Method of producing anticorrosive pigment
SUBSTANCE: anticorrosive pigment is obtained from a mixture of pigment components of oxygen-containing metal compounds. The method of producing pigment involves heat treatment of the mixture and grinding the heat treated product. The anticorrosive pigment is produced from a suspension of its components. The anticorrosive pigment additionally contains a pigment inhibitor-component which is a waste from neutralisation baths of machinery production, with the ratio of components galvanic sludge: inhibitor-component equal to 1:1 (on iron and calcium oxides) based on calcium contained in the galvanic sludge.
EFFECT: obtaining cheap highly resistant anticorrosive pigments with a ferrite structure, obtained from galvanic sludge, and wide field of their use.
2 ex, 1 tbl, 1 dwg
The invention relates to the production of anticorrosive pigments that can be used for the preparation of conservation of lubricants. You know getting releaxing inorganic pigments industrial waste during the process of calcination of iron precipitation electrochemical treatment of wastewater of electroplating [A.S. USSR N1370124, CL SS 1/24, 1988]. The disadvantage of this method of obtaining pigments is the oxidation of compounds of trivalent chromium to chromium, which significantly narrows down the possible applications of such pigments. In addition, electrocoagulation cleaning galvanostatic implemented only on a small number of industrial production (8-12% of the total number of electroplating plants), whereas in most plants use chemical treatment of electroplating wastes precipitation with calcium hydroxide.
Closest to the proposed method of obtaining anti-corrosion pigment is a method of obtaining a pigment of the components of the pigment oxygen-containing metal compounds, including heat treatment of the mixture and grinding the heat-treated product. [RF patent N2055086, CL SS 1/28, SW 33/14, 1996]. The disadvantage of this method is the low corrosion resistance of the obtained pigments, representing a mixture of metal oxides.
The task of izaberete the Oia is getting cheap, durable, anti-corrosive pigments ferritic structure, derived from galvanostatic (GSH), and expanding the scope of their application.
This task is solved by the creation of an anticorrosive pigment having high anti-corrosion properties To increase the corrosion resistance properties of the pigments is added pigment component-inhibitor (CI), which is a departure after baths neutralization of machine-building productions, containing mainly calcium hydroxide CA(Oh)2. This waste has a fine structure and unlike other inhibiting substances particles of calcium hydroxide are in the form of flakes, so the pigments based on it have along with inhibiting and barrier effect.
The task is also solved by a method of obtaining anti-corrosive pigment of the components of the oxygen-containing metal compounds, including heat treatment of the mixture and grinding the heat-treated product, in which the mixture components are oxygen-containing suspension components suspension of sludge electrochemical treatment of wastewater of electroplating and suspension of the pigment component inhibitor (KI) - departure after baths neutralization of machine-building productions, containing mainly calcium hydroxide CA(Oh)2in the ratio is AI NG:KEY 1:1 (oxides of iron and calcium) with regard to calcium, contained in GSH. Economically justified, because the production initially after wastewater treatment formed suspension sludge having a moisture content up to 70%to keep it in further processing, the company has advanced it to dry to a moisture content of less than 5%, which leads to increased energy consumption and, as a consequence, the cost of raw materials. The proposed method allows to process sludge with high water content, namely up to 70%.
Suspension GSH and suspension KI thoroughly mixed in an amount such that the observed 1:1 ratio for ions of iron and calcium. The resulting suspension is filtered, and the residue is dried in a drying Cabinet. The mixture is mechanically fray and placed in ceramic crucibles. Then the crucible with the charge is placed in a preheated muffle furnace, where calcined at 900°C for one hour. After the annealing crucible is transferred into a desiccator for cooling. The grinding of the obtained pigment is carried out mechanically.
The invention consists in the creation of technology for durable, anti-corrosive pigments brown palette of colors based on the recycling of electroplating waste and baths neutralization engineering companies, which currently are not implemented and are discharged into a dump, polluting the environment.p> The invention permits the processing of raw materials (galvanoscope) obtaining highly resistant anticorrosive pigments with good quality - hiding power, stability, heat resistance, providing a broad range of applications.
Additionally, to determine antikorrozionnym properties of the obtained pigments were determined currents corrosion potentiometric method. This was filmed polarization curves in anodic and cathodic areas. Similar curves were constructed for the industrial design of the pigment (THE No. 82.3.011-99). Polarization curves are used to determine corrosion rate, as they give valuable information about the nature of the corrosion process and allow us to calculate the absolute speed. Since the rate of the electrode process is controlled by the speed of the electrochemical reaction, i.e. the rate of discharge of hydrogen ions or ionization of metal, in semi-logarithmic coordinates, the dependence of the potential on the logarithm of the current density is expressed by a straight line. Extrapolating the straight stretches of these polarization curves, we can determine the values of the corrosion currents (so-called graphical method).
The obtained curves are presented in figure.
Example 1. The electrochemical galvanic sludge wastewater treatment galvanize the who manufacture washed with 90 ml of water, heated to a temperature of 50°C, then filtered, and the residue is dried in a drying Cabinet. The obtained dried sludge mechanically fray and placed in a ceramic crucible. Then the crucible with the charge is placed in a preheated muffle furnace, where calcined at 900°C for one hour. After annealing the crucible is transferred into a desiccator for cooling. The grinding of the obtained pigment is carried out mechanically to a particle size not exceeding 10 microns.
Example 2. In the suspension of galvanostatic electrochemical treatment of wastewater of electroplating (GSH) in addition impose a suspension of the pigment component inhibitor (KI) - departure after baths neutralization of machine-building productions, containing mainly calcium hydroxide CA(Oh)2in the ratio of GSH:KEY 1:1 (oxides of iron and calcium) subject to the calcium contained in GSH, carefully mix the resulting suspension is filtered, and the residue is dried in a drying Cabinet. The mixture is mechanically fray and placed in ceramic crucibles. Then the crucible with the charge is placed in a preheated muffle furnace, where calcined at 900°C for one hour. After the annealing crucible is transferred into a desiccator to cool.
The values of the currents corrosion:
for anticorrosive pigment in the slurry GSH:KI I=15,1 µa;
for GSH I=50 µa.
Thus, the corrosion rate for anticorrosion pigment based on the suspension of the General staff, where the additionally introduced pigment component-inhibitor (KI)is several times lower than for anticorrosion pigment based on the dry GSH. When using an anticorrosive pigment according to example 2, the potential is shifted in the positive direction by about 20 mV. This is due to the dual mechanism of action of ferrites on the basis of galvanic sludge and waste after baths neutralization of machine building production, which is associated with the formation of the optimal number of hydroxyl ions, sufficient for the passivation of the metal electrode.
Thus, the claimed technical solution allows you to develop a way to obtain cheap antikorrozionnym pigments derived from suspension galvanostatic (GSH) and suspension of the pigment component inhibitor (CI), to expand the scope of their application compared with the known solutions.
|Properties of the resulting anti-corrosive pigments|
|Indicators||The pigment of GSH (example 1)||The pigment suspension GSH:KI (1:1) (example 2)||P is gment in accordance with specifications No. 82.3.011-99||Test methods|
|The content of water-soluble compounds, not more than %||0,41||0,4||2||paragraph 4.7 on THE No. 82.3.011-99|
|The content of substances insoluble in hydrochloric acid, %||18||30||30-40||item 4.9 on THE No. 82.3.011-99|
|The cash portion of the iron compounds in terms of Fe2O3, %||67||57||35-70||item 4.4 on THE No. 82.3.011-99|
|The oil absorption, g/100 g pigment, no more than||22,9%||29,5%||40||GOST 21119.8-75 and paragraph 4.12 on THE No. 82.3.011-99|
|pH||8,5||10||7-11||GOST 21119.4-75 and paragraph 4.10 for THE No. 82.3.011-99|
|The residue after wet sieving sieve 0,063%, no more than||0,97||0,38||1||GOST 21119.4-75 and paragraph 4.11 on THE No. 82.3.011-99|
|Hiding power g/m2not more than||28||19||30||GOST 8784-75 and paragraph 4.13 on THE No. 82.3.011-99|
|Color||brown||brown||Within tolerances approved color sample||GOST 16873-78-75 and section 4.3 for THE No. 82.3.011-99|
|Current corrosion, MCA||50||15,1||not rules.||GOST 9.602-89 and 9.602-2005|
The method of obtaining anti-corrosive pigment of a mixture comprising the pigment oxygen-containing metal compounds, including heat treatment of this mixture and grinding the heat-treated product, wherein it is produced from a suspension of these components and further comprises a pigment component-inhibitor, represents a departure after baths neutralization of machine building production in the following ratio of the components of the galvanic sludge:component-inhibitor - 1:1 (oxides of iron and calcium) subject to the calcium contained in galvanos the AME.
SUBSTANCE: production wastes are dried and ground to the required fineness. The production wastes used are in form of sludge from clarification tanks of thermal power stations formed during liming and coagulation of raw water on a water treatment plant. The sludge is dried at temperature 200-250°C for 3-3.5 hours.
EFFECT: method enables to obtain a cheap inorganic chromatic pigment, reduces the cost of paint materials by simplifying the process of producing the pigment and using readily available and cheap production wastes, which enables to solve the problem of recycling sludge from clarification tanks of thermal power plants.
2 tbl, 6 ex
SUBSTANCE: invention relates to production of high-strength inorganic pigments which can be used to produce paint materials. The method of producing an iron-calcium pigment involves neutralisation of iron-containing spent solutions, containing sulphuric acid, with a calcium-containing reagent with deposition of a precipitate, filtration and drying the precipitate. The iron-containing spent solution used is waste water from abandoned deposits of iron-copper-zinc sulphide ores containing iron (III) sulphate and sulphuric acid. The waste water is neutralised until achieving reaction mixture pH of 4-5.
EFFECT: simple process and recycling of under-waste dump and quarry water from spent complex deposits.
2 cl, 2 ex
SUBSTANCE: invention can be used in chemical industry. The method of production of natural red iron oxide pigment from ore includes its reduction, cleaning using the method of magnetic separation and repeated reduction. The ore used can be hematite, martite, hydrohematite. First the ore is reduced to size no less than 10 mm, then it is reduced using wet method to particle size of 60-80% class smaller than 40 μm and is classified in 4 stages. Elutriation includes main elutriation, first rewashing, first control and second control hydrocycling. Then the oxidative destruction of sulfides contained in the ore is performed, as well as thickening and drying with simultaneous disintegration and dry elutriation of pigment.
EFFECT: increased pigment output, production environmental friendliness, decreased sulfur content in pigment and decreased waste amount.
1 dwg, 1 ex
SUBSTANCE: invention can be used to produce magnesium chloride, silica and red pigment. Serpentinite calcined at 680-750°C is treated with 4-8% hydrochloric acid solution with weight ratio of serpentinite to hydrochloric acid equal to 1:(15-40). The hot pulp is then decanted and filtered. The residue is dried to obtain silica, the filtrate is evaporated and silicic acid is separated. After separating silicic acid in form of sol-gel, hydrochloric acid is added to a solution containing magnesium and iron (III) chlorides until 4-8% hydrochloric acid solution is obtained. The obtained hydrochloric acid solution is used to treat a new portion of serpentinite. Further, the decantation, filtration, evaporation of filtrate, separation of silicic acid and treatment of the obtained solution with hydrochloric acid are repeated 3-5 times using new portions of calcined serpentinite. The solution concentrated that way at 90°C is mixed with serpentinite and filtered. Magnesium chloride is separated from the residue which contains iron (III) hydroxide. Said residue is treated at 350-400°C to obtain red pigment.
EFFECT: invention simplifies the processing serpentinite, improves environmental safety and reduces expenses and wastes.
1 dwg, 1 ex
SUBSTANCE: to prepare iron oxide pigments, wastes formed during hydraulic borehole mining for iron ore in form of mud containing martite, iron mica, goethite, magnetite and chamosite are mixed with a superplasticiser in ratio of 1:0.05 and wet grinding is carried out. Thermal treatment is then carried out for 1-1.5 hours at 100-150°C and next grinding is carried out in a disintegrator to obtain a 0.8-1.0 mcm fraction of the composition. The obtained iron oxide pigment has a brick-red colour, density of 4.42 g/cm3 and low oil consumption.
EFFECT: invention enables recycling of mining wastes and reduces power consumption.
SUBSTANCE: to obtain an iron-containing pigment, aqueous solutions of sodium or ammonium carbonate and magnesium chloride or sulphate are first mixed in equimolar ratio. A magnesium carbonate pulp is obtained and settled. After that the clear portion is decanted and washed 2-3 times with water in volume ratio pulp : water=1:(2-3), each time decanting the clear portion. Iron (III) sulphate solution is then added to the magnesium carbonate pulp. The obtained residue of iron hydroxides or hydroxocarbonates is filtered off, washed with water, dried and annealed.
EFFECT: invention increases output when preparing a pigment owing to 2-3 times faster filtration of the iron-containing residue.
2 tbl, 2 ex
SUBSTANCE: invention can be used in making paint, construction and ceramic materials, glass, enamel, plastic and rubber. The iron oxide based pigment contains two fractions of iron (III) oxide. The first fraction has a plastic structure with particle size not smaller than 20 mcm. The second fraction consists of particles of different shapes with size not bigger than 20 mcm. The said components of the pigment are in the following ratio in wt %: iron (III) oxide of the first fraction with plastic structure 3-97, iron (III) oxide of the second fraction with particles of different shapes 97-3.
EFFECT: invention enables to obtain a grey coloured pigment with metallic lustre to red, increases corrosion resistance and wear resistance of the paint coatings, reduces opaqueness and oil absorption.
9 cl, 3 tbl, 3 ex
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
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: invention relates to mineral filler with high specific surface area, which are used in several fields including the paper industry, and specifically as filler or coating dye. The method of producing a dye which contains surface-treated precipitated calcium carbonate involves steps for (a) providing at least one dye containing surface-treated precipitated calcium carbonate (PCC); (b) providing H3O+ ions; (c) providing at least one anion which is capable of forming water-insoluble calcium salts, said anion being dissolved in an aqueous medium; (d) bringing said dye which contains PCC into contact with said H3O+ ions and with said anions dissolved in an aqueous medium to form a dye suspension containing surface-treated PCC, said surface-treated PCC containing an insoluble, at least partially, crystalline calcium salt of said anion formed on the surface of the PCC, where excess dissolved calcium ions are provided at step (d). The invention also relates to a dye suspension containing surface-treated PCC, obtained using said method, use thereof and surface-treated PCC contained in the suspension.
EFFECT: invention provides high specific surface area of surface-treated precipitated calcium carbonate.
40 cl, 10 tbl, 10 ex
SUBSTANCE: method of preparing a processed product from mineral filler, which contains calcium carbonate, involves step a) for treating at least one dry mineral filler with a salt of group II or group III elements of C8-C24 aliphatic monocarboxylic acid to obtain an intermediate product from mineral filler; b) treating the intermediate product from mineral filler at step (a) with at least one C8-C24 aliphatic monocarboxylic acid to obtain a product from a processed mineral filler. The products obtained from the processed mineral filler are used for mixing and/or extrusion and/or compounding and/or blow moulding with plastic materials and, preferably, with polyolefins or thermoplastic materials such as polyethylene, polypropylene, polyurethanes and polyvinyl chloride.
EFFECT: invention reduces content of volatile substances in mineral filler.
2 dwg, 1 tbl, 11 ex
SUBSTANCE: invention can be used in inorganic chemistry. The method for dry grinding one or more mineral materials containing at least calcium carbonate involves steps for crushing the mineral material in a crushing unit to obtain crushed material with diameter d95 less than 10 cm, dry grinding the crushed material in a grinding unit in the presence of at one hydrophilic comb polymer containing at least one polyalkylene oxide group, grafted onto at least one ethylenically unsaturated monomer. Dry grinding is carried out such that the amount of liquid in said grinding unit is less than 15% of the weight of said crushed material in the grinding unit. The obtained material has mean diameter d50 from 0.5 to 500 mcm.
EFFECT: invention enables to grind mineral material without using a large amount of volatile organic compounds, without changing properties of the end product.
59 cl, 7 tbl, 5 ex
SUBSTANCE: invention can be used in making paper products. The gypsum product essentially consists of undamaged crystals, having weight-average diameter D50 0.1 - 2.0 mcm and particle size distribution width less than 2.0. The shape factor of the crystals is equal to at least 2.0 and the aspect ratio is equal to 1.0-10. The gypsum product is obtained by reacting calcium sulphate hemihydrate and/or calcium sulphate anhydrite and water in the presence of a crystal habit modifier. The reaction mixture has dry substance content of 50-84 wt %. The crystal habit modifier is used in amount of 0.01-5.0% of the weight of the calcium sulphate hemihydrate and/or calcium sulpohate anhydrite and is selected from a group consisting of ethylenediamine succinic acid, iminodisuccinic acid, ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid, nitrilotriacetic acid, N-bis-(2-(1,2-dicarboxyethoxy)ethylasparticacid, di-, tetra- and hexaaminostilbene sulphonic acid and salts thereof, such as sodium aminotriethoxy succinate (Na6-TCA), as well as alkylbenzene sulphonates. The crystallised or extracted gypsum is dispersed, treated with biocides, sieved and bleached.
EFFECT: high lustre and opacity due to that the gypsum particles are flat and have equal size.
18 cl, 11 dwg, 5 ex
SUBSTANCE: mixture is prepared from calcium sulphate semihydrate and/or calcium sulphate anhydrite and water with dry substance content of said mixture ranging from 34 to 84 wt %. The mixture is stirred until formation of a crystalline gypsum product. The reaction mixture can further be mixed with a calcium sulphate dihydrate or a crystal habit modifier selected from ethylene diamine amber acid, amino diamber acid, ethylene diamine tetraacetic acid, diethylene triamine pentaacetic acid, nitrilotriacetic acid, N-bis-(2-(1,2-dicarboxyethoxy)ethylaspartic acid, di-tetra- and hexaaminostilbene sulphonic acid and salts thereof, such as sodium aminotriethoxy succinate (Na6-TCA), as well as akylbenzene sulphonates. Water is used at temperature 0-100°C. Crystallised gypsum is dispersed using a dispersant in amount of 0.01-5.0 wt %, treated with a biocide, sieved and bleached. The obtained gypsum product essentially consists of intact gypsum crystals with size 0.1-2.0 mcm, shape factor 2.0-5.0 and aspect ratio 1.0-10.
EFFECT: simple method.
23 cl, 33 dwg, 28 ex
SUBSTANCE: invention relates to chlorionated thermoplastic materials with mineral filler, having compatibility between said filler and chlorinated thermoplastic resin. The mineral filler compatibility agent in form of calcium when producing chlorinated thermoplastic material contains a comb-shaped polymer which contains at least one polyalkylene oxide group which is grafted onto at least one ethylenically unsaturated anionic monomer. The comb-shaped polymer contains at least one anionic monomer with ethylenic unsaturation and a monocarboxyl or phosphoric group or mixtures thereof, at least one non-ionic monomer containing at least one monomer of formula (I): , where m and p denote the number of alkylene oxide groups, which is less than or equal to 150, n denotes the number of ethylene oxide groups, which is less than or equal to 150, q denotes a whole number equal to or less than 1, where 5≤(m+n+p)q≤150, R1 denotes hydrogen or a methyl or ethyl radical, R2 denotes hydrogen or a methyl or ethyl radical, R denotes a radical which contains an unsaturated polymerisable group, preferably associated with a group of vinyl compounds, or a group of acrylic, methacrylic, maleic esters, or a group of allyl or vinyl ethers, which are substituted or unsubstituted, R' denotes hydrogen or a hydrocarbon radical with 1-40 carbon atoms or a ionic or ionisable group, such as carboxyl, and preferably denotes a hydrocarbon radical with 1-12 carbon atoms. The invention also relates to chlorinated thermoplastic materials containing at least one chlorinated thermoplastic resin, calcium carbonate and at least one compatibility agent.
EFFECT: high impact strength.
22 cl, 4 tbl
FIELD: textiles, paper.
SUBSTANCE: composition comprises: a) a filler, b) a cationic inorganic compound - polyaluminumchloride, c) a cationic organic compound, and d) anionic polysaccharide. The filler is present in an amount of at least about 1% by weight, based on the total weight of the composition. Anionic polysaccharide is present in an amount from about 1 to about 100 kg/ton based on the weight of the filler. The composition is substantially free of fibers. Filler composition of the version contains the components a), b), c) and d), as defined above. The only difference is that the component c) is a cationic polyamine condensation polymer, and the component d) has a degree of substitution of stoichiometrically excess anionic groups of up to about 0.65. At that each of b) and c) components present in an amount from about 0 to about 30 kg/ton based on the weight of the filler. At that the composition comprises at least one of b) and c) components. Methods of obtaining compositions of filler comprise mixing a), b), c) and d), as defined above. The invention also relates to a filler composition, which is obtained by this method, an application of the filler composition as an additive to an aqueous suspension of cellulose in the production process of paper and to manufacturing paper comprising adding a filler composition to an aqueous suspension of cellulose. The invention also relates to a paper obtained with this method, and paper comprising the filler composition.
EFFECT: improvement of composition.
35 cl, 1 dwg
SUBSTANCE: invention can be used in chemical industry. The method of producing jointly ground calcium carbonate material, which contains ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC) with coefficient of curvature at least equal to approximately 30, preferably at least approximately 40 and even more preferably at least approximately 45, comprises the following steps: a) obtaining at least one calcium carbonate material, optionally, in form of an aqueous suspension; b) combined grinding of GCC and PCC, optionally, with at least another mineral material which is selected from talc, clay, Al2O3, TiO2 or mixtures thereof; c) optional sieving and/or concentration of the jointly ground calcium carbonate obtained after step (b); d) optional drying of the jointly ground calcium carbonate material obtained after step (b) or (c). The coefficient of curvature is defined as d30/d70×100, where d30 and d70 denote equivalent spherical diameters, relative which 30 wt % and 70 wt % particles have a smaller size.
EFFECT: invention enables to improve optical properties of enamel paper and exclude the PCC deagglomeration step.
40 cl, 2 tbl, 4 ex
SUBSTANCE: invention can be used in chemical industry. The method of producing jointly ground calcium carbonate material, which contains ground calcium carbonate (GCC) material and precipitated calcium carbonate (PCC) comprises the following steps: a) obtaining at least one calcium carbonate material, optionally, in form of an aqueous suspension; b) combined grinding of GCC and PCC, optionally, with at least another mineral material which is selected from talc, clay, Al2O3, TiO2 or mixtures thereof; c) optional sieving and/or concentration of the jointly ground calcium carbonate obtained at step (b); d) optional drying of the jointly ground calcium carbonate material obtained at step (b) or (c). The fraction of particles of the obtained material with size smaller than 1 mcm is greater than 80%, preferably greater than 85%, more preferably greater than 90% and even more preferably greater than 95%. BET specific surface area is less than 25 m2/g.
EFFECT: invention enables to increase lustre of enamel paper.
44 cl, 2 tbl, 5 ex
SUBSTANCE: present inventions relate to a method of producing precipitated calcium carbonate (PCC) and the design of a low-power reactor system for realising the method such that, the amount of dry residues in the PCC product can be increased to 35% or more without a dehydration step. The disclosed method involves steps for bringing calcium hydroxide into contact with a carbon dioxide-containing gas in parallel or two or more separate reaction vessels in order to form calcium carbonate. Calcium oxide, lime or dry calcium hydroxide or a combination of any of the three components are also added to a portion of the obtained mixture of calcium hydroxide and calcium carbonate. When used in the production of PCC, the reactor system has at least one reactor vessel with an optional water inlet and gas inlet and at least one recirculation reservoir for inlet of components and optional water inlet.
EFFECT: use of the disclosed method and device ensure efficient and economical production of PCC with a given structure and high content of dry residues.
21 cl, 8 dwg, 9 ex
FIELD: chemical and pulp-and-paper industry.
SUBSTANCE: aqueous suspension of at least one filler or mineral contains natural carbonate, polymeric dispersing agent as stabilizer of suspension viscosity, product of natural carbonate treatment with gaseous CO2, and product of natural carbonate reaction with at least one medium or strong H3O+-donors, has pH more than 7.5 at 200C. As natural carbonate suspension contains calcium carbonate (e.g., marble, calcite, carbonate-containing dolomite, chalk, ore mixtures thereof with talcum, and/or TiO2, MgO, or other minerals inert to H3O+-donors). As H3O+-donors suspension contains H2SO3, HSO
EFFECT: paper with decreased mass at constant surface.
33 cl, 1 dwg, 2 tbl, 8 ex