KR20060025727A - Method for treat slag of stainless steel making process - Google Patents

Abstract

The present invention relates to a method for treating stainless steel slag, the slag generated in the refining furnace and the electric furnace is cooled and crushed together with the spraying water, and the crushed slag is recovered by separation by particle size, metal components and other components, And slag can be treated irrespective of basicity and electricity.In the process of slag, it can be separated and recovered according to the particle size and metal composition of slag and recycled to be charged as a substitute for scrap in electric furnace. In addition to neutralizing the toxic heavy metals contained in the water, the water obtained in the dry sludge recovery process is recycled to other processes requiring process water.

 Stainless, smelting furnace, electric furnace, slag

Description

Method for treat slag of stainless steel making process             

1 is a flow chart schematically showing a method for treating stainless steel slag according to a preferred embodiment of the present invention;

2 is a process diagram schematically depicted for the embodiment of FIG.

<Description of Symbols for Main Parts of Drawings>

12 ... slag port 20 ... screen,

32.Road mill 58.Neutralizer unit.

The present invention relates to a method for treating stainless steel slag, and more particularly, to allow slag generated in a refining furnace and an electric furnace to be reprocessed and recycled.

Generally, an electric furnace and a refining furnace are used to manufacture stainless, and slag is generated in the electric furnace and the refining furnace.

The slag generated in the refining furnace was recycled by the dry treatment method, but this dry treatment method was not commonly applied to the slag generated in the electric furnace and the refining furnace, and also to reduce the cost of stainless steel. As the technology for lowering the basicity is being developed, there is a problem that the application range of the dry treatment method is extremely limited because the natural differentiation process used in the dry treatment method is not performed at low basicity.

The present invention devised in view of the above problems, the slag generated in the refining furnace and the electric furnace is cooled and crushed together with the spraying, and the crushed slag is recovered by separating and recovered by particle size, metal components and other components, And an electric furnace, a method of treating a stainless steel slag in which the slag is processed to be recycled irrespective of the basicity and the metal and other components in the slag are respectively recycled according to the components.

Stainless steel slag treatment method according to the present invention for achieving the above object, the slag discharged from the electric furnace and the refining furnace is crushed together with the sprinkling (撒水) cooling and crushing process; A first now recovering process for sorting slag having a predetermined particle size among the crushed slag; A crushing process in which residual slag is pulverized with watering; A secondary now recovering process for sorting sludge having a predetermined particle size from the sludge discharged from the grinding process; A dry sludge recovery process generated by recovering and water treating sludge having a predetermined particle size out of the sludge passed in the second now recovery process; It consists of a process of separating the metal now and the sulfur wood in the sludge of a certain particle size of the sludge passed in the second now recovery process;

After the second now recovery process, the sludge is neutralized using a reduction reaction further comprises.

The sludge is separated into the metal sheath and the sulfur wood by the specific gravity and the magnetic field in the recovery process of the metal sheath and the sulfur wood yarn.

The water obtained in the dry sludge recovery process is recycled to the watering in the cooling and crushing process, the sludge crushing process, and the metal now recovery process.

Hereinafter, a method of treating stainless steel slag according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are a flow chart and process diagram schematically showing a method for treating stainless steel slag according to a preferred embodiment of the present invention.

The slag treatment method according to the present invention comprises a step (S1) in which the slag generated in the smelting furnace or the electric furnace of the stainless manufacturing process is accumulated in a predetermined place, and the water is cooled and crushed together with the sprinkling water (10), and this process ( The first now recovering step (S2) for sorting the slag of the large particle size among the slag crushed in S1), and the remaining slag passed through the first now recovering step (S2) is crushed and sludged together with the sprinkling water (30) Among the sludge passed through the crushing step (S3), the second now recovering step (S4) of sorting the sludge of large particle size from the sludge discharged from this crushing step (S3), and this second now recovering step (S4) Metal sludge 60 and Hwangmoksa (62) in the large sludge sludge from the sludge recovery process (S5) of the small particle size sludge recovered and water treatment, and the remaining sludge passed through the secondary now recovery process (S5). It is made to include a step (S6) to be separated and recovered.

The cooling and crushing process (S1) is a process for allowing the slag generated in the furnace to be cooled and crushed in a short time, and the slag generated in the smelting furnace or the electric furnace of the stainless manufacturing process is stored in the slag port 12. When the water is accumulated in a predetermined place, the water is first cooled through the sprinkling water 10 of the process water, and the cooled slag is moved to a predetermined crushing work space and crushed by the breaker 14, and the water is sprinkled by the crushed slag 10. Secondary cooling takes place.

The first now recovering process (S2) is a process of selecting and collecting slag of a predetermined particle size or more out of the slag crushed through the cooling and crushing process (S1), the screen 20 that the slag can select a particle size of approximately 300mm Slag having a particle size of 300 mm or more while passing through is sorted and recovered (port now recovered; 22), and slag enough to be identified and sorted by the naked eye among the slags passing through the screen 20 is sorted by the operator. It is made to be recovered (repair now).

Of course, the repair now 24 may be made through a screen rather than an operator, and the port now recovery 22 and the repair now 24 may be recovered by being screened by a plurality of screens having respective slag sorting sizes. In the first now recovery process (S2), it is natural that the number of times of sorting slag may be made more than one or more times through a plurality of screens.

On the other hand, the crushing step (S2) is a step of regrinding the slag passed through the first now recovering step (S2), it is crushed into small particles by the differentiation and rod mill 32 while spraying the slag (30). .

In this case, the rod mill 32 may be installed in one or more so that the overlap milling operation may be performed in consideration of the particle size of the slag introduced and discharged, and other types of mills 34 instead of the rod mill 32. ) And the rod mill 32 and the grinder 34 may be disposed at the same time.

In addition, the briquette melting slag 36 and its own dust 38 collected in the crushing step (S1) is additionally added to the process may proceed.

On the other hand, the secondary now recovery process (S4) is a process for sorting the slag of a predetermined particle size or more of the sludge discharged in the crushing process (S3), while passing through the screen 40 that can select a particle size of approximately 7mm or more of 7mm or more Slag with particle size is screened and recovered (mill now) 42.

The dry sludge recovery process (S5) is a process for sorting sludge having a predetermined particle size or less among the sludge that has passed through the secondary now recovery process (S4), and passes through the classifier 50 having approximately 60 meshes, that is, sludges of 60 meshes or less. Is sorted and recovered (52), and the recovered sludge is subjected to water treatment (54) and recovered (56) in the state of dry sludge.

The components of the wet sludge before the water treatment 54 are as shown in Table 1 below.

TABLE 1 (unit wt%)

Item T-Fe C Si0 ₂ AL ₂ O ₃ Ni S T-Cr CaO MgO MnO An Pb Sample 1 0.80 0.54 25.09 2.77 0.04 0.32 1.45 58.26 6.60 1.15 0.02 0.00 Sample 2 0.81 0.51 25.00 2.78 0.04 0.31 1.50 59.01 6.65 1.20 0.02 0.00 Sample 3 0.79 0.52 25.08 2.60 0.04 0.33 1.48 58.20 6.23 1.14 0.01 0.00 Average 0.80 0.52 25.06 2.72 0.04 0.32 1.48 58.49 6.49 1.16 0.02 0.00

At this time, while being transferred to the classifier 50, it is neutralized by the neutralizing device 58 for the reduction reaction to convert the hexavalent chromium contained in the slag into trivalent chromium having a relatively low toxicity. Pulran, ferrous sulfate, sodium hydroxide, etc. are used as a neutralizing agent.

The following equation is the reduction of wastewater containing Cr6 +.

H ₂ Cr ₂ 0 ₇ + 6FeSO ₄ + 6H ₂ SO ₄ = Cr ₂ (SO ₄ ) ₃ + 3Fe ₂ (SO ₄ ) ₃ + 7H ₂ O ₂ ------- Formula 1

As shown in the above formula, in order to more reliably reduce Cr6 + in the process water, it is effective to carry out in a slightly acidic region.

The metal sludge and sulfur wood yarn separate recovery step (S6) is a process for sorting sludge having a predetermined particle size or more from the sludge that has passed through the secondary now recovery step (S4), and the sorter 50 used in the dry sludge recovery step (S5). When sludge filtered out, i.e., 60Mesh or more, is selected, the specific gravity and magnetic fields 62, 63 are used in the sludge to recover the metal now and the sulfur pastor (60, 61).

At this time, the metal choke 60 is classified into a jew (jigger choke 60a) recovered by the specific gravity 62 and a jew (charity jew 60b) recovered by the magnetic 62.

The jigger now (60a) can be used for the specific gravity classifier, which will be described in more detail, as the heavy material is submerged when the water is continuously shaken in the flow space, the light material is recovered by using the floating, chrome is It can be constructed relatively high to replace expensive raw materials of scrap in an electric furnace. Table 2 below shows the jigger now components.

TABLE 2 (unit wt%)

Item Ni Cr C Si Mn Sample 1 0.57 17.22 1.23 5.28 5.02 Sample 2 0.60 20.30 1.50 6.00 5.10 Sample 3 0.79 22.50 1.32 5.89 0.04 Average 0.65 20.01 1.35 5.72 3.39

The magnetic strip (60b) may be a magnetic separator, which will be described in more detail, by placing a magnet (permanent magnet or electromagnet) inside the cylinder is rotated in one direction to flow the sludge in the cylindrical shell metal material is a magnetic material It adheres to the cylindrical outer shell, and the non-magnetic Hwangmoksa free fall and proceeds to the post-process, the metal attached to the magnetic material is extracted and recovered by a sharp separator, the specific gravity is lower than that of the jigger (60a) It is used as an auxiliary raw material for briquetting due to the lack of metal. Table 3 below shows the components of the charity now.

TABLE 3 (unit wt%)

Item Ni Cr C Si Mn Sample 1 1.58 14.40 0.64 0.47 3.51 Sample 2 1.20 10.20 0.54 0.32 2.65 Sample 3 1.65 10.89 0.56 0.25 2.84 Average 1.48 11.83 0.58 0.35 3.00

Of course, other methods for separating and recovering the metal sheath 60 from the sludge may be used.

The sulfur wood 61 is a material obtained by separating the metal sheath 60 is mostly sand type, it is dehydrated (64) and stored in the hopper (66). Table 4 below shows the Hwangmoksa component.

TABLE 4 (unit wt%)

Item CaO SiO ₂ Al ₂ O _328.22 T.Fe MnO MgO P ₂ O ₅ S TiO ₂ Sample 1 30.41 28.22 5.84 7.35 2.60 4.33 0.06 0.16 1.06 Sample 2 32.56 29.58 5.24 6.89 2.35 4.20 0.05 0.18 1.10 Sample 2 33.30 28.30 5.63 5.23 2.45 3.98 0.06 0.15 1.23 Average 32.09 28.70 5.57 6.49 2.47 4.17 0.06 0.16 1.16

In the classification using the specific gravity and the magnetic fields 62 and 63, the classification by the magnetic field 63 may be performed after the classification of the specific gravity 62 to which the process water 65 is supplied.

On the other hand, the water obtained by the water treatment in the dry sludge recovery process (S6) during the separation and recovery process (S6), crushing process (S3), cooling and shredding process (S1) and dry sludge recovery process (S6) It is circulated to process water used in neutralization and recycled.

According to the present invention configured as described above, it is possible to process the slag irrespective of the basicity and the refining furnace and the electric furnace, and to be recycled so that it is separated and recovered depending on the particle size and metal composition of the slag in the process of slag and charged as a substitute for scrap in the electric furnace. In addition, the neutralized treatment by the neutralizing agent in the process can obtain the sulfur wood neutralized with toxic heavy metals in the slag, as well as the water obtained in the dry sludge recovery process is recycled to another process that requires the process water It works.

Claims (4)

A cooling and crushing process in which the slag discharged from the electric furnace and the refinery is crushed together with the process water; A first now recovering process for sorting slag of a predetermined particle size or more among the crushed slag; A crushing process in which residual slag is pulverized with the process water; A secondary now recovering process for sorting sludge having a predetermined particle size from the sludge discharged from the grinding process; A dry sludge recovery process generated by recovering and water treating sludge having a predetermined particle size out of the sludge passed in the second now recovery process; A process of separating and recovering the metal now and the sulfur wood from the sludge having a predetermined particle size among the sludge passed in the second now recovery process; Stainless steel slag treatment method consisting of. The method of claim 1, After the secondary now recovery step, the method for treating stainless steel slag, characterized in that the sludge further comprises the step of neutralizing treatment using a reduction reaction. The method of claim 1, The method of treating stainless steel slag, characterized in that the sludge is separated into metal and sulfur wood by the specific gravity and the magnetic field in the recovery of metal and sulfur wood yarn. The method according to claim 1 or 3, The method of treating stainless steel slag, wherein the water obtained in the dry sludge recovery process is recycled to a process requiring process water.

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