Method of preparing magnetic liquid

FIELD: chemistry.

SUBSTANCE: method of preparing magnetic liquid involves dissolving starting iron-containing material in an inorganic acid, obtaining a solution which contains Fe2+ and Fe3+ salts, adding an alkaline solution to the obtained solution in order to deposit fine particles of magnetite, followed by stabilisation of the deposited fine particles of magnetite and peptisation of the stabilised magnetite particles in a dispersion medium. In the disclosed method, natural magnetite is first crushed in an inert medium to particle size 0.020-0.040 mm, and the fine particles of magnetite are stabilised with a mixture of synthetic fatty acids and oleic acid or naphthenic acids or a mixture of petroselinic and oleic acid. Also, the acids used to dissolve the starting iron-containing material can be sulphuric or orthophosphoric acid, and the fatty acids used are C7-C9, C10-C13 or C14-C16 fatty acids.

EFFECT: high stability of the magnetic liquid in gradient magnetic field, simple and cheap method.

3 cl, 5 ex

 

The invention relates to methods of producing colloidal solutions of nanosized magnetite particles in a hydrocarbon or other organic media, stabilized by different surfactants, such as magnetic fluids (MFS), which are widely used in various industries, for example in the oil industry: separating oil-water emulsions, when cleaning of oil tankers, when removing the oil film from the water surface; in the control and measuring devices for measuring the level in the oil tank, when determining flow when filling the tanks, when assessing the quality of welds trunk oil and gas pipelines.

A method of obtaining magnetic fluid (U.S. patent No. 3215572 from 02.11.1965, IPC H01F 1/44), in which large particles of magnetite grind in a ball mill in the presence of the dispersion medium, for example kerosene and stabilizer - oleic acid.

Common symptoms are known and the proposed method are: shredding of large particles of magnetite, the stabilization of the particles of magnetite and peptidase their dispersion in the environment.

The disadvantages of the known method of obtaining breast are the duration of grinding (from several days to several weeks), low productivity, a wide distribution of particles on the EPAM, that requires the removal of large particles with strong gradient magnetic fields to increase the stability of the sample.

Closest to the present invention is a method of obtaining MF (RF patent No. 2276420, publ. 10.05.2006, IPC H01F 1/28), in which the initial solution for the deposition of magnetite prepared by mixing sediment galvanic sludge (waste galvanic production) with concentrated hydrochloric acid to dissolve the base material (Fe2O3) followed by filtration of the solution and adding thereto spent pickling solution obtained by removing metallurgical mill scale (ferrous iron oxide) from the surface of metal ingots in a solution of inorganic acid. The ratio of Fe3+/Fe2+the resulting solution after mixing should be 3:2.

To thus obtained solution add ammonium hydroxide solution and the resulting suspension is affected by varying magnetic field with a frequency of 50 Hz, heat it up to 95°C, add kerosene and oleic acid with vigorous stirring and continue heating until the separation of the reaction mixture of organic and aqueous phase, which is removed with a pipette, and the remaining water is removed by heating the sample to 130°C. After cooling, the sample volume is brought up to standard by adding arocena and measuring the saturation magnetization of the obtained sample.

Common symptoms are known and the proposed method are: the dissolution of the original iron-bearing material in an inorganic acid, obtaining a solution containing salts of Fe2+and Fe3+,the deposition of fine particles of magnetite by adding to the resulting solution of the alkali solution, the subsequent stabilization of the obtained particles of magnetite and peptidase stable particles in the dispersion medium.

The disadvantages of this method are: the complexity of the equipment, the large time and energy costs of individual operations process.

a) Drying of the original sample-waste at 105°C.

b) filtering the solution after dissolution of the sample-waste in concentrated hydrochloric acid.

C) Long-term treatment of a suspension of magnetite magnetic field, and without specifying the parameters of the magnetic field and equipment for its creation.

g) Heating the suspension up to 95°C before the introduction of kerosene and stabilizer and the sample to 130°C to remove residual water.

d) the time spent on testing mixed solution of Fe2+and Fe3+and calculation of mixed volumes to obtain the solution after mixing a specified ratio of Fe3+/Fe2+=3:2.

In stoichiometric magnetite ratio of Fe3+/Fe2+=2:1. Therefore, either is the process of synthesis is the oxidation of ferrous iron, and then this process must be controlled, or if the ratio of Fe3+/Fe2+=3:2 will remain in the besieged particles of magnetite, the magnetic characteristics (saturation magnetization) of such particles will be less than that of stoichiometric magnetite.

e) High corrosivity of the source materials (galvanic sludge, waste pickle liquor), which requires the use of special equipment for storage.

To prepare the solution containing the salt of divalent or trivalent iron in the prototype, the use of hydrochloric acid solution galvanic sludge and spent pickling solution. The variability of their composition requires regular control over the content of Fe2+and Fe3+for maintaining a given ratio of Fe3+/Fe2+in the original solution. Source materials (galvanic sludge and etching solution) contain appreciable amounts of other elements. So, as a source of Fe3+in the prototype was used iron-containing waste "Severstal" (htceramix), contains (see the collection of scientific works of the 13th International Plyos conference on nano-magnetic fluids, ples, 2008, p.58), %:

Fe2O3- 48

FeO - 14

CaO - 9

SiO2- 6

MgO - 5

MnO - 5

Al2O3- 2, etc.

The composition of ferrous iron is not given. But this is residual, to assess the composition of the solution after dissolution of the precipitate in concentrated hydrochloric acid. Subsequent filtration of the solution significantly complicates the process of preparation of the starting solution for the deposition of magnetite. The addition of alkali leads to the formation of the suspension, which is treated with an alternating magnetic field. The need for prolonged treatment of a suspension of magnetite in the prototype suggests that the formation of magnetite is completed only after an hour and requires for its completion, additional equipment and energy costs.

Subsequent heating of the suspension to a temperature of 95°C., maintaining it after adding the dispersion medium (kerosene) and stabilizer (oleic acid) to bundle the resulting emulsion, and after removal of the aqueous phase heating breast up to 130°C to remove residual water require significant energy costs.

In the known method does not provide recycling the mother liquor, which included, in addition of ammonium salts and an excess of alkali, a whole range of metals, including heavy, high toxicity, and the need for full sewage treatment can be stumbling blocks in the organization of industrial production of the breast.

The technical challenge is to develop a simplified and economical method of obtaining MAGN is based fluid, sustainable in the gradient magnetic field.

This object is achieved in that in the method of obtaining magnetic fluid, which consists in dissolving the original iron-bearing material in an inorganic acid to obtain a solution containing salts of Fe2+and Fe3+, adding to the resulting solution of the alkali solution to precipitate fine particles of magnetite, leading to the stabilization of precipitated fine particles of magnetite and peptization stabilized magnetite particles in the dispersion medium, it is new that as the source of iron-containing material use natural magnetite, which is pre-milled in an inert atmosphere until the particle size 0,020-0,040 mm, and the stabilization of the precipitated fine particles of magnetite carried out with a mixture of synthetic fatty acids with oleic acid or naphthenic acid or a mixture petroselinic and oleic acids.

In addition, as the acid for the dissolution of the original iron-bearing material using sulfuric or ortho-phosphoric acid.

In addition, as a synthetic fatty acid use acid to the number of carbon atoms With7-C9or fatty acid ISO-structure with the number of carbon atoms With10-C13or C14-C16.

In the proposed sposobnostey material is natural magnetite, which has a high saturation magnetization and Curie point that is coincident with the magnetic characteristics of stoichiometric magnetite, which further emphasizes its purity. It is inert, and therefore can be stored even under the open sky.

Grinding particles of natural magnetite in an inert atmosphere to fit 0,020-0,040 mm allows to increase the rate of dissolution of magnetite, which leads to the possibility to use, in addition to hydrochloric, sulfuric or ortho-phosphoric acid. The use of sulfuric or phosphoric acids, on the one hand, reduces the corrosivity of the original solution, and on the other hand, facilitates the recycling of the mother liquor to obtain additional product: gypsum or phosphate and alkaline solution, which can be reused for the deposition of fine particles of magnetite. The ratio of Fe3+/Fe2+in the obtained solution by the proposed method is always 2:1, as in stoichiometric magnetite, and no analyses of the solution is not required.

After adding to the obtained solution of iron salts of ammonia solution in the proposed method, the obtained precipitate after a few minutes is a crystalline magnetite. Additional processing suspensions of magnetite magnetic field is not required. In predlagaemoe after deposition of crystalline magnetite large part of the mother liquor is removed by decantation, and then (at room temperature) to a suspension type stabilizer and the disperse medium. Stratification resulting suspension occurs already at low heat, when the temperature of the reaction mixture does not exceed 60°C. the decrease in the volume of the suspension after the precipitation of magnetite by removing the mother liquor and the low temperature of the suspension after the introduction of the stabilizer and the dispersion medium leads to a reduction in energy costs. After washing the Breasts with distilled water to remove salts stock solution residual water is removed in MG-separator for a few seconds.

The simplification process is also achieved due to the lack of stage filtration hydrochloric acid solution, exceptions analysis of mixed solutions on the content of Fe2+and Fe3+and calculate the volumes of the mixed solutions, eliminating time-consuming processing of suspensions of magnetite magnetic field.

The simplification process is also achieved due to the absence of pre-drying of the source material (galvanic sludge) at 105°C, exceptions heating the suspension of magnetite up to 95°C before the introduction of the stabilizer that reduces energy costs.

Reducing the cost of the equipment is achieved due to the absence of storage tanks for raw materials (in the prototype - galvanic sludge, travel the CSOs solution), and equipment for long-term treatment of a suspension of magnetite magnetic field.

The proposed method of producing the magnetic fluid does not require for its implementation of the imported equipment and reagents in the synthesis of the samples, with high requirements on the stability of the gradient magnetic fluid in a magnetic field.

Use MF in the processes FGS - or MG-separation eliminates transportation costs of shipping breast to consumption. Compared with the prototype source material - natural magnetite does not contain any impurities that may affect the composition and magnetic properties of sediment magnetite, and the mother liquor after separating the stabilized particles of magnetite contains only ammonium salt and a slight excess of alkali and, therefore, may be disposed in one of the known methods.

In the proposed method is able to significantly expand the range used stabilizers, some of which allow you to obtain the samples with higher saturation magnetization (for example, a mixture of synthetic fatty acids with oleic acid or naphthenic acid or a mixture petroselinic and oleic acids) at equal viscosity MF compared with the samples stabilized by oleic acid.

But the most important indicator of MF on the proposed SPO the training is to obtain samples sustainable in the gradient magnetic field. However, it is not possible to compare the proposed method and the prototype for this indicator due to the lack in the prototype of relevant data on the sustainability of MF in the gradient magnetic field.

The proposed method is as follows.

The sample of natural magnetite milled to a particle size of 0.02-0.04 mm in an inert atmosphere, which use nitrogen or carbon dioxide. Then, the magnetite is dissolved in an inorganic acid, which can be used sulfuric, or phosphoric, or hydrochloric acid. The dissolution process is carried out at a temperature not exceeding 45°C. After that, the resulting solution, after cooling it to room temperature quickly added with vigorous stirring NH4OH or NaOH, or KOH. The amount of alkali added to 1,2-1,5 excess compared with the stoichiometric need, as recommended in the organization of industrial production of the MF. After 3-5 minutes, stop stirring and allow to settle the formed particles of magnetite. After deposition of the particulate magnetite mother liquor is removed by decantation, and the suspension of magnetite add the stabilizer in the amount of 18-25% by weight of magnetite. As a stabilizer, a mixture of synthetic fatty acids7-the 9or fatty acids ISO-structure with the number of carbon atoms of the C10-C13or C14-C16with oleic acid or naphthenic acid, or a mixture petroselinic and oleic acids.

The stabilization process is carried out at room temperature, and then stabilized particles in suspension is mixed with a dispersion medium, which is usually used kerosene. The amount of the dispersion medium is selected depending on the requirements received breast.

After adding a dispersion medium to a stable suspension of particles of magnetite, the reaction mixture begins to delaminate. The process ends with weak stirring and heating the mixture to 50-60°C. the Upper (aqueous) layer was removed and the bottom (MF) is washed with distilled water. The washed liquid is passed through MG-separator, where the remaining water is removed in seconds. The saturation magnetization of the fluid can vary depending on the number entered dispersion medium within 30-60 kA/m, Then determine the stability of the obtained sample breast in a gradient magnetic field according to standard procedures.

Experimental validation of the proposed method were carried out in laboratory conditions. Below are examples of specific performance of the claimed technical removed the I.

Example 1. In a conical flask with a capacity of 1000 cm3download 65.0 g of magnetite, pre-milled in an atmosphere of CO2to a particle size of 0.02-0.04 mm, and poured 280 cm3sulfuric acid of 50% concentration. The dissolution is carried out at 45°C and stirring. After complete dissolution the solution is cooled to room temperature and thereto with vigorous stirring to 400 cm3an aqueous solution of ammonia of 25% concentration. After 3 minutes stop stirring and allow to settle the formed particles of magnetite. The mother liquor is removed by decantation, after which a suspension of magnetite gradually heated to 60°C. under weak stirring. The stabilizer is a mixture of synthetic fatty acids ISO-structure of C10-C13and naphthenic acids, taken in the ratio 1:1 - enter immediately after the start of mixing (25-30°C)and kerosene at a temperature of 35-40°C, and the dispersion medium (kerosene) is injected in small portions in the lower part of the reaction mixture. The amount of stabilizer is 16,0 cm3and kerosene - 100 ml After separation of the reaction mixture, the upper layer was removed and the breast is washed with distilled water, and then passed through a magnetic separator to remove residual water. Received 125 ml breast density 1.24 g/cm3and the saturation magnetization of the Is=421 kA/m

Example 2. To sample the natural magnetite weight of 65.0 g, pre-milled in a nitrogen atmosphere to a particle size of 0.02-0.04 mm, poured with stirring, 350 ml of 28% hydrochloric acid. The dissolution process is carried out at 40°C. To the resulting solution was quickly poured with vigorous stirring 30 ml of 40% NaOH solution, which is closing in 5 minutes, and allow to settle the formed particles of magnetite. Then the mother liquor is removed and the remaining slurry with weak stirring of 16.0 ml of the stabilizer, which is used as a mixture of synthetic fatty acids7-C9and oleic acid in the ratio of 0.3:1.0 in. Then the reaction mixture is gradually heated to 60°C.

At a temperature of 35-40°C, the suspension is added a dispersion medium (kerosene) in an amount of 100 ml with heating up the reaction mixture it splits into two phases. The aqueous phase is removed and the hydrocarbon (MF) is washed with distilled water and passed through MG-separator. The sample obtained in the amount of 120 ml, a density of 1.28 g/cm3. The saturation magnetization reaches 39.6 kA/m

Example 3. The raw materials and the conditions of the experiment are the same as in example 1, except that the magnetite is dissolved in phosphoric acid, adding 50% of the acid in the amount of 150 ml, and as a stabilizer a mixture of synthetic the IRNA acids ISO-structure With 14-C16with oleic acid in the ratio of 0.3:1.0 in. When this stable particles of magnetite were baptisimal in kerosene, which was introduced in the amount of 80 ml of the sample Obtained in the amount of 103 ml, a density of 1.32 g/cm3and the saturation magnetization 53,2 kA/m

Example 4. Conditions and starting materials are the same as in example 1 except that the deposition of fine particles of magnetite using KOH, and to stabilize them - a mixture of acids petroselinic, oleic acid and synthetic fatty acid (number of carbon atoms With7-C9) in the ratio of 1.6:1.0 to:0,3. The sample obtained in 128 ml, a density of 1.23 g/cm3and the saturation magnetization 38,9 kA/m

Example 5. Almost completely repeated the conditions of the experiment in example 1, except that in order to stabilize the precipitated magnetite particles, a mixture of acids petroselinic, oleic acid and synthetic fatty acids ISO-buildings (with number of carbon atoms With10-C13) in the ratio of 1.6:1.0 to:0,5. Received a sample of the same characteristics with the sample obtained in example 4.

All samples tested for stability in a gradient magnetic field and demonstrated its suitability for use in the processes of MG-separation.

Thus, the proposed method of obtaining breast is visible mainly the over prototype, since the proposed method is to be used in the consumption of MFS and there is no need to transport the products to other regions.

Source material - natural magnetite can be stored for a long time without changing magnetic and other characteristics.

Preparation of the starting solution, the proposed method does not require filtering and analysis of the obtained solution on the content of Fe2+and Fe3+. After deposition of magnetite particles do not require long-term treatment of a suspension of magnetite magnetic field and heating it to 95°C. the Energy cost of carrying out the stages of drying, filtering, initial solution, processing the magnetic field and heating of the suspension of magnetite used in the method prototype is sufficiently large. When the saturation magnetization of the obtained MF even after prolonged treatment of a suspension of magnetite magnetic field is small, and the content of large particles of magnetite, determine the stability of the samples the breast, was not determined.

In the proposed way the formation of magnetite ends in a matter of minutes, and the saturation magnetization MF can reach up to 80 kA/m and above.

Finally, if the mother solution, the proposed method can be disposed in one of the known methods, recycling the mother liquor is in the prototype will require a significant investment, which will affect the cost of the obtained liquid.

The proposed method also allows to expand the range of fatty acids used in the synthesis of magnetic fluids, which in some cases results in samples with a higher saturation magnetization than the samples stabilized by oleic acid, at equal viscosity samples.

1. A method of obtaining a magnetic fluid, which consists in dissolving the original iron-bearing material in an inorganic acid to obtain a solution containing salts of Fe2+and Fe3+, adding to the resulting solution of the alkali solution to precipitate fine particles of magnetite, leading to the stabilization of precipitated fine particles of magnetite and peptization stabilized magnetite particles in the dispersion medium, characterized in that the source material, use of natural magnetite, which is pre-milled in an inert atmosphere until the particle size 0,020-0,040 mm, and the stabilization of the precipitated fine particles of magnetite carried out with a mixture of synthetic fatty acids with oleic acid or naphthenic acid or a mixture petroselinic and oleic acids.

2. A method of obtaining a magnetic fluid according to claim 1, wherein as the inorganic acid to dissolve the texts of the source material uses sulfuric or phosphoric acid.

3. A method of obtaining a magnetic fluid according to claim 1, characterized in that as a synthetic fatty acid use acid to the number of carbon atoms of the C7-C9or fatty acids, isotrate with the number of carbon atoms With10-C13or C14-C16.



 

Same patents:

FIELD: electricity.

SUBSTANCE: invention relates to a powder magnetic core for operation at high frequencies produced by stamping of an iron-based magnetic powder coated with an insulation film, with specific resistance of less than 1000; preferably below 2000; and most preferably below 3000 mcOhm·m, magnetic induction of saturation B above 1.5, preferably higher than 1.7; and most preferably higher than 1.9 T. The invention also relates to manufacturing of such cores, and also to a powder suitable for such manufacturing.

EFFECT: reduced losses for vortex currents, maintenance of low level of losses for hysteresis, increased specific electric resistance of magnetic cores is a technical result of the invention.

11 cl, 2 tbl, 2 ex

FIELD: electricity.

SUBSTANCE: method involves preparation of charge on the basis of oxides of the above ferrite material and temporary binding agent representing water solution of polyvinyl alcohol and methyl cellulose at their specified ratio, pressing of workpieces from charge, sintering at the specified speed of temperature rise and reduction, cutting, grinding, finishing of items, metal coating of the specified surfaces of items. Prior to finishing of items, high-temperature annealing is performed at sintering temperature of ferrite material, at oxygen pressure above equilibrium pressure, which is equal to 0.1×105-1.0×105 kPa, during 30-60 min, and metal coating of the specified surfaces of items is performed with thickness of metallisated coating equal to 3-7 mcm.

EFFECT: improving reliability and yield ratio of items, reducing tangent of angle of total dielectric and magnetic losses, improving reliability and durability of integral microwave devices.

3 cl, 1 tbl, 5 ex

FIELD: metallurgy.

SUBSTANCE: invention can be implemented at production of anechoic chambers eliminating reflection of radio-waves from walls of chamber. Radio-absorbing ferrite contains, mol %: nickel oxide 10.0-16.0; copper oxide 2.0-6.0, zinc oxide 28.0-33.0, calcium titanate 0.5-5.0, ferric oxide - the rest.

EFFECT: high radio-absorbing properties.

1 tbl, 1 ex

FIELD: process engineering.

SUBSTANCE: invention relates to powder metallurgy, particularly, to materials intended for production of rare-earth permanent magnets. Powder is placed on magnet body surface and features composition R1aTbAcMd, where R1 is rare-earth element including Sc and Y, T - Fe and/or Co, A - boron and/or carbon, M -Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta or W. Powder comprises R2 oxide, R3 fluoride or R4 oxifluoride where R2, R3 and R4 are rare-earth elements including Sc and Y, and has mean particle size of not over 100 mcm. Thermal treatment of magnet body and powder is conducted at temperature equal to or smaller than magnet body sintering temperature to allow absorption of R2, R3 and R4 into magnet body. Absorption treatment is performed, at least, two times.

EFFECT: sintered magnet R-Fe-B with high operating properties.

14 cl, 1 tbl, 6 ex

FIELD: process engineering.

SUBSTANCE: invention relates to powder metallurgy, particularly, to materials intended for production of rare-earth permanent magnets. Powder mix is placed on magnet body surface and features composition R1 -Fe-B, where R1 is, at least, one of rare-earth elements including Sc and Y. Powder mix comprises powder containing, at least, 0.5 wt % of M with mean particle size not exceeding 300 mcm, and powder containing, at least 30 wt % of R2 fluoride with particle size not exceeding 100 mcm, where M is, at least, one element from the group including Al, Cu and Zn, R2 is, at least, one element of rare earth metals including Sc and Y. Magnet with powder mix is subjected to thermal treatment at temperature not exceeding that of magnet body sintering in vacuum or inert gas to allow absorption of, at least, M or R2 in magnet body.

EFFECT: R1-Fe-B sintered magnet features high operating properties at minimum amount of used Tb or Dy.

12 cl, 8 tbl, 8 ex

FIELD: process engineering.

SUBSTANCE: invention relates to powder metallurgy, particularly, to materials intended for production of magnetically hard ferrites. Invention may be used for purification of effluents, in magnetic filters, as well as crushing bodies in electromagnetic apparatuses. Composition comprises strontium hexaferrites, aerosil in gel state and thermally treated sludge formed in neutralising halogen organic compounds including calcium chloride and fluoride.

EFFECT: composition allows increasing magnetic and strength characteristics and simplifying production process.

4 cl, 1 tbl

FIELD: physics.

SUBSTANCE: magnetorheological compositions can be used to provide high transmitted shift voltages in different devices. The composition contains an oil base, magnetisable particles of powdered iron, a dispersing agent and a thixotropic agent based on hydrophobically modified layered silicates.

EFFECT: stability of the composition in a wide temperature range and possibility of appearance of reversible properties in this entire range and reduction of viscosity of the composition at low temperatures.

11 cl, 8 ex

FIELD: radio engineering.

SUBSTANCE: antenna core is made by formation of soft magnetic metal powder by using resin as binding agent. At that, soft magnetic metal powder is amorphous soft magnetic metal powder corresponding to common formula (1): (Fe1-x-yCoxNiy)100-a-b-cSiaBbMc (1), and resin used as binding agent represents thermoreactive resin. M represents at least one element chosen from the group consisting of Nb, Mo, Zr, W, Ta, Hf, Ti, V, Cr, Mn, Y, Pd, Ru, Ga, Ge, C, P, Al, Cu, Au, Ag, Sn and Sb. Each of x and y represents atomic ratio, and each of a, b and c represents percentage atomic ratio meeting the following relations: 0≤x≤1.0, 0≤y≤0.5, 0≤x+y≤1.0, 0≤a≤24, 1≤b≤30, 0≤c≤30 and 2≤a+b≤30. Soft magnetic amorphous metal powder forms crystallites of nanocrystals, the size of which does not exceed 100 n.m.

EFFECT: increasing elasticity modulus of antenna core, its stability at increased temperatures.

20 cl, 3 tbl, 7 ex

FIELD: metallurgy.

SUBSTANCE: there is prepared charge containing 3-7 wt % of silicon powder, powder of ferrophosphorus at amount facilitating contents of phosphorus in charge not more, than 0.5 wt % and powder of iron as base. Produced mixture is compressed, is subjected to at least one operation of annealing at temperature 1100-1300°C with successive cooling and is sintered in atmosphere of nitrogen gas by cyclic method by alternating annealing and cooling till there are obtained required magnetic properties.

EFFECT: produced material possesses high specific electric resistance and low losses for eddy currents at satisfactory coercion force and magnetisation.

5 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to colloidal chemistry and can be used to prepare magnetic liquid used in tilt sensors, accelerometers etc. The method involves precipitation of finely dispersed magnetite, treatment of the magnetite precipitate for 15 minutes with 50% aqueous solution of acetic acid at temperature 80±2°C and rate of stirring the suspension not less than 1500 rpm, stabilisation of the magnetite with a surfactant while heating and stirring, monitoring complete removal of iron salts and excess content of the surfactant, dissolving the stabilised magnetite in a reference liquid in a vacuum while heating and stirring at a rate of not less than 1500 rpm. The surfactant used is oleic acid heated to temperature of the water-acetic suspension of magnetite. After stabilisation and each washing cycle, the magnetite undergoes magnetic separation. The reference liquid used is jet fuel with an ethyl cellosolve additive.

EFFECT: invention provides low viscosity of magnetic liquid in the entire range of working temperatures and high saturation magnetisation, as well as stability of these properties over time.

1 ex

FIELD: physics.

SUBSTANCE: method of preparing magnetic liquid involves formation of a suspension of magnetite nanoparticles, coating the surface of magnetite nanoparticles with an adsorbed layer of oleinic acid as a stabilising substance. The suspension of magnetite nanoparticles is then heated with the adsorbed layer of stabilising substance. A fraction containing the stabilised magnetite particles is separated from the suspension in kerosene as carrier liquid. The source of bi- or trivalent iron for obtaining the suspension of magnetite nanoparticles used is natural magnetite - wastes from Olenogorsk mining and concentration complex having the following chemical composition: Fetotal=65.6%, FeO=26.7%, Fe2O3=63.4, MnOmax=0.11%, CaOmax=0.60%, MgOmax=0.8%, Al2O3max=0.40%, Smax= 0.15%, P2O5max=0.025%, SiO2max=7.75%, Na2Omax=0.063%, K2Omax=0.063%. Natural magnetite is preliminarily dissolved in hydrochloric acid and re-precipitated with 28% ammonium hydroxide.

EFFECT: obtaining cheaper magnetic liquid and wider area of using the said liquid.

2 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in varnish and paint and other industries. The method of obtaining magnetite involves formation of iron (II) hydroxide with its subsequent oxidation. Iron (II) hydroxide is partially oxidised with a 0.4-6.0 % CuSO4 solution, after which the obtained precipitate is washed using a magnetic field.

EFFECT: invention simplifies the process of producing magnetite, shortens duration of the process and reduces power consumption.

2 cl, 3 ex

FIELD: physics.

SUBSTANCE: invention relates to preparation of magnetic liquids which are colloidal solutions containing fine particles of ferro- and ferrimagnetic materials stabilised by fatty acids for use when separating nonmagnetic materials according to density in control and measuring devices, in medicine etc. The method of preparing magnetic liquid involves partial oxidation of an iron (II) solution, precipitation of fine magnetite particles using an alkaline solution, separation of the mother solution and stabilisation of the magnetite particles. The iron (II) solution is partially oxidised using hydrogen peroxide taken in amount of 0.5 mol H2O2/mol of iron (II). Before or after partial oxidation of the iron (II) solution, sulphuric acid is added in amount of up to 0.33 mol/mol FeSO4. After stabilisation of magnetite particles and their peptisation in a dispersion medium to obtain an emulsion, magnetic liquid is removed. CaO is added to the mother solution while stirring. After removal of the formed CaSO4 precipitate, the mother solution is mixed with a new portion of partially oxidised iron (II) solution to obtain an additional amount of magnetic liquid.

EFFECT: method provides wasteless and cheaper technology of preparing magnetic liquid due to additional material and without reducing stability of the obtained magnetic liquid.

4 cl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to design of colloidal systems and can be used in different engineering fields. The method of producing water based magnetic liquid involves precipitation of magnetite from salts of di- and trivalent iron FeCI2·4H2O and FeCI3·6H2O using excess concentrated solution of ammonia, addition of sodium oleate to the aqueous magnetite suspension, heating the suspension and boiling while stirring constantly, cooling and centrifuging the mixture. Sodium oleate is used as a stabiliser and surfactant, the adsorption layer of which covers the surface of magnetite particles. Alternating magnetic field at frequency of 50 Hz acts on the aqueous magnetite suspension.

EFFECT: invention improves magnetic characteristics of magnetic liquid and allows for not using dodecylamine stabiliser which is expensive and difficult to obtain.

1 tbl, 5 ex

FIELD: physics.

SUBSTANCE: invention refers to production of liquid magnetised environments on various bases containing magnetite or ferrite particles and can be used for sealing devices, flaw inspection, control devices, and density separation of nonmagnetic material. Method of magnetic liquid production includes magnetite particles deposition by mixing bivalent iron aqueous solution with hydrogen peroxide alkaline solution, stabilisation and peptisation of processed magnetite particles in dispersion medium. Magnetite particles are deposited in the process of sputtering of bivalent iron solution in hydrogen peroxide alkaline solution, hydrogen peroxide alkaline solution being produced using 5-10% ammonia solution with hydrogen peroxide content of 0.3-0.4 H2O2 moles / FeSO4 moles. Magnetite particles stabilisation and peptisation in dispersion medium is carried out at room temperature, with magnetite particles stabilisation followed by dispersion of stabilised particles in hydrocarbon solvent. After that reaction mixture residual of mother solution decantation is heated up.

EFFECT: production of liquid stable in gradient magnetic field and applicable for density separation of nonmagnetic material.

2 cl, 2 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

The invention relates to the production of magnetic compounds used in medicine

The invention relates to the field of colloid chemistry and can be used for ferromagnetic materials: magnetic fluids (MF) used in the magnetic liquid seals, sensors, angle, acceleration, as the magnetic lubricants

The invention relates to the production of pigments from bog iron ore, used in the paint industry, for coloring building materials as fillers in the manufacture of plastics, rubber, linoleum and other products, in the world of typography as art paints

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

Up!