SU1761704A1 - Method for granulating slag melt - Google Patents

Abstract

SUMMARY OF THE INVENTION: A free-falling jet of molten slag is crushed by a jet of water supplied to meet the jet at a speed that balances the zone of melt crushing between the outflow of the melt and steam, determined by the dependence given in the description text. As a result, 90-95% of the granules have the correct spherical shape. 1 tab.

Description

The invention relates to the field of metallurgy and can be used in the processing of liquid metallurgical slags for the production of building materials for various purposes.

There is a method of granulation of metallurgical slags, including hydrocellulose two-stage granulation of a melt with the supply of water to the first stage at a speed of 20 ... 25 m / s in an amount of 0.3 ... 0.5 m / t of melt, and the second - steam-air mixture heated to 350 ... 450 ° C in the amount of 40 ... 80 m / t of melt at a ratio of steam and air (1 ... 5): 20, with the steam-air jet being supplied parallel to the axis of the trough.

However, the method does not ensure the constancy of the particle size distribution and stability of the physicomechanical characteristics of the granules.

A known method of priming granulation of metallurgical slags by crushing due to primary cooling of the melt with a stream of gas or steam, into which water is introduced in an amount of 0.1 ... 10 kg / m, and final cooling with water, the primary cooling of the slag being carried out to 800 ... 1250 ° C. The method chosen by the authors for the prototype.

The disadvantage of the method is that the granules during the flight have an acceleration different from the acceleration of the free fall. In addition, upon impacting the water surface, the granules have a temperature of 800 ... 1200 ° C. This leads to an increase in the deformability of the granules and an increase in the consumption of intensely evaporated water.

The purpose of the invention is to improve the quality of the granulation due to the production of spherical granules of uniform size.

This is achieved by the fact that in the method of granulation of a slag melt by crushing the melt with a jet of water vapor and subsequent cooling with water, a jet of water vapor is fed against the free falling jet of the slag melt at a rate determined by the dependence

SL

WITH

S

about l

0

RP

to with

h S0 mn RQ T 2 un / On Vn

where Vn is the flow rate of a jet of water vapor, m / s;

K - coefficient taking into account the dynamic viscosity of the melt and streamlined edges of the nozzle opening, K (0.026 ... 0.027) x 107;

PP is the density of the melt, kg / m3;

rp is the steam density, kg / m3;

q — acceleration of free fall, m / s2;

h is the distance from the nozzle hole of the melt flow to its crushing zone, m;

So is the hole area of the melt outflow nozzle, m;

GPP - mass of steam, kg;

fin is the molecular weight of the vapor;

R0-universal gas constant, kg-m / deg, kg-mol;

T - steam temperature, K;

Vn - the volume of steam supplied, m

The interval of water vapor supply rates, limited by analytical dependence, provides a suspended state of the slag molten jet with a jet of water vapor supplied to meet the localization of the melt crushing zone, with the result that the granules obtained in the crushing zone have a motion path (steeply dipping parabola) the acceleration of free fall, contributing to the preservation of the correct spherical shape of the granules. At the same time, the intensification of the cooling rate of the granules and the regulation of the distance from the crushing zone to the water surface ensures the temperature of the granules at 400 ° C by the moment of contact, when the plasticity of the granules impacted with the water surface is 3 ... 5 times lower, which reduces the degree of deformation of the granules and deviation from the correct geometry.

By regulating the rate of water vapor supply and the distance from the zone of crushing the melt jet to the water surface, slag of different size and composition are obtained from metallurgical slags of different composition and properties.

Example 1. A molten slag of steel 25L in the amount of 0.5 tons at 1470 ± 15 ° С is fed along a chute to a ladle, the outlet of which has a diameter of 100 ± 2 mm. A disperser nozzle mounted above the nozzle of the bucket is placed above the mirror of the water basin with the possibility of axial movement in the vertical plane. A stream of water vapor is fed through the nozzle at a speed of 440 m / s

375 ± 5 ° С. The distance between the bucket nozzles (melt supply) and dispersant (steam supply) is set at 2000 mm.

Stabilizing steam with

electromagnetic flaps, open the melt supply nozzle from the ladle, and the free falling melt jet is balanced with a steam jet with the localization of the melt crushing zone at a distance of 1600 mm from

melt feed nozzles. The granules formed in the crushing zone realize in the trajectory of their movement a free fall acceleration section, where, under the action of surface tension forces, a regular spherical shape is formed, v is cured with continuous cooling to a temperature in the order of 400 ° C, when their plasticity is insignificant and their strength ensures deformation-free impact with the water surface of the granule collection basin The number of substandard granules regulated by the violation of the stability of the process in completing th expiration of the phase

jet melt does not exceed 4.,. 5% of the total volume of dispersed granules.

The results of the granulation are given in the E table.

Example 2. The molten slag steel 35 /

in an amount of 0.4 t at 1500 ± 15 ° C, granulation is carried out in a sequence similar to that shown in Example 1. The distance between the steam supply and melting nozzles is 2000 mm, the distance from

the crushing zone to the nozzle of the discharge of the melt of 1680 mm, and to the water surface of the basin - a collection of granules - 2080 mm. The amount of substandard granules of the total dispersed volume was 3.9%.

The speed of the steam jet in Example 2 is 459 ms.

The results of the granulation are given in the E table.

Analysis of the results given in tab.

face, testifies to the achievement, when using the proposed method, of a stable homogeneous composition of a granule / size 2.5 ... 5.0 mm (80, 87% of the total volume of dispersed granules) containing

By pressing granules of the correct spherical shape, not less than 90 ... 95% of the total volume of dispersed granules.

Claims (1)

Claims The method of granulation of a slag melt by crushing a melt with a stream of water and steam and then cooling it with water is characterized in that, with the aim of improving quality by obtaining one spherical granules of native size, a jet of water vapor is fed towards a freely falling jet of molten slag at a rate determined by the dependence & L RP d h So mn Ro T 2 {in / on Vn where Vn is the flow rate of a jet of water vapor, m / s; / Ep - steam density, kg / m; K - coefficient taking into account the dynamic viscosity of the melt and 0 streamline edges of the nozzle opening, K (0.026 ... 0.027) x 107; Pp is the melt density, g is the acceleration of free fall; h is the distance from the nozzle hole of the melt flow to its crushing zone, m; So is the hole area of the melt outflow nozzle, m; tp is the mass of steam, kg; fin is the molecular weight of the pair; Ro-universal gas constant, kg-m / hail, kg-mol; T - steam temperature, K; Vn is the volume of steam supplied, m3. The results of testing the proposed method of granulation of slag melt in laboratory conditions and in the conditions of the steel mill e-da Chirchikselmash