阅读说明：本技术 一种用于柔性矿物绝缘电缆的氟金云母及其制备方法 (Fluorophlogopite for flexible mineral insulated cable and preparation method thereof ) 是由 符靓 黄美华 夏世全 陈先华 谢华林 李建波 于 2021-01-07 设计创作，主要内容包括：本发明公开了一种用于柔性矿物绝缘电缆的氟金云母,由以下原材料制备得到：重质氧化镁、煅烧滑石、氟硅酸钾、氧化铝粉、氟硼酸钾、四氟铝酸钾和碳酸钾。一种用于柔性矿物绝缘电缆的氟金云母的制备方法,其特征在于,按照如下步骤制备：(1)将所述重质氧化镁、煅烧滑石、氟硅酸钾、氧化铝粉、氟硼酸钾、四氟铝酸钾和碳酸钾在搅拌器中混合,使充分混合均匀；(2)用耐火砖砌出椭圆形炉体,炉体内安装石墨电极用于加热,随电极的摆放炉体的外形和炉膛均呈椭圆形；(3)将步骤1混合均匀的物料放入上述炉体内,电热煅烧熔融,然后保温、降温、冷却结晶得到氟金云母。发明氟金云母透光性非常好,吸水率低,熔点高,不含碳化残留物。(The invention discloses fluorophlogopite for a flexible mineral insulated cable, which is prepared from the following raw materials: heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate. A preparation method of fluorophlogopite for a flexible mineral insulated cable is characterized by comprising the following steps: (1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix; (2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval; (3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, performing electrothermal calcination and melting, and then performing heat preservation, cooling and crystallization to obtain fluorophlogopite. The fluorophlogopite has the advantages of good light transmittance, low water absorption, high melting point and no carbonized residue.)

1. Fluorophlogopite for flexible mineral insulated cables, characterized by being prepared from the following raw materials: heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate.

2. Fluorophlogopite for flexible mineral-insulated cables according to claim 1, characterized by being prepared from the following raw materials in parts by weight: 48-62 parts of calcined talc, 8-12 parts of heavy magnesium oxide, 15-25 parts of potassium fluosilicate, 8-16 parts of alumina powder, 1-5 parts of potassium fluoborate, 3-8 parts of potassium tetrafluoroaluminate and 2-6 parts of potassium carbonate.

3. Fluorophlogopite for flexible mineral-insulated cables according to claim 2, characterized by being prepared from the following raw materials in parts by weight: 52-60 parts of calcined talc, 8-12 parts of heavy magnesium oxide, 18-23 parts of potassium fluosilicate, 10-14 parts of alumina powder, 2-3 parts of potassium fluoborate, 4-6 parts of potassium tetrafluoroaluminate and 3-5 parts of potassium carbonate.

4. Fluorophlogopite for flexible mineral insulated cables according to any of claims 1-3, characterized in that: the contents of the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate are all more than 98 percent.

5. A process for the preparation of fluorophlogopite for flexible mineral insulated cables according to any of claims 1 to 4, characterized by the fact that it is prepared according to the following steps:

(1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix;

(2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval;

(3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, carrying out electrothermal calcination and melting, and then clarifying and crystallizing to obtain fluorophlogopite.

Technical Field

The invention relates to fluorophlogopite for a flexible mineral insulated cable and a preparation method thereof, belonging to the field of insulating materials.

Background

The flexible mineral insulated cable has a plurality of excellent characteristics which are generally accepted in practical application, reaches the international standard of safe use of universal cables, has long continuous length, and can reach 1000mm of section of a single-core cable, no matter the cable is a single-core cable or a multi-core cable²The section of the multi-core cable can reach 240mm²The cable can be coiled on a cable coil, the bending radius of the cable coil is less than or equal to 20D, the cable is insulated by adopting an inorganic material, no harmful gas is generated during combustion, secondary pollution can not occur, the cable is an environment-friendly green product, and the cable is large in current-carrying capacity and has large overload capacity.

Fluorophlogopite (KMg)₃(AlSi₃O₁₀)F₂) The fluorine ions replace hydroxyl groups, large crystals are most easily formed, and the high temperature resistance of the mica can be greatly improved. Compared with natural mica, the fluorophlogopite is more resistant to high temperature (more than 1200 ℃), has higher resistivity (1000 times higher), is more acid and alkali resistant, transparent, strippable and elastic, and is suitable for main fire-resistant insulating layers in various insulating fire-resistant cables. When the cable is burnt in open fire, the volatilization of harmful smoke is basically avoided, and the cable is effective and safe when being used.

The main components of the existing fluorophlogopite are quartz powder, fused magnesite, potassium fluosilicate, alumina powder and potassium carbonate, and the synthesis process can be mainly divided into a crucible descending seed crystal method and an internal heating method. Among them, the Bridgman method is capable of producing large crystals, but has high production costs due to its high energy consumption, long cycle time, and the need to use an expensive platinum crucible. The internal heating method mixes the required raw materials according to a certain proportion and adds the mixture into a high-temperature furnace built by refractory bricks, partial raw materials are melted by utilizing a heating electrode, the melted melt can conduct electricity, so that the raw materials are completely melted, and finally, the crystal is cooled and separated out to obtain a mica product, thus the method is the main method for producing fluorophlogopite on a large scale at present. The internal heating method has the advantages of low energy consumption and low fluoride volatilization, but because the electrode is heated unevenly, the melt after melting has poor fluidity, high melting temperature, low heat and mass transfer efficiency, uneven material heating and local high temperature easily cause raw material volatilization loss, thereby influencing the yield and performance of the fluorophlogopite.

Disclosure of Invention

In view of the above technical problems, a first object of the present invention is to provide fluorophlogopite for a flexible mineral insulated cable, and a second object is to provide a preparation method of the fluorophlogopite for the flexible mineral insulated cable. By changing the composition and the formula of the raw materials, the mass transfer and heat transfer efficiency of the fused mass in the synthesis process is improved, and the fluidity and the uniformity of the fused mass are improved, so that the yield and the quality of the fluorophlogopite are improved.

In order to achieve the first object, the technical scheme of the invention is as follows: fluorophlogopite for flexible mineral insulated cables, characterized by being prepared from the following raw materials: heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate.

Preferably, the compound is prepared from the following raw materials in parts by weight: 48-62 parts of calcined talc, 8-12 parts of heavy magnesium oxide, 15-25 parts of potassium fluosilicate, 8-16 parts of alumina powder, 1-5 parts of potassium fluoborate, 3-8 parts of potassium tetrafluoroaluminate and 2-6 parts of potassium carbonate.

Preferably, the compound is prepared from the following raw materials in parts by weight: 52-60 parts of calcined talc, 8-12 parts of heavy magnesium oxide, 18-23 parts of potassium fluosilicate, 10-14 parts of alumina powder, 2-3 parts of potassium fluoborate, 4-6 parts of potassium tetrafluoroaluminate and 3-5 parts of potassium carbonate.

Preferably, the contents of the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate are all more than 98 percent.

The second object of the present invention is achieved by: a preparation method of fluorophlogopite for a flexible mineral insulated cable is characterized by comprising the following steps:

(1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix;

(2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval;

(3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, carrying out electrothermal calcination and melting, and then clarifying and crystallizing to obtain fluorophlogopite.

According to the invention, the calcined talc and the heavy magnesium oxide are adopted to replace the traditional raw materials of fused magnesite and quartz powder for synthesizing fluorophlogopite, so that the raw material cost is reduced, the impurity content in the raw materials is reduced, and the synthesized mica prepared by matching with potassium fluoborate and potassium tetrafluoroaluminate has the advantages of very good light transmittance, low water absorption and high melting point. The potassium fluoborate provides a fluorine source and a potassium source for the synthesis of fluorophlogopite; in a molten state, fluorine ions and potassium ions (KF) generated by the decomposition of potassium fluoborate have strong penetrating power, so that a flux can permeate into the raw material compositions, the reaction efficiency is improved, the fluidity is improved, boron trifluoride generated by the decomposition of potassium fluoborate can escape in a gas form, and the purity of fluorophlogopite is not influenced. The binary eutectic system composed of potassium fluoborate and potassium tetrafluoroaluminate has eutectic temperature lower than the melting point temperature of potassium fluoborate and potassium tetrafluoroaluminate by about 100 ℃ during calcination, and can show flux characteristics when the calcination temperature reaches 445-455 ℃, thereby improving the fluidity of the molten mass. The potassium tetrafluoroaluminate provides a certain fluorine source for the synthesis of fluorophlogopite, the potassium tetrafluoroborate forms a eutectic temperature which is favorable for melting in a low-temperature state, and the low viscosity and the extremely low surface tension of the potassium tetrafluoroaluminate in the melting state can rapidly flow in various synthetic raw materials, so that the heat and mass transfer efficiency in the synthetic process is improved, the energy consumption is reduced, and the fluidity of a molten mass is improved. The hyperstabilization chemical property of the potassium tetrafluoroaluminate still escapes in a molecular state in a gas state, no residue is generated, and the purity of the fluorophlogopite is not influenced.

The synthetic mica provided by the invention takes heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate as main raw materials, and has the advantages of low cost, low energy consumption, high purity of fluorophlogopite, excellent quality and good quality. Compared with fluorophlogopite which adopts quartz powder, fused magnesite, potassium fluosilicate, alumina powder and potassium carbonate as main raw materials in the prior art, the fluorophlogopite has the advantages of very good light transmittance, low water absorption rate, high melting point and no carbonized residue.

Detailed Description

The invention is further illustrated by the following examples:

example 1

A fluorophlogopite for a flexible mineral insulated cable is prepared from the following raw materials in parts by weight: 48 parts of calcined talc, 8 parts of heavy magnesium oxide, 15 parts of potassium fluosilicate, 8 parts of alumina powder, 1 part of potassium fluoborate, 3 parts of potassium tetrafluoroaluminate and 2 parts of potassium carbonate. The contents of heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate are all more than 98 percent.

The preparation method comprises the following steps:

(1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix;

(2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval;

(3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, performing electric heating calcination until the materials are molten, and then clarifying and crystallizing to obtain the fluorophlogopite.

Example 2

A fluorophlogopite for a flexible mineral insulated cable is prepared from the following raw materials in parts by weight: 62 parts of calcined talc, 12 parts of heavy magnesium oxide, 25 parts of potassium fluosilicate, 16 parts of alumina powder, 5 parts of potassium fluoborate, 8 parts of potassium tetrafluoroaluminate and 6 parts of potassium carbonate. The contents of heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate are all more than 98 percent.

The preparation method comprises the following steps:

(1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix;

(2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval;

(3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, performing electric heating calcination until the materials are molten, and then clarifying and crystallizing to obtain the fluorophlogopite.

Example 3

A fluorophlogopite for a flexible mineral insulated cable is prepared from the following raw materials in parts by weight: 52 parts of calcined talc, 10 parts of heavy magnesium oxide, 18 parts of potassium fluosilicate, 10 parts of alumina powder, 2 parts of potassium fluoborate, 4 parts of potassium tetrafluoroaluminate and 3 parts of potassium carbonate. The contents of heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate are all more than 98 percent.

The preparation method comprises the following steps:

(1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix;

(2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval;

(3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, performing electric heating calcination until the materials are molten, and then clarifying and crystallizing to obtain the fluorophlogopite.

Example 4

A fluorophlogopite for a flexible mineral insulated cable is prepared from the following raw materials in parts by weight: 60 parts of calcined talc, 12 parts of heavy magnesium oxide, 23 parts of potassium fluosilicate, 14 parts of alumina powder, 3 parts of potassium fluoborate, 6 parts of potassium tetrafluoroaluminate and 5 parts of potassium carbonate. The contents of heavy magnesium oxide, calcined talc, potassium fluosilicate, alumina powder, potassium fluoborate, potassium tetrafluoroaluminate and potassium carbonate are all more than 98 percent.

The preparation method comprises the following steps:

(1) mixing the heavy magnesium oxide, the calcined talc, the potassium fluosilicate, the alumina powder, the potassium fluoborate, the potassium tetrafluoroaluminate and the potassium carbonate in a stirrer to fully and uniformly mix;

(2) an oval furnace body is built by refractory bricks, a graphite electrode is arranged in the furnace body for heating, and the shape of the furnace body and a hearth along with the arrangement of the electrode are oval;

(3) and (3) putting the uniformly mixed materials in the step (1) into the furnace body, performing electric heating calcination until the materials are molten, and then clarifying and crystallizing to obtain the fluorophlogopite.

The results of comparing the technical indexes of the synthetic mica prepared according to the prior art and using quartz powder, fused magnesia, potassium fluosilicate, alumina powder and potassium carbonate as main raw materials in the invention are as follows:

by contrast, the synthetic mica of the present invention has good light transmittance, low water absorption, high melting point, and almost no carbonized residue. The performance of the mica is superior to that of the synthetic mica prepared by quartz powder, fused magnesia, potassium fluosilicate, alumina powder and potassium carbonate in the prior art, and the melting temperature is low.

The present invention is not limited to the above-described embodiments, and those skilled in the art will understand that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.