JPS6379742A - Manufacture of colored slag - Google Patents

Abstract

(57) [Abstract] 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 for producing colored slag, which is colored differently from the original color of the slag, using molten slag as a by-product in a steel mill as a raw material.

[Prior Art] Molten slag produced as a by-product in steel mills is used, for example, as granulated slag, as a cement raw material, slag fine aggregate, or roadbed material. Since such molten slag contains sulfur and sulfides, the color of the slag obtained when the slag is cooled is usually light brown or light gray due to the sulfur content. Therefore, there was a limit to the range of use of slag.

Therefore, a technology was proposed to reduce the sulfide with a reducing agent and decolorize it, and at the same time add a coloring agent to the slag to give it a desired color.It is planned to expand the application area of slag (Japanese Patent Laid-Open No. 53-13624 In this case, specifically, ZnO is used as the reducing agent.

[Problems to be solved by the invention] Slag is usually melted at a temperature of 1400°C or higher, but even if ZnO with high vapor pressure is added to molten slag at such high temperatures, it will not react with sulfur. The rate of evaporation and disappearance without any contribution increases, resulting in a poor reaction utilization rate. However, since ZnO is expensive, there is a problem in that it is not a good idea in terms of product cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing colored slag that can efficiently desulfurize and decolorize slag and obtain beautiful colored slag. It is.

[Means for Solving the Problems] The gist of the present invention is to add a non-sublimating oxidizing agent to molten slag produced as a by-product in a steel mill to desulfurize the molten slag, and then to cool the molten slag.

In addition to the above-mentioned constituent requirements, it is possible to add a coloring agent, and if it is necessary to remove coloration due to slag Tie content or Tie content, silica sand and/or alkali may be added as a diluent. This is also an important component of the present invention.

[Function] Molten slag produced as a by-product in steel works generally has a composition range as shown in Table 1.

Table 1 (Numbers are weight %; the same applies to each table below) In this case, 3 minutes refers to the sum of the sulfur component of the sulfur compound and free sulfur. Therefore, the oxidizing agent added to the slag converts S in the slag into SO2 and removes it, and the sulfide in the slag is oxidized by the oxidizing agent. As a result, the pale brown and gray-black colors caused by S and sulfides in the slag are decolorized, and the slag takes on a pale pink color.

The non-sublimating oxidizing agent used in the present invention may be any oxidizing agent that does not volatilize or disappear and can efficiently desorb the sulfur content of the slag, such as MnO.

Examples include CuO.

The temperature of molten slag discharged from a blast furnace is usually 1450°C.
℃~1550℃, but the temperature of the slag decreases while the slag is transferred to the coloring process. Incidentally, in order for the sulfur content to be effectively oxidized by the oxidizing agent, it is preferable to maintain the temperature of the molten slag at an appropriate temperature. According to experiments conducted by the present inventors, for example, when MnO2 is used as an oxidizing agent, it has been found that the decoloring effect is efficiently performed when the molten slag temperature is 1400° C. or higher. Although there is no upper limit to the temperature of the molten slag, in consideration of energy costs and workability of mixing and stirring, it is preferable to work at a temperature of 1600° C. or lower. Therefore, for example, the slag temperature in the decolorization process can be adjusted to 1,400°C to 1,400°C using an appropriate method such as a heating temperature raising method using an electric arc furnace.
It is preferable to adjust the temperature to 600°C.

If the amount of the oxidizing agent added is less than 1%, the desulfurization effect will be insufficient, while if it exceeds 17%, there will generally be disadvantages in terms of cost, so it is preferably 1 to 17%.

Next, when the TiO2 content in the slag is high, the degree of gray or black coloration increases, making it difficult to obtain a beautifully colored slag. Therefore, silica sand and/or an alkali are added as a diluent to reduce the coloring caused by TiO2.

The molten slag that has been decolorized as described above has Cr, O
By adding colorants such as No. 5 and Coo, various colored glasses can be obtained depending on the purpose.

The molten slag may be cooled by either water pulverization or wind pulverization.

[Example] In Examples 1 to 3 below, blast furnace slag having the composition shown in Table 2 was used.

Table 2 Example 1 Blast furnace slag was melted in an electric arc furnace to a molten state of 1600°C. Add to this the oxidizing agent whose composition is shown in Table 3, and add 1 % of the blast furnace slag.
The molten raw materials added and mixed to a concentration of 5% and decolorized were then blown with pressure water to obtain a pale pink fine-grained glass slag.

Table 3 Example 2 0.5% of the slag amount of Cr, 03 with a purity of 99% or more was added to the blast furnace slag with 15% of the slag amount of Mn02 added and melted at 1600 ° C. After mixing, Cr, 03 was added in an amount of 0.5% of the slag amount, and then subjected to granulation treatment to turn it green. A colored vitreous granulated slag was obtained.

Example 3 0.2% of Coo with a purity of 99% or more was added to blast furnace slag which had been melted at 1600°C with the addition of 15% of the slag amount, followed by granulation treatment to obtain dark blue vitreous granulated slag. Ta.

Example 4 Blast furnace slag with a high TiO2 content whose composition is shown in Table 4 was mixed with silica sand whose composition was shown in Table 5 and quicklime whose composition was shown in Table 6 at 17% of the blast furnace slag. After melting at 1600℃, MnO□ from Table 3 above was added at 15% of the total raw materials, melted and mixed, desulfurized, and then subjected to granulation treatment to produce a pale pink vitreous granulated water. Got a slug.

Table 7 shows the physical properties of the granulated slag obtained in this example.

Table 4 Table 5 Table 6 Table 7 Table 7 (A) Table 7 (B) [Effects of the invention] Since the present invention is constructed as described above, it is possible to desulfurize and desulfurize slag.
By efficiently decolorizing, it is possible to obtain beautiful and transparent colored slag suitable for the purpose of the slag.

Claims (4)

[Claims] (1) A method for producing colored slag, which comprises adding a non-sublimating oxidizing agent to molten slag produced as a by-product in a steel mill to desulfurize it, and then cooling it. (2) A method for producing colored slag, which comprises adding a non-sublimating oxidizing agent to molten slag produced as a by-product in a steel mill to desulfurize it, adding a coloring agent to it, and then cooling it. (3) Adding a non-sublimating oxidizing agent to molten slag produced as a by-product at a steel mill to desulfurize it, and adding silica sand and/or alkali;
A method for producing colored slag, which comprises then cooling. (4) Colored slag characterized by adding a non-sublimating oxidizing agent to molten slag produced as a by-product in a steel mill to desulfurize it, adding silica sand and/or an alkali, and adding a coloring agent, followed by cooling. manufacturing method.