JPS58174279A - Method for recovering useful element from industrial waste - Google Patents

Abstract

PURPOSE:To accumulate and concentrate nonferrous metal contained in dust and sludge and to recover the nonferrous metal by decarbonizing the dust and sludge produced in ironworks then mixing a specific amt. of quick lime powder therewith and using the granules thereof as a coolant for iron making. CONSTITUTION:Dust or the like contg. C and S in a high rate is first charged into the thickener of a blast furnace and is thus subjected to a decarbonization treatment. The treated dust and ordinary dust or the like are mixed with 5- 30wt% quick lime powder and the mixture is dehydrated, solidified and granulated to 5-70mm. diameter. The granules are charged into a steel making furnace and are used as a coolant. Nonferrous metal in the coolant in this case is totally evaporated, but said metal is cooled to solidify and again granulated. The granules are again used as the coolant. Thus, the nonferrous metal is concentrated and the nonferrous metal is recovered economically on a commercial base.

Description

[Detailed Description of the Invention] This invention effectively utilizes dust and sludge generated in steel works, etc. to recover Pζ 0, and also to recover useful metals contained therein in an economical and effective manner. The present invention relates to a method for producing a refining raw material by concentrating the

There are various types of dust and sludge that are generated in steel works, etc., and the amount generated varies depending on the fl type of raw materials, blending ratio, work method, and recovery method. Table 1 shows the basic units of production and production.

Table 1 Type Generation unit Kg/'1' Blast furnace thickener sludge 2.0 to 6.0 Converter thickener to sludge
10.0-15.0 rolling thick nurse 2 1.
0~5.0 Sintered gravel dust 1.0~4.0
Mixed pig iron furnace dust 0.1~1.5 Converter furnace dust 0゜5~1.5 This data is just one example, but if you add up the dust and slurry generated at steel plants, The amount is the amount of crude steel produced by a steelworks.
This corresponds to i2-4-.

Below, all weights and ratios mentioned in the specification refer to those in a dry state.・The content is usually 50 to 70%. Despite this, these materials are not currently being reused effectively for the reasons described below.

(1) If something that normally contains oil, such as rolling sludge, is reused, its vapor will adhere to the inside of the dust collector and cause failure.

(2) Dust and slurry contain large amounts of zinc, potassium, sodium, etc., and if they are reused as raw materials for ironmaking, it will be possible to prevent the formation of cracks in the wall of the blast furnace shaft, especially in the middle section. This is the main cause of furnace wall deposits called PL. When this develops, the profile inside the furnace changes significantly, inhibiting the stable operation of the blast furnace by inhibiting the smooth descent of the burden.

(5) Also, as the wall formation occurs, the gas distribution in the furnace changes, which may cause wall collapse, which may cause problems such as damage to the tuyeres and cooling of the hearth.

(4) If blast furnace sludge, pig iron mixer dust, and other materials with a high content of 8% are reused as they are, the 8% will dissolve into the pig iron and steel, leading to deterioration of the physical properties of the pig steel. Removing K requires a huge amount of effort and expense.

(5) Dust and slurry usually have a particle size of 0.1
Items of 49 mm or less are extremely difficult to handle because they are powders that account for 90 to 99 inches, and sludge-like items that have been treated with water to 4% dry out very lumpy, so it is difficult to handle them. requires a great deal of effort and expense.

For the above reasons, these dusts and slurries are
・Despite its low content, until now it has hardly been reused and has been dumped into dumpsters as industrial waste.

However, dumping these wastes involves securing a dumping site, various problems caused by the dumped materials, transportation and cost issues, etc. The problem of processing and reusing these industrial wastes is a common problem in the steel industry. The present invention is intended to solve the various problems explained above, and it is possible to recycle the aforementioned waste, which conventionally had to be disposed of unavoidably, and whose disposal itself was wood acid. A method to fully recover and utilize not only Pe but also active ingredients such as C2Mn, while at the same time concentrating metals that were previously considered harmful to steelmaking operations in sludge, and raising it to a profitable grade raw material. It provides:

Table 1 shows typical examples of types and basic units of dust, slag, etc. that are generated at O steelworks, etc., which are generated at steelworks that produce 18.5 million tons of crude steel per year. These examples 1 and 2 are shown in Table 2, and their compositions and moisture contents are shown in Table 3.
゛Generated raw material unit -/T Monthly generation amount T Blast furnace sludge 5.0 5562 Converter sludge 12.2 8729 Pressurized sludge
2.1 1461 sintered dust
2.2 2033 Mixed pig iron furnace dust 0.5
546 converter dust 1.0
As shown in Table 2 of Table 3 of 716, the monthly amount of dust and slurry generated in a steelworks of this scale is 16,847 tons/month.
As shown in Table 5, although the average value of F・min is 57-4, Zn1.7chi, K+Ma1. It was impossible to use Q-moor reeds as a raw material for blast furnaces.

Also, the moisture content was 29% on average, making it unsuitable for reuse.

The present invention aims to conveniently use a dust and sludge mixture with a high moisture content as an auxiliary raw material for steelmaking.
It is characterized by passing through the following steps as its pretreatment.

In other words, 50-50% of blast furnace thickener sludge is made up of cozes, and if it is used as a steelmaking coolant as it is, there is a risk that the desulfurization ability will be significantly inhibited by the 8 in coke.
In addition, in order to separate and effectively utilize coke, which can be used as a valuable energy source, ore beneficiation is carried out as a pre-processing process.The 7 bales of 56 ore are produced using the known Tsubami d-densification method, flotation method, and magnetic ore beneficiation method. A 0-2 example is shown in which one 5rL4A group τ is equal.

Implementation f11 Flotation legal amount? , Chizn-0% Feed ore 100 22 8 58 Floating ore 40
2 5 82 Ore deposit 6035119 Concentration 2 Magnetic ore beneficiation method 100 26 3 46 Magnetic ore 2
8 54 2 6 Non-magnetic ore 72, 15
362 The beneficiation conditions may be determined by considering equipment, cost, yield, etc. Table 4 below shows examples of ore separation and decarburization using a strong magnetic field type magnetic separator. In this case, O
It is recommended that the mixed pig iron furnace dust with high S content be mixed with the blast furnace thickener and decarburized.

4th representation: o Zn s amount i blast furnace sludge 32.7 Leap, 5 3.4
0.64 3562 Mixed pig iron furnace dust 47.0
1B, 5 0.2 0.42 546 mixed sludge
34.0 36.7 5.10.62 590
8 Magnetic object 57.8 6.0 1.60.121954
Non-magnetic object 10.2 67.4 4.6 1.12
1954 The non-magnetic material obtained by this treatment has a high O content and is fully suitable as a raw material for general fuels.

The magnetic material thus obtained, other low C, 8 dusts and slurries, and in addition 5 to 50 grams of quicklime powder are mixed, mixed, and reacted and dehydrated by a commonly known method. At this time, the moisture contained in the dust and sludge reacts with the quicklime powder, and the intense exothermic reaction that occurs at this time evaporates the moisture and solidifies it as Ca(OH)2. At this time, the amount of quicklime powder added may be adjusted as appropriate depending on the desired moisture content of the product.

The thus dehydrated and solidified cross-wire solid is granulated to a diameter of 5 to 70 mm by various known methods, and then cured for several days if necessary to form a finished product.

During steelmaking, this product is used as a coolant to maintain the molten steel temperature or as a decarburization slag agent. In addition to lowering the C
aO increases the basicity of steel slag, dephosphorizes and desulfurizes it, and removes Fe.
The minutes are 11! In addition to serving as an oxygen source, p10 enters the steel, and part of the iron oxide produces ferrite, which promotes the slag formation of lime.

Zn K Na and the like contained in this product are immediately vaporized in their entirety by being put into a high-temperature furnace, and are discharged from the furnace together with the exhaust gas, where they are collected by a cooling solidification machine. in this case:
K and M are compounds in various forms, but in the case of water washing, they are dissolved in water in the form of ions and discharged.

All oil is burned or vaporized and discharged from the furnace, and either enters the exhaust gas or dissolves in the dust collection water.

Most of the Zn goes out of the system and enters the converter dust and slurry.

Therefore, by repeating the cycle of producing and using this coolant, the 4 content in the dust slurry generated from the steelmaking furnace gradually accumulates and becomes concentrated.

To explain using the example in Tables 2 and 3, the content of dust and slurry produced by 16,847 ducks per month is 1.7-128
It was 7 tons. Among these, as a result of magnetic separation of blast furnace slurry and mixed iron furnace dust, the magnetic substances and other dust, steelmaking furnace,
In the example, when the zn content in the converter flage is put into the converter, decomposed and dust-collected, and recovered as converter slurry, the Zn content in the converter flage is 3.7-
Became.

In this way, by granulating dust and sticks, feeding them into the steelmaking furnace as a coolant, collecting the dust, and cycling it for repeated use, it is possible to cumulatively improve the occurrence of 6zn in the coolant. It is.

In summary, the main point of the present invention is to treat dust and sludge generated from steel works, etc., which have been difficult to dispose of in the past. Of the East waste, those with high 01B values, such as blast furnace slurry and mixed iron furnace dust, are first treated with beneficiation, most of the 0 and H are separated and used as energy sources, and the rest is used as other dust and slurry. By mixing an appropriate amount of quicklime powder into it and stirring it, the granulated product is used as a steelmaking furnace coolant.
In addition to directly recovering the active ingredients contained in dust and sludge during steel manufacturing, the components that are decomposed and evaporated from the coolant and collected again are collected by repeating the cycle of dust collection, solidification, granulation, and injection. Concentrate and remove components other than iron, in this example Z
n f) It is provided as a raw material for G-line.

Although zinc as a raw material for refining varies depending on the economic situation, according to this method, which normally requires a quality with a Zn content of 30% or more, the initial 28 minutes in the converter flage is 1.5 - However, by using this method, it became possible to raise the economic quality to four raw materials in about one year.

As described above, the present invention can bring about great effects by implementing it. That is, by carrying out the present invention, the amount of industrial waste is reduced, disposal costs are reduced, and the effective ingredients contained in the waste can be recovered and used without waste.

The benefits of this invention are extremely large for both the steel industry, where industrial waste disposal and disposal are a major problem, and the zinc smelting industry, which faces various problems due to raw materials.

Patent applicant Fuji 1) Toshihiko

Claims (2)

[Claims] (1) Among the dust and sludge generated in steel works, etc., blast furnace thickener sludge generated in the ironmaking process,
A method in which most of the 0 is extracted by beneficiation of dust and sludge with high 0 and S, and the remaining sludge after the fatigue coal treatment is used in the step (2). (2) Based on (1) - Quicklime powder is mixed in the range of 5 to 30% with decarburized sludge and dust and streaks generated in the steelworks, and this is kneaded, granulated, and cured to produce steel. Useful materials from industrial waste characterized by recovering iron by using it as a coolant and cumulatively concentrating other non-ferrous metals by repeating the same operation within the system to obtain raw materials of profitable grade. Element recovery method◇