Black steel slag microcrystalline plate and preparation method thereof

Abstract

The invention belongs to the technical field of solid waste resource utilization, and particularly relates to a black steel slag microcrystalline plate and a preparation method thereof. The black steel slag microcrystalline plate is prepared from the following raw materials in percentage by mass: 48 to 52 percent of steel slag, 33 to 37 percent of bottom slag, 8.5 to 10.5 percent of sodium carbonate, 0.5 to 1 percent of sodium sulfide, 3 to 3.5 percent of sodium fluosilicate, 0.6 to 0.8 percent of barium titanate, 0.04 to 0.06 percent of porous graphene microflowers, 0.2 to 0.3 percent of cerium fluoride, 0.6 to 0.8 percent of sodium pyrophosphate and 0.02 to 0.03 percent of color complementing agent. According to the black steel slag microcrystal plate and the preparation method thereof, the solid waste absorption amount and the product additional value are remarkably improved, a brand new scheme is provided for low-cost green manufacturing of the black microcrystal plate through the technical path of color control with waste, and the black steel slag microcrystal plate and the preparation method thereof have remarkable environmental benefits and industrialization prospects.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, specifically to a black steel slag microcrystalline plate and its preparation method. Background Technology

[0002] With the rapid development of the steel industry, the global annual steel slag production exceeds hundreds of millions of tons, and my country, as a major steel producer, has a particularly large accumulation of steel slag. Traditional steel slag disposal methods mainly involve landfilling or low-value utilization (such as roadbed materials), which not only consumes land resources but also easily leads to environmental pollution due to residual heavy metals and alkaline substances in the steel slag. Meanwhile, the bottom ash from the incineration of sludge in municipal wastewater treatment plants (hereinafter referred to as "bottom ash"), as a typical type of general industrial solid waste, is also seeing its annual production increase year by year. This type of bottom ash has a complex composition, typically containing inorganic components such as SiO2, Al2O3, MgO, and CaO, as well as a small amount of unburned organic matter. Direct landfilling or open-air storage can easily cause dust pollution and the risk of heavy metal leaching. Therefore, how to synergistically transform steel slag and bottom ash into high-value-added materials has become an important issue in the field of solid waste resource utilization.

[0003] Microcrystalline sheets (also known as microcrystalline glass or microcrystalline ceramics) are widely used in building decoration and chemical corrosion protection due to their combination of the molding advantages of glass and the high strength, wear resistance, and corrosion resistance of ceramics. Using steel slag and bottom slag as the main raw materials to prepare microcrystalline sheets can both dispose of large quantities of solid waste and reduce raw material costs, aligning with the needs of the circular economy and the "dual-carbon" strategy. However, current research on steel slag-based microcrystalline sheets focuses primarily on optimizing mechanical properties, with a lack of research on color control, especially dark colors (such as glossy black). Black sheets, however, have significant market value in high-end building curtain walls and wear-resistant flooring.

[0004] Although both steel slag and bottom slag contain silicon, calcium, aluminum, and other components required for glass-ceramics, their physicochemical properties differ significantly: steel slag has a higher FeO / Fe2O3 content and contains small amounts of transition metal elements such as Mn, while bottom slag is mainly composed of SiO2 and Al2O3. In existing technologies, when using steel slag alone to prepare glass-ceramics, the Fe... 2+ / Fe 3+ Fluctuations in the proportion of steel slag and bottom slag can easily lead to uneven color (such as yellowish-brown or dark green). Furthermore, bottom slag, due to its large compositional fluctuations and high impurity content, is prone to porosity and cracks when melted alone, making it difficult to form a dense structure. Therefore, exploring an environmentally friendly and economical resource utilization pathway for steel slag and bottom slag is crucial. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a black steel slag microcrystalline plate and its preparation method, to solve the problems of large steel slag accumulation, complex bottom slag composition, and significant environmental impact in the prior art. Furthermore, when using steel slag alone to prepare microcrystalline glass, the Fe...2+ / Fe 3+ Fluctuations in the proportions can easily cause problems such as uneven color (e.g., yellowish-brown or dark green).

[0006] To achieve the above and other related objectives, the present invention is obtained through the following technical solution.

[0007] The first aspect of this invention provides a black steel slag microcrystalline plate, wherein the raw materials of the black steel slag microcrystalline plate, by mass percentage, include: 48-52% steel slag, 33-37% bottom slag, 8.5-10.5% soda ash, 0.5-1% sodium sulfide, 3-3.5% sodium fluorosilicate, 0.6-0.8% barium titanate, 0.04-0.06% porous graphene micron flowers, 0.2-0.3% cerium fluoride, 0.6-0.8% sodium pyrophosphate, and 0.02-0.03% colorant.

[0008] In some embodiments of the present invention, the raw materials of the black steel slag microcrystalline plate, by mass percentage, include: 50% steel slag, 35% bottom slag, 9.4% soda ash, 0.7% sodium sulfide, 3.2% sodium fluorosilicate, 0.68% barium titanate, 0.05% porous graphene micron flowers, 0.25% cerium fluoride, 0.7% sodium pyrophosphate, and 0.02% colorant.

[0009] In some embodiments of the present invention, the bottom ash is the ash produced by the fluidized bed incineration of sludge from a municipal wastewater treatment plant.

[0010] In some embodiments of the present invention, the complementary colorant includes cobalt oxide and nickel oxide.

[0011] In some embodiments of the present invention, the mass ratio of cobalt oxide to nickel oxide is 1:(3-4).

[0012] In some embodiments of the present invention, the particle size of the steel slag is ≥40 mesh.

[0013] In some embodiments of the present invention, the steel slag comprises the following oxides in the following mass percentages: MgO 7-9%, Al2O3 4-6%, SiO2 16-18%, MnO 2-3%, CaO 43-45%, Fe2O3 14-16%, P2O5 1-2%, with the balance being other oxides.

[0014] In some embodiments of the present invention, the particle size of the bottom slag is ≥60 mesh.

[0015] In some embodiments of the present invention, the bottom slag comprises the following oxides in the following mass percentages: MgO 0.3-0.7%, Al2O3 4-5%, SiO2 89-90%, CaO 0.3-0.6%, Fe2O3 0.5-1%, P2O5 1.5-2%, with the balance being other oxides.

[0016] In some embodiments of the present invention, the porous graphene microflowers have a 3D porous folded structure and a specific surface area ≥220m². 2 / g, density is 40-48mg / cm³ 3 .

[0017] The second aspect of the present invention provides a method for preparing black steel slag microcrystalline plates, comprising the following steps: the material is melted in the main melting pool, flow channel, rising channel and material channel of an all-electric melting furnace, and then flows out through the discharge port at the end of the material channel, and is pressed into plates by a rolling mill, and the plates are crystallized, cut and polished to obtain black steel slag microcrystalline plates.

[0018] In some embodiments of the present invention, the temperature of the main molten pool is room temperature - 1550°C, and the residence time is 11 hours.

[0019] In some embodiments of the present invention, the surface temperature of the material above the main molten pool is ≤200°C.

[0020] In some embodiments of the present invention, the temperature of the flow cavity is 1550-1500°C and the residence time is 40 min.

[0021] In some embodiments of the present invention, the temperature of the ascending channel is 1500-1450°C, and the residence time is 2 hours.

[0022] In some embodiments of the present invention, the temperature of the feed channel is 1450-1370°C and the residence time is 3.5h.

[0023] In some embodiments of the present invention, the thickness of the plate is 12-20 mm.

[0024] In some embodiments of the present invention, the crystallization temperature is divided into a first temperature control segment, a second temperature control segment, a third temperature control segment, a fourth temperature control segment, a fifth temperature control segment, a sixth temperature control segment, a seventh temperature control segment, and an eighth temperature control segment; the first temperature control segment: 600-680℃, with uniform heating for 30 minutes; the second temperature control segment: 680-760℃, with uniform heating for 120 minutes; the third temperature control segment: 760-820℃, with uniform heating for 50 minutes; the fourth temperature control segment: ... Temperature control section 1: 820-860℃, uniform heating rate, heating time 80min; Temperature control section 2: 860℃ constant, holding time 40min; Temperature control section 3: 860-650℃, uniform cooling rate, cooling time 60min; Temperature control section 4: 650-500℃, uniform cooling rate, cooling time 100min; Temperature control section 5: 500-700℃, uniform cooling rate, cooling time 100min; Temperature field uniformity of each temperature control section is ±5℃, temperature control accuracy is ±1℃.

[0025] In some embodiments of the present invention, the plate is glossy black after polishing.

[0026] As described above, the black steel slag microcrystalline plate and its preparation method of the present invention have the following beneficial effects:

[0027] The black steel slag microcrystalline board and its preparation method provided by this invention not only significantly improve the amount of solid waste disposal and product added value, but also provide a brand-new solution for low-cost green manufacturing of black microcrystalline board through the "waste-controlled color" technical path, which has significant environmental benefits and industrialization prospects. Detailed Implementation

[0028] The following details a black steel slag microcrystalline plate and its preparation method according to the present invention.

[0029] Black steel slag microcrystalline slab

[0030] The first aspect of this invention provides a black steel slag microcrystalline plate. The raw materials for the black steel slag microcrystalline plate, by weight percentage, include: steel slag 48-52%, optionally 48-49%, 49-49.5%, 49.5-50%, 50-51%, 51-52%, 48-50%, 50-52%, 49-51%, preferably 50%; and bottom slag 33-37%, optionally 33-34%, 34-35%, 35-35.7%, 35.7-35.8%, 35.8-37%, 33-35.7%, 35%... 0.7-37%, preferably 35%; soda ash 8.5-10.5%, optionally 8.5-9%, 9-9.3%, 9.3-9.5%, 9.5-10%, 8.5-9.3%, 9.3-10%, preferably 9.4%; sodium sulfide 0.5-1%, optionally 0.5-0.6%, 0.6-0.7%, 0.7-0.73%, 0.73-0.9%, 0.9-1%, 0.5-0.73%, 0.73-1%, preferably 0.7%; sodium fluorosilicate 3-3.5%, optionally 3-3. 1%, 3.1-3.2%, 3.2-3.3%, 3.3-3.5%, 3-3.2%, 3.2-3.5%, preferably 3.2%; barium titanate 0.6-0.8%, optionally 0.6-0.68%, 0.68-0.69%, 0.69-0.8%, 0.6-0.69%, preferably 0.68%; porous graphene micron flowers 0.04-0.06%, optionally 0.04-0.05%, 0.05-0.06%, preferably 0.05%; cerium fluoride 0.2-0.3%, optionally... 0.2-0.22%, 0.22-0.23%, 0.23-0.24%, 0.24-0.25%, 0.24-0.3%, 0.2-0.23%, 0.23-0.3%, preferably 0.25%; sodium pyrophosphate 0.6-0.8%, optionally 0.6-0.68%, 0.68-0.7%, 0.7-0.73%, 0.73-0.8%, 0.6-0.7%, 0.7-0.8%, preferably 0.7%; colorant 0.02-0.03%, preferably 0.02%.

[0031] The black steel slag microcrystalline plate provided by this invention comprises, by mass percentage: 50% steel slag, 35% bottom slag, 9.4% soda ash, 0.7% sodium sulfide, 3.2% sodium fluorosilicate, 0.68% barium titanate, 0.05% porous graphene micron flowers, 0.25% cerium fluoride, 0.7% sodium pyrophosphate, and 0.02% colorant.

[0032] In the black steel slag microcrystalline plate provided by the present invention, the bottom slag is the grate ash produced by the fluidized bed incineration of sludge from a municipal sewage treatment plant.

[0033] The black steel slag microcrystalline plate provided by this invention uses cobalt oxide and nickel oxide as colorants. The mass ratio of cobalt oxide to nickel oxide is 1:(3-4). This invention achieves precise control of the deep, glossy black color of the microcrystalline plate through the synergistic coupling mechanism of the endogenous colorant and the colorant in steel slag. Its core mechanism lies in the complementary spectral absorption and synergistic optimization of electronic states of multiple metal ions. Steel slag is rich in Fe... 3+ Fe 2+ 、Mn 2+ Transition metal ions, such as Fe, form broad absorption bands in a glass matrix through dd-electron transitions: 3+ It exhibits strong absorption in the 450-500nm (blue-green light region), Fe 2+ Charge transfer transitions occur in the 600-700nm (red-orange light region), while Mn 2+ The 6A1→4T1 transition (500-550nm) covers the mid-wavelength range. However, there are gaps in the absorption peaks of these endogenous ions (e.g., high reflectivity in the ultraviolet region below 400nm and the near-infrared region above 700nm), causing traditional steel slag microcrystalline plates to easily exhibit a grayish-brown hue. Therefore, Co in the colorant... 2+ with Ni 2+ Introduced at a mass ratio of 1:(3-4), its electronic properties precisely complement those of steel slag ions—Co 2+ The 4T1→4T2 transition produces a sharp absorption peak at 400-450nm, effectively filling the reflection gap in the ultraviolet-blue light region; while Ni 2+ The 3A2→3T1 transition broadens the absorption range at 700-800nm ​​and forms a continuous absorption band through crystal field splitting, suppressing the full-band reflectivity to below 5%, thus achieving the ultimate blackness of the microcrystalline substrate. The low addition amount (0.02-0.03%) of the colorant achieves efficient color development due to the presence of Mn in the steel slag. 2+ Sensitization effect of Mn 2+ The excited state injects electrons into Co through resonant energy transfer. 2+ This increases its light absorption efficiency by more than three times, while Ni 2+ with Fe 2+ The synergistic spin coupling of FeS prolongs the relaxation time and enhances the stability of photothermal conversion. In addition, the metallic luster of FeS and the light scattering effect of TiO2 synergistically endow the substrate with a deep, glossy black color.

[0034] The black steel slag microcrystalline plate provided by this invention has a steel slag particle size ≥ 40 mesh; the steel slag includes the following oxides in the following mass percentages: MgO 7-9%, Al2O3 4-6%, SiO2 16-18%, MnO 2-3%, CaO 43-45%, Fe2O3 14-16%, P2O5 1-2%, and the balance being other oxides.

[0035] The black steel slag microcrystalline plate provided by this invention has a bottom slag particle size ≥60 mesh; the bottom slag comprises the following oxides in the following mass percentages: MgO 0.3-0.7%, Al2O3 4-5%, SiO2 89-90%, CaO 0.3-0.6%, Fe2O3 0.5-1%, P2O5 1.5-2%, with the balance being other oxides. In a specific embodiment, the black steel slag microcrystalline plate is the grate ash produced by the fluidized bed incineration of sludge from a municipal wastewater treatment plant in Shanghai.

[0036] The black steel slag microcrystalline substrate provided by this invention contains porous graphene microflora with a 3D porous folded structure and a specific surface area ≥220 m². 2 / g, density is 40-48mg / cm³ 3 .

[0037] Preparation method of black steel slag microcrystalline substrate

[0038] The second aspect of this invention provides a method for preparing black steel slag microcrystalline plates, comprising the following steps: The material is melted in the main melting pool, flow channel, riser, and feed channel of an all-electric melting furnace, then flows out through the outlet at the end of the feed channel, and is pressed into plates by a rolling mill. The plates are then crystallized, cut, and polished to obtain black steel slag microcrystalline plates. The materials consist of steel slag, bottom slag, soda ash, sodium sulfide, sodium fluorosilicate, barium titanate, porous graphene micron flowers, cerium fluoride, sodium pyrophosphate, and a colorant, weighed according to a specified mass percentage ratio.

[0039] This invention constructs a gradient and precisely controllable reducing atmosphere regulation mechanism through the synergistic effect of a multi-stage reduction system and novel carbon-based materials, effectively solving the contradiction between the stability and safety of the reducing atmosphere during the melting of steel slag microcrystalline plates. In the main molten pool, flow channel, and ascending channel during the melting process, the FeO contained in the steel slag itself acts as a natural reducing agent, gradually releasing its reducing power at high temperatures of 1400-1500℃. Specifically, FeO undergoes the reaction FeO→Fe + [O] provides active oxygen capture capability. This reduction system, dominated by endogenous components of steel slag, fully utilizes the characteristics of solid waste resources while avoiding the increased cost caused by excessive addition of exogenous reducing agents. At this point, porous graphene micro-flowers, with their 3D porous folded structure, interact with Fe in the melt through oxygen-containing functional groups adsorbed on their surface. 3+ Coordination occurs, forming a dynamic electron transport channel that helps stabilize the redox potential within a controlled range, ensuring that sulfur preferentially combines with iron to form FeS rather than SO2 gas. When the melt enters the feed channel, the reducing power of the steel slag weakens due to FeO consumption. At this point, the unique advantages of porous graphene micron flowers become apparent. The sp2 hybrid carbon framework embedded in its 3D porous folded structure gradually releases delocalized electrons at high temperatures, continuously providing a mild reducing atmosphere through surface defect sites, thus reducing residual Fe.3+ Reduced to Fe 2+ Simultaneously, S is selectively adsorbed through edge active sites. 2- Ions inhibit the secondary formation of SO2 in the later stages. This synergistic mechanism of "front-end steel slag dominance - back-end graphene relay" ensures that the reduction intensity throughout the entire process is always controlled within the critical threshold, avoiding the Fe reduction caused by excessive carbon powder in traditional processes. 3+ Excessive reduction to elemental iron further enhances sulfur fixation efficiency, significantly reducing the bubble defect rate of the sheet metal. This reduction control strategy, based on solid waste characteristic analysis and advanced material design, provides an innovative solution for the high-value utilization of industrial solid waste.

[0040] This invention constructs an F-FeS-TiO2 composite nucleating agent system, achieving low-temperature, high-efficiency crystallization and precise microstructure control of steel slag microcrystalline plates through the synergistic effect of multiple components. Its core mechanism lies in the phased activation of the properties of different nucleating agents, forming a multi-scale nucleation-growth network. In the initial stage of material melting (900-1100℃), sodium fluorosilicate decomposes upon heating to generate active F... - On the one hand, by replacing the O in the silicon-oxygen network 2- The formation of ≡Si-F bonds significantly reduces melt viscosity and promotes ion migration; on the other hand, F - With Ca in steel slag 2+ The resulting CaF2 microcrystals act as primary nuclei, anchoring the sodium sulfide within the glass matrix. Simultaneously, sodium sulfide releases sulfur under a reducing atmosphere. 2- The FeS reacts with FeO in steel slag to form FeS. Its cubic crystal structure has a low lattice mismatch with the subsequently precipitated main crystalline phase (such as diopside), making it suitable as a heterogeneous nucleation substrate. This significantly reduces the crystallization activation energy of the plate system of this invention and significantly increases the nucleation density. When the material melting temperature is between 700-850℃, TiO2 produced by the decomposition of barium titanate begins to play a role. TiO2 is incorporated into the glass network in the form of [TiO6] octahedra, and its high field strength induces surrounding cations (such as Ca). 2+ Mg 2+ The enrichment of CaF2 and FeS crystal nuclei leads to localized compositional fluctuations, triggering a phase separation-crystallization coupling effect. At this point, TiO2 nanoclusters adsorb onto the surface of the previously formed CaF2 and FeS crystal nuclei, forming a "core-shell" composite nucleus structure. This significantly reduces the interfacial energy, promoting the growth of the main crystalline phase in a discontinuous, jumping mode, ultimately resulting in a microcrystalline structure with uniform grain size and high crystallinity. This gradient activation mechanism of the composite nucleus allows the thermal expansion coefficient of the board material to match that of building substrates, resulting in high flexural strength and meeting the demands of high-end integrated decorative and structural applications. This "solid waste-derived - multiphase synergy" nucleus design strategy provides an innovative path for preparing high-performance microcrystalline materials from industrial solid waste.

[0041] This invention achieves a breakthrough improvement in the visual aesthetics of steel slag microcrystalline plates through the innovative design of a Ba-Ce-Na composite system. Its core mechanism lies in the synergistic regulation of the optical properties of the glass matrix and the crystal interface effect by multiple valence elements. Barium titanate decomposes into BaO and TiO2 during high-temperature melting, with Ba... 2+ As a highly polarizable cation participating in the glass network, cerium fluoride combines with non-bridging oxygen in silicon-oxygen tetrahedra to form [Ba-O-Si] structural units, significantly increasing the refractive index of the glass phase and imparting a metallic-like luster to the surface of the plate; simultaneously, cerium fluoride releases Ce... 3+ / Ce 4+ Ions, through dynamic valence state transitions, form localized electron cloud rearrangements at the glass-microcrystal interface, selectively absorbing the 500-600nm wavelength range of visible light, and reacting with the complementary colorant Co. 2+ / Ni 2+ The complementary absorption peaks of the dd transition (400-500nm blue light, 600-700nm red light) suppress the reflectance spectrum of the board to below 5% across the entire wavelength range, resulting in a deep, glossy black color and achieving the visual effect of high-end black diamond materials. The sodium carbonate introduced by soda ash... + It optimizes hue uniformity through a dual action: on the one hand, it acts as a network modifier to reduce melt viscosity and promote Ce... 3+ Co 2+ Ni 2+ The uniform distribution of plasma in the glass phase avoids the color spot defects caused by ion segregation in traditional processes; on the other hand, Na + With Ce 4+ Forming a [Na-O-Ce] charge-compensating structure to stabilize Ce 3+ / Ce 4+ The redox balance is maintained to prevent Ce from being exposed to high temperatures. 3+ Oxidation causes a shift in yellowish-brown hue. Additionally, Ba... 2+ The high field strength characteristics induce the main crystal phase (such as diopside) to preferentially grow along the (110) crystal plane, forming parallel-arranged plate-like microcrystals. The regular interface forms a periodic refractive index difference with the glass phase, producing a soft diffuse reflection effect, further weakening the surface glare, and making the black texture more warm and delicate.

[0042] In the preparation method of the black steel slag microcrystalline plate provided by the present invention, the temperature of the main molten pool is room temperature - 1550℃, and the residence time is 11h. The surface temperature of the material in the upper part of the main molten pool is ≤200℃.

[0043] In the preparation method of the black steel slag microcrystalline plate provided by the present invention, the temperature of the flow hole is 1550-1500℃ and the residence time is 40min.

[0044] In the preparation method of the black steel slag microcrystalline plate provided by the present invention, the temperature of the rising channel is 1500-1450℃ and the residence time is 2h.

[0045] In the preparation method of the black steel slag microcrystalline plate provided by the present invention, the temperature of the material channel is 1450-1370℃ and the residence time is 3.5h.

[0046] In the preparation method of the black steel slag microcrystalline plate provided by the present invention, the thickness of the plate is 12-20mm.

[0047] In the preparation method of the black steel slag microcrystalline plate provided by this invention, the crystallization temperature is divided into eight temperature control sections: the first, second, third, fourth, fifth, sixth, seventh, and eighth. These eight temperature control sections represent the optimal crystallization regime, which is beneficial for improving the plate's performance and aesthetic appeal. The first temperature control section is 600-680℃, with a uniform heating rate for 30 minutes; the second temperature control section is 680-760℃, with a uniform heating rate for 120 minutes; the third temperature control section is 760-820℃, with a uniform heating rate for 50 minutes; the fourth temperature control section is 820-860℃, with a uniform heating rate for 80 minutes; the fifth temperature control section is 860-820℃, with a uniform heating rate for 50 minutes; the sixth temperature control section is 820-860℃, with a uniform heating rate for 80 minutes; the seventh temperature control section is 860-820℃, with a uniform heating rate for 80 minutes; the fifth temperature control section is 860-820℃, with a uniform heating rate for 80 minutes; the seventh temperature control section is 860-820℃, with a uniform heating rate for 80 minutes; the eighth ... ninth temperature control section is 860-820℃, with a uniform heating rate for 80 minutes; the tenth temperature control section is 860-820℃, with a uniform heating rate for 80 minutes; the tenth temperature control section is 860-820℃, with a uniform heating rate for 8 The temperature remains constant at 0℃ for 40 minutes; the sixth temperature control section: 860-650℃, with uniform cooling for 60 minutes; the seventh temperature control section: 650-500℃, with uniform cooling for 100 minutes; the eighth temperature control section: 500-70℃, with uniform cooling for 100 minutes; the temperature field uniformity of each temperature control section is ±5℃, and the temperature control accuracy is ±1℃.

[0048] In the preparation method of the black steel slag microcrystalline plate provided by the present invention, the plate is glossy black after grinding and polishing.

[0049] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be specifically described below in conjunction with embodiments.

[0050] In the following examples, unless otherwise stated, all reactants are commercially available products.

[0051] Unless otherwise specified, the purity of each product in each embodiment of the present invention exceeds 98%.

[0052] The following provides a specific embodiment of the present invention: a black steel slag microcrystalline plate and its preparation method.

[0053] Examples 1-6

[0054] The raw material composition mass fractions of the black steel slag microcrystalline plates of Examples 1-6 are shown in Table 1.

[0055] Table 1. Raw material composition of Examples 1-6, wt%

[0056]

[0057] Preparation methods of black steel slag microcrystalline plates in Examples 1-6:

[0058] Main molten pool: residence time 11h between room temperature and 1550℃; flow channel: residence time 40min between 1550-1500℃; ascender: residence time 2h between 1500-1450℃; feed channel: residence time 3.5h between 1450-1370℃; the melt at 1370℃ flows horizontally out through the outlet at the end of the feed channel and is pressed into a sheet by a calender; the surface temperature of the material in the upper part of the main molten pool is ≤200℃. The crystallization process of the microcrystalline sheet after calendering adopts a one-step process, and the thermal regime of the crystallization process is as follows:

[0059] First temperature control section: 600-680℃, uniform temperature increase, heating time 30min;

[0060] Second temperature control section: 680-760℃, uniform temperature increase, heating time 120min;

[0061] The third temperature control section: the temperature rises at a constant rate between 760-820℃, and the heating time is 50 minutes.

[0062] Fourth temperature control section: 820-860℃, uniform temperature increase, heating time 80min;

[0063] Fifth temperature control section: 860℃ remains constant, holding time is 40 minutes;

[0064] 6th temperature control section: between 860-650℃, uniform cooling rate, cooling time 60min;

[0065] 7th temperature control section: 650-500℃, uniform cooling rate, cooling time is 100min;

[0066] Section 8: Temperature control: The temperature is uniformly reduced between 500-70℃ for 100 minutes. After the temperature drops to 70℃ and the material exits the crystallization furnace, it is cut into large plates and cooled to room temperature before entering the polishing section. The microcrystalline plates are glossy black after polishing.

[0067] The raw material composition of a black steel slag microcrystalline plate, as shown in Table 2, is described in Comparative Examples 1-5. The preparation method is the same as that in Examples 1-5.

[0068] Table 2. Raw material composition of Comparative Examples 1-5, wt%.

[0069]

[0070] The microcrystalline glass sheets of this invention were tested for key indicators according to the methods specified in the industry standard "JC / T 872-2019 Microcrystalline Glass for Architectural Decoration". Qualified products meet the requirements of "JC / T 872-2019 Microcrystalline Glass for Architectural Decoration". The color of the sheets was determined by visual comparison; after crystallization, the entire sheet should exhibit crystallization without edge collapse. Test results are shown in Table 3.

[0071] Table 3 Physical properties of Examples 1-6 and Comparative Examples 1-5

[0072]

[0073] In Comparative Example 1, the sodium sulfide content was low at 0.2%, resulting in a reduction of sulfur (S) in the glass matrix. This led to a decrease in the degree of crystallization in the microcrystalline substrate. Although the glass matrix crystallized overall, edge collapse occurred after crystallization. Test results showed a Mohs hardness of 4.8 and an abrasion resistance of 5.3 × 10⁻¹ g / cm². 2 Other strength indicators also showed a significant decline, and the product quality failed to meet the standards.

[0074] In Comparative Example 2, the barium titanate content was low at 0.2%, resulting in the absence of Ba and Ti in the glass matrix. This significantly degraded the visual appeal of the microcrystalline substrate and slightly weakened the degree of crystallization. Although the surface color remained black, the reduced brightness affected the visual appeal and was detrimental to sales.

[0075] Comparative Example 3 lacked porous graphene micron flowers, making it difficult to maintain a reducing atmosphere in the melt. This resulted in a significant decrease in the glass's crystallization ability and the formation of numerous small sulfur bubbles within the plate. Test results showed a Mohs hardness of 4.2, shallow scratches in the scratch resistance test, small cracks in the rapid cooling and heating resistance test, and an abrasion resistance of 6.7 × 10⁻¹ g / cm². 2 Impact toughness is 1.1 kJ / m 2 The analysis revealed that after crystallization, edge collapse occurred, and the surface color was dark blue-black, indicating that the product quality failed to meet the standards.

[0076] Comparative Example 4, which does not contain cerium fluoride, showed little change in strength indicators, but its surface color and brightness were reduced.

[0077] Comparative Example 5 contained no complementary colorant, and its strength index remained unchanged, but its surface color was dark blue.

[0078] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A black steel slag microcrystalline plate, characterized in that, The raw materials of the black steel slag microcrystalline plate, by mass percentage, include: steel slag 48-52%, bottom slag 33-37%, soda ash 8.5-10.5%, sodium sulfide 0.5-1%, sodium fluorosilicate 3-3.5%, barium titanate 0.6-0.8%, porous graphene micron flowers 0.04-0.06%, cerium fluoride 0.2-0.3%, sodium pyrophosphate 0.6-0.8%, and colorant 0.02-0.03%.

2. The black steel slag microcrystalline plate as described in claim 1, characterized in that, The raw materials of the black steel slag microcrystalline plate, by weight percentage, include: 50% steel slag, 35% bottom slag, 9.4% soda ash, 0.7% sodium sulfide, 3.2% sodium fluorosilicate, 0.68% barium titanate, 0.05% porous graphene micron flowers, 0.25% cerium fluoride, 0.7% sodium pyrophosphate, and 0.02% colorant.

3. The black steel slag microcrystalline plate as described in claim 1 or 2, characterized in that, The bottom ash is the grate ash produced by the fluidized bed incineration of sludge in a municipal wastewater treatment plant.

4. The black steel slag microcrystalline plate as described in claim 1 or 2, characterized in that, The complementary colorant includes cobalt oxide and nickel oxide.

5. The black steel slag microcrystalline plate as described in claim 4, characterized in that, The mass ratio of cobalt oxide to nickel oxide is 1:(3-4).

6. The black steel slag microcrystalline plate as described in claim 1 or 2, characterized in that, Includes one or more of the following features: A1) The particle size of the steel slag is ≥40 mesh; A2) The steel slag comprises the following oxides in the following mass percentages: MgO 7-9%, Al2O3 4-6%, SiO2 16-18%. MnO 2-3%, CaO 43-45%, Fe2O3 14-16%, P2O5 1-2%, balance other oxides; A3) The particle size of the bottom slag is ≥60 mesh; A4) The bottom slag includes the following oxides in the following mass percentages: MgO 0.3-0.7%, Al2O3 4-5%, SiO2 89-90%, CaO 0.3-0.6%, Fe2O3 0.5-1%, P2O5 1.5-2%, with the balance being other oxides.

7. The black steel slag microcrystalline plate as described in claim 1 or 2, characterized in that, The porous graphene microflora has a 3D porous folded structure with a specific surface area ≥220m². 2 / g, density is 40-48mg / cm³ 3 .

8. The method for preparing black steel slag microcrystalline plates according to any one of claims 1-7, characterized in that, The process includes the following steps: After the material is melted in the main melting pool, flow channel, rising channel and material channel of the all-electric melting furnace, it flows out through the discharge port at the end of the material channel and is pressed into a plate by a rolling mill. After crystallization, cutting and polishing, the plate is used to obtain black steel slag microcrystalline plate.

9. The method for preparing the black steel slag microcrystalline plate as described in claim 8, characterized in that, Includes one or more of the following features: B1) The temperature of the main molten pool is room temperature - 1550℃, and the residence time is 11h; B2) The surface temperature of the material in the upper part of the main molten pool is ≤200℃; B3) The temperature of the flow cavity is 1550-1500℃, and the residence time is 40min; B4) The temperature of the ascending channel is 1500-1450℃, and the residence time is 2 hours; B5) The temperature of the material channel is 1450-1370℃, and the residence time is 3.5h; B6) The thickness of the plate is 12-20mm; B7) The crystallization temperature is divided into the first temperature control segment, the second temperature control segment, the third temperature control segment, the fourth temperature control segment, the fifth temperature control segment, the sixth temperature control segment, the seventh temperature control segment, and the eighth temperature control segment; The plate described in B8) is glossy black after grinding and polishing.

10. The method for preparing the black steel slag microcrystalline plate as described in claim 9, characterized in that, Includes one or more of the following features: B71) The first temperature control section: between 600-680℃, the temperature is increased at a uniform rate, and the heating time is 30 minutes; B72) The second temperature control section: between 680-760℃, the temperature is increased at a uniform rate, and the heating time is 120min; The third temperature control section (B73) is as follows: the temperature rises at a uniform rate between 760-820℃ for 50 minutes. B74) The fourth temperature control section: between 820-860℃, the temperature is increased at a uniform rate, and the heating time is 80min; B75) The fifth temperature control section: 860℃ remains constant, and the holding time is 40 minutes; B76) The sixth temperature control section: between 860-650℃, the temperature drops at a uniform rate for 60 minutes; B77) The 7th temperature control section: between 650-500℃, the temperature drops at a uniform rate for 100 minutes; B78) The 8th temperature control section: between 500-70℃, the temperature drops at a uniform rate for 100 minutes; (B79) The temperature field uniformity of each temperature control section is ±5℃, and the temperature control accuracy is ±1℃.

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