CS271544B1 - Magnetic liquid and method of its production - Google Patents

Abstract

The solution applies to a magnetic liquid containing 0.1 to 20 weight parts of ferromagnetic metal, 0.1 to 20 weight parts of fatty acid with 10 to 20 carbon atoms (stabiliser), 0.1 to 20 weight parts of anionic tensides (dispersing agent) and to complete 100 weight parts,a liquid carrier. The magnetic liquid can be prepared by the precipitation of a solution of ferromagnetic metals by an organic or anorganic base or by the reduction of gas at a temperature of 0 to 15 degrees C. To the separated precipitate a fatty acid is added, the mixture is heated to 90 to 110 degrees C and at this temperature it is being mixed and water is being removed for 4 to 10 minutes until a paste is made. To the paste dispersing agent a liquid carrier is added. The solution can be used in ore separation, in the sealing of rotatory machine gearboxes and in hydraulic device production etc.

Description

(57) The present invention relates to a magnetic liquid comprising 0.1 to 20 parts by weight, ferromagnetic metal, 0.1 to 20 parts by weight, a fatty acid having 10 to 20 carbon atoms (stabilizer), 0.1 to 20 d. %, anionic surfactants (dispersant), and up to 100% by weight, liquid carrier. The magnetic liquid can be prepared by precipitation of a solution of ferromagnetic metal salts with an organic, inorganic base or reducing gas at a temperature of 0 to 15 ° C. The fatty acid is added to the separated precipitate, the mixture is heated to 90-110 ° C and kept at this temperature with stirring and de-watering for 4-10 minutes to form a paste. The resulting paste is added with a dispersant and a liquid carrier. The solution can be used for ore eeparation, sealing of gearboxes of rotating machines, production of hydraulic equipment, etc.

The invention relates to magnetic liquid and to a process for its production. The magnetic fluid is a stable colloidal suspension of the particles of ferromagnetic metal is stabilized and dispersed auxiliaries into a suitable liquid carrier · □ Edna of the first magnetic fluids has been based on water, in which is dispersed a freshly prepared magnetite (w. C · Elmore Phys. Eq. _T vol 34, 308 (1938). One of the requirements for high-quality magnetic fluid is the particle size of ferromagnetic metal. Until recently, the colloidal particle size has been ensured by milling ferromagnetic ores in ball mills (Khalafalla Z. S. · Chem. Tech., Vol. US 3,215,572). The grinding was energy intensive and took about 1,000 hours.

At present, several methods for the preparation of particles suitable for the production (synthesis) of magnetic liquid are known - from thermal decomposition of ferromagnetic metal salts of organic acids (OP 11 412/61, 22 230/61, 22 394/68) to reduction of ferromagnetic metal oxyhydroxides (GB 1). 192 167, US 3 598 968, 3 681 018) and evaporation of ferromagnetic metal particles in inert gases (OP 27 718/72) to the technologically simple reduction of ferromagnetic metal salts in a suitable solution (OP 20 250/63, 20 116/68 , US 3,106,338, 3,663,318, CS 223,697).

However, the processes for preparing particles by reducing ferromagnetic metal salts in aqueous solution are relatively lengthy in order to remove reaction residues by washing with distilled water, acetone and toluene. In addition, the particles thus prepared have a too wide size distribution, thereby reducing the dispersibility in the liquid carrier. To eliminate these drawbacks, the application of ultrasound, magnetic pole, or the addition of protein or hydrocarbon to the reaction mixture is used during preparation (OP 41 717, 1972, US 4,498,337).

Stabilization of the thus prepared particles in a suitable carrier is achieved by the addition of a fatty acid having a carbon number of 12 to 20. However, the fatty acids themselves are unsuitable or insufficient to produce magnetic liquids with a carrier liquid different from the one-component hydrocarbon metals.

These drawbacks are solved by a magnetic liquid consisting of particles of ferromagnetic metals, stabilizing and dispersing additives and a carrier.

The subject matter of the invention is that the magnetic liquid comprises 0.1 to 20 parts by weight, ferromagnetic metal, 0.1 to 20 parts by weight, fatty acid having a carbon number of 10 to 20 carbon atoms (stabilizer), 0.1 to 20 parts by weight anionic surfactants selected from the group of dialkylsulfosuccinates wherein the alkyl group comprises hydrocarbon radicals having a carbon number of 6 to 20, alkylbenzenesulfates wherein the alkyl comprises hydrocarbon radicals having a carbon number of from 20 to 20 or polyisobutylene succinimides β with a nitrogen content of 0.01 to 10 percent by weight; 100 parts by weight, a liquid carrier selected from the group consisting of form oil MK - CSN 65 6820 on kinematic. viscosity 2-4 mm ² / s, acid number

Claims (4)

5-6 mg KOH / g, kinematic demolding oil. viscosity 5-7 mm ² / e, transformer oil ΙΊΓΌ 100 o kinemat · viscosity 32 mm ² / s, acid number 0,03 mgKOH / g, buffer oil ČSN 65 6890 o kinemat · viscosity 40 mm ² / s, viscosity index 80 , aniline point 75 ° C acid number 0.05 mg KOH / g, glycerine according to No. 3, menthol oil according to No. 3 and refractive index n20 οθ / D · 1.464, density 895 kg / m ³ , pine oil according to No. 3 density 886 kg / m ³ , eucalyptus oil according to MS 3 density 917 kg / m ³ , ref. index n2Q o _c / 0 «« 1,464. The magnetic liquid may be prepared by the method of the invention, wherein the solution of the ferromagnetic metal salts cooled to 15 to 0 ° C is precipitated in 15 seconds with an organic base, an inorganic base or reducing gases with alkali metal hydroxide, hydroxide an alkaline earth metal, metal hydroxide, ammonium hydroxide, hypophosphite, phenol, hydrogen or carbon monoxide cooled to 0-15 ° C. A precipitate is formed which is separated - preferably by magnetic decantation and centrifugation. To 0.1 to 20 parts by weight of the ferromagnetic particles obtained are added 0.1 to 20 parts by weight of a fatty acid having 10 to 20 carbon atoms. The mixture is heated to 90 to 110 ° C and stirred at this temperature with stirring and removal water * preferably by magnetic sedimentation * maintains 4-10 minutes - to form a paste · Anionic surfactant selected from the group consisting of dialkyl sulfosuccinates * alkyl} benzenesulfates * is added to the paste in an amount of 0 * 1 to 20 parts by weight number of carbon atoms 6 to 20 * polyisobutylene succinimides with nitrogen content 0 * 01 to 10 percent by weight * To the mixed mixture is added to 100 parts by weight * liquid carrier from the group: mold * demolding * transformer * buffer * menthol * eucalyptus * pine oil and glycerin * The magnetic liquid according to the invention contains ferromagnetic particles * having a narrowed and less heterogeneous size * for better dispersibility and stability · Simplifies the preparation of the magnetic liquid - a simple precipitation method with a short preparation time * using the technical utility of liquid carriers and effective mixtures of anionic surfactants · This also implies a reduced preparation effort. Example i a) Preparation of paste 1 mol of ferrous sulphate (FeSO ₄ * 7Hg0) and 2 mol of ferric chloride (Fed ₃ * 6 H ₂ 0) are dissolved in 1000 ml of distilled water and the solution is cooled to 5 ° C * The resulting precipitate is magnetically decanted and centrifuged · К 0 * 6 mol of linolenic acid is added to a wet precipitate containing 3 moles of particles * The mixture is heated to 95 ° C with slow stirring and held at this temperature for 4 minutes while removing water by magnetic decantation - until a paste is formed · b) Liquid preparation To 1 g of the paste prepared according to 1 a) 0 * 6 g of 50% sodium dioctylsulfosuccinate * is mixed well with the paste at a homogenizer rotation speed of about 800 min * ¹ and 5 g of eucalyptus oil is added * after thorough mixing to obtain a magnetic liquid based on eucalyptus oil * Example 2 10 g of the polyisobutylene succinimide having a nitrogen content of 1 * 47% per molecule and 10 g of ITO 100 transformer oil are added to 10 g of the paste prepared according to point 1a. After thorough mixing, a magnetic liquid based on transformer oil is obtained * Example 3 To 1 g of oleic acid-stabilized paste prepared according to example 1a, 5 g of sodium dodecylbenzene sulphate is added * After thorough mixing, 1 g of glycerin is added * Example 4 To 1 g of the paste prepared according to Example 1a, 5 g of sodium dioctylsulfosuccinate is added followed by 10 g of pine oil * CS 271544 01 Example 5 For 1 g of the paste prepared according to example 1a and e, 0.1 g of polyisobutylene succininide having a nitrogen content of 2.17% and a subsequent 25 g of molding or demolding oil are added. 0.2 g of sodium dihexylsulfosuccinate and 15 g of menthol oil are added to 1 g of lauric acid-stabilized paste prepared according to Example 1a. after thorough mixing we get a magnetic liquid based on menthol oil · The invention can find application in many fields of engineering practice, such as ore separation, rotary gearbox gaskets, hydraulic equipment manufacturing and the like. OBJECT OF THE INVENTION 1 · Magnetic liquid based on ferromagnetic metal, stabilizer, dispersant and liquid carrier, characterized in that it contains 0.1 to 20 parts by weight of ferromagnetic metal 0.1 to 20 parts by weight of a fatty acid having 10 to 20 carbon atoms as a stabilizer,