A method for co-melting and vitrification of electroplating sludge and coal gasification slag and efficient recovery of metal alloys

Abstract

This application provides a method for the co-melting vitrification of electroplating sludge and coal gasification slag and the efficient recovery of metal alloys. The method comprises: uniformly mixing dried coal gasification slag and electroplating sludge, melting, cooling, and separating to obtain a glass product and an alloy; the mass ratio of coal gasification slag to electroplating sludge is 0.5-2:1; the melting time is 30-150 min; and the viscosity of the molten system is controlled at 0.83-67.22 Pa·s. This method has low raw material costs and achieves vitrification of the eutectic system and alloy recovery of the metal, with a high alloy recovery rate. This application also provides a microcrystalline glass, obtained by heat treatment of the glass product prepared by the above method. The resulting microcrystalline glass has high Vickers hardness, low water absorption, and good resistance to acid and alkali corrosion.

Description

Technical Field

[0001] This application relates to the field of waste resource utilization technology, and in particular to a method for the synergistic melting and vitrification of electroplating sludge and coal gasification slag and the efficient recovery of metal alloys. Background Technology

[0002] With the rapid development of the electronics, automotive, and aerospace industries, electroplating has become a widely used supporting technology. However, the treatment of electroplating wastewater generates a large amount of electroplating sludge (ES). Due to its complex composition, high heavy metal content, and ecotoxicity, ES has been classified as a globally hazardous waste. Improper treatment can pose certain risks to the ecological environment and human health. On the other hand, the copper, nickel, and other metals in electroplating sludge are often of higher grade than those in primary metal ores, possessing high secondary resource value. Therefore, effective methods are needed for the resource-based treatment of electroplating sludge.

[0003] Currently, the main methods for the disposal and resource utilization of electroplating sludge include solidification / stabilization and metal recovery. Solidification / stabilization can effectively reduce the risk of metal leaching and migration, but this method results in metal resource loss and increases waste volume. Resource utilization pathways mainly include wet leaching, bioleaching, and material utilization. Wet leaching utilizes the high metal concentration and easy leaching characteristics of electroplating sludge to achieve efficient metal extraction through chemical reagents, but it also generates secondary pollutants such as waste liquid and residue that require further treatment. Bioleaching is environmentally friendly, but the treatment cycle is long, and microbial growth has strict requirements for temperature and pH conditions. Compared with traditional methods, melting treatment is considered a more advantageous disposal method because it can achieve efficient volume reduction, detoxification, and improved resource utilization potential. In the vitrification process, thermal reduction control can achieve simultaneous solidification and stabilization of metal resources through separation and recovery. Existing technologies have achieved vitrification of electroplating sludge at 1450 °C by adding limestone, crushed glass, and reduced carbon. Cu, Ni, and Fe are effectively recovered through the reduction process, while the remaining metals are solidified in a stable form within the glass matrix. Summary of the Invention

[0004] To solve at least one of the above-mentioned technical problems, this application provides a method for the synergistic melting and vitrification of electroplating sludge and coal gasification slag and the efficient recovery of metal alloys, comprising: mixing dried coal gasification slag and electroplating sludge evenly, melting, cooling, and separating to obtain glass products and alloys;

[0005] The mass ratio of coal gasification slag to electroplating sludge is 0.5-2:1; the melting time is 30-150 min.

[0006] The viscosity of the molten system was controlled to be 2.9-21.8 Pa·s;

[0007] Based on the mass of the coal gasification slag as 100%, the coal gasification slag includes 17-20 wt% CaO, 41-44 wt% SiO2, 16-19 wt% Al2O3, 2-4 wt% Na2O, 12-15 wt% Fe2O3, and 6-7.5 wt% C;

[0008] Based on the mass of electroplating sludge as 100%, the coal gasification slag includes 33-36 wt% CaO, 1.5-4 wt% SiO2, 1.5-4 wt% Al2O3, 1.5-4 wt% Na2O, 4-7 wt% Fe2O3, and 3-5 wt% C.

[0009] The high CaO content of electroplating sludge results in a high melting temperature when melted alone. Introducing SiO2 and Al2O3 can regulate the CaO-SiO2-Al2O3 phase equilibrium, thereby lowering the melting temperature and reducing energy consumption. Studies show that SiO2 forms the basic framework for glass matrix formation and plays a crucial role in the formation of amorphous structures during melting. CaO is another key component, capable of regulating the melting process through interactions with silicon and aluminum phases. Coal gasification slag (CGS) is a typical byproduct of the coal chemical industry, rich in SiO2 and Al2O3, and also contains a certain amount of residual carbon. Introducing CGS and B2O3 into the electroplating sludge melting system can lower the melting point through chemical regulation, thus promoting the glassization of the electroplating sludge. Furthermore, the residual carbon in CGS can play a thermal reduction role during melting, which is beneficial for the synergistic glassization of electroplating sludge and CGS and the recovery of metal alloys, achieving both environmental and economic benefits.

[0010] Both electroplating sludge and coal gasification slag require the addition of additives and melting to obtain glass. This application melts electroplating sludge and coal gasification slag to obtain glass products and alloy products, which is low-cost. The preparation of glass products and alloy products from electroplating sludge and coal gasification slag has a synergistic effect in improving the performance of glass products and metal recovery efficiency.

[0011] Preferably, the mass ratio of coal gasification slag to electroplating sludge is 0.75-1.25:1.

[0012] By optimizing the mass ratio of coal gasification slag to electroplating sludge through the technical solution of this invention, the relative content of NBO can be increased, promoting the conversion of BO to NBO to achieve depolymerization of the melt network. This depolymerization process transforms the structure from long-range order to disorder, resulting in an amorphous glass product and enhanced melt flow characteristics.

[0013] Preferably, the viscosity of the molten system is controlled to be 2.9-6.1 Pa·s.

[0014] Preferably, the melting time is 80-95 min.

[0015] Preferably, B2O3 is also added to the system, and the mass of B2O3 added is 2.5-10% of the total mass of coal gasification slag and electroplating sludge.

[0016] Preferably, B2O3 is also added to the system, and the mass of B2O3 added is 7.5% of the total mass of coal gasification slag and electroplating sludge.

[0017] Preferably, 2.5-4.5% of the total mass of coal gasification slag and electroplating sludge is added before melting, and another 2.5-4.5% of the total mass of coal gasification slag and electroplating sludge is added after melting for 20 minutes.

[0018] Preferably, 3.5% of the total mass of coal gasification slag and electroplating sludge B2O3 is added before melting, and 4% of the total mass of coal gasification slag and electroplating sludge B2O3 is added after melting for 20 minutes.

[0019] In the technical solution of this application, the separation mechanism of electroplating sludge, coal gasification slag, and B2O3 through synergistic melting, vitrification, and simultaneous metal alloying is as follows: Figure 1 As shown, the co-melting system of electroplating sludge and coal gasification slag generates highly miscible metal alloy products through carbothermic reduction. At the same time, under the regulation of multiple chemical species such as CaO, AlO2 and B2O3, the depolymerization of the complex silicon-oxygen network structure is promoted, the melting characteristics of the melt are enhanced and the melt viscosity is reduced, thereby achieving efficient separation of the alloy phase.

[0020] In a second aspect of the invention, this application also provides a microcrystalline glass, which is obtained by heat treatment of a glass product prepared by the method described in the first aspect of the invention.

[0021] Preferably, the heat treatment temperature is 750°C and the time is 1.5-2.5h.

[0022] The inventive concept of this application is as follows:

[0023] Co-melting electroplating sludge and coal gasification slag promoted the transformation of the BO network to NBO in the melt, thereby reducing its degree of polymerization. Under the thermal reduction effect of residual carbon in the coal gasification slag, the main metals Cu, Ni, and Fe in the system were reduced and formed a highly miscible solid solution alloy. The enhanced melt fluidity of the molten system promoted the migration, aggregation, and separation of the alloy phases, thus simultaneously achieving the glassization of the eutectic system and the alloying and recycling of the metals.

[0024] By introducing exogenous active species B2O3 into a system composed of electroplating sludge and coal gasification slag, the complex silicate structural units (Q) are further promoted.3 and Q 4 Towards simple structural units (Q) 0 and Q 1 The transformation of the glass enhances the melting effect of the melt and achieves vitrification.

[0025] Electroplating sludge and coal gasification slag were co-melted, and a small amount of exogenous active species B2O3 was introduced to construct a multi-chemical species co-melting, vitrification, and simultaneous metal alloying separation system with electroplating sludge and coal gasification slag as the main components.

[0026] In addition, high-performance microcrystalline glass was successfully prepared using glass products, providing a feasible solution for the co-processing of electroplating sludge and coal gasification slag.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. This application provides a method for the synergistic vitrification and efficient recovery of metal alloys from electroplating sludge and coal gasification slag. Over 90% of the raw materials utilize industrial waste, resulting in low cost. Furthermore, it achieves vitrification of the eutectic system and alloy recovery of the metal, with a high alloy recovery rate. Further, by introducing exogenous active species B2O3 into the system composed of electroplating sludge and coal gasification slag, it further promotes the complex silicate structural unit (Q... 3 and Q 4 Towards simple structural units (Q) 0 and Q 1 The transformation of the glass enhances the melting effect of the melt and achieves vitrification.

[0029] 2. This application provides a microcrystalline glass, obtained by heat treatment of the glass product prepared by the above method. The residual heavy metals Cu, Ni, Zn, and Cr in the obtained microcrystalline glass are stably solidified in the glass matrix, and their heavy metal leaching toxicity is far below the limits specified in the "Technical Requirements for Vitrification Products of Solid Waste" (GB / T 41015-2021). Its Vickers hardness, water absorption, acid corrosion resistance, and alkali corrosion resistance are 6.91 GPa, 0.04%, 99.61%, and 99.62%, respectively. Attached Figure Description

[0030] Figure 1 A schematic diagram illustrating the synergistic demelting and simultaneous glassization and metal alloying separation mechanism of electroplating sludge and coal gasification slag;

[0031] Figure 2 Photos of electroplating sludge and coal gasification slag;

[0032] in, Figure 2 (a) is electroplating sludge. Figure 2 (b) is coal gasification slag;

[0033] Figure 3 XRD patterns of electroplating sludge and coal gasification slag samples;

[0034] in, Figure 3 (a) is the XRD pattern of electroplating sludge. Figure 3 (b) is the XRD pattern of coal gasification slag;

[0035] Figure 4 A comparative graph showing the effects of mixing coal gasification slag (CGS) and electroplating sludge (ES) at different mass ratios on the efficiency of glass product and metal recovery.

[0036] in, Figure 4 (a) XRD patterns of glass products prepared by mixing coal gasification slag (CGS) and electroplating sludge (ES) at different mass ratios; Figure 4 (b) is a graph showing the comparison of the recovery efficiency of alloys prepared by mixing coal gasification slag (CGS) and electroplating sludge (ES) at different mass ratios;

[0037] Figure 5 The analysis results are for glass products obtained by mixing coal gasification slag (CGS) and electroplating sludge (ES) at different mass ratios;

[0038] in, Figure 5 (a) is the O 1s high-resolution XPS spectrum of the corresponding glass product. Figure 5 (b) shows the O 1s spectrum fitting results for the corresponding glass product; Figure 5 (c) represents the NBO content of the corresponding glass product;

[0039] Figure 6 The analytical results are for glass products when the mass ratio of coal gasification slag to electroplating sludge is 0.5:1, 0.75:1 and 1:1, respectively.

[0040] in, Figure 6 (a) High-resolution XPS spectra of Al 2p of glass products when the mass ratio of coal gasification slag to electroplating sludge is 0.5:1, 0.75:1 and 1:1, respectively; Figure 6 (b) The [AlO4] content of the glass products when the mass ratio of coal gasification slag to electroplating sludge is 0.5:1, 0.75:1 and 1:1, respectively;

[0041] Figure 7 A comparative graph showing the effect of different viscosities (2.9 Pa·s, 3.8 Pa·s, 6.1 Pa·s, 12.8 Pa·s, 21.8 Pa·s) on metal recovery efficiency;

[0042] Figure 8 A comparative graph showing the effects of adding different amounts of B2O3 on glass products and metal recovery efficiency.

[0043] in, Figure 8 (a) XRD patterns of glass products prepared under conditions where the added mass of B2O3 is 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge. Figure 8 (b) is a comparison of the recovery efficiency of alloys prepared under the conditions of adding B2O3 at 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge.

[0044] Figure 9 FTIR spectra and Gaussian fitting results of glass products prepared under the conditions of adding B2O3 at 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge.

[0045] in, Figure 9 (a) FTIR spectra of glass products prepared under conditions where the added mass of B2O3 is 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge. Figure 9 (b) shows the Gaussian fitting results without adding B2O3; Figure 9 (c) Gaussian fitting results with 2.5 wt% B2O3 added; Figure 9 (d) shows the Gaussian fitting results with 5 wt% B2O3 added; Figure 9 (e) Gaussian fitting results with 7.5 wt% B2O3 added; Figure 9 (f) shows the Gaussian fitting results with 10wt% B2O3 added;

[0046] Figure 10 The effect of adding B2O3 at 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge on the properties of glass products prepared.

[0047] in, Figure 10 (a) The addition mass of B2O3 is 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge, respectively, relative to Q. 0 Q 1 Q 2 Q 3 and Q 4 The effect of the percentage of structural units is shown in the diagram. Figure 10 (b) is a graph showing the effect of B2O3 addition on the amorphous content of glass products;

[0048] Figure 11 SEM-EDS analysis of the alloy products;

[0049] in, Figure 11 (a) shows three typical areas in the alloy: light color (1), dark color (2), and black color (3); Figure 11 (b)- Figure 11 (e) is an EDS surface scan analysis; Figure 11 (f)- Figure 11 (h) represents the point analysis results;

[0050] Figure 12 SEM-EDS analysis of alloy products obtained by melting mixtures with and without B2O3 and with 7.5% B2O3;

[0051] in, Figure 12 (a) SEM-EDS analysis of the alloy product obtained after melting the mixture without the addition of B2O3; Figure 12 (b) SEM-EDS analysis of the alloy product obtained after melting the mixture with 7.5% B2O3 added;

[0052] Figure 13 A comparative graph showing the effects of melting time on glass products and metal recovery efficiency;

[0053] in, Figure 13 (a) XRD patterns of glass products prepared at different melting times; Figure 13 (b) A graph showing the comparison of the recovery efficiency of alloys prepared at different melting times;

[0054] Figure 14 The distribution of heavy metal speciation in the original sample (the original mixed sample before melting) and the glass product;

[0055] in, Figure 14 (a) shows the speciation of heavy metals in the original sample (the original mixed sample before melting); Figure 14 (b) The speciation of heavy metals in the obtained glass product;

[0056] Figure 15 The DSC curves of the glass products and the detection graphs of the glass-ceramic are shown.

[0057] in, Figure 15 (a) shows the DSC curves of the vitrified products. Figure 15 (b) XRD patterns of vitrification products and glass-ceramics; Figure 15 (c) shows the crystal phase distribution of the glass-ceramic. Detailed Implementation

[0058] The present invention will be further described below with reference to specific embodiments. However, the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified, specific conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the methods used are conventional methods known in the art, and the consumables and reagents used are commercially available. Unless otherwise stated, the technical and scientific terms used herein have the same meaning as those familiar with the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be applied to the present invention.

[0059] The electroplating sludge sample was taken from Chang'an Electroplating Industrial Park in Dongguan, Guangdong, and the coal gasification slag sample was taken from Ningdong Coal Gasification Base in Ningxia.

[0060] Electroplating sludge (ES) samples were all in the form of fine granular powder. After drying at 105 °C for 12 h, they were mixed evenly to obtain electroplating sludge, which was then stored in sealed bags for later use. Coal gasification slag (CGS) samples were hard and coarse-grained. After drying at 105 °C for 12 h, they were processed using a planetary ball mill, followed by sieving to obtain coal gasification slag, which was then sealed and stored for later use. Photos of the electroplating sludge and coal gasification slag are shown below. Figure 2 As shown. Among them, Figure 2 (a) is electroplating sludge. Figure 2 (b) is coal gasification slag.

[0061] The chemical composition of electroplating sludge and coal gasification slag was analyzed using XRF and carbon-sulfur analyzers, and the content of relevant metal elements was determined using ICP-OES. The relevant data are shown in Tables 1 and 2.

[0062] Table 1. Chemical composition (mass percentage) of different samples (unit: %)

[0063]

[0064] Table 2. Main heavy metal content (mass percentage) of different samples (unit: mg / kg)

[0065]

[0066] The XRD patterns of the electroplating sludge and coal gasification slag samples after drying, ball milling, and sieving pretreatment are shown below. Figure 3 As shown, where, Figure 3 (a) is the XRD pattern of electroplating sludge. Figure 3 (b) shows the XRD pattern of the coal gasification slag; from Figure 3It can be seen that there are no obvious metallic crystalline phases in the electroplating sludge; its main phases are calcium-containing phases CaSO4·2H2O (PDF#33-0311), CaSO4 (PDF#47-0157), and CaCO3 (PDF#47-1743). The coal gasification slag sample is in an amorphous glassy state, and apart from the weak crystallization peaks of SiO2 (PDF#47-1300) and C (PDF#06-0675), no other obvious crystalline phases were observed.

[0067] The methods for measuring and calculating the recovery rate of metals (Cu, Ni, Fe) are as follows:

[0068] Acid digestion was used to determine the heavy metal content of solid samples. The specific steps were as follows: Approximately 0.1 g of solid sample was weighed and placed in a 50 mL polytetrafluoroethylene (PTFE) digestion tube. Then, 10 mL of HNO3, 5 mL of HClO4, and 10 mL of HF were added sequentially. The digestion tube was then sealed and placed in a graphite digester. The temperature was raised to 195 °C for 30 min and maintained at 195 °C for 270 min. After digestion, the state of the digest was observed: if there was no remaining solid in the solution and the color was colorless and transparent or light yellow, the digestion was complete; if not, HNO3, HClO4, and HF were added again in the same proportion, and the same digestion procedure was used until the solution was clear and free of solid residue. After complete digestion, the resulting digest was cooled to room temperature, filtered through a 0.45 μm filter membrane, transferred to a 50 mL volumetric flask, and diluted to volume with deionized water. Finally, the obtained sample solution was placed into a 50 ml centrifuge tube, sealed, and stored for the determination of relevant heavy metal content.

[0069] The recovery rates of the metals (Cu, Ni, Fe) are calculated as shown in Equation 1:

[0070]

[0071] in, m 1 and m 3 The values ​​are the mass (g) of the original sample and the alloy product, respectively. c 1 and c 3 The values ​​(mg / kg) represent the content of Cu, Ni, and Fe metals in the original sample and the alloy product, respectively.

[0072] Example 1

[0073] Example 1 investigated the effects of coal gasification slag (CGS) and electroplating sludge (ES) at different mass ratios on the vitrification transition of glass products and the efficiency of metal separation and recovery.

[0074] Coal gasification slag (CGS) and electroplating sludge (ES) were mixed evenly at different mass ratios (0.5:1, 0.75:1, 1:1, 1.25:1, 1.5:1, 1.75:1 and 2:1) to obtain mixtures of coal gasification slag and electroplating sludge with different mass ratios. The mixtures were placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt them. The melt viscosity was maintained at 3.8 Pa·s and the melting time was 90 min. The mixtures were then naturally cooled to room temperature and crushed and separated to obtain alloy products and glass products.

[0075] XRD patterns of glass products obtained under different mixing ratios (coal gasification slag (CGS) and electroplating sludge (ES) mixed at different mass ratios (0.5:1, 0.75:1, 1:1, 1.25:1, 1.5:1, 1.75:1, and 2:1)) are shown below. Figure 4 As shown in (a), when the mass ratio of gasification slag to electroplating sludge is 0.5:1, the high CaO content in the system leads to the appearance of various calcium-containing crystalline phases in the glass product, such as Ca2Fe2O5 (PDF#38-0408), CaSO3 (PDF#36-0530), CaS (PDF#08-0464), and CaFeO2 (PDF#21-0917). Increasing the proportion of gasification slag to the mass ratio of gasification slag to electroplating sludge to 0.75:1, 1:1, and 1.25:1, respectively, transforms the glass product into an amorphous glassy state. When the proportion of coal gasification slag in the mixture is further increased to the mass ratio of coal gasification slag to electroplating sludge of 1.5:1, 1.75:1 and 2:1, a variety of crystalline phases reappear in the glass product, mainly silicon-aluminum phases such as SiO2 (PDF#16-0380) and CaAl2Si2O8 (PDF#05-0528) and some metallic phases.

[0076] Under different mixing ratios (coal gasification slag (CGS) and electroplating sludge (ES) mixed at different mass ratios (0.5:1, 0.75:1, 1:1, 1.25:1, 1.5:1, 1.75:1, and 2:1), the metal recovery rates of Cu, Ni, and Fe were as follows: Figure 4 As shown in (b), the metal recovery rate remained at a high level when the mass ratio of coal gasification slag to electroplating sludge was 0.75:1, 1:1, and 1.25:1. Among them, the recovery rates of Cu, Ni, and Fe were the highest when the mass ratio of coal gasification slag to electroplating sludge was 1:1, at 96.33%, 99.56%, and 79.93%, respectively.

[0077] The results above show that the optimized ratio of coal gasification slag to electroplating sludge promotes the amorphous transformation of glass products, enhances the flow characteristics of the melt, and improves the metal recovery rate.

[0078] Meanwhile, the inventors conducted theoretical research on the better effect of mixing coal gasification slag (CGS) and electroplating sludge (ES) at a mass ratio of 1:1.

[0079] XPS was used to characterize the structure of different glass products. The changes in O 1s binding energy of different glass products are as follows: Figure 5 As shown in (a), with the increase of the proportion of electroplating sludge, the O 1s binding energy of the glass products decreased from 531.8 eV when the mass ratio of electroplating sludge to coal gasification slag was 1:2 to 531.1 eV when the mass ratio of electroplating sludge to coal gasification slag was 1:1. However, when the proportion of electroplating sludge was further increased to 1:0.5, the O 1s binding energy gradually increased to 531.3 eV. Subsequently, the high-resolution XPS spectra of O 1s of different glass products were fitted and analyzed. The peak with a binding energy of 532.0 eV was attributed to bridging oxygen bonds (BO), while the peak with a binding energy of 531.0 eV was attributed to non-bridging oxygen bonds (NBO). Figure 5 (b) Quantitative analysis of BO and NBO showed that the relative NBO content in the glass product with a mass ratio of electroplating sludge to coal gasification slag of 1:2 was 39.02%, and the relative NBO content reached its maximum of 62.42% when the proportion of electroplating sludge was increased to 1:1. Figure 5 (c) When the mass ratio of electroplating sludge to coal gasification slag is 1:1, it promotes the conversion of BO to NBO to achieve depolymerization of the melt network. Depolymerization realizes the transformation of the structure from long-range order to disorder, making the glass product amorphous and enhancing the melt flow characteristics.

[0080] Furthermore, the high-resolution Al 2p XPS spectra of different glass products were analyzed. Figure 6 (a) High-resolution XPS spectra of Al 2p in glass products with mass ratios of coal gasification slag to electroplating sludge of 0.5:1, 0.75:1, and 1:1, respectively. The peak at 73.4–74.5 eV belongs to the [AlO4] structural unit, which has a network-forming effect, while the peak at 74.1–75.1 eV belongs to the [AlO6] structural unit, which has a network-modifying effect. It can be seen that as the proportion of electroplating sludge increases, the relative content of [AlO4] increases from 48.72% when the mass ratio of coal gasification slag to electroplating sludge is 1:1 to 58.98% when the mass ratio is 0.5:1. The [AlO4] structural unit is similar to the [SiO4] tetrahedral unit, and the two can combine to form complex Al-O-Si structural groups, resulting in a decrease in the proportion of NBO and weakening the network depolymerization of the glass products. Figure 6 (b) The [AlO4] content of the glass products when the mass ratio of coal gasification slag to electroplating sludge is 0.5:1, 0.75:1 and 1:1, respectively.

[0081] Example 2

[0082] Example 2 investigated the effect of viscosity changes during melting on the glass transition of glass products and the efficiency of metal separation and recovery.

[0083] Coal gasification slag (CGS) and electroplating sludge (ES) were mixed uniformly at a mass ratio of 1:1 to obtain a mixture of coal gasification slag and electroplating sludge. The mixture was placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt it. The melting was maintained at different viscosities (2.9 Pa·s, 3.8 Pa·s, 6.1 Pa·s, 12.8 Pa·s, 21.8 Pa·s) for 90 min. The mixture was then naturally cooled to room temperature and crushed and separated to obtain alloy products and glass products.

[0084] The effect of different melt viscosities (2.9 Pa·s, 3.8 Pa·s, 6.1 Pa·s, 12.8 Pa·s, 21.8 Pa·s) on metal recovery rates (Cu, Ni, Fe) is as follows: Figure 7 As shown in the figure, the recovery rates of Cu, Ni, and Fe are highest when the melt viscosity is 3.8 Pa·s.

[0085] Example 3

[0086] Example 3 investigated the effects of adding different amounts of B2O3 (0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge) to the system on the glass transition of glass products and the efficiency of metal separation and recovery.

[0087] Coal gasification slag (CGS) and electroplating sludge (ES) were mixed evenly at a mass ratio of 1:1. B2O3 was added at mass ratios of 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of the coal gasification slag and electroplating sludge, respectively. The mixture was then mixed evenly to obtain a mixture of coal gasification slag, electroplating sludge, and B2O3. The mixture was placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt it. The melt viscosity was maintained at 3.8 Pa·s, and the melting time was 90 min. The mixture was then allowed to cool naturally to room temperature and crushed and separated to obtain alloy products and glass products.

[0088] Figure 8 (a) shows the crystalline phase changes in glass products under conditions where the added mass of B2O3 was 0%, 2.5%, 5%, 7.5%, and 10% of the total mass of coal gasification slag and electroplating sludge. Specifically, without the addition of B2O3, the glass product exhibited a highly crystalline state; when the added amount of B2O3 was 2.5 wt%, the melt began to transform into an amorphous glassy state; when the added amount exceeded 5 wt%, the glass product essentially completed the transformation into an amorphous glassy state. The enhanced melting characteristics simultaneously promoted metal recovery (…). Figure 8(b) When the B2O3 addition was increased from 0 wt% to 7.5 wt%, the recoveries of Cu, Ni, and Fe significantly increased from 79.21%, 89.01%, and 58.01% to 97.31%, 99.17%, and 81.84%, respectively. However, when the B2O3 addition was further increased to 10 wt%, the recoveries of Cu, Ni, and Fe decreased to 94.97%, 97.72%, and 78.80%, respectively. This phenomenon may be attributed to the increased chemical dissolution loss of Cu, Ni, and Fe in the glass product due to the addition of excessive B2O3.

[0089] The introduction of B2O3 promoted the demelting glass transition of the electroplating sludge and coal gasification slag co-melting system. To elucidate the regulatory mechanism of B2O3 chemical species, FTIR characterization analysis was performed on glass products with different B2O3 addition amounts. Figure 9 (a) FTIR spectra of glass products with different amounts of B2O3 addition. The values ​​in the 600-800 cm⁻¹ range are shown. -1 The frequency band belongs to the bending vibration of [AlO4] or BOB, 800-1200 cm. -1 The frequency band corresponds to the tensile vibration of [SiO4], 1210 cm. -1 The frequency band corresponds to the tensile vibration of [BO4], 1350cm. -1 The frequency band corresponds to the antisymmetric stretching vibration of [BO3]. The FTIR spectrum of the glass product obtained without the addition of B2O3 shows obvious [AlO4] bending vibration bands and [SiO4] stretching vibration bands, indicating the formation of a Si-O bonded network. Simultaneously, due to the presence of a long-range ordered crystalline phase in the glass product, the absorption peak curve is relatively coarse. With the addition of B2O3, the absorption peak curve becomes smoother, reaching a point at 1200 cm⁻¹. -1 -1600 cm -1 A vibrational band related to the BO bond appeared. Specifically, with the increase of B2O3 addition, the [BO3] signal was significantly enhanced, while the signal growth of tetrahedral [BO4] was slower, indicating the formation of [BO3] structural units in the melt. Due to its special triangular structure, [BO3] cannot form a continuous three-dimensional network after connecting with the silicate network structure, which is conducive to the depolymerization of complex silicon-oxygen network structures.

[0090] For 800 to 1200 cm -1 Gaussian fitting was performed on the FTIR band to obtain Q. n The relative content of structural units is used to characterize the change in the degree of polymerization of silicate networks in glass products with different amounts of B2O3 addition. Figure 9 (b)- Figure 9 (f)). A smaller n value indicates a lower degree of polymerization in the silicon-oxygen network structure, which is beneficial for enhancing the melting properties of the melt. Wherein, Q0 (NBO / Si=4), Q 1 (NBO / Si=3), Q 2 (NBO / Si=2), Q 3 (NBO / Si=1) and Q 4 The characteristic frequencies corresponding to the (NBO / Si=0) structural units are 840-890 cm⁻¹. -1 900-950 cm -1 960-1030 cm -1 1050-1100 cm -1 and 1190 cm -1 Q of glass products obtained under different B2O3 addition conditions 0 Q 1 Q 2 Q 3 and Q 4 The relative content is as follows Figure 10 (a) and Table 3 show that, with the increase of B2O3 addition, the number of simple structural units (Q) in the glass product increases. 0 and Q 1 The relative content of Q in glass products showed an increasing trend. Specifically, without the addition of B2O3, the relative content of Q in glass products... 0 and Q 1 The relative content of B2O3 was only 27.83%, but when the amount of B2O3 added increased to 10%, its relative content rose sharply to 51.36%. Correspondingly, Q 4 Structural units exist only in glass products without the addition of B2O3; complex structural units Q 3 The content of decreased. Under conditions without the addition of B2O3, Q 3 The relative percentage content of structural unit cells was as high as 43.27%, but when the B2O3 addition was increased to 10%, its relative percentage content decreased to 24.30%. The deagglomeration of the complex network structure in the glass products enhanced the melting characteristics of the melt; the amorphous phase content in the glass products with 5 wt%, 7.5 wt%, and 10 wt% B2O3 addition was all higher than 98%. Figure 10 b).

[0091] Table 3. Q in glass products with different B2O3 additions 0 Q 1 Q 2 Q 3 and Q 4 Relative content of structural units (%)

[0092]

[0093] The microstructure and elemental distribution of the alloy product (prepared under the conditions of an electroplating sludge to coal gasification slag mass ratio of 1:1, a B2O3 mass percentage of 7.5 wt%, a melt viscosity of 3.8 Pa·s, and a melting time of 90 min) were analyzed using SEM-EDS. Figure 11 As shown in (a), the alloy can be divided into three typical regions: light-colored (1), dark-colored (2), and black (3), with the light-colored region covering the largest area. EDS surface scanning analysis ( Figure 11 (b)- Figure 11 (e) and point analysis results ( Figure 11 (f)- Figure 11 (h) indicates that the light-colored region is a Cu-Ni-Fe phase, while the dark and black regions are both Cu-Ni-Fe-S phases. Specifically, the chemical composition of the light-colored region is Cu 13.28%, Ni 64.16%, and Fe 22.57%, while the dark and black regions both contain S, with contents of 27.08% and 24.56%, respectively. These results confirm that a Cu-Ni-Fe-based metal alloy product is formed through the mutual solubility of Cu, Ni, and Fe.

[0094] Due to the effects of chemical bonds and differences in surface tension, the alloy phase and the nonmetallic phase are almost immiscible in the melt. During the melting process, the alloy particles formed through reduction continuously migrate and aggregate in the melt, and then separate from the melt under the influence of gravity.

[0095] Figure 12 SEM-EDS analysis was performed on the alloy products obtained without B2O3 (the alloy product prepared under the conditions of a 1:1 mass ratio of electroplating sludge to coal gasification slag, no B2O3 added, a melt viscosity of 3.8 Pa·s, and a melting time of 90 min) and with 7.5 wt% B2O3 added (the alloy product prepared under the conditions of a 1:1 mass ratio of electroplating sludge to coal gasification slag, a B2O3 addition mass of 7.5% of the total mass of coal gasification slag and electroplating sludge, a melt viscosity of 3.8 Pa·s, and a melting time of 90 min). Figure 12 (a) SEM-EDS analysis of the alloy product obtained by melting the mixture without the addition of B2O3; Figure 12 (b) SEM-EDS analysis of the alloy product obtained by melting a mixture containing 7.5 wt% B2O3; Figure 13It can be seen that the product without B2O3 has a loose and porous structure, and the alloy phase is irregularly dispersed in the non-metallic phase. However, in the product with 7.5% B2O3 by mass, the alloy phase forms more regular spherical shapes and is effectively separated from the dense non-metallic phase. EDS elemental distribution results show that Cu and Ni are almost completely enriched in the alloy phase; while Fe is mainly distributed in the alloy phase, with a small amount present in the non-metallic phase composed of Ca, Si, and Al.

[0096] Example 4

[0097] Example 4 investigated the effects of different melting times (30 min, 60 min, 90 min, 120 min, and 150 min) on the glass transition of the glass products and the efficiency of metal separation and recovery under the conditions of a mass ratio of electroplating sludge to coal gasification slag of 1:1, a B2O3 addition mass of 7.5% of the total mass of coal gasification slag and electroplating sludge, and a melt viscosity of 3.8 Pa·s.

[0098] Coal gasification slag (CGS) and electroplating sludge (ES) were mixed evenly at a mass ratio of 1:1. 7.5% B2O3 (based on the total mass of coal gasification slag and electroplating sludge) was added and mixed evenly to obtain a mixture of coal gasification slag, electroplating sludge, and B2O3. The mixture was placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt it, maintaining a melt viscosity of 3.8 Pa·s. The melting times were 30 min, 60 min, 90 min, 120 min, and 150 min, respectively. The mixture was then naturally cooled to room temperature and crushed and separated to obtain alloy products and glass products.

[0099] Figure 13 (a) XRD patterns of the glass products after melting for different times (30 min, 60 min, 90 min, 120 min, 150 min). As shown in the figure, the products after melting for different times (30 min, 60 min, 90 min, 120 min, 150 min) all exhibit an amorphous glassy state. The effect of different melting times (30 min, 60 min, 90 min, 120 min, 150 min) on the metal recovery rate (Cu, Ni, Fe) is as follows: Figure 13As shown in (b), the metal recovery efficiency initially increases with time and then tends to stabilize. Under the condition of a melting time of 30 min, the recovery rates of Cu, Ni, and Fe are 86.47%, 85.74%, and 69.20%, respectively. When the melting time is extended to 90 min, the recovery rates of Cu, Ni, and Fe increase to 97.31%, 99.17%, and 81.84%, respectively, and then remain relatively stable. Extending the melting time not only facilitates the metal reduction reaction but also increases the activation energy of metal atoms under high-temperature conditions, thereby promoting the formation of a stable alloy structure. During this process, the metal phase continuously migrates and aggregates, eventually forming an alloy phase that separates from the glass phase. Therefore, extending the melting time is beneficial to improving the metal recovery efficiency.

[0100] In summary, when the mass ratio of electroplating sludge to coal gasification slag is 1:1, and B2O3 is added at a mass of 7.5% of the total mass of coal gasification slag and electroplating sludge, and the system is melted for 90 min at a melt viscosity of 3.8 Pa·s, the system can achieve glass transition with reduced melting point. Simultaneously, the recovery rates of Cu, Ni, and Fe reach 97.31%, 99.17%, and 81.84%, respectively. This successfully constructs a eutectic glass transition synchronous metal recovery system based primarily on electroplating sludge and coal gasification slag.

[0101] The glass products prepared under optimal conditions (a mass ratio of electroplating sludge to coal gasification slag of 1:1, a B2O3 addition mass of 7.5% of the total mass of coal gasification slag and electroplating sludge, a melt viscosity of 3.8 Pa·s, and a melting time of 90 min) were tested as follows:

[0102] Detection 1): Analysis of the chemical speciation of heavy metals in the sample.

[0103] A modified BCR sequential extraction method was used to analyze the chemical speciation of heavy metals in glass product samples. The specific procedure is as follows: 1.0 g of glass product sample was accurately weighed, and four sequential extraction steps were performed. The heavy metal content in the extract and the final residue of each step was determined by ICP-OES. The first step was the extraction of the acid-extractable form of metal (F1): 40 mL of 0.11 mol / L acetic acid solution was added to the sample, and the mixture was shaken at 30 rpm for 18 hours at room temperature. After the reaction, the mixture was centrifuged, and the supernatant was filtered through a 0.45 μm filter membrane. The resulting filtrate was the F1 extract. The remaining residue was washed with 15 mL of deionized water and centrifuged again. The washings were discarded, and the residue was retained. The second step was the extraction of the reducible form of metal (F2): 40 mL of 0.5 mol / L hydroxylamine hydrochloride solution was added to the residue obtained in the previous step, and the mixture was shaken for 18 hours under the same conditions (room temperature, 30 rpm). The same centrifugation, filtration, and washing procedures as in step one were then performed. The F2 extract was collected, and the washed residue was retained. The third step was the extraction of the metal-oxidizable state (F3): First, 10 mL of 30% hydrogen peroxide solution was added to the residue from the previous step, and the mixture was allowed to stand at room temperature for 1 hour. Then, the mixture was heated in an 85°C water bath until the volume decreased to 2-3 mL. After cooling, another 10 mL of 30% hydrogen peroxide was added, and the heating and evaporation process was repeated. Finally, 40 mL of 1.0 mol / L ammonium acetate solution was added to the cooled residue, and the mixture was shaken at 30 rpm on a rotary shaker for 18 hours at room temperature. Similarly, after centrifugation, filtration, and washing, the F3 extract was collected, and the final residue was retained. The fourth step was the determination of the metal residue state (F4): The residual solid obtained in step three was dried at 105°C for 12 hours, and then digested. After digestion, the residual heavy metal content was determined using ICP-OES.

[0104] Furthermore, the Risk Assessment Code (RAC) and the Potential Ecological Risk Index (RI) were used to assess the individual ecological risks of heavy metals in the samples and the overall potential ecological risks of heavy metals, respectively. The RAC value was calculated as shown in Equation 2:

[0105]

[0106] in, C F1 It represents the acid-extractable content (mg / kg) of a single metal Cu, Ni, Fe, Zn, Pb, and Cr in the sample. C Total It is the total content of the metal in the sample (mg / kg).

[0107] RI represents the overall potential ecological risk of heavy metals in the sample, and its calculation is shown in Equation 3:

[0108]

[0109] in, A i This represents the proportion of the active forms (F1 + F2 + F3) of the metals Cu, Ni, Fe, Zn, Pb, and Cr in the sample. D i The proportion of its residual state (F4) in the sample. T i The values ​​for the metals are 5, 5, 2, 5, and 1 for Cu, Ni, Cr, Pb, and Zn, respectively. The evaluation criteria for RAC and RI are shown in Table 4.

[0110] Table 4 Evaluation Criteria for RAC and RI

[0111]

[0112] In this application, most of the metals in the eutectic system of electroplating sludge and coal gasification slag are recovered through alloying, while the remaining heavy metals are solidified in the glass product. The distribution of heavy metal speciation in the original sample (a mixed sample with an electroplating sludge to coal gasification slag mass ratio of 1:1, B2O3 addition mass of 7.5% of the total mass of coal gasification slag and electroplating sludge) and the glass product (glass product prepared under optimal conditions (electroplating sludge to coal gasification slag mass ratio of 1:1, B2O3 addition mass of 7.5% of the total mass of coal gasification slag and electroplating sludge, melt viscosity of 3.8 Pa·s, and melting time of 90 min)) was analyzed using the improved BCR continuous extraction experiment described above to evaluate the solidification and stabilization effect of heavy metals in the glass product. The speciation of heavy metals in the original sample and the glass product is shown below. Figure 14 As shown, Figure 14 (a) shows the speciation of heavy metals in the original sample. Figure 14 (b) The distribution of heavy metal speciation in the obtained glass products shows that, compared with the original mixed sample before melting, most heavy metal elements in the glass products exist in stable forms. In the original sample, the proportions of unstable forms (F1+F2) of Cu, Ni, and Zn reached 87.6%, 50.7%, and 82.6%, respectively, indicating poor stability of heavy metals. In the glass products, the proportions of unstable forms (F1+F2) of Cu, Ni, Fe, Cr, and Zn decreased to 2%, 9.2%, 5.3%, 6.3%, and 0.7%, respectively, with most heavy metals stably solidified in the glass matrix. Furthermore, based on the proportions of each chemical form of heavy metal in the original sample and glass slag, their RAC and RI values ​​were calculated (Table 5).

[0113] Table 5. RAC and RI values ​​of the original sample and the glass product

[0114]

[0115] In the original sample, the RAC values ​​of Cu, Ni, and Zn were 67.84%, 35.75%, and 63.98%, respectively, all within the extremely high-risk range, while the RAC value of Cr was within the medium-risk range. In contrast, the RAC values ​​of heavy metals in the glass product were all below 10%, which can be considered low-risk or no-risk. Due to the high proportion of acid-soluble (F1), reducible (F2), and oxidizable (F3) forms of heavy metals, the RI value of the original sample was as high as 168.18; while the glass product showed good curing and stabilization effects on heavy metals, with an RI value of only 19.10, indicating a low overall potential risk from heavy metals. Therefore, the remaining heavy metals were effectively cured and stabilized in the glass product.

[0116] Test 2): Leaching toxicity analysis of glass products

[0117] According to the "Solid Waste Leaching Toxicity Method - Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007), a heavy metal leaching toxicity test was carried out on the molten glass product, and the measured heavy metal content of the leaching solution was compared with the standard limit in the "Technical Requirements for Vitrified Solid Waste Products" (GB / T 41015-2021). The experimental steps are as follows: (1) Prepare the leaching solution: mix sulfuric acid and nitric acid at a mass ratio of 2:1, then dilute with deionized water and adjust the pH to 3.20±0.05; (2) Leach the glass product with a liquid-solid ratio of 10:1, maintain the temperature at 23±2 °C, oscillate at a frequency of 30±2 rpm / min, and oscillate for 18±2 h; (3) After the reaction, put the solid-liquid mixture into a centrifuge and centrifuge at 4000 rpm for 5 min, collect the supernatant and seal it for storage, and use it for heavy metal content determination.

[0118] To verify the harmlessness effect of the glass products, a leaching toxicity test was conducted, and the results are shown in Table 6.

[0119] Table 6 Leaching toxicity of glass products (mg / L)

[0120]

[0121] Test results showed that no heavy metals Cu and Zn were detected in the glass product sample. The toxicity leaching values ​​of Ni and Cr were 0.007 mg / L and 0.005 mg / L, respectively, both far below the limits specified in the "Technical Requirements for Vitrification Products of Solid Waste" (GB / T41015-2021). Therefore, the glass product meets the requirements for harmless treatment and is feasible for resource utilization.

[0122] Example 5

[0123] Different timing of B2O3 addition was studied.

[0124] Experimental Group 1: Coal gasification slag (CGS) and electroplating sludge (ES) were mixed evenly at a mass ratio of 1:1. 7.5% of B2O3 (based on the total mass of coal gasification slag and electroplating sludge) was added and mixed evenly to obtain a mixture of coal gasification slag, electroplating sludge, and B2O3. The mixture was placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt it. The melt viscosity was maintained at 3.8 Pa·s, and the melting time was 90 min. The mixture was then naturally cooled to room temperature and crushed and separated to obtain alloy products and glass products.

[0125] Experimental Group 2: Coal gasification slag (CGS) and electroplating sludge (ES) were mixed evenly at a mass ratio of 1:1 to obtain a mixture of coal gasification slag and electroplating sludge. The mixture was placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt it. The melt viscosity was maintained at 3.8 Pa·s for 20 min. Then, 7.5% of the total mass of coal gasification slag and electroplating sludge B2O3 was added to the system and mixed evenly. The melt viscosity was maintained at 3.8 Pa·s for 70 min. The mixture was then allowed to cool naturally to room temperature and crushed and separated to obtain alloy products and glass products.

[0126] Experimental Group 3: Coal gasification slag (CGS) and electroplating sludge (ES) were mixed evenly at a mass ratio of 1:1. 3.5% B2O3 (based on the total mass of coal gasification slag and electroplating sludge) was added and mixed evenly to obtain a mixture of coal gasification slag, electroplating sludge, and B2O3. The mixture was placed in an arc-shaped corundum crucible and heated under a nitrogen atmosphere to melt it. The melt viscosity was maintained at 3.8 Pa·s, and the melting time was 20 min. Then, 4% B2O3 (based on the total mass of coal gasification slag and electroplating sludge) was added to the system and mixed evenly. The melt viscosity was maintained at 3.8 Pa·s, and the melting time was 70 min. The mixture was naturally cooled to room temperature and then crushed and separated to obtain alloy products and glass products.

[0127] Application Example 1

[0128] Microcrystalline glass was prepared by heat treatment using the glass product obtained in Experimental Group 1 of Example 5. The heat treatment conditions were set to 750 °C for 2 h and 850 °C for 2 h.

[0129] The DSC test results of the glass product obtained in Experimental Group 1 of Example 5 are as follows: Figure 15 As shown in (a), the DSC curves show an endothermic peak at 642.53 °C and a distinct exothermic peak at 744.44 °C, which correspond to the glass transition temperatures (T0, T0) of the glass products, respectively.g ) and crystallization temperature (T) c ).

[0130] XRD patterns of glass-ceramic samples prepared under different heat treatment conditions (750 °C, 2 h and 850 °C, 2 h) are shown below. Figure 15 As shown in (b). XRD analysis revealed significant crystalline phase precipitation in the glass product after heat treatment at 750 °C for 2 h. When the heat treatment temperature was increased to 850 °C, the number and intensity of diffraction peaks of the crystalline phases in the glass product increased significantly, and its crystallinity reached 69.92%. The precipitated crystalline phases were SiO2, CaAl2Si2O8, CaSiO3, and Ca2SiO4. Simultaneously, SEM images clearly showed the distribution of the crystalline phases in the glass-ceramic matrix. Figure 15 (c)).

[0131] Application Example 2

[0132] The glass products obtained from experimental groups 1, 2, and 3 in Example 5 were heat-treated to prepare microcrystalline glass. The heat treatment conditions were 750 °C for 2 hours.

[0133] The obtained microcrystalline glass underwent performance testing. Vickers hardness testing was conducted according to the "Test Method for Room Temperature Hardness of Fine Ceramics" (GB / T 16534-2009), using an MH-6 Vickers hardness tester. The microcrystalline glass was held under a load of 196 N for 10 s, and the corresponding Vickers hardness was measured. Acid and alkali corrosion resistance testing was conducted according to the "Test Method for Acid and Alkali Corrosion Resistance of Fine Ceramics" (JC / T 2138-2012), using 3 mol / L H₂SO₄ solution and 6 mol / L NaOH solution to test the corrosion resistance of the samples. Water absorption was determined according to the "Test Methods for Ceramic Tiles Part 3: Determination of Water Absorption, Apparent Porosity, Apparent Relative Density and Bulk Density" (GB / T 3810.3-2016). The test results are shown in Table 7 below.

[0134] Table 7. Effects of different addition times of B2O3 on the quality of glass-ceramics.

[0135]

[0136] The experimental results show that optimizing the timing of B2O3 addition can improve the Vickers hardness, water absorption, acid corrosion resistance and alkali corrosion resistance of glass-ceramics.

[0137] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for co-melting glassification of electroplating sludge and coal gasification slag and efficient recovery of metal alloy, characterized in that, include: The dried coal gasification slag is mixed evenly with electroplating sludge, melted, cooled, and separated to obtain glass products and alloys. The mass ratio of coal gasification slag to electroplating sludge is 0.75-1.25:1; the melting time is 30-150 min. The viscosity of the molten system was controlled to be 2.9-21.8 Pa·s; Based on the mass of the coal gasification slag as 100%, the coal gasification slag includes 17-20 wt% CaO, 41-44 wt% SiO2, 16-19 wt% Al2O3, 2-4 wt% Na2O, 12-15 wt% Fe2O3, and 6-7.5 wt% C; Based on the mass of the electroplating sludge as 100%, the electroplating sludge includes 33-36 wt% CaO, 1.5-4 wt% SiO2, 1.5-4 wt% Al2O3, 1.5-4 wt% Na2O, 4-7 wt% Fe2O3, and 3-5 wt% C; B2O3 is also added to the system composed of electroplating sludge and coal gasification slag. The mass of B2O3 added is 2.5-10% of the total mass of coal gasification slag and electroplating sludge.

2. The method for co-melting and vitrifying electroplating sludge and coal gasification slag and efficiently recovering metal alloys according to claim 1, characterized in that, The viscosity of the molten system was controlled to be 2.9-6.1 Pa·s.

3. The method for co-melting and vitrifying electroplating sludge and coal gasification slag and efficiently recovering metal alloys according to claim 1, characterized in that, The melting time is 80-95 minutes.

4. The method for co-melting and vitrifying electroplating sludge and coal gasification slag and efficiently recovering metal alloys according to claim 1, characterized in that, Add 2.5-4.5% B2O3 of the total mass of coal gasification slag and electroplating sludge before melting, and add another 2.5-4.5% B2O3 of the total mass of coal gasification slag and electroplating sludge 20 minutes after melting.

5. A microcrystalline glass, characterized in that, The microcrystalline glass is obtained by heat treatment of the glass product prepared by the method according to any one of claims 1-4.

6. The microcrystalline glass according to claim 5, characterized in that, The heat treatment temperature is 750°C and the time is 1.5-2.5h.

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