Method of preparing anticorrosion pigment
SUBSTANCE: invention relates to protection of metals from corrosion using lacquer coatings. The engineering problem is solved using a method of preparing an anticorrosion pigment based on aspiration dust wastes from foundry electric furnaces. The aspiration dust is mixed with calcium hydroxide in water with content of calcium hydroxide in the mixture with aspiration dust equal to 8-11 wt %, and aspiration dust with calcium hydroxide in water is taken in ratio of 1:1 respectively. The obtained mixture is dried, calcined at 820-900°C for 3.5-5.5 hours and then ground up to the required degree of dispersion.
EFFECT: possibility of simplifying preparation of a highly efficient anticorrosion pigment and without presence of toxic components in it, as well as reduction of cost of the pigment and environmental conservation.
1 cl, 2 tbl, 15 ex
The invention relates to the field of protecting metals from corrosion paints.
It is known that the main protective function in the system of coatings on metals perform primers, anti-corrosive action of which is largely determined by the content and type of pigments. The most effective in this aspect are anti-corrosive pigments and inhibitors present in the coating composition can suppress corrosion processes even in violation of their integrity. However, the most widely used pigments-inhibitors, such as chromium and lead, are highly toxic.
A group of anti-corrosive pigments, representing an environmentally friendly alternative to chrome - and swingersadelaidel pigments, are ferrites are mixed oxides of the spinel structure of the General formula MeO·Fe2O3where Me is magnesium, zinc, tin, copper, calcium, cadmium, cobalt, barium, strontium, iron, manganese, see the book Korsunsky L. F., Kalin T.V., S. Stepin. Inorganic pigments. Ref. ed. - SPb.: Chemistry, 1992. S.138; article: Freedom M Properties of ferrites zinc and calcium as anti-corrosive pigments. // Protection of metals. - 1988. - 24. No. 1. - P.44-47; Nepesov K.K., Guriev, L.N., Vasiliev PS Physico-chemical and protective properties of ferrites metals (calcium, magnesium, zinc). // G go active. chemistry. - 1991. - V.64. No. 2. - S-425; Corrosion-electrochemical properties of systems steel-ferrites alkaline earth metals. / CAS, Longoria, Laslau. // Fo. Protection-92), 6-11 Sept. 1992. EXT. proc. Dokl. - S.; Protective properties of some ferritic metals. / CAS, Longoria, Laslau. // Theory and practice. electrochim. processes and Ecol. aspects of their use. Proc. Dokl. The age of three. nauch.-practical use. Conf., Barnaul, 1990. - S. These pigments are related to corrosion, protects the metal by means of giving an alkaline reaction corrosive environment, penetrating to the metal.
A method of obtaining anti-corrosive pigment - ferrite of calcium - iron oxide and calcium, see U.S. Pat. France 2396051, IPC C09D 5/08, 1979.
Recently, however, due to the depletion of the resource base is a significant rise in anti-corrosive pigments, therefore, more attention has been paid to obtaining pigments from waste products, see Kotelnikov BORN and other coating materials and their application. 1998, No. 6, p.8-10, and Savelyeva GT and other coating materials and their application. 1997, No. 7-8, p.14-16. On the one hand, many of technogenic wastes contain valuable components, and create places of burial of environmental problems. In many cases, these wastes are characterized by high dispersion. is it eliminates the need for preliminary grinding and activation of their surface when carrying out heterogeneous reactions of synthesis on their basis. Therefore, their use in obtaining anti-corrosive pigments is a promising way of reducing their value.
The closest in technical essence of the present invention is a method for anticorrosive pigment-based waste galvanoplastics containing oxides of iron and calcium. Before using galvanoscope washed from water-soluble salts, followed by drying, calcination and grinding to the desired degree of dispersion, see Makarov V.I., Ladygina O.V., Indacin E.A. Ferrites of calcium-based galvanostatic - new effective anti-corrosion pigments. // Paint-and-lacquer materials. - 1999. No. 5. - P.3-4.
The disadvantage of this method is the presence of a stage of washing galvanostatic from water-soluble salts with subsequent recycling of the wash water, in addition, the composition of galvanostatic includes compounds of chromium, resulting in increased toxicity of pigment.
The task of the invention is to simplify the process of obtaining high-performance anti-corrosive pigment without the presence in its composition of toxic components and industrial waste.
The technical problem is solved in that in the method of obtaining anti-corrosive pigment-based waste production, including drying and calcining, and RA is saying to the desired degree of dispersion, as waste use waste electric furnaces foundry - suction dust, including, wt.%: Fe2O3- 63.9-70.0, FeO - 7.0-11.32, SiO2- 8.9-16, Al2O3- 1.45-3.12, which is mixed with calcium hydroxide in water at a mass ratio of the specified suction dust and calcium hydroxide, equal 89-92:8-11, respectively, and the mass ratio of the above-mentioned mixture and water is 1:1, respectively, dried, and calcined at 820-900°C for 3.5-5.5 hours
Technical solution allows for exceptions washing of raw materials to facilitate the production of high efficient anti-corrosive pigment, surpassing the prototype to measure the effectiveness of the protective effect under optimal conditions obtain at 7.5% and does not contain toxic components.
Suction dust electric furnaces foundry - waste electric arc remelting steel is a fine powder reddish-brown color (specific surface in the initial state up to 3400 m2/kg), previously used in polyvinylchloride composition as a coloring component. Polyvinylchloride composition used in the manufacture of molded specialized products for Windows and doors for the construction and repair of buildings.
The composition of the dust suction (baghouse dust) the components go, wt.%: Fe2O3- 63.9-70.0; FeO - 7.0-11.32; SiO2- 8.9-16; Al2O3- 1,45÷3,12; MnO - 1,35÷3,82; CaO - 1,37÷3,13; MgO - 1,21÷of 5.83, see patent RU 2210579, C08L 27/06, 2003.
The resulting pigment is a highly dispersible powder dark brown color.
For a better understanding of the invention examples of specific performance.
Example 1 specific synthesis of pigment
Anti-corrosive pigment was prepared as follows. In 100 g of water is mixed with 92 g (92 wt.%) suction dust with 8 grams (8 wt.%) calcium hydroxide, then remove the water by drying. The resulting product is calcined at a temperature of 820°C for 5 hours, and then ground to the desired degree of dispersion.
Examples 2-15 similar to example 1. Conditions for obtaining pigment are shown in table 1.
For evidence of corrosion properties of the synthesized pigments were investigated the interaction of their aqueous extracts with steel. As a comparison object used ferrite pigment derived from galvanic sludge firm LLC Feros", Yaroslavl.
Test for anti-corrosive properties was carried out as follows.
As the samples used body steel 08 KP. Before the corrosion test was carried out by the abrasive surface with the subsequent degreasing mineral spirits and acetone.
About isocorrosion properties of the pigments was estimated by current density corrosion of steel in the background electrolyte and the electrolyte from the aqueous extract of the pigment and the indicator of the protective effect of γ.
As the background electrolyte used a 3%aqueous solution of sodium chloride. Aqueous extract of pigments prepared in accordance with the methodology described in the book, see Iagellonicae, Day, Iautomate. Laboratory pigments and pigmented paints, varnishes and lacquers. L.: Chemistry, 1990, s.
15 g of the pigment is placed in a chemical glass with a capacity of 150-300 ml, poured cylinder 50 ml of distilled water, heated to boiling and boiled for 30 minutes, the Suspension is cooled, the filtrate is poured into the cylinder and bring the volume to 50 ml with distilled water, then mixed with an equal volume of a 6%aqueous solution of sodium chloride. The resulting electrolyte is used for testing the next day after cooking.
The current density of steel corrosion is found from potentiodynamic polarization curves taken on the potentiostat at a rate of 0.2 mV/s in the area of potential corrosion (±30 mV) according to the method described in the articles, see Elisavetskiy A.M., Warriors, VN, Vlasov V.V., Katalov V.I. calculation of the parameters of equations of the kinetics of corrosion processes. Paints, No. 6, 1997, p.26-28; Abrosimova L.A., Kayumov A.A., Svetlakov A.P., sparrows Y.S. Determining current corrosion computer processing of polarization curves. // Paints and coatings. Current status and development trends. With whom. articles of the all-Russian scientific-of Techn. proc. students and young scientists, December 2005. The cauldron. state technology. University, Kazan, 2005, s-103.
The index of the protective effect of the pigment is determined by the formulawhere i0the current density corrosion in 3%sodium chloride solution (background electrolyte); i1the current density corrosion in 3%solution of sodium chloride containing aqueous extraction of the pigment, see the book beetle I.E. the Course of theory of corrosion and protection of metals. M.: metallurgy, 1976, p.350.
Anticorrosive properties of the pigments are shown in table 2.
As can be seen from examples of specific performance obtained by the present method, the pigments in corrosion properties are not inferior to the pigment obtained according to the prototype, containing toxic chromium components. Under optimal conditions obtain (example 6) protective effect in comparison with the prototype above 7.5%. In addition, in the process of obtaining a pigment-based suction dust no waste water.
Thus, the inventive method allows to obtain a high-performance anti-corrosive pigment-based waste foundry without the presence of the pigment composition of toxic components and industrial waste in its production and thereby reduce the cost and save the environment.
|Anticorrosive properties of pigments|
|Number example||Pigment||The current density corrosion, A/cm2||The index of the protective effect|
|A solution of sodium chloride||1.62·10-5||-|
|1||The claimed object||6.75·10-7||24.0|
The method of obtaining anti-corrosive pigment-based waste production, including drying and calcining and grinding to the desired degree of dispersion, characterized in that as a waste use waste electric furnaces foundry - suction dust, including, wt.%: Fe2O363,9-70,0, FeO 7,0-11,32, SiO28,9-16, Al2O31,45-3,12, which is mixed with calcium hydroxide in water at a mass ratio of the specified suction dust and calcium hydroxide, equal 89-92:8-11, respectively, and the mass ratio of the above-mentioned mixture and water is 1:1, respectively, followed by drying, calcination at 820-900°C for 3.5 to 5.5 hours
SUBSTANCE: according to the invention, the molecular imprinted polymer (MIP) is produced as follows. A reaction mixture containing a solvent, nylon 6 and a blowing agent is prepared. A template molecule is then added. The mixture is added to distilled water to obtain a separate molecular imprinted polymer. To obtain a polymer attached to the surface of a carrier, the mixture is distributed into a continuous thin layer or in form of spots. The obtained MIP is dried in air at room temperature. A template from the MIP composition is removed by successively washing with water and ethanol. The solvent used is a mono-alcohol. The blowing agent used is polyethyleneglycol, bovine serum albumin, polyvinyl pyrrolidone, polyvinyl pyrrolidone. Solvents whose rate of evaporation differs from the rate of evaporation of the mono-alcohol can also be used as the blowing agent. The solvents are selected from water, butanol, pyridine, dimethylsulfoxide, glycerin and dimethylformamide. The template used is mainly nucleotides and proteins.
EFFECT: method allows for cutting on time for producing a molecular imprinted polymer (MIP) and a MIP of high quality.
2 cl, 24 ex
SUBSTANCE: plastic composition with low viscosity, containing polyethylene with molecular mass of 1300-2700 - 100 pts.wt, and polyethylene with molecular mass of 1080-1250, or diesel fuel or engine oil instead of the latter - 10-20 pts. wt.
EFFECT: coating is water resistant, elastic, frost resistant, weather resistant and corrosion resistant.
SUBSTANCE: invention relates to protection and restoration of corroded metal surfaces working under abrasive wearing conditions, used in atmospheric conditions of different climatic zones, in the atmosphere of aggressive media, for example in power engineering, chemical and mining industry when repairing rusty equipment. The anticorrosion coating composition contains the following components in wt %: 21-35% modified alkyd filming agent, 1-2% rheological additive - surfactant based on TROYSOL fatty amine, 0.5-1% siccative, 4-12% filler, 5-10% zinc phosphate, 1-3% rust solvent based on tannins and tannin derivatives, specularite with high content of Fe2O3 and consisting of different fractions, 20-30% specularite of the first fraction with particle size not less than 63 mcm, 6-15% specularite of the second fraction with particle size not greater than 20 mcm, organic solvent - the rest.
EFFECT: proposed composition has good anticorrosion properties, abrasive wear resistance, high durability, is capable of dissolving rust without thorough preparation of the metal surface.
2 cl, 2 tbl, 7 ex
SUBSTANCE: invention relates to making coatings for different equipment and structural units of residential, public and industrial buildings and structures. Proposed is a paint-coating containing the following (in wt %): binder in form of solutions of acrylic (co)polymers and/or organosilicon resins in an organic solvent (10-25); additional binder in form of organosoluble polyurethanes (5-15); filler selected from microwollastonite, kaolin, micro-marble, micro-mica and/or inert barite filler (10-30); modifying additives made in form of ceramic and/or glass beads with size of 20-150 mcm (10-30); antipyrene additive (10-20) and pigment (2-4). The pigment used can be titanium dioxide. The suitable antipyrene additive is a compound from the group: phosphorus-containing compounds, hydroxides of aluminium or magnesium, zinc borate, melamine and pentaerythritol.
EFFECT: preparation of a coating with high thermo-, firer- and weather resistance, the coating also has good sound-proofing properties.
3 cl, 2 tbl, 9 ex
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: construction industry.
SUBSTANCE: invention refers to corrosion-resistant filler on the basis of lignified wastes of plant raw material, which is included in lacquer coatings and used for protection of metal surfaces against corrosion. Filler includes base made from lignified wastes of plant raw material crushed till powder is obtained, and amine-bearing addition. As lignified wastes of plant raw material, there used are fruit kernels (apricots, peaches, cherries, plums) and/or shells of nuts (walnuts, almond nuts, pistaches, coconuts, pine nuts, peanuts) or their composition with kernels of berries (grape, pomegranate, cornel), which are crushed to 5-40 mcm particle size. As amine-bearing addition, there used is monoethanolamine or triethanolamine.
EFFECT: filler has high corrosion-resisting properties and properties of rust solvent.
7 cl, 3 tbl
SUBSTANCE: anticorrosion coating composition which can be used for protecting steel structures, objects and equipment from corrosion in atmospheric conditions and aqueous media, contains finely dispersed zinc powder, polystyrene and/or a copolymer of styrene with rubber, organic solvent and a rheological additive, and additionally a binder in form of a polyisocyanate prepolymer - aromatic polyisocyanate prepolymer based on diphenylmethanediisocyanate and moisture-absorbing additives. The finely dispersed zinc powder is obtained through physical vapour deposition. The moisture-absorbing additive used is tosylisocyanate and/or micronised highly porous crystalline aluminium silicat. The rheological additive used is bentonite or montmorillonite. The organic solvent used is a solvent of oil or xylene or butylacetate or methoxypropylacetate or white spirit or mixture thereof.
EFFECT: improved physical and mechanical and protective properties of the coating based on the composition, reduced presence of defects in the coating, reduced consumption of the composition, with preservation of protective properties, increased stability during storage and longer storage life.
8 cl, 4 tbl
FIELD: production processes.
SUBSTANCE: blemished surface is covered with polyester resins Derakane 8084 as primer coat, after drying surface is covered with at least two layers of powder-bonded glass-fiber mat and three layers of surface film as reinforcing layer, these layers are resinated by Derakane 411-350, rolled, after drying protecting cover as wax top coat based on isophthalic polyester is applied.
EFFECT: improvement of coating service life.
3 cl, 1 dwg
SUBSTANCE: described is a heat resistant coating composition containing the following, wt %: polyorganosiloxane resin - 20-25, pentaphthalic lacquer - 8-14, isobutylmethacrylate polymer - 5-7, heat resistant pigment - 11-17, filler - 5-10, rheological additive - 1-2, thickener - 1-2 and organic solvent - the rest. The composition contains porous silicate in form of pearlite or kieselguhr, and the heat resistant pigment is aluminium powder or heat resistant pigments of different colours.
EFFECT: increased sedimentation resistance during storage and provision for coating with high resistance to physical and chemical effects.
3 cl, 2 tbl, 15 ex
SUBSTANCE: invention relates to anticorrosion zinc-containing coating compositions for corrosion protection of steel structures, objects and equipment used in average- and highly aggressive media and can be used in industrial and civil engineering, shipbuilding, motor car construction and bridge building for protecting engineering and hydraulic engineering structures, industrial and power installations, equipment of chemical and petrochemical industry, port structures. The anticorrosion composition contains finely dispersed zinc powder, zinc oxide, binder in form of chlorinated rubber, modified with alkyd resin with acidity of not more than 20 mgKOH/g and plasticised with chlorinated paraffin wax in a medium of organic solvent and target additives in form of polymerised amphoteric oil, organophilic bentonite and graphite.
EFFECT: obtaining one-pack anticorrosion composition with good processing characteristics with longer protection of coatings in average- and highly aggressive media.
SUBSTANCE: method for preparation of iron oxide pigment from specularite includes specularite milling up to particle size more than 1 mm - 5 mm, after material concentration with magnetic separation up to content of α-Fe2O3 more than 60.0 wt % specularite is concentrated again. Concentrated specularite can serve as starting material for obtaining of pigment with dull luster consisting of iron mica with Fe2O3 content more than 85 wt % which includes thin scaly plates in amount more than 50 wt % and is featured with residue after wet sieving on a sieve with mesh size 63 mcm not more than 35 wt %.
EFFECT: invention allows to obtain pigments from specularite for protective-decorative and decorative coatings.
8 cl, 2 tbl, 5 ex
SUBSTANCE: natural mechanically milled iron (III) oxide of lamellar structure at least 50 wt %, preferentially 75 wt %, contains particles sized 10 mcm and less in amount, at least, 50 wt %, preferentially 70 wt %, particularly preferentially 90 wt %. The ratio of thickness to maximum diametre of iron (III) oxide plates is 1:5, preferentially 1:10. To produce such iron (III) oxide, it is mechanically milled in an impactor or a jet-type mill. Iron (III) oxide resulted from mechanical milling, is separated by size grade, e.g. by an air separator. Iron (III) oxide can be used in lacquering for a base corrosion protection, mechanical load protection, UV and IR protection, for decorative coating, and also as an extender for polymeric and ceramic materials.
EFFECT: possibility to prepare highly dispersed lamellar particles of natural iron oxide.
SUBSTANCE: present invention pertains to production of black iron oxide pigments and can be used in paint and coating industry. The black iron oxide pigment is obtained from burning red mud - aluminous production waste. Before burning, the red mud is sorted according to size, with selection of the 0.02 mm fraction and further selection of the 0.02-0.045 mm fraction. These fractions are burnt in a controlled atmosphere with oxygen deficiency at 500-1000°C temperature.
EFFECT: obtaining iron oxide pigment of a pure black colour with 8-10 g/m2 coverage using aluminous production wastes - red mud, without more raw materials and additives and pollution of the environment.
FIELD: chemical industry; metallurgy industry; other industries; methods of production of the high purity ferric oxides.
SUBSTANCE: the invention is pertaining to the method of production of the high purity ferric oxides and may be used in production of the pigments and the catalysts at production of the high purity ferric oxides. The ferric oxides are produced by interaction of the metallic iron made in the form of the microball-shaped particles either the scrap, or the turning chips, which dimensions are such, that the area of their surface per one kg of iron and per one liter of the reaction medium makes more than 0.01 m2 with the being stirred water solution of the carboxylic acid having рКа from 0.5 up to 6 for the first carboxyl and capable to thermolysis in the open air at the temperature of from 200 up to 350°С into carbon dioxide and the water. The ratio between the moles of the carboxylic acid and g-atoms of the iron makes from 0.03 up to 1.5 and the mass ratio of the water/iron - from 1 up to 20, the microball-shaped particles are kept in the suspension by stirring. The produced carboxylate of the ferrum (II) is oxidized up to carboxylate of the ferrum (III) with the oxidant selected from oxygen, the oxygen-containing gaseous mixture and hydrogen dioxide. The earlier produced carboxylate of the ferrum (II) also may be exposed to the oxidizing. Then the carboxylate of the ferrum (III) is heated up in the open air till production of the oxides. The invention allows to increase the purity of the ferric oxides and productivity at their production.
EFFECT: the invention ensures the increased purity of the produced ferric oxides and productivity at their production.
9 cl, 12 ex
FIELD: chemical and paint-and-varnish industries; production of inorganic pigments.
SUBSTANCE: proposed method includes leaching-out of serpentine ore mixture containing magnesium and chromium by sulfuric or hydrochloric acid for obtaining iron-containing solution which is treated with hydrogen peroxide and is neutralized to pH= 7.0-8.0. Suspension thus obtained is filtered and iron hydroxide residue is dissolved with sulfuric or hydrochloric acid, then it is treated with alkaline reagent to pH=2.0-6.0 and is filtered. Then, iron hydroxide residue is washed off water-soluble ions, dried and burnt at temperature of 550-700C.
EFFECT: wide range of tints in processing and decontamination of sulfate and chloride waste obtained at production of periclase and chromite concentrate.
2 cl, 5 tbl, 6 ex
FIELD: pigment technologies.
SUBSTANCE: invention is intended for use in varnish-and-paint industry and in rubber and plastics production. Red iron oxide pigment preparation comprises: oxidation of aqueous solutions of ferric sulfate or suspensions of ferric hydroxide with air oxygen at quasi stationary temperature and pH values of reaction medium; hydrothermal heat treatment of suspension of ferric oxyhydroxides in periodical or continuous regimes in autoclaves; washing-out of pigment from water-soluble salts; drying and grinding of the pigment. During hydrothermal heat treatment FeOOH suspension is affected by nanosecond electromagnetic pulses having following characteristics: pulse duration 0.5-5 ns, pulse amplitude 4-10 kv, pulse repetition frequency 200-1000 Hz. Process is carried out at 130-200°С.
EFFECT: lowered FeOOH suspension hydrothermal heat treatment temperature and increased pigment preparation productivity.
1 tbl, 12 ex
FIELD: paint-and-varnish industry; construction engineering; painting plastics and leather; production of enamel paints, primers, putties, wall-paper and veneer.
SUBSTANCE: solution of hydraulic washing-out of used melt of titanium chlorates containing ferrous chloride (II) is treated with alkaline reagent to pH= 2.5-4.5 at precipitation of oxyhydrates of metals. Solution is separated from sediment by filtration. Cleaned solution thus obtained is mixed with solution obtained after leaching-out of copper-containing melt of process of cleaning titanium tetrachloride from vanadium compounds by means of copper powder. Ratio of volumes of said solutions is 1 : (0.5-2), respectively. Mixed solution is treated with alkaline reagent to pH= 9-11. Suspension thus obtained is subjected to filtering. Sediment is washed, dried and calcined additionally at temperature of 400-700°C. Proposed method makes it possible to utilize wastes of process of production of titanium dioxide from titanium tetrachloride. Pigment thus obtained has rich black color, reflection coefficient of 3.5±0.5%, hiding power of 4.5±0.5 g/m2 and pH of aqueous suspension of 7.0±0.5.
EFFECT: enhanced efficiency.
2 cl, 1 ex
FIELD: metallurgy; building industry; varnish and paint industry.
SUBSTANCE: the invention is pertaining to the field of metallurgy, building industry, varnish and paint industry, in particular, to the method of production of a red ferrioxide pigment. A ball mill is charged with industrial water, loaded with iron oxide with concentration of 500-900 g/dm3, poured with a neutralizing agent in the amount ensuring pH 6 ÷ 10. The iron oxide is formed at a thermal decomposition of the hydrochloride solutions used at etching treatment of carbon steels. As a neutralizing agent it is possible to use caustic soda, a slaked lime, microcalcite. The suspension is pulped for 3-5 hours, put in a reactor with a stirrer, where it is washed out with formation of a suspension, filtered off and dried. The target product has the following parameters: pH 5 ÷ 8; the share of water-soluble salts - 0.02-0.03 %; dispersing ability - 27-30 microns; hiding power - 6 ÷7 g/m2. The invention allows to simplify process and to upgrade parameters of the pigment.
EFFECT: the invention allows to simplify process and to upgrade parameters of the pigment.
2 cl, 1 tbl, 1 ex
FIELD: varnish-and-paint industry.
SUBSTANCE: invention is intended for use in chemical industry and construction for preparing varnishes, paints, and rubber products. Gas treatment slime from converter industry is fractioned, fraction up to 10 mm is dehydrated by drying at 70-110°C to at most 5% moisture content and reduced to particles not exceeding 300 μm in size. Color spectrum of product is extended from red to black by calcining disintegrated product at 300 to 900°C. Content of iron oxides in pigment is much higher than in pigments prepared using known processes.
EFFECT: widened resource of raw materials, utilized converter industry waste, and reduced price of product.
2 cl, 1 tbl, 6 ex
SUBSTANCE: invention can be used in pharmaceutical, medical, cosmetic, food and chemical industry, in production of plastic, rubber, pigments and paper. The method of producing a product which contains calcium carbonate in form of fine particles in one or more series precipitation reactors involves feeding calcium hydroxide in form of droplets and/or particles into a gas which contains carbon dioxide inside the precipitation reactor. Calcium hydroxide is fed through grinding and spraying devices working on the rod mill principle, placed inside the reactor or connected to the reactor. Temperature of the precipitation reactor is kept below 65°C due to installation in the reactor of cooling elements and/or material containing calcium carbonate and/or carbon dioxide-containing gas which circulates to the cooling device from the precipitation reactor and back to the precipitation reactor. Proposed also is a product which contains calcium carbonate and a device for making the said product.
EFFECT: invention enables to obtain fine calcium carbonate particles with size less than 100 nm and specific surface area greater than 20 m2/g, reduction of temperature and calcium precipitation time, increased degree of carbonisation of calcium hydroxide.
20 cl, 7 dwg, 1 tbl, 4 ex