RU2749764C1 - Method for producing composite micro-balls - Google Patents

Abstract

FIELD: road construction.

SUBSTANCE: invention relates to the field of producing micro-balls, it can be used in road construction. The method for producing composite micro-balls includes grinding the breakage of molding materials, forming the charge and feeding it into the plasma burner of an electric arc plasma torch, forming the melt and its dispersion, cooling the micro-balls, accumulating micro-balls in the collection. Broken lead crystal and broken porcelain are used as the breakage at a ratio of 2:3. The charge is formed in the form of granules with a size of 1.0-2.0 mm. The granules are fed into the powder feeder of an electric arc plasma torch, and from it, under the action of the dynamic pressure of the plasma-forming gas (pressure 0.25-0.26 MPa) into the plasma burner. The micro-balls are cooled in the outgoing flow of plasma-forming gases.

EFFECT: proposed is production of micro-balls with high micro-hardness.

1 cl, 3 tbl

Description

The invention relates to the field of road surfaces and can be used to obtain microbeads.

Methods for producing microspheres based on silicate glasses are known from the prior art, the disadvantage of which is the low microhardness of the microspheres.

The closest solution to the proposed method in terms of the technical essence and the achieved result is a method for producing microspheres from high-quality glasses, including grinding cullet, forming a charge with the manufacture of rods, feeding them into the plasma torch of an electric arc plasmatron, forming and dispersing the melt, gradual cooling of microspheres in the flow of outgoing plasma-forming gases, and then, when they come into contact with a water-cooled metal hemisphere, the supply of microbeads to a vibrating sieve and the accumulation of microbeads in the collector. [Bessmertny V.S., Krokhin V.P., Lyashko A.A., Dridge N.A., Shekhovtsova Zh.E. Obtaining glass microspheres by plasma spraying // Glass and ceramics. 2001, No. 8. - from. 6-7].

The disadvantage of the prototype is the low microhardness of the microspheres.

The technical result of the proposed invention is to obtain microspheres with high microhardness.

The technical result is achieved by the fact that The method for producing composite microbeads includes crushing the breakage of molding materials, forming a charge and feeding it into the plasma torch of an electric arc plasmatron, forming a melt and dispersing it, cooling the microspheres, accumulating microspheres in the collection, and as breakage, breakage of lead crystal and breakage of porcelain is used at a ratio of 2: 3, the charge is molded in the form of granules with a size of 1.0-2.0 mm, the granules are fed into the powder feeder of the electric arc plasmatron, and from it, under the action of the dynamic pressure of the plasma-forming gas (pressure 0.25-0.26 MPa), into the plasma torch, cooling microspheres are performed in the exhaust stream of plasma gases.

The proposed method differs from the prototype in that:

- as a battle, the battle of lead crystal and the battle of porcelain are used at a ratio of 2: 3;

- the charge is formed in the form of granules with a size of 1.0-2.0 mm;

- the granules are fed into the powder feeder of the electric arc plasmatron, and from it, under the action of the dynamic pressure of the plasma-forming gas (pressure 0.25-0.26 MPa), into the plasma torch;

- the cooling of the microspheres is performed in the exhaust flow of the plasma-forming gases.

A comparative analysis of the known and proposed methods is presented in table 1.

Combined grinding of broken crystal and broken porcelain ensures uniform averaging of the charge. The charge is formed in the form of granules of the optimal size of 1.0-2.0 mm, since when the granule size is less than 1.0 mm, composite microspheres of low quality are formed, and when the granule size is more than 2.0 mm, incomplete penetration of the charge occurs and the formation of microspheres with low microhardness. The supply of the granular charge from the powder feeder to the plasma torch must be carried out under the pressure of the plasma-forming argon gas 0.25-0.28 MPa (productivity 10-12 g / s), since below or above this threshold of values, the productivity of obtaining microspheres decreases or incomplete melting is observed charge and, as a consequence, the production of low quality microspheres.

Table 1
Comparative analysis of known and proposed methods The known method The proposed method

Подача стержней в плазменную горелку электродугового плазмотрона

Образование расплава и его диспергация

Постепенное охлаждение микрошариков в отходящем потоке плазмообразующих газов, а затем при их соприкосновении с водоохлаждаемой металлической полусферой

Подача микрошариков на вибросито

Накопление микрошариков в сборникеCullet crushing

Charge molding with the production of rods

Feeding rods to the plasma torch of the electric arc plasmatron

Melt formation and dispersion

Gradual cooling of microspheres in the exhaust flow of plasma gases, and then, when they come into contact with a water-cooled metal hemisphere

Feeding micro beads on a vibrating sieve

Accumulation of microspheres in the collection Combined grinding of broken lead crystal and broken porcelain at a ratio of 2: 3

Forming a charge with the production of granules with a size of 1.0-2.0 mm

Supply of granules to the powder feeder of the electric arc plasmatron, and from it under the action of the dynamic pressure of the plasma-forming gas (pressure 0.25-0.28 MPa) into the plasma torch

Melt formation and dispersion

Cooling of microspheres in the exhaust stream of plasma gases

Accumulation of microspheres in the collection

Composite microspheres based on crystal breakage and porcelain breakage at the optimal ratio obtained experimentally (tables 2 and 3) have both high microhardness and refractive index.

table 2
Microhardness and refractive index of composite microspheres No.
p / p Charge content, wt. % Microhardness, HV Refractive index Lead crystal break Fight porcelain one. 70 thirty 850 1.53 2. 60 40 1045 1.53 3. fifty fifty 1060 1.33 four. 40 60 1085 1.52 five. thirty 70 1099 1.51 Table 3
Parameters and properties of microspheres No.
p / p Parameter name The known method The proposed method one. Plasmatron UPU-8M UPU-8M 2. Plasma torch GN-5r GN-5r 3. Plasma gas Argon Argon four. Plasma-forming gas consumption, g / s 0.00093-0.00163 0.00093-0.00140 five. Current, A 350-450 350-450 6. Voltage, V thirty thirty 7. Gas pressure in the powder feeder, MPa - 0.25-0.26 eight. Productivity, g / sec * 2-3 * 8-10 * nine. Microspheres size, microns 80-1450 900-2100 10. The composition of the initial charge Breakage of high-quality glasses - 100% The battle of lead crystal and the battle of porcelain:
glass - 40%;
porcelain - 60%. eleven. Microhardness, HV * 560 * 1045 * 12. Refractive index, and * 1.51 * 1.53 *

* - according to our own research.

Example.

Broken lead crystal and broken porcelain were placed in a porcelain ball mill at a ratio of 2: 3 parts, respectively, which corresponded to 40% broken crystal and 60% broken porcelain. Joint grinding was carried out within 2 hours. Urolite balls were used as grinding bodies. Using a laboratory tray granulator, the charge was granulated to obtain granules of 1.0-2.0 mm. Then the plasma torch GN-5r of the UPU-8M electric arc plasmatron was ignited. The operating parameters of the plasmatron are as follows: current 450A, voltage 30V, plasma-forming gas flow rate 0.00140 g / s. Cooling water consumption 10 l / min.

The granular mixture was loaded into a powder feeder. From a powder feeder under a pressure of a plasma-forming argon gas of 0.26 MPa, charge granules with a diameter of 1.0-2.0 mm were fed into a GN-5r plasma torch. Under the action of high plasma temperatures in the plasma torch, the granular charge melted with the formation of melt droplets. During the cooling process, secondary mullite was formed in the droplets of the melt, uniformly throughout the volume. Mullite provided high microhardness of composite microspheres. Lead oxide in the composition of the composite microsphere provided a high refractive index.

Spontaneous cooling of the composite microspheres occurred in the flow of the exhaust plasma-forming gas. The average size of the microspheres was in the range of 900-2100 microns.

The microhardness of composite microspheres was determined using a Vickers microhardness tester as the average of five measurements: HV = (1026 + 1076 + 1052 + 1037 + 1045) / 5 = 1045, 2 HV

Claims (1)

A method for producing composite microbeads, including crushing molding materials breakage, forming a charge and feeding it into a plasma torch of an electric arc plasmatron, forming a melt and dispersing it, cooling microspheres, accumulating microbeads in a collection, characterized in that lead crystal breakage and porcelain breakage are used as breakage at a ratio of 2: 3, the charge is formed in the form of granules with a size of 1.0-2.0 mm, the granules are fed into the powder feeder of the electric arc plasmatron, and from it, under the action of the dynamic pressure of the plasma-forming gas with a pressure of 0.25-0.26 MPa, into the plasma the burner, the cooling of the microspheres is performed in the exhaust stream of the plasma-forming gases.