1. The magnesium hot-melt adhesive is characterized by comprising the following raw materials in parts by mass: 60-80 parts of large-particle magnesia, 7-8 parts of asphalt, 3-4 parts of organic solvent and 8-30 parts of small-particle magnesia.

2. The process of claim 1, comprising the steps of,

1) crushing the dead burnt magnesia into large-particle magnesia and small-particle magnesia;

2) dissolving asphalt in an organic solvent;

3) mulling the large-particle magnesia and the asphalt obtained in the step 2) to fully wrap the asphalt on the surface of the large-particle magnesia;

4) then adding small-particle magnesite for mulling, and conveying the mixture to a ball press for pressing into balls.

3. The process of claim 1, wherein the magnesia content of the magnesite is greater than 90%, the silica content is less than 3.5%, the calcium oxide content is less than 5%, and the bulk density is greater than 3.4g/cm³。

4. The process according to claim 1, wherein the particle size of the large particles in step 1) is 0-12mm, and the particle size of the small particles is 0-74 μm.

5. The process of claim 1, wherein the organic solvent in step 2) is one or more of gasoline, xylene, n-hexane, and carbon tetrachloride.

6. The process of claim 1, wherein the asphalt of step 2) has a softening point of 80-90 ℃, an ash content of less than 0.5, and a coking value of more than 48%.

7. The process according to claim 1, wherein the mixing time in step 3) is 6 min.

8. The process according to claim 1, wherein the mixing time in step 4) is 6 min.

9. The process according to claim 1, wherein the diameter of the spheres of step 4) is 30-40 mm.

Technical Field

In the production of converter steelmaking, the erosion and damage speed of a slag line of refractory lining bricks, a large-surface part for loading and tapping, a slag line and a furnace door part in electric furnace steelmaking is far faster than that of a furnace wall, a molten pool and a furnace bottom part, and the repair of the damaged part is essential in order to ensure that the overall service time of the lining bricks is consistent and the overall service life of the lining bricks is prolonged.

The magnesium large-surface repairing materials adopted at present are mainly two, namely a magnesium bulk large-surface self-flowing material and a magnesium massive hot-patching material.

The self-flowing material is prepared by pulverizing magnesite into 0-5mm or 0-8mm, adding 200 mesh fine powder, grading by three-stage or four-stage, adding medium-temperature modified asphalt, humectant, water reducer, etc., mixing, and packaging. However, this product has significant disadvantages: the sintering time is long due to the fact that the sintering material is a bulk material, gaps between the material and the material are small, and the sintering material is airtight; (II) limited stacking thickness; the spreading performance is poor, and after heating, the materials cannot be completely wrapped by the bonding agent, and part of granular materials are exposed on the surface, so that the material is not resistant to scouring and has a large loss ratio.

The magnesia massive hot patching material is prepared by heating magnesia, heating asphalt to melt, mixing with magnesia, adding sintering promoter, mixing, stirring, cooling, and crushing into blocks of 0-100 mm. The product has the disadvantages of poor fluidity and poor spreadability in use. Most importantly, in the production process, as magnesia needs to be heated, asphalt is partially carbonized after being heated, a large amount of smoke is generated, and the production process does not meet the requirement of environmental protection. Environmental protection departments in various regions have prohibited the production of products by the process.

Disclosure of Invention

The invention aims to overcome the defects of non-environment-friendly production process, long sintering time, poor fluidity, large material loss and the like existing in the conventional magnesium hot-patch material in use, and provides a preparation process of the magnesium hot-patch material, which has the advantages of environment-friendly process, long service life and low cost.

In order to achieve the purpose, the technical method adopted by the invention is as follows: a magnesium hot-melt adhesive comprises the following raw materials in parts by weight: 80-85 parts of large-particle magnesia, 5-10 parts of asphalt, 1-5 parts of organic solvent and 5-10 parts of small-particle magnesia.

The preparation process of the magnesium hot-melt adhesive is characterized by comprising the following steps of,

1) crushing the dead burnt magnesia into large-particle magnesia and small-particle magnesia;

2) dissolving asphalt in an organic solvent;

3) mulling the large-particle magnesia and the asphalt obtained in the step 2) to fully wrap the asphalt on the surface of the large-particle magnesia;

4) then adding small-particle magnesite for mulling, and conveying the mixture to a ball press for pressing into balls.

In the preparation process of the magnesia hot-patch material, the content of magnesia in magnesia is more than 90%, the content of silica is less than 3.5%, the content of calcium oxide is less than 5%, and the bulk density is more than 3.4.

In the preparation process of the magnesium hot-melt adhesive, the particle size of the large particles in the step 1) is 0-12mm, and the particle size of the small particles is 0-74 μm.

In the preparation process of the magnesium hot-melt adhesive, the organic solvent in the step 2) is one or more of gasoline, xylene, n-hexane and carbon tetrachloride.

In the preparation process of the magnesium hot-patching material, the softening point of the asphalt in the step 2) is 80-90 ℃, the ash content is less than 0.5, and the coking value is more than 48%.

In the preparation process of the magnesium hot-melt adhesive, the mixing time in the step 3) is 6 min.

In the preparation process of the magnesium hot-melt adhesive, the mixing time in the step 4) is 6 min.

In the preparation process of the magnesium hot-melt adhesive, the diameter of the ball in the step 4) is 30-40 mm.

The invention has the following beneficial effects: the product is uniform spherical, and can be quickly paved on the damaged part after being thrown on the repaired part and swayed by a rocking furnace. And (II) the sintering is fast. Because the asphalt is not heated and not carbonized, and is uniformly coated on the surface of the particles. The materials are uniform spheres, and the spheres have larger gaps and good air permeability, so the combustion is fast, the melting is uniform, and the sintering time is short; and (III) scouring resistance. Because the binder asphalt is dispersed evenly in a heating state and can completely wrap the material, the material has no naked particles after being sintered, and has smooth surface and scouring resistance. And (IV) the cost is reduced. The asphalt is not heated and carbonized, so that the addition amount of the asphalt and fine powder can be reduced, the product is pressed into a spherical solid, no dust is generated in the feeding process, wetting agents, paraffin and other additives can not be added, and the cost of the product can be greatly reduced.

Detailed Description

Dissolving asphalt in asphalt dissolving agent, and crushing the electrically smelted or dead burnt magnesia containing magnesia in over 90% into 0-12mm size grains and 200 mesh size powder. Firstly, adding magnesia particles of 0-12mm into the started mixing roller by 80 parts by mass, then adding 12 parts by mass of dissolved asphalt, fully stirring and mixing for 6 minutes to ensure that the asphalt is fully wrapped on the surface of the material, finally adding 200-mesh magnesia fine powder by 8 parts by mass, stirring and mixing for 6 minutes to ensure that the 200-mesh fine powder is wrapped on the surface of the material, finally conveying the mixed material into a ball press by a conveyer belt, and pressing the material into spherical objects of 30mm or 40mm by a machine to prepare the finished product. Because the product does not need to be heated in the production process, no smoke dust exists, and the environment-friendly requirement is met. And because the product is spherical solid, when the product is used, the material is put in the damaged part, the material can be automatically spread at the damaged part, then the bonding agent in the material can be quickly melted through the temperature of the steel furnace, and the material is tightly bonded at the damaged part.

Example 1

The raw material technical requirements are that the content of magnesium oxide in the magnesia is more than 90%, the content of silicon dioxide is less than 3.5, the content of calcium oxide is less than 5, and the bulk density is more than 3.4. The particle size is 0-12mm, the fine powder mesh number is more than 200 meshes, and the passing rate is more than 90%. (the medium temperature asphalt has a penetration temperature of 25 ℃ (0.1mm) of 60-80%, a ductility of 10 ℃ (cm) of more than 20, a dynamic viscosity (mm/s) of 30-40%, a softening point of 80-90 ℃ of the asphalt, ash content of less than 0.5 and a coking value of more than 48 percent).

The preparation method comprises the steps of firstly putting 80 parts by mass of magnesia particles of 0-12mm into a stirring mixing roller, putting 8 parts by mass of asphalt into a container, keeping the temperature of the asphalt at 50 ℃, adding 4 parts by mass of gasoline into the stirring mixing roller, uniformly stirring the mixture, adding the mixture into the mixing roller, stirring the mixture for 6 minutes, adding 8 parts by mass of 200-mesh fine powder into the mixing roller, stirring the mixture for 6 minutes, and inputting the material into a ball press. Finally pressing into spherical solid of 30-40mm to obtain the final product.

In order to prevent the materials from being bonded with the roller of the ball press in the process of pressing the balls, a small amount of light-burned magnesia powder or lime powder is scattered on the roller by a small hopper or water drops are uniformly dripped on the roller in the production process, and then the materials are extruded into balls.

Example 2

The raw material technical requirement is that the content of magnesium oxide in the magnesia is more than 90%, the content of silicon dioxide is less than 3.5, the content of calcium oxide is less than 5, and the bulk density is more than 3.4. The particle size is 0-12mm, the fine powder mesh number is more than 200 meshes, and the passing rate is more than 90%. (the medium temperature asphalt has a penetration temperature of 25 ℃ (0.1mm) of 60-80%, a ductility of 10 ℃ (cm) of more than 20, a dynamic viscosity (mm/s) of 30-40%, a softening point of 80-90 ℃ of the asphalt, ash content of less than 0.5 and a coking value of more than 48 percent).

The preparation method comprises the steps of firstly putting 0-12mm magnesia particles into a stirring mixing roller according to 60 parts by mass, putting 7 parts by mass of asphalt into a container, keeping the temperature of the asphalt at 50 ℃, adding 3 parts by mass of gasoline into the stirring mixing roller, uniformly stirring the mixture, adding the mixture into the mixing roller, stirring the mixture for 6 minutes, adding 200-mesh fine powder into the mixing roller according to 30 parts by mass, stirring the mixture for 6 minutes, and inputting the material into a ball press. Finally pressing into spherical solid of 30-40mm to obtain the final product.

In order to prevent the materials from being bonded with the roller of the ball press in the process of pressing the balls, a small amount of light-burned magnesia powder or lime powder is scattered on the roller by a small hopper or water drops are uniformly dripped on the roller in the production process, and then the materials are extruded into balls.

When the repair material is used, the converter is firstly shaken to be horizontal, the magnesium hot repair material hopper is put on the large surface of the converter to be repaired, the steel-making furnace is moved, the magnesium hot repair material is spread, after the magnesium hot repair material hopper is spread, a part where the magnesium hot repair material is not spread is provided, the material can be added by a hopper or a small package of magnesium hot repair material in a hand-throwing mode until the part to be repaired is paved with the repair material. And then sintering for 10-15 minutes by using the furnace temperature of the steel furnace, and after the bonding agent asphalt in the repairing material is completely solidified, can be lifted up, and the steel-making production is started. When the furnace lining brick is used in the later period and the position needing to be repaired is larger, the whole ton bag filled with repairing burden can be directly put in the position needing to be repaired, and other repairing burdens and sintering methods are the same as the above.