BG67246B1 - Method for regeneration of abrasive material, cryolite and glass mesh of abrasive discs - Google Patents

Abstract

The invention relates to a method for regeneration of abrasive material, cryolite and glass mesh from abrasive discs and their reuse and finds application in construction, mechanical engineering, as well as all areas of industry where the use of cutting discs is required. The method is applicable to abrasive discs using as a binder both bakelite and polyurethane and any other type of organic binder, as meanwhile the size of the abrasive particles remains unchanged and their efficiency is maintained accordingly.

Description

(54) METHOD FOR REGENERATION OF ABRASIVE MATERIAL, CRYOLITE AND GLASS NET OF ABRASIVE DISCS

Field of technology

The invention relates to a method for regeneration of abrasive material, cryolite and glass mesh from abrasive discs and their reuse and finds application in construction, mechanical engineering, as well as all areas of industry where the use of cutting discs is required.

BACKGROUND OF THE INVENTION

Abrasive discs are used for cutting reinforcement, profile pipes, steel angles, channel rods, sheet steel. The base of the metal disc consists of two layers of fiberglass (glass mesh), on which a mass of abrasive materials is applied: corundum (alumina) or silicon carbide, in the form of grains, or electrocorundum. The technology for the production of abrasive discs involves heat treatment, after which the product gains strength. The production of abrasive discs is accompanied by about 5-10% waste. Given the high cost of abrasives and glass mesh, their regeneration is an economically important issue. To date, methods for recycling and using discarded and used abrasive discs have been disclosed in the literature by: melting the binder-polyurethane foam (US Pat. 5344472, 1994); mechanical crushing, screening and purging (WO 1998/010895 (1996)).

Revealed in US pat. 5344472, 1994 a method for recycling abrasive discs by melting the binder has the following disadvantages: (i) it is only applicable to abrasive discs in which polyurethane is used as the binder; (p) the abrasive material is not separated from the cryolite; (ni) the glass mesh is not regenerated.

The method known from WO 1998/010895 (1996) for the regeneration of abrasive discs by mechanical crushing, sieving and blowing also has a number of disadvantages: (i) the regenerated abrasive material as a result of mechanical crushing changes the particle size, which is decisive for its efficiency; (j) it is necessary to remove the glass mesh, which is also broken; (iii) the mechanically crushed abrasive material will also contain the organic binder - bakelite.

No data have been found in the literature for a method for simultaneous regeneration of abrasive materials, cryolite and glass mesh of abrasive discs, in which the size of the abrasive particles remains unchanged, the glass mesh retains its characteristics while removing the binder such as bakelite or polyurethane.

Technical essence of the invention

The object of the invention is to provide a method for the regeneration of abrasive materials corundum, silicon carbide in the form of grains, cryolite, which is a double salt of sodium fluoride and aluminum fluoride Na ₃ AlF ₆ and is used as an active filler in the production of abrasive discs and glass mesh (fiberglass) applicable to abrasive discs using both bakelite and polyurethane foam and any other organic binder as a binder, while the size of the abrasive particles remains unchanged and their efficiency is maintained accordingly.

The problem was solved by creating a method for regeneration of abrasive materials, cryolite and glass mesh of abrasive discs, including the operations of preparation of abrasive discs for regeneration by

BG 67246 Bl string the discs on heat-resistant skewers and place them in a heated pyrolysis furnace. According to the invention, the method also includes the following operations:

- pyrolysis of the abrasive discs in the temperature range 550-800 ° С;

- pyrolysis from 25 to 30 minutes;

- cooling of the regenerated material from 30 to 60 min.

The proposed method quantitatively regenerates the abrasive material, cryolite and glass mesh. Pyrolysis in the temperature range of 550-800 ° C completely decomposes the organic binder, preserving the abrasive material, the glass mesh and the cryolite.

After the mechanical separation of the regenerated abrasive material, cryolite and glass mesh, they have the same properties as the starting materials used and can be reused.

The method is also applicable to abrasive discs in which polyurethane is used as a binder, as well as any other type of organic binder.

The advantages of the invention are: (i) the abrasive material is regenerated almost quantitatively (-95%) while retaining its performance characteristics; (I) the glass mesh is quantitatively regenerated (100%) and can be reused in the production of abrasive discs; (iii) the regenerated cryolite retains its performance characteristics and can be used in the production of abrasive discs. The regeneration method is easy to implement and economical to implement.

An exemplary embodiment of the invention

Example

Metal-to-metal abrasive disc, A 24, weighing 262 g, containing alumina, in the form of grains, glass mesh two pieces, cryolite and a binder - bakelite, was placed in an oven. The furnace was heated to 650 ° C for about 30 minutes. The sample was kept at this temperature for 30 minutes (pyrolysis time), after which the heating of the furnace was switched off. After cooling the furnace and the regenerated abrasive material for 30 to 60 minutes, it was found that the disk was completely degraded. The glass mesh is completely preserved. The residue after decomposition is the abrasive material - alumina, glass mesh and gray cryolite powder. The recovered materials have the same properties as the starting materials used and can be reused.

Claims (1)

A method of regenerating abrasive materials selected from the group consisting of corundum, silicon carbide or electrocorundum in the form of particles, cryolite and a glass mesh of abrasive discs, comprising the following operations: - preparation of the abrasive discs for regeneration by stringing the discs on heat-resistant skewers and placing them in a pyrolysis furnace heated to a temperature of 550 ° С-800 ° С; - pyrolysis of the abrasive discs in the temperature range 550 ° С-800 ° С; - retention of the regeneration material in the furnace for a period of 25 to 30 minutes; - switching off the heating of the furnace and cooling of the obtained material from 30 to 60 min.