High-performance beryllium slag glass ceramic and preparation method thereof

Abstract

The invention discloses high-performance beryllium slag glass ceramics and a preparation method thereof, and belongs to the field of solid waste recycling. The method comprises the following steps: firstly, drying various beryllium slag, and uniformly mixing the beryllium slag with other solid waste auxiliary materials in proportion to obtain a mixture; and then, melting the mixture at a high temperature, and carrying out casting molding to obtain base glass and an alloy. Smoke generated in the mixture melting process is discharged after being subjected to dust removal and tail gas treatment and reaching the standard, and dust removal ash can be returned to the mixing process to be used as an ingredient. And carrying out annealing and heat treatment on the base glass to obtain the beryllium slag microcrystalline glass. The prepared beryllium slag glass ceramic has the excellent performance that the average grain size is smaller than or equal to 5 microns, the beryllium leaching concentration is smaller than 0.02 mg / L, the bending strength is larger than or equal to 80 MPa, the volume density is larger than or equal to 2.60 g / cm < 3 >, the water absorption rate is smaller than or equal to 0.1%, and the beryllium slag glass ceramic can be widely applied to the fields of metallurgy, buildings, mechanical engineering, chemical engineering and the like. The beryllium slag glass ceramic has the advantages of large beryllium slag absorption amount, good beryllium curing effect, high beryllium slag glass ceramic performance and the like.

Description

Technical Field

[0001] The present invention belongs to the field of comprehensive utilization of solid waste resources, and specifically discloses a high-performance beryllium slag glass-ceramics and a preparation method thereof. Background Art

[0002] Beryllium is a grayish-white rare alkaline earth metal with excellent nuclear and physical properties, and has important applications in the fields of nuclear weapons, aerospace, medical detection, etc. However, beryllium and its compounds are all highly toxic, and the World Health Organization lists it as a Class I carcinogen. Beryllium slag refers to the molten slag, dust collected by a dust collection device or wastewater treatment sludge generated during the production of beryllium and its compounds. For example, when extracting beryllium from beryllium ore industrially, the dust generated by the high-temperature melting of beryllium ore is called beryllium-calcium slag, and the filter residue after acid leaching of the molten slag is beryllium-silicon slag; during the subsequent extraction and separation process of beryllium-containing leaching solution, beryllium alum slag and beryllium-iron slag are respectively generated; and during the preparation of beryllium fluoride and the production of metallic beryllium, etc., fluoroberyllium slag will be generated. The residual beryllium content in beryllium slag is generally 0.1-0.5%.

[0003] According to the "National List of Hazardous Wastes" (2021 Edition), beryllium slag belongs to hazardous waste of HW20 category. Under the current technical conditions, there is no scientific disposal method for beryllium slag, and most of it is directly put into a storage depot. When exposed to rain, the water-soluble beryllium in beryllium slag will dissolve in water and enter the soil, groundwater, rivers, etc., causing serious environmental pollution, and then increasing the risk of human Be intake and endangering public safety. With the growth of the country's demand for beryllium products, beryllium slag is also increasing exponentially. To solve the problems of existing beryllium slag overstocking and the disposal of newly added beryllium slag, it is urgent to develop an economically feasible beryllium slag disposal technology.

[0004] At present, the harmless treatment and resource utilization of beryllium slag mainly focus on aspects such as the secondary extraction of beryllium and the preparation of cement clinker, etc., and there are problems such as high risk of beryllium leaching, inability to achieve the reduction and large-scale treatment of beryllium slag, high cost, and low value of products. Chinese Invention Patent (CN109706327A) discloses a method for harmlessly treating beryllium slag. In this method, the soluble beryllium salt in the beryllium slag is roasted into beryllium oxide by traditional lead-smelting technology and is coated by the slag, which can achieve the reduction and harmlessness of beryllium slag. However, the beryllium slag content only accounts for 5-15% of the total smelting materials, the co-disposal amount is relatively low and the risk of beryllium leaching is relatively high. Chinese Invention Patent (CN109761514A) discloses a beryllium slag detoxification and cement kiln co-resource treatment system and process. In this process, the beryllium slag is washed with water under acidic conditions to obtain a beryllium sulfate solution for recovering beryllium hydroxide, and the remaining solid slag is used as cement clinker through high-temperature calcination, which can achieve the recovery of beryllium and the resource utilization of the waste slag. However, the overall process flow is relatively complex and the cost is relatively high. Chinese Invention Patent (CN116282978A) discloses a method for resourcefully disposing of beryllium-containing silicon slag and its application. In this method, the beryllium-containing silicon slag is mixed evenly with coal and roasted at high temperature. The obtained roasted sample has a lower leaching toxicity and can be used for the preparation of cement clinker admixture. However, this method is only applicable to beryllium-containing silicon slag and the added value of the obtained product is relatively low.

[0005] Glass-ceramics is a two-phase composite material composed of a crystalline phase and a glass phase, and can be prepared by controlled nucleation and crystallization of a base glass with a specific composition. Glass-ceramics has advantages such as high mechanical strength, high chemical stability, and good wear resistance, and is widely used in fields such as aerospace, metallurgy, construction, electronics, and biomedicine. The nucleation of glass-ceramics is mainly heterogeneous nucleation. During the preparation process, components such as oxides (Cr2O3, ZrO, Fe2O3), fluorides, and high-melting-point substances of high-field-strength cations in hazardous waste can act as nucleating agents to provide nucleation sites. Toxic elements can enter the glass-ceramics and be solidified under the combined action of the glass phase and the crystalline phase. Due to the ability to solidify toxic elements and obtain high-added-value products, glass-ceramics solidification has become one of the important methods for the green treatment and resource utilization of hazardous waste.

[0006] Chinese invention patent (CN108640523A) discloses a method for preparing glass-ceramics by synergistically pickling sludge with waste incineration ash residue. This method uses waste incineration ash residue as the main raw material and pickled sludge as the nucleating agent, and obtains glass-ceramics with low leaching toxicity and high performance through melting-one-step heat treatment. At the same time, harmless treatment and high-value utilization of two hazardous wastes, waste incineration ash residue and pickled sludge, are realized. Chinese invention patent (CN104261667A) discloses a method for preparing glass-ceramics using lithium-beryllium tailings. This method uses lithium-beryllium tailings as the main raw material and prepares glass-ceramics with good mechanical properties through melting-two-step heat treatment, providing a technical approach for the efficient utilization of lithium-beryllium tailings. However, lithium-beryllium tailings do not contain volatile beryllium components, belong to general solid waste, are relatively simple to process, and the maximum addition amount of tailings in this method is only 47.4%.

[0007] In contrast, beryllium slag contains a large amount of volatile substances, and beryllium exists in unstable forms such as sulfates and hydroxides. This makes the treatment of beryllium slag not only consider the performance of the final product, but also pay attention to the solidification effect of beryllium and avoid pollution. Existing methods cannot meet the treatment requirements of beryllium slag. Therefore, it is urgent to study a method for preparing glass-ceramics based on beryllium slag to effectively solve the problems of beryllium solidification and environmental pollution control. Summary of the Invention

[0008] Aiming at the problems existing in the existing technologies for the harmless treatment and resource utilization of beryllium slag, the present invention provides a high-performance beryllium slag glass-ceramics and its preparation method, which can realize the preparation of high-performance beryllium slag glass-ceramics with no pollution, short process flow, and low energy consumption from beryllium slag.

[0009] The present invention is realized through the following technical solutions:

[0010] A high-performance beryllium slag glass-ceramics, characterized in that the raw materials of the beryllium slag glass-ceramics include: 35wt%-55wt% of beryllium-silicon slag, 0-20wt% of beryllium-calcium slag, 20wt%-40wt% of beryllium-vanadium slag, 5wt%-15wt% of beryllium-iron slag, 5wt%-15wt% of beryllium-fluoride slag, and 10wt%-20wt% of solid waste auxiliary materials, with a total of 100wt%; during the preparation process, a melt is obtained after melting and holding at a certain temperature, and after the melt is cast and formed, a base glass and an alloy are obtained. Then, annealing and heat treatment are carried out on the prepared base glass to obtain the high-performance beryllium slag glass-ceramics. The properties of the beryllium slag glass-ceramics are: average grain size ≤ 5 μm, beryllium leaching concentration < 0.02 mg / L, flexural strength ≥ 80 MPa, bulk density ≥ 2.60 g·cm -3 , water absorption rate ≤ 0.1%.

[0011] A preparation method for the high-performance beryllium slag glass-ceramics as described above, and the specific preparation steps are as follows:

[0012] (1) Drying: Dry beryllium slag such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium-fluoride slag and solid waste auxiliary materials.

[0013] (2) Mixing: Mix the dried beryllium slag and solid waste auxiliary materials in step (1) evenly according to a certain ratio to obtain a mixed material.

[0014] (3) Melting and casting: Melt the mixed material obtained in step (2) at a certain temperature and keep it warm to obtain a melt. After the melt is cast and formed, basic glass and alloy are obtained. The flue gas generated during the melting process of the mixed material is discharged after passing through dust removal and tail gas treatment up to the standard. The dust removal ash can be returned to the mixing process as batching.

[0015] (4) Annealing and heat treatment: Anneal the basic glass obtained in step (3) and perform heat treatment at a certain temperature to obtain beryllium slag glass-ceramics.

[0016] Further, the beryllium slag is composed of one or more of the molten slag generated during the production process of beryllium and its compounds, the dust collected by the dust collection (removal) device, and the wastewater treatment sludge. Among them, the beryllium-silicon slag with SiO2 content ≥ 50wt%, the beryllium-calcium slag with CaO content ≥ 40wt%, the beryllium-alum slag with Al2O3 content ≥ 20wt%, the beryllium-iron slag with Fe2O3 content ≥ 30wt%, and the beryllium-fluoride slag with F content ≥ 40wt%. The solid waste auxiliary materials are solid wastes or solid waste mixtures containing calcium, aluminum, and silicon, and can be one or more of solid wastes such as waste gypsum, fly ash, steel slag, blast furnace slag, and carbide slag.

[0017] Further, in the mixed material obtained by mixing beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium-fluoride slag and solid waste auxiliary materials, control SiO2 to be 20wt% - 40wt%, CaO to be 18wt% - 35wt%, Al2O3 to be 5wt% - 20wt%, Fe2O3 to be 2 - 10wt%, and F to be 5wt% - 15wt%.

[0018] Further, when melting, control the melting temperature of the mixed material to be 1300 - 1600 °C and the holding time to be 0.5 - 2h. The sulfur content in the melt after melting < 1%, and the melt viscosity < 200 Pa·s.

[0019] Further, when performing heat treatment on the basic glass, control the heat treatment temperature to be 700 - 1000 °C and the heat treatment time to be 0.5 - 3h.

[0020] The principle of the present invention is:

[0021] (1) The beryllium-silicon slag contains components such as SiO2 and can be used as a silicon source for preparing glass-ceramics; the beryllium-calcium slag contains components such as CaO and can be used as a calcium source for preparing glass-ceramics; the beryllium-aluminum slag contains components such as Al2O3 and can be used as an aluminum source for preparing glass-ceramics; the beryllium-iron slag and beryllium-fluoride slag contain components such as Fe2O3 and MgF2 and can be used as nucleating agents for glass-ceramics.

[0022] (2) The beryllium-silicon slag, beryllium-aluminum slag and beryllium-iron slag contain a large amount of sulfate components, and the S content in the melt will increase significantly during the melting process. The sulfur dissolved in the melt will cause phase separation of the base glass, generate bubbles or inclusions, and significantly affect the crystallization process of the base glass, resulting in a decline in the mechanical properties and beryllium solidification performance of the glass-ceramics. In order to reduce the influence of S and others on the properties of glass-ceramics, the method adopted in the present invention is as follows:

[0023] ① By adding other solid waste auxiliary materials to adjust the alkalinity of the mixture, while ensuring the crystallization performance of the base glass, the solubility of S in the glass melt is minimized.

[0024] ② Through a large number of experiments, the melting temperature and melting time of the mixture (1300 - 1600 °C / 0.5 - 2 h) are determined, effectively reducing the S content, improving the uniformity of the melt, and improving the quality of the base glass.

[0025] (3) The applicant found that Be is mainly distributed in the glass phase and grain boundaries of the beryllium-slag glass-ceramics, and the grain size will affect the beryllium solidification effect and the mechanical properties of the glass-ceramics. When the grain size is small, the mechanical properties of the beryllium-slag glass-ceramics are high, but Be is easily leached; when the grain size is large, the beryllium solidification effect is excellent, but the mechanical properties of the beryllium-slag glass-ceramics are poor. In the present invention, by setting the heat treatment system at 700 - 1000 °C / 0.5 - 3 h, the grain size is regulated within a certain range, so as to achieve the effect of synergistically improving the beryllium solidification effect and mechanical properties.

[0026] In summary, in the present invention: the beryllium slag provides the required components such as silicon, calcium, and aluminum, and by adding solid waste auxiliary materials to adjust the melt alkalinity and promote crystallization, the sulfur content is reduced and the melt uniformity is improved; Fe2O3 and MgF2 in the beryllium-iron slag and beryllium-fluoride slag promote the uniform growth of crystals, realizing the efficient preparation of glass-ceramics; by optimizing the heat treatment conditions, the grain size is accurately regulated, and then beryllium-slag glass-ceramics with excellent beryllium solidification effect and mechanical properties are obtained, while achieving low energy consumption and short process preparation.

[0027] The beneficial technical effects of the present invention:

[0028] (1) The method described in the present invention uses beryllium slag and solid waste auxiliary materials as raw materials to prepare beryllium-slag glass-ceramics, which can not only realize the preparation of beryllium-slag glass-ceramics with all solid waste as raw materials, but also the proportion of beryllium slag in the raw materials > 80%;

[0029] (2) The method of the present invention uses components such as Fe2O3 in beryllium iron slag and fluorine salts in fluorine beryllium slag as nucleating agents, which can significantly reduce the melting temperature of the mixture, the network polymerization degree of the base glass, and the crystallization activation energy, and achieve one-step crystallization of the base glass.

[0030] (3) By adding solid waste auxiliary materials to adjust the alkalinity of the mixture and controlling the melting process parameters, etc., the method of the present invention effectively reduces the sulfur content in the glass melt, avoids problems such as phase separation, bubbles or inclusions of the base glass caused by sulfur, and significantly improves the uniformity and overall quality of the beryllium slag glass-ceramics.

[0031] (4) By optimizing the heat treatment conditions, the method of the present invention precisely controls the grain size and improves the microstructure, thereby synergistically improving the beryllium solidification effect and mechanical properties of the beryllium slag glass-ceramics.

[0032] (5) The method of the present invention realizes the reduction, harmless treatment and high-value resource utilization of beryllium slag through high-temperature melting + heat treatment. Description of the Drawings

[0033] Figure 1 It is a schematic process flow diagram of preparing glass-ceramics from beryllium slag in an embodiment of the present invention. Detailed Embodiments

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] On the contrary, the present invention covers any alternatives, modifications, equivalent methods and solutions made within the spirit and scope of the present invention defined by the claims. Further, in order to enable the public to have a better understanding of the present invention, some specific details are described in detail in the following detailed description of the present invention. Those skilled in the art can fully understand the present invention without the description of these details.

[0036] Example 1

[0037] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Next, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 35wt%, 0wt%, 40wt%, 5wt%, 6wt% and 14wt%. Keep the mixture in a high-temperature furnace at 1600 °C for 0.5 h, and pour the obtained melt with sulfur content <1% and viscosity <200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 1000 °C for 0.5 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 5.0 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.019 mg / L, flexural strength 126 MPa, bulk density 3.06 g·cm -3 , water absorption rate 0.0043 %.

[0038] Example 2

[0039] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Next, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 37wt%, 3wt%, 35wt%, 7wt%, 7wt% and 11wt%. Keep the mixture in a high-temperature furnace at 1550 °C for 1 h, and pour the obtained melt with sulfur content <1% and viscosity <200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 950 °C for 1 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 4.6 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.014 mg / L, flexural strength 115 MPa, bulk density 2.95 g·cm -3 , water absorption rate 0.054 %.

[0040] Example 3

[0041] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 39wt%, 10wt%, 28wt%, 6wt%, 5wt% and 12wt%. Keep the mixture in a high-temperature furnace at 1500 °C for 1 h, and pour the obtained melt with a sulfur content < 1% and a viscosity < 200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 900 °C for 1.5 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 4.3 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.011 mg / L, flexural strength 104 MPa, bulk density 2.91 g·cm -3 , water absorption rate 0.068%.

[0042] Example 4

[0043] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 40wt%, 5wt%, 30wt%, 5wt%, 10wt% and 10wt%. Keep the mixture in a high-temperature furnace at 1450 °C for 1.5 h, and pour the obtained melt with a sulfur content < 1% and a viscosity < 200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 850 °C for 2 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 3.7 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.005 mg / L, flexural strength 100 MPa, bulk density 2.84 g·cm -3 , water absorption rate 0.074%.

[0044] Example 5

[0045] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to a mass ratio of 39wt%, 13wt%, 23wt%, 7wt%, 5wt% and 13wt%. Keep the mixture in a high-temperature furnace at 1400 °C for 1.5 h, and pour the obtained melt with a sulfur content < 1% and a viscosity < 200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 800 °C for 2.5 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 3.2 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.010 mg / L, flexural strength 91 MPa, bulk density 2.77 g·cm -3 , water absorption rate 0.083%.

[0046] Example 6

[0047] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to a mass ratio of 48wt%, 4wt%, 21wt%, 12wt%, 5wt% and 10wt%. Keep the mixture in a high-temperature furnace at 1350 °C for 2 h, and pour the obtained melt with a sulfur content < 1% and a viscosity < 200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 750 °C for 3 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 2.9 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.013 mg / L, flexural strength 86 MPa, bulk density 2.68 g·cm -3 , water absorption rate 0.094%.

[0048] Example 7

[0049] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 36wt%, 9wt%, 20wt%, 15wt%, 9wt% and 11wt%. Keep the mixture in a high-temperature furnace at 1300 °C for 2 h, and pour the obtained melt with a sulfur content <1% and a viscosity <200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 700 °C for 3 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 2.4 μm. The properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.017 mg / L, flexural strength 82 MPa, bulk density 2.60 g·cm -3 , water absorption rate 0.100 %.

[0050] Example 8

[0051] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 35wt%, 20wt%, 20wt%, 6wt%, 9wt% and 10wt%. Keep the mixture in a high-temperature furnace at 1320 °C for 2 h, and pour the obtained melt with a sulfur content <1% and a viscosity <200 Pa·s into a mold and anneal it to obtain the base glass. Finally, heat-treat the base glass at 730 °C for 2.5 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 2.5 μm. The properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.015 mg / L, flexural strength 89 MPa, bulk density 2.65 g·cm -3 , water absorption rate 0.092 %.

[0052] Example 9

[0053] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag, etc. and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 42wt%, 6wt%, 22wt%, 5wt%, 5wt% and 10wt%. Keep the mixture in a high-temperature furnace at 1370 °C for 2 h, and the obtained melt with a sulfur content < 1% and a viscosity < 200 Pa·s is poured into a mold and annealed to obtain the base glass. Finally, heat-treat the base glass at 820 °C for 2 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 3.4 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.008 mg / L, flexural strength 95 MPa, bulk density 2.73 g·cm -3 , water absorption rate 0.086 %.

[0054] Example 10

[0055] An embodiment of the present invention provides a method for preparing beryllium slag glass-ceramics, and the specific steps are as follows: First, dry beryllium slags such as beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag, etc. and solid waste auxiliary materials. Then, mix beryllium-silicon slag, beryllium-calcium slag, beryllium-alum slag, beryllium-iron slag, beryllium fluoride slag and solid waste auxiliary materials evenly according to the mass ratio of 38wt%, 0wt%, 32wt%, 5wt%, 15wt% and 10wt%. Keep the mixture in a high-temperature furnace at 1460 °C for 1 h, and the obtained melt with a sulfur content < 1% and a viscosity < 200 Pa·s is poured into a mold and annealed to obtain the base glass. Finally, heat-treat the base glass at 880 °C for 1.5 h and cool it to room temperature to obtain beryllium slag glass-ceramics with an average grain size of 3.9 μm. Properties of the beryllium slag glass-ceramics: beryllium leaching concentration 0.006 mg / L, flexural strength 102 MPa, bulk density 2.80 g·cm -3 , water absorption rate 0.071 %.

[0056] Although several embodiments of the present invention are given in this article, those skilled in the art should understand that the embodiments in this article can be changed without departing from the spirit of the present invention. The above embodiments are only exemplary and should not be used as a limitation of the scope of the rights of the present invention with the embodiments in this article.

Claims

1. A high performance beryllium slag glass-ceramics, characterized in that: The raw materials of the beryllium slag glass-ceramics include: 35wt%-55wt% of beryllium silicon slag, 0wt%-20wt% of beryllium calcium slag, 20wt%-40wt% of beryllium alum slag, 5wt%-15wt% of beryllium iron slag, 5wt%-15wt% of fluorine beryllium slag and 10wt%-20wt% of solid waste auxiliary materials, with a total amount of 100wt%; The preparation process is to melt and keep the material at a certain temperature to obtain a melt, cast the melt to obtain a basic glass and an alloy, and then anneal and heat treat the prepared basic glass to obtain the high-performance beryllium slag glass-ceramics. The properties of the beryllium slag glass-ceramics are: average grain size ≤5 μm, beryllium leaching concentration <0.02 mg / L, flexural strength ≥80 MPa, and volume density ≥2.60 g·cm -3 , water absorption rate ≤0.1%.

2. A method for preparing high-performance beryllium slag glass-ceramics according to claim 1, characterized in that: The following steps are involved: (1) Drying: Drying beryllium silicon slag, beryllium calcium slag, beryllium alum slag, beryllium iron slag, fluorine beryllium slag and solid waste auxiliary materials; (2) Mixing: The dried beryllium slag in step (1) is mixed evenly with the solid waste auxiliary material in a certain proportion to obtain a mixture; (3) Melting and casting: The mixed material obtained in step (2) is melted at a certain temperature and kept warm to obtain a melt, and the melt is cast and molded to obtain basic glass and alloy; the flue gas generated during the melting of the mixed material is discharged after dust removal and exhaust gas treatment to meet the standards, and the dust removal ash can be returned to the mixing process for use as an ingredient; (4) Annealing and heat treatment: The base glass obtained in step (3) is annealed and heat treated at a certain temperature to obtain beryllium slag glass-ceramics.

3. The method for preparing high-performance beryllium slag glass-ceramics according to claim 2, characterized in that: The beryllium slag described in step (1) is composed of one or more of the slag generated in the production process of beryllium and its compounds, dust collected by a dust collection (removal) device, and wastewater treatment sludge; wherein, the slag having an SiO2 content of ≥50wt% is beryllium silicon slag, the slag having a CaO content of ≥40wt% is beryllium calcium slag, the slag having an Al2O3 content of ≥20wt% is beryllium alum slag, the slag having an Fe2O3 content of ≥30wt% is beryllium iron slag, and the slag having an F content of ≥40wt% is fluorine beryllium slag; and the solid waste auxiliary material is solid waste or a solid waste mixture containing calcium, aluminum, and silicon.

4. The method for preparing high-performance beryllium slag glass-ceramics according to claim 2, characterized in that: In step (2), the mixture comprises 20wt%-40wt% SiO2, 18wt%-35wt% CaO, 5wt%-20wt% Al2O3, 2-10wt% Fe2O3 and 5wt%-15wt% F.

5. The method for preparing high-performance beryllium slag glass-ceramics according to claim 2, characterized in that: The melting temperature in step (3) is 1300-1600° C., the holding time is 0.5-2 h, the sulfur content in the melt after melting is less than 1%, and the melt viscosity is less than 200 Pa·s.

6. The method for preparing high-performance beryllium slag glass-ceramics according to claim 2, characterized in that: The heat treatment temperature in step (4) is 700-1000°C, and the heat treatment time is 0.5-3h.

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