RU2183994C2 - Method for grinding high-strength rock - Google Patents

Abstract

FIELD: mining industry. SUBSTANCE: method involves two or more grinding stages; screening ground products on screens and returning oversized material for additional grinding in closed cycle combined with screening; obtaining grains of isometric shape approximating cubic shape by granulating small-sized fractions of crushed stone (from 3 mm to 20 mm) produced at stages preceding fine grinding stage in fine grinder in layer of oversized material. EFFECT: increased efficiency of multiple stage grinding process. 3 cl, 3 dwg

Description

 The invention relates to the building materials industry and can be used in the production of high-quality aggregates of concrete, asphalt concrete and other products, where they are subject to grain shape requirements.

 A known method of producing crushed stone of small fractions from 5 to 10 mm and more than 10 to 20 mm from the rock mass of high-strength rocks such as granites, diorites, basalts, etc. (see. Norms of technological design of industrial enterprises of non-metallic building materials, L .: Stroyizdat, 1977, p. 290, Fig. 24).

 The method involves crushing the rock mass, as a rule, in three stages, including large, medium and small crushing using jaw and cone crushers, and a closed cycle after fine crushing, while the resulting crushed stone, as a rule, does not meet the requirements.

 The invention closest in technical essence is a crushing method for producing small gravel of one or several fractions from high-strength rocks, including two or more crushing stages, sieving on the screens of crushing products and returning to completion of the over-dimensional material in a closed cycle with a roar.

 The disadvantage of this method is the low quality of crushed stone.

 The objective of the invention is to increase the efficiency of the multi-stage process of crushing high-strength abrasive rocks in the production of high-quality small (up to 20 mm) aggregates of concrete and asphalt concrete with an isometric (cuboid) shape of grains.

 This problem is achieved in the method of crushing upon receipt of small gravel of one or several fractions from high-strength rocks, including two or more stages of crushing, sieving on the screens of crushing products and returning to completion of the over-dimensional material in a closed cycle with a roar, obtaining grains of an isometric shape close to cuboid, carried out by granulation in a crusher of fine crushing, in a layer of oversized material, of fine fractions of crushed stone in the range from 3 to 20 mm obtained on the previous ones to a fine crusher ny stages.

 To obtain fine gravel of fractions from 3 to 20 mm with an isometric shape of grains, sand fractions of 0-3 mm, fine gravel of fractions from 3 to 20 mm, marketable gravel of fractions from 20 are separated from crushed material obtained at the stages preceding fine crushing up to 40 mm and extra-dimensional material with grains larger than 40 mm, then fine crushed stone and excess material are combined and sent as a mixture to fine crushing, and commodity fractions of crushed stone and sand are sent to the warehouse.

 To simplify the technological scheme of crushing, crushed fractions from 20 to 40 mm are extracted from crushed material obtained after the crushing stages preceding small crushing, and material with grains up to 20 mm and more than 40 mm in size is combined and sent to fine crushing.

 In FIG. 1 shows a diagram of the production of small gravel for implementing the method; figure 2 is the same (option); figure 3 is the same (option).

 The initial mass enters the crusher medium crushing, for example, in a jaw crusher (see figure 1). The crushed material is conveyor 2 sent to the crusher medium crushing 3, for example, in a cone crusher. The product of the middle conveyor by conveyor 4 is sent to a screen for sieving 5 mm grain. In this case, the screen is equipped with one or more screens. The under-sieve product of the lower sieve - a fraction from 0 to 5 mm - conveyor 6 is sent to the finished goods warehouse. Oversize (e) product (s) - a fraction of more than 5 mm - are sent to a fine crusher 7, for example, a cone crusher. Crushed material is sent to the screen 8, equipped with sieves with cells 5x5, 10x10 and 20x20 mm. Screening products: sand from crushing screenings from 0 to 5 mm, crushed stone from 5 to 10 and St. 10 to 20 mm are sent to the warehouse by conveyors 9, 10 and 11 (respectively), and oversized material (+20 mm) is returned for completion by conveyor 12 to the crusher.

 When releasing fractions from 5 to 20 mm of larger crushed stone, along with small gravel, for example, fractions of st. 20 to 40 mm (see figure 2), the screen 5 is equipped with sieves with cells 5x5, 20x20 and 40x40 mm. In this case, the finished product: a fraction from 0 to 5 mm and crushed stone of a fraction of sv. 20 to 40 mm are sent to the warehouse by conveyors 6 and 13, respectively, and crushed stone of a fraction of 5 to 20 mm and oversized material (+40 mm) are combined and sent to fine crushing into a crusher 7.

 In order to simplify the process (see figure 3), the screen 5 is supplied only with sieves with cells 20x20 and 40x40 mm. The finished product - crushed stone of the fraction sv. 20 to 40 mm is conveyed by 6 to the warehouse, and the under-sieve material of the lower sieve (0-20 mm) is combined with the over-sieve material of the upper sieve (+20 mm) and sent to fine crushing in the crusher 7.

 When changing the size of fractions of crushed stone in the finished product in the range from 3 to 20 mm, respectively, change the size of the mesh sieves on screens.

 The economic efficiency of producing fine high-quality crushed stone with an isometric (or close to) grain form using this crushing method is achieved by increasing the efficiency of using fine crushers.

Claims (3)

 1. The method of crushing upon receipt of small gravel of one or more fractions from high-strength rocks, including two or more stages of crushing, sieving on the screens of crushing products and returning to completion of the over-dimensional material in a closed cycle with a screen, characterized in that the production of isometric-shaped grains, close to cuboid, they are carried out by granulation in a crusher of fine crushing in a layer of super-dimensional material of fine fractions of crushed stone in the range of 3 - 20 mm obtained in the stages preceding fine crushing.  2. The crushing method according to claim 1, characterized in that in order to obtain fine gravel of fractions of 3-20 mm with an isometric shape of grains from crushed material obtained in the stages preceding fine crushing, sand fractions of 0-3 mm, fine gravel of fractions are isolated on screens 3 - 20 mm, marketable crushed stone of fractions 20 - 40 mm and super-dimensional material with grains larger than 40 mm, then small crushed stone and super-dimensional material are combined and sent as a mixture to fine crushing, and commercial fractions of crushed stone and sand are sent to the warehouse.  3. The crushing method according to claim 1, characterized in that, to simplify the technological scheme of crushing, crushed fractions of 20-40 mm are extracted from crushed material obtained after the crushing stages preceding fine crushing, and material with grains up to 20 mm and over 40 mm are combined and sent to fine crushing.

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