Anticorrosive pigment

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 an anticorrosive pigments used in the paint industry.

Known anti-corrosive pigment, a complex salt of a phosphate-chromate calcium at a molar ratio of phosphate and chromate ions from 1:1 to 1:4, RU 2151157 C1.

The disadvantage of this pigment is very high toxicity due to the high content of chromium and good solubility of calcium chromate.

Known anti-corrosive pigment-based compounds of calcium, which represents a phosphate-chromate calcium at a molar ratio of phosphate and chromate ions from 4:1 to 20:1, RU 2199562 C1. This is a technical decision was made as a prototype of the present invention. This pigment is also quite toxic, however, it is obvious that its anti-corrosive properties below in comparison with the pigment according to EN 2151157 C1 due to the reduction in the share of chromate. Trehzameshchenny the calcium orthophosphate, which is a complex salt EN 2199562 C1 has a low solubility and low corrosion activity. A serious disadvantage of the prototype is its low thermal stability. It should be noted that for use in paint and varnish materials, hot curing pigment should have a temperature resistance of at least 300°C. Therefore, the pigment-prototype whose composition corresponds to the formula CaCrO4�B7; CA3(PO4)2·N2Oh, for use in such materials must be ignited at a temperature of 600-650°With removal of the crystal water and thereby increasing its heat resistance. It is necessary to specify that the annealing is a very expensive operation.

Thus, the disadvantages of the prototype are significant toxicity pigment, low corrosion activity and low temperature resistance.

The purpose of this invention is to improve the anticorrosive properties of the pigment, increasing its heat resistance, and reduced toxicity.

According to the invention in anticorrosive pigment-based calcium compounds as last used a mixture of calcium chromate and anhydrous dicalcium phosphate in the following ratio, wt.%: chromate calcium - 3,0-4,7; anhydrous dicalcium phosphate - rest.

Anhydrous dicalcium phosphate is about a thousand times better solubility than trehzameshchenny calcium phosphate. The result is fast enough, almost immediately after coating containing anticorrosive pigment, along with oxidation occurs phosphating a metal surface. This chromate calcium provides education on the metal surface of oxidelic, and dicalcium phosphate donates a phosphate anion, optionally forming a phosphate film.

In addition, the inventive pigment is a synergistic interaction of the components. In contrast with neutral reaction translesanas calcium phosphate, which is included in the complex salt pigment according to EN 2199562 C1, anhydrous dicalcium phosphate has an acidic reaction, which increases the intensity of the process of oxidation of the metal. Thus, one component, anhydrous dicalcium phosphate enhances the action of another component - chromate calcium, providing the oxidation of the metal surface.

The claimed pigment has a resistance of approximately 350°C, whereas thermal stability of the pigment of the prototype is not more than 180°With (under equal conditions, after drying, but without annealing). Temperature resistant pigments were estimated using thermogravimetry.

In the claimed pigment contained significantly less soluble chromates, which leads to decrease its toxicity.

The applicant did not know of any sources of information which are information about the distinctive features of the present invention and the technical result is being achieved as a result of their implementation (in conjunction with evidence contained in the restrictive part of the claims). These new properties object training is lowlevel, according to the applicant, according to the invention, the criterion of "inventive step".

To obtain an anticorrosive pigment in suspension of anhydrous dicalcium phosphate with a pH of 7.5 to 8.0 fall asleep chromic anhydride and stirred for 20 minutes. Then the suspension is filtered and dried at a temperature of 95-220°C. To use the obtained pigment it is introduced in the composition of the primers or enamels in the number of 7-9 wt.% by weight of the total primer or enamel.

Anticorrosive properties of the pigment is measured using a potentiostatic method.

As the corrosive medium was applied 3% solution of sodium chloride at pH 4.5, the prescribed solution of acetic acid. The calculation of the corrosion currents were conducted by the method: Gorlovka I.A., Indacin E.A., Tolmachev I.A. Laboratory pigments and pigmented paints, varnishes and lacquers. - L., "Chemistry", 1990

The claimed pigment does not require annealing, which is a very expensive process, and can be used in paint coatings hot curing immediately after drying.

Properties of the claimed pigment and the prototype shown in the table.

No. if measureThe content of the chromate calcium, wt.%Electrochemical potential (after the shock the LCD 48 h) (mV) the corrosion current (µa)Corrosion. braking (Ohms)
1.3,03509,4537
2.4,03509,7236
3.the 4.7360for 9.4738
4.1,534510,832
5.6.045015,030
6.The placeholder41013,231

The table shows that the corrosion properties of the claimed pigment significantly better in comparison with the prototype. When you reduce the content of calcium chromate below the lower limit (up to 1.5 wt.%) reduced electrochemical potential, increases the corrosion current and reduced corrosion inhibition, which significantly degrades the quality of the pigment.

With increasing content of chromate calcium above the upper limit (up to 6.0 wt.%) electrochemical potential increases, but increases significantly the corrosion current, which negatively affects the quality of the product.

For the manufacture of pigment used is known raw materials and simple factory equipment. This circumstance, according to the applicant, allows the so to the conclusion that this invention meets the criterion of "industrial applicability".

Anticorrosion pigment based on calcium compounds, characterized in that compounds of calcium used a mixture of calcium chromate and anhydrous dicalcium phosphate in the following ratio, wt.%:

Chromate calcium3,0-4,7
Anhydrous dicalcium phosphateRest



 

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FIELD: pulp and paper industry; methods of production of the pigment for manufacture of the cardboard and paper.

SUBSTANCE: the invention is pertaining to the method of production of the pigment for manufacture of the cardboard and paper and may be used in pulp and paper industry at production of the filled paper, the coated paper and the cardboard. Calcium carbonate is treated with aluminum sulfate in the aqueous medium. The treatment is conducted at aluminum sulfate consumption of 25-105 % to the mass of absolutely dry calcium carbonate at the temperature of 80-85°С during 90-180 minutes with production of the suspension containing 25-35 % dry substances in it. The suspension may be additionally dried and to produce the powder. The technical result of the invention is improvement of the pigment quality and expansion of the field of its application.

EFFECT: the invention ensures improvement of the pigment quality and expansion of the field of its application.

2 cl, 2 tbl

FIELD: pulp and paper industry; methods of production of the pigment for manufacture of the cardboard and paper.

SUBSTANCE: the invention is pertaining to the method of production of the pigment for manufacture of the cardboard and paper and may be used in pulp and paper industry at production of the filled paper, the coated paper and the cardboard. Calcium carbonate is treated with aluminum sulfate in the aqueous medium. The treatment is conducted at aluminum sulfate consumption of 25-105 % to the mass of absolutely dry calcium carbonate at the temperature of 80-85°С during 90-180 minutes with production of the suspension containing 25-35 % dry substances in it. At that they use the aqueous medium containing the binding chosen from the group, which includes starch and polyvinyl alcohol in the amount of 0.5-3.0 mass % from the mass of the absolutely dry pigment, and-or the water soluble colorant in the amount of 0.1-0.5 mass % from the mass of the absolutely dry pigment. The suspension is additionally dried and grinded. The technical result of the invention is the improved quality of the pigment as well as expansion of its field of application.

EFFECT: the invention ensures the improved quality of the pigment as well as expansion of its field of application.

2 tbl

FIELD: pulp and paper industry; methods of production of the pigment for manufacture of the cardboard and paper.

SUBSTANCE: the invention is pertaining to the method of production of the pigment for manufacture of the cardboard and paper and may be used in pulp and paper industry at production of the filled paper, the coated paper and the cardboard. Calcium hydroxide suspension is treated with aluminum sulfate solution in the aqueous medium at stirring. The treatment is conducted in the aqueous medium containing the binding in the dissolved state. The binding is chosen from the group, which includes starch and polyvinyl alcohol in the amount of 0.5-5.0 mass % from the mass of the absolutely dry pigment, and-or the colorant in the amount of 0.1-0.5 mass % from the mass of the absolutely dry pigment. The technical result of the invention is the improved quality of the pigment and expansion of its field of application.

EFFECT: the invention ensures the improved quality of the pigment and expansion of the field of its application.

2 tbl

FIELD: pulp and paper industry; methods of production of the pigment for manufacture of the cardboard and paper.

SUBSTANCE: the invention is pertaining to the method of production of the pigment for manufacture of the cardboard and paper and may be used in pulp and paper industry at production of the filled paper, the coated paper and the cardboard. In the water at intense stirring feed powders of calcium hydrate and calcium carbonate at the ratio of the indicated components accordingly from 1.0:2.2 up to 1.0:12.9. The produced suspension is gradually added with aluminum sulfate at its ratio to the total mass of the calcium hydroxide and calcium carbonate from 1.0:0.85 up to 1.0:4.30. Then the temperature of the mixture is increased up to 8О-85°С and the produced reaction mixture is kept at stirring within 90-180 minutes with formation of the dispersion of the pigment with the share of the dry substances in it equal to 20-35 %. Then the dispersion is dried and grinded into the powder. The powder is dispersed in the water containing the given amount of the dissolved coolant and-or binding - starch or polyvinyl alcohol. The technical result of the invention production of the pigment with the new properties, that allow to expand the field of its application at manufacture of various types of the cardboard and the paper.

EFFECT: the invention ensures production of the pigment with the new properties, expansion of the field of its application at manufacture of various types of the cardboard and the paper.

2 tbl

FIELD: paper-and-pulp industry.

SUBSTANCE: calcium carbonate product is designed for containing paper and comprises mixture of first and second separate calcium carbonate particles, wherein difference between first and second calcium carbonate particles ranges from about 0.1 μm to 0.2 μm and weight ratio of first to second particles lies between about 50:50 and about 80:20. Pigment is intended for coating paper and made from above-defined product. Method concerns containing paper and comprises preparation of mixed pigment based on calcium carbonate precipitated in the form of aragonite having above-indicated makeup; addition of binder; and deposition of the pigment onto a base paper in the form of binder-containing suspension. Paper is then dried and calendared. Also described are: paper obtained by above method; a method to increase gloss of paper sheet involving operation of including above product into base paper coating suspension; a method to increase gloss of paper involving operation including calcium carbonate product wherein first calcium carbonate particles have average size about 0.4 μm and the second ones about 0.5 μm at their weight ratio 60:40, respectively; a method to increase gloss of paper sheet involving operation of including pigment based on argonite-type calcium carbonate with difference between first and second average particle size values from about 0.1 μm to 0.2 μm and their weight ratio between about 50:50 and about 80:20 into base paper coating suspension.

EFFECT: increased gloss of coated paper sheets.

24 cl, 3 tbl

FIELD: paper-and-pulp industry.

SUBSTANCE: invention relates to pigment, which can be used in manufacture of paper with filler, coated paper, and cardboard. Calcium hydroxide and calcium carbonate powders taken in proportion between 1.0:2.2 and 1.0:23.5 are added to vigorously stirred water, after which temperature of mixture is raised to 80-85°C and resulting reaction mixture is kept being stirred for 90-180 min to form dispersion of pigment containing 20-35% solids.

EFFECT: improved quality of pigment at lower cost and extended application area.

3 tbl

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

-4
, H3PO4, oxalic acid or mixtures thereof in molar ratio to carbonate of 0.1-2. Used carbon dioxide under pressure of 0.05-5 bar may be added from outside, recycled or obtained by continuous H3O+-donors addition. Treatment with H3O+-donors and gaseous CO2 may be carriedout simultaneously or separately, wherein in the last case temperature and time of respective stages are 5-900C and 1-5 h. Claimed suspension is dried to obtain colorant. Colorant has BET specific surface of 5-200 m2/g according to ISO 9277 and mean grain size measured by sedimentation method of 0.1-50 mum. Colorants are used in compositions, as agent for paper lamination, for paper pulp filling, coloration, and board production. Obtained paper is useful in numeric and ink-jet printing.

EFFECT: paper with decreased mass at constant surface.

33 cl, 1 dwg, 2 tbl, 8 ex

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

The invention relates to the field of processing of inorganic materials to enhance their filling properties and can be used to obtain micronized chalk as filler in the chemical, rubber, paint, paper, electrical, cosmetic and other industries of moisture chalk

FIELD: production of pure phosphoric acid and calcium monohydrophosphate.

SUBSTANCE: proposed method includes decomposition of phosphate ore by first hydrochloric acid solution at concentration not exceeding 10 mass-%, separation of liquid decomposition product into insoluble solid phase containing admixtures and separate aqueous phase containing phosphate, chloride and calcium ions in form of solution, neutralization of aqueous phase separated from liquid decomposition product by adding calcium compound for obtaining insoluble settled-out calcium phosphate by means of phosphate ions, separation of neutralized aqueous phase into aqueous phase containing calcium and chloride ions in form of solution and settled solid phase on base of water-insoluble calcium phosphate and dissolving of at least part of separated settled solid phase in second aqueous hydrochloric acid solution containing hydrochloric acid in the amount exceeding its content in first hydrochloric acid solution, thus forming aqueous solution containing phosphate, chloride and calcium ions extracted by organic extracting agent at extraction in "liquid-liquid" system. Proposed method makes it possible to avoid fine grinding or roasting of ore.

EFFECT: enhanced efficiency of extraction for production of pure concentrated phosphoric acid solution with no contamination of surrounding medium.

24 cl, 2 dwg, 1 tbl, 4 ex

FIELD: inorganic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for preparing fodder calcium phosphates, namely to producing monocalcium phosphate. Method involves mixing wet-process phosphoric acid with a calcium-containing component in the presence of recycle, granulation and drying the product. Mixing process is carried out for two stages. At the first stage wet-process phosphoric acid with the concentration 62-65% of P2O5 is fed and process is carried out at recycle index = 1:(0.3-0.5) up to decomposition degree of calcium-containing raw = 0.89-0.92 at this stage. The second stage is combined with granulation and carried out its in high-speed mixer in water addition to obtain moisture in mixture 9.5-13%. The rate and time for mixing are regulated to provide the decomposition degree of calcium-containing raw = 0.93-0.99, and temperature at the next drying stage is maintained in the level 105-115°C. Method provides simplifying the process, reducing energy consumption and preparing product with the high content of P2O5 in water-soluble form and low content of fluorine.

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2 cl, 3 ex

FIELD: industrial inorganic synthesis.

SUBSTANCE: monocalcium phosphate, widely applied in agriculture, is prepared by mixing extraction phosphoric acid with calcium-containing component followed by granulation and drying of product. During mixing of components, appropriate temperature and moisture are maintained to ensure viscosity of mixture 3-7 mPa*s, and granulation and drying are carried out simultaneously in drum-type granulator drier. Calcium-containing component is either calcium carbonate or mixture thereof with limestone, whose does not exceed 15% of total weight of calcium-containing raw material. Moisture content in worked out drying agent leaving drum-type granulator drier equals 70-80 g per 1 kg dry air.

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3 cl, 3 ex

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