JPS6321226A - Production of high purity starting material for ferrite - Google Patents

Abstract

PURPOSE:To produce iron oxide as high purity starting material for ferrite at a low cost by collecting converter dust with a heat resistant filter, bringing air into contact with the dust to oxidize the dust, removing the oxidized dust from the filter with a regenerating gas and recovering the dust. CONSTITUTION:Exhaust gas generated from a converter 1 during refining by blowing is introduced into a dust oxidizing collector 3 through a gas recovering duct 2, and converter dust in the exhaust gas is stuck to a heat resistant filter 4 and recovered. The dust-free exhaust gas is sucked with a suction fan 13 through a gas cooler 10, and a three way valve is properly controlled to feed the gas to a combustion and diffusion tube 11 or a gas holder 12. The converter dust on the filter 4 is oxidized by bringing air into contact with the dust, and the oxidized dust is scattered by blowing air on the rear side of the filter 4 from regenerating nozzles 9 through a connecting pipe 8 for regenerating the filter. The oxidized dust 5 accumulated on the bottom of the collector 3 is then sent from the bottom to an iron oxide separator 7 through a discharge value 6 and impurities are removed to obtain starting material for ferrite having about 99.7-99.9% Fe2O3 content.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a high-purity ferrite raw material, in particular, after further oxidation treatment of converter dust generated in converter blowing, Pe203 min. The present invention relates to a method for producing a high-purity ferrite raw material from converter dust, which is purified and recovered and used as a ferrite raw material.

(Prior Art) As is already well known, the exhaust gas of an oxygen converter contains a large amount of dust, about 100 g/Nm3, as so-called converter dust.

These converter dusts must be removed for exhaust gas treatment, and have conventionally been removed using a wet type Henchuri scrubber or the like.

And, as shown in Table 1', more than 90% of the wet collected dust collected by these dust removal methods is FesF.
Since it is eO, it is further processed and recovered in a thickener as an iron source, and after going through a sintering process, it is used as a raw material for ironmaking, contributing to improved yields in ironmaking.

In general, the iron content in converter dust is caused by humus loss, which occurs when molten steel is blown with oxygen in a converter at a temperature of 2,000 degrees Celsius, where some of the iron evaporates and hardens, or bubbles form on the surface of the stirring flow, which break and cause iron to fly. Occurs due to burst phenomenon.

In addition, when the dust is rapidly cooled with water using, for example, a Hentury scrubber, the iron content (Fe) in these dusts becomes FeO (Fe:0 = 1:1), FeO (Fe: 0 = 1: 1), Fe
, 0. (Fe:0 = 3:4), and further FezO1 (
It is known that Fe:O exists in the form of 2:3).

Table 1 below shows an example of the composition of converter dust collected by wet method, and it can be seen that most of the dust is present in the form of FeO and Pe.

Table 1 (wt%) Regarding the usage of converter dust, there are other ways to use converter dust, such as those generated in a pure oxygen blowing converter equipped with gas recovery equipment, as disclosed in JP-A-54-127810. Focusing on the high content of iron in converter dust and the hardness of metallic iron, it is possible to collect converter dust, classify it, and use coarse metal powder as shot or grit for shot blasting. Proposed.

(Problems to be Solved by the Invention) However, even if the iron recovered from these converter dusts is used as a raw material for ironmaking, it will contribute to improving the yield of steelmaking;
It could only be evaluated as a raw material for iron making.

In addition, the method of using it as shot blasting, which is an alternative method, simply focuses on the high content of metallic iron powder in the converter dust and its high hardness, so to speak, the characteristics of the starting material are simply evaluated. \Just to use it.

(Means for Solving the Problems) Therefore, the inventors of the present invention have repeatedly investigated ways to effectively utilize the iron content in these converter dusts with higher added value. We focused on the fact that the Fe content in the furnace dust was extremely high.

Furthermore, the present inventors found that such a high concentration of iron in the converter dust contains many incomplete iron oxides such as Fe and FeO, and that according to the dry recovery method, the high-temperature state (1000 to 7
Focusing on the fact that it easily becomes a complete oxide because it is recovered at 00°C), we conducted further experiments and found that the F+403 min obtained in this way had a purity of over 99%, which is suitable as a raw material for ferrite production. The present invention was completed based on the finding that this is optimal.

Here, the gist of the present invention is to collect converter dust generated in converter blowing by attaching it to a heat-resistant filter,
Next, the heat-resistant filter to which converter dust is adhered is brought into contact with air to undergo oxidation treatment, and the oxidized converter dust is removed and recovered from the heat-resistant filter using heat-resistant filter regeneration gas. :+)
This is a method for producing high-purity ferrite raw material from converter dust, which is characterized by recovering high-purity fractions as ferrite raw material.

In addition, the high purity Fe2O3 recovered in this way is
Normal purity can be easily increased to 99.8%,
Therefore, a ferrite raw material can be obtained by conventional means, and ferrite produced in this way is extremely inexpensive, which will greatly contribute to its widespread use.

(effect) The present invention will now be described in detail using the accompanying drawings.

The attached drawing is a schematic diagram for explaining the steps of the method according to the present invention. The converter dust is supplied to a dust oxidation collector 3 equipped with a filter 4 inside, and at that time, the converter dust adheres to the heat-resistant filter 4 and is collected.

After converter dust is removed from this exhaust gas by a heat-resistant filter 4, it is purified, guided to a gas cooler 10 by a suction fan 13 installed between a damper and a three-way valve, and cooled. 10 and suction fan 1
By opening the damper provided between 3, the suction fan 1
Gas holder 1 passes through the three-way valve from 3 to the three-way valve.
2 is collected as regeneration gas.

In addition, the cod of the exhaust gas cleaned by the heat-resistant filter 4
If the CO concentration is low, by knowing that the CO concentration is low, for example, by using a Co @ temperature meter (not shown) or other means installed between the gas cooler 10 and the damper.
The damper is opened, the CO gas is guided from the suction fan 13 to the three-way valve, and the CO gas is combusted and diffused from the three-way valve through the combustion and diffusion pipe 11.

Incidentally, the converter dust contained in the exhaust gas is deposited in a high-temperature dry state on the heat-resistant filter 4 installed in the dust oxidation collector 3 during the normal converter processing time of about 20 minutes. Oxygen-containing gas such as air is brought into contact with the deposited converter dust to perform oxidation treatment. In particular, in the case of the present invention, since air is sucked into the converter l after the blowing is completed, ambient air enters from the downstream side without using any other contact means and continuously blows against the heat-resistant filter 4. Then, the dust may be completely oxidized by oxygen in the air to become oxidized dust. Of course, an appropriate air blowing means may be provided.

The time required for the oxidation treatment of the converter dust is from 5 to 50. After complete oxidation is completed on the surface of the heat-resistant filter 4 and in the dust oxidation collector 3, the damper at the inlet of the suction fan is closed. Then,
Air driven by a fan is sent as filter regeneration gas from a regeneration nozzle 9 connected to an external fan on the opposite side via a connecting pipe 8 to the blowing surface of the heat-resistant filter 4 provided in the dust oxidation collector 3. The oxidation dust attached to the dust oxidation collector 3 is blown off to the bottom of the dust oxidation collector 3,
It is separated and removed from the heat-resistant filter 4, deposited on the bottom surface, and collected.

Further, the oxidized dust 5 deposited on the bottom surface of the dust oxidation collector 3 is appropriately cut out to the iron oxide separator 7 using the cut-off valve 6, and the iron oxide separator 7 removes impurities to remove FezO from the oxidized dust 5. = high purity. These impurities may be removed by a gravity separation method such as table beneficiation.

The highly purified Fe2O3 is transferred to the iron oxide separator 7.
A high purity ferrite raw material can be obtained by recovering the raw material from the ferrite. Usually, the Fe2O* purity at this time is 99.7-9
It is 9.9%.

Next, the present invention will be explained with examples.

Example In this example, converter blowing treatment was performed for 20 minutes in a 250-ton converter using the apparatus shown in the attached drawings. The amount of converter dust collected from this converter into the dust oxidation collector is 2800 k
g/ch. The component composition of this converter dust was as shown in Table 2.

In addition, after blowing, air was blown onto the converter dust collected by adhering it to a heat-resistant filter (800° C.) for 5 minutes to oxidize it, and then the filter was regenerated and collected. The composition of the fully oxidized dust collected by the dust oxidation collector is shown in Table 3.

Table 2 (% by weight) (% by weight) Next, impurities were removed from these fully oxidized dusts by conventional table beneficiation. The component composition of the final product highly purified in this way was as shown in Table 4.

As mentioned above, while the amount of dust recovered from the 250 ton converter after converter blowing was 2800 kg/ch, the amount recovered of the final product shown in Table 4 was 2350 kg/ch. Therefore, the final recovery rate was approximately 80%.

(Effect of the invention) As described above, according to the present invention, 80% of the total amount of converter dust
% or more is recovered as Fetus, and its purity is 99.8% or more, so it is sufficient as a ferrite raw material, and it is inexpensive.
The benefits of the present invention are significant.

[Brief explanation of the drawing]

The accompanying drawings are schematic illustrations of the steps of the method according to the invention.

Claims (1)

[Claims] Converter dust generated in converter blowing is collected by attaching it to a heat-resistant filter, and then the heat-resistant filter to which the converter dust is attached is brought into contact with air to undergo oxidation treatment, and the converter dust is obtained by performing this oxidation treatment. A method for producing high-purity ferrite raw material from converter dust, characterized in that iron oxide (Fe_2O_3) is recovered in high purity as a ferrite raw material, comprising removing and recovering iron oxide (Fe_2O_3) from the heat-resistant filter using heat-resistant filter regeneration gas. .