A sludge brick based on sewage treatment plant sludge and its preparation method

Abstract

This invention proposes a sludge brick based on sewage treatment plant sludge and its preparation method, belonging to the field of building materials technology. The sludge brick, by weight, comprises the following raw material components: 50-70 parts sewage sludge, 8-12 parts reinforcing agent, 8-10 parts ceramic fragments, 6-8 parts heavy metal ion scavenging agent, 3-4 parts deodorizing agent, and 9-12 parts water. This invention utilizes domestic sewage sludge to prepare sludge bricks, reducing sludge disposal problems, avoiding the impact of domestic sewage sludge on the environment and human health, and achieving resource recycling. Furthermore, the preparation process defined in this invention reduces the generation and emission of waste gas, ensures that wastewater meets discharge standards, reduces environmental impact, and the prepared sludge bricks possess excellent mechanical properties, expanding their application prospects in building materials.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and in particular relates to a sludge brick based on sewage treatment plant sludge and its preparation method. Background Technology

[0002] Currently, the treatment and disposal of domestic sewage sludge faces several challenges. On the one hand, the complex and variable composition of domestic sewage sludge makes it difficult to treat and dispose of it uniformly. On the other hand, domestic sewage sludge contains large amounts of organic matter, heavy metal ions, and pathogens, which can pose a threat to the environment and human health if not properly treated. Therefore, scientific and reasonable methods are needed to treat and dispose of domestic sewage sludge to reduce its impact on the environment and human health.

[0003] While existing technologies exist for preparing silt bricks using sludge and conventional building materials, the resulting silt bricks exhibit unsatisfactory mechanical properties and poor brick-forming ability, such as low flexural and compressive strength. Furthermore, research on treating domestic sewage sludge to produce silt bricks is still scarce. Given the national encouragement for the vigorous development of a circular economy and environmental protection and energy conservation, the utilization of domestic sewage sludge is an urgent issue that needs to be addressed.

[0004] Therefore, there is an urgent need to provide a feasible preparation method that can produce a domestic sewage sludge brick with excellent mechanical properties. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a sludge brick based on sewage treatment plant sludge and its preparation method. Through the interaction of the various raw material components defined in this invention, domestic sewage sludge is utilized, transforming waste into a valuable resource, while simultaneously improving the mechanical properties of the prepared sludge brick and expanding its application prospects in building materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions of the present invention:

[0008] A sludge brick based on sewage treatment plant sludge, comprising the following raw material components by weight:

[0009] The ingredients are: 50-70 parts domestic sewage sludge, 8-12 parts enhancer, 8-10 parts ceramic fragments, 6-8 parts heavy metal ion capture agent, 3-4 parts deodorizer, and 9-12 parts water.

[0010] Preferably, the reinforcing agent is one or both of hydroxymethyl cellulose and montmorillonite.

[0011] Furthermore, the reinforcing agent is composed of hydroxymethyl cellulose and montmorillonite in a mass ratio of 1:1.

[0012] Beneficial effects: This invention specifies that hydroxymethyl cellulose and montmorillonite are used as reinforcing agents in a mass ratio of 1:1. Through the interaction between the two, shrinkage during the drying process is reduced, and bending deformation during the drying process is avoided. At the same time, the flexural strength and compressive strength of the prepared silt bricks are also improved.

[0013] Preferably, the particle size of the ceramic fragments is 4-7 mm.

[0014] Beneficial effects: This invention, through the interaction of limited ceramic fragments and reinforcing agents, synergistically improves the mechanical properties of the final prepared silt bricks, such as flexural strength and compressive strength.

[0015] Preferably, the heavy metal ion scavenging agent is composed of 1-2 parts sodium silicate, 1-3 parts sodium dithiocarbamate, 0.6-1.5 parts sodium aluminate, and 1.2-1.8 parts sodium hydrosulfide by weight.

[0016] Beneficial Effects: The heavy metal ion scavenging agent specified in this invention has a strong binding affinity for heavy metal ions. It can react with heavy metal ions at room temperature and within a wide pH range, thereby achieving the purpose of removing heavy metal ions from water. In other words, the components specified in this invention work synergistically to effectively remove heavy metal ions from sewage sludge without affecting the compressive and flexural strength of the sludge bricks, reducing the harm of sludge bricks to human health and thus expanding the application prospects of sludge bricks in building materials.

[0017] Preferably, the deodorizing agent is caustic soda flakes.

[0018] Beneficial effects: Sodium hydroxide is an alkaline substance that can neutralize acidic substances in sludge, thereby achieving the purpose of deodorizing and removing odors.

[0019] The second technical solution of the present invention:

[0020] A method for preparing sludge bricks based on sewage treatment plant sludge includes the following steps:

[0021] (1) Weigh the above raw material components according to the weight proportions and set aside;

[0022] (2) Add the heavy metal ion capture agent and deodorant to the sewage sludge and let it stand for reaction, i.e. harmless pretreatment, and then filter, dry, crush and sieve to obtain sludge particles.

[0023] (3) The sludge particles are mixed with the remaining raw material components, stirred evenly, pressed into brick blanks, and then sintered to obtain the sludge brick based on sewage treatment plant sludge.

[0024] Preferably, the static reaction conditions in step (2) are: harmless treatment at room temperature for 4-6 hours.

[0025] Preferably, the drying temperature in step (2) is 60-90℃ and the drying time is 13-16h.

[0026] Preferably, the sieving in step (2) is sieved through a 60-120 mesh sieve.

[0027] Preferably, the working pressure during the pressing process in step (3) is 5-7 MPa.

[0028] Preferably, the sintering temperature in step (3) is 600-900℃ and the sintering time is 1-2h.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] (1) The preparation method of the present invention is simple and easy to implement, and is suitable for industrial production;

[0031] (2) The reinforcing agent and ceramic fragments specified in this invention work synergistically to improve the mechanical properties of silt bricks;

[0032] (3) This invention defines a novel heavy metal ion scavenging agent that, under ambient temperature and a wide pH range, reacts with Cu in sewage sludge. 2+ Cd 2+ Hg 2+ Pb 2+ Mn 2+ Cr 3+ Various heavy metal ions undergo chemical reactions and rapidly generate insoluble, low-water-content, easily filtered flocculent precipitates within a short time, thereby achieving the effect of removing heavy metal ions from sewage sludge. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] All raw materials used in the embodiments of this invention were obtained through commercial purchase.

[0039] Unless otherwise specified, the term "parts" used in the embodiments of this invention refers to "parts by weight".

[0040] The technical solution of the present invention will be further illustrated by the following embodiments.

[0041] Example 1

[0042] A sludge brick based on sewage treatment plant sludge, comprising the following raw material components:

[0043] The mixture consists of 50 parts domestic sewage sludge, 8 parts reinforcing agent, 8 parts ceramic fragments, 6 parts heavy metal ion capture agent, 3 parts caustic soda flakes, and 9 parts water.

[0044] The reinforcing agent is composed of hydroxymethyl cellulose and montmorillonite in a mass ratio of 1:1.

[0045] The particle size of the ceramic fragments is 4mm;

[0046] The heavy metal ion scavenger consists of 1 part sodium silicate, 1 part sodium dithiocarbamate, 0.6 parts sodium aluminate, and 1.2 parts sodium hydrosulfide.

[0047] A method for preparing sludge bricks based on sewage treatment plant sludge includes the following steps:

[0048] (1) Weigh the above raw material components according to the weight proportions and set aside;

[0049] (2) Add heavy metal ion capture agent and deodorant to domestic sewage sludge and let it stand for 4 hours for harmless pretreatment, then filter it, dry it at 60°C for 13 hours, crush it, and pass it through a 60-mesh sieve to obtain sludge particles.

[0050] (3) Mix the sludge particles with the remaining raw material components, stir evenly, press into brick blanks under a working pressure of 5MPa, and then sinter at 600℃ for 1h to obtain sludge bricks based on sewage treatment plant sludge.

[0051] Example 2

[0052] The difference from Example 1 is that a sludge brick based on sewage treatment plant sludge includes the following raw material components:

[0053] The mixture consists of 60 parts domestic sewage sludge, 9 parts enhancing agent, 9 parts ceramic fragments, 7 parts heavy metal ion capture agent, 3 parts deodorizer, and 11 parts water.

[0054] Other conditions are the same as in Example 1.

[0055] Example 3

[0056] The difference from Example 1 is that a sludge brick based on sewage treatment plant sludge includes the following raw material components:

[0057] The mixture consists of 70 parts domestic sewage sludge, 12 parts reinforcing agent, 10 parts ceramic fragments, 8 parts heavy metal ion capture agent, 4 parts deodorizer, and 12 parts water.

[0058] Other conditions are the same as in Example 1.

[0059] Example 4

[0060] The difference from Example 1 is that,

[0061] In a method for preparing sludge bricks based on sewage treatment plant sludge, step (2) involves drying at a temperature of 80°C for 14 hours.

[0062] Other conditions are the same as in Example 1.

[0063] Example 5

[0064] The difference from Example 1 is that,

[0065] In a method for preparing sludge bricks based on sewage treatment plant sludge, the working pressure in step (3) of the pressing process is 6 MPa.

[0066] Other conditions are the same as in Example 1.

[0067] Example 6

[0068] The difference from Example 1 is that,

[0069] In a method for preparing sludge bricks based on sewage treatment plant sludge, the sintering temperature in step (3) is 700℃.

[0070] Other conditions are the same as in Example 1.

[0071] Example 7

[0072] The difference from Example 1 is that,

[0073] In a method for preparing sludge bricks based on sewage treatment plant sludge, the sintering temperature in step (3) is 900℃.

[0074] Other conditions are the same as in Example 1.

[0075] Comparative Example 1

[0076] The difference from Example 1 is that no ceramic slag is added, while the other conditions are the same as in Example 1.

[0077] Comparative Example 2

[0078] The difference from Example 1 is that no reinforcing agent is added, while the other conditions are the same as in Example 1.

[0079] Comparative Example 3

[0080] The difference from Example 1 is that the drying temperature in step (2) of the method for preparing sludge bricks based on sewage treatment plant sludge is 30°C, and the other conditions are the same as in Example 1.

[0081] Comparative Example 4

[0082] The difference from Example 1 is that the drying temperature in step (2) of the method for preparing sludge bricks based on sewage treatment plant sludge is 120°C, and the other conditions are the same as in Example 1.

[0083] Comparative Example 5

[0084] The difference from Example 1 is that the sintering temperature in step (3) of the method for preparing sludge bricks based on sewage treatment plant sludge is 500°C, and the other conditions are the same as in Example 1.

[0085] Comparative Example 6

[0086] The difference from Example 1 is that the sintering temperature in step (3) of the method for preparing sludge bricks based on sewage treatment plant sludge is 1000℃, and the other conditions are the same as in Example 1.

[0087] Effect verification

[0088] I. The removal effect of heavy metal ions in the sludge bricks based on sewage treatment plant sludge prepared in Examples 1-3 of the present invention was tested, and the details are shown in Table 1.

[0089] Table 1

[0090]

[0091] Conclusion: The heavy metal ion scavenger defined in this invention can effectively remove Cu from domestic sewage sludge. 2+ Cd 2+ Hg 2+ Pb 2+ Mn 2+ Cr 3+ The overall removal rate of heavy metal ions can reach 98-99.92%, which is a very significant removal effect.

[0092] II. The mechanical properties of the sludge bricks based on sewage treatment plant sludge prepared in Examples 1-7 and Comparative Examples 1-6 were tested, specifically as follows:

[0093] Referring to the compressive strength and flexural strength tests in GB / T2542-2012 "Test Methods for Masonry Bricks", the sludge brick samples based on sewage treatment plant sludge prepared in Examples 1-7 and Comparative Examples 1-6 were made into specimens of specified dimensions. The specimens were then tested, and the compressive strength and flexural strength were calculated. See Table 2 for details.

[0094] Table 2

[0095] Compressive strength / MPa Flexural strength / MPa Example 1 38.9 9.7 Example 2 39.7 9.6 Example 3 39.2 9.9 Example 4 39.6 10 Example 5 38.2 9.8 Example 6 38.9 9.5 Example 7 39.0 9.3 Comparative Example 1 15.9 5.3 Comparative Example 2 12.6 5.2 Comparative Example 3 32.5 8.6 Comparative Example 4 33.9 8.5 Comparative Example 5 31.7 8.0 Comparative Example 6 32.0 8.3

[0096] Conclusion: Based on the mechanical property data in Table 2, it can be seen that the reinforcing agent and ceramic fragments specified in this invention synergistically improve the compressive and flexural strength of the prepared silt bricks. For example, the silt brick prepared in Example 1 exhibits a compressive strength of 38.9 MPa and a flexural strength of 9.7 MPa; while the highest compressive strength without the addition of the reinforcing agent and ceramic fragments is only 15.9 MPa, and the highest flexural strength is only 5.3 MPa. This demonstrates that the interaction between the raw material components specified in this invention can significantly improve the mechanical properties of silt bricks. Furthermore, by pretreating the silt to render it harmless, the safe use of the silt bricks can be ensured, and waste resources can be transformed into valuable resources through rational utilization.

[0097] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A sludge brick based on sewage treatment plant sludge, characterized in that, By weight, it includes the following raw material components: 50-70 parts of domestic sewage sludge, 8-12 parts of enhancer, 8-10 parts of ceramic fragments, 6-8 parts of heavy metal ion capture agent, 3-4 parts of deodorizer, and 9-12 parts of water; The heavy metal ion scavenging agent, by weight, is composed of 1-2 parts sodium silicate, 1-3 parts sodium dithiocarbamate, 0.6-1.5 parts sodium aluminate, and 1.2-1.8 parts sodium hydrosulfide. The reinforcing agent is composed of hydroxymethyl cellulose and montmorillonite in a mass ratio of 1:1; The method for preparing sludge bricks based on sewage treatment plant sludge includes the following steps: (1) Weigh the raw material components according to the weight proportions and set aside; (2) Add the heavy metal ion capture agent and deodorant to the domestic sewage sludge and let it stand to react, and then filter, dry, crush and sieve to obtain sludge particles; (3) The sludge particles are mixed with the remaining raw material components, stirred, pressed into brick blanks, and then sintered to obtain the sludge brick based on sewage treatment plant sludge.

2. The sludge brick based on sewage treatment plant sludge according to claim 1, characterized in that, The deodorant is caustic soda flakes.

3. A method for preparing sludge bricks based on sewage treatment plant sludge, characterized in that, Includes the following steps: (1) Weigh the raw material components according to any one of claims 1-2 according to the weight parts for later use; (2) Add the heavy metal ion capture agent and deodorant to the domestic sewage sludge and let it stand to react, and then filter, dry, crush and sieve to obtain sludge particles; (3) The sludge particles are mixed with the remaining raw material components, stirred, pressed into brick blanks, and then sintered to obtain the sludge brick based on sewage treatment plant sludge.

4. The method for preparing sludge bricks based on sewage treatment plant sludge according to claim 3, characterized in that, The drying temperature in step (2) is 60-90℃ and the drying time is 13-16h.

5. The method for preparing sludge bricks based on sewage treatment plant sludge according to claim 3, characterized in that, The sieving in step (2) is sieving through a 60-120 mesh sieve.

6. The method for preparing sludge bricks based on sewage treatment plant sludge according to claim 3, characterized in that, The working pressure during the pressing process in step (3) is 5-7 MPa.

7. The method for preparing sludge bricks based on sewage treatment plant sludge according to claim 3, characterized in that, The sintering temperature in step (3) is 600-900℃ and the sintering time is 1-2h.

Images