Method of obtaining magnetoactive compound

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Method of obtaining magnetoactive compound includes addition of nitrous acid salt to acidified solution of iron (II) salt, with further precipitation with alkali solution.

EFFECT: invention makes it possible to obtain magnetoactive iron compound with high relative magnetic susceptibility.

3 cl, 1 tbl, 57 ex

 

The invention relates to the production of magnetic compounds.

Particles of magnetic compounds can be formed due to the condensation of individual molecules. The size of the resulting particles is significantly influenced by the conditions under which there is a Union of individual molecules in the particles, therefore, to obtain colloidal particles of magnetic materials use different variants of the method.

One of the variants of the method of the condensation reaction is a chemical condensation of fine magnetite [Elmore W.. // Phys. Rew., 1938, V.54, P.309]:

2FeCl3+FeCl2+8NaOH→Fe3O4↓+8NaCl+4H2O.

10%solutions of FeCl2·4H2O and FeCl3·6H2O mixed at 70°C and with constant stirring to add an excess of 10%NaOH solution. To limit the growth of particles was used intensive mixing of the solutions. To obtain magnetite desired composition ratio of salts of Fe3+/Fe2+should be 2 to 1.

There are ways of obtaining magnetic fluids and contrast media based on organic compounds. As the magnetic component used magnetite precipitated from a mixture of salts of iron (II) and iron (III) 25%solution of ammonium hydroxide (U.S. Pat. The USSR№№568598, 861321, 966015, 978860).

Replacement of sodium hydroxide to ammonium hydroxide allows soosa the Denia salts at 25...40°C.

Closest to the proposed method is a method, in accordance with which it is originally from a solution of salt of iron (II) is precipitated carbonate of iron (II), which is at a temperature of 55...60°C for 1 h becomes magnetized magnetite separated from the liquid by decantation to pH 7 [U.S. Pat. Of the Russian Federation No. 2230705. IPC7C01G 49/08. The method of obtaining magnetic connection // Belikov VG, Coregen A.G., Sajeev SO, Zulfikarov I.N. Application: 2000109795/02, 19.04.2000. Published: 20.06.2004].

The disadvantage of this method is low relative magnetic susceptibility of the resulting magnetic connection.

The task of the invention to provide a magnetic connection with high relative magnetic susceptibility.

This is achieved by the fact that magnetic connection is formed by deposition of acidified solution of iron salts (II), which is conducted in the presence of nitrite.

The proposed method is as follows. To the acidified solution of salt of iron (II) is added to the estimated amount of the salt of nitrous acid and the resulting solution podslushivaet. Eye-catching turquoise precipitate quickly compacted and after some time turns into a magnetic connection with high relative magnetic susceptibility.

Example . For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.32 mg/ml, 5 ml nitric acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 26°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 20 min after mixing of the reagents, was 20.0 g/g of iron.

Example 2. The deposition of the magnetic compound was carried out under the conditions of example 1, wherein measuring the relative magnetic susceptibility spend 60 minutes after mixing the reagents. The relative magnetic susceptibility was 27.2 g/g of iron.

Example 3. The deposition of the magnetic compound was carried out under the conditions of example 1, characterized in that the reaction mixture was kept in an incubator for 5 min at 40°C. the relative magnetic susceptibility amounted to 16.3 g/g of iron.

Example 4. The deposition of the magnetic compound was carried out under the conditions of example 1, characterized in that the reaction mixture was kept in an incubator for 60 min at 40°C. the relative magnetic susceptibility was 27.8 g/g of iron.

Example 5. The deposition of the magnetic compound was carried out under the conditions of example 1, distinguished by the s, however, what the reaction mixture was kept in an incubator for 5 min at 50°C. the relative magnetic susceptibility was 19.5 g/g of iron.

Example 6. The deposition of the magnetic compound was carried out under the conditions of example 1, characterized in that the reaction mixture was kept in an incubator for 60 min at 50°C. the relative magnetic susceptibility was 28,0 g/g of iron.

Example 7. The deposition of the magnetic compound was carried out under the conditions of example 1, characterized in that the reaction mixture was kept in an incubator for 2 min at 100°C. the relative magnetic susceptibility was 3.6 g/g of iron.

Example 8. The deposition of the magnetic compound was carried out under the conditions of example 1, characterized in that the reaction mixture was kept in an incubator for 5 min at 100°C. the relative magnetic susceptibility was 9.7 g/g of iron.

Example 9. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.2 mg/ml, 5 ml acetic acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 26°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility measured in 20 mi is after mixing of the reagents, was 3.7 g/g of iron.

Example 10. The deposition of the magnetic compound was carried out under the conditions of example 9, characterized in that the measurement of the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 10.0 g/g of iron.

Example 11. The deposition of the magnetic compound was carried out under the conditions of example 9, characterized in that during the synthesis using formic acid. The relative magnetic susceptibility was 5.4 g/g of iron.

Example 12. The deposition of the magnetic compound was carried out under the conditions of example 11, characterized in that the measurement of the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 11.5 g/g of iron.

Example 13. The deposition of the magnetic compound was carried out under the conditions of example 9, characterized in that during the synthesis using hydrochloric acid. The relative magnetic susceptibility was 8.3 g/g of iron.

Example 14. The deposition of the magnetic compound was carried out under the conditions of example 13, characterized in that the measurement of the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 14.6 g/g of iron.

Example 15. Deposition magnetoactive the compound was carried out under the conditions of example 9, characterized in that during the synthesis uses sulfuric acid. The relative magnetic susceptibility was 5.4 g/g of iron.

Example 16. The deposition of the magnetic compound was carried out under the conditions of example 15, characterized in that the measurement of the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 12.8 g/g of iron.

Example 17. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.12 mg/ml, 5 ml nitric acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 26°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 20 min after mixing of the reagents, was 3.9 g/g of iron.

Example 18. The deposition of the magnetic compound was carried out under the conditions of example 17, characterized in that the measurement of the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 11.4 g/g of iron.

Example 19. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.2 mg/ml, 5 ml RA the creators of nitric acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. The synthesis was carried out at 26°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 20 min after mixing of the reagents, was 8.2 g/g of iron.

Example 20. The deposition of the magnetic compound was carried out under the conditions of example 19, wherein measuring the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 19.7 g/g of iron.

Example 21. The deposition of the magnetic compound was carried out under the conditions of example 1, wherein measuring the relative magnetic susceptibility conducted after 240 min after mixing of the reagents. The relative magnetic susceptibility was 30.5 g/g of iron.

Example 22. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.60 mg/ml, 5 ml nitric acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 40°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 5 min after mixing of the reagents, was 20.3 g/g of iron.

Example 23. The deposition of the magnetic compound was carried out under the conditions of example 22, wherein the change is giving the relative magnetic susceptibility spend 60 minutes after mixing the reagents. The relative magnetic susceptibility amounted to 22.2 g/g of iron.

Example 24. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.74 mg/ml, 5 ml nitric acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 50°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 5 min after mixing of the reagents, 20.1 g/g of iron.

Example 25. The deposition of the magnetic compound was carried out under the conditions of example 24, wherein measuring the relative magnetic susceptibility spend 60 minutes after mixing the reagents. The relative magnetic susceptibility was 21.3 g/g of iron.

Example 26. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml water, 5 ml of nitric acid concentration of 0.2% and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 40°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 20 min after mixing of the reagents was 1.5 g/g of iron.

Example 27. The deposition of the magnetic compound was carried out under the conditions of example 26, characterized those who, what is the measure of the relative magnetic susceptibility spend 30 minutes after mixing the reagents. The relative magnetic susceptibility was 1.9 g/g of iron.

Example 28. The deposition of the magnetic compound was carried out under the conditions of example 26, characterized in that the reaction mixture was kept in an incubator for 20 min at 50°C. the relative magnetic susceptibility was 5.2 g/g of iron.

Example 29. The deposition of the magnetic compound was carried out under the conditions of example 28, characterized in that the measurement of the relative magnetic susceptibility spend 60 minutes after mixing the reagents. The relative magnetic susceptibility was 9.1 g/g of iron.

Example 30. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.2 mg/ml, 5 ml water and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 26°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 20 min after mixing of the reagents, amounted to 7.2 g/g of iron.

Example 31. The deposition of the magnetic compound was carried out under the conditions of example 30, wherein measuring the relative magnetic susceptibility conducted after 300 min after mixing enjoyment of the assets. The relative magnetic susceptibility was 13.2 g/g of iron.

Example 32. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 10 ml water and 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 26°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured after 20 min after mixing of the reagents, amounted to 1.3 g/g of iron.

Example 33. The deposition of the magnetic compound was carried out under the conditions of example 32, characterized in that the measurement of the relative magnetic susceptibility spend 60 minutes after mixing the reagents. The relative magnetic susceptibility was 3.0 g/g of iron.

Example 34. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.32 mg/ml, 5 ml nitric acid concentration of 0.2%. The resulting solution was kept for 5 min and was added 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 22°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured 15 min after mixing of the reagents, 9.9 g/g of iron.

Example 35. The deposition of the magnetic compound was carried out under the conditions of example 34, the best of the relating to those what acidified solution was kept in the presence of sodium nitrite in 10 minutes relative magnetic susceptibility was 18.8 g/g of iron.

Example 36. The deposition of the magnetic compound was carried out under the conditions of example 34, wherein the acidified solution was kept in the presence of sodium nitrite within 15 minutes of the relative magnetic susceptibility of 20.3 g/g of iron.

Example 37. The deposition of the magnetic compound was carried out under the conditions of example 34, wherein the acidified solution was kept in the presence of sodium nitrite in 30 min. relative magnetic susceptibility of 20.3 g/g of iron.

Example 38. The deposition of the magnetic compound was carried out under the conditions of example 34, wherein the acidified solution was kept in the presence of sodium nitrite in 60 minutes relative magnetic susceptibility was 19.7 g/g of iron.

Example 39. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.32 mg/ml, 5 ml nitric acid concentration of 0.2% and immediately was added 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 22°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility,measured 15 min after mixing of the reagents, was 1.2 g/g of iron.

Example 40. The deposition of the magnetic compound was carried out under the conditions of example 39, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 11.8 g/g of iron.

Example 41. The deposition of the magnetic compound was carried out under the conditions of example 34, wherein measuring the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility amounted to 24.8 g/g of iron.

Example 42. The deposition of the magnetic compound was carried out under the conditions of example 35, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility amounted to 27.0 g/g of iron.

Example 43. The deposition of the magnetic compound was carried out under the conditions of example 36, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 26.3 g/g of iron.

Example 44. The deposition of the magnetic compound was carried out under the conditions of example 37, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min p is after adding NaOH solution. The relative magnetic susceptibility of 24.6 g/g of iron.

Example 45. The deposition of the magnetic compound was carried out under the conditions of example 38, wherein measuring the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 22.5 g/g of iron.

Example 46. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.32 mg/ml, 5 ml acetic acid concentration of 0.2%. The resulting solution was kept for 5 min and was added 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 22°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured 15 min after mixing of the reagents, was 1.0 g/g of iron.

Example 47. The deposition of the magnetic compound was carried out under the conditions of example 46, wherein the acidified solution was kept in the presence of sodium nitrite in 10 minutes relative magnetic susceptibility was 1.0 g/g of iron.

Example 48. The deposition of the magnetic compound was carried out under the conditions of example 46, wherein the acidified solution was kept in the presence of sodium nitrite within 15 minutes Relative the magnetic susceptibility was 4.9 g/g of iron.

Example 49. The deposition of the magnetic compound was carried out under the conditions of example 46, wherein the acidified solution was kept in the presence of sodium nitrite in 30 min. relative magnetic susceptibility was 12.9 g/g of iron.

Example 50. The deposition of the magnetic compound was carried out under the conditions of example 46, wherein the acidified solution was kept in the presence of sodium nitrite in 60 minutes relative magnetic susceptibility was 15.0 g/g of iron.

Example 51. For the deposition of magnetic compounds were mixed with 2 ml of a solution of sulphate of iron (II) concentration of 27.8 mg/ml, 5 ml of a solution of sodium nitrite concentration of 0.32 mg/ml, 5 ml acetic acid concentration of 0.2% and immediately was added 2 ml of NaOH solution concentration of 40 g/L. the Synthesis was carried out at 22°C. Immediately stood out sediment, turquoise. The relative magnetic susceptibility, measured 15 min after mixing of the reagents, 0.5 g/g of iron.

Example 52. The deposition of the magnetic compound was carried out under the conditions of example 51, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 7.2 g/g of iron.

Example 53. The deposition of the magnetic connection is rowdily in the conditions of example 46, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 9.0 g/g of iron.

Example 54. The deposition of the magnetic compound was carried out under the conditions of example 47, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 11.6 g/g of iron.

Example 55. The deposition of the magnetic compound was carried out under the conditions of example 48, wherein measuring the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 16.8 g/g of iron.

Example 56. The deposition of the magnetic compound was carried out under the conditions of example 49, characterized in that the measurement of the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility of 17.6 g/g of iron.

Example 57. The deposition of the magnetic compound was carried out under the conditions of example 50, wherein measuring the relative magnetic susceptibility conducted after 60 min after the addition of NaOH solution. The relative magnetic susceptibility was 17.9 g/g of iron.

The result is, obtained during the synthesis of magnetic compounds are summarized in table. In examples 1-33 condensation magnetic connection from the source acidified solution of iron sulfate (II) and sodium nitrite was performed within 1 hour after preparation of the initial solution. In order to evaluate the possibility of reducing the total time of the synthesis were carried out experiments which varied the duration of exposure of the original solution (experiments 34-57).

In the summary table in the 8th column shows the values of the length condensation (examples 1-33) in the examples that follow after the "/" shows the values of duration of exposure and duration of condensation.

As can be seen from the results 34-57 experiments, in order to obtain a magnetic connection with high magnetic activity, you need the original solution prior to condensation to withstand at least 5...15 minutes.

Thus, the proposed solution allows to obtain in a single phase magnetic connection, with a significantly higher relative magnetic susceptibility.

0/60
Conditions and results of synthesis MS
ExampleAcidThe concentration of the solution NaNO2 , g/mlThe volume of reagent solutions, mlThe synthesis conditionsOMV, g/gFe
FeSO4NaNO2acidt, °Cduration *, min
123456789
1HNO30,32255262020,0
2HNO30,32255266027,2
3HNO3 0,3225540516,3
4HNO30,32255406027,8
5HNO30,3225550519,5
6HNO30,32255506028,0
7HNO30,322551002 3,6
8HNO30,322551005the 9.7
9CH3COOH0,225526203,7
10CH3COOH0,22552624010,0
11HCOOH0,22552620of 5.4
12HCOOH0,225 52624011,5
13HCl0,225526208,3
14HCl0,22552624014,6
15H2SO40,22552620of 5.4
16H2SO40,22552624012,8
17HNO3 0,122552620a 3.9
18HNO30,122552624011,4
19HNO30,225526208,2
20HNO30,22552624019,7
21HNO30,322552624022HNO30,6025540520,3
23HNO30,60255406022,2
24HNO30,7425550520,1
25HNO30,74255506021,3
26HNO3-2- 540201,5
27HNO3-2-540301,9
28HNO3-2-550205,2
29HNO3-2-550609,1
30-0,225-26207,2
31-0,2 25-2630013,2
32--2--26201,3
33--2--26603,0
34HNO30,32255225/159,9
35HNO30,322552210/1518,8
36 HNO30,322552215/1520,3
37HNO30,322552230/1520,3
38HNO30,322552260/1519,7
39HNO30,32255220/151,2
40HNO30,322552211,8
41HNO30,32255225/6024,8
42HNO30,322552210/6027,0
43HNO30,322552215/6026,3
44HNO30,322552230/6024,6
45HNO30,32 2552260/6022,5
46CH3COOH0,32255225/151,0
47CH3COOH0,322552210/151,0
48CH3COOH0,322552215/15a 4.9
49CH3COOH0,322552230/1512,9
50CH3COOH0,322552260/1515,0
51CH3COOH0,32255220/150,5
52CH3COOH0,32255220/607,2
53CH3COOH0,32255225/609,0
54CH3COOH0,32255 2210/60the 11.6
55CH3COOH0,322552215/6016,8
56CH3COOH0,322552230/6017,6
57CH3COOH0,322552260/6017,9
* in the numerator duration of exposure, in the denominator - duration-condensing

1. The method of obtaining magnetic compounds by precipitation from a solution of salt of iron(II), characterized in that the deposition of the alkali solution is carried out after adding to the acidified solution of salt of iron(II) and nitrous acid.

2. The method according to claim 1, characterized in that the acidification of the solution of salt of iron(II) add the acid, mainly nitrogen.

3. The method according to claim 2, characterized in that before alkalization acidified salt solution of iron(II) incubated in the presence of sodium nitrite for 5-15 minutes



 

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2 cl, 1 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: 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 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 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: 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: 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

FIELD: medicine, pharmaceutics.

SUBSTANCE: invention can be used for creation of magnetic-susceptible sorbents applicable in medicine. A method for making magnetite nanoparticles stabilised by a biocompatible polymer having available functional formyl groups, involves preparation of magnetite of two mixed salts of ferrous iron and ferric iron adsorbed in polymeric matrixes, and modification of end groups of polymer. Magnetite is produced by coprecipitation in an alkaline medium of two mixed salts of ferrous iron and ferric iron, and at least one polymer selected from a number: chitosan, polyvinyl alcohol, block copolymer of polystyrene and polyethylene oxide. The weight relation of polymers in the composite makes 4 to 46 wt %. The produced composite is dispersed, processed in an aqueous solution of glutaraldehyde and washed. All the operations are combined with continuous ultrasound exposure.

EFFECT: invention allows producing multiuseable steady magnetite nanoparticles.

3 cl, 2 dwg, 1 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. The method of producing magnetite using red mud formed during production of aluminium via the Bayer process, involves at least a step for reducing magnetite and/or goethite to magnetite via reduction at least once. The reducing agent contains at least vegetable oil and/or fat and/or coal together with at least vegetable oil and/or fat.

EFFECT: invention enables to recycle red mud and improves environmental friendliness of the process of producing magnetite.

12 cl, 4 ex

FIELD: process engineering.

SUBSTANCE: invention relates to chemistry and metallurgy and may be used in producing valuable products from red sludge. Sludge processing comprises the following stages: a) reducing at least a portion of iron oxide (III) and/or iron hydroxide (III) contained in red sludge by at least one-type reducer that contains at least one-type hydrocarbon; b) separating at least one solid phase of reaction mix from at least one liquid and/or gas phase. Note here that said one solid phase, and/or liquid phase, and/or gas phase contains one valuable products containing at least magnetite. Methane and/or natural gas and/or ethanol may be used as said reducer. Separated solid phase is separated into one first magnetising produc and one second non-magnetising product. The latter is use as at least additive to cement. At least one component produced from gas phase separated at stage b) is used as initial product for synthesis of hydrocarbons. In said synthesis, at least one component of red sludge is used to make a surfactant.

EFFECT: expanded applications.

16 cl, 4 ex

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