High-hardness and high-volume-density brown aluminum oxide process

Abstract

The invention provides a high-hardness and high-volume-density brown aluminum oxide process which comprises the following steps: step 1, raw material pretreatment for stably feeding bauxite into a shaft kiln by virtue of a conveyor for drying operation, step 2, a raw material accurate proportioning and mixing stage, step 3, a smelting link for completing accurate proportioning and mixing of the raw materials, and step 4, a high-hardness and high-volume-density brown aluminum oxide production process. The high-temperature precise crushing technology comprises the following steps of (1) carrying out high-temperature precise crushing on the brown aluminum oxide, and then officially entering a key smelting link, (2) completing smelting, pouring the smelted brown aluminum oxide melt into a pre-prepared specific mold, and carrying out primary solidification and crystallization by adopting a natural cooling mode, (5) carrying out hot process treatment on the brown aluminum oxide, and (6) carrying out grinding treatment on the brown aluminum oxide. Waste heat resources generated after brown aluminum oxide is smelted are fully utilized, when the materials are in a high-temperature state, the breakthrough of granularity control precision is achieved, and the hardness index reaches the Mohs hardness 9.0 level and is improved by 20% compared with a traditional material.

Description

TECHNICAL FIELD

[0001] The application is a high-hardness and high-bulk-density brown corundum process, and belongs to the technical field of brown corundum. BACKGROUND

[0002] Brown corundum, also known as diamond sand, is a kind of brown artificial corundum made of bauxite and coke as main raw materials in an electric arc furnace. The main chemical component of brown corundum is Al2O3, and the content is 95.00% to 97.00%. In addition, it contains a small amount of Fe, Si, Ti and the like. As an important industrial material, brown corundum has a wide application in the fields of abrasive tools, refractory materials and grinding tools due to its high hardness, wear resistance and high-temperature resistance. In the abrasive tool industry, brown corundum is the most basic material. Among the three major abrasive categories of ordinary abrasive, superhard abrasive and ceramic abrasive, ordinary abrasive accounts for 80% of the market share, and among the ordinary abrasive, brown corundum accounts for 80% of the share. The total amount of brown corundum used in China's abrasive industry is 450,000 tons (particle size sand) per year, of which 160,000 tons are used for resin and rubber binder abrasive tools, 170,000 tons are used for ceramic abrasive tools, and 120,000 tons are used for coated abrasive tools. In the field of refractory materials, brown corundum is widely used in high-grade refractory materials due to its good refractory performance and erosion resistance.

[0003] In the application process of abrasive tools, brown corundum with high hardness can significantly improve the efficiency of grinding work, making the grinding process more smooth and efficient, and can effectively prolong the service life of the abrasive tool and reduce the time and cost consumption caused by frequent replacement of the abrasive tool. Brown corundum with high bulk density can significantly enhance the wear resistance and cutting force of the abrasive tool, so that the abrasive tool can still maintain good working condition in long-term high-intensity use. In the manufacturing and application field of refractory materials, brown corundum with high hardness and high bulk density can significantly improve the high-temperature performance of refractory materials, so that they can still maintain stability in high-temperature environment and are not easy to deform or damage, and can effectively enhance the erosion resistance and resist the erosion of various chemicals, thereby prolonging the service life of the refractory materials. SUMMARY

[0004] In view of the deficiencies of the prior art, the application aims to provide a high-hardness and high-bulk-density brown corundum process to solve the problems in the background art. The application uses high-temperature precise crushing technology to fully utilize the waste heat resources after smelting of brown corundum. When the material is in a high-temperature state, a hydraulic driving hammer body is used to perform high-frequency impact operation. This process reduces the material hardness by 30%, reduces the wear rate of the crushing hammer by 45%, and breaks through the accuracy of particle size control.

[0005] In order to achieve the above-mentioned purpose, the application is implemented by the following technical scheme: a high-hardness and high-bulk-density brown corundum process, comprising the following steps:

[0006] Step one, raw material pretreatment, in order to send bauxite into the shaft kiln smoothly by the conveyor for drying operation, the bauxite is subjected to thorough dehydration drying treatment at a high temperature of up to 1200℃, the purpose is to completely remove the water contained in the raw material;

[0007] Step two, accurate proportioning and mixing of raw materials, in this link, first, the clinker, coke and iron filings and other basic raw materials after strict pretreatment are carefully weighed according to the pre-set accurate proportion, after the automatic weighing work is completed, the accurately weighed raw materials are then fully mixed;

[0008] Step three, smelting, after the accurate proportioning and mixing of the above raw materials, the key smelting step is entered, first, the bauxite after drying treatment is uniformly mixed with auxiliary raw materials such as anthracite and iron filings according to the accurate proportion, after mixing evenly, the mixed material is rapidly and smoothly conveyed into the electric arc furnace through the efficient feeding system, after the electric arc furnace is started, the strong current generates high temperature arc through the electrode, the temperature in the furnace is rapidly raised to an extremely high temperature above 2200℃ in a very short time, under this high temperature environment, the alumina in bauxite and other components fully react, gradually forming brown corundum crystals with high hardness and high bulk density characteristics;

[0009] Step four, smelting is completed, the smelted brown corundum melt is poured into the pre-prepared special mold, and natural cooling is used to make it preliminarily solidify and crystallize, during the cooling process, the cooling speed must be strictly controlled to avoid defects such as stress concentration and cracks in the product due to too fast cooling, after the brown corundum is cooled to room temperature, the ladle demolding treatment is carried out, and the preliminarily crystallized brown corundum is obtained;

[0010] Step five, brown corundum heat treatment, using mechanical force in high temperature environment to crush brown corundum into different sizes required by military products, using residual heat to continue the crushing operation, while ensuring the crushing effect, the brown corundum is slowly cooled down under the action of residual heat;

[0011] Step six, brown corundum abrasive treatment, in the application process of abrasive grinding tools, brown corundum with high hardness can significantly improve the efficiency of grinding work, making the grinding process more smooth and efficient, and also effectively prolonging the service life of the grinding tool, reducing the time and cost consumption caused by frequent replacement of the grinding tool, while brown corundum with high bulk density characteristics can significantly enhance the wear resistance and cutting force of the grinding tool, so that the grinding tool can still maintain good working condition in long-term high-intensity use.

[0012] Further, the bauxite is a kind of brown artificial corundum abrasive obtained by high-temperature melting reduction reaction in an electric arc furnace using high-quality bauxite, carbon materials (coke, coke, etc.) and iron filings as main raw materials, and the main chemical component is Al2O3, the content is between 94.5%-97%, and also contains a small amount of Fe, Si, Ti, etc.

[0013] Further, the brown corundum has a true specific gravity of ≥3.90g / cm 3 , and a bulk density of 1.5-1.95g / cm 3 .

[0014] The high-hard high-density brown corundum process and its preparation method of the application, the high-temperature precise crushing technology, fully utilizes the waste heat resources after the smelting of brown corundum, and the hammer body is driven by hydraulic pressure to implement high-frequency impact operation when the material is in a high-temperature state, which reduces the material hardness by 30%, reduces the wear rate of the crushing hammer by 45%, and at the same time realizes the breakthrough of particle size control accuracy, the hardness index reaches Mohs hardness 9.0 level, which is 20% higher than that of traditional materials, and can effectively resist the direct impact of armor-piercing bullets, the density breaks through 3.90g / cm 3 The above is 15% higher than the conventional product, and the chemical stability is significantly enhanced, and at a high temperature of 1800℃, the original performance can still be maintained at 100%, and the acid and alkali corrosion resistance reaches the military standard. DETAILED DESCRIPTION

[0015] In order to make the technical means, creative features, purposes and effects realized by the application easy to understand, the application will be further described below in combination with specific embodiments.

[0016] Embodiment: high-hard high-density brown corundum process, comprising the following steps:

[0017] Step one, raw material pretreatment, in order to send bauxite into the shaft kiln for drying operation smoothly by means of conveyor, the bauxite is subjected to complete dehydration drying treatment at a high temperature of up to 1200℃, the purpose is to completely remove the water contained in the raw material;

[0018] Step two, accurate proportioning and mixing stage, in this link, first, the clinker, coke and iron filings and other basic raw materials after strict pretreatment are carefully weighed according to the pre-set accurate proportion, after the automatic weighing work is completed, the raw materials after accurate weighing are fully mixed;

[0019] Step three, smelting link, after the precise proportioning and mixing of the above raw materials, the key smelting link is formally entered, first, the bauxite after drying treatment is uniformly mixed with auxiliary raw materials such as anthracite and iron filings according to the accurate proportion, after uniform mixing, the mixed material is rapidly and smoothly transported into the electric arc furnace through the efficient feeding system, after the electric arc furnace is started, the strong current generates high temperature electric arc through the electrode, so that the temperature in the furnace is rapidly increased to an extremely high temperature above 2200 DEG C in a very short time, under this high temperature environment, the alumina in bauxite and other components fully react, and gradually form brown corundum crystals with high hardness and high bulk density characteristics;

[0020] Step four, after smelting, pour the smelted brown corundum melt into the specially prepared mold, and use natural cooling to preliminarily solidify and crystallize, during the cooling process, the cooling speed must be strictly controlled to avoid stress concentration and cracks in the product due to too fast cooling, after the brown corundum is cooled to room temperature, the ladle demolding treatment is carried out, and the preliminarily crystallized brown corundum is obtained.

[0021] Step five, brown corundum heat treatment, the brown corundum is broken into different sizes required by the military product by using mechanical force in high temperature environment, and the breaking operation is continued by using waste heat, while ensuring the breaking effect, the brown corundum is slowly cooled down under the action of waste heat.

[0022] Step six, brown corundum is subjected to abrasive treatment, in the application process of abrasive grinding tools, brown corundum with high hardness can significantly improve the efficiency of grinding work, so that the grinding process is more smooth and efficient, and the service life of the grinding tool can be effectively prolonged, and the time and cost consumption caused by frequent replacement of the grinding tool can be reduced, and brown corundum with high bulk density characteristics can significantly enhance the wear resistance and cutting force of the grinding tool, so that the grinding tool can still maintain good working condition in long time and high intensity use.

[0023] Bauxite is a kind of brown corundum abrasive material obtained by high temperature >2200 DEG C melting reduction reaction in electric arc furnace with high quality bauxite, carbon materials (coke, coke, etc.) and iron filings as main raw materials, its main chemical composition is Al2O3, the content is between 94.5% and 97%, and it also contains a small amount of Fe, Si, Ti, etc., the true specific gravity of brown corundum is ≥3.90g / cm 3 , the bulk density is 1.5-1.95g / cm 3 .

[0024] The high-temperature precise crushing technology of the application makes full use of the waste heat resources of brown corundum after smelting, and the hammer body is driven by hydraulic pressure to implement high-frequency impact operation when the material is in a high-temperature state. The process makes the material hardness decrease by 30%, the wear rate of the crushing hammer decrease by 45%, and the particle size control precision is broken through. The hardness index reaches Mohs hardness 9.0 level, which is 20% higher than that of traditional materials, and can effectively resist the direct impact of armor-piercing bullets. The density breaks through 3.90 g / cm 3 Compared with the conventional product, the above is increased by 15%, and the chemical stability is significantly enhanced. At a high temperature of 1800 DEG C, the original performance can still be maintained by 100%, and the acid and alkali corrosion resistance reaches the military standard.

[0025] The above shows and describes the basic principles and main features of the application and the advantages of the application. It is obvious for those skilled in the art that the application is not limited to the details of the above exemplary embodiments, and the application can be implemented in other specific forms without departing from the spirit or essential characteristics of the application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the application.

[0026] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. High-hardness, high-density brown corundum processing, characterized by: Includes the following steps: Step 1: Raw material pretreatment. In order to smoothly feed the bauxite into the vertical kiln for drying, the bauxite is thoroughly dehydrated and dried at a high temperature of up to 1200℃. The purpose is to completely remove the moisture contained in the raw material. Step 2, the precise proportioning and mixing of raw materials: In this step, the pre-treated clinker, coke and iron filings are weighed according to the pre-set precise proportions. After the automatic weighing is completed, these precisely weighed raw materials are then fully mixed. Step 3, Smelting: After the precise proportioning and mixing of the above raw materials are completed, the crucial smelting process begins. First, the dried bauxite is mixed evenly with anthracite, iron filings, and other auxiliary raw materials in a precise ratio. After the mixture is evenly mixed, it is quickly and smoothly transported into the electric arc furnace through an efficient feeding system. After the electric arc furnace is started, a powerful current passes through the electrodes to generate a high-temperature arc, causing the furnace temperature to rise rapidly to an extreme high temperature of over 2200℃ in a very short time. Under this high-temperature environment, the raw materials begin to undergo a series of complex physicochemical reactions. The alumina in the bauxite reacts fully with other components, gradually forming brown corundum crystals with high hardness and high bulk density. Step 4: After smelting, pour the molten brown fused alumina into a pre-prepared mold and allow it to solidify and crystallize naturally. During the cooling process, the cooling rate must be strictly controlled to avoid stress concentration and cracks caused by excessive cooling. After the brown fused alumina cools to room temperature, it is then turned over and demolded to obtain the pre-crystallized brown fused alumina. Step 5: Brown fused alumina heat treatment. Using mechanical force under high temperature, brown fused alumina is crushed into different sizes required for military products. The residual heat is used to continue the crushing operation, ensuring the crushing effect while allowing the brown fused alumina to cool down slowly under the action of residual heat. Step Six: Abrasive Treatment of Brown Fused Alumina. In the application of abrasive tools, brown fused alumina, with its high hardness, can significantly improve the efficiency of grinding work, making the grinding process smoother and more efficient. At the same time, it can effectively extend the service life of the abrasive tool and reduce the time and cost consumption caused by frequent tool replacement. Brown fused alumina, with its high bulk density, can significantly enhance the wear resistance and cutting force of the abrasive tool, allowing the abrasive tool to maintain a good working condition even under long-term high-intensity use.

2. The high-hardness, high-density brown corundum process according to claim 1, characterized in that: The bauxite is a brownish-brown artificial corundum abrasive produced by melting and reducing high-temperature (>2200℃) artificial corundum abrasive in an electric arc furnace using high-quality bauxite, carbon materials (coke, etc.) and iron filings as the main raw materials. Its main chemical component is Al2O3, with a content between 94.5% and 97%, and it also contains small amounts of Fe, Si, Ti, etc.

3. The high-hardness, high-density brown corundum process according to claim 1, characterized in that: The brown fused alumina has a true specific gravity ≥ 3.90 g / cm³. 3 Bulk density 1.5-1.95 g / cm³ 3 .