Magnesium oxide powder is very common in our electric heater industry, and we have some understanding of it. It plays a decisive role in the electric heating tube. In order to allow everyone to fully understand the role of magnesium oxide powder in the electric heating tube and For more knowledge, the company organizes its information as follows:
What is magnesium oxide powder? Magnesium oxide (MgO) is commonly known as magnesite, light burnt powder, and magnesia powder. Density 2.94, light yellow powder. The melting point is 2852°C and the boiling point is 3600°C. It is soluble in acid and ammonium salt, but hardly soluble in water and ethanol. When the calcination temperature is 400℃, the specific surface area is 180m2/g. The specific surface area is only 3m2/g at 1300℃. Easily deliquescence in the air. It is a gas-hard cementing material. Magnesium oxide powder is divided into: high-grade lubricant grade magnesium oxide, food grade magnesium oxide, medical grade magnesium oxide, silicon steel grade magnesium oxide, high-grade electromagnetic grade magnesium oxide, high-purity magnesium oxide, and part of the magnesium oxide powder is used to make refractory materials.
Magnesium Oxide Powder
Our industry uses industrial magnesium oxide powder. The main function is that the fused crystalline magnesium oxide block is crushed and matched with different particle sizes or numbers in a certain proportion, directly or modified, used in tubular electric heating elements as a high temperature Under the thermally conductive insulating medium. In the electric heating tube, it mainly plays the role of fixing the center position of the resistance wire, ensuring that the metal shell is not charged (insulating), and conducting the heat emitted by the resistance wire.
According to the production method and main purpose, it can be divided into the following four categories:
1. Common type Classification code P
2. Low temperature and moisture-proof type Classification code D
3. Medium temperature moisture-proof type classification code Z
4. High temperature type classification code G
Performance requirements of magnesium oxide powder:
1. When MgO powder is at working temperature, it must have high thermal conductivity, so as to quickly transfer heat to the surface of the tube, and make the resistance wire closer to the tube wall temperature;
2. When the working temperature is within 1100℃, MgO powder should have good insulation properties;
3. MgO powder must have a certain degree of granularity, and the shape is generally round rather than flakes currently produced in my country. Because the round powder has high density, good fluidity, and a certain percentage of particles, it is not easy to add powder Damage the heating wire to ensure that the powder can be filled without difficulty;
4. MgO powder should not corrode heating wire materials and pipes at room temperature or high temperature.
5. The water absorption rate of magnesium oxide powder shall not be higher than the following regulations:
1. Ordinary type ≤1.5%
2. Low temperature and moisture-proof type ≤0.05%
3. Medium temperature moisture-proof type ≤0.10%
4. High temperature type ≤0.10%
The resistivity of magnesium oxide powder shall not be lower than the value specified in the following table:
The resistivity of magnesium oxide powder shall not be lower than the value specified in the following table:
Temperature ℃ 600 700 800 875 900 975 1000 1100
Resistivity Ω. cm 5×109 1.5×109 3×108 8×107 5×107 1.4×107 1.0×107 3×106
Note:
1. The selected test temperature is between the above temperature points, and the resistivity is determined by linear interpolation,
2. Select two points T1 and T2 in the test temperature range from T minus 50℃ to T plus 100℃, and T2 minus T1 is equal to 100℃, high temperature magnesium oxide T2 is equal to 975℃, and T1 is equal to 875℃.
