JPS623051A - Manufacture of road bed material - 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 [Industrial Application Field] The present invention relates to a method of actively utilizing powdered converter slag and blast furnace wet dust as a roadbed material.

[Conventional technology]

Conventionally, one of the ways to use converter slag is to use it as a roadbed material for paved road construction.

When converter slag is applied to a roadbed material, the converter slag usually contains 3 to 7% free lime and is finely dispersed throughout, which leads to the collapse of the roadbed material. For this reason, before using it as a roadbed material, it is common practice to coarsely crush the consolidated slag, subject it to aging treatment by exposing it to the open air for six months or more, and then crush and size it before use.

In addition, during the production of crushed stone from converter slag, a large amount of powder with a particle size of 2 or 5 dragons or less, which is generated in large quantities (approximately 45%), is partially used for civil engineering and cement, but most of it is left unattended. The current situation is that

On the other hand, in order to utilize the high Fe content, blast furnace wet dust is reduced and roasted into pellets to remove ZnL.
, Attempts have been made to metallize Re and use it as part of the blast furnace charging raw material, but it is currently not put into practical use due to the high manufacturing cost.

In addition, as another treatment method for blast furnace wet dust, JP-A-59
As described in No. 13883, a method has been proposed in which heated limestone is used to raise the temperature and evaporate water to make use of it. In this case, especially about 1000 limestone
Since quicklime obtained by heat treatment at ℃ is mixed with a wet substance and dried by the heat of reaction, the cost is high.

[Problem that the invention seeks to solve]

The present invention eliminates the need for long-term fixation of converter slag when it is used as a roadbed material, and uses a combination of small-sized converter slag crushing and blast furnace wet dust, which have conventionally been neglected. , which promotes drying and pseudo-granulation and is intended to be used as a roadbed material.

[Means for solving problems]

In the present invention, free lime, which is contained inside converter slag particles and which weathers slowly, is pulverized and exposed, then kneaded with blast furnace wet dust, and left for one day or more to proceed with hydration and carbonation. The particles thus obtained form a solid mass and can be suitably used as a roadbed material for asphalt pavement or as a roadbed improvement material for soft ground.

The converter slag used in the present invention is optimally molten slag that has been cooled and solidified to produce crushed stone that has not undergone much weathering.

In addition, crushed stone converter slag has traditionally had relatively few uses.
．． Powder or grains of 5 cranes or less can be used.

In the present invention, powdered converter slag crushed stone of 2.5 or less grains is charged into a fret mill and crushed to expose lime (Cab), iron (Fed), etc. contained inside the particles. Next, while gradually adding wet blast furnace dust, sufficient kneading, smearing, and smearing are performed to eliminate cross-contamination that goes beyond mere surface smearing. The mixture obtained is further cured for 24 hours or more.

As a result, CaO in the converter slag and moisture in the wet blast furnace dust undergo a permanent reaction, and solidification progresses during curing. If the curing time is less than 24 hours, Ca(OH) due to hydration reaction
Since the formation of 2 and solidification due to carbon dioxide gas in the atmosphere are insufficient, curing for at least 24 hours is required.

The present invention will be explained below with reference to Examples.

〔Example〕

21.6 tons of molten converter slag was poured into a public tank, allowed to cool day and night, then dug up and crushed to produce crushed stone. At this time, particles with a particle size of 2.51 or more are considered products, and a particle size of 2.5f
Less than 1 liter of ore was discharged. The manufacturing yield was 55%.

Crushed converter slag ■140 kg with a particle size of 2.5 u or less.

■Too b, 060 kg is fret milled (capacity 1 t)
/Hr) and pulverized to 1 Ilin, then blast furnace wet dust ■60 ktr.

(1) 100 kg and (2) 140 kg were gradually added and kneaded for 5111 inches. After leaving these in an outdoor concrete floor storage area for 24 hours, their properties as a roadbed material were measured.

Table 1 shows the measurement results along with comparative examples.

In the comparative example, the shape values of crushed converter slag 40 to Ofi, which are conventionally used as upper roadbed materials, and natural crushed stone 40" 0 blind m are listed together.

As is clear from the table, it can be seen that the roadbed material obtained by the present invention has properties comparable to the upper layer roadbed material used conventionally.

Table 1 The results of the measurements are shown.

〔Effect of the invention〕

The present invention makes it possible to actively utilize finely powdered converter slag and wet blast furnace dust, which have not been used in the past.
The roadbed material obtained by this method can be comparable to natural crushed stone.

Claims (1)

[Claims] 1. Converter slag 70-50% by weight and blast furnace wet dust 30-50%
A method for manufacturing a roadbed material, which comprises mixing and kneading 50% by weight and curing for 24 hours or more.