Treatment method of molten iron desulfurization slag

Abstract

The invention belongs to the technical field of desulfurization slag treatment, and discloses a molten iron desulfurization slag treatment method which is characterized in that desulfurization slag is subjected to hot disintegration treatment in a hot disintegration mode, the humidity is increased while the desulfurization slag is cooled, a large amount of dust is prevented from being raised when the desulfurization slag is turned out of a slag tray, and meanwhile slag-iron separation of the desulfurization slag is better achieved. According to the method for treating the molten iron desulfurization slag in the hot disintegration mode, the water cooling treatment period of the desulfurization slag can be shortened to be within 4 hours from 8-12 hours, the treatment period of the desulfurization slag is greatly shortened, and normal operation of production is guaranteed; the desulfurized slag subjected to hot disintegration treatment is good in slag-iron separation effect and high in slag-iron recovery rate, and 10.52% of desulfurized slag iron can be recovered from the desulfurized slag treated according to the method; meanwhile, flying dust can be well controlled in the overturning and transferring process of the desulfurization slag subjected to hot disintegration treatment, and it is guaranteed that treatment of the desulfurization slag reaches the environment-friendly requirement standard.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of desulfurization slag treatment, and particularly relates to a treatment method of hot metal desulfurization slag. BACKGROUND

[0002] In iron ore smelting, hot metal with a sulfur content of more than 0.050% by weight needs to be desulfurized outside the furnace before entering the converter for steelmaking, and the desulfurization slag on the surface of the hot metal is scraped off after desulfurization using a slag scraping process. In particular, in vanadium-titanium magnetite smelting, a large amount of desulfurization slag is generated every year due to the high sulfur content of the hot metal.

[0003] The desulfurization slag scraped off from the surface of the hot metal is in a high-temperature semi-solid state, and most steel plants currently use a method of directly turning over the desulfurization slag after static cooling, but this method causes serious dust and pollution, and has a serious impact on the working environment and the health of the on-site operators.

[0004] The water cooling process is one of the most commonly used and most economical methods for treating hot molten steel slag in the steel industry, which uses the intense heat exchange and physical and chemical reactions that occur when water comes into contact with high-temperature steel slag to achieve the purpose of cooling and fragmentation. However, the CaO content in the desulfurization slag is relatively high, and the reaction of calcium oxide with water and carbon dioxide generates calcium carbonate, so water cooling forms a crust on the surface of the slag. In the case of a large amount of water, the slag surface quickly forms a crust, preventing water from penetrating downward, resulting in water accumulation in the slag pan, and water cannot effectively penetrate into the interior of the slag pan, so the desulfurization slag at the bottom and center of the slag pan is still in a red slag / candy core state, and explosion is likely to occur during the slag turning process. In the case of a small amount of water, the desulfurization slag cannot be effectively cooled, and the desulfurization slag at the bottom and center of the slag pan is in a red slag state for a long time, failing to achieve the cooling effect.

[0005] In order to avoid water accumulation in the slag pan while achieving the cooling effect, the amount of water and the watering time need to be controlled, resulting in a long processing time (usually 8-12 hours) for water cooling of the desulfurization slag. In addition, the sulfur content of the hot metal produced by vanadium-titanium magnetite smelting is relatively high, and in the case of a sulfur content of more than 0.15% in the hot metal, the amount of desulfurization slag is large, and the capacity of a desulfurization slag pan is only about 12 t. In order to ensure that there is enough space for water accumulation and that the desulfurization slag is not washed out of the desulfurization slag pan, the loading capacity of the desulfurization slag can only be controlled at about 6 t. The capacity of the desulfurization slag pan is limited, and in the case of a large amount of desulfurization slag, the water cooling method for the desulfurization slag cannot ensure the normal turnover of the desulfurization slag pan. SUMMARY

[0006] Therefore, the present application aims to provide a treatment method of hot metal desulfurization slag to solve the problems of a long processing period and a low slag-iron recovery rate in the existing treatment process of hot metal desulfurization slag.

[0007] In order to achieve the above technical effects, the application provides a molten iron desulfurization slag treatment method, which comprises the following steps: Step 1, the desulfurization slag scraped from the molten iron liquid surface is put into a desulfurization slag tray; Step 2, the desulfurization slag tray in step 1 is put into a hot steaming box; Step 3, the desulfurization slag is cooled in the hot steaming box in a manner of “watering-hot steaming”, the circulation number is at least three times, the circulation time is 1 h each time, and the watering time is 6-30 min in each circulation.

[0008] Further, in the preferred embodiment of the application, the added amount of the desulfurization slag in the desulfurization slag tray in step 1 accounts for 1 / 2 of the volume of the desulfurization slag tray.

[0009] Further, in the preferred embodiment of the application, the circulation number in step 3 is four times.

[0010] Further, in the preferred embodiment of the application, the watering amount of the first circulation in step 3 is watering for 6-20 minutes at a flow rate of 6-7 m 3 / h, and the watering amount of the remaining three circulations is watering for 6-20 minutes at a flow rate of 3-4 m 3 / h.

[0011] Further, in the preferred embodiment of the application, the watering amount of the first circulation in step 3 is watering for 30 minutes at a flow rate of 6-7 m 3 / h, and the watering amount of the remaining three circulations is watering for 30 minutes at a flow rate of 3-4 m 3 / h.

[0012] Further, in the preferred embodiment of the application, when the temperature of the hot steaming box is lower than 30℃, the circulation is stopped, and the desulfurization slag is checked after the box is opened.

[0013] Further, in the preferred embodiment of the application, the checking of the desulfurization slag after the box is opened comprises checking the emission of water vapor and the red slag of the desulfurization slag.

[0014] The desulfurization slag is a waste produced when the molten iron is subjected to desulfurization pretreatment before entering a steelmaking furnace, and the main components are Fe, CaO and a small amount of MgO, Al2O3, SiO2 and other compounds. Because of high content and high temperature at the time of production, the desulfurization slag is in a red slag state, and most of it is in a dust state after air cooling, which has a great impact on the environment during treatment and transportation. Therefore, the application adopts the form of hot steaming to hot steam the desulfurization slag, so that the desulfurization slag is cooled while the humidity is increased, the dust is avoided when the desulfurization slag is turned over from the slag tray, and the separation of slag and iron of the desulfurization slag is better achieved.

[0015] In summary, compared with the prior art, the present application has the following advantages: The method for treating hot metal desulfurization slag in a hot leaching manner provided by the present application can shorten the water cooling treatment period of the desulfurization slag from 8-12 hours to less than 4 hours, greatly shortening the treatment period of the desulfurization slag and ensuring normal operation of production; the desulfurization slag after hot leaching treatment has good slag-iron separation effect and high slag-iron recovery rate, and 10.52% of the desulfurization slag iron can be recovered from the desulfurization slag after treatment according to the method of the present application; at the same time, dust in the overturning and transporting process of the desulfurization slag after hot leaching treatment can be well controlled, so that the treatment of the desulfurization slag meets the environmental protection requirement standard. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0017] The present application provides a method for treating hot metal desulfurization slag, which comprises the following steps: Step 1: placing the desulfurization slag scraped from the liquid surface of the desulfurized hot metal into a desulfurization slag tray; Step 2: placing the desulfurization slag tray in step 1 into a hot leaching box; Step 3: circulatingly cooling the desulfurization slag in the hot leaching box in a manner of “watering-hot leaching”, wherein the circulation number is at least two times or more, the circulation time is 1 hour each time, and the watering time is 6-30 minutes in each circulation.

[0018] The composition of the desulfurization slag is shown in Table 1 below.

[0019] Table 1. Composition table of desulfurization slag

[0020] Specifically, the added amount of the desulfurization slag in the desulfurization slag tray in step 1 is about half of the volume of the tray (equivalent to: estimated with hot metal S=0.140%, the number of slag tapping furnaces is about 4).

[0021] When the added amount of the desulfurization slag meets the requirement, the slag car is opened to the slag yard by the pre-treatment slag scraping worker, the hoisting is informed to the crane worker, and the hot leaching of the desulfurization slag is implemented by the recovery shift of the preparation workshop, and the hot leaching box number is arranged by the recovery shift of the preparation workshop at the same time.

[0022] Further, the specific operation of step 1 is as follows: 1.1, desulfurization slag transfer at the slag tapping position 1.1.1-First use the chain hook to hang the chain, then hoist the desulfurization slag tray to the side of the mountain; 1.1.2-When the pre-treatment slag worker hangs on the chain, use the hook to hook the four hooks of the chain to the four lifting lugs of the slag tray; 1.1.3-After the slag worker confirms that the lifting lugs are hooked, notify the crane worker to lift and place the desulfurization slag tray to the position where the special hoist for transporting desulfurization slag can be hooked, and when placing, the slag tray needs to be adjusted, and after the chain is removed, the crane worker is responsible for lifting the special hoist with the main hook of the crane to transport the desulfurization slag tray to the corresponding hot steaming box.

[0023] 1.2, transporting desulfurization slag through the cross flat car The crane worker is responsible for driving the crane to hook the special hoist for transporting desulfurization slag, and then hoisting the desulfurization slag to the corresponding hot steaming box. The hot steaming box number is arranged by the preparation recovery team. If the special hoist cannot be directly used, the pre-treatment slag worker is responsible for hanging on the chain to assist the crane worker to hoist the desulfurization slag to the subway tray, remove the chain, and then use the special hoist to hoist the desulfurization slag into the steaming box.

[0024] Further, the specific operation of step 2 is as follows: 2.1, the preparation workshop recovery team operator receives the pre-treatment notification to arrange the hot steaming box, first confirms the hot steaming box position, confirms whether the hot steaming box is in use, and confirms whether the hot steaming box hydraulic station operation, dust removal fan, box body spray water and return water electric valve work is normal, and there is no any personnel staying on the hot steaming box body platform, then informs the operation room to open the hot steaming box turnover cover.

[0025] 2.2, the crane worker hoists the desulfurization slag tray into the hot steaming box, and accurately places the slag tray on the four supports in the hot steaming box. After confirming that it is placed well, the crane hook is disconnected from the slag tray, and the crane drives away from the hot steaming box area.

[0026] 2.3, the preparation workshop recovery team operator confirms that there is no personnel or foreign matter around the hot steaming box, and informs to close the turnover cover of the hot steaming box.

[0027] Further, the specific operation of step 3 is as follows: 3.1, the preparation workshop recovery team operator opens the electric valve of the dust removal pipeline on the digestion box, and the dust removal fan starts to exhaust.

[0028] 3.2, the preparation workshop recovery team operator opens the regulating valve and adjusts the opening to 30%. After the flowmeter shows stable, the opening is adjusted smaller until the flowmeter shows water flow of 6-7 m 3 / h, then count the water for half an hour, and close the opening for half an hour; After half an hour, open the water again, adjust the flow to 3-4 m 3 / h, and then control the water flow in this way, count the water for half an hour, and steam for half an hour.

[0029] 3.3, when starting hot fumigation, the fumigation box shows that the internal temperature is about 80-100℃, until about 4 hours, the temperature drops to about 30℃ (the amount of slag in the slag tray or the water fluctuation may vary, if the temperature in the fumigation box has dropped to below 40℃, the box can be opened to check the situation, whether it meets the slag turning conditions), the desulfurization slag is hot fumigated for 5 hours, the workshop recovery shift operator is prepared to open the cover to check the desulfurization slag, if it meets the slag turning conditions, it will notify the crane to lift it out, and notify the pretreatment foreman to send people to cooperate with the crane to lift the desulfurization slag to the desulfurization slag pool and overturn it, and the chain hanging work is implemented by the pretreatment, and the slag tray transportation and overturning are responsible by the crane. (The desulfurization slag is penetrated, there is no red slag, and no large steam is emitted, if it is not accurate, an oxygen blowing pipe can be inserted into the desulfurization slag to check the situation, if there is no red slag after inserting the desulfurization slag, it can be lifted out and turned over).

[0030] 3.4, because the initial design of the hot fumigation box is mainly used for steel slag hot fumigation, the flow meter control water range is a large range table compared with the desulfurization slag hot fumigation range, and the flow stability is poor, if the water flow is really large during hot fumigation or the amount of desulfurization slag entering the fumigation box is relatively large, the workshop can adjust the water time, and the water time is controlled to be 6-20min each time according to the actual situation, and the hot fumigation and water adding cycle is still controlled to be about 1 hour.

[0031] The desulfurization slag treated by the above hot fumigation method is subjected to slag-iron separation and recovery, and 10.52% of desulfurization slag iron can be recovered from the desulfurization slag, the slag-iron separation effect is good, and the slag-iron recovery rate is high.

[0032] The applicant processes the desulfurization slag according to the above hot fumigation method, and the environmental protection performance rating is B+, which meets the environmental protection requirement standard.

[0033] The above is only a preferred embodiment of the present application, it should be pointed out that the above preferred embodiment should not be regarded as a limitation of the present application, the protection scope of the present application should be limited by the scope defined by the claims. For ordinary skilled in the art, some improvements and refinements can be made without departing from the spirit and scope of the present application, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A method for treating desulfurization slag from molten iron, characterized in that: Includes the following steps: Step 1: Place the desulfurization slag skimmed from the surface of the desulfurized molten iron into a desulfurization slag pan; Step 2: Place the desulfurization slag tray from Step 1 into the hot quenching box; Step 3: The desulfurization residue is cooled by circulating water in the hot quenching box in a "water-quenching" manner. The number of cycles is at least three times, and the cycle time is 1 hour each time. The water-flushing time in each cycle is 6-30 minutes.

2. The method according to claim 1, characterized in that: In step 1, the amount of desulfurized slag added to the desulfurized slag pan accounts for 1 / 2 of the volume of the desulfurized slag pan.

3. The method according to claim 1, characterized in that: The cycle in step 3 is repeated four times.

4. The method according to claim 3, characterized in that: In step 3, the water volume for the first cycle is 6-7m. 3 Pump water at a flow rate of / h for 6-20 minutes, with the remaining three cycles each pumping 3-4m³ of water. 3 Pour water at a flow rate of / h for 6-20 minutes.

5. The method according to claim 3, characterized in that: In step 3, the water volume for the first cycle is 6-7m. 3 Pump water at a flow rate of / h for 30 minutes, and then perform three more cycles, each with a pumping volume of 3-4m³. 3 Pour water at a flow rate of / h for 30 minutes.

6. The method according to claim 1, characterized in that: In step 3, when the temperature displayed in the hot quenching box is below 30°C, the circulation is stopped, and the box is opened to check the condition of the desulfurization residue.

7. The method according to claim 6, characterized in that: The inspection of the desulfurization residue upon opening the box includes checking the steam emission and the red residue condition.

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