A method for producing foamed glass using a hazardous waste vitrification product

Abstract

The application discloses a method for preparing foam glass by using hazardous waste melting vitrification products. The method comprises the following steps: uniformly mixing the hazardous waste melting vitrification products with a foaming agent and a foam stabilizer, and then performing forming, drying, high-temperature foaming and cooling treatment on the mixture to obtain the foam glass. The content of the foaming agent in the mixture is 1wt.%-4wt.%, the content of the foam stabilizer is 1wt.%-2wt.%, and the foaming temperature is 850 DEG C-940 DEG C, so that the hazardous waste melting vitrification products are efficiently foamed. The obtained foam glass product has the characteristics of heat insulation, light weight and high strength, is a new type of environment-friendly building material, and realizes high-value utilization of the hazardous waste melting vitrification products.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for resource utilization of hazardous waste molten vitrification products, in particular to a method for preparing foam glass from hazardous waste molten vitrification products, and belongs to the field of environmental protection technology. BACKGROUND

[0002] At present, the main hazardous waste harmless treatment technologies in China are cement solidification and stabilization treatment, chemical agent treatment and molten vitrification treatment. The cement solidification and stabilization treatment of hazardous waste has the advantages of simple equipment and operation, and relatively low solidification cost, but the capacity is increased seriously after cement solidification treatment, and the long-term solidification effect of heavy metals is poor; compared with cement solidification, the advantage of chemical agent treatment is high degree of heavy metal stabilization, less or no capacity increase, and many types of solidification agents, but the solidification cost of chemical agent is relatively high, and the solidification agent generally has strong selectivity, and the solidification effect of dioxin and dissolved salt is weak, and it is difficult to realize the synchronous solidification of multiple heavy metals; the molten vitrification technology has the characteristics of high temperature and high efficiency, and the effect of capacity and mass reduction is extremely obvious, and it has many advantages such as good harmless effect on harmful components and heavy metals in hazardous waste, and is an excellent way for hazardous waste harmless treatment, which has attracted more and more attention in recent years. However, after the molten vitrification of hazardous waste, there are still vitrification products, and there are few reports on the resource utilization of hazardous waste molten vitrification products.

[0003] Foam glass has the characteristics of high strength, small thermal conductivity, low water absorption, non-hygroscopic, good anti-freezing performance in humid environment, corrosion resistance, wide temperature range (-160~400°C) for use, etc., and is widely used in petroleum chemical industry, cold storage, fermentation and brewing industry, and is also a green, environmental protection and energy saving material, which is used as the inner and outer wall thermal insulation material of buildings. At present, flat glass, bottle and tank glass, boric acid glass of chemical industry, cathode ray tube glass and some fluorescent tube glass and other glass waste are often used as raw materials to produce foam glass by forming foam-like substances under the action of foaming agent. At present, the common types of foaming agent include thermal decomposition type foaming agent (such as calcium carbonate, sodium carbonate, etc.), oxidation-reduction reaction type foaming agent (carbon powder, SiC, starch, sucrose, etc.). The invention patent (publication number CN 113135657 A) discloses a method for preparing foam glass by melting and foaming hazardous waste molten vitrification products and auxiliary materials such as crushed glass, borax, limestone, waste graphite electrode at 950°C~1150°C.

[0004] In fact, any change in the chemical composition of the raw material of foamed glass will directly affect the viscosity and change the foaming temperature, resulting in the need to make corresponding adjustments to the type and amount of foaming agent. Even the same type of foaming agent has a great difference in the effect on the microstructure and performance of foamed glass, and the same glass powder will also exhibit different microstructure and performance under the action of different foaming agents. Therefore, in the production process of foamed glass, the regulation of the role of the foaming agent is the key. SUMMARY

[0005] In view of the problem that the resource utilization of hazardous waste melting vitrification products is not high, the present application aims to provide a method for preparing foamed glass from hazardous waste melting vitrification products, which uses hazardous waste melting vitrification products as raw materials, introduces a small amount of auxiliary materials, and simultaneously accurately regulates the heating rate and foaming temperature to create a micro zone liquid phase, improve the melt viscosity, realize the organic coupling of liquid phase formation and foaming agent decomposition and foaming, so as to realize the sufficient and uniform pores in the foamed glass. The present application can consume a large amount of hazardous waste melting vitrification products, turning waste into treasure, and the obtained foamed glass product has excellent performance.

[0006] The technical solutions specifically adopted by the present application are as follows:

[0007] The hazardous waste melting vitrification product is mixed with 1wt.%~4wt.% foaming agent and 1wt.%~2wt.% foaming stabilizer, and the mixture is uniformly mixed, formed, dried, heated to 850 o C~940 o C, foamed, and naturally cooled to obtain foamed glass.

[0008] As a preferred, the content of foaming agent in the mixture is 2wt.%~4wt.% and the content of foaming stabilizer is 1.5wt.%~2wt.%.

[0009] As a preferred, the foaming temperature is 900 o C~940 o C.

[0010] As a preferred, the foaming time is 40min~60min.

[0011] Compared with the prior art, the beneficial effects of the technical solutions of the present application are as follows:

[0012] The scheme for preparing the foamed glass from the hazardous waste molten vitrification product is based on a large number of experimental conclusions, and the inventors have found that the foaming agent dosage, the heating rate, the foaming temperature and the foaming time are key factors through a large number of studies on the influencing factors of the foamed glass preparation process. Therefore, the inventors have carried out systematic experimental research, and have summarized that the foaming agent dosage in the mixture is 1wt.% to 4wt.%, the heating rate is 10°C / min from room temperature to 800°C, the heating rate is 2°C / min from 800°C to the foaming temperature, the foaming temperature is 850 o C~940 o C, and the foaming time is 40min to 90min. By adjusting the foaming agent dosage and the foaming temperature, the micro zone liquid phase formation temperature in the mixture is coupled with the foaming agent decomposition and foaming temperature, so that the micro zone liquid phase is formed in the mixture, the melting temperature is reduced, the liquid phase viscosity is improved, and the micro zone liquid phase is formed under the action of the foaming agent. By further synergistically adjusting the heating rate and the foaming time, the bubble generation rate in the process is indirectly adjusted, so that the closed pores with uniform pore size and uniform distribution are formed, and the strength of the obtained foamed glass is fully ensured. At the same time, by synergistically adjusting the foaming agent dosage, the heating rate, the foaming temperature and the foaming time, the stability of the heavy metals in the hazardous waste molten vitrification product is further enhanced. Overall, the present application can obtain a foamed glass product with excellent performance by accurately adjusting the preparation process, and has a broad application prospect. Embodiment

[0013] The content of the present application will be further described in detail below in combination with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application. Embodiment 1

[0014] In this embodiment, the hazardous waste molten vitrification product, 4wt.% foaming agent and 2wt.% foaming stabilizer are uniformly mixed in the mixture, the mixture is formed, dried, foamed at a temperature of 940°C, and naturally cooled to obtain the foamed glass.

[0015] In this embodiment, the foaming agent is sodium carbonate, and the foaming stabilizer is trisodium phosphate.

[0016] In this embodiment, the heating rate is 10°C / min from room temperature to 800°C, and the heating rate is 2°C / min from 800°C to 940°C.

[0017] In this embodiment, the foaming time is 60min.

[0018] In this embodiment, the forming pressure is 6MPa.

[0019] In this embodiment, the glass content of the hazardous waste vitrification product is 95%.

[0020] The volume density of the foam glass obtained in this embodiment 1 is 500 kg / m 3 , the compressive strength is 1.93 MPa, the porosity is 74.10%, and the water absorption is 0.30%. Example 2

[0021] In this embodiment, the hazardous waste vitrification product is mixed with 4 wt.% foaming agent and 2 wt.% foam stabilizer in the mixture, the mixture is formed, dried, foamed at a temperature of 940°C, and naturally cooled to obtain the foam glass.

[0022] In this embodiment, the foaming agent is carbon powder, and the foam stabilizer is trisodium phosphate.

[0023] In this embodiment, the temperature rising rate is 10°C / min from room temperature to 800°C, and the temperature rising rate is 2°C / min from 800°C to 940°C.

[0024] In this embodiment, the foaming time is 40 min.

[0025] In this embodiment, the forming pressure is 6 MPa.

[0026] In this embodiment, the glass content of the hazardous waste vitrification product is 95%.

[0027] The volume density of the foam glass obtained in this embodiment 2 is 367 kg / m 3 , the compressive strength is 0.93 MPa, the porosity is 81.46%, and the water absorption is 0.34%. Example 3

[0028] In this embodiment, the hazardous waste vitrification product is mixed with 2 wt.% foaming agent and 2 wt.% foam stabilizer in the mixture, the mixture is formed, dried, foamed at a temperature of 850°C, and naturally cooled to obtain the foam glass.

[0029] In this embodiment, the foaming agent is sodium carbonate, and the foam stabilizer is trisodium phosphate.

[0030] In this embodiment, the temperature rising rate is 10°C / min from room temperature to 800°C, and the temperature rising rate is 2°C / min from 800°C to 850°C.

[0031] In this embodiment, the foaming time is 60 min.

[0032] In this embodiment, the forming pressure is 2 MPa.

[0033] In this embodiment, the glass content of the hazardous waste vitrification product is 85%.

[0034] The volume density of the foam glass obtained in this embodiment 4 is 662 kg / m 3 , the compressive strength is 2.40 MPa, the porosity is 62.58%, and the water absorption is 0.28%. Embodiment 4

[0035] In this embodiment, the hazardous waste vitrification product is mixed with 4 wt.% foaming agent and 2 wt.% foam stabilizer in the mixture, the mixture is formed, dried, foamed at a temperature of 900°C, and naturally cooled to obtain the foam glass.

[0036] In this embodiment, the foaming agent is sodium carbonate and the foam stabilizer is trisodium phosphate.

[0037] In this embodiment, the temperature rising rate is 10°C / min from room temperature to 800°C, and the temperature rising rate is 2°C / min from 800°C to 900°C.

[0038] In this embodiment, the foaming time is 90 min.

[0039] In this embodiment, the forming pressure is 4 MPa.

[0040] In this embodiment, the glass content of the hazardous waste vitrification product is 90%.

[0041] The volume density of the foam glass obtained in this embodiment 4 is 662 kg / m 3 , the compressive strength is 2.40 MPa, the porosity is 62.58%, and the water absorption is 0.28%. Embodiment 5

[0042] In this embodiment, the hazardous waste vitrification product is mixed with 3 wt.% foaming agent and 1.5 wt.% foam stabilizer in the mixture, the mixture is formed, dried, foamed at a temperature of 930°C, and naturally cooled to obtain the foam glass.

[0043] In this embodiment, the foaming agent is a mixture of sodium carbonate and carbon powder, and the foam stabilizer is trisodium phosphate.

[0044] In this embodiment, the temperature rising rate is 10°C / min from room temperature to 800°C, and the temperature rising rate is 2°C / min from 800°C to 900°C.

[0045] In this embodiment, the foaming time is 60 min.

[0046] In this embodiment, the forming pressure is 4 MPa.

[0047] In this embodiment, the glass content of the hazardous waste molten vitrification product is 90%.

[0048] The volume density of the foam glass obtained in this embodiment 5 is 459 kg / m 3 , the compressive strength is 1.87 MPa, the porosity is 76.12%, and the water absorption is 0.25%.

[0049] From the results of embodiments 1-5 above, it can be seen that the key to the technical solution of the present application is the content of the foaming agent in the mixture, which needs to be synergistically controlled in addition to the raw material components, the heating rate, the foaming temperature and the foaming time to ensure the organic coupling of the system liquid phase generation and the foaming process.

[0050] In order to further prove the necessity of the component quality ratio control and the foaming condition control of the above two aspects, the present application further provides several comparative examples. Comparative Example 1

[0051] In this comparative example, the hazardous waste molten vitrification product is mixed with 0.5wt.% foaming agent and 2wt.% stabilizing agent in the mixture, and the mixture is formed, dried, foamed at a temperature of 940°C, and naturally cooled to obtain the foam glass.

[0052] In this comparative example, the foaming agent is sodium carbonate and the stabilizing agent is trisodium phosphate.

[0053] In this comparative example, the heating rate from room temperature to 800°C is 10°C / min, and the heating rate from 800°C to 940°C is 2°C / min.

[0054] In this comparative example, the foaming time is 90 min.

[0055] In this comparative example, the forming pressure is 4 MPa.

[0056] In this comparative example, the glass content of the hazardous waste molten vitrification product is 90%.

[0057] The volume density of the foam glass obtained in this comparative example 1 is 1271 kg / m 3 , the compressive strength is 4.10 MPa, the porosity is 28.30%, and the water absorption is 0.21%. Comparative Example 2

[0058] In this comparative example, the hazardous waste molten vitrification product is mixed with 0.5wt.% foaming agent and 2wt.% stabilizing agent in the mixture, and the mixture is formed, dried, foamed at a temperature of 940°C, and naturally cooled to obtain the foam glass.

[0059] In this comparative example, the foaming agent is carbon powder and the stabilizing agent is trisodium phosphate.

[0060] In the present comparative example, the temperature rising rate from room temperature to 800°C is 10°C / min, and the temperature rising rate from 800°C to 940°C is 2°C / min.

[0061] In the present comparative example, the foaming time is 90 min.

[0062] In the present comparative example, the molding pressure is 4 MPa.

[0063] In the present comparative example, the glass content of the hazardous waste vitrification product is 90%.

[0064] The volume density of the foam glass obtained in Comparative Example 2 is 1100 kg / m 3 , the compressive strength is 1.10 MPa, the porosity is 30.52%, and the water absorption is 2.21%. Comparative Example 3

[0065] In the present comparative example, the hazardous waste vitrification product is mixed with 4 wt.% foaming agent and 2 wt.% foam stabilizer in the mixture, and the mixture is molded, dried, foamed at a temperature of 840°C, and naturally cooled to obtain the foam glass.

[0066] In the present comparative example, the foaming agent is sodium carbonate, and the foam stabilizer is trisodium phosphate.

[0067] In the present comparative example, the temperature rising rate from room temperature to 800°C is 15°C / min, and the temperature rising rate from 800°C to 940°C is 5°C / min.

[0068] In the present comparative example, the foaming time is 60 min.

[0069] In the present comparative example, the molding pressure is 4 MPa.

[0070] In the present comparative example, the glass content of the hazardous waste vitrification product is 90%.

[0071] The volume density of the foam glass obtained in Comparative Example 3 is 871 kg / m 3 , the compressive strength is 3.10 MPa, the porosity is 22.09%, and the water absorption is 1.29%. Comparative Example 4

[0072] In the present comparative example, the hazardous waste vitrification product is mixed with 4 wt.% foaming agent and 2 wt.% foam stabilizer in the mixture, and the mixture is molded, dried, foamed at a temperature of 840°C, and naturally cooled to obtain the foam glass.

[0073] In the present comparative example, the foaming agent is a mixture of sodium carbonate and carbon powder, and the foam stabilizer is trisodium phosphate.

[0074] In the present comparative example, the temperature rising rate from room temperature to 800°C is 10°C / min, and the temperature rising rate from 800°C to 840°C is 2°C / min.

[0075] In the present comparative example, the foaming time is 90 min.

[0076] In the present comparative example, the molding pressure is 4 MPa.

[0077] In the present comparative example, the glass content of the hazardous waste vitrification product is 95%.

[0078] The volume density of the foam glass obtained in the present comparative example 4 is 1321 kg / m 3 , the compressive strength is 3.32 MPa, the porosity is 18.12%, and the water absorption is 3.01%. Comparative Example 5

[0079] In the present comparative example, the hazardous waste vitrification product is mixed with 4 wt.% foaming agent and 2 wt.% foam stabilizer in the mixture, the mixture is molded, dried, foamed at a temperature of 940°C, and naturally cooled to obtain the foam glass.

[0080] In the present comparative example, the foaming agent is sodium carbonate, and the foam stabilizer is trisodium phosphate.

[0081] In the present comparative example, the temperature rising rate from room temperature to 800°C is 10°C / min, and the temperature rising rate from 800°C to 940°C is 2°C / min.

[0082] In the present comparative example, the foaming time is 30 min.

[0083] In the present comparative example, the molding pressure is 4 MPa.

[0084] In the present comparative example, the glass content of the hazardous waste vitrification product is 90%.

[0085] The volume density of the foam glass obtained in the present comparative example 5 is 1117 kg / m 3 , the compressive strength is 0.92 MPa, the porosity is 10.98%, and the water absorption is 1.33%.

[0086] It is apparent for a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application, and thus the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being defined by the appended claims rather than the above description, and it is intended to embrace all changes and modifications falling within the meaning and scope of the equivalent elements of the claims.

[0087] Furthermore, it should be understood that although the description is made according to the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and the person skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be combined appropriately to form other embodiments that can be understood by the person skilled in the art.

Claims

1. A method for making foam glass from a hazardous waste vitrification product, characterized by: The hazardous waste molten vitrification product is mixed with 2wt.%-4wt.% foaming agent and 1.5wt.%-2wt.% foam stabilizer, the mixture is formed, dried, heated to a temperature of 850°C-940°C for foaming, and after natural cooling, the foam glass is obtained; The foaming agent is one or both of sodium carbonate and carbon powder, and the foam stabilizer is trisodium phosphate; The heating rate is 10°C / min from room temperature to 800°C and 2°C / min from 800°C to the foaming temperature; The forming pressure is 2MPa-6MPa.

2. The method of claim 1, wherein the method is characterized by: The foaming temperature is 900°C-940°C.

3. The method of claim 1, wherein the method is characterized by: The glass content in the hazardous waste molten vitrification product is greater than 85%.