JPS627652A - Treatment for steel slag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing roadbed materials from steelmaking slag, and more particularly to a method for producing stable roadbed materials that do not expand or collapse in a short period of time.

Conventional technology Steelmaking slag generated in the steelmaking process has an angular shape, is hard, and has excellent properties as a roadbed material for asphalt roads, such as good engagement during road compaction (and has hydraulic properties). are doing.

After steelmaking slag is discharged from a converter or electric furnace, it is cooled at a treatment plant, excavated to remove ingots, and crushed to size using a crusher.

However, if used directly as a roadbed material, the slag expands and collapses due to rainwater, etc., so it cannot be used directly as a roadbed material.

In converters, quicklime is used as a dephosphorizing and desulfurizing agent for molten steel.
Cao) is added, and most of it is sludged.
Lz Si, -A silicate (2CaO@S iO*
, 3Ca0SiO*) and calcium ferrite (2CaO・FCaO5), but since the blowing time in the converter is short, about 20 minutes, it is not completely slaged and unslaged lime ( Cab), that is, free lime remains.

This free lime has a slower hydration reaction than regular quicklime (
, it does not react immediately when it comes into contact with water, but after some time, a reaction occurs as shown by the chemical formula: CaO+ )ho →Ca (OH) *This reaction causes volumetric expansion, causing the converter slag to expand and collapse. let Therefore, in the past, slag that had been cooled, crushed, and had its particle size adjusted was piled up in the open, ie, aged, and the free lime in the slag was reacted with rain water or sprinkled with water to stabilize the slag before use. However, there are problems in that it takes a long period of six months or more for the reaction to be completed and stabilized, requires work such as loft management, and also requires a large aging field.

The present invention has been made in view of the above circumstances, and its purpose is to complete the reaction of free lime in a very short period of time, and to achieve a! ! An object of the present invention is to provide a slag treatment method that allows steel slag to be used as a roadbed material.

Means for Solving the Problems The present invention involves cooling steelmaking slag and then crushing it to adjust the particle size.
This is a method for treating steelmaking slag, which is characterized by sprinkling water while heating to 80° C. or higher.

Function Since the present invention is a method for treating steelmaking slag configured as described above, when treating steelmaking slag, after crushing the steelmaking slag to prepare the particles, 1 ton of steelmaking slag is crushed per day while heating to 80° C. or higher. When the slag is sprinkled with 1501 water, the expansion index becomes 0.1 or less within 10 days as shown in FIG. 1, and the reaction of free lime is substantially completed. Note that, as shown in FIG. 1, since the reaction rate is proportional to the heating temperature, the reaction of free lime can be further accelerated by increasing the heating temperature. In addition, if water is not sprinkled, the reaction rate will be slow (the expansion index will be 0.1 in 10 days).
It cannot be less than that. Furthermore, as shown in Figure 2, when the amount of water sprinkled is increased, the reaction rate becomes faster.

EXAMPLE Hereinafter, an example of the method of the present invention will be explained based on the accompanying drawings.

The steelmaking slag used in the method of the present invention has a grain size of 401 square meters or less. The reason for this is that JISA-5015 stipulates that road slag should have a particle size of 40□ or less.

After the slag treatment, the particles become slightly finer overall due to disintegration, but as shown in FIG. 3, there is no major change.

Converter steelmaking slag whose crushing particle size has been adjusted to 40 Tsuru or less is
It is inserted into a device as shown in FIG. 4, and heated and watered. In the figure, (1) is a heating device, an electric heater (2) is built into the heating device (1), and above the heating device (1) is a container (4) into which the steelmaking slag (3) is inserted. is provided. There is a temperature control panel on the upper side wall of the container (4).
A temperature controller (not shown) controls the temperature inside the container (4) to be 80° C. or higher.

Furthermore, a water sprinkling nozzle (6) for sprinkling water is provided above the temperature control panel.

1 day+ for 1 ton of steelmaking slag using the above equipment
When water was sprinkled at a rate of 50 Il, the free lime reaction could be accelerated to such an extent that the slag expansion ffi index could be kept below 01 within 10 days.

In the detailed description of the present invention, converter slag is used as the steelmaking slag, but electric furnace slag may also be used.Also, an electric heater is used as the heating means, but it can be , sensible heat of exhaust gas from a soaking furnace or the like may be used.

Effects of the Invention As is clear from the above explanation, the method for treating steelmaking slag of the present invention allows steelmaking slag whose grain size has been adjusted to be heated at 80°C.
Since water is sprinkled while heating the slag to a higher temperature, the reaction of free lime in the slag is completed in a short period of time, and the steelmaking slag can be turned into a stable roadbed material that does not expand and collapse in a short period of time. It has excellent effects such as eliminating the need for management work and large aging areas.
,

[Brief explanation of the drawing]

Figure 1 shows the amount of water sprinkled on converter slag and the heating temperature:
Slag expansion index and elapsed days when changed
(Graph showing the relationship, Figure 2 is the slag expansion index
Graph showing the relationship between □ and the amount of water sprinkled during heating, Figure 3
1 is a graph showing the relationship between the size of the sieve openings of the sieve through which the slag passed before and after treatment and the percentage of amount passed through, and FIG. 4 is a front sectional view of the apparatus used to carry out the method of the present invention. be. 1... Heating device 2... Electric heater 3...
Steelmaking slag 4... Container 5... Temperature sensor
6... Watering/cheating Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A method for treating steel-making slag, which comprises cooling the steel-making slag, crushing it to adjust its particle size, and sprinkling it with water while heating it to 80°C or higher.