RU2442657C1 - Method of production of nanosized particles of the mineral shungite - Google Patents

Abstract

FIELD: milling technologies.

SUBSTANCE: invention relates to the technology of the mineral shungite milling to the effect of receiving of nanosized particles used as an active filler in production of elastomeric compounds; the mineral shungite is taken as a basic sample with the size of microparticles of 0÷100 micron, grinding is executed in the planetary ball mill loading into the grinding bowl the basic components in the proportion from 1.5:1:1.5 to 2.5:1:3 by volume: basic shungite - branched spirit - milling balls with the diameter 0.5÷5 mm; the milling processes is performed with adding of the branched spirits with the number of the carbon atoms not more than eight, at that the (OH) group is located not at the outmost carbon atom; the temperature of the basic mixture does not exceed 150°C and the milling process is executed in the grinding bowl located on the planetary disc of the planetary ball mill at the speed of 100÷700 revolutions per minute reversing rotation every 5÷10 minutes within up to 6 hours of the nonstop milling process; the grinding bowl is revolving about its axis but in the opposite direction relatively the rotation of the planetary disc securing the multiple increase of the milling energy and smaller particles sizes thereby; after milling the shungite to the size of particles within the limits of 5÷50 nm the substance is dried in the drying box during 0.5÷6 hours at the temperature of about 80÷250°C and thereafter the milled mineral is packaged into airtight containers.

EFFECT: application of this method allows to provide the elastomeric compounds incorporating shungite as the active component with high mechanical and operation characteristics.

5 cl, 3 dwg, 2 tbl

Description

The invention relates to a technology for processing natural raw materials, namely shungite mineral, in order to obtain a powder with nanosized particles, which can be used, inter alia, as an active filler for the manufacture of elastomeric composites used in various rubber products, as well as in automotive oil refining, light industry, in construction, in the manufacture of tire parts, etc.

A known method of processing materials, including feeding material with water into an annular grinding zone from above, volumetric compression of the material in the grinding zone, abrasion of the material particles one by one by forced polygradient movement of the concentric layers of the material with simultaneous pulsed action on the particles at the time of their deformation and destruction by a high-temperature liquid flow superheated steam or hot air, mixing the crushed product with cold water and removing the pulp from below; while the supply of material with water (surfactant solution) in an annular grinding zone and mixing the crushed product with water is carried out after preliminary electrochemical treatment of the water (surfactant solution) supplied to the grinding process in the electrolyzer [1].

This technical solution is used when grinding ore or nonmetallic raw materials to such a state of the surface of the particles of the useful component so that they can then be effectively extracted by physicochemical methods of enrichment. At the same time, the particles of the processed material are crushed by the method of abrasion to their powder state, but not to micro- and nanoscale particles, i.e., this method, when applied to the grinding of the mineral, schungite will not allow an active filler with the subsequent production of an elastomeric composite with a high complex of mechanical and operational characteristics.

Methods for modifying the shungite mineral by various combination agents are also known [2].

However, these methods also do not allow shredding of the schungite mineral to a particle size of the order of (5-50) nm, that is, to nanoscale particles. As a result, the use of such shungite as an active filler in the production of elastomeric materials will not provide high mechanical properties of the manufactured material, due to the low specific surface of the original shungite. In this case, the chemical modification of the inactive filler does not lead to the production of elastomeric materials with a complex of high performance characteristics.

The applicant set himself the technical task of obtaining a powder of shungite mineral with nanosized particles for the manifestation of their enhancing effect in an elastomeric composite material that is filled with particles of shungit mineral nanosized, providing a set of high performance characteristics of the manufactured material. The technical result of the application of a new method of grinding shungite mineral is to obtain a powder of this mineral with particles of medium size in the range from 5 nm to 50 nm, that is, particles of nanoscale. The specified technical result was achieved due to the combination of essential features of a new method for producing nanosized particles from shungite mineral, given in the following claims: “a method for producing nanosized particles from schungite mineral, including preparation of the initial fraction of shungite mineral with any ratio of silicon / carbon (Si / C) and microparticles with sizes from 0 to 100 microns and the implementation of the process of grinding shungite in a planetary ball mill, while in a grinding bowl of a planetary ball the mills load the initial components of shungite - alcohol - grinding elements with a diameter of (0.5 ÷ 5) mm and in a ratio of (1.5: 1: 1.5) to (2.5: 1: 3) by volume, respectively moreover, alcohol is taken as alcohol from a number of branched alcohols with the number of carbon atoms no more than eight, the oxygen-hydrogen (OH) group of which is not located at the extreme carbon atom, but as grinding elements designed to prevent the formation of large agglomerates and reduce heat during grinding use balls or other balls nye the grinding elements are made of the same material as the grinding bowl; the grinding process of the above initial fraction of shungite mineral is carried out at a temperature not exceeding 150 ° C, the rotation speed of the planetary disk on which the grinding cup of the planetary ball mill is installed, within 100 ÷ 700 rpm, while the grinding cup rotates around its vertical axis, but in in the opposite direction of rotation of the planetary disk, which accelerates this action due to the centrifugal force and the Coriolis force, with a reverse every 5 ÷ 30 minutes and a time not exceeding six hours of continuous process grinding cassette, then crushed shungite is dried in an oven for 0.5 ÷ 6 hours at a temperature of 80 ÷ 250 ° C and sealed in a container of shungite mineral with an average particle size of 5–50 nm, characterized by a specific surface for multi-point adsorption nitrogen ≥ (70 ÷ 80) m ² / g and providing high nominal stresses in the composition of elastomeric composites up to 11 MPa with a relative elongation of 300% and their strength within (15 ÷ 16) MPa; Shungite fractions of 0 ÷ 5 microns are used as starting material; a grinding cup of a planetary ball mill is made of tungsten carbide with a volume of 250 ml; isopropyl alcohol C ₃ H ₇ OH (2-propanol) is added to the grinding bowl of a planetary ball mill with schungite powder; as grinding elements when grinding shungite particles, small steel balls with a diameter of 3 mm are used; the ratio of the rotational speeds of the grinding bowl and the planetary disk of the planetary ball mill is 1: 2. "

The invention works as follows.

Shungite mineral with any ratio of silicon / carbon content (Si / C) and microparticle sizes from 0 to 100 microns or shungite mineral with properties similar to this sample are taken as the initial sample. To grind (grind) the mineral shungite, a planetary ball mill is used, for which the initial components are loaded into its grinding bowl in the ratio: initial shungite - branched alcohol - grinding balls with a diameter of (0.5 ÷ 5) mm from (1.5: 1: 1 5) up to (2.5: 1: 3) by volume, respectively. The grinding process is carried out in a liquid state in order to achieve submicron or colloid-sized particles. For this purpose, alcohols are used that contribute to the better grinding of shungite, prevent the formation of large agglomerates and reduce heat during grinding, while mainly branched alcohols with the number of carbon atoms no more than eight are chosen, the oxygen-hydrogen (OH) group of which is not at the extreme carbon atom. The presence of a liquid (alcohol of the selected type) also leads to better dispersion and, thus, reduces the amount of agglomerates of smaller particles that interfere with the grinding. The grinding temperature of the initial mixture does not exceed 150 ° C. The grinding process is carried out in a grinding bowl mounted on the planetary disk of a planetary ball mill at a speed of (100 ÷ 700) rpm with a reverse every (5 ÷ 10) minutes for up to six hours of a continuous grinding process. With the rotation of the planetary disk, the grinding bowl rotates around its vertical axis, but in the opposite direction. This action is rapidly accelerated due to the centrifugal force and Coriolis force. As a result, the grinding energy increases many times, which makes it possible to achieve smaller particle sizes. In addition, the rapid acceleration of shungite particles from one edge of the grinding bowl to the other resulting from such planetary rotation leads to a strong interaction between the grinding balls and material samples (shungite fraction), while providing an additional grinding effect from frictional forces.

After grinding, drying is carried out in an oven for 0.5 ÷ 6 hours at a temperature of 80 ÷ 250 ° C and sealed packaging of shungite mined mineral is carried out in a container.

The proposed method is illustrated by the example of grinding the shungite mineral of the Novokarbon trademark produced by Karbon-Shungit Trade LLC, TU 2169-001-57753937-2002, fraction 0-5 microns.

Shungite mineral was grinded in a wet planetary ball mill with the addition of C ₃ H ₇ OH isopropyl alcohol (2-propanol, TU 232-015-11291058-95). The addition of isopropyl alcohol improves the process of grinding shungite due to its better dispersion, eliminates the formation of large agglomerates, reduces heat during grinding, and also reduces the heating of the grinding bowl. The initial components for the shungite mineral grinding process were loaded in the ratio: initial shungite - isopropyl alcohol - grinding balls by volume, respectively. As a result, the load looked like this: 100 ml of shungite, 50 ml of isopropyl alcohol and 120 cm ^{3 of} small steel balls with a diameter of 3 mm. The use of small balls actually reduces the effect of agglomerates of smaller particles and allows friction forces to participate in the grinding process, that is, when shungite particles become smaller, they are less and less subject to splitting. The grinding temperature did not exceed 85 ° C. Grinding was carried out at a speed of 500 rpm of the planetary disk with a ratio of its rotation speed and the rotation speed of the grinding bowl of the planetary ball mill, equal to 1: 2. Every 15 minutes, the rotation of the planetary disk and the grinding bowl was reversed. The volume of the grinding cup made of tungsten carbide was 250 ml. The grinding time was 2 hours. Then, shredded shungite was dried for 2 hours in an oven at a temperature of 200 ° C and, after a control analysis of the obtained particles of mineral shungite of nanoscale size, in comparison with the initial fraction, it was hermetically packed in a prepared container.

The results of the control comparative analysis of the size of the crushed particles of shungite mineral are presented in the figures, where in Fig. 1 is a graph of the distribution of particle sizes for the initial fraction of shungite mineral; figure 2 is a graph of the distribution of particle sizes for the crushed mineral shungite according to the present invention; figure 3 - particle size distribution for the crushed mineral shungite according to the present invention, obtained by processing an AFM image of an agglomerate of particles of crushed schungite in the SPIP program.

To confirm the effectiveness of the shungite mineral crushed by the proposed method in elastomeric composites as a reinforcing filler, which significantly increases the set of physicomechanical properties of the elastomeric composite, the Applicant tested these composites with the initial and crushed schungite mineral according to the present invention, the results of which are shown in the following tables :

Table 1 The main properties of the mineral shungite of various degrees of grinding Type of mineral shungite Density kg / m ³ Surface area by multipoint nitrogen adsorption D4820, m ² / g Bulk density, kg / m ³ The average particle size, nm pH of an aqueous suspension, units pH Source fraction 2,4 16 250 200 5.2 Shredded 2,4 80 370 5-50 6.6

table 2 The main physical and mechanical characteristics of elastomeric materials filled with 65 wt. parts of shungite mineral of various degrees of grinding Indicators Dimension Sample Number one 2 Elongation 100% MPa 2.0 2.7 Elongation stress 200% MPa 3.3 5.8 Elongation stress 300% MPa 4,5 11.0 Conditional tensile strength MPa 5,6 15,2 Relative extension % 390 360 Residual elongation % 8.0 12.0 Tear resistance kN / m 18.0 25.9 Specific work of deformation on the destruction of the sample MJ / m ³ 12.3 22.4 Relative hysteresis (1st cycle) % 14,4 17.0 Relative hysteresis (20th cycle) % 4.7 7.1 1 - initial sample of shungite mineral 2 - shungite mineral, crushed to particles of nanoscale sizes

Information sources

1. Description of the invention to the patent of the Russian Federation No. 2104787 "Method for the processing of materials", B02C 17/02. Announced on 08/07/96; Published on 02/20/98; Bulletin No. 5.

2. Kovaleva A.N., Kandyrin K.L., Potapov E.E. “Modification of schungite by various combination agents” - abstracts of the VIII Annual International Youth Conference of the IBCF RAS - Universities “Biochemical Physics”, November 11–13, 2008, Moscow, pp. 107-108.

Claims (6)

1. A method of producing particles of nanoscale minerals from shungite mineral, which includes preparing the initial fraction of shungite mineral with any ratio of silicon / carbon (Si / C) and microparticles with sizes of 0 ÷ 100 microns and the implementation of the process of grinding shungite in a planetary ball mill, while in a grinding bowl planetary ball mill load the initial components in the composition of shungite - alcohol - grinding elements with a diameter of 0.5 ÷ 5 mm in a ratio of from 1.5: 1: 1.5 to 2.5: 1: 3 by volume, respectively, and as alcohol take branched alcohol of alcohols with the number of carbon atoms no more than eight, the oxygen-hydrogen (OH) group of which is not located at the extreme carbon atom, but as grinding elements designed to prevent the formation of large agglomerates and reduce heat during grinding, use balls or other spherical grinding elements made from the same material as the grinding bowl, the grinding process of the above-mentioned initial fraction of schungite mineral is carried out at a temperature not exceeding 150 ° C, planetary rotation speed of the first disk on which the grinding bowl of the planetary ball mill is installed, within 100 ÷ 700 rpm, and at the same time rotating the grinding bowl around its vertical axis, but in the opposite direction to the rotation of the planetary disk, which accelerates this action, thanks to the centrifugal force and the Coriolis force , with a reverse every 5 ÷ 30 min and a time not exceeding six hours of a continuous grinding process, then the crushed schungite is dried in an oven for 0.5 ÷ 6 hours at a temperature of 80 ÷ 250 ° C and tightly packaging containers mineral shungite with an average size of crushed particles is 5 ÷ 50 nm, characterized by a specific surface area by multipoint nitrogen adsorption ≥ (70 ÷ 80) m ² / g, and providing in the composition of the elastomeric composite high values of the conditioned voltage to 11 MPa with an elongation of 300% and their strength within 15 ÷ 16 MPa. 2. The method according to claim 1, in which the starting material is shungite fraction 0 ÷ 5 μm. 3. The method according to claim 1, in which the grinding cup of a planetary ball mill is made of tungsten carbide with a volume of 250 ml. 4. The method according to claim 1, in which isopropyl alcohol C ₃ H ₇ OH (2-propanol) is added to a glass of a planetary ball mill with schungite powder. 5. The method according to claim 1, in which small steel balls with a diameter of 3 mm are used as grinding elements when grinding shungite particles. 6. The method according to claim 1, in which the ratio of the rotational speeds of the grinding bowl and the planetary disk of the planetary ball mill is 1: 2.

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