Rotary kiln for improving the shape of electrotechnical grade magnesium oxide particles

Abstract

This utility model discloses a rotary kiln for improving the shape of electrical grade magnesium oxide particles. It includes a rotary kiln body with a feed inlet and a discharge outlet, and a heating device is installed inside the kiln body. The kiln body contains multiple grinding balls that collide with the magnesium oxide particles to promote surface shaping. A screen structure is also installed inside the kiln body to prevent the grinding balls from continuing to move with the material. The heating device controls the internal temperature of the rotary kiln body within a range suitable for particle softening and shaping. After entering the kiln body, the magnesium oxide particles soften and deform under the impact of the grinding balls and the high temperature provided by the heat source, gradually smoothing out sharp edges. The particles pass through the screen and enter the subsequent section for further heating and rounding, ultimately forming particles that tend to be spherical. This utility model can improve the sphericity, flowability, and tap density of electrical grade magnesium oxide, and is suitable for shaping the filler material in the manufacture of electric heating elements.

Description

Technical Field

[0001] This utility model relates to the field of magnesium oxide material processing, and in particular to a rotary kiln for improving the shape of electrical grade magnesium oxide particles, which is suitable for industrial applications that improve the sphericity of magnesium oxide particles, enhance their flowability and filling performance. Background Technology

[0002] As a key filler material for tubular heating elements, the particle shape of electrical grade magnesium oxide directly affects the filler density, electrical insulation performance, and finished product consistency. Ideally, electrical grade magnesium oxide particles should have a spherical or near-spherical structure, with good flowability and tap density.

[0003] In existing technologies, most common electrical-grade magnesium oxide particles exhibit multi-faceted, irregular, or flaky structures. Their production process typically involves raw material calcination, crushing, and screening, lacking specialized shaping treatment. This particle morphology leads to the following problems:

[0004] The large gaps between particles result in loose filling and insufficient compaction density;

[0005] When manufacturing electric heating elements, problems such as uneven shrinkage and poor pressure resistance are prone to occur.

[0006] In practical use, residual air or moisture between magnesium oxide particles may lead to safety hazards such as withstand voltage breakdown, poor insulation, abnormal leakage current, and shortened lifespan.

[0007] Therefore, there is an urgent need for a novel, integrated equipment to achieve particle shaping during the calcination of magnesium oxide, so as to improve product quality and process reliability. Utility Model Content

[0008] The purpose of this invention is to provide a rotary kiln that can simultaneously perform shaping and calcination of electrical grade magnesium oxide particles under high temperature conditions, thereby solving the problems of poor particle shape, limited shaping effect, and dispersed processes in the prior art.

[0009] To achieve the above objectives, this utility model provides the following technical solution:

[0010] A rotary kiln for improving the shape of electrical grade magnesium oxide particles includes a rotary kiln body with a feed inlet and a discharge outlet, and a heating device is provided inside the rotary kiln body.

[0011] The rotary kiln is equipped with multiple grinding balls for colliding with magnesium oxide particles to promote surface shaping.

[0012] The rotary kiln body is equipped with a screen structure to prevent the grinding balls from continuing to move with the material.

[0013] The heating device is used to control the internal temperature of the rotary kiln body within a range suitable for particle softening and shaping.

[0014] The heating device is located near the feed inlet and is used to provide the heat required for shaping immediately after the magnesium oxide particles enter.

[0015] The rotary kiln body is also equipped with an air inlet and a dust removal exhaust outlet to control the atmosphere inside the kiln and remove dust.

[0016] The aperture of the screen structure is smaller than the diameter of the grinding ball, but larger than the maximum particle size of the electrical grade magnesium oxide particles.

[0017] The grinding balls are made of high-purity alumina ceramic, zirconium oxide ceramic, or tungsten carbide alloy.

[0018] Compared with the prior art, the beneficial effects of this utility model are mainly reflected in:

[0019] Particle shaping at high temperatures softens the edges and corners of the particles, making them easier to deform and resulting in higher shaping efficiency.

[0020] The kiln is equipped with a structure that combines grinding balls and screens, enabling simultaneous shaping and sorting operations.

[0021] This integrates the shaping and calcining processes, simplifying the workflow, reducing energy consumption, and improving product consistency.

[0022] After shaping, the magnesium oxide particles tend to be spherical, and their flowability, tap density and electrical properties are significantly improved. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the rotary kiln of this utility model.

[0024] in:

[0025] 1 - Rotary kiln body;

[0026] 2 - Feed inlet;

[0027] 3 - Discharge port;

[0028] 4 - Air inlet;

[0029] 5 - Dust removal and exhaust vents;

[0030] 6 - Heat source;

[0031] 7 - Grinding ball;

[0032] 8 - Mesh screen. Detailed Implementation

[0033] The specific structure and working principle of this utility model will be described in detail below with reference to the accompanying drawings.

[0034] like Figure 1 As shown, this utility model includes a rotary kiln body 1, which is provided with a feed inlet 2, a discharge outlet 3, an air inlet 4, and a dust removal and exhaust outlet 5. A heat source 6 is provided inside the kiln body, which can control the kiln temperature within the range of 300℃ to 1200℃.

[0035] Several grinding balls 7 are arranged near the feed inlet 2, which tumble as the kiln body 1 rotates, and are used to repeatedly collide with the magnesium oxide particles. The grinding balls are made of high-purity alumina ceramic, zirconium oxide ceramic or tungsten carbide alloy to ensure their wear resistance and chemical inertness at high temperatures.

[0036] Magnesium oxide particles enter the kiln body through feed inlet 2 and tumble together with grinding balls 7. The particles soften due to heat and are deformed by the impact of the grinding balls. The original sharp edges are ground down and gradually become spherical.

[0037] A screen 8 is installed in the middle of the kiln body. Its aperture is smaller than the diameter of the grinding ball 7 but larger than the maximum particle size of magnesium oxide particles. Therefore, as the material moves towards the discharge port 3 with the rotation, the grinding ball 7 is blocked by the screen 8 and remains in the front section, while the shaped magnesium oxide particles can pass through the screen holes into the rear section. The mutual friction between particles and the rotation of the particles themselves can make the surface of the particles smooth and the edges tend to be rounded, promoting the formation of spherical magnesium oxide particles.

[0038] After being shaped by this equipment, the magnesium oxide particles become more rounded, effectively improving their fillability, electrical performance, and safety in use.

[0039] It should be noted that the above are only preferred embodiments of this utility model. Those skilled in the art can make equivalent improvements to the structural form, material selection, heating method, etc., without departing from the spirit of this utility model, and all such improvements should fall within the protection scope of this utility model.

Claims

1. A rotary kiln for improving the shape of electrical grade magnesium oxide particles, comprising a rotary kiln body with a feed inlet and a discharge outlet, wherein a heating device is provided inside the rotary kiln body, characterized in that: The rotary kiln is equipped with multiple grinding balls for colliding with magnesium oxide particles to promote surface shaping. The rotary kiln body is equipped with a screen structure to prevent the grinding balls from continuing to move with the material. The heating device is used to control the internal temperature of the rotary kiln body within a range suitable for particle softening and shaping.

2. The rotary kiln according to claim 1, characterized in that: The heating device is located near the feed inlet and is used to provide the heat required for shaping immediately after the magnesium oxide particles enter.

3. The rotary kiln according to claim 1, characterized in that: The rotary kiln body is also equipped with an air inlet and a dust removal exhaust outlet to control the atmosphere inside the kiln and remove dust.

4. The rotary kiln according to claim 1, characterized in that: The aperture of the screen structure is smaller than the diameter of the grinding ball, but larger than the maximum particle size of the electrical grade magnesium oxide particles.

5. The rotary kiln according to claim 1, characterized in that: The grinding balls are made of high-purity alumina ceramic, zirconium oxide ceramic, or tungsten carbide alloy.

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