Method for preparing ceramic frit from electronic waste

Abstract

The invention discloses a method for preparing a ceramic frit from electronic waste. The ceramic frit is prepared from the following raw materials in parts by mass: 40-55 parts of waste electronic glass, 15-27 parts of polishing powder, 8-10 parts of waste aluminum oxide, 6-8 parts of waste desulfurized gypsum, 3-6 parts of a boron-containing modifier, 5-8 parts of waste fuel and 1-3 parts of a mineralizing agent. The method comprises the following steps: stirring and mixing waste electronic glass, polishing powder, waste aluminum oxide, waste desulfurized gypsum, a boron-containing modifier and a mineralizer, adding waste fuel, further stirring and mixing, and then feeding into a granulator for granulation; feeding the prepared particles into a smelting furnace for calcining, wherein the calcining temperature is 1050-1150 DEG C; and carrying out water quenching molding on the molten material to obtain the ceramic frit. The method for preparing the ceramic frit from the electronic waste solves the technical problems of high energy consumption of ceramic frit calcination and resource waste caused by direct treatment of the electronic waste in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of ceramic frit preparation technology, specifically relating to a method for preparing ceramic frit using electronic waste. Background Technology

[0002] The electronics manufacturing industry generates a large amount of solid and hazardous waste annually, including polishing powder, waste electronic glass, waste alumina, waste lubricating oil, and waste adhesives. Waste polishing powder contains rare earth oxides such as CeO2 and La2O3, as well as metallic lithium, aluminum, and silicon oxides, along with impurities such as flocculants, making its resource utilization difficult. Currently, it is mainly disposed of through co-processing in cement kilns. Waste electronic glass primarily consists of SiO2 and Al2O3, and also contains sodium and potassium alkali metal oxides and paint. Due to its high sodium and potassium content and paint content, it cannot be remelted for curtain wall glass production. Landfilling is the primary method of disposal, posing risks such as land occupation and metal leakage. Waste alumina mainly comes from air compressor replacement waste. Waste lubricating oil and waste adhesives are mainly treated by incineration, requiring the payment of high disposal fees.

[0003] Existing ceramic frit preparation technologies suffer from high energy consumption during calcination. Traditional processes require calcination temperatures of 1450-1500℃, resulting in high energy costs. Current technologies only reduce energy consumption through conventional process adjustments, leading to limited energy savings and failing to overcome the high energy consumption bottleneck. Some existing technologies use electronic waste as a raw material for ceramic frits, such as the ceramic frit and glaze defect-free ceramic frit and its production method disclosed in Chinese Invention Patent Application No. 2024106996289, which uses waste glass as a single solid waste raw material and still suffers from high calcination energy consumption. While SiO2 in electronic waste can serve as a core framework component for glazes, and electronic waste contains alkali metal oxides and rare earth metal oxides such as CeO2 and La2O3, the inherent fluxing properties of alkali metal oxides and the strengthening effect of rare earth metals on ceramic crystal phases mean that directly disposing of electronic waste would result in resource waste. Summary of the Invention

[0004] In view of the existing technical problems, the present invention aims to provide a method for preparing ceramic frit using electronic waste. This method can solve the technical problems of high energy consumption in calcination of ceramic frit and resource waste caused by direct disposal of electronic waste in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing ceramic frit using electronic waste comprises the following raw materials in parts by weight: 40-55 parts waste electronic glass, 15-27 parts polishing powder, 8-10 parts waste alumina, 6-8 parts waste desulfurized gypsum, 3-6 parts boron-containing modifier, 5-8 parts waste fuel, and 1-3 parts mineralizer. The waste electronic glass, polishing powder, waste alumina, waste desulfurized gypsum, boron-containing modifier, and mineralizer are mixed by stirring, and then waste fuel is added and further mixed. The mixture is then fed into a granulator for granulation. The resulting granules are calcined in a furnace at a temperature of 1050-1150℃. The molten material is then water-quenched to form ceramic frit.

[0007] All raw materials are dry-based. SiO2 from waste electronic glass serves as the core framework component of the glaze, providing excellent stability, hardness, and chemical durability, thus forming the basis for a high-quality glaze layer. K2O and Na2O from waste electronic glass act as "network modifiers" during the ceramic frit preparation process, providing oxygen ions (O2O2). 2- Sodium ions can break silicon-oxygen bonds (Si-O-Si), depolymerizing the rigid three-dimensional network into smaller units, thereby drastically reducing high-temperature viscosity. This is the main force driving down the melting temperature. + With a small radius and high electric field strength, its viscosity-reducing effect is very significant at high temperatures (>1300°C); potassium ions (K... + With a larger radius and lower electric field strength, it can better reduce low-temperature viscosity, improve the thermal expansion properties of glass, and prevent crystallization (devitrification); the ratio of K2O and Na2O can optimize melting performance and final product performance across the entire temperature range. Lanthanum (La) in polishing powder... 3+ Lanthanum ions (La) are expensive "network intermediates". 3+ High charge, large radius, and electric field strength between those of network-formed materials (such as Si). 4+ ) and network modifiers (such as Na) + Between them, it can partially participate in the network, acting as a "bridge". 3+ The addition of cerium can compensate for the decrease in chemical stability caused by the introduction of a large amount of alkali metals. It can improve the hardness, refractive index and weathering resistance of glass. During the melting process, it can stabilize the melt structure, prevent phase separation and make the glass melt more homogeneous. CeO2 in polishing powder can be used as an effective antibacterial component. CeO2 has a cubic fluorite structure, in which cerium and oxygen occupy the tetrahedral and octahedral interstices, respectively. Due to the large number of defects in CeO2, CeO2(Ⅳ) will be transformed into CeO2(Ⅲ) in order to stabilize the defects. The reversible conversion between CeO2(Ⅳ) and CeO2(Ⅲ) will generate reactive oxygen species, which will inactivate bacteria through oxidative stress. In addition, cerium (CeO2(Ⅳ)) can also be used to treat bacteria. 3+ / Ce 4+CeO2 can be used as a flexible "oxidizing-reducing agent" and "clarifying agent". CeO2 acts as an oxidizing agent (Ce... 4+ At high temperatures, it decomposes and releases oxygen (4CeO2 → 2Ce2O3 + O2↑), promoting the clarification of the glass melt and removing tiny bubbles; CeO2 acts as a reducing agent (Ce... 3+ Ce can exist stably, and its variable valence properties can regulate the redox balance in the melt, affecting the valence state of other multivalent elements (such as iron), thereby improving the glass color. 3+ It can also be used as a network modifier to further reduce viscosity. The clarifying effect of cerium complements the viscosity-reducing effect of alkali metals—lower viscosity facilitates bubble escape, while the oxygen provided by cerium expands and promotes bubble expulsion. K₂O and Na₂O, as important fluxes, significantly reduce the melting temperature of the glaze, decrease energy consumption during firing, and have a mild fluxing effect, resulting in more uniform glaze melting and a smooth, even glaze surface. Combined with the synergistic effect of lanthanum and cerium, they improve the uniformity of the melt melt and increase the hardness of the melt. Waste desulfurized gypsum can adjust the melt viscosity during calcination and improve mechanical strength. CaO can adjust the crystal phase (forming an anorthite phase, improving acid resistance), while SO₄... 2- It can suppress the volatilization of rare earth elements. Boron-containing modifiers can reduce the viscosity of the glass phase and improve the fluidity of the molten metal. Adding waste fuel to the raw materials can reduce fuel costs during calcination, and mineralizers can refine grains and improve thermal stability.

[0008] Preferably, the waste electronic glass contains 55-60% SiO2, 15-20% Al2O3, 15% K2O, and 5% Na2O by mass; the polishing powder contains 15-40% CeO2 and 10-20% La2O3 by mass. The waste electronic glass also contains small amounts of MgO, CaO, and P2O5. MgO and CaO not only adjust the melt viscosity, improve mechanical strength, and help lower the melting temperature, but also improve the gloss and transparency of the glaze, enhancing the texture of the glaze layer. Furthermore, P2O5 can act as an opacifier and flux, adjusting the opacity of the glaze to meet different decorative needs. The polishing powder also contains small amounts of lithium, aluminum, and silicon oxides.

[0009] Preferably, the mass fraction of alumina in the waste alumina is not less than 85%. Waste alumina in electronic waste also contains a small amount of Na2O and Al2O3, which can effectively increase the melting temperature range of the glaze, preventing glaze flow during firing, and simultaneously enhancing the bonding strength between the glaze layer and the body, reducing the risk of glaze peeling. Na2O lowers the melting temperature of the glaze, reducing energy consumption during firing, and its fluxing effect is gentle, allowing the glaze to melt more evenly and contributing to the formation of a smooth and flat glaze surface.

[0010] Preferably, the mass fraction of CaSO4·2H2O in the waste desulfurization gypsum is not less than 90%.

[0011] Preferably, the mass fraction of B2O3 in the boron-containing modifier is not less than 42%.

[0012] Preferably, the waste fuel is one or a combination of two of waste mineral oil and waste organic solvent, with a calorific value of 3000-5000 kcal / kg; the mineralizing agent is one or a combination of two of aluminum phosphate and magnesium pyrophosphate.

[0013] Preferably, before mixing the raw materials, the polishing powder and desulfurized gypsum are dried at 300–400°C until the moisture content is less than 20%, and the waste electronic glass and waste alumina are ground to a particle size of no more than 40 μm. Grinding the waste electronic glass and waste alumina to a particle size of no more than 40 μm can improve the melting rate. When the particle size of the waste electronic glass and waste alumina exceeds 40 μm, the melting rate decreases to 85%.

[0014] Preferably, the waste gas generated during furnace calcination is used to dry polishing powder and waste desulfurized gypsum. The acidic pollutants in the waste gas are treated by a limestone-gypsum desulfurization tower to generate calcium sulfate, which is then returned as raw material. The dust in the waste gas is treated by a bag filter.

[0015] Preferably, the particles are fed into a granulator to produce irregular particles of 20-50mm. Particles smaller than 20mm are prone to dust generation, while particles larger than 50mm are not thoroughly calcined.

[0016] Preferably, the furnace chamber pressure is -50 to 0 Pa, and the calcination time is 30 to 40 minutes. The slightly negative furnace chamber pressure can prevent flue gas from escaping.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The present invention adopts a method for preparing ceramic frits from electronic waste, taking into account the complementarity of electronic solid waste components, and fully utilizes the multi-source solid waste of electronic enterprises, avoiding secondary pollution and resource waste caused by batch disposal of solid waste.

[0019] 2. The present invention employs a method for preparing ceramic frits from electronic waste, which fully utilizes the alkali metal oxides in waste electronic glass to lower the melting point and the synergistic strengthening effect of rare earth metals in polishing powder. At the same time, waste fuel is added to lower the calcination temperature of the ceramic frit, resulting in a significant reduction in energy consumption.

[0020] 3. The present invention employs a method for preparing ceramic frits from electronic waste, utilizing the strengthening effect of rare earth metals in the polishing powder to enhance the microhardness and thermal stability of the frits, and improve their wear resistance and corrosion resistance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process flow for the method of preparing ceramic frit using electronic waste according to the present invention. Detailed Implementation

[0022] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. Unless otherwise specified, all percentages below refer to mass percentages.

[0023] Example 1

[0024] The raw material ratio (parts by weight) used in this embodiment is as follows: 45 parts waste electronic glass, 20 parts polishing powder (CeO2 30%, La2O3 15%), 10 parts waste alumina, 8 parts desulfurized gypsum, 4 parts boron-containing modifier, 2 parts mineralizer, and 6 parts waste fuel. All raw materials are on a dry basis. The waste fuel consists of waste mineral oil and waste ethanol, with a mass ratio of 1:1 and a calorific value of 4200 kcal / kg. The boron-containing modifier is boron tailings powder, and the mineralizer is aluminophosphate.

[0025] This embodiment uses a method for preparing ceramic frits from electronic waste, and the process flow is as follows: Figure 1 As shown, the specific steps include:

[0026] Step S1, Pretreatment: Dry the polishing powder and desulfurized gypsum at a drying temperature of 130℃ to a moisture content of 20%, and grind the waste electronic glass and waste alumina for 1.5 hours to obtain a particle size of 35μm;

[0027] Step S2, Mixing and Granulation: Add the pretreated polishing powder, desulfurized gypsum, waste electronic glass, waste alumina, boron-containing modifier and mineralizer into the mixer, mix at 300 r / min for 15 min, then add waste fuel and mix for 5 min to ensure uniform coating of fuel; send to the granulator, granulate diameter 35 mm, compressive strength 1.5 MPa;

[0028] Step S3, calcination and melting: The granules obtained in step S2 are fed into the glass melting furnace through a screw feeder (speed 10 r / min), the furnace pressure is -10 Pa (slight negative pressure to prevent flue gas from overflowing); calcination temperature: 1100℃, calcination time 35 min, excess air coefficient 1.2 to ensure complete combustion;

[0029] Exhaust gas treatment: The glass melting furnace generates exhaust gas at a temperature of approximately 300~400℃. After drying polishing powder and components with high moisture content in desulfurized gypsum, the temperature is reduced to 130~160℃. The flue gas contains acidic pollutants such as SO2. It is treated by a limestone-gypsum desulfurization tower (liquid-to-gas ratio 8L / m³), and the SO2 emission is ≤35mg / m³ (GB 25464-2010). The dust is treated by a bag filter (efficiency ≥99.9%), and the generated calcium sulfate is returned to the raw material pretreatment process section.

[0030] Step S4, water quenching and forming: The molten material (temperature 1100℃) obtained in step S3 is introduced into a room temperature water tank through a chute. The water temperature is 25℃ and the cooling rate is 60℃ / s. After cooling, a ceramic frit is obtained.

[0031] Example 2

[0032] The raw material ratio (parts by weight) used in this embodiment is as follows: 40 parts waste electronic glass, 27 parts polishing powder (CeO2 30%, La2O3 15%), 10 parts waste alumina, 8 parts desulfurized gypsum, 6 parts boron-containing modifier, 3 parts mineralizer, and 6 parts waste fuel with a calorific value of 4200 kcal / kg. All raw materials are on a dry basis. The boron-containing modifier is boron tailings powder, and the mineralizer is magnesium pyrophosphate.

[0033] This embodiment uses a method for preparing ceramic frits from electronic waste, and the process flow is as follows: Figure 1 As shown, the specific steps include:

[0034] Step S1, Pretreatment: Dry the polishing powder and desulfurized gypsum at a drying temperature of 130℃ to a moisture content of 20%, and grind the waste electronic glass and waste alumina for 2 hours to obtain a particle size of 30μm;

[0035] Step S2, Mixing and Granulation: Add the pretreated polishing powder, desulfurized gypsum, waste electronic glass, waste alumina, boron-containing modifier and mineralizer into the mixer, mix at 300 r / min for 15 min, then add waste fuel and mix for 5 min to ensure uniform coating of fuel; send to the granulator, granulate diameter 50 mm, compressive strength 1.4 MPa;

[0036] Step S3, Calcination and Melting: The granules obtained in step S2 are fed into the glass melting furnace through a screw feeder (speed 10 r / min). The furnace pressure is -10 Pa (slight negative pressure to prevent flue gas from overflowing); calcination temperature: 1120℃, calcination time: 30 min, excess air coefficient: 1.2 to ensure complete combustion;

[0037] Exhaust gas treatment: The glass melting furnace generates exhaust gas at a temperature of approximately 300~400℃. After drying polishing powder and components with high moisture content in desulfurized gypsum, the temperature is reduced to 130~160℃. The flue gas contains acidic pollutants such as SO2. It is treated by a limestone-gypsum desulfurization tower (liquid-to-gas ratio 8L / m³), and the SO2 emission is ≤35mg / m³ (GB 25464-2010). The dust is treated by a bag filter (efficiency ≥99.9%), and the generated calcium sulfate is returned to the raw material pretreatment process section.

[0038] Step S4, water quenching and forming: The molten material (temperature 1120℃) obtained in step S3 is introduced into a room temperature water tank through a chute. The water temperature is 30℃ and the cooling rate is 55℃ / s. After cooling, ceramic frit is obtained.

[0039] Comparative Example 1

[0040] The raw material ratio (parts by mass) used in this comparative example is as follows: 60 parts waste electronic glass, 15 parts waste alumina, 20 parts desulfurized gypsum, 5 parts boron-containing modifier, and 8 parts waste fuel. The boron-containing modifier used is boron tailings powder.

[0041] The difference between the preparation method of this comparative example and that of Example 1 is that the calcination temperature is 1300℃.

[0042] Comparative Example 2

[0043] This comparative example uses the traditional process and raw material ratio (parts by weight): 50 parts quartz sand, 25 parts feldspar, 10 parts alumina, 10 parts calcium carbonate, and 5 parts boric acid, using natural gas as fuel.

[0044] The difference between the preparation method of this comparative example and that of Example 1 is that the calcination temperature is 1350℃.

[0045] Comparative Example 3

[0046] The raw material ratio (parts by weight) used in this comparative example is: 50 parts quartz sand, 25 parts polishing powder, 10 parts alumina, 10 parts calcium carbonate, and 5 parts boric acid. Natural gas is used as fuel.

[0047] The difference between the preparation method of this comparative example and that of Example 1 is that the calcination temperature is 1450℃.

[0048] Comparative Example 4

[0049] The raw material ratio (parts by mass) used in this comparative example is: 75 parts quartz sand, 10 parts alumina, 10 parts calcium carbonate, and 5 parts boric acid. Natural gas is used as fuel.

[0050] The difference between the preparation method of this comparative example and that of Example 1 is that the calcination temperature is 1750℃.

[0051] Comparative Example 5

[0052] The raw material ratio (parts by weight) used in this comparative example is as follows: 64 parts waste electronic glass, 5 parts polishing powder (CeO2 30%, La2O3 15%), 10 parts waste alumina, 15 parts desulfurized gypsum, 4 parts boron-containing modifier, 2 parts mineralizer, and 6 parts waste fuel. The waste fuel consists of waste mineral oil and waste ethanol, with a mass ratio of waste mineral oil to waste ethanol of 1:1 and a calorific value of 4200 kcal / kg. The boron-containing modifier is boron tailings powder, and the mineralizer is aluminophosphate.

[0053] The difference between the preparation method of this comparative example and that of Example 1 is that the calcination temperature is 1300℃.

[0054]

[0055] The frit properties of the examples and comparative examples were tested, and the results are shown in the table below:

[0056] As shown in the table above, Examples 1 and 2 used low melting temperatures (1050–1150°C), resulting in high frit hardness (not less than 7.5 GPa), smooth surfaces, and high antibacterial rates. Comparative Examples 1–5 used melting temperatures not less than 1300°C. Comparative Examples 1 and 2 used raw materials containing only alkali metals and no rare earth metals. Comparative Example 5 contained both alkali and rare earth metals, but the rare earth metal content was lower than in the examples. The resulting frits all had hardness less than 7.5 GPa and exhibited surface irregularities. Comparative Example 3 used raw materials containing rare earth metals but no alkali metals. Comparative Example 4 used raw materials containing neither alkali nor rare earth metals, and both used relatively high melting temperatures.

[0057] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A method for preparing ceramic frit using electronic waste, characterized in that: The following raw materials are used in parts by weight: 40-55 parts waste electronic glass, 15-27 parts polishing powder, 8-10 parts waste alumina, 6-8 parts waste desulfurized gypsum, 3-6 parts boron-containing modifier, 5-8 parts waste fuel, and 1-3 parts mineralizer. The waste electronic glass, polishing powder, waste alumina, waste desulfurized gypsum, boron-containing modifier, and mineralizer are mixed together, and then waste fuel is added and mixed further. The mixture is then fed into a granulator for granulation. The resulting granules are then calcined in a furnace at a temperature of 1050-1150℃. The molten material is then water-quenched to form ceramic frit.

2. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The waste electronic glass contains 55-60% SiO2, 15-20% Al2O3, more than 12% K2O, and more than 4% Na2O by mass; the polishing powder contains 15-40% CeO2 and 10-20% La2O3 by mass.

3. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The mass fraction of alumina in waste alumina shall not be less than 85%.

4. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The mass fraction of CaSO4·2H2O in the waste desulfurization gypsum is not less than 90%.

5. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The mass fraction of B2O3 in the boron-containing modifier is not less than 42%.

6. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The waste fuel is one or a combination of two of waste mineral oil and waste organic solvents, with a calorific value of 3000-5000 kcal / kg; the mineralizing agent is one or a combination of two of aluminum phosphate and magnesium pyrophosphate.

7. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: Before mixing the raw materials, the polishing powder and desulfurized gypsum are dried at 300-400℃ until the moisture content is less than 20%, and the waste electronic glass and waste alumina are ground to a particle size of no more than 40μm.

8. The method for preparing ceramic frit using electronic waste according to claim 7, characterized in that: The waste gas generated during furnace calcination is used to dry polishing powder and waste desulfurized gypsum. The acidic pollutants in the waste gas are treated by limestone-gypsum desulfurization tower to generate calcium sulfate, which is then returned as raw material. The dust in the waste gas is treated by bag filter dust collector.

9. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The pellets are fed into a granulator to produce irregular particles of 20-50mm.

10. The method for preparing ceramic frit using electronic waste according to claim 1, characterized in that: The furnace chamber pressure is -50 to 0 Pa, and the calcination time is 30 to 40 minutes.

Images