A molten slag treatment system for a molten bath smelting process

Abstract

A slag treatment system for iron bath smelting processes is characterized by comprising a slag flushing unit, a slag-iron separation unit, a dewatering unit, and a slag flushing water circulation cooling unit, with the slag-iron separation unit located between the slag flushing unit and the dewatering unit. It is primarily used to address the problem of recovering the large amount of iron carried in the slag during iron bath smelting processes. Its advantages include efficient, stable, and safe iron recovery from the slag, increasing the iron recovery rate and economic benefits; optimized process flow, avoiding repetitive dewatering steps, and rationally and orderly realizing iron recovery from the slag and the generation of finished slag, saving time and improving production efficiency; and simultaneously saving land area and infrastructure costs.

Description

Technical Field

[0001] This invention relates to a slag treatment system, and more particularly to a slag treatment system for an iron bath smelting process, belonging to the field of iron bath smelting technology. Background Technology

[0002] Iron bath smelting is a process that directly produces molten iron using iron ore powder (or other iron-containing powders) and pulverized coal. Raw materials, fuel, and flux undergo a reduction reaction within the smelting furnace. Iron oxide is reduced to molten iron, while gangue from the iron-containing material, ash from the coal, and flux fuse to form slag.

[0003] Because the feeding method of the iron bath smelting process involves injecting raw materials, fuel, and flux together or partially into the molten pool of the furnace, the reaction of these materials in the molten pool causes gushing, keeping the slag outlet zone of the molten pool in a disturbed state. This affects the complete separation of slag and iron, resulting in a large amount of molten iron mixing with the slag during the slag removal process. According to existing production data of molten pool smelting processes, the iron content of the slag produced by the furnace can reach 3% to 10%, which greatly affects the iron recovery rate in the iron bath smelting process.

[0004] Currently, there are two main methods for recovering iron from the slag produced by the iron bath smelting process, which are analyzed in detail below:

[0005] The first method is molten state separation, which is the method used in the HIsmelt molten reduction process slag recovery device (patent number 2013204980616). The slag is left to stand in the slag pot for 20-40 minutes. After the iron in the slag settles and separates from the slag, the slag and iron are poured out of the slag pot in sequence using a tilting device, thereby achieving the effect of separating and recovering iron from the slag.

[0006] The shortcomings of this molten slag-iron separation method are that the separation of slag and iron is not sufficient at the boundary, and the time required for static stratification is relatively long. The molten slag experiences a significant temperature drop in the slag pot, which increases the viscosity of the molten slag and causes slag to adhere to the slag pot, making it very difficult to achieve complete slag-iron separation.

[0007] The second method involves first quenching the molten slag in water to form a slag-water mixture, then processing it through a dewatering device to form water slag, which is then transported to a slag yard. A wet magnetic separation system is then installed at the slag yard to recover pig iron from the finished water slag.

[0008] The drawback of this method is that the dewatered slag needs to be mixed with water again before entering the wet magnetic separation system to form a slurry of a certain concentration to meet the iron removal requirements of the wet magnetic separation system. The slurry after iron removal by magnetic separation needs to enter a secondary dewatering unit for further dewatering to form the final finished slag. The secondary dewatering unit is located in the slag yard area, which can also cause pollution to the slag yard environment.

[0009] In this treatment method, the repeated dehydration process increases the project's investment and land occupation. Summary of the Invention

[0010] The purpose of this invention is to provide a slag treatment system for iron bath smelting processes. This system can solve the following problems:

[0011] 1. It can efficiently, stably and safely recover pig iron carried in the slag produced by the iron bath smelting process.

[0012] 2. Optimize the slag treatment process generated by the iron bath smelting process. The entire slag treatment process only requires one dehydration step to achieve iron recovery from the slag and the generation of finished slag.

[0013] 3. Reduce investment and land occupation for iron bath smelting process projects, and optimize the working environment of their slag treatment system.

[0014] The main concept of this invention is as follows: the slurry lifted by the primary and secondary pneumatic elevators is first fed into a slag-iron separation device for iron separation and recovery; the de-ironized slurry is then fed into a dewatering device for dewatering and slag formation. This process sequentially achieves iron recovery and the generation of finished slag.

[0015] The technical solution of this invention is a slag treatment system for an iron bath smelting process. The slag treatment system includes a slag flushing unit, a slag-iron separation unit, a dewatering unit, and a slag flushing water circulation cooling unit. Wherein:

[0016] The slag flushing unit includes a slag trench 1, a flushing box 2, an exhaust chimney in the water tank area 3, a primary V tank 4, a secondary V tank 5, a water intake well 6, a primary pneumatic elevator 7, a secondary pneumatic elevator 8, a water tank cover 9, and a primary V tank recirculation port 15.

[0017] The slag-iron separation unit includes a slag-iron separation device 10, a pig iron discharge outlet 11, and a slag slurry discharge outlet 12.

[0018] The dehydration unit includes a dehydration device 13, a dehydration device exhaust chimney 16, and a recirculation pump 14.

[0019] The slag flushing unit, the slag-iron separation unit, and the dewatering unit are connected in sequence. The primary pneumatic elevator 7 and the secondary pneumatic elevator 8 are connected to the slag-iron separation device 10, and the slurry discharge port 12 is connected to the dewatering device 13.

[0020] Furthermore, in order to ensure that the sludge-water mixture can settle stably in the pool to form slurry, a V-pool baffle 4-2 is provided in the primary V-pool 4, and a buffer grid 4-3 is provided between the end of the V-pool baffle 4-2 and the inner wall of the primary V-pool 4.

[0021] Furthermore, to prevent large pieces of slag and iron formed during water quenching from entering the bottom of the pool and affecting the discharge of slag slurry, a water quenching grid 4-1 is provided at the top of the primary V pool 4.

[0022] Furthermore, in order to optimize the working environment and prevent flue gas from overflowing in the pool, the top of the primary V pool 4, the secondary V pool 5, and the water intake well 6 are provided with the pool cover plate 9.

[0023] Furthermore, to optimize the working environment, the flue gas is centrally collected and treated, and the exhaust chimney 16 of the dehydration device is connected to the exhaust chimney 3 of the water pool area.

[0024] Furthermore, to meet the needs of different slag volume processing and equipment backup, the primary pneumatic elevator 7 can be a single unit or a combination of multiple units.

[0025] Furthermore, to meet the needs of handling different amounts of slag and equipment backup, the slag-iron separation device 10 can be a single unit or a combination of multiple units.

[0026] Furthermore, in order to achieve efficient dewatering and rapid slag formation, the dewatering device 13 is a rotary drum dewatering device or a disc dewatering device.

[0027] Furthermore, when the dewatering water cannot flow back to the water tank by gravity, a recirculation pump 14 is provided between the dewatering device 13 and the recirculation port 15 of the first-stage V tank to ensure that the dewatering water can be returned to the water tank for recirculation.

[0028] The main beneficial effects of this invention are as follows:

[0029] (1) The process of recovering a large amount of pig iron carried in the slag produced by the iron bath smelting process is efficient, stable and safe. The iron recovery rate in this process can reach more than 90%, which avoids the waste of iron resources and increases economic benefits.

[0030] (2) The process flow for treating slag generated by the iron bath smelting process has been optimized, avoiding the repetition of the dehydration process, and realizing the recovery of iron from the slag and the generation of finished slag in a reasonable and orderly manner, saving time and improving production efficiency.

[0031] (3) The slag treatment system of the iron bath smelting process has a compact layout and refined equipment configuration, which saves the land area and infrastructure costs of the process.

[0032] (4) The present invention includes a slag flushing water circulation cooling unit, which can realize cold water flushing of slag, reduce the amount of flue gas generated, realize the recycling of slag flushing water without external discharge, and improve the production environment. Attached Figure Description

[0033] This invention has appendices Figure 1 Page, 1 image.

[0034] Figure 1 This is a schematic diagram of Embodiment 1 of the present invention.

[0035] Explanation of markings in the diagram: 1—Slag trench; 2—Punching box; 3—Exhaust chimney of the water tank area; 4—Primary V-tank; 4-1—Water quenching grid; 4-2—V-tank baffle; 4-3—Buffer grid; 5—Secondary V-tank; 6—Suction well; 7—Primary pneumatic elevator; 8—Secondary pneumatic elevator; 9—Water tank cover; 10—Slag-iron separation device; 11—Pig iron discharge port; 12—Slag slurry discharge port; 13—Dewatering device; 14—Recirculation pump; 15—Primary V-tank recirculation port; 16—Dewatering device exhaust chimney; 17—Slag conveyor belt; 18—Cooling pump; 19—Cooling device; 20—Granulation pump Detailed Implementation

[0036] Specific embodiments of the present invention can be described in conjunction with examples.

[0037] In this embodiment, as Figure 1 As shown.

[0038] The working process of this embodiment is as follows: In the slag flushing unit, the slag flowing out from the end of the slag channel 1 is dispersed and granulated by the cooling water sprayed from the flushing box 2, and the resulting slag-water mixture falls into the lower primary V pool 4. A water-quenching grid 4-1 is installed below the liquid level in the slag falling area of ​​the primary V pool 4 to further impact and pulverize the slag-water mixture and prevent large pieces of slag and iron from falling to the bottom of the primary V pool 4. The slag-water mixture forms a slurry of a certain concentration at the bottom of the primary V pool 4, and flows through the buffer grid 4-3 installed between the V pool baffle 4-2 and the inner wall of the primary V pool 4 to the head area of ​​the primary pneumatic elevator 7 at the bottom of the primary V pool 4. The floating slag water above the liquid level in the primary V pool 4 overflows into the secondary V pool 5, where it settles in the head area of ​​the secondary pneumatic elevator 8 at the bottom of the secondary V pool 5, forming a slurry. The flushing water at the top of the secondary V pool 5 overflows into the suction well 6, while the slurry in the head area of ​​the primary pneumatic elevator 7 and the secondary pneumatic elevator 8 is airlifted into the slag-iron separation device 10.

[0039] In the slag-iron separation unit and dewatering unit, the slag slurry undergoes iron separation and recovery in the slag-iron separation device 10. The separated pig iron is discharged from the pig iron discharge port 11, while the de-ironized slurry enters the dewatering device 13 for dewatering. The dewatered slurry forms the final finished slag, which is transported to the required area by the slag conveyor belt 17. The de-slag water re-enters the primary V tank 4 through the primary V tank recirculation port 15 for recirculation. If, due to equipment layout or other reasons, the de-slag water cannot flow back to the primary V tank recirculation port 15 by gravity, a recirculation pump 14 can be added to pump it back to the primary V tank recirculation port 15.

[0040] In the slag flushing water circulation cooling unit, the slag flushing water in the suction well 6 is pumped to the cooling device 19 by the cooling pump 18, and the cooled slag flushing water is pumped to the flushing box 2 by the granulation pump 20 for circulation slag flushing operation.

Claims

1. A slag treatment system for iron bath smelting process, characterized in that: The processing system includes a slag flushing unit, a slag-iron separation unit, a dewatering unit, and a slag flushing water circulation and cooling unit, wherein: 1) The slag flushing unit includes a slag trough (1), a flushing box (2), an exhaust chimney in the water pool area (3), a primary V pool (4), a secondary V pool (5), a water suction well (6), a primary pneumatic elevator (7), a secondary pneumatic elevator (8), a water pool cover plate (9), and a primary V pool recirculation port (15). 2) The slag-iron separation unit includes a slag-iron separation device (10), a pig iron discharge port (11), and a slag slurry discharge port (12); 3) The dehydration unit includes a dehydration device (13), a dehydration device exhaust chimney (16), and a recirculation pump (14); 4) The slag flushing unit, the slag-iron separation unit, and the dewatering unit are connected in sequence. The primary pneumatic elevator (7) and the secondary pneumatic elevator (8) are connected to the slag-iron separation device (10), and the slurry discharge port (12) is connected to the dewatering device (13).

2. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The primary V pool (4) is provided with a V pool partition (4-2), and a buffer grid (4-3) is provided between the end of the V pool partition (4-2) and the inner wall of the primary V pool (4).

3. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The top of the primary V pool (4) is provided with a water quenching grid (4-1).

4. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The top of the primary V pool (4), the secondary V pool (5), and the suction well (6) are provided with the pool cover plate (9).

5. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The exhaust chimney (16) of the dehydration device is connected to the exhaust chimney (3) of the water pool area.

6. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The first-stage pneumatic lifting machine (7) is a single unit.

7. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The primary pneumatic lifting machine (7) is a combination of multiple units.

8. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The slag-iron separation device (10) is a single unit.

9. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The slag-iron separation device (10) is a multi-unit combined structure.

10. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The dehydration device (13) is a rotary drum dehydration device.

11. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: The dehydration device (13) is a disc dehydration device.

12. The slag treatment system for iron bath smelting process as described in claim 1, characterized in that: A recirculation pump (14) is provided between the dewatering device (13) and the recirculation port (15) of the first-stage V pool.

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