Method for preparing black microlite from titanium-containing blast furnace slag

Abstract

The invention discloses a method for preparing black microlite from titanium-containing blast furnace slag, which comprises the following steps: mixing the titanium-containing blast furnace slag with a hardening and tempering agent in a cold state to obtain mixed slag, and the mass of the hardening and tempering agent is not more than 10% of the total mass of the mixed slag; melting, heat preservation and casting are conducted on the mixed slag to obtain a formed sample, then crystallization treatment is conducted, cooling is conducted, then the black microlite is obtained, preparation of the pure black microlite without expensive additional dark coloring agents is achieved, and the utilization rate of the titanium-containing blast furnace slag which is solid waste is increased.

Description

Technical Field

[0001] This application relates to a method for preparing black microcrystalline stone from titanium-containing blast furnace slag, belonging to the field of resource comprehensive utilization technology. Background Technology

[0002] With rapid economic development, industrial production, while bringing economic benefits, also continuously generates a large amount of industrial waste. Industrial waste slag is difficult to treat due to its large volume, diverse types, poor flowability, and large fluctuations in composition. Titanium-containing blast furnace slag is a solid waste generated during the smelting of vanadium-titanium ore. Its high TiO2 content significantly degrades the hydration reaction activity, making it unsuitable for direct use in cement production. Current technologies for enriching and recovering titanium from slag are still immature. Currently, titanium can only be extracted from medium-to-high titanium slag, and these methods generally suffer from high energy consumption, low extraction rates, and significant environmental pollution. A large amount of titanium-containing slag is still disposed of through landfill, which not only occupies land resources and pollutes the environment but also wastes valuable resources within the slag.

[0003] Titanium-containing blast furnace slag belongs to the CaO-MgO-Al2O3-SiO2 system, and its chemical composition theoretically meets the requirements for microcrystalline stone manufacturing. Microcrystalline stone, as a novel material widely used in metallurgy, power, and building materials, possesses superior structural strength compared to natural stone and can replace it, thus protecting the environment. However, in existing technologies, the preparation of microcrystalline stone from titanium-containing blast furnace slag still faces a series of difficulties.

[0004] Patent CN118373598A discloses a microcrystalline glass, its preparation method, and production equipment. This process requires coordinating the proportions of various slag materials, limiting the practical application ratio of titanium-containing slag. Furthermore, the composition of the raw material system fluctuates significantly, hindering stable control of the production process and increasing the complexity and cost of raw material supply coordination. Patent CN119241078A discloses a microcrystalline cast stone, its preparation method, and its application. It proposes an effective approach for the synergistic preparation of microcrystalline cast stone using multiple solid wastes. However, the use of multiple solid wastes reduces the utilization rate of vanadium-titanium tailings and requires the addition of nucleating agents and crystallization aids, leading to a complex formulation system. The supply of multiple requirements affects product performance and increases production costs. Patent CN106242301A discloses a black microcrystalline glass brick using liquid converter steel slag as the main raw material and its preparation method. While this method improves the utilization rate of steel slag and yields products with good wear resistance and compressive strength, it requires the addition of precious metal oxides such as cobalt oxide and nickel oxide as colorants, significantly increasing production costs. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings of the prior art and provide a method for preparing black microcrystalline stone from titanium-containing blast furnace slag. The method involves mixing a conditioning agent with titanium-containing blast furnace slag and controlling the precipitation of the crystalline phase of the microcrystalline stone through the conditioning agent. Pure black microcrystalline stone can be prepared without the need to add expensive dark coloring agents, thereby improving the utilization rate of titanium-containing blast furnace slag as solid waste.

[0006] To achieve the above objectives, this application employs the following technical solution: This application provides a method for preparing black microcrystalline stone from titanium-containing blast furnace slag, comprising: Titanium-containing blast furnace slag is cold-mixed with a conditioning agent to obtain a mixed slag, wherein the mass of the conditioning agent is no more than 10% of the total mass of the mixed slag; The mixed slag is melted and kept at a constant temperature, then cast to obtain a shaped sample; The shaped sample was subjected to crystallization treatment and then cooled to obtain black microcrystalline stone.

[0007] Furthermore, the chemical composition of the titanium-containing blast furnace slag, by mass percentage, includes: CaO: 20%-36%; MgO: 5%-15%; SiO2: 20%-32%; Al2O3: 8%-16%; TiO2: 5%-25%; Fe2O3: 0-10%; other components: 0-2%.

[0008] Furthermore, the chemical composition of the mixed slag after melting and heat preservation, expressed as a percentage by mass, includes: CaO: 18%-36%; MgO: 4.5%-15%; SiO2: 18%-32%; Al2O3: 7.2%-16%; TiO2: 4%-25%; Fe2O3: 0-10%; Cr2O3: 0-1%; C: 0-1%; Other components: 0-2%.

[0009] Furthermore, the other components include any two or more of K2O, Na2O, V2O5, and MnO.

[0010] Furthermore, the mass ratio of the titanium-containing blast furnace slag to the conditioning agent is 9:1 to 99:1.

[0011] Furthermore, the conditioning agent includes any one or more mixtures of Cr2O3, Fe2O3, carbon powder, and quartz sand.

[0012] Furthermore, the melting and heat preservation temperature is 1450°C. o C-1530 o C, time is 30-100 minutes.

[0013] Furthermore, the crystallization treatment temperature is 850°C. o C-950o C, time is 5min-30min; after crystallization treatment, the temperature is cooled at a cooling rate of 2℃ / min-5℃ / min or cooled in the furnace to obtain black microcrystalline stone.

[0014] Furthermore, the mold used for casting includes a graphite mold or a stainless steel mold, which is preheated to 200°C before use. o C-450 o C.

[0015] Furthermore, the crystal phase of the black microcrystalline stone includes titanium pyroxene and magnesium chromium spinel, or titanium pyroxene and iron magnesium spinel. The water absorption rate of the black microcrystalline stone is less than 0.5%, the Vickers hardness is not less than 950 Hv, and the density is not less than 3.2 g / cm³.

[0016] Compared with the prior art, the beneficial effects achieved by this application are as follows: This application provides a method for preparing black microcrystalline stone from titanium-containing blast furnace slag. The utilization rate of titanium-containing blast furnace slag, which is a solid waste, is over 90%, realizing the effective utilization of waste resources. Moreover, the black microcrystalline stone obtained has a simple composition, consisting only of titanium-containing blast furnace slag and a small amount of conditioning agent, reducing the cost of large-scale production. By using the chemical composition of titanium-containing blast furnace slag as the main coloring element and adding a small amount of conditioning agent to control the crystal phase, a pure and stable black microcrystalline stone is obtained. The resulting black microcrystalline stone has a water absorption rate of less than 0.5%, a Vickers hardness of not less than 950 Hv, and a density of not less than 3.2 g / cm³, thus enhancing its market competitiveness. Attached Figure Description

[0017] Figure 1 A process flow diagram for preparing black microcrystalline stone from titanium-containing blast furnace slag is provided in this application embodiment; Figure 2 A cross-sectional view of the black microcrystalline stone prepared in Example 1; Figure 3 The XRD pattern of the black microcrystalline stone prepared in Example 1; Figure 4 EDS image of the black microcrystalline stone prepared in Example 1; Figure 5 Cross-sectional view of the black microcrystalline stone prepared in Example 2; Figure 6 The XRD pattern of the black microcrystalline stone prepared in Example 2; Figure 7 EDS image of the black microcrystalline stone prepared in Example 2; Figure 8 A cross-sectional view of the black microcrystalline stone prepared in Example 3; Figure 9Cross-sectional view of the black microcrystalline stone prepared in Comparative Example 1; Figure 10 The image shows a cross-sectional view of the black microcrystalline stone prepared in Comparative Example 2. Detailed Implementation

[0018] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof.

[0019] This application provides a method for preparing black microcrystalline stone from titanium-containing blast furnace slag, such as... Figure 1 The diagram shown is a process flow chart for preparing black microcrystalline stone from titanium-containing blast furnace slag according to an embodiment of this application, including the following steps: (1) Mix titanium-containing blast furnace slag with a conditioning agent in a cold state to obtain a mixed slag; the conditioning agent includes, but is not limited to, any one or more of Cr2O3, Fe2O3, graphite carbon, and quartz sand; the specific amount of conditioning agent added should refer to the composition of the titanium-containing blast furnace slag actually used, and ensure that the composition of the homogenized glass melt is within the required range.

[0020] (2) Mixed slag at 1450 o Melt and hold at a temperature above C for 30-120 minutes.

[0021] (3) After melting and holding at a constant temperature, the homogenized glass melt is poured into a mold, cooled, and then demolded to obtain a molded sample; the mold includes, but is not limited to, graphite molds and stainless steel molds, and the molds need to be heated to 200-450°C before use. o C is used.

[0022] (4) The molded sample is placed in a crystallization furnace for crystallization treatment at a temperature of 850-950°C. o C, crystallization time is 5-30 minutes; after crystallization, use 2-5... o Cooling is performed at the cooling rate of C, or the furnace is cooled to 100°C. o When the concentration is below C, black microcrystalline stone is obtained.

[0023] In this embodiment of the application, the titanium-containing blast furnace slag comprises: CaO: 20%-36%; MgO: 5%-15%; SiO2: 20%-32%; Al2O3: 8%-16%; TiO2: 5%-25%; Fe2O3: 0-10%; other components: 0-3%.

[0024] The other components include any two or more of K2O, Na2O, V2O5, and MnO.

[0025] In some embodiments of this application, the glass melt after melting the aforementioned cold mixed slag comprises: CaO: 18%-38%; MgO: 4.5%-14.5%; SiO2: 18%-38%; Al2O3: 4.5%-19%; TiO2: 4%-24%; Fe2O3: 4.5%-15%; Cr2O3: 0-1%; C: 0-1%; Others: 0-3%.

[0026] The other components include two or more of K2O, Na2O, V2O5, and MnO.

[0027] In this embodiment, the temperature at which the molten slag is kept in a molten state is generally higher than 1450°C. o C; The preferred temperature in the molten state is 1450-1530℃. o C.

[0028] In this embodiment of the application, the crystallization temperature is 850-950°C. o C, for example, 850 o C, 900 o C, 950 o C; The crystallization temperature is 5-30 min, for example 5 min, 10 min, 15 min, 30 min.

[0029] In some embodiments of this application, the cooling method is to cool at a rate of 2-5°C / min, or to cool in the furnace to below 100°C.

[0030] In the specific embodiments of this application, unless otherwise specified, the experimental environment and parameter conditions of each group in the test are kept consistent, except for explicitly indicated differences. The following is a further description of a method for preparing black microcrystalline stone from titanium-containing blast furnace slag provided in this application.

[0031] Example 1:

[0032] This embodiment provides a method for preparing black microcrystalline stone from titanium-containing blast furnace slag. The raw materials include titanium-containing blast furnace slag and a conditioning agent. The titanium-containing blast furnace slag accounts for 99% of the total mass percentage, and the conditioning agent accounts for 1% of the total mass percentage. The conditioning agent includes a mixture of Cr2O3 and carbon powder.

[0033] The composition of titanium-containing blast furnace slag, by mass percentage, is as follows: CaO: 27.78%; MgO: 7.85%; SiO2: 26.08%; Al2O3: 12.10%; TiO2: 19.68%; Fe2O3: 4.57%; K2O: 0.32%; Na2O: 0.46%; V2O5: 0.37%.

[0034] The specific preparation process is as follows: (1) The titanium-containing blast furnace slag and the conditioning agent were mixed in a cold state, and the resulting mixed slag was melted at 1500 °C. o Melt and hold at C for 100 min; the glass melt composition of the mixed slag, by mass percentage, is as follows: CaO: 26.50%; MgO: 7.77%; SiO2: 25.82%; Al2O3: 11.98%; TiO2: 19.48%; Fe2O3: 4.52%; Cr2O3: 0.5%; C: 0.5%; K2O: 0.32%; Na2O: 0.46%; V2O5: 0.36%.

[0035] (2) After the molten slag is poured into the mold and cooled and formed, it is demolded to obtain the molded sample.

[0036] (3) The molded sample is sent into a crystallization furnace for crystallization treatment at a temperature of 900°C. o C, after holding at this temperature for 15 minutes, is cooled in the furnace to obtain black microcrystalline stone.

[0037] (4) Cutting black microcrystalline stone, such as Figure 2 As shown, its cross-section is black, with almost no internal pores, and the overall structure is relatively dense. The XRD and EDS results of the sample are as follows: Figure 3 , Figure 4 As shown, the main crystalline phase is titanium-containing pyroxene, with some magnesium-chromium spinel phase also present. The density of the black microcrystalline sample obtained in this example was determined to be 3.21 g / cm³. 3 It has a water absorption rate of 0.18% and a Vickers hardness of 982 Hv.

[0038] Example 2:

[0039] This embodiment provides a method for preparing black microcrystalline stone from titanium-containing blast furnace slag. The raw materials mainly include titanium-containing blast furnace slag and a conditioning agent. The titanium-containing blast furnace slag accounts for 90% of the total mass percentage, and the conditioning agent accounts for 10% of the total mass percentage. The conditioning agent is mainly a mixture of Fe2O3 and carbon powder.

[0040] The composition of titanium-containing blast furnace slag, by mass percentage, is as follows: CaO: 27.78%; MgO: 7.85%; SiO2: 26.08%; Al2O3: 12.10%; TiO2: 19.68%; Fe2O3: 4.57%; K2O: 0.32%; Na2O: 0.46%; V2O5: 0.37%.

[0041] The specific preparation process is as follows: (1) The titanium-containing blast furnace slag is cold-mixed with a conditioning agent, and the resulting mixed slag is melted at 1500 °C. oMelt and hold at C for 100 min; the glass melt composition of the mixed slag, by mass percentage, is as follows: CaO: 26.21%; MgO: 7.41%; SiO2: 24.60%; Al2O3: 11.42%; TiO2: 18.57%; Fe2O3: 9.97%; C: 0.5%; K2O: 0.29%; Na2O: 0.43%; V2O5: 0.36%.

[0042] (2) After the molten slag is poured into the mold and cooled and formed, it is demolded to obtain the molded sample.

[0043] (3) The molded sample is sent into a crystallization furnace for crystallization treatment at a temperature of 900°C. o C, after holding at this temperature for 15 minutes, is cooled in the furnace to obtain black microcrystalline stone.

[0044] (4) Cut the black microcrystalline stone sample, such as Figure 5 As shown, the cross-section is blackish-gray. The XRD and EDS results of the black microcrystalline stone sample in this embodiment are as follows: Figure 6 , Figure 7 As shown, the main crystalline phase is titanium-containing pyroxene, with some magnesium spinel phase also present. The density of this black microcrystalline sample was determined to be 3.2 g / cm³. 3 It has a water absorption rate of 0.49% and a Vickers hardness of 957 Hv.

[0045] Example 3:

[0046] This embodiment provides a method for preparing black microcrystalline stone from titanium-containing blast furnace slag. The raw materials mainly include titanium-containing blast furnace slag and a conditioning agent. The titanium-containing blast furnace slag accounts for 94% of the total mass percentage, and the conditioning agent accounts for 6% of the total mass percentage, wherein the conditioning agent is Fe2O3.

[0047] The composition of titanium-containing blast furnace slag, by mass percentage, is as follows: CaO: 27.78%; MgO: 7.85%; SiO2: 26.08%; Al2O3: 12.10%; TiO2: 19.68%; Fe2O3: 4.57%; K2O: 0.29%; Na2O: 0.43%; V2O5: 0.36%.

[0048] The process for obtaining microcrystalline stone in this embodiment is as follows: (1) The titanium-containing blast furnace slag is cold-mixed with a conditioning agent, and the resulting mixed slag is melted at 1500 °C. oMelt and hold at C for 100 min; the glass melt composition of the mixed slag, by mass percentage, is: CaO: 26.21%; MgO: 7.41%; SiO2: 24.60%; Al2O3: 11.42%; TiO2: 18.57%; Fe2O3: 9.97%; K2O: 0.29%; Na2O: 0.43%; V2O5: 0.36%.

[0049] (2) After the molten slag is poured into the mold and cooled and formed, it is demolded to obtain the molded sample.

[0050] (3) The molded sample is sent into a crystallization furnace for crystallization treatment at a temperature of 920°C. o C, after holding at this temperature for 30 minutes, is cooled in the furnace to obtain a microcrystalline stone sample.

[0051] (4) Cut the microcrystalline stone sample, such as... Figure 8 As shown, Figure 8 The sample cross-section appears black, with almost no internal pores, and is generally quite dense. The sample density was measured to be 3.24 g / cm³. 3 It has a water absorption rate of 0.16% and a Vickers hardness of 985 Hv.

[0052] Comparative Example 1: Comparative Example 1 uses a different ratio of conditioning agent than the Example. The main raw materials include titanium-containing blast furnace slag and conditioning agent. The titanium-containing blast furnace slag accounts for 85% of the total mass percentage, and the conditioning agent accounts for 15% of the total mass percentage. The conditioning agent is quartz sand.

[0053] The composition of titanium-containing blast furnace slag, by mass percentage, is as follows: CaO: 27.78%; MgO: 7.85%; SiO2: 26.08%; Al2O3: 12.10%; TiO2: 19.68%; Fe2O3: 4.57%; K2O: 0.32%; Na2O: 0.46%; V2O5: 0.37%.

[0054] The process for preparing microcrystalline stone in this comparative example is as follows: (1) The titanium-containing blast furnace slag is cold-mixed with a conditioning agent, and the resulting mixed slag is melted at 1500 °C. o Melt and hold at C for 100 min; the glass melt composition of the mixed slag, by mass percentage, is as follows: CaO: 23.61%; MgO: 6.67%; SiO2: 37.17%; Al2O3: 10.26%; TiO2: 16.73%; Fe2O3: 3.88%; K2O: 0.49%; Na2O: 0.83%; V2O5: 0.36%.

[0055] (2) After pouring the slag obtained in the above steps into the mold and cooling it into shape, demold it to obtain the molded sample.

[0056] (3) The molded sample is sent into a crystallization furnace for crystallization treatment at a temperature of 900°C. o C, after holding at this temperature for 30 minutes, is cooled in the furnace to obtain a microcrystalline stone sample.

[0057] (4) Cut the microcrystalline stone sample, such as... Figure 9 As shown, the cross-section of the microcrystalline stone sample exhibits a brownish-black mixed appearance, with almost no internal pores, and is generally quite dense. The density of the microcrystalline stone sample is 3.22 g / cm³. 3 It has a water absorption rate of 0.17% and a Vickers hardness of 987 Hv.

[0058] Comparative Example 2: Comparative Example 2 uses a different conditioning agent than the Example. The raw materials mainly include titanium-containing blast furnace slag and conditioning agent. The titanium-containing blast furnace slag accounts for 96% of the total mass percentage, and the conditioning agent accounts for 4% of the total mass percentage. The conditioning agent is MnO2.

[0059] The composition of titanium-containing blast furnace slag, by mass percentage, is as follows: CaO: 27.78%; MgO: 7.85%; SiO2: 26.08%; Al2O3: 12.10%; TiO2: 19.68%; Fe2O3: 4.57%; K2O: 0.29%; Na2O: 0.43%; V2O5: 0.36%.

[0060] The process for preparing microcrystalline stone in this comparative example is as follows: (1) Titanium-containing blast furnace slag is cold-mixed with a conditioning agent, and the resulting mixed slag is melted at 1500 °C. o Melt and hold at C for 100 min; the glass melt composition of the mixed slag, by mass percentage, is as follows: CaO: 26.71%; MgO: 7.55%; SiO2: 25.08%; Al2O3: 11.63%; TiO2: 18.92%; Fe2O3: 4.24%; MnO2: 4%; K2O: 0.30%; Na2O: 0.44%; V2O5: 0.37%.

[0061] (2) After the molten slag is poured into the mold and cooled and formed, it is demolded.

[0062] (3) The molded sample is sent into a crystallization furnace for crystallization treatment at a temperature of 920°C. o C, after holding at this temperature for 30 minutes, is cooled in the furnace to obtain a microcrystalline stone sample.

[0063] (4) Cut the microcrystalline stone sample, such as... Figure 10 As shown, the sample cross-section exhibits a mixture of blackish-gray and a large amount of brown, with numerous micropores inside. The sample density was determined to be 3.14 g / cm³. 3It has a water absorption rate of 0.72% and a Vickers hardness of 931 Hv.

[0064] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for preparing black microcrystalline stone from titanium-containing blast furnace slag, characterized in that, include: Titanium-containing blast furnace slag is cold-mixed with a conditioning agent to obtain a mixed slag, wherein the mass of the conditioning agent is no more than 10% of the total mass of the mixed slag; The mixed slag is melted and kept at a constant temperature, then cast to obtain a shaped sample; The shaped sample was subjected to crystallization treatment and then cooled to obtain black microcrystalline stone.

2. The method according to claim 1, characterized in that, The chemical composition of the titanium-containing blast furnace slag, by mass percentage, includes: CaO: 20%-36%; MgO: 5%-15%; SiO2: 20%-32%; Al2O3: 8%-16%; TiO2: 5%-25%; Fe2O3: 0-10%; other components: 0-2%.

3. The method according to claim 1, characterized in that, The chemical composition of the mixed slag after melting and heat preservation, expressed as a percentage by mass, includes: CaO: 18%-36%; MgO: 4.5%-15%; SiO2: 18%-32%; Al2O3: 7.2%-16%; TiO2: 4%-25%; Fe2O3: 0-10%; Cr2O3: 0-1%; C: 0-1%; Other components: 0-2%.

4. The method according to claim 2 or claim 3, characterized in that, The other components include any two or more of K2O, Na2O, V2O5, and MnO.

5. The method according to claim 1, characterized in that, The mass ratio of the titanium-containing blast furnace slag to the conditioning agent is 9:1 to 99:

1.

6. The method according to claim 1, characterized in that, The conditioning agent includes any one or more mixtures of Cr2O3, Fe2O3, carbon powder, and quartz sand.

7. The method according to claim 1, characterized in that, The melting and heat preservation temperature is 1450°C. o C-1530 o C, time is 30-100 minutes.

8. The method according to claim 1, characterized in that, The crystallization treatment temperature is 850°C. o C-950 o C, time is 5min-30min; after crystallization treatment, the temperature is cooled at a cooling rate of 2℃ / min-5℃ / min or cooled in the furnace to obtain black microcrystalline stone.

9. The method according to claim 1, characterized in that, The molds used for casting include graphite molds or stainless steel molds, which are preheated to 200°C before use. o C-450 o C.

10. The method according to claim 1, characterized in that, The black microcrystalline stone has a crystal phase including titanium pyroxene and magnesium chromium spinel, or titanium pyroxene and iron magnesium spinel. The black microcrystalline stone has a water absorption rate of less than 0.5%, a Vickers hardness of not less than 950 Hv, and a density of not less than 3.2 g / cm³.

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