A method of splat quenching

Abstract

This invention discloses a method for maintaining furnace lining by slag splashing. The steps are as follows: After steel is tapped from the converter, half of the slag is poured out and hot-quenched. After hot-quenching, the slag is magnetically separated and processed, and the hot-quenched slag is transported back to the converter for loading. Simultaneously, after steel is tapped from the converter and half of the slag is poured out, the furnace is uprighted, and nitrogen is blown into the oxygen lance. After the oxygen lance is lowered to 2m from the furnace bottom, 500kg of hot-quenched slag is added from the high-level hopper. After adding the slag, the oxygen lance is lowered sequentially to 1.8m, 1.6m, and 1.45m from the furnace bottom, with 500kg of hot-quenched slag added after each lowering. After blowing nitrogen at 1.45m for 40s, the oxygen lance is raised to 1.8m, and another 500kg of hot-quenched slag is added. After continuing to blow nitrogen for 40s, the oxygen lance is lowered to 1.45m, and after continuing to blow nitrogen for 80s, the lance is raised, and 1000kg of hot-quenched slag is added at the same time. This method can quickly cool the slag, reduce nitrogen consumption, and thus reduce production costs.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, and specifically relates to a method for slag splashing maintenance of furnace lining. Background Technology

[0002] Slag splashing protection technology utilizes steelmaking end-point slag with MgO content reaching saturation or supersaturation. Through high-pressure nitrogen splashing, the slag is cooled and solidified onto the furnace lining surface to form a high-melting-point slag layer, which adheres well to the furnace lining and protects the furnace lining bricks.

[0003] However, in actual operation, in order to achieve good dephosphorization in the converter, a large amount of final slag is left. This results in excessively long nitrogen blowing time during slag cooling, excessive nitrogen consumption, and the slag is not easy to cool and cannot adhere to the furnace lining surface, causing frequent furnace lining alarms, frequent accidents, and affecting production efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for slag splashing maintenance of furnace linings, which can rapidly cool the slag, reduce nitrogen consumption, and thus lower production costs.

[0005] This invention is achieved through the following technical solution:

[0006] A method for maintaining furnace lining by slag splashing includes the following steps:

[0007] Step 1) After the converter finishes tapping steel, half of the slag is poured out; the poured slag is transported through the slag pot to the slag-quenching tank for hot quenching;

[0008] Step 2) The hot-quenched slag is first magnetically separated to remove large pieces of slag steel, and then further processed to reduce the particle size of the slag; the processed hot-quenched slag is screened and then transported back to the converter for loading.

[0009] Step 3) After the converter has finished tapping steel and half of the slag has been poured out in Step 1), straighten the furnace, blow inert gas into the oxygen lance, and lower the oxygen lance to 2m from the furnace bottom. Then, add 500kg of hot slag from the high-level hopper. After adding the slag, lower the oxygen lance to 1.8m from the furnace bottom, and add another 500kg of hot slag from the high-level hopper. After adding the slag, lower the oxygen lance to 1.6m from the furnace bottom, and add another 500kg of hot slag from the high-level hopper. After adding the slag, lower the oxygen lance to... Lower the oxygen lance to 1.45m from the furnace bottom, then add 500kg of hot slag from the high-level hopper; after blowing inert gas into the oxygen lance for 40s at a distance of 1.45m from the furnace bottom, raise it to 1.8m from the furnace bottom, and add another 500kg of hot slag from the high-level hopper; after continuing to blow inert gas for 40s, lower the oxygen lance to 1.45m from the furnace bottom, continue to blow inert gas for 80s, and then raise the lance, adding 1000kg of hot slag at the same time.

[0010] Preferably, the particle size of the processed hot-cooked residue in step 2) is ≤1cm.

[0011] Preferably, the inert gas in step 3) is nitrogen or argon.

[0012] Preferably, the flow rate of the inert gas blown in step 3) is 29,500–30,500 m³ / h. 3 / h.

[0013] Preferably, the total time for blowing inert gas in step 3) is 160-180 seconds.

[0014] The beneficial effects of this invention are as follows:

[0015] The method for maintaining furnace lining by splashing slag in this invention controls the amount of hot slag in the furnace, cools the hot slag using hot slag curing, and accelerates the slag cooling rate by stirring with high-pressure nitrogen, thereby reducing slag splashing time and nitrogen consumption. Simultaneously, it increases the amount of slag adhering to the furnace lining surface, reducing the erosion of the furnace lining bricks. This invention is suitable for large-scale industrial production, improving production efficiency and reducing production costs. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments.

[0017] Example 1

[0018] A method for maintaining furnace lining by slag splashing, the specific steps of which are as follows:

[0019] (1) After the converter finishes tapping steel, half of the slag is poured out.

[0020] (2) The slag poured out is transported through the slag tank to the slag braising pool for hot braising.

[0021] (3) The hot-cooked residue is transported to a new materials company for processing after magnetic separation.

[0022] The hot-cooked slag contains steel slag, which is large in size and can be used as a substitute for scrap steel after magnetic separation. However, the slag after magnetic separation still contains large steel slag particles, which need to be transported to a new materials company for further processing to reduce their particle size, ultimately processing the slag to the point that the particles cannot exceed 1 cm.

[0023] (4) The processed hot-cured slag (particle size ≤ 1cm) is screened and then transported back to the converter for loading into the upper silo (high-level silo). The main components of the hot-cured slag are shown in Table 1 below:

[0024] Table 1. Main components (wt%) of hot-cooked residue

[0025]

[0026]

[0027] Table 1 lists the composition of hot slag from a total of 19 heats. It can be seen that the proportion of CaO and MgO in the hot slag is quite high. If it is directly treated as waste, it will cause huge waste. The present invention mainly utilizes CaO and MgO in the hot slag for slag splashing and furnace protection.

[0028] (5) After the converter has finished tapping steel and half of the slag in step (1), the furnace is uprighted, nitrogen is blown in with the oxygen lance, and the oxygen lance is lowered to a distance of 2m from the furnace bottom (this is the distance between the oxygen lance head and the furnace bottom, the same below). Then, 500kg of hot slag is added from the high-level hopper. After adding the slag, the oxygen lance is lowered to a distance of 1.8m from the furnace bottom, and another 500kg of hot slag is added from the high-level hopper. After adding the slag, the oxygen lance is lowered to a distance of 1.6m from the furnace bottom, and another 500kg of hot slag is added from the high-level hopper. After lowering the oxygen lance to 1.45m from the furnace bottom, add 500kg of hot slag from the high-level hopper. After blowing nitrogen into the oxygen lance for 40s at a distance of 1.45m from the furnace bottom, raise it to 1.8m from the furnace bottom and add another 500kg of hot slag from the high-level hopper. Continue blowing nitrogen for another 40s, then lower the oxygen lance to 1.45m from the furnace bottom and continue blowing nitrogen for another 80s before raising the lance (total nitrogen blowing time is 160-180s). At the same time as raising the lance, add 1000kg of hot slag.

[0029] The nitrogen gas used in the above steps can be replaced by argon gas. However, for cost reasons, nitrogen gas is used in this embodiment, and the flow rate of the nitrogen gas is set to 29,500–30,500 m³ / h. 3 / h.

[0030] Compared to the traditional slag splashing furnace protection method, this embodiment reduces the slag splashing time by approximately 60 seconds and nitrogen consumption by 500 m³. 3 This effectively improved production efficiency and reduced production costs.

[0031] The embodiments described above are only some, not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. The scope of protection of the present invention is determined by the scope claimed in the claims. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method of sldag maintenance of a furnace lining, characterized in that, Includes the following steps: Step 1) After the converter finishes tapping steel, half of the slag is poured out; the poured slag is transported through the slag pot to the slag-quenching tank for hot quenching; Step 2) The hot-quenched slag is first magnetically separated to remove large pieces of slag steel, and then further processed to reduce the particle size of the slag; the processed hot-quenched slag is screened and then transported back to the converter for loading. Step 3) After the converter has finished tapping steel and half of the slag has been poured out in Step 1), the furnace is uprighted. Inert gas or nitrogen is blown into the oxygen lance. After the oxygen lance is lowered to 2 m from the furnace bottom, 500 kg of hot slag is added from the high-level hopper. After adding the slag, the oxygen lance is lowered to 1.8 m from the furnace bottom, and another 500 kg of hot slag is added from the high-level hopper. After adding the slag, the oxygen lance is lowered to 1.6 m from the furnace bottom, and another 500 kg of hot slag is added from the high-level hopper. After adding the slag, the oxygen lance is lowered to 1.45 m from the furnace bottom, and another 500 kg of hot slag is added from the high-level hopper. Inert gas is blown into the oxygen lance at 1.45 m from the furnace bottom for 40 seconds, then the lance is raised to 1.8 m from the furnace bottom, and another 500 kg of hot slag is added from the high-level hopper. Inert gas is blown into the lance again for 40 seconds, then the oxygen lance is lowered to 1.45 m from the furnace bottom, and inert gas is blown into the lance again for 80 seconds. After lifting the gun, add 1000 kg of hot simmering residue at the same time.

2. A method of resurfacing a furnace lining according to claim 1 wherein, Step 2) The particle size of the processed hot-cooked residue is ≤1 cm.

3. A method of resurfacing a furnace lining according to claim 1 wherein, Step 3) The inert gas is argon.

4. A method of resurfacing a furnace lining according to claim 1 wherein, Step 3) the flow rate of the inert gas is 29500 to 30500 m 3 / h.

5. A method of resurfacing a furnace lining according to claim 1 wherein, Step 3) The total time for blowing in the inert gas is 160~180 s.

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