Design method for preparing electric furnace bottom refractory material for rock wool from long-life hot molten slag, furnace bottom and electric furnace

Abstract

The invention discloses a design method for preparing electric furnace bottom refractory for rock wool from long-life hot molten slag, a furnace bottom and an electric furnace. The design method comprises the following steps that S1, a multi-layer refractory heat preservation structure is adopted for laying the furnace bottom of the electric furnace, and a working layer laid by magnesium-calcium ramming materials is adopted for the top of the multi-layer refractory heat preservation structure; the top of the working layer is designed into an arc-shaped structure with a concave middle part; and S2, before the electric furnace is started, iron metal is put into the furnace to form a molten iron layer on a furnace bottom working layer, and then in the preparation process of rock wool melt, molten iron is discharged regularly through an iron outlet in the lower portion of the furnace wall. The arc-shaped structure formed by laying the magnesium-calcium ramming material is used as the electric furnace bottom, the molten iron layer is used for isolating the rock wool melt from the furnace bottom refractory material, the rock wool melt is prevented from making contact with the furnace bottom refractory material, the service life of the electric furnace bottom refractory material is greatly prolonged, the production halt time of a production line due to maintenance of the electric furnace refractory material is shortened, and therefore the operation rate of the rock wool production line made of the hot molten slag is increased.

Description

Technical Field

[0001] The invention relates to a rock wool preparation technology, and more specifically to a design method for an electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag, a furnace bottom and an electric furnace. Background Art

[0002] Mineral (rock) wool is an inorganic fiber insulation material with the advantages of Class A non-combustibility, heat preservation, sound insulation, light weight, good durability, etc. It is widely used in building insulation and industrial insulation. The product is made of natural rocks or slag and other raw materials melted at high temperature, and formed by the combined action of centrifugal force and wind. Professionally, mineral wool and rock wool adopt the fiber acidity coefficient Mk=(W SiO2 +W Al2O3 ) / (W CaO +W MgO ), the acidity coefficient ≥1.6 is called rock wool, and the acidity coefficient <1.6 is called mineral wool.

[0003] At present, the manufacturing process of mineral (rock) wool has the following characteristics: cupola melting and electric melting furnace melting coexist, cold material production and hot slag raw material production coexist. Rock wool products are mainly made of cold material (basalt, dolomite, dry slag) as the main raw material, and adopt the manufacturing process of electric furnace or cupola melting; the products prepared by hot slag raw materials are all slag wool, single electric furnace melting process, adding a certain proportion of quenching and tempering materials, and the products are mainly granular wool and slag wool board.

[0004] In the production process of mineral (rock) wool, the equipment used to melt raw materials is mainly electric furnace, which uses graphite as electrode and uses the heat generated by electric current passing through the resistor to heat and melt the material. Under normal circumstances, the temperature of the melt in the furnace is controlled at about 1500℃; combined with Figure 1 As shown, the furnace body consists of three parts: a furnace cover 1, a furnace wall 2 and a furnace bottom 3; the furnace cover 1 is composed of several steel plates with water-cooling jackets, which are connected together at the furnace top and integrally cast by refractory castables. A graphite electrode 4 is installed on the furnace cover 1. The furnace wall 2 is generally an annular cylinder made of steel. The total height of the outer shell of the furnace wall 2 is about 3 to 3.5 m. There is an open or closed cooling water system 7 outside the furnace wall 2. The furnace wall 2 is provided with a slag outlet 6, and an iron outlet 5 is provided on the furnace wall on the other side of the slag outlet. The furnace bottom 3 is supported by a steel structure and paved with refractory materials. In the entire production process, the service life of electric furnace refractory materials has become an important factor affecting the operating rate of the production line. Generally, carbonaceous ramming materials 8 (directly in contact with the melt), high-alumina bricks 9 and thermal insulation refractory bricks 10 are often used as refractory materials for the bottom of the electric furnace. The thickness of the carbonaceous ramming materials 8 is 500 to 600 mm, and the shape is a flat structure (see Figure 2 The service life is basically more than 2 years, ensuring the stable operation of the production line.

[0005] In recent years, in order to achieve the goal of energy conservation and carbon reduction in the mineral (rock) wool industry, cotton making technology has been further developed, the raw materials used in the preparation of mineral (rock) wool have been adjusted, the use of natural mineral resources such as basalt and dolomite has been reduced, and the application of hot blast furnace slag has made a breakthrough in the technology of rock wool making. However, in the production process of rock wool using hot blast furnace slag, which is different from the tempering process of mineral wool made from hot molten slag, due to the addition of tempering materials containing iron oxide components, the carbonaceous components in the furnace bottom refractory react with the iron oxide in the melt to undergo a reduction reaction, and the furnace bottom refractory is rapidly corroded, with a service life of only 3 to 4 months. In addition, each refractory maintenance requires shutdown for more than 20 days of inspection and maintenance, which seriously reduces the operating rate of the mineral wool production line, resulting in not only low production line output, but also increased processing costs of the production line. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of the present invention is to provide a design method and a furnace bottom and an electric furnace for long-life hot molten slag for preparing rock wool. An arc structure paved with magnesium-calcium ramming material is used as the bottom of the electric furnace, and a molten iron layer is used to isolate the rock wool melt and the furnace bottom refractory material to prevent the rock wool melt from contacting the furnace bottom refractory material, thereby greatly improving the service life of the electric furnace bottom refractory material and reducing the production line downtime due to maintenance of the electric furnace refractory material, thereby improving the operation rate of the hot molten slag rock wool production line.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a design method for an electric furnace bottom refractory material for preparing rock wool using long-life hot molten slag, comprising the following steps:

[0009] S1, using a multi-layer refractory insulation structure to pave the bottom of the electric furnace, the top of the multi-layer refractory insulation structure uses a working layer paved with magnesium-calcium ramming material, and the top of the working layer is designed to be an arc-shaped structure with a concave middle;

[0010] S2, before starting the electric furnace, iron metal is first put into the furnace to form a molten iron layer on the working layer at the bottom of the furnace. Later, during the preparation of the rock wool melt, the molten iron is regularly discharged through the iron outlet at the bottom of the furnace wall.

[0011] Preferably, in step S1, the multi-layer refractory insulation structure of the electric furnace bottom further includes a high-alumina brick layer and a thermal insulation refractory brick layer arranged below the working layer from top to bottom;

[0012] The thickness of the working layer is 540-600 mm, the thickness of the high-alumina brick is 360-440 mm, and the thickness of the thermal insulation refractory brick layer is 180-220 mm.

[0013] Preferably, the chemical composition of the magnesium-calcium ramming material of the working layer is as follows by mass percentage: MgO 80-90%, CaO 8-12%, Fe2O3 3-4%;

[0014] In the high-alumina brick layer, the mass percentage content of Al2O3 is 50-60%, and the mass percentage content of Fe2O3 is 1-1.5%;

[0015] The chemical composition of the thermal insulation refractory brick layer is calculated by mass percentage as follows: Al2O3 40-45%, SiO2 50-55%, and Fe2O3 1-1.5%.

[0016] Preferably, the refractory temperature of the working layer is 1500-1600°C and the density is 2.3-2.5 g / cm 3 ;

[0017] The density of the high alumina brick layer is 2.3-2.7 g / cm 3 , cold pressing strength ≥78MPa;

[0018] The density of the thermal insulation refractory brick layer is 0.75-0.8 g / cm 3 , cold pressing strength ≥1.7MPa.

[0019] Preferably, the arc radius of the arc structure is 40-46 m, and the arc center angle is 6-7 degrees.

[0020] Preferably, in step S2:

[0021] The input amount of the iron metal is 8 to 12 tons;

[0022] During the rock wool melt preparation process, the height of the molten iron layer in the furnace is regularly checked. When the molten iron layer exceeds the upper limit height of the tap hole, the molten iron is discharged through the tap hole at the lower part of the furnace wall.

[0023] Preferably, in step S2:

[0024] In the process of preparing the rock wool melt, the quenching and tempering material used contains iron oxide, and the mass percentage of the iron oxide is 8-20%;

[0025] The mass percentage components of the rock wool melt are: SiO2 40-45%, Al2O3 12-15%, MgO 5-7%, CaO 26-30%, and iron oxide 4-6%.

[0026] The second aspect of the present invention provides a long-life hot molten slag electric furnace bottom for preparing rock wool prepared by the design method of the long-life hot molten slag electric furnace bottom refractory material for preparing rock wool according to the first aspect of the present invention, wherein the electric furnace bottom adopts a multi-layer refractory insulation structure, which includes a working layer, a high-alumina brick layer and a thermal insulation refractory brick layer arranged from top to bottom;

[0027] The working layer is paved with magnesium-calcium ramming material, and the top of the working layer is an arc-shaped structure with a concave middle;

[0028] The bottom of the electric furnace also includes a molten iron layer formed on the working layer by throwing iron metal into the furnace before the electric furnace is started.

[0029] The third aspect of the present invention provides a long-life electric furnace for preparing rock wool with hot molten slag, comprising the bottom of the electric furnace for preparing rock wool with long-life hot molten slag as described in the second aspect of the present invention.

[0030] The effects of the present invention are as follows:

[0031] The present invention adopts magnesium-calcium ramming material as the refractory material for the furnace bottom, and changes the structure of the refractory material. The magnesium-calcium ramming material is laid into an arc structure for collecting and storing molten iron, and the molten iron layer is used to isolate the rock wool melt and the refractory material for the furnace bottom to prevent the rock wool melt from contacting the refractory material, thereby preventing the refractory material for the furnace bottom from chemical corrosion, greatly improving the service life of the refractory material for the electric furnace bottom, reducing the production line downtime due to the maintenance of the electric furnace refractory material, thereby improving the operation rate of the hot slag rock wool production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of an electric furnace for producing mineral wool using hot molten slag in the prior art;

[0033] Figure 2 It is a schematic diagram of the structure of the refractory material of the bottom of an electric furnace used for making mineral wool from hot molten slag in the prior art;

[0034] Figure 3 It is a schematic structural diagram of an electric furnace bottom refractory material for preparing rock wool using long-life hot molten slag according to the present invention;

[0035] Figure 4 It is a schematic diagram of the temperature field distribution of the electric furnace used for preparing rock wool with long-life hot molten slag of the present invention;

[0036] In the figure, 1. furnace cover; 2. furnace wall; 3. furnace bottom; 4. graphite electrode; 5. iron outlet; 6. slag outlet; 7. cooling water system; 8. carbonaceous ramming material; 9. high alumina bricks; 10. thermal insulation refractory bricks; 20. furnace wall; 21. slag outlet; 22. molten iron layer; 23. working layer; 24. high alumina brick layer; 25. thermal insulation refractory brick layer; 26. iron outlet. DETAILED DESCRIPTION

[0037] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] In order to seek the longevity technology of the refractory materials of the bottom of the electric furnace made of rock wool from hot molten slag, chromium castables, carbon ramming materials and silicon carbide castables were selected for the refractory materials of the bottom of the furnace, and industrial tests were carried out one by one. After being put into production, the monitored temperature of the furnace bottom rose rapidly. After 3 to 4 months, it was found that the central part of the refractory materials of the bottom of the electric furnace was corroded by 500mm, and production could not be maintained, and maintenance was required. Experiments have shown that the refractory materials of the bottom of the electric furnace are rapidly corroded and have a short life under the combined effects of thermal erosion, chemical erosion and melt flow erosion. It can be seen that the refractory material is not the key to the longevity technology. The refractory structure is changed. The present invention adopts the use of a molten iron layer to isolate the rock wool melt and the refractory material to prevent the melt from contacting the refractory layer, thus solving the problem of short service life of the refractory materials at the bottom of the furnace.

[0039] Combination Figure 3 As shown, the present invention provides a design method for an electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag, comprising the following steps:

[0040] S1, using a multi-layer refractory insulation structure to pave the bottom of the electric furnace, the top of the multi-layer refractory insulation structure uses a working layer paved with magnesium-calcium ramming material, and the top of the working layer is designed to be an arc-shaped structure with a concave middle;

[0041] This step is mainly to design the refractory structure of the electric furnace bottom, combined with Figure 3 As shown, the bottom of the electric furnace is paved with a multi-layer refractory insulation structure, and the top of the multi-layer refractory insulation structure is set as a working layer 23 paved with magnesium-calcium ramming material; the top of the working layer 23 is an arc-shaped structure with a concave middle, so as to collect and store molten iron. A molten iron layer 22 is formed by placing a portion of iron metal on the bottom working layer 23 before starting the furnace, so that there is a layer of molten iron layer 22 between the rock wool melt and the refractory material of the bottom working layer 23, which can effectively isolate the contact between the refractory material and the melt to prevent chemical erosion. Since the electrodes of the electric furnace are made of graphite and the furnace is in a reducing atmosphere, the graphite reacts with the iron oxide to generate molten iron in the furnace, so the molten iron of the electric furnace needs to be discharged regularly.

[0042] Combination Figure 3 As shown, the multi-layer refractory insulation structure of the electric furnace bottom also includes a high-aluminum brick layer 24 and a thermal insulation refractory brick layer 25 arranged below the working layer 23 from top to bottom. The thickness of the working layer 23 is 540-600 mm, the thickness of the high-aluminum brick is 360-440 mm, and the thickness of the thermal insulation refractory brick layer 25 is 180-220 mm. Among them, the main functions of the high-aluminum brick layer 24 and the thermal insulation refractory brick layer 25 are support and ventilation. The working layer 23 paved with magnesium-calcium ramming material, as the main anti-corrosion working layer 23, is designed as an arc-shaped structure with a concave middle, which is convenient for collecting and storing molten iron.

[0043] In a specific embodiment, the chemical composition of the magnesium-calcium ramming material of the working layer 23 is as follows by mass percentage: MgO 80-90%, CaO 8-12%, Fe2O3 3-4%; the refractory temperature of the working layer 23 is 1500-1600°C, and the density is 2.3-2.5 g / cm 3 In the high-alumina brick layer 24, the mass percentage of Al2O3 is 50-60%, and the mass percentage of Fe2O3 is 1-1.5%; the density of the high-alumina brick layer 24 is 2.3-2.7 g / cm 3 , cold compression strength ≥ 78MPa. The chemical composition of the thermal insulation refractory brick layer 25 is calculated by mass percentage: Al2O3 40-45%, SiO2 50-55%, Fe2O3 1-1.5%; the density of the thermal insulation refractory brick layer 25 is 0.75-0.8g / cm 3 , cold pressing strength ≥1.7MPa.

[0044] In a specific embodiment, the arc radius of the arc structure is 40-46 m, and the arc center angle is 6-7 degrees.

[0045] S2, before starting the electric furnace, iron metal is first put into the furnace to form a molten iron layer on the working layer of the furnace bottom. Later, during the preparation of the rock wool melt, the molten iron is regularly discharged through the iron outlet on the side of the furnace bottom.

[0046] This step is mainly to form a molten iron layer. Before the electric furnace is started, iron metal is first added into the furnace to form a molten iron layer 22 on the furnace bottom working layer 23. Then, during the preparation of the rock wool melt, molten iron is regularly discharged through the iron outlet 26 on the side of the furnace bottom. During the formation of the above molten iron layer 22, the amount of iron metal added is 8 to 12 tons.

[0047] In the preparation process of rock wool melt, the tempering material used contains iron oxide, and the mass percentage of iron oxide is 8-20%. Since the electric furnace electrode adopts graphite electrode and the furnace is in a reducing atmosphere, graphite and iron oxide undergo a reduction reaction, and molten iron is also produced in the furnace. The molten iron of the electric furnace needs to be discharged regularly; therefore, the height of the molten iron layer in the furnace is regularly detected. When the molten iron layer reaches the upper limit height of the tapping port 26, the molten iron is discharged through the tapping port 26 at the bottom of the furnace wall to ensure that the molten iron layer is within the safety control range. The mass percentage composition of the rock wool melt is: SiO2 40-45%, Al2O3 12-15%, MgO 5-7%, CaO 26-30%, iron oxide 4-6%, and the acidity coefficient of the finally obtained rock wool melt is ≥1.6.

[0048] The design principle of the present invention is: since there are many oxides in the chemical composition of the rock wool melt, such as SiO2, Al2O3, MgO, CaO, FeO, Fe2O3, etc., and the polar center circle area corresponding to the lower end of the electrode is the high temperature area in the furnace (see Figure 4 ), higher requirements are placed on the corrosion resistance of furnace bottom refractory materials. Conventional refractory materials cannot simultaneously meet the requirements of both high temperature resistance and chemical corrosion resistance. Therefore, using the molten iron layer 22 to isolate the rock wool melt from the furnace bottom working layer 23 refractory materials is a very effective method for protecting refractory materials.

[0049] In the design method of the present invention, magnesium-calcium ramming material is selected as the furnace bottom working layer 23, and a molten iron layer 22 is added before starting the furnace to isolate the rock wool melt from the working layer 23 refractory materials, which can effectively protect the working layer 23 refractory materials and ensure the service life of the electric furnace bottom refractory materials for more than 2 years. When the amount of molten iron in the furnace increases to a certain amount, the iron outlet 26 is opened to discharge iron to ensure that the molten iron in the furnace is within a reasonable range.

[0050] The long-life hot molten slag electric furnace bottom for preparing rock wool is prepared by the above-mentioned design method of refractory materials for the electric furnace bottom for preparing rock wool. The electric furnace bottom adopts a multi-layer refractory insulation structure, which includes a working layer 23, a high-alumina brick layer 24 and an insulating refractory brick layer 25 arranged from top to bottom; the working layer 23 is paved with magnesium-calcium ramming material, and the top of the working layer 23 is an arc-shaped structure with a concave middle; the electric furnace bottom also includes a molten iron layer 22 formed on the working layer 23 by adding iron metal into the furnace before the electric furnace is started.

[0051] The present invention also provides an electric furnace for preparing rock wool with long-life hot molten slag, comprising the above-mentioned bottom of the electric furnace for preparing rock wool with long-life hot molten slag.

[0052] Example

[0053] refer to Figure 3 As shown, the design method of the bottom refractory material of an electric furnace for preparing rock wool with long-life hot molten slag in this embodiment is as follows:

[0054] (1) Electric furnace equipment and its parameters;

[0055] Specifications of the long-life hot molten slag electric furnace for preparing rock wool: outer diameter 4700mm, height 3295mm, electrode circle diameter 1386mm, graphite electrode diameter 300mm;

[0056] A slag outlet 21 is provided on the furnace wall 20 of an electric furnace for preparing rock wool with long-life hot molten slag; the bottom of the electric furnace adopts a multi-layer refractory insulation structure, which includes a working layer 23, a high-alumina brick layer 24 and an insulating refractory brick layer 25 arranged from top to bottom. The specific parameters are shown in Table 1. The working layer 24 is paved with magnesium-calcium ramming material, and the top of the working layer 24 is an arc structure with a concave middle; the arc structure corresponds to an arc radius of 40m, and the arc central angle is 6.7 degrees; a tapping port 26 is also provided at the lower part of the furnace wall.

[0057] Table 1 Parameters of refractory laying at the bottom of electric furnace

[0058]

[0059] (2) Formation of molten iron layer and preparation of rock wool

[0060] Before starting the electric furnace, 8.5 tons of iron metal are first put into the furnace on the furnace bottom working layer 23, and then 10 tons of slag are added to power on the furnace. After all the molten metal is melted, a molten iron layer 22 will be formed on the furnace bottom working layer 23, and then hot molten slag and tempering material are added to prepare rock wool melt, wherein the iron oxide content of the tempering material is 8-20%; during the preparation of the rock wool melt, molten iron is regularly discharged through the iron outlet 26 at the lower part of the furnace wall. When the amount of molten iron in the furnace exceeds the upper height of the slag outlet, the iron outlet is opened to discharge the molten iron to ensure that the molten iron layer in the furnace does not exceed the upper limit height of the iron outlet, and finally a rock wool melt with an acidity coefficient ≥1.6 is obtained, and its composition is shown in Table 2; then the subsequent rock wool preparation process is entered.

[0061] Table 2 Composition of rock wool melt

[0062] chemical composition <![CDATA[SiO2]]> <![CDATA[AL2O3]]> MgO CaO <![CDATA[Fe2O3+FeO]]> scope% 40～45 12～15 5～7 26～30 4～6

[0063] During the above process, the operation of the electric furnace is as follows: the furnace bottom temperature monitoring data shows that the furnace bottom temperature is stable at 360-370°C. It can be seen that the erosion of the refractory material at the bottom of the electric furnace is small, safe and stable, and the service life is more than 2 years.

[0064] In summary, the design method of the long-life hot molten slag electric furnace bottom refractory material for preparing rock wool, the furnace bottom, and the electric furnace of the present invention can greatly improve the service life of the electric furnace bottom refractory material, reduce the production line downtime due to the maintenance of the electric furnace refractory material, and thus improve the operation rate of the hot molten slag rock wool production line.

[0065] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A design method for electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag, characterized in that: The following steps are involved: S1, using a multi-layer refractory insulation structure to pave the bottom of the electric furnace, the top of the multi-layer refractory insulation structure uses a working layer paved with magnesium-calcium ramming material, and the top of the working layer is designed to be an arc-shaped structure with a concave middle; S2, before starting the electric furnace, iron metal is first put into the furnace to form a molten iron layer on the working layer at the bottom of the furnace. Later, during the preparation of the rock wool melt, the molten iron is regularly discharged through the iron outlet at the bottom of the furnace wall.

2. The design method of the electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag according to claim 1 is characterized by: In the step S1, the multi-layer refractory insulation structure of the electric furnace bottom further includes a high-alumina brick layer and a thermal insulation refractory brick layer arranged below the working layer from top to bottom; The thickness of the working layer is 540-600 mm, the thickness of the high-alumina brick is 360-440 mm, and the thickness of the thermal insulation refractory brick layer is 180-220 mm.

3. The design method of the electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag according to claim 2 is characterized by: The chemical composition of the magnesium-calcium ramming material of the working layer is as follows by mass percentage: MgO 80-90%, CaO 8-12%, Fe2O3 3-4%; In the high-alumina brick layer, the mass percentage content of Al2O3 is 50-60%, and the mass percentage content of Fe2O3 is 1-1.5%; The chemical composition of the thermal insulation refractory brick layer is calculated by mass percentage as follows: Al2O3 40-45%, SiO2 50-55%, and Fe2O3 1-1.5%.

4. The design method of the electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag according to claim 2 is characterized by: The refractory temperature of the working layer is 1500-1600°C and the density is 2.3-2.5 g / cm 3 ; The density of the high alumina brick layer is 2.3-2.7 g / cm 3 , cold pressing strength ≥78MPa; The density of the thermal insulation refractory brick layer is 0.75-0.8 g / cm 3 , cold pressing strength ≥1.7MPa.

5. The design method of the electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag according to claim 1 is characterized by: The arc radius of the arc structure is 40-46 m, and the arc center angle is 6-7 degrees.

6. The design method of the electric furnace bottom refractory material for preparing rock wool with long-life hot molten slag according to claim 1 is characterized by: In step S2: The input amount of the iron metal is 8 to 12 tons; During the rock wool melt preparation process, the height of the molten iron layer in the furnace is regularly checked. When the amount of molten iron exceeds the upper limit height of the tap hole, the molten iron is discharged through the tap hole at the lower part of the furnace wall.

7. The design method of the refractory material for the bottom of an electric furnace for preparing rock wool from long-life hot molten slag according to claim 1, characterized in that: In step S2: In the process of preparing the rock wool melt, the quenching and tempering material used contains iron oxide, and the mass percentage of the iron oxide is 8-20%; The mass percentage components of the rock wool melt are: SiO2 40-45%, Al2O3 12-15%, MgO 5-7%, CaO2 6-30%, and iron oxide 4-6%.

8. A long-life hot molten slag electric furnace bottom for preparing rock wool prepared by the design method of the long-life hot molten slag electric furnace bottom refractory for preparing rock wool according to any one of claims 1 to 7, characterized in that: The bottom of the electric furnace adopts a multi-layer refractory insulation structure, which includes a working layer, a high-alumina brick layer and a thermal insulation refractory brick layer arranged from top to bottom; The working layer is paved with magnesium-calcium ramming material, and the top of the working layer is an arc-shaped structure with a concave middle; The bottom of the electric furnace also includes a molten iron layer formed on the working layer by throwing iron metal into the furnace before the electric furnace is started.

9. A long-life electric furnace for preparing rock wool using hot molten slag, characterized in that: It comprises the bottom of an electric furnace for preparing rock wool with the long-life hot molten slag as described in claim 8.

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