JPS59121153A - Manufacture of refractory raw material from aluminum 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 The present invention utilizes a thermite reaction between metallic aluminum in the aluminum slag and iron oxide in the scale to create a mixture of aluminum slag and scale, so that spinel crystals coexist. The present invention relates to a method for producing a large-sized raw material that is α-alumina crystal.

Aluminum slag generated during smelting of metal aluminum or melting scrap aluminum, aluminum alloys, etc., and heating of continuous casting, steel ingots, steel billets, etc. during the manufacture of steel products.

Rolling 2. Scales generated from processes such as forging.

Some of these are recovered as aluminum and iron or used for other purposes, but a significant amount is disposed of as industrial waste. One purpose of the present invention is to use materials with such properties as raw materials, to make almost all of their constituent materials more valuable, and to produce them using a large amount of thermal energy. Another objective is to produce refractory raw materials and steel that can be substituted for fused alumina, by effectively utilizing the reaction heat of the thermite reaction, and greatly reducing the thermal energy input from the outside. It has two purposes:

What is the aluminum slag targeted by the present invention?

For scouring metal aluminum, melting scrap aluminum, melting aluminum alloys, etc.

The aluminum slag used in the two-piece production method is mainly composed of oxides that emerge on the surface of the melt, but it is crushed and sieved, and M-A is used to cause thermite reaction.
j' must be contained in an amount of 20% or more, and the fewer the impurities harmful to the refractory raw material, the better, so it is desirable to adjust the chemical composition as shown in the table below.

On the other hand, the scale targeted by the present invention is when molten steel is continuously cast and the steel billets are drawn out and cooled.

This occurs when steel ingots, steel slabs, etc. are heated in a heating furnace for rolling or forging, and when they are rolled or forged. Although the scale is mainly an oxide of iron, it is desirable that the scale used in the two-piece production method contains 70% or more Fe and is dried to a moisture content of 0.5% or less and made into fine particles.

The present invention uses the aluminum slag and scale described above in 9 as raw materials, and effectively utilizes the composite effect of their combination. That is, due to the thermite reaction between metallic aluminum in the aluminum slag and iron oxide in the scale, metallic iron, alumina, and a large amount of reaction heat are generated by reducing the iron oxide and oxidizing the metallic aluminum. The reaction formula and reaction heat amount in this case are shown below.

△)('(cal/m0l-A7203)2Ae+Fe
203 = 2Fe +A1203-194,8002
A/+7Fe304=7Fe+Ar203-189.8
002Ae+3FeO=3Fe+Ae203-197
,300The heat generated by this thermite reaction is.

Since it can be used as a heat source for melting raw materials and reaction products, it is possible to reduce the amount of thermal energy input from the outside. Furthermore, if the amount of scale blended is adjusted, the thermite reaction can also occur between metallic aluminum in the aluminum slag and metal oxides such as Si02, which are harmful to refractory raw materials contained in the aluminum slag. Metal oxides are reduced to metals, which are melted into the reduced iron through the thermite reaction and become alloyed iron, which sinks to the bottom due to the difference in specific gravity, so these metal oxides do not remain in the slag, and aluminum slag N21 remaining inside.
K, Mg.

Chlorides such as Ca and AJN are decomposed or volatilized by the high-temperature heat generated by the thermite reaction, and a molten product containing extremely few impurities harmful to the refractory raw material is obtained.

A portion of the MgO contained in the aluminum slag evaporates due to the high-temperature heat generated by the thermite reaction, but most of it is vaporized by AI!
2 oa to form spinel (M gO-Aj'20
3) Generate. It was discovered that the slowly cooled slag obtained by coexisting spinel crystals with α-alumina crystals has lower porosity and higher bulk specific gravity than fused alumina, improving its properties as a raw material for refractories. .

The steel produced by the method of the present invention is directly poured into a mold or used as a raw material for steel making, cast iron melting, etc. The produced special slag is slowly cooled and spinel crystals coexist with α -Grow alumina crystals,
This is crushed and sieved to become an excellent raw material for refractories.

As described above, the present invention is a manufacturing method that is very useful for saving resources, saving energy, and preventing pollution, and has extremely large industrial effects.

Examples The raw materials used are crushed and sieved aluminum slag and scale. The chemical compositions of these raw materials are shown in Table-1.

20 Ky of the aluminum slag and 24 kg of scale were mixed using a mixer to obtain mixed raw materials 44 and 9.

Meanwhile, electrode scraps are put into the electric furnace. When power is then supplied to the electric furnace, an arc is generated between the electrode and the hearth. After this arc stabilizes.

The above mixed raw materials are gradually added. Mixed raw materials.

It melts while causing a thermite reaction. After putting all of the above mixed raw materials into the electric furnace, when the thermite reaction is finished and the temperature of the molten material in the furnace reaches 2100°C, the power supply to the electric furnace is stopped, and the heat insulating material mainly contains alumina. 20 to 9 into the furnace to cover the surface of the melt. The melt is slowly cooled in this heat-retained state to grow α-alumina and spinel crystals.

In the furnace, the solidified product has completely separated iron at the bottom and slag at the top. The solidified iron and slag were taken out by disassembling the electric furnace. This lumpy iron is used as an iron source, and the slag, after being crushed, is used as a raw material for refractory bricks and as an aggregate for castable refractories.

The chemical composition of the produced iron is shown in Table 2 below.

The chemical composition of the produced slag is shown in Table 3 below.

When the above slag was analyzed by X-ray diffraction, some Aj'
z○3 and MgO chemically combine to form spinel (Mg0
-AI! 203). Also, Al2O3
are all α-alumina crystals.

As shown in the attached diagram, spinel minerals were observed surrounding the α-alumina crystals as a result of microscopic observation of the slag. Also, add 3.36 to 1.68 ffl of the above slag.
The porosity and bulk specific gravity were measured after pulverizing to ffl, and the porosity was 2.5 to 3%, and the bulk specific gravity was 3.75 to 4. The porosity of fused alumina is smaller than 4.5% to 4.8%, and the bulk specific gravity is larger than 3.72. The weight of iron produced is 17. I
Kp, the weight of the refractory raw material was 23.1Kg, and the power consumption was 4.2KWH.

In a method of reducing scale using coke or the like to produce the same amount of iron, the cost is approximately 3.4. The method of producing the same amount of fused alumina from bauxite consumes about 58 K W H of electricity, compared to the total power consumed by these methods of 92 K W H. It can be seen that the invention method consumes less power.

[Brief explanation of the drawing]

The attached figure is a microscopic photograph of the raw material for the figures. S: Spinel mineral α: Alpha alumina crystal Tokushu Hiroken people j7:2 needle Hiroshi 7MK’L “flJPL+1” J Te Zhu Chiang Length Body Protection Tetsutomo

Claims (1)

[Claims] By using a mixture of aluminum slag and scale with an igniter, electric arc, high-temperature heating, or a combination thereof, the thermite of metallic aluminum in the aluminum slag and iron oxide in the scale is produced. By causing the reaction and at the same time efficiently melting the reaction product and additives. Due to the thermite reaction between metal oxides such as ≦i62 contained in aluminum slag and metal aluminum,
Harmful metal oxides are reduced to refractory raw materials, and metals such as Si are absorbed into the iron produced by scale reduction. The aluminum slag is separated at the bottom due to the difference in specific gravity, and the high-temperature heat generated by the thermite reaction is used to decompose or volatilize the chlorides and nitrides contained in the aluminum slag, and then the melt is slowly cooled. A method for producing a refractory raw material from aluminum slag, characterized in that the refractory raw material is made by growing α-alumina crystals in which spinel crystals coexist.