RU2080931C1 - Method for grinding two and more raw materials - Google Patents

Abstract

FIELD: grinding equipment for construction materials, and for chemical, metallurgical, ore concentration and other industries. SUBSTANCE: according to method, grinding and drying of two and more materials with different grindability are performed simultaneously. Hard-to-grind brittle material (limestone) is subjected to grinding in press-roll disintegrator together with nonbrittle dampened material (clay) in mill. Agglomerate of brittle material and primary nonbrittle dampened material are subjected to combined grinding and drying in hammer-type mill-drier and to final drying in air-type separator. Coarse particles of ground material carried away from hammer-type mill-drier by drying agent and separated in air-through classifier of primary cleaning and middlings isolated in separator are delivered to roll-type machine for final grinding together with primary material. Hammer-type mill-drier is fed with clay component of raw burden with moisture content of up to 25%. EFFECT: high efficiency. 3 cl, 1 dwg

Description

 The invention relates to techniques for grinding raw materials and can be used in the construction materials industry, in the chemical, metallurgical, enrichment and other industries.

A known method and installation for the joint grinding of two or more brittle materials having different grindability using the high-pressure roll process or press grinder at the first stage of grinding, moreover, brittle brittle material, for example blast furnace slag, before grinding together with easily brittle brittle material, for example portland cement clinker, crushed in the gap of the roll machine to the state of individual grains or agglomerate [1]
A device is also known for crushing and grinding a brittle, in particular wet, material consisting of a hammer mill dryer, an air passage separator and a roller press [2] In this installation, all the original brittle material is first subjected to grinding and drying in a hammer mill dryer and then separation in an air-passage type separator, the finished product from which is separated in a dust precipitation filter, and the grits are fed for regrinding into a roller press, at the exit of which the compressed is grinded th grit in the form of agglomerate fed hammer mill-dryer.

 A known method and installation for crushing or grinding wet materials and drying them in a stream of hot gas (application Germany 3901436, CL B 02 C 4/02), in which wet materials are subjected to grinding in a high-pressure roller process to form an agglomerate, and wet agglomerates subjected to separation and drying in a separator using a stream of hot exhaust gases.

 The literature contains technological schemes (system) for grinding raw materials, including press roll grinders, hammer mills, dryers and air separators, where in technological schemes (systems) the initial wet raw material is first fed to a roller press (press roll grinder), leaving the agglomerate from which is subjected to grinding and drying in a hammer mill dryer and partially in an air separator. The finished product from the separator is discharged into dust precipitation filters, and the grits are sent for regrinding in a roller press.

 In the system, all of the original raw material is initially fed to a hammer mill dryer, from which the pre-shredded and dried material is transferred to the air-passage separator by a stream of hot gases. The finished product from the separator is discharged into a dust settling device, and the grits are sent for regrinding into a roller press, in which only one grinder is subjected to grinding.

 The technological schemes of grinding and drying of raw materials containing roll presses (press roll grinders), hammer mills, dryers and air-passage separators are the most suitable for cement production, but each of them has little versatility for the grinding and drying press of multicomponent raw materials , since in them the same processing goes through all the raw material.

Stoffe" (способ и установка для совместного измельчения двух или более хрупких материалов с различной размолоспособностью).As a prototype of the selected method described in the application of Germany N 3314103, class. B 02 C 19/00, 04/19/93 "Verfahren und Anlage zuz gemeinsamen Mahlung zweier oder mehzezes unterschiddich mahebazez

Stoffe "(method and installation for joint grinding of two or more brittle materials with different grinding properties).

 Significant disadvantages of this method is its use only in brittle materials, for example, such as blast furnace slag and Portland cement clinker, and its inapplicability to grinding a raw material charge containing non-brittle wet raw materials.

 The aim of the invention is to increase the grinding efficiency of two and multicomponent raw materials and reduce specific energy consumption; improving the drying efficiency of wet raw materials with a decrease in the specific consumption of thermal energy; reduction of capital investments and operating costs during the creation and operation of drying and grinding plants.

This goal is achieved by the fact that in the development of the known method in relation to a raw material mixture containing non-fragile wet material, the agglomerate of brittle (semi-brittle) material formed in a press roll grinder and the initial easily grinding non-fragile wet material are subjected to joint grinding and drying in a hammer mill-dryer the material is produced by drying gases in an air separator; the raw material, crushed and dried in a ventilated hammer mill dryer, is subjected to a two-stage air classification with separation from the gas-material stream at the outlet of the hammer mill dryer, first of the coarsest material fractions and then in the air separator of the remaining unmilled particles (grains), moreover, separated from the gas stream, coarse fractions and grains are partially or completely crushed in a press roll grinder together with the initial brittle (semi-brittle) material; the clay component of the raw material charge with a moisture content of up to 25% is fed into the hammer mill dryer
The proposed method is illustrated in the drawing.

 Comparison of the claimed technical solution with the prototype of the method made it possible to establish compliance with its criterion of "Novelty."

 When studying other known technical solutions in the art, the same features that distinguish the invention from the prototype were not identified, and therefore, the claimed technical solution meets the criterion of "Significant differences".

The essence of the claimed method is represented by the technological scheme of the installation, according to which the initial brittle (semi-brittle) material Mxd and the brittle (semi-brittle) additives Mxd included in the raw material charge from the feed hoppers 1 and 2 are fed through continuous weighing batchers 3 to the conveyor belt 4 and from it to the hopper constant level (strain gauge hopper) 5, which provides uniform specified power to the crushed material of the press roll grinder 6. Obtained in the press roll grinder 6 by pressing under OKIMO pressure brittle (poluhrupkogo) sinter the material by the conveyor 7 is moved to the loading device 8, the sealing of the hammer mill-dryer 9, wherein the layer on the sinter, the movable conveyor 7, is fed continuously source legkorazmalyvaemy wet brittle material, such as clay rock Mnv. Simultaneously with the continuous flow of the raw material charge M _{W $} (Mx + Mxd + Mnv), hot drying gases Gg are supplied to the mill-dryer 9 through a parallel channel. The material crushed and dried in a hammer mill dryer is fed under vacuum first to an air-pass classifier 10, by means of which coarse fractions of material Gf are separated from the gas stream. The removal of coarse fractions of the Gf material from the gas stream allows one to reduce the energy consumption for lifting with the feeding of the crushed material into the separator and to reduce the wear of the separator parts. The coarse fractions of the material GF by means of a vertical bucket elevator 11 and a conveyor 12 are fed into a strain gauge hopper 5.

 The gas-material stream purified from coarse fractions under vacuum is fed to a dynamic air-passage separator 13, which has a rotating separating rotor connected to a drive with a smoothly varying speed, and works according to the counter-current separation principle. At the outlet of the separator 13, the finished product is separated from the gas mixture in the group of dust precipitation cyclones 14. The gases purified in the group of cyclones 14 from the bulk of the material are fed through the mill fan 15 for final cleaning to the dust filter 16, from which dust-free gases are discharged through the end fan 17 into atmosphere, and the material caught in the form of fine dust is attached to the finished product.

 In the area of the dust and gas path from the hammer mill-dryer 9 to the separator 13 inclusive, the particles of crushed material are subjected to final drying. Grain Kp, separated in the dynamic separator 13, is fed into a strain gauge hopper 5. The initial raw material charge Ms, coarse fractions Gf and grains from the separator Kp are jointly fed to a press roller grinder 6.

 If necessary, coarse fractions of the material Gf can be partially fed to the grinding mill-dryer 9 through grinding device 8 (feeding device not shown in the drawing), and dust-free gases from the pressure line of the mill fan 15 can be partially recycled to the dust-gas stream before the entrance to the separator in the vertical duct (not shown). The availability of devices for regulating the indicated flows of material and gases allows, while controlling the speed of the separating rotor of the separator 13 and the operating mode of the mill fan 15 at a given power supply of the grinding plant with the source material, to ensure the optimal operating mode.

 When the humidity of the feedstock mixture is up to 7%, hot gases are used, coming from baking heat exchangers of dry kilns of the cement clinker production method. It is possible to grind the clay component of the raw material charge with higher humidity (up to 25%) provided that hotter drying gases are supplied from the freestanding furnace to the hammer mill dryer (not shown).

 The proposed method of grinding raw materials has been successfully tested on a laboratory bench installation of VNIItsemmash JSC, consisting of a press roller mill, a hammer mill dryer and a dynamic air-passage separator.

Claims (4)

 1. The method of grinding two or more raw materials, characterized by different ability to grind, in which hard-to-brittle brittle material is pressed in the gap of the roller machine to the state of sinter and (or) individual grains before grinding in a mill together with easily-grinding brittle material, characterized in that , in order to increase the grinding efficiency and reduce the specific energy consumption, agglomerate and individual grains of solid brittle wet material, such as limestone, suspension gayut comminution and drying in a mill together with a wet brittle material, such as clay.  2. The method according to claim 1, characterized in that the agglomerate of brittle material and the original non-brittle wet material is subjected to joint grinding and drying in a hammer mill dryer and drying in an air separator.  3. The method according to PP.1 and 2, characterized in that the coarse particles carried out from the hammer mill dryer with a drying agent, the crushed material separated in the air-pass coarse classifier, and the grains separated in the separator, are fed to the grinding machine, attaching to the original brittle material.  4. The method according to claims 1 to 3, characterized in that the clay component of the raw material charge with a moisture content of up to 25% is fed into the hammer mill dryer