A method for preparing microcrystalline glass based on the combined utilization of lithium tailings and titanium tailings

Abstract

This invention provides a method for preparing microcrystalline glass based on the composite utilization of lithium tailings and titanium tailings, belonging to the field of tailings processing technology. This invention leverages the complementary chemical composition of the two types of tailings, combining them in a specific ratio for glass preparation. Lithium tailings primarily provide SiO2 and Al2O3 to construct the glass network framework, with Na2O and K2O acting as fluxes to promote melting. Titanium tailings introduce TiO2 and Fe2O3 as composite nucleating agents to promote crystal precipitation. The process includes raw material mixing, high-temperature melting (1400–1470℃), forming annealing (550℃), and stepwise heat treatment (nucleation: 700–780℃; crystallization: 1000–1070℃). The method provided by this invention eliminates the need for external nucleating agents, significantly improving tailings utilization and solidifying harmful elements during sintering, thus reducing environmental risks. The resulting microcrystalline glass exhibits a dense structure and excellent mechanical and corrosion resistance properties, making it suitable for applications in architectural decoration and functional ceramics.

Description

Technical Field

[0001] This invention belongs to the field of tailings processing technology, specifically relating to a method for preparing microcrystalline glass based on the composite utilization of lithium tailings and titanium tailings. Background Technology

[0002] Lithium tailings and titanium tailings are solid wastes generated during mineral beneficiation. The main mineral phases of lithium tailings are quartz, feldspar (albite and potassium feldspar), and a small amount of mica. Their chemical composition is primarily SiO2 and Al2O3, with some Na2O and K2O, which can serve as glass network forming materials and fluxing components. Titanium tailings, on the other hand, have a more complex mineral composition, typically containing TiO2 in the form of ilmenite or ilmenite, as well as Fe2O3 components such as hematite and magnetite, and may also contain small amounts of silicate minerals. Currently, these tailings are generally stockpiled in tailings ponds or used for simple backfilling, leading to the long-term idleness and waste of resources such as silicon, aluminum, sodium, potassium, iron, and titanium. Furthermore, due to the presence of trace heavy metals and residual beneficiation reagents, these tailings may seep into the soil and groundwater through rainwater leaching, posing a potential long-term risk to the regional ecological environment. Existing research on the comprehensive utilization of lithium and titanium tailings mainly focuses on the recovery of valuable metals or their use as aggregates in building materials. However, the overall amount of tailings consumed is limited, making it difficult to fundamentally solve the pressure of the continuously expanding scale of tailings storage.

[0003] Microcrystalline glass is a class of inorganic non-metallic materials prepared by controlling the nucleation and grain growth of a glass matrix. It combines the homogeneity of glass with the high strength and high crystallinity of ceramics, exhibiting excellent mechanical properties, thermal stability, and designable optical, electrical, and chemical characteristics. The high SiO2 and Al2O3 content, along with a certain amount of alkali metal oxides, in lithium tailings make it highly compatible with the basic composition of microcrystalline glass. Meanwhile, TiO2 and Fe2O3 in titanium tailings are typical and highly efficient nucleating agents that can be used to promote crystalline phase precipitation and improve the structure and properties of microcrystalline glass. Therefore, the synergistic utilization of lithium and titanium tailings has significant raw material complementarity, providing glass network precursors and nucleating agent systems for microcrystalline glass, thus realizing the large-scale resource utilization of tailings.

[0004] Current research has attempted to prepare microcrystalline glass using single-type tailings, but these methods generally rely on large amounts of added pure chemical raw materials to adjust the composition. For example, Chinese patent (CN108863088A) uses spodumene tailings as the main raw material, adding various auxiliary materials such as soda ash, quartz sand, and magnesium oxide to achieve a suitable formulation; Chinese patent (CN104926131A) uses vanadium-titanium magnetite as the main raw material, using quartz sand, limestone, and soda ash as auxiliary materials to regulate the glass network structure, with the vanadium-titanium magnetite tailings content ranging from 50.0% to 65.0 wt.%. These methods not only increase the cost of additional raw materials but also have a limited tailings utilization rate, failing to fully utilize the complementary properties of the tailings.

[0005] Therefore, developing a new technology for the synergistic preparation of microcrystalline glass using lithium and titanium tailings, coupling the advantages of both types of tailings to reduce additive usage, lower melting energy consumption, and improve tailings utilization rate, is an important direction for achieving high-value utilization of solid waste. This technology can effectively reduce the scale of tailings stockpiles, lower potential environmental pollution risks, and obtain microcrystalline glass materials with engineering application value, thus possessing significant environmental, economic, and social benefits. However, how to develop corresponding microcrystalline glass that does not require the addition of nucleating agents and can significantly improve tailings utilization rate remains an urgent technical problem to be solved. Summary of the Invention

[0006] This invention aims to solve the aforementioned technical problems by providing a method for preparing microcrystalline glass based on the combined utilization of lithium and titanium tailings. The objective of this invention is to improve tailings resource utilization efficiency and reduce energy consumption through the synergistic utilization of lithium and titanium tailings. Furthermore, it eliminates the need for external nucleating agents, significantly increasing tailings utilization and enabling the preparation of microcrystalline glass with a dense structure, excellent mechanical and corrosion resistance, suitable for applications in architectural decoration and functional ceramics.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: This invention first provides a method for preparing microcrystalline glass based on the combined utilization of lithium tailings and titanium tailings, comprising the following steps: S1. Weigh the required raw materials, which are lithium tailings, titanium tailings and boron trioxide in a weight ratio of (28-55):(40-70):(2-5), and then put them into a planetary ball mill for grinding until they are mixed evenly. S2. The mixed raw materials are heated to a molten state in a high-temperature furnace to obtain molten glass; S3. Pour the molten glass into a stainless steel mold to set its shape, and then anneal it in a box furnace until it cools to room temperature; S4. The shaped glass is subjected to nucleation and crystallization treatments, and finally slowly cooled to room temperature.

[0008] The method provided by this invention utilizes lithium tailings, where SiO2 provides the necessary components for the basic glass network, Al2O3 constitutes the glass's skeletal structure, and Na2O and K2O act as fluxes to effectively lower the melting temperature. Titanium tailings provide key functional components for the performance of the microcrystalline glass, with TiO2 and Fe2O3 forming a composite nucleus system that promotes crystal phase formation through a dual mechanism of induced phase separation and heterogeneous nucleation. This method, through the synergistic utilization of lithium and titanium tailings, improves tailings resource utilization efficiency, reduces energy consumption, and eliminates the need for external nucleating agents. It significantly increases tailings utilization and can produce microcrystalline glasses with dense structures, excellent mechanical and corrosion resistance, suitable for applications in building decoration and functional ceramics.

[0009] Furthermore, the combined chemical composition of the lithium tailings and titanium tailings mentioned in step S1 includes: SiO2 45.38–55.15 wt.%; Al2O3 12.28–12.92 wt.%; Fe2O3 5.79–9.99 wt.%; Na2O 2.75–3.87 wt.%; K2O 0.74–1.49 wt.%; CaO 5.39–9.19 wt.%; MgO 4.67–8.16 wt.%; TiO2 2.28–3.99 wt.%.

[0010] Furthermore, in step S1, the particle size of the two tailings raw materials is no greater than 200 mesh, and the moisture content is no higher than 5%.

[0011] Furthermore, in step S2, the heating rate during the melting stage is 5 °C / min, the melting temperature is 1400–1470 °C, and the melting time is 2 h.

[0012] Furthermore, in step S4, the nucleation process involves holding the temperature at 700–780 °C for 2 hours, and the crystallization process involves holding the temperature at 1000–1070 °C for 2 hours.

[0013] The second objective of this invention is to provide a microcrystalline glass prepared by the method described above, wherein the raw materials for the microcrystalline glass are lithium tailings, titanium tailings and boron trioxide in a weight ratio of (28-55):(40-70):(2-5).

[0014] Furthermore, SiO2, Al2O3, Na2O, and K2O in lithium tailings serve as the glass matrix network and flux, while TiO2 and Fe2O3 in titanium tailings act as nucleation components, promoting the formation of the crystal phase in the glass-ceramic.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Raw material synergy and cost advantage: It makes full use of the complementary chemical composition of lithium tailings (rich in network formations and fluxes) and titanium tailings (rich in nucleating agents), without the need for additional nucleating agents. This design allows the total amount of tailings to reach more than 95 wt.% of the raw materials, greatly improving the efficiency of solid waste resource utilization and realizing "waste treatment".

[0016] (2) Simplified process and energy saving and environmental protection: Glass formation and crystallization are achieved by utilizing the components of the tailings themselves, which simplifies the batching system; at the same time, the method can effectively solidify harmful elements such as heavy metals in the tailings through high-temperature sintering process, reducing environmental risks and having significant environmental benefits.

[0017] (3) Excellent product performance: The microcrystalline glass phase prepared is pyroxene, the product has a dense structure, high mechanical strength, excellent wear resistance and corrosion resistance, and can be widely used in building decoration, industrial wear-resistant parts and functional ceramics. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described in detail below with reference to embodiments. It should be noted that the following embodiments are for explanation and illustration only and are not intended to limit the invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description are still within the scope of protection of this invention.

[0019] In the embodiments of this invention, the lithium tailings and titanium tailings used had a particle size of +0.075 μm accounting for 75.16% and 68.42%, respectively, and a tailings moisture content of 1.36% and 1.48%, respectively. During the raw material preparation process, the tailings need to be further crushed and ground to further increase the reaction area and accelerate melting. The chemical compositions of the lithium tailings and titanium tailings are shown in Tables 1 and 2, respectively.

[0020] Table 1 Chemical composition of lithium tailings (%)

[0021] Table 2 Chemical composition of titanium tailings (%)

[0022] Example 1

[0023] A lithium-titanium tailings-based microcrystalline glass comprises, by weight, 28 parts lithium tailings, 70 parts titanium tailings, and 2 parts B2O3.

[0024] The above-mentioned method for preparing microcrystalline glass includes the following steps: (1) Weigh the raw materials according to the above formula, and grind the raw materials in a planetary ball mill for 1 h to obtain a uniform mixture. Take 50 g of the mixture and place it in a corundum crucible and put it in a muffle furnace. Heat the mixture to 1400 ℃ at a heating rate of 5 ℃ / min and hold it for 2 h. Pour the molten and clarified glass liquid into a stainless steel mold for shaping, and then anneal it in a box furnace at 550 ℃ for 2 h. Cool it to room temperature with the furnace temperature to obtain the base glass.

[0025] (2) The base glass was placed in a muffle furnace and heated to 700 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete nucleation, and then heated to 1000 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete the crystallization process. Finally, it was cooled to room temperature to obtain lithium-titanium tailings-based microcrystalline glass. The results of the sample bulk density, flexural strength, compressive strength and acid-base mass loss test are shown in Table 3.

[0026] Example 2

[0027] A lithium-titanium tailings-based microcrystalline glass comprises, by weight, 37 parts lithium tailings, 60 parts titanium tailings, and 3 parts B2O3.

[0028] The above-mentioned method for preparing microcrystalline glass includes the following steps: (1) Weigh the raw materials according to the above formula, and grind the raw materials in a planetary ball mill for 1 h to obtain a uniform mixture. Take 50 g of the mixture and place it in a corundum crucible and put it in a muffle furnace. Heat the mixture to 1430 ℃ at a heating rate of 5 ℃ / min and hold it for 2 h. Pour the molten and clarified glass liquid into a stainless steel mold for shaping, and then anneal it in a box furnace at 550 ℃ for 2 h. Cool it to room temperature with the furnace temperature to obtain the base glass.

[0029] (2) The base glass was placed in a muffle furnace and heated to 720 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete nucleation, and then heated to 1030 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete the crystallization process. Finally, it was cooled to room temperature to obtain lithium-titanium tailings-based microcrystalline glass. The results of the sample bulk density, flexural strength, compressive strength and acid-base mass loss test are shown in Table 3.

[0030] Example 3

[0031] A lithium-titanium tailings-based microcrystalline glass comprises, by weight, 46 parts lithium tailings, 50 parts titanium tailings, and 4 parts B2O3.

[0032] The above-mentioned method for preparing microcrystalline glass includes the following steps: (1) Weigh the raw materials according to the above formula, and grind the raw materials in a planetary ball mill for 1 h to obtain a uniform mixture. Take 50 g of the mixture and place it in a corundum crucible and put it in a muffle furnace. Heat the mixture to 1450 ℃ at a heating rate of 5 ℃ / min and hold it for 2 h. Pour the molten and clarified glass liquid into a stainless steel mold for shaping, and then anneal it in a box furnace at 550 ℃ for 2 h. Cool it to room temperature with the furnace temperature to obtain the base glass.

[0033] (2) The base glass was placed in a muffle furnace and heated to 750 ℃ ​​at a heating rate of 5 ℃ / min, held for 2 h to complete nucleation, and then heated to 1050 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete the crystallization process. Finally, it was cooled to room temperature to obtain lithium-titanium tailings-based microcrystalline glass. The results of the sample bulk density, flexural strength, compressive strength and acid-base mass loss test are shown in Table 3.

[0034] Example 4

[0035] A lithium-titanium tailings-based microcrystalline glass comprises, by weight, 55 parts lithium tailings, 40 parts titanium tailings, and 5 parts B2O3.

[0036] The above-mentioned method for preparing microcrystalline glass includes the following steps: (1) Weigh the raw materials according to the above formula, and grind the raw materials in a planetary ball mill for 1 h to obtain a uniform mixture. Take 50 g of the mixture and place it in a corundum crucible and put it in a muffle furnace. Heat the mixture to 1470 ℃ at a heating rate of 5 ℃ / min and hold it for 2 h. Pour the molten and clarified glass liquid into a stainless steel mold for shaping, and then anneal it in a box furnace at 550 ℃ for 2 h. Cool it to room temperature with the furnace temperature to obtain the base glass.

[0037] (2) The base glass was placed in a muffle furnace and heated to 780 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete nucleation, and then heated to 1070 ℃ at a heating rate of 5 ℃ / min, held for 2 h to complete the crystallization process. Finally, it was cooled to room temperature to obtain lithium-titanium tailings-based microcrystalline glass. The results of the sample bulk density, flexural strength, compressive strength and acid-base mass loss test are shown in Table 3.

[0038] Table 3 Performance indicators of the microcrystalline glass of the present invention

[0039] Comparative Example 1 Compared to Example 1, this comparative example uses 56-74% spodumene, 2.5-6.2% sodium fluorosilicate, 1.2-6.0% soda ash, 4.5-11.2% light-burned magnesia, and 5.5-23.5% quartz sand as raw materials to prepare microcrystalline glass using a melt rolling method. This method has high energy consumption, requires the addition of various auxiliary materials, and the solid waste utilization rate is only 56-74%.

[0040] Comparative Example 2 Compared to Example 1, this comparative example uses vanadium-titanium magnetite tailings as the main raw material, with a tailings content of 50.0-65.0 wt.% and auxiliary raw materials accounting for 35.0-45.0 wt.%, while also requiring the addition of 0.5-5.0 wt.% fluxing and clarifying agent. This method not only requires the addition of multiple auxiliary materials but also employs a stepped annealing process, resulting in a long processing time.

[0041] Comparative Example 3 Compared to Example 1, this comparative example uses nickel-iron slag and iron tailings as the main raw materials to synergistically prepare microcrystalline glass, with a melting temperature of 1560–1600℃. The prepared samples have a density of 3.08–3.13 g / cm³, acid resistance >99.75%, alkali resistance >99.59%, flexural strength of 151–153 MPa, and Vickers hardness of 9.09–9.22 GPa. The test results show that while ensuring the performance of the example samples reaches the level of the comparative example, the example significantly reduces the melting temperature, thereby effectively reducing energy consumption, while the comparative example scheme cannot achieve the same effect.

Claims

1. A method for preparing microcrystalline glass based on the composite utilization of lithium tailings and titanium tailings, characterized in that, Includes the following steps: S1. Weigh the required raw materials, which are lithium tailings, titanium tailings and boron trioxide in a weight ratio of (28-55):(40-70):(2-5), and then put them into a planetary ball mill for grinding until they are mixed evenly. S2. The mixed raw materials are heated to a molten state in a high-temperature furnace to obtain molten glass; S3. Pour the molten glass into a stainless steel mold to set its shape, and then anneal it in a box furnace until it cools to room temperature; S4. The shaped glass is subjected to nucleation and crystallization treatments, and finally slowly cooled to room temperature.

2. The microcrystalline glass according to claim 1, characterized in that, The combined chemical composition of the lithium tailings and titanium tailings mentioned in step S1 includes: SiO2 45.38–55.15 wt.%; Al2O3 12.28–12.92 wt.%; Fe2O3 5.79–9.99 wt.%; Na2O 2.75–3.87 wt.%; K2O 0.74–1.49 wt.%; CaO 5.39–9.19 wt.%; MgO 4.67–8.16 wt.%; TiO2 2.28–3.99 wt.%.

3. The microcrystalline glass according to claim 1, characterized in that, In step S1, the particle size of the two tailings raw materials is no greater than 200 mesh, and the moisture content is no higher than 5%.

4. The method according to claim 1, characterized in that, In step S2, the heating rate during the melting stage is 5 °C / min, the melting temperature is 1400–1470 °C, and the melting time is 2 h.

5. The method according to claim 1, characterized in that, In step S4, the nucleation process involves holding the temperature at 700–780 °C for 2 hours, and the crystallization process involves holding the temperature at 1000–1070 °C for 2 hours.

6. The microcrystalline glass prepared by the method according to any one of claims 1-5, characterized in that, The raw materials for the microcrystalline glass are lithium tailings, titanium tailings and boron trioxide in a weight ratio of (28-55):(40-70):(2-5).

7. The microcrystalline glass according to claim 6, characterized in that, SiO2, Al2O3, Na2O and K2O in lithium tailings serve as the glass matrix network and flux, while TiO2 and Fe2O3 in titanium tailings serve as crystal nuclei, promoting the formation of the crystal phase in glass-ceramics.

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