RU2004512C1 - Method for filler production - Google Patents

Abstract

Usage: when firing granules of aggregates in a rotary kiln. SUMMARY OF THE INVENTION: In a method for producing aggregate, raw granules and sand are fed into a rotary kiln at the same time with a ratio of (1.5-2.0) -1 by volume. The aggregate characteristic is apparent with a density of 026-029 g / cm, the coefficient of variation in apparent density is 5.8 - 6.7, and the coefficient of variation in compressive strength is 6.8 - 8.3. 2tab.

Description

The invention relates to the production of hundred-year-old materials and may be irrelevant. In the manufacture, fill- (, g for lightweight concrete, for example, 1 ohr, metal floor, shungizit gravel, etc.

There is a known method for manufacturing small beads: - during the firing of clay granules to the outside of the furnace with the simultaneous supply of a zone with a coal angle of 10-24% at mass. h the ratio of ash and granules 1: (2.5 4.9),

In the bottom method for manufacturing expanded clay, the ratio of ash to granules by volume is 1: (2.2-4.4), which means that approximately 85-90% of the granules are in the ash layer, the rest is in the atmosphere of smoke holes. Thus, a two-layer translational motion is created by the material not an eye. Moreover, the speed difference is significant, since the ash has small values of the surface forces of internal interaction, in particular, the angle of repose is 10-15 °. Oak leads to instability of the hydrodynamic movement of the bed (material pschhr) to the rotary kiln, resulting in a large flow, which substantially increased (w; .1br, erc of a significant difference in the density of granules and ash. It is necessary to note that this the difference is also non-uniform1, pure - it changes (200-250) to - (300-350) kg, in this case, the reverse flow is formed not only in the surface layer of the granules - flue gases, but also granules in the ash layer - granules As a result, the reverse flow causes heterogeneity of the quality indicators of expanded clay and their Reductions (at a bulk density and strength) due to the irregular movement of the pellets and non-uniform heat input thereto. ultimately degraded controllability firing process and reduced productivity of the furnace.

At a temperature of about 800 ° C in a material layer consisting of granules and ash with a content of 10-24% coal, the process of burning of the latter begins, which is uncontrolled in a rotary kiln, and leading not only to sintering of ash, but also to its sintering. which is unacceptable in the production of granular porous fillers. The process uncontrollability is enhanced by the fact that the ash content in the ash is inconsistent (10-24%). As a result, this leads to a deterioration in the expansion conditions, which will also negatively affect the quality of the finished product and furnace productivity .

HEC zones are highly dusty

m series When feeding ash together with gra, -miniunos ash is absent only before

the moment the ash is wet. But since it dries quickly and easily, at 100 ° C, i.e. almost at the very beginning of the furnace, a significant part of it will be taken into the dust cleaning system of the rotary kiln, which will require a significant increase in the throughput of the dust cleaning system and unjustified production costs. In existing plants and workshops, this circumstance leads to a significant deterioration of the ecological environment.

As a rule, ashes of thermal power stations in dumps contain up to 30% of slags in the form of small and large crushed stone. Grains of small and large gravel falling together with ash and granules into a rotary kiln at a temperature of about 850 ° C begin to soften, causing adhesion with ash particles and fired granules, stimulate sintering and weight expanded clay gravel and sand.

The closest technical solution to the proposed one is a method of producing lightweight aggregates by firing granular material in a rotary kiln with continuous action and feeding quartz sand with a particle size of 0.5-1 mm continuously in an amount of 0.20-0 to the zone of intense heating. 25 ma.ch. by weight of the granules.

This method involves the use of quartz sand in an amount of 0.20-0.25 wt.h. by weight of granules or 0.13-0.16 vol.h. from their volume. This leads to the fact that approximately one third of the volume of the material flow of granules is in a layer of quartz sand, and one third of it is in a usual, traditional environment of flue gases, creating a two-layer translational motion of the flow. Due to the fact that fine-grained materials have a lower speed of translational motion in the material flow, the velocity field of the granules changes significantly - the top layer has a high speed. In a sand layer, the speed of granules with sand is slower than in a conventional, conventional environment. The pouring of granules with sand cannot cover the entire volume of the layer, since there is not enough sand. A substantial part of the volume (approximately two-thirds) of the material stream is fired using a traditional, widely practiced firing scheme. Due to the violation of the velocity field of the granules in the furnace, an unstable hydrodynamic situation is created which leads to the formation of a reverse flow. As a result, the PTC implemented an uneven supply of getz to the gr-hg / ppm

SEARCHING IN THE LAYER OF PSOR AND h yy,; pniy l ho4

sand, which leads to a decrease in the properties and their heterogeneity in bulk density and strength of the finished product, and which, in turn, reduces the control of the firing process and the productivity of the furnace.

In addition, this method provides for the return of quartz sand to the process after completion of firing. However, in the process of firing the granules, a certain amount (depending on the properties of the raw material) of a fine fraction (0-5 mm) that remains in the quartz sand is always formed. When reusing quartz sand with fine expanded clay fractions having a much lower melting point than during the initial firing, the latter are melted and lead to the formation of cakes directly in quartz sand and then granules. Sintering enhances the instability of the hydrodynamic movement of the material flow in a rotary kiln, to a greater extent increasing the heterogeneity of the aggregates in bulk density and strength. Therefore, in order to reuse quartz sand, fine fractions of expanded clay should be separated from it, which is associated with additional costs that increase the cost of aggregates.

The purpose of the invention is to improve the quality and uniformity of aggregates in density and strength.

The goal is achieved. that raw granules and mineral sand are simultaneously fed into the rotary kiln at a ratio of (1.5-2): 1 both.

EXAMPLE-Volzhsky river quartz sand and quartz-feldspar sand of the Monchegorsk deposit are used as mineral sand, and clay of the Smyshlyevsky deposit and shungite-bearing rock of the Nigozersky deposit are used as raw material for the production of granular material.

The chemical composition of the starting materials is given in table 1.

Granules from clay of Smyshl evsky deposit are obtained by traditional plastic technology. The prepared granules or screenings from shungite-containing rock crushing are metered onto a conveyor belt feeding them to a rotary kiln. Sand is dispensed onto the same conveyor belt in the ratio sand: granules 1: (1.5-2). Heat treatment of the pellet with pitch is carried out at a temperature optimal for the expansion of the pellet. After firing and exiting the rotary kiln, the mixture of calcined sand and expanded granules (expanded clay, schungizite) is cooled in a 6-working refrigerator. The results of 5 tests of expanded clay and shungizite and burning sand are presented in table 2.

The simultaneous supply of sand and granules in a ratio of 1 .- (1.5-2) by volume ensures uniform movement of granules from the beginning 10 l to the end of the furnace, i.e. along its entire length at a speed equal to the speed of the sand.

The uniform movement of the material flow a completely eliminates the formation of a reverse flow 15 and allows us to provide the necessary and sufficient supply of heat to each granule of the material flow, which makes it possible to completely extract the raw material resources by swelling, i.e. reach the minimum possible bulk density of the porous aggregate of the published raw material and increase its strength. Uniform flow movement significantly improves process control, 5 ensures high reliability of automatic control systems.

When heated, chemically inert, non-swellable sands do not enter into chemical reactions, including the formation of a liquid phase, therefore there are no processes of speciation and, moreover, melting in the material flow, which ensures stability of the hydrodynamic regime in the furnace and increases unreliability the whole technological process.

The material flow from granules and sand has increased elasticity and viscosity, which provides better preservation of the gas products of chemical reactions in the 0 granules themselves, therefore a more complete swelling is achieved. The difference in the swelling of small and large granules is significantly reduced, their uniformity in density and strength increases. 5

An increase in the proportion of granules in the ratio of sand and granules in a mixture of more than 1: 2 leads to a two-layer movement of the material flow and to the formation of a reverse flow

0 granules, and a decrease in the proportion of granules in the ratio in the mixture of sand and granules less than 1: 1.5 leads to the loss of economic feasibility of using this method. According to the implementation of the method, the resulting calcined sand (quartz, feldspar, etc.) is an environmentally friendly fine aggregate of concrete, since in the process of passing through the kiln all harmful inclusions underwent fine decomposition.

() B} L is the nipple certificate of the USSR I 47777 cells C 04 V 14/12, 1986.

USSR author's certificate N 695986, cl. From 04 to 18/06. 1977.

Material

Clay mouse Chev- xio m ° C - deduced from Cr eu from crushing

I / R H)

; to r Ggglich Nitver

 ,. i h about LLLI G R- s- OH

"R (ir; y

iv j i oleVOShPgPO

at m Mot

Clay Smyshl evsko about the field Screenings from the crushing of schungite-bearing shales of the Nigozerskoye deposit Reina kpartsevy

sand

Quartz field - feldspar - VOSh sand of Monchegorsk deposit

Table 1

Continuation of table 1

 2004512t

Claims (1)

The claims are intended to improve the quality and uniformity of the aggregate in terms of density and durability. raw pellets and sand are fed into the CEL by burning raw granules into a rotary kiln, a single-rotary kiln is fed and min-5 is fed into it at a ratio of (1.5 - 2); 1 of natural sand, characterized in that. what, with volume.