Energy-saving and emission-reducing production method of corrosion-resistant high-hardness grinding ball and grinding ball

Abstract

The invention relates to an energy-saving and emission-reducing production method of a corrosion-resistant high-hardness grinding ball and the grinding ball, and belongs to the technical field of metal materials and preparation thereof. According to the method, the components in the grinding ball are optimized by researching the heat treatment process of the grinding ball and combining the thermodynamic principle, and the graphene and the rare earth metal lanthanum are added, so that the corrosion resistance and the hardness of the grinding ball are effectively improved; the quenching process is further optimized, especially the quenching medium is optimized, the compactness of the core part of the grinding ball is improved, and the uniformity of the grinding ball is improved; compared with existing national standards and industrial standards, the comprehensive performance of the cast grinding ball is remarkably improved, energy conservation and emission reduction can be achieved, meanwhile, the production cost of the grinding ball is reduced, and the technology is simple and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials and preparation thereof, and in particular to a production method of strong and tough grinding balls for energy saving and emission reduction and the grinding balls. Background Art

[0002] Grinding balls are an important part of ball mills, playing the role of crushing and grinding materials. They are currently widely used in mining, power plants, chemical industry and other fields, and are in great demand. Grinding balls are consumables, and they may break at any time during the operation of the ball mill. The economic losses caused by grinding ball failure are huge every year, and the grinding ball needs to be shut down and replaced with new grinding balls after the grinding ball fails, which reduces the production efficiency of the enterprise. Therefore, the quality of grinding balls directly affects the production cost and production efficiency. Preparing a grinding ball with good comprehensive performance is an important means to improve the production efficiency of the ball mill and reduce costs.

[0003] Improving the hardness of the grinding balls is the most effective way to reduce wear. The grinding balls used in wet ball mills are also required to have a certain degree of corrosion resistance. Although a variety of grinding balls are currently available at home and abroad, they still have the defects of unsatisfactory hardness and toughness and poor corrosion resistance, which shortens their lifespan and limits their application.

[0004] Therefore, increasing the hardness of the grinding balls, ensuring a certain corrosion resistance of the grinding balls, and reducing the wear of the grinding balls are technical problems that technical personnel in this field need to solve urgently. Summary of the invention

[0005] In view of the technical problems of the above-mentioned grinding balls and their production process, such as low hardness and insufficient corrosion resistance, the present invention proposes a method for producing corrosion-resistant and high-hardness grinding balls for energy conservation and emission reduction and grinding balls. The method of the present invention optimizes the components in the grinding balls and adds graphene and rare earth metals, thereby reducing the adverse effects on the performance of the grinding balls, improving the corrosion resistance and hardness of the grinding balls, reducing the production cost of the grinding balls, and having a simple process and being green and environmentally friendly.

[0006] The present invention is achieved through the following technical solutions:

[0007] On the one hand, the present invention provides a corrosion-resistant and high-hardness grinding ball, the chemical composition of the grinding ball, measured by weight percentage, includes: C: 0.92-1.00, Si: 0.10-0.25, Mn: 0.90-1.00, P: ≤0.1, S: ≤0.1, graphene 0.10-0.25, Cr: 0.30-0.60, Ti: 0.008-0.020, B: 0.0005-0.0015, La: 0.14-0.22, and the rest is Fe and unavoidable impurities.

[0008] Graphene has stable six-membered ring structure of benzene, large specific surface area, high hardness and strength, etc., and the excellent mechanical properties of graphene itself are used to further improve the comprehensive performance of cast grinding balls. However, graphene itself is easy to agglomerate and difficult to combine with the matrix. The present invention introduces the rare earth element lanthanum and adjusts the proportion of the total formula of graphene materials to effectively reduce the agglomeration effect of graphene and enhance the bonding effect between the various component elements. The present invention optimizes the design of chemical composition, adds graphene and rare earth element lanthanum, redesigns the grinding ball composition, and improves the hardness and corrosion resistance of the grinding ball.

[0009] On the other hand, the present invention provides a method for producing corrosion-resistant high-hardness grinding balls for energy conservation and emission reduction, the method comprising the following steps:

[0010] (1) heating the scrap steel to 1550-1600°C to melt, then adding graphene, lanthanum (La), chromium (Cr), silicon (Si), and manganese (Mn) raw material powders and mixing them evenly to make the alloy reach the required chemical composition, and then casting and molding after melting to obtain a semi-finished grinding ball;

[0011] (2) The semi-finished grinding ball obtained in step (1) is reheated, quenched and tempered.

[0012] Preferably, the reheating comprises raising the temperature to 1350-1400° C. and keeping the temperature for 2-3 hours.

[0013] Preferably, the quenching temperature is 1100-1200°C.

[0014] Preferably, the quenching is performed with a 5-30% polyethylene glycol solution.

[0015] Preferably, the quenching time in step (2) is 3-10 minutes.

[0016] Preferably, the tempering temperature is 550°C to 600°C.

[0017] Preferably, the tempering time is 1 to 3 hours.

[0018] The present invention also provides a grinding ball produced by the above production method.

[0019] The present invention further optimizes the quenching process, especially the quenching medium, quenching temperature and quenching time, improves the density of the grinding ball core, and enhances the uniformity of the grinding ball, thereby effectively improving the comprehensive performance of the cast grinding ball and obtaining a corrosion-resistant and high-hardness grinding ball.

[0020] Beneficial effects of the present invention:

[0021] The present invention optimizes the components in the grinding balls, adds graphene and rare earth metal lanthanum, and effectively improves the corrosion resistance and hardness of the grinding balls; and further optimizes the quenching process, especially optimizes the quenching medium, improves the density of the core of the grinding balls, and improves the uniformity of the grinding balls; compared with the current national standards and industry standards, the comprehensive performance of the cast grinding balls is significantly improved. After testing, the surface hardness of the grinding balls of the present invention is ≥65HRC, the hardness difference between the core and the surface is ≤3HRC, the impact toughness is ≥35J / cm2, the ball consumption is ≤250g / t of ore, the crushing rate is less than 0.2%; the corrosion rate is ≤0.76g / m2·h; the crack depth (mm) after 5000 thermal cycles is ≤1mm; it can achieve energy saving and emission reduction, while reducing the production cost of the grinding balls, the process is simple, and it is green and environmentally friendly. DETAILED DESCRIPTION

[0022] For ease of understanding, the present application will be described more fully below, and preferred embodiments of the present application are given. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein.

[0023] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products available on the market.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0025] Example 1

[0026] A corrosion-resistant high-hardness grinding ball, the chemical composition of the grinding ball, measured by weight percentage, includes: C: 0.92, Si: 0.10, Mn: 0.90, P: ≤0.1, S: ≤0.1, graphene 0.10, Cr: 0.30, Ti: 0.008, B: 0.0005, La: 0.14, and the rest is Fe and unavoidable impurities.

[0027] The production process is as follows:

[0028] (1) According to the above formula, the scrap steel is first melted in a medium frequency induction furnace, heated to 1550-1600℃, and graphene, lanthanum (La), chromium (Cr), silicon (Si), and manganese (Mn) raw material powders are added and mixed evenly to make the alloy reach the required chemical composition. The chemical element content is determined by direct reading spectrometer, and after qualified smelting, casting is performed to obtain a semi-finished grinding ball; (2) The obtained semi-finished grinding ball is reheated to 1350-1400℃ and kept warm for 2.5 hours; when the casting grinding ball temperature is 1100-1200℃, it is immersed in a 10% polyethylene glycol solution for quenching treatment, and the quenching time is 3-10 minutes; the quenched grinding ball is loaded into a tempering furnace, heated to 550℃~600℃, tempered for 2h, and taken out of the furnace to obtain the finished product.

[0029] Example 2

[0030] A corrosion-resistant high-hardness grinding ball, the chemical composition of the grinding ball, measured by weight percentage, includes: C: 1.00, Si: 0.25, Mn: 1.00, P: ≤0.1, S: ≤0.1, graphene 0.25, Cr: 0.60, Ti: 0.020, B: 0.0015, La: 0.22, and the rest is Fe and unavoidable impurities.

[0031] The manufacturing process is as follows:

[0032] (1) According to the above formula, the scrap steel is first melted in a medium frequency induction furnace, heated to 1550-1600℃, and graphene, lanthanum (La), chromium (Cr), silicon (Si), and manganese (Mn) raw material powders are added and mixed evenly to make the alloy reach the required chemical composition. The chemical element content is determined by direct reading spectrometer, and after qualified smelting, casting is performed to obtain a semi-finished grinding ball; (2) The obtained semi-finished grinding ball is reheated to 1350-1400℃ and kept warm for 2.5 hours; when the casting grinding ball temperature is 1100-1200℃, it is immersed in a 5% polyethylene glycol solution for quenching treatment, and the quenching time is 3-10 minutes; the quenched grinding ball is loaded into a tempering furnace, heated to 550℃~600℃, tempered for 2h, and taken out of the furnace to obtain the finished product.

[0033] Example 3

[0034] A corrosion-resistant high-hardness grinding ball, the chemical composition of the grinding ball, measured by weight percentage, includes: C: 0.95, Si: 0.2, Mn: 0.95, P: ≤0.1, S: ≤0.1, graphene 0.2, Cr: 0.5, Ti: 0.01, B: 0.001, La: 0.2, and the rest is Fe and unavoidable impurities.

[0035] The manufacturing process is as follows:

[0036] (1) According to the above formula, the scrap steel is first melted in a medium frequency induction furnace, heated to 1550-1600℃, and graphene, lanthanum (La), chromium (Cr), silicon (Si), and manganese (Mn) raw material powders are added and mixed evenly to make the alloy reach the required chemical composition. The chemical element content is determined by direct reading spectrometer, and after qualified smelting, casting is performed to obtain a semi-finished grinding ball; (2) The obtained semi-finished grinding ball is reheated to 1350-1400℃ and kept warm for 2.5 hours; when the casting grinding ball temperature is 1100-1200℃, it is immersed in a 30% polyethylene glycol solution for quenching treatment, and the quenching time is 3-10 minutes; the quenched grinding ball is loaded into a tempering furnace, heated to 550℃~600℃, tempered for 2h, and taken out of the furnace to obtain the finished product.

[0037] Comparative Example 1

[0038] On the basis of Example 1, no graphene is added, and the rest is the same as Example 1.

[0039] Comparative Example 2

[0040] On the basis of Example 1, no metallic lanthanum was added, and the rest was the same as Example 1.

[0041] Comparative Example 3

[0042] On the basis of Example 1, graphene and metallic lanthanum were not added, and the rest was the same as Example 1.

[0043] Comparative Example 4

[0044] On the basis of Example 1, the quenching medium is changed to immersion in water, and the rest is the same as Example 1.

[0045] Example 4

[0046] The performance of the grinding balls prepared in Examples 1-3 and Comparative Examples 1-4 was tested and compared, wherein: hardness test: tested on a HR-150A Rockwell hardness tester; impact toughness test: prepared unnotched impact specimens according to the standard of GB229-63, and used a JB30A pendulum impact tester for impact testing; copper ore was wet ground with grinding balls having a diameter of 80 mm, the wet grinding operation time was 800 h, and the crushing rate and ball consumption were calculated; the high-temperature thermal cracking resistance was represented by the crack depth of the thermal cycle, and the crack depth was detected after 5000 thermal cycles between 25-400°C according to the method of GB / T 6398-2017.

[0047] The test shows that the grinding balls of Examples 1-3 of the present invention have a surface hardness ≥65HRC, a center-surface hardness difference ≤3HRC, an impact toughness ≥35J / cm2, a ball consumption ≤250g / t ore, a crushing rate less than 0.2%, a corrosion rate ≤0.76g / m2·h, and a crack depth (mm) ≤1mm after 5000 thermal cycles.

[0048] Compared with the embodiments, the difference is that the surface hardness of the grinding balls of Comparative Examples 1-3 in the present invention is between 50-55HRC; the surface hardness of the grinding balls of Comparative Example 4 is ≥65HRC; the crack depth (mm) of the grinding balls prepared in Comparative Example 4 is ≥10mm after 5000 thermal cycles.

[0049] The test shows that the grinding balls prepared in Examples 1-3 of the present invention have better hardness, corrosion resistance and high temperature thermal cracking resistance. The addition of graphene and metal lanthanum can synergistically increase the hardness of the grinding balls, while the different quenching media in the quenching process will affect the density and uniformity of the core of the grinding balls. The grinding balls of the present invention have very small crack depth after 5000 thermal cycles, are not easy to crack, and have better comprehensive performance. Comparative Examples 1-3 and Comparative Example 4 are both comparative experiments of single replacement of the present invention, and their hardness is far different from that of Examples 1-3 of the present invention. Comparative Example 4 is far inferior to Examples 1-3 in terms of high temperature thermal cracking resistance, indicating that the grinding balls prepared using Examples 1-3 of the present invention not only have higher hardness, better corrosion resistance and high temperature thermal cracking resistance.

[0050] The above-mentioned embodiments only express the implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for producing corrosion-resistant and high-hardness grinding balls for energy conservation and emission reduction, characterized in that: The steps include: (1) heating the scrap steel to 1550-1600°C to melt, then adding graphene, lanthanum (La), chromium (Cr), silicon (Si), and manganese (Mn) raw material powders and mixing them evenly to make the alloy reach the required chemical composition, and then casting and molding after melting to obtain a semi-finished grinding ball; (2) reheating the semi-finished grinding balls obtained in step (1) and subjecting them to quenching and tempering; The chemical composition of the grinding ball, measured by weight percentage, includes: C: 0.92-1.00, Si: 0.10-0.25, Mn: 0.90-1.00, P: ≤0.1, S: ≤0.1, graphene 0.10-0.25, Cr: 0.30-0.60, Ti: 0.008-0.020, B: 0.0005-0.0015, La: 0.14-0.22, and the rest is Fe and unavoidable impurities.

2. The production method according to claim 1, characterized in that: The reheating includes raising the temperature to 1350-1400° C. and keeping the temperature for 2-3 hours.

3. The production method according to claim 1, characterized in that: The quenching temperature is 1100-1200°C.

4. The production method according to claim 1, characterized in that: The quenching is performed with a 5-30% polyethylene glycol solution.

5. The production method according to claim 1, characterized in that: Step (2) quenching time is 3-10 minutes.

6. The production method according to claim 1, characterized in that: The tempering temperature is 550°C to 600°C.

7. The grinding ball produced according to the production method of claim 1.