阅读说明：本技术 一种防潮型防火电缆用氧化镁及其用途 (Magnesium oxide for moisture-proof fireproof cable and application thereof ) 是由 李广明 张呈呈 田剑 郭兴凯 宋娜 刘永利 王利祥 于 2020-05-18 设计创作，主要内容包括：本发明提供一种防潮型防火电缆用氧化镁及其用途。防潮型防火电缆用氧化镁包括重量配比如下的各组分：MgO 95-99份；CaO 0.5-2.0份；Fe<Sub>2</Sub>O<Sub>3</Sub> 0.3-1.0份；Al<Sub>2</Sub>O<Sub>3</Sub> 0.1-0.6份；SiO<Sub>2</Sub> 1.0-4.0份；水(LOI)≤0.2份。本发明还公开了防潮型防火电缆用氧化镁的制备方法和防潮型防火电缆用氧化镁在电缆领域的用途。本发明防潮型防火电缆用氧化镁具有优异的防潮绝缘性能,在湿度80％RH,5小时的情况下,绝缘仍≥1000MΩ。(The invention provides magnesium oxide for a moisture-proof fireproof cable and application thereof. The magnesium oxide for the moisture-proof fireproof cable comprises the following components in parts by weight: 95-99 parts of MgO; 0.5-2.0 parts of CaO; fe 2 O 3 0.3-1.0 part; al (Al) 2 O 3 0.1-0.6 part; SiO 2 2 1.0-4.0 parts; water (LOI) is less than or equal to 0.2 portion. The invention also discloses a preparation method of the magnesium oxide for the moisture-proof fireproof cable and application of the magnesium oxide for the moisture-proof fireproof cable in the field of cables. The magnesium oxide for the moisture-proof fireproof cable has excellent moisture-proof insulating property, and the insulation is still more than or equal to 1000 MOmega under the conditions that the humidity is 80% RH and the time is 5 hours.)

1. The magnesium oxide for the moisture-proof fireproof cable is characterized by comprising the following components in parts by weight:

2. the magnesium oxide for moisture-proof fireproof cable according to claim 1, wherein the magnesium oxide comprises the following components in parts by weight:

3. the magnesium oxide for moisture-proof fireproof cable according to claim 1 or 2, wherein the MgO is subjected to high-intensity electromagnetic separation to remove magnetic substances.

4. The magnesium oxide for moisture-proof fireproof cable as claimed in claim 3, wherein the high-strength electromagnetic magnetic field strength is 10000-15000 gauss.

5. Use of the magnesium oxide for moisture-proof fireproof cable according to any one of claims 1 to 4 in the field of cables.

Technical Field

The invention relates to a material technology, in particular to magnesium oxide for a moisture-proof fireproof cable and application thereof.

Background

The safety of the electrical lines is of critical importance, whether in a factory or in a building. According to the statistics of relevant departments of the country, the fire caused by an electric line accounts for more than 50% of the causes of the fire. The cable is a main body in the circuit and is a link difficult to protect. Therefore, the cable should not only have the capability of resisting the damage of external flame, but also have the characteristic of not generating fire source by itself. Because the mineral insulated cable is made of inorganic materials, the magnesium oxide insulator can not generate open fire when in overload or short circuit. Therefore, the line formed by the mineral insulated cable can never cause fire. If a fire is caused by other reasons, the cable is not only tested by the big fire of the bear but also continuously impacted by other falling objects in the process of burning. At the moment, whether the cable can ensure the normal starting of fire-fighting equipment, the extinguishing of fire and the evacuation of personnel while generating no smoke and toxic gas is the key for evaluating the fire resistance of the line.

At present, under the conditions that the temperature is 25 ℃, the humidity is 80 percent RH and the temperature is 3 hours, the insulation of the insulated cable made of magnesium oxide is reduced from 500M omega to 0.5M omega. And before the cable is manufactured, the raw materials need to be baked at high temperature, so that moisture in the raw materials is removed, and the process difficulty is increased. The maximum normal working high temperature of the cable can reach 250 ℃, and the working time is short when the temperature is more than or equal to 700 ℃.

Disclosure of Invention

The invention aims to provide a moisture-proof magnesium oxide for a fireproof cable, aiming at the problems that the moisture resistance of the cable insulated by the magnesium oxide is poor and the insulation performance is obviously reduced after the cable is wetted, wherein the material has excellent moisture-proof insulation performance, and the insulation is still more than or equal to 1000 MOmega under the conditions that the humidity is 80% RH and the time is 5 hours.

In order to achieve the purpose, the invention adopts the technical scheme that: the magnesium oxide for the moisture-proof fireproof cable comprises the following components in parts by weight:

further, the magnesium oxide for the moisture-proof fireproof cable comprises the following components in parts by weight:

further, MgO is subjected to high-intensity electromagnetic separation to remove magnetic substances.

Further, the high-intensity electromagnetic field selection intensity is 10000-15000 gauss.

The preparation method of the magnesium oxide for the moisture-proof fireproof cable comprises the following steps: magnesium oxide, kaolin talc, aluminum hydroxide and zirconium silicate are mixed according to the weight ratio of 100: 3-6:2-5:1-3: 10-20; high-hydrogen-content organic silicon resin, high-hydrogen-content organic silicon oil, an aluminate coupling agent and solvent oil are mixed according to the volume ratio of 3-5: 4-6: preparing the solution according to the ratio of 20-30: 60-80; mixing the mixed materials and the solution according to the weight ratio of 80-110: 2-6 to obtain a mixed wet material; and drying the mixed wet material in a low-temperature rotary furnace at 150-300 ℃ for 1-2 hours to obtain the magnesium oxide for the moisture-proof fireproof cable.

Further, the preparation method of the magnesium oxide for the moisture-proof fireproof cable comprises the following steps:

step 1), removing magnetic substances in the fused magnesia by high-strength electromagnetic separation of the fused magnesia particles;

step 2), treating the fused magnesia particles for 60-120 minutes by a high-temperature rotary furnace at 1100-1200 ℃, and removing magnetic substances in the magnesia by high-strength electromagnetic separation;

step 3) placing kaolin into a muffle type rotary kiln, and calcining for 2-4 hours at 700-800 ℃;

step 4), carrying out surface modification treatment on the kaolin subjected to fine classification (fine classification is carried out by adopting an LHB type turbine type airflow classifier) and calcination by using a surface modification machine; obtaining superfine calcined kaolin with d less than or equal to 0.05mm and the content of 90% +/-3%;

step 5) placing the talc in a vertical drier to dry for 1-3 hours at 500-600 ℃; carrying out ultrafine grinding on the talc to 500-1000 meshes;

step 6) baking the aluminum hydroxide powder at 250-350 ℃ for 1-2 hours;

step 7) baking zirconium silicate powder at 750-850 ℃ for 1-3 hours;

step 8), mixing the magnesium oxide, kaolin talc, aluminum hydroxide and zirconium silicate obtained in the step according to the weight ratio of 100: 3-6:2-5:1-3: 10-20;

step 9), mixing the high hydrogen-containing organic silicon resin, the high hydrogen-containing organic silicon oil, the aluminate coupling agent and the solvent oil according to the volume ratio of 3-5: 4-6: preparing the solution according to the ratio of 20-30: 60-80;

step 10) mixing the materials obtained in the step 8) and the solution obtained in the step 9) according to the weight ratio of 80-110: 2-6 to obtain a mixed wet material;

and step 11) drying the mixed wet material in a low-temperature rotary furnace at the temperature of 150-300 ℃ for 1-2 hours to obtain the magnesium oxide for the moisture-proof fireproof cable.

Further, the particle size of the fused magnesia particles in the step 1 is 60-400 meshes, and the fused magnesia particles are prepared by crushing fused magnesia raw materials through a crusher.

Furthermore, the kaolin d in the step 2) is less than or equal to 20mm, the kaolin raw material is crushed by a jaw crusher and finely classified to form fine classification, the d is mainly less than or equal to 20mm, and an LHB type turbine airflow classifier is adopted for fine classification.

Further, the surface modifier in the step 4) comprises 0.05% of organic silicon resin and 0.1% of solvent oil, and the modification method is a chemical coating method.

Further, the d of the talc in the step 5) is less than or equal to 10mm, and the talc is formed by crushing talc raw materials through a hammer crusher.

Further, the content of acid-insoluble substances in the talc in the step 5) is more than or equal to 93.0 percent, and the acid-soluble iron (Fe)₂O₃) Less than or equal to 0.20 percent, the ignition loss (1200 ℃) less than or equal to 3.00 percent, the magnet absorption less than or equal to 0.03 percent and the water less than or equal to 0.3 percent.

The invention also discloses application of the magnesium oxide for the moisture-proof fireproof cable in the field of cables. The magnesium oxide for the moisture-proof fireproof cable does not need to be baked before use, and the magnesium oxide is filled between a cable core rod and the surface along with the manufacture of the cable, so that the magnesium oxide has the effects of insulation, high temperature resistance and fire resistance. The dosage and the using method are different according to different cable manufacturing processes.

Compared with the prior art, the magnesium oxide for the moisture-proof fireproof cable has the following advantages:

1) the cable manufactured by the magnesium oxide for the moisture-proof fireproof cable can still have the insulation more than or equal to 1000 MOmega under the conditions of 25 ℃ of temperature, 80% RH of humidity and 5 hours.

2) Before the magnesium oxide for the moisture-proof fireproof cable is used for manufacturing the cable, magnesium powder does not need to be baked, the production process is simplified, and the productivity and the working efficiency are improved.

3) The maximum normal working temperature of the cable manufactured by the magnesium oxide for the moisture-proof fireproof cable can reach 280 ℃, and the cable can continue to operate at the temperature close to the melting point of copper and 1083 ℃ in a short period of time. Maintaining circuit integrity provides valuable time for safe evacuation of personnel.

Detailed Description

The invention is further illustrated by the following examples: