad element cation (iron, cobalt, or nickel molybdophosphate) synthesized and crystallized directly in solution at 30-60°C. Interaction and precipitation of the salt on the surface of pyroxene mineral is effected during 15-30 min. Thus obtained precipitate is filtered and dried. Inorganic pigment 50-90% pyroxene mineral and 10-50% molybdophosphate. Color spectrum of pigments extends from lilac to brown depending on nature and quantity of chromophore.

EFFECT: increased coloration intensity and color purity.

2 cl, 2 tbl, 2 ex

The invention relates to a method of processing phosphate rock on obespechenie phosphates, used as fertilizer and feed product
Up!