Mangan zinc ferrite resintering process

A manganese-zinc ferrite and process technology, which is applied in the field of manganese-zinc ferrite back-burning process, can solve problems such as excessive oxidation of products, economic loss of enterprises, and slow oxidation speed

Active Publication Date: 2011-04-13
YIBIN JINCHUAN ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0018] (4) When the temperature continues to drop to about 600°C, if the partial pressure of oxygen in the surrounding atmosphere is high, MnFe 2 o 4 The divalent manganese ions in will also be oxidized to trivalent manganese ions, but due to the lower temperature, the oxidation rate slows down
[0021] (5) When the system temperature drops to the range of 300-250°C, a large amount of α-Fe 2 o 3 Will form acicular phase, which will seriously affect the performance of manganese zinc ferrite products
[0023] In the long-term production process, sometimes due to faults, the tail of the kiln enters the air, or due to reasons such as the reduction of nitrogen purity, the product is excessively oxidized during the cooling process, and the specific manifestation is abnormal surface color.
The traditional treatment method is to treat these products as bad products or scrap products, which brings economic losses to the enterprise and wastes resources to the society.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Put the manganese-zinc ferrite product with abnormal color on the surface of excessive sintering sintering in the kiln for heating. Oxygen content≤0.02%), the oxygen content at 900°C-1000°C is controlled according to the following formula:

[0039] log(Po 2 ) T =log(Po 2 ) 1 +[log(Po 2 ) 1 -log(Po 2 ) 2 ](T-900) / 100

[0040] In the formula, log(Po 2 ) T is the partial pressure of oxygen at temperature T, log(Po 2 ) 1 Oxygen partial pressure (0.01%) at 900°C, log(Po 2 ) 2 is the partial pressure of oxygen (0.2%) at 1000°C, and T is the temperature in °C. The initial sintering temperature of this product is 1360°C, and the maximum temperature is 1000°C when it is refired. When it reaches 1000°C, it enters the heat preservation stage. The heat preservation time is 0.5h, and the oxygen content in the heat preservation stage is set to 0.2%. The cooling stage is controlled by the traditional sintering process. After the cooling is completed, the surface color o...

Embodiment 2

[0042] Put the manganese-zinc ferrite product with abnormal color on the surface of excessive sintering sintering in the kiln for heating, the average heating rate is 300°C / h, from room temperature to 500°C in air atmosphere, 500-900°C in nitrogen atmosphere ( Oxygen content ≤ 0.02%), the initial sintering temperature of this product is 1360°C, and the maximum temperature during back-burning is also 1360°C, which is the same as the green body sintering temperature of this product, the holding time is 3h, and the oxygen content in the holding stage is 7.5%. The oxygen content at 900-1360°C is controlled according to the following formula:

[0043] log(Po 2 ) T =log(Po 2 ) 1 +[log(Po 2 ) 1 -log(Po 2 ) 2 ](T-900) / 460

[0044] In the formula, log(Po 2 ) T is the partial pressure of oxygen at temperature T, log(Po 2 ) 1 is the partial pressure of oxygen (0.01%) at a temperature of 900°C, log(Po 2 ) 2 is the partial pressure of oxygen (7.5%) at 1360°C, and T is the tem...

Embodiment 3

[0046] Put the manganese-zinc ferrite product with abnormal color on the surface of excessive sintering sintering in the kiln for heating. Oxygen content ≤ 0.02%), the initial sintering temperature of this product is 1360°C, the maximum temperature at the time of reburning is 1100°C, the holding time is 0.5h, and the oxygen content in the holding stage is 0.5%. The oxygen content at 900-1100°C is controlled according to the following formula:

[0047] log(Po 2 ) T =log(Po 2 ) 1 +[log(Po 2 ) 1 -log(Po 2 ) 2 ](T-900) / 200

[0048] In the formula, log(Po 2 ) T is the partial pressure of oxygen at temperature T, log(Po 2 ) 1 is the partial pressure of oxygen (0.01%) at a temperature of 900°C, log(Po 2 ) 2 is the partial pressure of oxygen (0.5%) at 1100°C, and T is the temperature in °C. The cooling stage is controlled by the traditional sintering process. After the cooling is completed, the surface color of the product is normal, and a qualified manganese-zinc ferri...

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Abstract

The invention relates to a mangan zinc ferrite resintering process. A superoxidized mangan zinc ferrite ripe blank product is put into a kiln for heating, wherein the atmosphere is air or nitrogen atmosphere at the temperature of between room temperature and 500 DEG C, is nitrogen atmosphere at the temperature of between 500 and 900 DEG C, and is balanced oxygen partial pressure or weakly reducing atmosphere at the temperature of above 900 DEG C on the premise that the product is not cracked; and the lowest keeping temperature for resintering is 1,000 DEG C, and the highest temperature is thetemperature at which a raw blank of the product is sintered and is kept for 0.5 to 3 hours, and a heat preservation period atmosphere and a temperature reduction process can be controlled according to the conventional sintering process. By the implementation of the process, a mangan zinc ferrite waste product of which the surface color is abnormal due to oxidation is converted into a product of which the surface color is normal. Meanwhile, a product with ultralong size due to low primary sintering temperature or short temperature keeping time can be changed into a product of the normal size and surface color after being resintered.

Description

Technical field [0001] The invention relates to a magnetic material production process, in particular to a manganese-zinc ferrite back-burning process. Background technique [0002] Manganese zinc ferrite is made of MnO-ZnO-Fe 2 o 3 Composite ferrite composed of three main components. Manganese-zinc ferrite material has the characteristics of high magnetic permeability, high saturation magnetic flux density, and low loss, and is widely used in household appliances, network communications, automotive electronics, aerospace and other fields. [0003] In the traditional sintering process, the green body of manganese zinc ferrite is sintered in a kiln at high temperature, which can be roughly divided into a heating stage, a heat preservation stage and a cooling stage. In the heating stage, from room temperature to 600°C (especially 200-400°C) is the rubber discharge section, the heating rate is slow, and the average speed is not higher than 100°C / h, and the heating rate is fa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/26C04B35/64
Inventor 黄伟李良俊石庆辉段树彬胡健李文庆徐晓利陈兴贵
Owner YIBIN JINCHUAN ELECTRONICS
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