A composite tailings-based glass-ceramic and a method for producing the same

Abstract

The application discloses a kind of based on composite tailings' glass-ceramics, including the following weight parts of raw materials: granite tailings 36.9~40.5 parts, lead-zinc tailings 18.4~22.5 parts, quartz sand 15.3~20.2 parts, calcium oxide 9.6~12.9 parts, magnesium oxide 7.8~8.5 parts, titanium dioxide 0~4.3 parts.The application also discloses a kind of based on composite tailings' glass-ceramics preparation method, including the following steps: weighing raw materials ball milling, drying and sieving;Tabletting;Ladder type heating to 1450~1480 ℃ and keeping temperature;Pour into mould, annealing at 590~610 ℃;680~730 ℃ nucleation, 1050~1100 ℃ crystallization.The application helps to reduce the phenomenon of large amount of tailings resource stockpiling, effectively improves the comprehensive utilization rate of tailings resource, reduces the risk of heavy metal leaching, and is suitable for application in building materials.

Description

Technical Field

[0001] This invention relates to the field of glass ceramics, specifically to a microcrystalline glass based on composite tailings and its preparation method. Background Technology

[0002] Microcrystalline glass refers to a base glass with a specific composition that undergoes crystallization heat treatment at a certain temperature regime, resulting in the uniform precipitation of a large number of tiny crystals within the glass, forming a dense material where microcrystalline and glassy phases coexist. Currently, the raw materials for producing microcrystalline glass, apart from quartz sand, are primarily chemical raw materials, leading to high production costs. Furthermore, the glass melting temperature is very high, generally above 1500–1550℃, and the holding time at this melting temperature is relatively long, often requiring 2–4 hours. This high-temperature melting process not only generates significant energy consumption but also exacerbates the erosion of the furnace refractory materials by the molten glass.

[0003] Currently, the stockpiling and discharge of tailings pose hidden, cumulative, and irreversible harms to the ecological environment. Lead-zinc tailings have a complex composition, and the leaching of harmful elements such as Zn, Mn, and Pb during their resource utilization increases the safety risks of tailings resources and significantly limits their application in building materials. Heavy metals in building materials can enter the human body through the respiratory tract and skin, accumulating in the lungs or organs, potentially causing headaches, dizziness, insomnia, forgetfulness, mental confusion, joint pain, kidney stones, and cancer. Lead, in particular, is difficult to eliminate once it enters the body. It directly damages brain cells, especially the neural plate of fetuses, potentially causing congenital shallow cerebral sulci and intellectual disability; in the elderly, it can cause dementia and brain death. Furthermore, the current production of microcrystalline glass is energy-intensive, which is not conducive to energy conservation and environmental protection. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a microcrystalline glass based on composite tailings with a dense structure and low heavy metal content. Another purpose of this invention is to provide a method for preparing microcrystalline glass based on composite tailings with reduced production costs.

[0005] Technical solution: The microcrystalline glass based on composite tailings of the present invention comprises the following raw materials in parts by weight: 36.9-40.5 parts granite tailings, 18.4-22.5 parts lead-zinc tailings, 15.3-20.2 parts quartz sand, 9.6-12.9 parts calcium oxide, 7.8-8.5 parts magnesium oxide, and 0-4.3 parts titanium dioxide.

[0006] Furthermore, the total mass of granite tailings and lead-zinc tailings accounts for 55–63 wt% of the total mass of the raw materials.

[0007] The above-mentioned method for preparing microcrystalline glass based on composite tailings includes the following steps:

[0008] Step 1: Weigh the raw materials according to the weight ratio, mix them evenly, ball mill them, dry them, and sieve them.

[0009] Step 2: Place the material obtained in Step 1 into a tableting mold and press it into a round tablet;

[0010] Step 3: The circular sheet obtained in Step 2 is heated in steps to 1450-1480℃ and held at that temperature to obtain molten glass.

[0011] Step four: Pour the molten glass into a preheated graphite mold. The formed glass is then annealed at 590-610°C to relieve stress and obtain the base glass.

[0012] Step 5: Nucleate the product obtained in Step 4 at 680-730℃ and hold, then continue heating to 1050-1100℃ for crystallization and hold.

[0013] Step six: Cool the material obtained in step five in the furnace, polish it, and obtain microcrystalline glass based on composite tailings.

[0014] Further, in step one, the ball milling speed is 350–400 r / min, the time is 40–60 min, the ball milling media is zirconia balls, and the material-to-ball ratio is 1:2–3. The drying temperature is 100–105℃, the drying time is 4–6 h, and the material is passed through a 200–325 mesh sieve.

[0015] Furthermore, in step two, the thickness of the disc is 3–5 mm.

[0016] Furthermore, in step three, the stepped heating regime is as follows: heat up to 1000-1050℃ at 8-10℃ / min, heat up to 1200-1300℃ at 4-5℃ / min, hold for 30-40min, heat up to 1450-1480℃ at 2-3℃ / min, and hold for 120-150min.

[0017] Furthermore, in step four, the graphite mold is preheated at 590–610°C for 5–10 minutes.

[0018] Furthermore, in step five, the nucleation holding time is 90–120 min. The crystallization holding time is 90–120 min.

[0019] Preparation principle: The main components of aluminum-silicon wastes such as granite tailings and lead-zinc tailings are similar to those of glass raw materials. They can partially or completely replace the SiO2, Al2O3, and CaO required for glass production, greatly reducing the production cost of microcrystalline glass. The TiO2 and Fe2O3 components contained in the tailings can act as nucleating agents to promote the nucleation and crystallization of the base glass. The tailings contain a high content of alkali metal oxides, which can act as fluxes to effectively reduce the glass melting temperature, greatly reducing the energy consumption of microcrystalline glass melting and resulting in high economic benefits. At the same time, microcrystalline glass can utilize its special structure of coexistence of crystalline and amorphous phases to provide a dual barrier of chemical solidification and physical encapsulation against the leaching of heavy metal elements in the tailings, effectively reducing the risk of heavy metal leaching.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0021] 1. It helps reduce the large-scale stockpiling of tailings resources, effectively improves the comprehensive utilization rate of tailings resources, and has a low heavy metal content, making it suitable for use in building materials.

[0022] 2. Using granite tailings and lead-zinc tailings to replace chemical raw materials in the production of microcrystalline glass not only greatly reduces the production cost of microcrystalline glass, but also reduces the melting temperature and holding time of microcrystalline glass by utilizing the low eutectic properties of metal elements in the tailings at high temperatures, thereby reducing energy consumption in the production process.

[0023] 3. The process of preparing microcrystalline glass by melting is simple, easy to operate, and the experimental conditions are easy to control. A stepped heating system is adopted during the melting process to ensure that the glass is fully melted at high temperature while minimizing the heating time and reducing unnecessary power consumption.

[0024] 4. The microcrystalline glass prepared by this invention has pyroxene as the main crystalline phase, with good crystallization, smooth and glossy surface, and dense structure. It effectively solidifies the harmful metal elements in lead-zinc tailings, reduces the risk of leaching of harmful elements during tailings storage, reduces the harm of tailings to the ecological environment and people's health, and realizes the harmless utilization of tailings resources. Attached Figure Description

[0025] Figure 1 This is the XRD pattern of the present invention. Detailed Implementation

[0026] Example 1

[0027] A method for preparing microcrystalline glass based on composite tailings includes the following steps:

[0028] (1) Weigh 40.5 parts of granite tailings, 22.5 parts of lead-zinc tailings, 15.3 parts of quartz sand, 9.6 parts of calcium oxide, 7.8 parts of magnesium oxide, and 4.2 parts of titanium dioxide. The total mass of granite tailings and lead-zinc tailings accounts for 63 wt% of the total mass of raw materials. Ball mill at 380 r / min for 50 min. The ball milling media is zirconia balls, and the material-to-ball ratio is 1:2. Dry at 100℃ for 6 h, pass through a 200 mesh sieve, and grind and mix thoroughly.

[0029] (2) Take an appropriate amount of the material obtained in step (1) and put it into the tableting mold to press it into a round sheet. The diameter of the round sheet is 40 mm and the thickness is 4 mm.

[0030] (3) Place the round piece obtained in step (2) into a blast furnace box furnace, heat it to 1000℃ at 10℃ / min, heat it to 1250℃ at 5℃ / min, hold it for 35min, heat it to 1460℃ at 3℃ / min, hold it for 2h, and obtain molten glass liquid.

[0031] (4) The molten glass was poured into a graphite mold that was preheated to 600°C for 8 minutes. The formed glass was then annealed at 600°C for 2 hours to relieve stress and obtain the base glass.

[0032] (5) Nucleate the base glass at 680℃ for 2 hours, and then continue to raise the temperature to 1050℃ for crystallization and hold for 2 hours.

[0033] (6) The material obtained in step (5) is cooled in the furnace and polished to obtain a brownish-yellow microcrystalline glass based on composite tailings.

[0034] Example 2

[0035] A method for preparing microcrystalline glass based on composite tailings includes the following steps:

[0036] (1) Weigh out 36.9 parts of granite tailings, 18.4 parts of lead-zinc tailings, 19.4 parts of quartz sand, 12.9 parts of calcium oxide, 8.1 parts of magnesium oxide, and 4.3 parts of titanium dioxide. The total mass of granite tailings and lead-zinc tailings accounts for 55.3 wt% of the total mass of raw materials. Ball mill at 380 r / min for 50 min. The ball milling media is zirconia balls with a material-to-ball ratio of 1:2. Dry at 100℃ for 6 h, pass through a 200 mesh sieve, and grind and mix thoroughly.

[0037] (2) Take an appropriate amount of the material obtained in step (1) and put it into the tableting mold to press it into a round sheet. The diameter of the round sheet is 40 mm and the thickness is 4 mm.

[0038] (3) Place the round piece obtained in step (2) into a blast furnace box furnace, heat it to 1000℃ at 10℃ / min, heat it to 1250℃ at 5℃ / min, hold it for 35min, heat it to 1460℃ at 3℃ / min, hold it for 2h, and obtain molten glass liquid.

[0039] (4) The molten glass was poured into a graphite mold that was preheated to 600°C for 8 minutes. The formed glass was then annealed at 600°C for 2 hours to relieve stress and obtain the base glass.

[0040] (5) Nucleate the base glass at 680℃ for 2 hours, and then continue to raise the temperature to 1050℃ for crystallization and hold for 2 hours.

[0041] (6) The material obtained in step (5) is cooled in the furnace and polished to obtain a brownish-yellow microcrystalline glass based on composite tailings.

[0042] Example 3

[0043] A method for preparing microcrystalline glass based on composite tailings includes the following steps:

[0044] (1) Weigh out 38.5 parts of granite tailings, 19.3 parts of lead-zinc tailings, 20.2 parts of quartz sand, 12.4 parts of calcium oxide, 8.5 parts of magnesium oxide, and 0 parts of titanium dioxide. The total mass of granite tailings and lead-zinc tailings accounts for 57.8 wt% of the total mass of raw materials. Ball mill at 380 r / min for 50 min. The ball milling media is zirconia balls with a material-to-ball ratio of 1:2. Dry at 100℃ for 6 h, pass through a 200 mesh sieve, and grind and mix thoroughly.

[0045] (2) Take an appropriate amount of the material obtained in step (1) and put it into the tableting mold to press it into a round sheet. The diameter of the round sheet is 40 mm and the thickness is 4 mm.

[0046] (3) Place the round piece obtained in step (2) into a blast furnace box furnace, heat it to 1000℃ at 10℃ / min, heat it to 1250℃ at 5℃ / min, hold it for 35min, heat it to 1460℃ at 3℃ / min, hold it for 2h, and obtain molten glass liquid.

[0047] (4) The molten glass was poured into a graphite mold that was preheated to 600°C for 8 minutes. The formed glass was then annealed at 600°C for 2 hours to relieve stress and obtain the base glass.

[0048] (5) Nucleate the base glass at 730℃ for 2 hours, and then continue to raise the temperature to 1100℃ for crystallization and hold for 2 hours.

[0049] (6) The material obtained in step (5) is cooled in the furnace and polished to obtain green microcrystalline glass based on composite tailings.

[0050] Table 1. Bulk density and water absorption rate of microcrystalline glass

[0051] Test Project Example 1 Example 2 Example 3 <![CDATA[Bulk density (×10 3 kg / m 3 )]]> 2.826 2.831 2.821 24-hour water absorption rate (%) 0.047 0.042 0.047

[0052] Table 2. Leaching concentration of harmful elements in microcrystalline glass

[0053] Leaching concentration (mg / L) Example 1 Example 2 Example 3 GB 5085.3—2007 standard Zn 0.0291 <0.02 0.0339 100 Mn 0.0347 0.0285 0.0453 - Pb <0.02 <0.02 <0.02 5

[0054] The microcrystalline glasses prepared in Examples 1-3 were subjected to X-ray diffraction analysis, and the XRD diffraction patterns are shown in the attached figures. Figure 1 As shown, the microcrystalline glass prepared in Examples 1 and 2 uses titanium dioxide as a nucleating agent, attracting oxygen ions to aggregate and achieve phase separation, inducing nucleation and crystallization of the glass. Therefore, the microcrystalline glass has pyroxene (PDF#88-0833) as the main crystalline phase, and crystallization is good. The microcrystalline glass prepared in Example 3 uses only iron oxide contained in tailings as a nucleating agent. An iron-rich phase first appears in the glass, which then promotes the precipitation of the pyroxene (PDF#74-2424) main crystalline phase. (From the attached...) Figure 1 It is evident that the diffraction peak intensities of Examples 1 and 2 are higher than those of Example 3, indicating that the combination of titanium dioxide and iron oxide as nucleating agents results in better glass crystallization performance.

[0055] The bulk density and water absorption rate of the microcrystalline glass prepared in Examples 1-3 are shown in Table 1 above, and the toxicity leaching test results are shown in Table 2 above.

[0056] As can be seen from the data in Table 1, the bulk density of the microcrystalline glass is 2.82 × 10⁻⁶. 3 kg / m 3 The water absorption rate is less than 0.05%. Table 2 shows that the leaching concentrations of heavy metals such as Zn, Mn, and Pb in the microcrystalline glass are all far below the national standard limits. Therefore, the microcrystalline glass has excellent curing effect on heavy metals in tailings, exhibiting superior performance and meeting the requirements.

[0057] Example 4

[0058] A method for preparing microcrystalline glass based on composite tailings includes the following steps:

[0059] (1) Weigh 37.2 parts of granite tailings, 20.3 parts of lead-zinc tailings, 17.1 parts of quartz sand, 10.7 parts of calcium oxide, 8 parts of magnesium oxide, and 2.1 parts of titanium dioxide. The total mass of granite tailings and lead-zinc tailings accounts for 60.2 wt% of the total mass of raw materials. Ball mill at 350 r / min for 40 min. The ball milling media is zirconia balls with a material-to-ball ratio of 1:3. Dry at 105℃ for 4 h, pass through a 300 mesh sieve, and grind and mix thoroughly.

[0060] (2) Take an appropriate amount of the material obtained in step (1) and put it into the tableting mold to press it into a round sheet. The diameter of the round sheet is 40mm and the thickness is 3mm.

[0061] (3) Place the disc obtained in step (2) into a blast furnace box furnace, heat it to 1050°C at 8°C / min, heat it to 1300°C at 4°C / min, hold it for 30 min, heat it to 1450°C at 2°C / min, hold it for 135 min, and obtain molten glass.

[0062] (4) Pour the molten glass into a graphite mold that has been preheated to 590°C for 5 minutes. After forming, the glass is annealed at 590°C for 2 hours to relieve stress and obtain the base glass.

[0063] (5) Nucleate the base glass at 730℃ for 90 minutes, and then continue to raise the temperature to 1100℃ for crystallization and hold for 90 minutes.

[0064] (6) The material obtained in step (5) is cooled in the furnace and polished to obtain microcrystalline glass based on composite tailings.

[0065] Example 5

[0066] A method for preparing microcrystalline glass based on composite tailings includes the following steps:

[0067] (1) Weigh 39.6 parts of granite tailings, 21.4 parts of lead-zinc tailings, 18.5 parts of quartz sand, 11.3 parts of calcium oxide, 8.3 parts of magnesium oxide, and 1.2 parts of titanium dioxide. The total mass of granite tailings and lead-zinc tailings accounts for 61 wt% of the total mass of raw materials. Ball mill at 400 r / min for 60 min. The ball milling media is zirconia balls, and the material-to-ball ratio is 1:3. Dry at 103℃ for 5 h, pass through a 325 mesh sieve, and grind and mix thoroughly.

[0068] (2) Take an appropriate amount of the material obtained in step (1) and put it into the tableting mold to press it into a round sheet. The diameter of the round sheet is 40mm and the thickness is 5mm.

[0069] (3) Place the disc obtained in step (2) into a blast furnace box furnace, heat it to 1025°C at 9°C / min, heat it to 1200°C at 4°C / min, hold it for 40 min, heat it to 1480°C at 2°C / min, hold it for 2.5 h, and obtain molten glass liquid;

[0070] (4) The molten glass was poured into a graphite mold that was preheated to 610℃ for 10 min. The formed glass was then annealed at 610℃ for 2 h to relieve stress and obtain the base glass.

[0071] (5) Nucleate the base glass at 710℃ for 105 min, and then continue to raise the temperature to 1070℃ for crystallization and hold for 105 min.

[0072] (6) The material obtained in step (5) is cooled in the furnace and polished to obtain microcrystalline glass based on composite tailings.

[0073] Comparative Example 1

[0074] The remaining steps of this comparative example are the same as those in Example 1, except that the stepped heating process in step (3) is replaced with a direct heating to 1450℃ and holding for 2 hours, and Sb2O3 is used as a clarifying agent. The resulting glass-ceramic bulk density was 2.729 × 10⁻⁶. 3 kg / m 3 This invention demonstrates that the optimized melting and heating process allows for better melting and mixing of glass raw materials, thereby improving the performance of the finished microcrystalline glass.

[0075] Comparative Example 2

[0076] Chinese invention patent CN 104773958 A discloses a method for preparing calcium iron pyroxene microcrystalline glass from lead slag. The method uses lead slag containing heavy metals to prepare the microcrystalline glass, and the phase composition of the finished product is calcium iron pyroxene and silica. The minimum Pb leaching concentration is 0.028 mg / L, and the minimum Zn leaching concentration is 1.04 mg / L. The remaining steps in this comparative example are the same as in Example 1, except that the iron oxide content in the raw materials exceeds 16%. It is evident that by adjusting the basic glass composition and preventing excessive iron oxide incorporation, the main crystalline phase of the microcrystalline glass can be controlled, thereby improving the curing effect of heavy metals on the microcrystalline glass and effectively reducing the leaching risk of heavy metals in the microcrystalline glass.

Claims

1. A method for preparing microcrystalline glass based on composite tailings, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the weight ratio, ball mill, dry and sieve; Step 2: Place the material obtained in Step 1 into a tableting mold and press it into a round tablet; Step 3: The circular sheet obtained in Step 2 is heated in steps to 1450~1480℃ and held at that temperature to obtain molten glass. Step 4: Pour the molten glass into a preheated graphite mold, and anneal the formed glass at 590~610℃. Step 5: Nucleate the product obtained in Step 4 at 680~730℃ and hold, then continue to raise the temperature to 1050~1100℃ for crystallization and hold. Step six: Cool the material obtained in step five in the furnace, polish and grind it to obtain microcrystalline glass based on composite tailings; In step three, the stepped heating regime is as follows: heat up to 1000-1050℃ at 8-10℃ / min, heat up to 1200-1300℃ at 4-5℃ / min, hold for 30-40min, heat up to 1450-1480℃ at 2-3℃ / min, and hold for 120-150min; The microcrystalline glass based on composite tailings comprises the following raw materials in parts by weight: 36.9-40.5 parts granite tailings, 18.4-22.5 parts lead-zinc tailings, 15.3-20.2 parts quartz sand, 9.6-12.9 parts calcium oxide, 7.8-8.5 parts magnesium oxide, and 0-4.3 parts titanium dioxide. The leaching concentration of Pb in the microcrystalline glass is less than 0.02 mg / L.

2. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: The total mass of the granite tailings and lead-zinc tailings accounts for 55-63 wt% of the total mass of the raw materials.

3. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: In step one, the ball milling speed is 350~400 r / min, the time is 40~60 min, the ball milling medium is zirconia balls, and the material-to-ball ratio is 1:2~3.

4. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: In step one, the drying temperature is 100~105℃, the drying time is 4~6h, and the product is passed through a 200~325 mesh sieve.

5. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: In step two, the thickness of the disc is 3-5 mm.

6. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: In step four, the graphite mold is preheated at 590~610℃ for 5~10 minutes.

7. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: In step five, the nucleation and heat preservation time is 90-120 minutes.

8. The method for preparing microcrystalline glass based on composite tailings according to claim 1, characterized in that: In step five, the crystallization and heat preservation time is 90~120 minutes.

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