Castable containing high-carbon ferrochrome slag for iron runner and slag runner and preparation method of castable

Abstract

The invention belongs to the technical field of refractory materials, and discloses a high-carbon ferrochrome slag-containing castable for a tapping channel slag runner, which comprises the following raw materials: 15-58% of high-carbon ferrochrome slag, 10-30% of bauxite, 12-19% of silicon carbide, 5-20% of white corundum fine powder, 7-10% of alumina micro powder, 1-2% of spherical silica micro powder, 1-2% of calcium aluminate cement, an antioxidant and a carbon-containing raw material, and is prepared by the following steps: weighing the raw materials, sequentially putting the raw materials into a stirrer, uniformly stirring to obtain a mixture A; the castable for the iron runner and the slag runner can be obtained. The characteristics of the high-carbon ferro-chrome slag are fully utilized, the high-carbon ferro-chrome slag is applied to the castable of the iron runner and the slag runner, and the adverse effect of oxidation of ferrochrome in the high-carbon ferro-chrome slag on the high-temperature performance of the castable is avoided. The prepared castable has the characteristics of excellent slag corrosion resistance and low cost, the service life of the castable for the tapping channel and the slag runner is effectively prolonged by 30%, and the additional value and the resource utilization level of the high-carbon ferrochrome slag are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of refractory materials, and particularly relates to a high-carbon ferrochrome slag castable for tapping troughs and slag troughs and a preparation method thereof. Background Art

[0002] High-carbon ferrochrome slag is the slag produced by the high-temperature reduction smelting of ferrochrome products from chromite and carbon sources in a submerged arc furnace. For every 1 ton of ferrochrome alloy smelted, more than 1 ton of ferrochrome slag is produced. The main chemical components of ferrochrome slag are Al2O3, MgO, and SiO2. There is a small amount of dispersed residual ferrochrome alloy in the slag, and the main phases are forsterite and spinel. These phases have high refractoriness and high utilization value. At present, a large amount of ferrochrome slag in China is discarded and piled up or used for building roads with low added value. However, due to impurities such as Fe and Ca in the ferrochrome slag, especially the ferrochrome alloy remaining in the high-carbon ferrochrome slag, the volume change caused by oxidation at high temperature will affect the high-temperature volume stability of the refractory material, and the Fe2O3 generated after oxidation enters the refractory matrix and reacts with SiO2, Al2O3, CaO, etc. to generate a large amount of liquid phase, making its use temperature not exceed 1200 °C, greatly reducing the high-temperature performance of the refractory material and restricting its application in refractory materials.

[0003] In order to improve the resource utilization of high-carbon ferrochrome slag and increase its added value, there are also reports in the literature or patents on its application in the fields of refractory materials or ceramics. For example, in the literature "Basic Research on the Properties and Resource Utilization of High-Carbon Ferrochrome Slag", high-carbon ferrochrome slag, magnesia, and alumina raw materials are used to prepare and synthesize a forsterite-spinel composite material to improve the thermal shock stability of the composite material; the patent literature "Chromium Slag Forsterite Refractory Material and Preparation Method" (CN96115173.0) mainly converts high-carbon ferrochrome slag into a high-performance refractory material with forsterite as the main crystal phase by adding a high-temperature binder - magnesia to improve the erosion resistance of alkaline slag; the patent literature "A Method for Preparing a Ladle Castable by Using High-Carbon Ferrochrome Alloy Slag" (CN202010653798.5) realizes the efficient recycling of ferrochrome slag by using MgO, Cr2O3, and magnesium-aluminum spinel in the ferrochrome slag and reduces the manufacturing cost of the ladle castable. The above patents or literatures all utilize the excellent properties of spinel or forsterite in high-carbon ferrochrome alloy slag against alkaline slag to improve or enhance the performance of the material, and do not mention how to eliminate the adverse effects of the small amount of dispersed residual ferrochrome alloy in high-carbon ferrochrome slag on the high-temperature performance of refractory materials at high temperature. Summary of the Invention

[0004] In view of the above problems, the present invention provides a high-carbon ferrochrome slag castable for the taphole slag ditch and its preparation method. The high-carbon ferrochrome slag is applied to the castable for the taphole slag ditch, and a certain amount of silicon carbide, carbon raw material and composite antioxidant are added to the castable to avoid the oxidation of ferrochrome alloy, eliminate the adverse effect of a small amount of dispersed residual ferrochrome alloy in the high-carbon ferrochrome slag on the high-temperature performance of refractories at high temperature, and improve its high-temperature performance when applied to the castable for the taphole slag ditch.

[0005] The technical solution adopted by the present invention: The present invention provides a high-carbon ferrochrome slag castable for the taphole slag ditch. The mass percentage composition of the raw materials is as follows: 15-58% of high-carbon ferrochrome slag with a particle size of 8-0.074 mm, 10-30% of bauxite with a particle size of 8-0.074 mm, 12-19% of silicon carbide with a particle size of 1-0.074 mm, 5-20% of white fused alumina fine powder with a particle size less than 0.044 mm, 7-10% of alumina micropowder, 1-2% of spherical silica powder, 1-2% of calcium aluminate cement, 1-2% of antioxidant, 3.5% of carbon-containing raw material, and 0.1-0.2% of high-efficiency water reducer.

[0006] The preparation method of this high-carbon ferrochrome slag castable is as follows: Weigh and mix the raw materials according to the above mass percentages of the raw materials. Put the raw materials into a mixer in sequence, stir evenly, weigh and bag them to obtain the taphole slag ditch castable containing high-carbon ferrochrome slag. When used on site, pour the bagged castable into a mixer, stir evenly, and then add 3.8-6% of water and stir for 5 minutes to be ready for casting.

[0007] Among them, the high-carbon ferrochrome slag is derived from the slag produced by high-temperature reduction smelting of ferrochrome. It is selected, crushed, and screened into a particle size of 8-0.074 mm, and its bulk density is 3.10-3.20 g / cm 3 , and the apparent porosity is 3.8-4.3%. The main chemical components are Al2O3, MgO, and SiO2.

[0008] Among them, the content of dispersed residual ferrochrome alloy in the high-carbon ferrochrome slag is 1-3 wt%, and the content of metallic chromium in the ferrochrome alloy is 10-40 wt%.

[0009] Among them, the bauxite is high-aluminum bauxite with an Al2O3 content > 80 wt% and an Fe2O3 content < 2 wt%.

[0010] Among them, the SiC content in the silicon carbide > 90 wt%.

[0011] Among them, the alumina micropowder is activated alumina micropowder with a particle size < 10 μm.

[0012] Among them, the antioxidant is a composite antioxidant prepared by configuring metallic silicon and metallic aluminum according to a mass ratio of 10:1.

[0013] Among them, the carbon-containing raw material is one or a combination of two of pitch coke, graphite or carbon black.

[0014] Among them, the high-range water reducing agent is one of polycarboxylate water reducing agent or sodium tripolyphosphate.

[0015] In the present invention, a certain amount of silicon carbide, carbon raw material and composite antioxidant are added to the tapping runner slag runner castable. When the castable is used at high temperature, these components keep the inside of the castable in a reducing atmosphere. After introducing high-carbon ferrochrome slag into the castable, the ferrochrome alloy in the high-carbon ferrochrome slag will not be oxidized inside the castable and stably exists in the castable. The melting point of the ferrochrome alloy is above 1450 °C, and the ferrochrome alloy also plays a role in enhancing the toughness of the castable, avoiding the low-melting substances formed by Fe2O3 generated after the oxidation of the ferrochrome alloy in the high-carbon ferrochrome slag entering the matrix of the castable and reacting with CaO, SiO2, Al2O3, etc., which can greatly improve the high-temperature performance of the tapping runner slag runner castable.

[0016] In addition, when the tapping runner slag runner castable is in use, after the surface layer of the castable contacts with the molten slag, the ferrochrome alloy is oxidized. On the one hand, the chromium oxide generated by oxidation dissolves in the slag, which can increase the viscosity of the slag and effectively prevent the penetration of the slag. On the other hand, the oxidized ferrochrome can also react with alumina and magnesia in the slag to generate high-melting-point composite spinels such as magnesia-aluminum-chromium and magnesia-iron-chromium, effectively improving the slag erosion resistance of the castable.

[0017] The beneficial effects of the present invention are as follows: The present invention utilizes the fact that the ferrochrome alloy in the high-carbon ferrochrome slag can stably exist in a reducing atmosphere, applies the high-carbon ferrochrome slag to the castable of the tapping runner slag runner, and avoids the adverse effect of the oxidation of the ferrochrome alloy in the high-carbon ferrochrome slag on the high-temperature performance of the castable. The prepared tapping runner slag runner castable containing high-carbon ferrochrome slag has excellent high-temperature service performance, slag erosion resistance and low cost. Practical use shows that the service life of the tapping runner slag runner castable has increased by 30% compared with the traditional slag runner castable without adding high-carbon ferrochrome slag, improving the added value and resource utilization level of the high-carbon ferrochrome slag. Description of the Drawings

[0018] Figure 1 is the microstructural morphology diagram of high-carbon ferrochrome slag; Figure 2 is the energy spectrum analysis diagram of ferrochrome alloy.

[0019] Note: Figure 1 The white bright spots in are the dispersed ferrochrome alloy. Detailed Embodiments

[0020] The embodiments of the present invention are described in a relatively specific and detailed manner, but this should not be construed as a limitation on the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

[0021] The following further elaborates on the high-carbon ferrochrome slag castable for the taphole and slag ditch of the present invention and its preparation method through specific examples.

[0022] The high-carbon ferrochrome slag used in the present invention is sourced from the slag generated by the high-temperature reduction smelting of ferrochrome. It is sorted, crushed, and screened into a particle size of 8 - 0.074 mm, with an apparent porosity of 3.8 - 4.3%, and the main chemical components being Al2O3, MgO, and SiO2. As Figure 1-2 shown, the microstructural morphology diagram of the high-carbon ferrochrome slag and the energy spectrum analysis diagram of the ferrochrome alloy are respectively presented. Figure 1 The white bright spots in it are dispersed ferrochrome alloy. It can be seen from the figure that the content of metallic chromium in the ferrochrome alloy accounts for 38.34%. Example 1

[0023] This high-carbon ferrochrome slag castable for the taphole and slag ditch and its preparation method include the following raw material mass percentage composition: 15% of 8 - 0.074 mm high-carbon ferrochrome slag, 30% of 8 - 0.074 mm bauxite, 19% of 1 - 0.074 mm silicon carbide, 20% of 0.044 mm white fused alumina fine powder, 10% of alumina micropowder, 1% of spherical silica powder, 1% of calcium aluminate cement, 1% of antioxidant, 3.5% of graphite, and 0.1% of polycarboxylate water reducer. Weigh according to the above raw material mass percentage, and sequentially put them into a mixer and stir evenly to obtain the high-carbon ferrochrome slag castable for the slag ditch. During on-site use, pour the bagged castable into a mixer, stir evenly, then add 3.8% of water, and stir for 5 minutes to be ready for casting. The detected physical properties are shown in Table 1.

[0024] Table 1 Test performance results

[0025] Example 2 This high-carbon ferrochrome slag castable for the trough of the tapping spout and its preparation method include the following raw materials by mass percentage: 38% of 8 - 0.074mm high-carbon ferrochrome slag, 18% of 8 - 0.074mm bauxite, 12% of 1 - 0.074mm silicon carbide, 13.5% of 0.044mm white fused alumina fine powder, 9% of alumina micropowder, 2% of spherical silica powder, 2% of calcium aluminate cement, 2% of antioxidant, 3.5% of pitch, and 0.15% of high-efficiency water reducer sodium tripolyphosphate. Weigh according to the above mass percentage of raw materials, put them into a mixer in sequence, and stir evenly to obtain the slag trough castable containing high-carbon ferrochrome slag. When used on-site, pour the bagged castable into a mixer, stir evenly, then add 5% water, and stir for 5 minutes to be ready for casting. The detected physical properties are shown in Table 2.

[0026] Table 2 Test Performance Results

[0027] Example 3 This high-carbon ferrochrome slag castable for the trough of the tapping spout and its preparation method include the following raw materials by mass percentage: 58% of 8 - 0.074mm high-carbon ferrochrome slag, 10% of 8 - 0.074mm bauxite, 12% of 1 - 0.074mm silicon carbide, 5% of 0.044mm white fused alumina fine powder, 7% of alumina micropowder, 1.5% of spherical silica powder, 1.5% of calcium aluminate cement, 1.5% of antioxidant, a total of 3.5% of graphite and carbon black, and 0.2% of polycarboxylate water reducer. Weigh according to the above mass percentage of raw materials, put them into a mixer in sequence, and stir evenly to obtain the slag trough castable containing high-carbon ferrochrome slag. When used on-site, pour the bagged castable into a mixer, stir evenly, then add 6% water, and stir for 5 minutes to be ready for casting. The detected physical properties are shown in Table 3.

[0028] Table 3 Test Performance Results

[0029] Comparative Example 58% of 8 - 0.074mm bauxite, 12% of 1 - 0.074mm silicon carbide, 13% of 0.044mm white fused alumina fine powder, 9% of alumina micropowder, 1.5% of spherical silica powder, 1.5% of calcium aluminate cement, 1.5% of antioxidant, 3.5% of carbon-containing raw material, 0.15% of high-efficiency water reducer. Weigh according to the above mass percentage of raw materials, put them into a mixer in sequence, and stir evenly to obtain the slag trough castable without high-carbon ferrochrome slag. When used on-site, pour the bagged castable into a mixer, stir evenly, then add 5% water, and stir for 5 minutes to be ready for casting. The detected physical properties are shown in Table 4.

[0030] Table 4 Test Performance Results

[0031] From the comparison of the performance test results of the slag runner castables prepared by Examples 1-3 and the comparative examples, it can be seen that as the addition amount of high-carbon ferrochrome slag increases, the strength and slag erosion resistance of the measured castables are improved to varying degrees.

Claims

1. A high-carbon ferrochrome slag castable for a slag ditch for a tapping ditch, characterized in that: The mass percentage composition of the raw materials is: 15-58% of high-carbon ferrochrome slag with a particle size of 8-0.074mm, 10-30% of bauxite with a particle size of 8-0.074mm, 12-19% of silicon carbide with a particle size of 1-0.074mm, 5-20% of white corundum fine powder with a particle size less than 0.044mm, 7-10% of alumina powder, 1-2% of spherical silicon powder, 1-2% of calcium aluminate cement, 1-2% of antioxidant, 3.5% of carbon-containing raw materials, and 0.1-0.2% of high-efficiency water reducer.

2. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: High carbon ferrochrome slag comes from the slag produced by high temperature reduction smelting of ferrochrome. It is selected, crushed and sieved into a particle size of 8 to 0.074 mm. Its bulk density is 3.10 to 3.20 g / cm 3 The apparent porosity is 3.8-4.3%, and the main chemical components are Al2O3, MgO, and SiO2.

3. A high-carbon ferrochromium slag castable for a slag ditch of a tapping ditch according to claim 1 or 2, characterized in that: The high carbon ferrochrome slag contains 1-3wt% of ferrochrome alloy dispersed in the ferrochrome slag, and the content of metallic chromium in the ferrochrome alloy is 10-40wt%.

4. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: The bauxite is a high-alumina bauxite with an Al2O3 content of more than 80wt% and a Fe2O3 content of less than 2wt%.

5. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: The SiC content in silicon carbide is >90wt%.

6. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: The alumina powder is activated alumina powder with a particle size of less than 10 μm.

7. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: The antioxidant is a composite antioxidant prepared by mixing metal silicon and metal aluminum in a mass ratio of 10:

1.

8. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: The carbon-containing raw material is one of pitch, graphite or carbon black or a combination of the two.

9. The high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: The high-efficiency water reducer is one of polycarboxylate water reducers or sodium tripolyphosphate.

10. The method for preparing a high-carbon ferrochromium slag castable for a slag channel of a slag channel of a slag channel according to claim 1, characterized in that: Weigh and prepare the raw materials according to the mass percentage of their composition, put the raw materials into the mixer in turn, stir them thoroughly and evenly, weigh and bag them, then you can get the iron ditch slag ditch castable containing high carbon ferrochrome slag; when using on site, pour the bagged castable into the mixer and stir it evenly, then add 3.8-6% of water, stir for 5 minutes and then pour it for use.

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