RU2808392C1 - Method for producing glass microbeads - Google Patents

Abstract

FIELD: road surfaces.

SUBSTANCE: invention can be used in the production of glass microbeads. A method for producing glass microbeads is claimed, which includes joint grinding of broken moulding materials, moulding of the charge by granulation using a disc granulator and its feeding into the plasma torch of an electric arc plasmatron, the formation of a melt, its dispersion and cooling of the glass microbeads. In this case, lead crystal scrap and high-alumina refractory of grade KL-1.1 are used as cullet for moulding materials. Joint grinding of broken lead crystal and broken high-alumina refractory is carried out at a ratio of 1:1. The mixture is granulated to a granule size of 4.0-6.0 mm. The charge granules are fed into the powder feeder of the electric arc plasma torch, and from it, under the influence of the dynamic pressure of the plasma-forming gas under a pressure of 0.25-0.28 MPa, into the plasma torch. The microbeads are cooled in the exhaust stream of plasma-forming gases.

EFFECT: improving the quality of microbeads.

1 cl, 3 tbl

Description

The invention relates to the field of road surfaces and can be used in the production of glass microbeads.

From the state of the art, methods are known for producing glass microbeads based on silicate glasses, the disadvantage of which is the low wear resistance and microhardness of glass microbeads (Budov V.M., Egorova L.S. Glass microbeads. Application, properties, technology // Glass and Ceramics. 1993. No. 7 pp. 2-5).

The closest solution to the proposed method in terms of technical essence and the achieved result, adopted as a prototype, is a method for producing glass microbeads, including grinding broken crystal and broken porcelain at a ratio of 2:3, molding the charge in the form of granules of 1.0-2.0 mm, feeding the charge into plasma torch of an electric arc plasma torch, melt formation and dispersion (RU Patent No. 2749764, published 06.16.2021, Bulletin No. 17).

The disadvantage of the prototype is its low quality, in particular the low microhardness of the glass microbeads.

The technical result of the proposed invention is to improve the quality of microbeads.

The technical result is achieved by the fact that the method for producing glass microbeads includes joint grinding of broken molding materials, molding of the charge by granulation using a plate granulator and its feeding into the plasma torch of an electric arc plasma torch, the formation of a melt and its dispersion, cooling of glass microbeads, differs in that the quality of the glass microbeads For molding materials, lead crystal cullet and high-alumina refractory grade KL-1.1 are used, while joint grinding of lead crystal cullet and high-alumina refractory cullet is carried out at a ratio of 1:1, the charge is granulated to a granule size of 4.0-6.0 mm, the granules are fed into the powder feeder of the electric arc plasma torch, and from it, under the influence of the dynamic pressure of the plasma-forming gas under a pressure of 0.25-0.28 MPa, into the plasma torch, and the microbeads are cooled in the exhaust stream of plasma-forming gases.

The proposed method differs from the prototype in that:

- joint grinding of broken lead crystal and broken high-alumina refractory grade KL-1.1 is carried out at a ratio of 1:1;

- the mixture is molded into granules measuring 4.0-6.0 mm.

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

The joint grinding of broken lead crystal and broken high-alumina refractory KL-1.1 ensures uniform averaging of the charge. The charge is molded in the form of granules of an optimal size of 4.0-6.0 mm, since when the granule size is less than 4.0 mm, low-quality composite glass microbeads are formed, and when the granule size is more than 6.0 mm, incomplete penetration of the charge occurs and the formation of low-quality glass microbeads microhardness. The supply of granular charge from the powder feeder to the plasma torch must be carried out under the pressure of the plasma-forming gas argon of 0.25-0.28 MPa (productivity 25-30 g/sec), since below or above this threshold value the productivity of obtaining glass microbeads decreases or incomplete melting is observed charge and, as a consequence, obtaining low-quality glass microbeads.

Table 1

Comparative analysis of the known and proposed methods

Suggested method Known method Combined grinding of broken lead crystal and broken high-alumina refractory at a ratio of 1:1

Molding of the charge with the production of granules sized 4.0-6.0 mm

Supply of granules into the powder feeder of an electric arc plasma torch, and from it under the influence of the dynamic pressure of the plasma-forming gas (pressure 0.25-28 MPa) into the plasma torch

Melt formation and dispersion

Cooling of glass microbeads in the exhaust stream of plasma-forming gases

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

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

Supply of granules into the powder feeder of an electric arc plasma torch, and from it under the influence of the dynamic pressure of the plasma-forming gas (pressure 0.25-0.26 MPa) into the plasma torch

Melt formation and dispersion

Cooling of glass microbeads in the exhaust stream of plasma-forming gases

Accumulation of glass microbeads in the collection

Glass microbeads based on broken crystal and broken high-alumina refractory KL-1.1, at the optimal ratio obtained experimentally (Table 2 and 3), have both high microhardness and high refractive index.

table 2

Microhardness and refractive index of composite microspheres

No.
p/p Charge content, mass. % Microhardness, HV Refractive index Lead crystal fight High-alumina refractory scrap KL-1.1 1. 70 thirty 1190 1.53 2. 60 40 1245 1.53 3. 50* 50* 1290* 1.54* 4. 40 60 1238 1.52 5. thirty 70 1199 1.51

* - Optimal option

Table 3

Parameters and properties of microbeads

No.
p/p Parameter name Known method Suggested method 1. Plasma torch UPU-8M UPU-8M 2. Plasma torch GN-5r GN-5r 3. Plasma-forming gas Argon Argon 4. Consumption of plasma-forming gas, g/s 0.00093-0.00163 0.00093-0.00140 5. Current, A 350-450 350-450 6. Voltage, V thirty thirty 7. Gas pressure in the powder feeder, MPa 0.25-0.26 0.25-0.26 8. Productivity, g/sec 8-10 25-30 9. Microbead size, microns 900-2100 1800-2300 10. Composition of the initial charge The fight of crunchy lead and the fight of porcelain
glass - 40%;
farrfor-60% Scrap of lead crystal and scrap of high-alumina refractory KL-1.1:
glass – 50%;
alumina – 50%. eleven. Microhardness, HV 1045 1290 12. Refractive index 1.53 1.54

Example

Broken lead crystal and broken high-alumina refractory grade KL-1.1 were placed in a porcelain ball mill at a ratio of 1:1 parts by weight, respectively, which corresponded to 50% (5 kg) broken crystal and 50% (5 kg) broken high-alumina refractory grade KL-1 ,1. Co-grinding was carried out for 2 hours. Urolith balls served as grinding bodies. Using a laboratory disc granulator, the mixture was granulated to obtain granules with a size of 4.0-6.0 mm. Then the plasma torch GN-5r of the electric arc plasma torch UPU-8M was ignited. The operating parameters of the plasmatron are as follows: current 450A, voltage 30V, plasma gas flow rate 0.00140 g/s. Water consumption for cooling is 10 l/min.

The granulated mixture was loaded into a powder feeder. From the powder feeder under a pressure of 0.25 MPa it entered the GN-5r plasma torch. Under the influence of high plasma temperatures in the plasma torch, the granular charge melted with the formation of melt drops. During the cooling process, crystallization of alpha and beta modifications of aluminum oxide occurred in the melt droplets, uniformly distributed throughout the entire volume. Alpha and beta modifications of aluminum oxide provide high hardness of microspheres. Lead oxide in the composite microsphere provided a high refractive index.

Spontaneous cooling of the composite microspheres occurred in the flow of exhaust plasma-forming gas. The average size of microspheres was in the range of 1800-2300 µm.

The microhardness of composite microspheres was determined using a Vickers microhardness tester as the average of five measurements:

HV = (1288+1292+1290+1291+1289) /5 = 1290 HV.

Claims (1)

A method for producing glass microbeads, including joint grinding of broken molding materials, molding of the charge by granulation using a plate granulator and its supply to the plasma torch of an electric arc plasma torch, formation of a melt and its dispersion, cooling of glass microbeads, characterized in that lead crystal scrap is used as cullet of molding materials and high-alumina refractory grade KL-1.1, while joint grinding of broken lead crystal and broken high-alumina refractory is carried out at a ratio of 1:1, the charge is granulated to a granule size of 4.0-6.0 mm, the granules are fed into the powder feeder of an electric arc plasmatron, and from it, under the influence of the dynamic pressure of the plasma-forming gas under a pressure of 0.25-0.28 MPa, into the plasma torch, and the microbeads are cooled in the exhaust stream of plasma-forming gases.