阅读说明：本技术 半轻质钢包永久层浇注料及其制备钢包永久层的方法 (Semi-light ladle permanent layer castable and method for preparing ladle permanent layer by using same ) 是由 姚亚双 孙枫 雷中兴 王志强 童健 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种半轻质钢包永久层浇注料及其制备钢包永久层的方法,属于炼钢钢包炉技术领域。它由如下重量百分比的各成分组成：高铝矾土熟料10～35％；天然烧结莫来石10～30％；轻质莫来石10～30％；莫来石球10～20％；铝酸钙水泥2～6％；氧化铝微粉2～8％；硅微粉3～6％；不锈钢纤维0.5～3％；聚丙烯纤维0.01～0.04％；减水剂0.1～0.5％。由该浇注料制成的永久层不仅具备隔热保温性能,同时,在承受高温钢水侵蚀作用下,力学强度较高,能有效防止钢壳形变以及其带来的相关安全风险。(The invention discloses a semi-light ladle permanent layer castable and a method for preparing a ladle permanent layer by using the same, and belongs to the technical field of steel-making ladle furnaces. The paint comprises the following components in percentage by weight: 10-35% of bauxite chamotte; 10-30% of natural sintered mullite; 10-30% of light mullite; 10-20% of mullite spheres; 2-6% of calcium aluminate cement; 2-8% of alumina micro powder; 3-6% of silicon micropowder; 0.5-3% of stainless steel fiber; 0.01-0.04% of polypropylene fiber; 0.1-0.5% of water reducing agent. The permanent layer made of the castable not only has heat insulation performance, but also has higher mechanical strength under the action of bearing high-temperature molten steel erosion, and can effectively prevent the deformation of the steel shell and related safety risks brought by the deformation.)

1. A semi-light ladle permanent layer castable comprises the following components in percentage by weight:

the light mullite comprises two grain size components: the granularity is not less than 5mm and not more than 8mm, the granularity is not less than 3mm and not more than 5mm, and the mass percentages of the granularity components are respectively 40-60% and 60-40%;

the mullite spheres also include two grain size components: the granularity is not less than 3mm and not more than 5mm, the granularity is not less than 1mm and not more than 3mm, and the mass percentages of the granularity components are respectively 40-55% and 60-45%;

the mass percentage content of alumina in the calcium aluminate cement is more than or equal to 70 percent, and the granularity of the alumina in the calcium aluminate cement is less than or equal to 0.088 mm;

the mass percentage content of the silicon dioxide in the silicon micro powder is more than or equal to 92 percent, and the granularity of the silicon dioxide is less than or equal to 0.088 mm.

2. The semi-lightweight ladle permanent layer castable according to claim 1, wherein: the melting point of the stainless steel fiber is 1425-1510 ℃, and the length of the stainless steel fiber is 20-30 mm.

3. The semi-lightweight ladle permanent layer castable according to claim 2, wherein: the melting point of the stainless steel fiber is 1480-1500 ℃, and the using amount of the stainless steel fiber is 2.5-3%.

4. A semi-lightweight ladle permanent layer castable as claimed in claim 1, 2 or 3, wherein: the content of the aluminum oxide in the natural sintered mullite is more than or equal to 68 percent; the particle size is not less than 1mm and not more than 3mm, the particle size is not less than 0.088mm and not more than 1mm, and the mass percentages of the particle size components are respectively as follows: 10-40% and 90-60%.

5. A semi-lightweight ladle permanent layer castable as claimed in claim 1, 2 or 3, wherein: the mass percentage content of the alumina in the bauxite chamotte is more than or equal to 85 percent; the particle size is not less than 8mm and not more than 12mm, and the particle size is not more than 0.088mm, wherein the mass percentages of the particle size components are respectively as follows: 30-45% and 70-55%.

6. A semi-lightweight ladle permanent layer castable as claimed in claim 1, 2 or 3, wherein: the castable comprises the following components in percentage by weight:

wherein the light mulliteThe content of the medium alumina is more than or equal to 65 percent by weight, and the volume density is 1.1-1.2 g/cm³；

The content of aluminum oxide in the mullite spheres is more than or equal to 68 percent by weight, and the volume density is 1.3-1.5 g/cm³。

7. The semi-lightweight ladle permanent layer castable according to claim 6, wherein: the castable comprises the following components in percentage by weight:

8. a method for preparing a permanent layer of a steel ladle by using the castable according to claim 1 comprises the steps of adding water into the castable according to the formula, stirring and fully mixing the castable, pouring the castable into the bottom of the steel ladle, naturally curing the castable to form a permanent layer of the bottom of the steel ladle with the thickness of 150-200 mm, and forming a permanent layer of the wall of the steel ladle with the thickness of 80-120 mm on the side wall of the steel ladle by using a steel ladle moulding bed.

9. A method of using a castable material according to claim 8 in the preparation of a permanent layer of a ladle, characterised in that: the water addition amount is 7.5-8.5% of the mass of the castable.

10. A method of using a castable material according to claim 8 in the preparation of a permanent layer of a ladle, characterised in that: the natural curing condition is curing at room temperature for 12-24 hours, and then preserving heat at the temperature of 100-110 ℃ for 12-24 hours.

Technical Field

The invention relates to a ladle castable, belongs to the technical field of steel-making ladle furnaces, and particularly relates to a semi-light ladle permanent layer castable and a method for preparing a ladle permanent layer by using the same.

Background

The domestic traditional smelting ladle furnace lining structure is mainly divided into two layers, namely a permanent layer and a working layer; the permanent layer mainly comprises high-alumina castable or high-alumina bricks, the working layer mainly comprises magnesia-alumina-carbon bricks, magnesia-carbon bricks or carbon-free bricks, and the temperature of the steel ladle shell is 250-380 ℃. The permanent layer is usually not in direct contact with molten steel, the thickness is about 80-150 mm, the main function of the permanent layer is heat insulation and heat preservation, the influence on the quality of cast steel caused by too fast temperature drop of a ladle is prevented, in special conditions, such as LF, RH and other external refining processes, when the smelting temperature is higher, scouring and erosion are more serious and other severe using conditions are adopted, the working layer can be caused to be in direct contact with the molten steel due to accidental damage, the erosion of a slag line part is the most serious, the probability of steel leakage through the ladle is the greatest, and the permanent layer is required to bear the erosion and scouring of the molten steel for more than 2 times. Meanwhile, the steel ladle shell has overhigh temperature, and the steel shell can deform in the later period; the thickness of the permanent layer is uneven, and a great safety risk is caused in the using process. And light bricks, fiberboards, nano heat insulation boards or light low-heat-conductivity casting materials are used as the permanent layer linings in part of steel mills. The technologies can reduce the temperature of the ladle shell to 220-250 ℃, make certain progress, and still have the problem that the safety, the heat insulation and the service life cannot be considered in a synergistic way.

Disclosure of Invention

In order to solve the technical problems, the invention discloses a semi-light ladle permanent layer castable, wherein a permanent layer made of the castable has heat insulation performance, has higher mechanical strength under the action of bearing high-temperature molten steel erosion, and can effectively prevent the deformation of a steel shell and related safety risks brought by the deformation.

In order to realize the aim, the invention discloses a semi-light ladle permanent layer castable which comprises the following components in percentage by weight:

the light mullite comprises two grain size components: the granularity is not less than 5mm and not more than 8mm, the granularity is not less than 3mm and not more than 5mm, and the mass percentages of the granularity components are respectively 40-60% and 60-40%; if the light mullite with the granularity less than 3mm is added, the smaller the granularity of the light mullite with the same weight is, the larger the specific surface area is, more water needs to be added, and the water absorption capacity of the castable is increased, and the strength is obviously reduced. Similarly, if the light mullite with the granularity of more than 8mm is added, the overall strength of the castable is inevitably influenced.

The mullite spheres also include two grain size components: the granularity is not less than 3mm and not more than 5mm, the granularity is not less than 1mm and not more than 3mm, and the mass percentages of the granularity components are respectively 40-55% and 60-45%; if mullite spheres with the granularity of more than 5mm are added to the castable, the mullite spheres are easy to float on the surface when the castable is molded, so that the distribution is concentrated, the particle size distribution is seriously segregated, and the volume density and the strength of the castable can be obviously reduced by adding the mullite spheres with the granularity of less than 1 mm.

The mass percentage content of alumina in the calcium aluminate cement is more than or equal to 70 percent, and the granularity of the alumina in the calcium aluminate cement is less than or equal to 0.088mm, wherein the granularity does not include zero, and the mass percentage content of the alumina in the calcium aluminate cement is not more than 100 percent;

the mass percentage content of the silicon dioxide in the silicon micro powder is more than or equal to 92 percent, the granularity of the silicon dioxide is less than or equal to 0.088mm, wherein the granularity does not include zero, and the mass percentage content of the silicon dioxide in the silicon micro powder is not more than 100 percent.

Furthermore, the melting point of the stainless steel fiber is 1425-1510 ℃, and the length of the stainless steel fiber is 20-30 mm.

Furthermore, the melting point of the stainless steel fiber is 1480-1500 ℃, and the using amount of the stainless steel fiber is 2.5-3%.

Further, the total mass percentage content of the light mullite and the mullite spheres is 30-40%.

Further, the mass ratio of the mixture of the light mullite and the mullite spheres to the stainless steel fibers is (10-80): 1.

Furthermore, the mass ratio of the calcium aluminate cement to the alumina micro powder to the silica micro powder is (2-5) to (3-8) to (3-6).

Further, the content of alumina in the natural sintered mullite is more than or equal to 68 percent; the particle size is not less than 1mm and not more than 3mm, the particle size is not less than 0.088mm and not more than 1mm, and the mass percentages of the particle size components are respectively as follows: 10-40% and 90-60%, wherein the content of aluminum oxide in the natural sintered mullite is not more than 100%.

Further, the alumina content in the bauxite chamotte is more than or equal to 85 percent; the particle size is not less than 8mm and not more than 12mm, and the particle size is not more than 0.088mm, wherein the mass percentages of the particle size components are respectively as follows: 30-45% and 70-55%, wherein the content of alumina in the bauxite chamotte is not more than 100%, and the granularity of the bauxite chamotte is matched with the granularity of the light mullite and the granularity of the mullite spherulite so as to ensure the granularity uniformity of the final castable.

Further, the water reducing agent is at least one of sodium tripolyphosphate or sodium hexametaphosphate.

Further, the castable comprises the following components in percentage by weight:

wherein the content of aluminum oxide in the light mullite is more than or equal to 65 percent by weight, and the volume density is 1.1-1.2 g/cm³(ii) a Wherein, the content of the aluminum oxide in the light mullite is not more than 100 percent.

The content of aluminum oxide in the mullite spheres is more than or equal to 68 percent by weight, and the volume density is 1.3-1.5 g/cm³Wherein, the content of the aluminum oxide in the mullite ball is not more than 100 percent.

Further, the castable comprises the following components in percentage by weight:

the principle of selecting the raw materials is as follows:

1. the light mullite and the mullite ball have low heat conductivity coefficient, and the heat conductivity of the target castable is reduced by adding the two components, but the two components have low strength, which is not beneficial to ensuring the mechanical strength of the casting material, the stainless steel fiber has high electric conductivity and heat conductivity, the invention firstly selects the light mullite and the mullite balls to be compounded to obtain the mullite raw material with evenly distributed granularity, and then the mullite raw material is filled in the stainless steel fiber gaps which are mutually wound and have a certain length, because the component content of the mullite raw material is far larger than the content of the stainless steel fiber, the electric and heat conductivity of the stainless steel fiber is weakened to a certain extent, but simultaneously, the length of the stainless steel fiber is 20-30 mm, the connection effect of each granularity component among the mullite raw materials can be enhanced, thereby being beneficial to improving the mechanical strength of the mullite raw materials.

In addition, the light mullite includes two grain size components: the granularity is not less than 5mm and not more than 8mm, the granularity is not less than 3mm and not more than 5mm, and the mass percentages of the granularity components are respectively 40-60% and 40-60%; mullite spheres also include two grain size components: the granularity is not less than 3mm and not more than 5mm, the granularity is not less than 1mm and not more than 3mm, and the mass percentages of the granularity components are respectively 40-55% and 45-60%; the average grain size of the light mullite is slightly higher than that of the mullite spheres, and the light mullite and the mullite spheres play a synergistic role to ensure the safe use and longer service life of the castable.

2. The calcium aluminate cement and the alumina micropowder can generate different calcium aluminate products in the using process of the castable, for example, calcium aluminate cement is firstly hydrated to generate hexa-diaspore in the application, and the calcium aluminate cement and the alumina micropowder gradually generate C in the using process₁₂A₇、CA₆The calcium aluminate product is beneficial to increasing the strength and the slag corrosion resistance of the castable; the alumina micro powder and the silica micro powder can generate mullite in the use process of the castable, so that the volume stability and the bonding strength of the castable are improved.

3. The polypropylene fiber is beneficial to reducing the curing and drying time after the castable is constructed, improving the volume stability during baking or using and preventing bursting.

4. The bauxite chamotte comprises two components with the granularity of more than or equal to 8mm and less than or equal to 12mm and the granularity of less than or equal to 0.088mm, and the components with the granularity are matched with each other to ensure the construction performance and the service performance of the castable.

5. The natural sintered mullite has high volume density, and is cooperatively compounded with the light mullite and the mullite spheres to ensure the heat insulation performance of the castable.

In order to better achieve the technical purpose of the invention, the invention also discloses a method for preparing the permanent layer of the steel ladle by using the castable, which comprises the steps of adding water into the castable according to the formula, stirring and fully mixing the water and the castable uniformly, pouring the castable into the bottom of the steel ladle, naturally curing the castable to form a permanent layer of the ladle bottom with the thickness of 150-200 mm, and forming a permanent layer of the ladle wall with the thickness of 80-120 mm on the side wall of the steel ladle by using a steel ladle moulding bed.

Furthermore, the water addition amount is 7.5-8.5% of the mass of the castable. Wherein, the strength of the castable can be obviously reduced when the water adding amount is too high, and further the use effect is influenced, and the castable is dry, the aggregate and powder coating performance is not good, and the loose condition is caused when the water adding amount is too low.

Further, the natural curing condition is curing at room temperature for 12-24 hours, and then preserving heat at the temperature of 100-110 ℃ for 12-24 hours. The curing time is less than 12 hours, so that the hydration time of the binding agent is insufficient, and the strength of the castable is influenced; the maintenance time is more than 24 hours, which affects the construction progress of the site. When the baking temperature is higher than 110 ℃, the castable can be rapidly dehydrated to generate cracks; when the baking temperature is less than 100 ℃, the moisture in the casting material can not be timely and effectively discharged, and the phenomena of cracking and the like are easily caused during use.

The beneficial effects of the invention are mainly embodied as follows:

the invention discloses a semi-light ladle permanent layer castable, wherein a ladle permanent layer prepared from the castable has good heat insulation and heat preservation properties, has better mechanical strength, can bear erosion and scouring of molten steel, and has longer service life than the conventional permanent layer.

Detailed Description

The invention discloses a semi-light ladle permanent layer castable which comprises the following components in percentage by weight:

the light mullite comprises two grain size components: the granularity is not less than 5mm and not more than 8mm, the granularity is not less than 3mm and not more than 5mm, and the mass percentages of the granularity components are respectively 40-60% and 40-60%; the content of aluminum oxide in the light mullite is more than or equal to 65 percent by weight, and the volume density is 1.1-1.2 g/cm³；

The mullite spheres also include two grain size components: the granularity is not less than 3mm and not more than 5mm, the granularity is not less than 1mm and not more than 3mm, and the mass percentages of the granularity components are respectively 40-55% and 45-60%; the content of aluminum oxide in the mullite spheres is more than or equal to 68 percent by weight, and the volume density is 1.3-1.5 g/cm³。

The mass percentage content of alumina in the calcium aluminate cement is more than or equal to 70 percent, and the granularity of the alumina in the calcium aluminate cement is less than or equal to 0.088 mm;

the mass percentage content of the silicon dioxide in the silicon micro powder is more than or equal to 92 percent, and the granularity of the silicon dioxide is less than or equal to 0.088 mm.

The content of the aluminum oxide in the natural sintered mullite is more than or equal to 68 percent; the particle size is not less than 1mm and not more than 3mm, the particle size is not less than 0.088mm and not more than 1mm, and the mass percentages of the particle size components are respectively as follows: 10-40% and 60-90%.

The mass percentage content of the alumina in the bauxite chamotte is more than or equal to 85 percent; the particle size is not less than 8mm and not more than 12mm, and the particle size is not more than 0.088mm, wherein the mass percentages of the particle size components are respectively as follows: 30-45% and 55-70%.

The melting point of the stainless steel fiber is 1425-1510 ℃, and the length of the stainless steel fiber is 20-30 mm.

The water reducing agent is at least one of sodium tripolyphosphate or sodium hexametaphosphate.

Further, the total mass percentage content of the light mullite and the mullite spheres is 30-40%.

Further, the mass ratio of the mixture of the light mullite and the mullite spheres to the stainless steel fibers is (10-80): 1.

Furthermore, the mass ratio of the calcium aluminate cement to the alumina micro powder to the silica micro powder is (2-5) to (3-8) to (3-6).

In order to investigate the effect of the amount of different components and the subsequent process for preparing the permanent layer on the performance of the permanent layer of the ladle, the present invention provides the following examples and comparative examples, wherein tables 1 and 2 are lists of the raw material addition amounts of the examples and comparative examples of the present invention, and tables 3 and 4 are main process parameters of the examples and comparative examples of the present invention.

TABLE 1 Components List one (wt%)

TABLE 2 Components List two (wt%)

Wherein, the technological parameters for preparing the permanent layer are shown in tables 3 and 4;

TABLE 3 Process parameters List I

TABLE 4 Process parameter List II

The properties of the permanent layers obtained in the above examples were tested, as shown in tables 5 and 6;

TABLE 5 Performance List one

TABLE 6 Performance List two

As shown in table 1, 2, 3 and 4, in examples 1 to 4, by adding a proper amount of bauxite chamotte, natural sintered mullite, light mullite, mullite spheres, calcium aluminate cement, alumina micropowder, silica micropowder, stainless steel fiber, polypropylene fiber and a water reducing agent into the castable according to the addition of the raw materials defined by the invention, and simultaneously controlling the process parameters of uniform mixing time, water addition amount, curing time and baking time, the castable for the permanent layer of the semi-light steel ladle, which has the advantages of low thermal conductivity, good thermal insulation performance, good volume stability, high strength at medium and high temperature, long service life, economy and environmental protection, can be prepared.

In contrast, in comparative examples 1 to 3 in tables 1 and 3 and comparative examples 1 to 6 listed in tables 2 and 4, in which the addition amount of raw materials is not controlled, the castable cannot simultaneously have good heat insulation performance, volume stability and normal-temperature and medium-high-temperature strength, and cannot meet the construction and service performance requirements of products. Specifically, the contents of the light mullite, the mullite balls, the calcium aluminate cement, the alumina micro powder and the silica micro powder have great influence on the performance of the castable.