RU2251457C1 - Installation for disintegrating and classifying high-rigidity materials such as metallic chrome - Google Patents

Abstract

FIELD: disintegration and classifying processes and equipment.

SUBSTANCE: installation includes hopper for initial material, ventilated ball mill provided with gravitation type centrifugal pneumatic classifier having cyclone; blowers and pipelines. Hopper is communicated with loading branch pipe of ball mill whose discharge branch pipe is communicated with branch pipe for supplying disintegrated material to gravitation type centrifugal pneumatic classifier. Branch pipe for discharging large-size fraction from said pneumatic classifier is communicated with loading branch pipe of ball mill. Branch pipe for removing dust-laden air from gravitation type centrifugal pneumatic classifier is communicated with cavity of cyclone. Ventilated vibration mill of installation is provided with baffle type vortex pneumatic classifier having cyclone whose cavity is communicated with branch pipe for removing dust-laden air out of baffle type vortex pneumatic classifier. Each cyclone is communicated with magnetic separator. Between magnetic separator and cyclone of gravitation -type centrifugal pneumatic classifier sieve-type classifier is mounted. Loading branch pipe of vibration mill is communicated with branch pipe for discharging small-size fraction from gravitation type centrifugal pneumatic classifier, with over-sieve space of sieve type classifier and with branch pipe for discharging large-size fraction from baffle-type vortex pneumatic classifier. Discharge branch pipe of vibration mill is communicated with branch pipe for supplying disintegrated material to baffle type vortex pneumatic classifier.

EFFECT: possibility for producing large range of fractions of ready material, reduced energy consumption, enhanced efficiency.

1 dwg

Description

The invention relates to the field of mechanical processing of materials of increased hardness, for example, such as metallic chromium, by crushing, grinding and further sorting of the crushed material into fractions.

The invention can be used in the mining, metallurgical, chemical and construction industries.

The level of grinding materials and their fractional characteristics after sorting often determine the properties and value of finished products from recycled materials by increasing the reactivity of raw materials, the rate of subsequent technological processes, and increasing the productivity of technological equipment.

In this regard, modern industrial technologies require the creation of high-performance, cost-effective, reliable and durable grinding and sorting units capable of working in stressful conditions. This is especially important in the mechanical processing of materials of increased hardness (9 units on the Mohs scale), for example, metallic chromium, which is currently very widely used as an alloying component in the production of heat-resistant alloys, complex alloyed steels, cast irons, welding electrodes, surfacing wire, manufacture of powder metallurgy products. The listed materials and products are necessary in the most critical sectors of the national economy - energy, aircraft manufacturing, mechanical engineering, nuclear energy and space technology.

Increased requirements for the quality of finished products and products determine the production of increasingly finely divided materials with a wide range of fractions while achieving uniformity of particles in each fraction.

All these requirements make it necessary to further refine grinding and screening devices.

When the inventors of the present application carried out patent research to identify analogues of the invention from the world level of technology according to IPC classes В 02 С 23/00, В 02 С 23 / 08-23 / 16, solutions were found that are characterized by sets of features, partially similar to the set of significant features of the claimed invention.

The following technical solutions were selected and analyzed as analogues:

"Installation for the production of crushed stone and sand", ed. testimonial. USSR No. 1726033, 08.08.89.

"Installation of grinding and fractionation of powders of bulk materials of increased hardness." D.D. Vargasov, B.M. Prokhorov, V.M. Shevchenko. Proceedings of the SverdNIIkhimmash. Series: Equipment for equipping radiochemical processes. Issue 1 (65). Yekaterinburg, 1994. UDC 621.762.002.5.

"Shredded materials with particles of a certain size." UK application No. 1267655, CL B 02 C 17/00, B 02 C 17/20, 04/05/1968, publ. 03/22/1972

"The method of grinding material, such as cement clinker", the application of Germany No. 3815217, class. B 02 C 23/00, 23/38, 19/12, 04.05.88, publ. 16.11.89, No. 46.

"Method and installation for grinding material, mainly cement clinker", German patent No. 4224704, cl. B 02 C 23/12, B 07 B 9/02, 07/25/92, publ. 27.01.94.

"Method and device for grinding piece material", EPO application No. 0426651, 10.30.89, publ. 08.05.91, No. 19.

The known device, selected as an analogue, according to the application EPO No. 0426651 contains a ventilated horizontal impact-reflective crusher at the stage of preliminary grinding, equipped with a pneumatic separator or screen, a ventilated tubular ball mill at the stage of additional grinding. The discharge pipe of the shock-reflective mill is in communication with the pipe for introducing crushed air separator material or with an oversize screen space. The outlet pipe of the coarse-grained fraction of the pneumatic separator or the oversize screen space is communicated with the loading nozzle of the tubular ball mill, and the outlet pipe of the output of the fine-grained fraction of the pneumatic separator or oversize screen space is communicated with the loading nozzle of the shock-reflective mill.

The device is equipped with cyclones for cleaning the dusty air mixture discharged from the pneumatic separator or screen, fans and pipelines.

The advantage of this device is that both mills operate in ventilation mode and in a closed cycle with a pneumatic separator. The use of a shock-reflective mill in the first grinding stage in the known device for grinding "initial products for the production of cement" is justified, since these products are brittle material. It is known that “shock mills were most widely used for grinding soft and medium hard rocks” (see E.A. Dolganov. “Grinding of materials in the silicate industry.” Edition of S.I. Kirov UPI, Sverdlovsk, 1981 ., p.14, UDC 621.926: 622.73).

However, this circumstance makes it impossible to use the device according to EPO application No. 0426651 for grinding materials of increased hardness, for example, metallic chromium, whose hardness is almost 3 times higher than the hardness of cement materials (see I.R. Kleis, XXUueys. Wear resistance of elements of impact grinders actions, Publishing House "Mechanical Engineering", Moscow, 1986, p.5).

Closest to the claimed one is the solution described in the article by D. D. Vargasov, B. M. Prokhorov, V. M. Shevchenko "Installation of grinding and fractionation of powders of bulk materials of increased hardness". Proceedings of the SverdNIIkhimmash. Series: Equipment for equipping radiochemical processes. Issue 1 (65). Yekaterinburg, 1994, p.9-14, adopted as a prototype. The installation comprises a feed hopper, a ventilated ball mill equipped with a gravity-centrifugal separator equipped with a cyclone, fans and pipelines, while the feed hopper is in communication with a loading nozzle of a ball mill, the discharge nozzle of which is connected to the input pipe of the crushed material of the gravity-centrifugal separator, moreover its outlet pipe for coarse fraction is in communication with the loading nozzle of the ball mill, and the outlet pipe of the dust-air mixture gravity-price the tube separator is in communication with the cyclone cavity. The installation is equipped with a bag filter for cleaning the air leaving the cyclone, while the cyclone and bag filter have, respectively, a transport container of the finished product and a container of dust fraction.

The advantage of this installation is that when it receives 0.3 mm metal chromium powders, it provides selective grinding, reduction of dust formation, improving the quality of the obtained powders. All this is achieved thanks to the organization of the process associated with intensive ventilation of the working volume of the mill and a closed cycle of grinding and separation of the material.

However, the described installation is not able to effectively provide finer selective grinding (for example, to particles smaller than 0.1 mm) for the following reasons:

1. As is known (see E. A. Dolganov p.53), “with a decrease in the size of the crushed particles, their relative strength increases,” and therefore, in a low-energy-stressed ball mill, where the destruction of the material occurs only due to the mass of grinding balls, the efficiency decreases sharply chopping.

2. It is also known that with a decrease in the size of the crushed particles in grinding plants operating in a closed cycle with classifiers (see the Guide to ore dressing. TI Preparatory processes. M., "Nedra", 1974, p. 374), there is an increase in circulating load. At the same time (see EA Dolganov p. 46) “the greatest increase in mill productivity is observed at small values of the circulating load”.

The inability of the described installation to effectively provide finer selective grinding is also confirmed by the fact that this installation has only one grinding stage, while in the art there is a prevailing tendency for multi-stage grinding and sorting of materials, ensuring a wide range of fractions as a finished product. In addition, it should be noted that there is such a drawback as contamination of the finished product with metal particles (the so-called “hardware iron”), from which the equipment of the installation is made, due to significant wear of the working surfaces with increased circulating load (ballast), especially when processing materials with increased hardness like metallic chrome. This circumstance reduces the quality of the resulting product.

These shortcomings are deprived of the claimed installation for grinding and sorting materials of increased hardness, during operation of which the desired result will be achieved - obtaining a wide range of fractions as a finished product while reducing energy costs and increasing plant productivity, as well as reducing the contamination of the finished product with “hardware iron”.

The invention according to the present application, as well as the prototype, contains a feed hopper, a ventilated ball mill, equipped with a centrifugal air-passage pneumatic classifier equipped with a cyclone, fans and pipelines, while the feed hopper is in communication with a loading pipe of a ball mill, the discharge pipe of which is connected to the pipe the input of the crushed material of a centrifugal air-passage pneumatic classifier, and its branch pipe output large fractions communicated with the boot nozzle ball howl mill, and a dusty mixture discharge pipe of the centrifugal air-flow communication with the cavity pnevmoklassifikatora cyclone.

The inventive installation differs from the prototype in that it is equipped with a ventilated vibratory mill equipped with a chimney-vortex pneumatic classifier, equipped with a cyclone, the cavity of which is in communication with a branch pipe of the dust-air mixture of the chimney-vortex pneumatic classifier, each of the cyclones is connected by a crushed material with a magnetic separator, and between a magnetic classifier is installed by a magnetic separator of a centrifugal air-passage pneumatic classifier, the vibrating mill loading port is in communication with a branch pipe for removal of a small fraction of a centrifugal air-passage pneumatic classifier and with a sieve space of a sieve classifier, and the discharge pipe of a vibratory mill is in communication with a pipe for introducing crushed material of a swirl-vortex pneumatic classifier.

The invention meets all the criteria of patentability.

It is new, because the prior art does not know the solution with the same sets of essential features, as evidenced by the analysis of analogues of the invention given herein earlier in the present description.

The invention is industrially applicable, as it can be used in industry in those industries that are indicated at the beginning of the description. All the essential features included in the totality are feasible and reproducible and are used in full to achieve the expected technical result.

The invention meets the criterion of "Inventive step". When conducting patent research, the applicant has not identified solutions from the prior art that have features similar to the distinguishing features of the described invention.

The following description of the specific implementation of the installation and the implementation in it of the process of grinding and sorting of material is confirmation of this.

The drawing shows the inventive installation in General.

The installation contains a hopper 1 of the source material, a ball mill 2, equipped with a gravity-centrifugal pneumatic classifier 3, equipped with a cyclone 4, while the hopper 1 is connected by a pipe 5 with a loading pipe 6 of a ball mill 2, the discharge pipe 7 of which is connected by a pipe 8 with a pipe 9 of the input crushed into ball mill 2 material gravity-centrifugal pneumatic classifier 3, and its nozzle 10 output large fractions communicated with the loading nozzle 6 of the ball mill 2, the pipe 11, and the pipe 12 from ode dusty mixture gravitational centrifugal pnevmoklassifikatora 3 communicates with the cavity 4 of the cyclone conduit 13.

The installation is equipped with a ventilated high-energy-tensioned vibration mill 14, equipped with a swirl-vortex pneumatic classifier 15, equipped with a cyclone 16, the cavity of which is connected by a pipe 17 with a pipe 18 for extracting the dust-air mixture of the swirl-vortex pneumatic classifier 15. Each cyclone 4 and 16 is connected by a crushed material 19 and a magnetic separator respectively 20, and between the cyclone 4 and the magnetic separator 19, which according to technology and layout relate to gravity-centrifugal pneumatic classifier 3, is installed classifier 21. The loading pipe 22 of the vibration mill 14 is connected by a pipe 23 with a pipe 24 for the removal of a fine fraction of the gravity-centrifugal pneumatic classifier 3, pipelines 25 and 23 with a sieve space of the screen classifier 21 and a pipe 26 with a pipe 27 with a pipe for the removal of a large fraction of a flue-vortex pneumatic class 15, the discharge pipe 28 of the vibrating mill 14 is connected by a pipe 29 with a pipe 30 for introducing the crushed material of the jack-vortex pneumatic classifier 15.

The installation is equipped with the fans 31 and 32 necessary for its operation. The fan 31 is placed in a closed grinding system "ball mill 2 - pneumatic classifier Z", and the fan 32 - in a closed grinding system "vibration mill 14 - pneumatic classifier 15". Both systems incorporate bag filters 35 and 36 equipped with fans 33 and 34 to clean the dust removed from the systems from dusty particles of metallic chromium.

To collect the finished and pulverized product, as well as "hardware iron" in the installation, containers are provided in appropriate places. Containers 37 and 38 are installed under the magnetic separator 19, container 39 is located under the bag filter 35, containers 40 and 41 are located under the magnetic separator 20, and container 42 is located under the bag filter 36.

It should be clarified that the use of the gravitational-centrifugal pneumatic classifier in the claimed installation is due to the widest application of this type of pneumatic classifier in grinding systems of closed type with ventilated drum mills (see MD Barsky. "Fractionation of powders." Publishing House "Nedra", Moscow, 1980, Moscow , p.21, fig. 14; V.E. Mizonov, S. G. Ushakov. “Aerodynamic classification of powders.” Chemistry Publishing House, Moscow, 1989, p. 53, fig. 2.1). The specific design of the flue-vortex pneumatic classifier, which is equipped with a vibratory mill, is available in the book. V.E. Mizonova and S. G. Ushakova "Aerodynamic classification of powders". Publishing house "Chemistry", Moscow, 1989, p.57, Fig. 2.7. However, the performance of these pneumatic classifiers is not the subject of the present invention.

Installation works as follows.

From the hopper 1, metallic chrome is loaded uniformly in a predetermined quantity through the nozzle 5 into a ventilated ball mill 2.

The crushed chrome is carried out by the air flow from the grinding zone of the ball mill 2 and through the pipe 7 enters the pipe 8, from where it is introduced into the gravity-centrifugal pneumatic classifier 3 through the pipe 9.

In the lower part of the pneumatic classifier 3, called the gravitational step, a large fraction is separated from the incoming crushed chromium - particles larger than 2 mm and less than 5 mm, which is discharged from the pneumatic classifier 4 through the pipe 10 and sent through pipe 11 to the pipe 6 for loading into a ball mill 2 for regrinding.

In the upper part of the pneumatic classifier 3, its most important centrifugal stage, where due to the swirling of the material with gas by the existing blades, a fine fraction of chromium - particles smaller than 2 mm and more than 0.3 mm - is deposited on the wall of the pneumatic classifier 3 and then, rolling down it, is displayed from the pneumatic classifier 3 through the pipe 24 to the pipe 23, through which the fine fraction is transported to the load through the pipe 22 in the vibrating mill 14.

The dust-gas mixture with the size of the chromium particles contained in it is less than 0.3 mm, which is a product ready for industrial use (product No. 1), is discharged through the pipe 12 and sent through the pipe 13 to the cyclone 4. It separates the particles from the air, which is sent in a bag filter 35 for cleaning from dusty particles of chromium collected in a container 39 for transportation to re-melting, or to a warehouse of a product ready for industrial use as an additive in the manufacture of dyes. The resulting finished product from cyclone 4 enters the sieve classifier 21, where it is sifted through the “control” sieve, and larger particles randomly captured by the air flow remain above the sieve. They are discharged through a pipe 25 from the sieve space of the sieve classifier 21 to the pipe 23 and then enter the pipe 22 for loading into the vibrating mill 14. The sifted finished product from the sieve classifier 21 is fed to a magnetic separator 19, in which the "hardware iron" is separated from chromium particles after which the finished product is sent to the container 37, and the "hardware iron" - to the container 38.

The small fraction of metallic chromium loaded into the ventilated vibratory mill from the pneumatic classifier 3 is processed in the vibration mill 14 using "special processing bodies (balls, cylinders, rods, rolls, pipes, etc.)" (see "Modern vibration mills and their application in non-ferrous metallurgy abroad. Overview information. Issue 3. Moscow, 1987, p.2).

In the described specific example of the operation of the inventive installation, balls that were grinding media in the ball mill 2 of the installation can be used as these special processing bodies. Their size as a result of abrasion during grinding of metallic chromium decreases to a size of 10-15 mm (with an initial ball size of 45-60 mm). Balls of this size are ineffective for grinding in the ball mill 2 of the original chromium, where particles up to 20 mm in size are supplied, but are suitable for producing thin and ultrafine chromium fractions in the vibrating mill 14, where particles whose particle size does not exceed 2.0 mm arrive. As a result of the combined action of the balls and the vibrating chamber of the mill 14, the chrome is crushed. The crushed metal chrome is transported through the discharge pipe 28 of the vibration mill 14 through a pipe 29 and introduced into the flue-vortex pneumatic classifier 15 through the pipe 30. The inner cone with fender blades (not shown), which is present in the upper part of the pneumatic classifier case 15, is called a rotating one, and forms a rotating from an external electric cart. In the vortex zone, the metal chromium that is crushed in the vibratory mill 14 is sorted. Its particles up to 0.1 mm in size, having low inertia and, together with the air flow, pass into the gaps between

rotating blades and not experienced collisions with them, are considered small and are the finished product No. 2, obtained on the inventive installation.

A large fraction with a particle size of more than 0.1 mm, but less than 2.0 mm, having undergone a collision with the jack blades, is discarded to the wall of the housing of the pneumatic classifier 15 and, dropping down the gap between the inner cone and the housing, enters the pipe 27 and then through the pipeline 26 is transported through pipe 22 to a ventilated vibratory mill 14 for regrinding, and from there to re-sorting into a pneumatic classifier 15.

The fine fraction is removed from the pneumatic classifier 15 through the pipe 18 and through the pipe 17 is sent to the cyclone 16, where the chromium particles are separated from the air, which is then sent to the bag filter 36 to clean the air from dusty particles of metallic chromium collected in the container 42 for transportation or warehouse for industrial use as an additive in the manufacture of dyes, or for remelting.

The finished product No. 2 obtained in cyclone 16 enters a magnetic separator 20, in which the metal chromium formed during grinding in the vibration mill 14 of the “hardware iron” is separated from the particles of metallic chromium, after which the finished product is sent to the container 40, and the “hardware iron” into container 41.

As follows from the above description, the inventive installation, which is a successful combination of necessary and sufficient to achieve high results technological units and equipment, allows to obtain a finely divided product with the release of several fractions of crushed metal chromium, which leads to the expansion of its scope in finished products and products with achieving their high quality.

Claims (1)

An installation for grinding and sorting materials of increased hardness, for example, metallic chromium, containing a feed hopper, a ventilated ball mill, equipped with a gravity-centrifugal pneumatic classifier equipped with a cyclone, fans and pipelines, while the feed hopper is in communication with a ball mill loading port, the discharge port of which is connected with the input pipe of the crushed material of the gravity-centrifugal pneumatic classifier, and its large output pipe the rods are connected with the loading nozzle of the ball mill, and the nozzle of the dust-air mixture outlet of the gravity-centrifugal pneumatic classifier is communicated with the cyclone cavity, characterized in that the installation is equipped with a ventilated vibratory mill equipped with a rotational-vortex pneumatic classifier equipped with a cyclone, the cavity of which is connected to the dust mixture from the nozzle vortex pneumatic classifier, each of the cyclones is connected by a crushed material with a magnetic separator, and between the magnetic separator a sieve classifier is installed and a gravity-centrifugal pneumatic classifier cyclone, the vibratory mill loading port is in communication with a fine fraction outlet pipe, a gravity-centrifugal pneumatic classifier overflow space and with a large fraction discharge branch pipe, a swirl-vortex discharge pipe of a large class of material pneumatic classifier.