High-carbon ferromanganese iron powder remelting process

Abstract

The application discloses a high-carbon ferromanganese iron powder remelting process, which comprises the following steps: step one, pickling: high-carbon ferromanganese iron powder is subjected to pickling under the action of a pickling solution, so that a surface oxide layer is removed, and deoxidized ferromanganese iron powder is obtained; and step two, ultrasonic cleaning: the deoxidized ferromanganese iron powder obtained in step one is added into an ultrasonic cleaning machine for cleaning, so that surface stains and grease are removed. After preheating and degassing, nitrogen and oxygen of the ferromanganese sintered block are detected, and ingredients are prepared according to the nitrogen content, so that the ingredient amount is more reasonable, and the quality of the high-carbon ferromanganese alloy is improved. Moreover, the deoxidized skin of the high-carbon ferromanganese iron powder is removed outside the furnace, so that the deoxidized skin does not need to be removed by using a lossy reagent covering agent in the furnace, the alloy is less damaged, and the ferromanganese burning loss is reduced. As a result, the formed manganese oxide slag is less, the quality of the high-carbon ferromanganese finished product is greatly improved based on the above two points, the chemical composition of the high-carbon ferromanganese finished product is uniform, and the prepared high-carbon ferromanganese alloy has higher hardness and toughness.

Description

Technical Field

[0001] This invention relates to the field of ferromanganese remelting technology, specifically a high-carbon ferromanganese powder remelting process. Background Technology

[0002] Ferromanganese alloys are Mn-Fe-C ternary alloys containing small amounts of impurities such as P, S, and Si. Based on carbon content, they can be classified into low-carbon ferromanganese, medium-carbon ferromanganese, and high-carbon ferromanganese. High-carbon ferromanganese has a melting point of 1220–1270℃. High-carbon ferromanganese alloys are mainly used in steelmaking as deoxidizers and alloying additives. During the smelting and preparation of high-carbon ferromanganese, the size of the alloy blocks is controlled during the alloying operation of molten steel to reduce burn-off and ensure uniform steel composition. Therefore, large ferromanganese alloy blocks need to be crushed before leaving the factory. The crushing process generates a large amount of powder as reclaimed material, which is high-carbon ferromanganese powder. The price of high-carbon ferromanganese powder is much lower than that of block alloys. Using it as raw material to remelt and reprocess high-carbon ferromanganese can reduce the production cost. However, the high-carbon ferromanganese products prepared using high-carbon ferromanganese powder as reclaimed material currently have the following drawbacks:

[0003] Currently, the quality of high-carbon ferromanganese products prepared using high-carbon ferromanganese powder as recycled material is relatively low, mainly due to poor hardness and toughness. There are two main reasons for this: First, the amount of high-carbon ferromanganese powder added during smelting is not precisely calculated, often using a 30-50% recycling ratio without considering the nitrogen content in the powder, resulting in poor product quality. Second, descaling of the recycled high-carbon ferromanganese powder is often carried out in the furnace using a covering agent. This agent causes loss of the ferromanganese, resulting in significant ferromanganese burn-off and a large amount of manganese oxide slag, leading to large grain sizes in the alloy after forming. These two factors combined result in low toughness and hardness in the remelted ferromanganese alloy product.

[0004] Therefore, we propose a high-carbon ferromanganese iron powder remelting process to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a high-carbon ferromanganese iron powder remelting process to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a remelting process for high-carbon ferromanganese iron powder, comprising the following steps:

[0007] Step 1: Pickling: High-carbon ferromanganese powder is pickled in pickling solution to remove the surface oxide layer and obtain deoxidized ferromanganese powder.

[0008] Step 2: Ultrasonic cleaning: Add the deoxidized manganese iron powder obtained in Step 1 into an ultrasonic cleaner to clean and remove surface stains and grease, and obtain impurity-free manganese iron powder.

[0009] Step 3: Cold pressing into cakes: The manganese iron powder obtained in step 2 is cold pressed into cakes to obtain manganese iron powder cakes;

[0010] Step 4: Preheating and degassing: Add the ferromanganese powder cake obtained in Step 3 into the crucible in the smelting furnace, evacuate the smelting furnace to a pressure of -0.05MPa to -0.1MPa, then introduce inert gas and preheat and degas at a temperature of 200 to 600℃. Then, under a protective atmosphere with a pressure of 0.01MPa to 0.2MPa, raise the temperature to 700 to 1200℃ and sinter for 1 to 4 hours. After that, cool down to obtain ferromanganese sintered blocks.

[0011] Step 5: Nitrogen and oxygen detection: The nitrogen and oxygen content of the manganese-iron sintered block obtained in Step 4 is detected.

[0012] Step Six: Smelting: Add the ingredients to the crucible in the smelting furnace to form a mixture. The proportion of ingredients is adjusted according to the nitrogen and oxygen content. The weight ratio of ingredients to ferromanganese sinter is as follows: 30-70 parts ingredients, 30-70 parts ferromanganese sinter. The higher the nitrogen content, the lower the weight ratio of ferromanganese sinter. After melting in the furnace, high-carbon ferromanganese product is obtained.

[0013] Preferably, the pickling solution in step one is a mixture of hydrochloric acid, phosphoric acid, oxalic acid, sodium dodecyl sulfate, OP-10, and water, and the weight proportions of the hydrochloric acid, phosphoric acid, oxalic acid, sodium dodecyl sulfate, OP-10, and water are as follows: 10 parts hydrochloric acid, 8 parts phosphoric acid, 4 parts oxalic acid, 2 parts sodium dodecyl sulfate, 1 part OP-10, and 75 parts water.

[0014] Preferably, the inert gas in step two is a mixture of argon and hydrogen, with the volume ratio of argon to hydrogen as follows: 80-95% argon and 5-20% hydrogen.

[0015] Preferably, the in-furnace infusion process in step six is ​​as follows: the power of the smelting furnace is adjusted to 95-100kW, the temperature of the smelting furnace is raised to 1220-1270℃ until the furnace charge is completely melted, and the furnace is kept at this temperature for 10-15 minutes. Then the temperature of the smelting furnace is raised to 1580-1620℃, and electromagnetic stirring is used to allow low-melting-point impurities and low-density inclusions in the mixture to float to the surface. Some inclusions are adhered to the crucible wall to purify the molten steel. Then deoxidizer is added for deoxidation. After cooling in the furnace, the molten steel is poured out to obtain the high-carbon ferromanganese product.

[0016] Preferably, the deoxidizer is a silicon-strontium-barium alloy, wherein the weight proportions of each element in the silicon-strontium-barium alloy are as follows: silicon 55-66 parts, calcium 15-27 parts, and barium 12-26 parts.

[0017] Preferably, the crucible inside the smelting furnace is a corundum crucible.

[0018] Preferably, the ingredients in step six are a mixture of pig iron and scrap steel, and the weight ratio of pig iron to scrap steel is 55-65 parts pig iron and 35-45 parts scrap steel.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] This invention performs nitrogen and oxygen testing on the ferromanganese sintered blocks after preheating and degassing, and adjusts the batching based on the nitrogen content, resulting in a more reasonable batching amount and thus improving the quality of the high-carbon ferromanganese alloy. Furthermore, the descaling of the high-carbon ferromanganese powder is carried out outside the furnace, eliminating the need for destructive covering agents during furnace smelting, thus minimizing damage to the alloy and reducing ferromanganese burn-off. This results in less manganese oxide slag. Based on these two points, the quality of the finished high-carbon ferromanganese product is greatly improved, resulting in a more uniform chemical composition and higher hardness and toughness in the prepared high-manganese alloy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the preparation process of the present invention; Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1:

[0024] Please see Figure 1 This invention provides a technical solution: a remelting process for high-carbon ferromanganese iron powder, comprising the following steps:

[0025] Step 1: Pickling: High-carbon ferromanganese powder is pickled in pickling solution to remove the surface oxide layer, resulting in deoxidized ferromanganese powder. By removing the oxide layer on the surface of high-carbon ferromanganese powder through pickling, there is no need to use a covering agent during smelting, which reduces the damage to the alloy, reduces the loss of ferromanganese, and results in less manganese oxide slag.

[0026] Step 2: Ultrasonic cleaning: Add the deoxidized manganese iron powder obtained in Step 1 into an ultrasonic cleaner to clean and remove surface stains and grease, and obtain impurity-free manganese iron powder.

[0027] Step 3: Cold pressing into cakes: The manganese iron powder obtained in step 2 is cold pressed into cakes to obtain manganese iron powder cakes. This step facilitates the transportation of manganese iron powder cakes, and compared with the transportation of manganese iron powder, there will be no loosening or other phenomena.

[0028] Step 4: Preheating and Degassing: Add the ferromanganese powder cake obtained in Step 3 into the crucible in the smelting furnace. Evacuate the smelting furnace to a pressure of -0.05MPa to -0.1MPa. Then, introduce inert gas and preheat and degas at a temperature of 200 to 600℃. Then, under a protective atmosphere with a pressure of 0.01MPa to 0.2MPa, raise the temperature to 700 to 1200℃ and sinter for 1 to 4 hours. After cooling, sintered ferromanganese blocks are obtained. Preheating and degassing facilitates the detection of nitrogen and oxygen content.

[0029] Step 5: Nitrogen and oxygen detection: The nitrogen and oxygen content of the manganese-iron sintered block obtained in Step 4 is detected.

[0030] Step Six: Melting: Add the ingredients to the crucible in the melting furnace to form a mixture. The proportion of ingredients is adjusted according to the nitrogen and oxygen content. The weight ratio of ingredients to ferromanganese sinter is as follows: 30-70 parts ingredients, 30-70 parts ferromanganese sinter. The higher the nitrogen content, the lower the weight ratio of ferromanganese sinter. After melting in the furnace, high-carbon ferromanganese is obtained. The proportion of ingredients is adjusted according to the nitrogen content, and the return ratio of ferromanganese sinter is adjusted. The high-carbon ferromanganese has a uniform chemical composition, and the high-manganese ferroalloy prepared in this way has higher hardness and toughness.

[0031] Example 2:

[0032] The second embodiment of the present invention is based on the previous embodiment. In step one, the pickling solution is a mixture of hydrochloric acid, phosphoric acid, oxalic acid, sodium dodecyl sulfate, OP-10, and water. The weight ratios of hydrochloric acid, phosphoric acid, oxalic acid, sodium dodecyl sulfate, OP-10, and water are as follows: 10 parts hydrochloric acid, 8 parts phosphoric acid, 4 parts oxalic acid, 2 parts sodium dodecyl sulfate, 1 part OP-10, and 75 parts water.

[0033] In step two, the inert gas is a mixture of argon and hydrogen, with the following volume ratios: argon 80-95% and hydrogen 5-20%.

[0034] The in-furnace infusion process in step six is ​​as follows: Adjust the power of the smelting furnace to 95-100kW, raise the temperature of the smelting furnace to 1220-1270℃ until the furnace charge is completely melted, keep it at the temperature for 10-15 minutes, then raise the temperature of the smelting furnace to 1580-1620℃, use electromagnetic stirring to allow the low melting point impurities and low density inclusions in the mixture to float fully, and adhere some inclusions to the crucible wall to purify the molten steel. Then add deoxidizer for deoxidation, cool with the furnace and pour out to cool, to obtain the high carbon ferromanganese product.

[0035] The deoxidizer is a silicon-strontium-barium alloy, and the weight proportions of each element in the silicon-strontium-barium alloy are as follows: silicon 55-66 parts, calcium 15-27 parts, and barium 12-26 parts.

[0036] The crucible inside the smelting furnace is made of corundum. Corundum crucibles are hard, resistant to melting, resistant to rapid heating and cooling, and resistant to chemical corrosion, making them more suitable for smelting manganese and iron.

[0037] In step six, the ingredients are a mixture of pig iron and scrap steel, with the weight ratio of pig iron to scrap steel being 55-65 parts and scrap steel 35-45 parts.

[0038] Example 3:

[0039] Please see Figure 1 This is the third embodiment of the present invention, based on the above two embodiments. The preparation method of the present invention is as follows: Step 1: Pickling: High-carbon ferromanganese powder is pickled in pickling solution to remove the surface oxide layer, resulting in deoxidized ferromanganese powder; Step 2: Ultrasonic cleaning: The deoxidized ferromanganese powder obtained in Step 1 is added to an ultrasonic cleaner to remove surface stains and grease, resulting in purified ferromanganese powder; Step 3: Cold pressing into cakes: The purified ferromanganese powder obtained in Step 2 is cold-pressed into cakes, resulting in ferromanganese powder cakes; Step 4: Preheating and degassing: The ferromanganese powder cakes obtained in Step 3 are added to a crucible in a smelting furnace, and the smelting furnace is evacuated to a pressure of -0.05MPa to -0.1MPa, and then inert gas is introduced. The gas is preheated and degassed at a temperature of 200–600℃, and then sintered at 700–1200℃ for 1–4 hours under a protective atmosphere of 0.01 MPa–0.2 MPa pressure, followed by cooling to obtain ferromanganese sintered blocks; Step 5: Nitrogen and oxygen detection: The ferromanganese sintered blocks obtained in Step 4 are subjected to nitrogen and oxygen detection to determine the nitrogen and oxygen content; Step 6: Melting: The ingredients are added to the crucible in the melting furnace to form a mixture. The proportion of ingredients is added according to the nitrogen and oxygen content. The weight ratio of ingredients to ferromanganese sintered blocks is as follows: 30–70 parts ingredients, 30–70 parts ferromanganese sintered blocks. The higher the nitrogen content, the lower the weight ratio of ferromanganese sintered blocks. After melting in the furnace, high-carbon ferromanganese finished products are obtained. This invention performs nitrogen and oxygen testing on the ferromanganese sintered blocks after preheating and degassing, and adjusts the batching based on the nitrogen content, resulting in a more reasonable batching amount and thus improving the quality of the high-carbon ferromanganese alloy. Furthermore, the descaling of the high-carbon ferromanganese powder is carried out outside the furnace, eliminating the need for destructive covering agents during furnace smelting, thus minimizing damage to the alloy and reducing ferromanganese burn-off. This results in less manganese oxide slag. Based on these two points, the quality of the finished high-carbon ferromanganese product is greatly improved, resulting in a more uniform chemical composition and higher hardness and toughness in the prepared high-manganese alloy.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-carbon ferromanganese iron powder remelting process, characterized in that The method comprises the following steps: Step one pickling: high carbon ferromanganese powder is pickled in a pickling solution to remove the surface oxide layer and obtain deoxidized ferromanganese powder; Step two ultrasonic cleaning: the deoxidized ferromanganese powder obtained in step one is added into an ultrasonic cleaning machine to remove surface stains and grease and obtain impurity-removed ferromanganese powder; Step three cold pressing into a cake: the impurity-removed ferromanganese powder obtained in step two is cold pressed into a cake to obtain a ferromanganese powder cake; Step four preheating and degassing: the ferromanganese powder cake obtained in step three is added into a crucible of a smelting furnace, the smelting furnace is vacuumized to have a pressure of -0.05 MPa to -0.1 MPa, then inert gas is introduced, preheating and degassing are performed at a temperature of 200-600 DEG C, then the temperature is raised to 700-1200 DEG C under a protective atmosphere with a pressure of 0.01 MPa to 0.2 MPa, sintering is performed for 1-4 hours, then cooling is performed after temperature reduction, and a ferromanganese sintered block is obtained; Step five nitrogen and oxygen detection: nitrogen and oxygen detection is performed on the ferromanganese sintered block obtained in step four to detect the nitrogen and oxygen content; Step six smelting: ingredients are added into the crucible of the smelting furnace to form a mixture, the ingredient proportion is added according to the nitrogen and oxygen content, and the weight proportion ratio of the ingredients to the ferromanganese sintered block is as follows: 30-70 parts of ingredients and 30-70 parts of ferromanganese sintered block, the higher the nitrogen content, the lower the weight proportion of the ferromanganese sintered block, and high carbon ferromanganese products are obtained after smelting in the furnace, wherein the ingredients are a mixture of pig iron and scrap steel.

2. The high-carbon ferromanganese ferroalloy remelting process according to claim 1, characterized in that: The pickling solution in step one is a mixture of hydrochloric acid, phosphoric acid, oxalic acid, sodium dodecyl sulfate, OP-10 and water, and the weight proportion ratio of the hydrochloric acid, phosphoric acid, oxalic acid, sodium dodecyl sulfate, OP-10 and water is as follows: 10 parts of hydrochloric acid, 8 parts of phosphoric acid, 4 parts of oxalic acid, 2 parts of sodium dodecyl sulfate, 1 part of OP-10 and 75 parts of water.

3. The high-carbon ferromanganese ferroalloy remelting process of claim 1, wherein: The inert gas in step two is a mixture of argon and hydrogen, and the volume ratio of the argon to hydrogen is as follows: 80-95% of argon and 5-20% of hydrogen.

4. The high-carbon ferromanganese ferroalloy remelting process of claim 1, wherein: In step six, the smelting in the furnace is performed as follows: the power of the smelting furnace is adjusted to 95-100 kW, the temperature of the smelting furnace is raised to 1220-1270 DEG C until the furnace charge is completely melted, the smelting furnace is kept at the temperature for 10-15 min, then the smelting furnace is raised to a temperature of 1580-1620 DEG C, electromagnetic stirring is used to make the low-melting-point impurity elements and low-density inclusions in the mixture sufficiently float up, and part of the inclusions adhere to the crucible wall to purify the molten steel, then a deoxidizer is added to deoxidize, the smelting furnace is cooled down with the furnace, and the cooled high carbon ferromanganese products are poured out.

5. The high-carbon ferromanganese ferroalloy remelting process of claim 4, wherein: The deoxidizer is a silicon-strontium-barium alloy, and the weight proportion ratio of the elements in the silicon-strontium-barium alloy is as follows: 55-66 parts of silicon, 15-27 parts of calcium and 12-26 parts of barium.

6. The high-carbon ferromanganese ferroalloy remelting process of claim 1, wherein: The crucible in the smelting furnace is a corundum crucible.

7. The high-carbon ferromanganese ferroalloy remelting process of claim 1, wherein: The weight proportion ratio of the pig iron to scrap steel is as follows: 55-65 parts of pig iron and 35-45 parts of scrap steel.

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