Printing and dyeing sludge building material resourceful treatment method based on baking-free low-temperature process

Abstract

The invention relates to a printing and dyeing sludge building material resourceful treatment method based on an unfired low-temperature process, and belongs to the technical field of sludge resourceful treatment. In order to solve the problem that an existing printing and dyeing sludge treatment method cannot give consideration to safety, environmental protection and resourceful treatment, the invention provides a printing and dyeing sludge building material resourceful treatment method based on an unfired low-temperature process, and a printing and dyeing sludge material subjected to resourceful treatment is obtained through pre-dehydration, crushing and screening treatment, harmless treatment and drying treatment. According to the characteristics of the printing and dyeing sludge, organic pollutants and heavy metal ions are subjected to innocent treatment through a Fenton reaction system and alkalization treatment, and secondary pollution is avoided; a high-temperature and high-pressure process is not needed, and building recycling treatment of the printing and dyeing sludge can be completed under a normal-temperature condition. The printing and dyeing sludge powder subjected to resource treatment can be directly used as an admixture to be applied to preparation of cement-based building material products, so that the production cost of the building material products can be reduced, and the carbon footprint of the building material products can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge resource treatment, and in particular relates to a method for resource treatment of printing and dyeing sludge building materials based on a non-burning low-temperature process. Background Art

[0002] Printing and dyeing sludge comes from the production process of textile printing and dyeing industry. It has the characteristics of high water content, complex composition, and contains a large number of non-degradable organic compounds from printing and dyeing dyes. Due to these characteristics, printing and dyeing sludge is difficult to be used as a resource. At present, the treatment of printing and dyeing sludge mainly focuses on how to dehydrate it efficiently and reduce its accumulation volume to facilitate storage, transfer and transportation.

[0003] At present, the disposal methods of printing and dyeing sludge are still mainly traditional landfill and incineration. Since printing and dyeing sludge itself contains a large amount of organic matter and even heavy metal ions, these two disposal methods will inevitably cause environmental pollution. Specifically, the disposal of printing and dyeing sludge by landfill is prone to cause soil pollution and groundwater pollution, which poses a huge safety hazard to the living environment of animals and plants around the landfill area, and the probability of causing secondary pollution is extremely high. The disposal of printing and dyeing sludge by incineration, first of all, due to the high water content, the incineration process consumes a huge amount of energy, and also emits a large amount of carbon dioxide and other waste gases, causing atmospheric environmental pollution; at the same time, since printing and dyeing sludge contains a large amount of organic matter, such as polycyclic aromatic compounds, toxic and harmful substances such as dioxins, nitrogen oxides, sulfur dioxide, fly ash, etc. will be produced during the incineration process, which will have a serious impact on the environment and human health.

[0004] Based on the existing literature, there is no effective way to realize the resource utilization of printing and dyeing sludge. In fact, the dried printing and dyeing sludge can be classified as industrial solid waste. Analysis of its components shows that the printing and dyeing sludge contains relatively rich components such as aluminum oxide, silicon dioxide and calcium oxide. After proper disposal, it can be used as an admixture for building materials, which is an effective way to realize the resource utilization of printing and dyeing sludge. However, the prerequisite for the implementation of this method is to be able to pre-treat the printing and dyeing sludge safely and effectively. In this process, it is necessary to remove organic matter and ensure that no secondary pollution is caused, while taking into account the low-carbon green disposal policy.

[0005] Therefore, how to achieve resource-based treatment of printing and dyeing sludge while ensuring safety and environmental protection remains an urgent problem to be solved in this field. Summary of the invention

[0006] In order to solve the problem that the existing printing and dyeing sludge treatment method cannot take into account both safety, environmental protection and resource recovery, the present invention provides a printing and dyeing sludge building material resource recovery method based on a non-firing low-temperature process.

[0007] The technical solution of the present invention:

[0008] The method for recycling printing and dyeing sludge building materials based on the non-burning low-temperature process includes the following steps:

[0009] Step 1: Pre-dehydration treatment:

[0010] The water content of the dyeing sludge in a water-saturated state is reduced to below the saturated water content by using the traditional physical industrial sludge dehydration method to obtain the pre-dehydrated dyeing sludge;

[0011] Step 2: Crushing and screening:

[0012] The pre-dehydrated printing and dyeing sludge obtained in step 1 is mechanically crushed to obtain fragments; the obtained fragments are further refined and crushed while being dried to obtain particles with a smaller particle size, the obtained particles are screened, the particles that have not passed the screening are returned for further crushing, and the particles that have passed the screening are the refined printing and dyeing sludge;

[0013] Step 3: Harmless treatment:

[0014] Decomposing the residual organic components in the fine printing and dyeing sludge obtained in step 2 by Fenton reaction to obtain deorganized printing and dyeing sludge; alkalizing the obtained deorganized printing and dyeing sludge to obtain alkalized sludge;

[0015] Step 4: Drying:

[0016] The alkalized sludge obtained in step three is subjected to solid-liquid separation and drying treatment to obtain printing and dyeing sludge powder.

[0017] Furthermore, the traditional physical industrial sludge dehydration method in step 1 includes plate filter press or centrifugal dehydration; the moisture content of the pre-dehydrated printing and dyeing sludge is 55-75%.

[0018] Furthermore, the mechanical crushing in step 2 is to transfer the pre-dehydrated printing and dyeing sludge to an auger transmission device for crushing, and the particle size of the obtained fragments is 0.5 to 2.0 cm.

[0019] Furthermore, the fine crushing in step 2 is to transfer the obtained pieces to a steam drying device equipped with spiral auger blades, introduce hot steam into the device to dry the pieces, and at the same time rotate the auger to further crush the pieces.

[0020] Furthermore, the screening in step 2 is performed using a graded vibrating screen, and two graded screens with mesh sizes of 19 mm and 0.3 mm are selected for fineness control. Particles that cannot pass through the 19 mm sieve are returned for mechanical crushing, and particles that pass through the 19 mm sieve but cannot pass through the 0.3 mm sieve are returned for fine crushing.

[0021] Furthermore, the Fenton reaction in step three is to place the refined printing and dyeing sludge obtained in step two and water in a Fenton reaction device, stir to obtain printing and dyeing sludge slurry, add an inorganic acid solution to adjust the pH of the printing and dyeing sludge slurry to 2.5-3.5, add ferrous sulfate and hydrogen peroxide, and continue stirring to ensure that the Fenton reaction is fully carried out.

[0022] Furthermore, the mass ratio of the refined printing and dyeing sludge, water, ferrous sulfate and hydrogen peroxide is 7-12:7-10:0.20-0.35:0.80-1.20; the inorganic acid solution is sulfuric acid, and the continuous stirring time is 0.5-1.5 hours.

[0023] Furthermore, the alkalization treatment in step 3 is to add an alkaline compound to the deorganized printing and dyeing slurry and fully stir it for 15 to 45 minutes.

[0024] Furthermore, the alkaline compound is quicklime, industrial caustic soda, slaked lime or soda ash, and the amount of the alkaline compound added is calculated based on a mass ratio of refined printing and dyeing sludge to the alkaline compound of 10:1.0-2.0.

[0025] Furthermore, the solid-liquid separation in step 4 is carried out using a centrifugal dehydration device.

[0026] Beneficial effects of the present invention:

[0027] The non-firing low-temperature process provided by the present invention is a green treatment method developed for the characteristics of printing and dyeing sludge with high moisture content, organic pollutants and heavy metal ions. The Fenton reaction system and alkalization treatment are respectively aimed at the organic pollutants and heavy metal ions that may be introduced into the dye, ensuring that the printing and dyeing sludge will not cause secondary pollution during the resource utilization process. The resource treatment process of printing and dyeing sludge of the present invention does not require high temperature, high pressure and high energy consumption processes, and the construction resource disposal of printing and dyeing sludge can be completed under normal temperature conditions.

[0028] The printing and dyeing sludge obtained by the building materials resource disposal method of the present invention can be directly used as an admixture in the preparation of cement-based building materials without further processing. It can partially replace 20-50% of ordinary Portland cement while meeting the requirements of safety and use, directly reducing the amount of cement, which can not only reduce the production cost of building materials, but also reduce the carbon footprint of building materials, thereby promoting the greening process of the civil engineering materials industry.

[0029] The present invention provides an effective way for the resource utilization of printing and dyeing sludge and similar sludges. Based on the disposal method of the present invention, a broad space can be provided for the resource utilization of printing and dyeing sludge: the annual cement consumption in the Yangtze River Delta region where the textile printing and dyeing industry in my country is relatively developed is about 250 million tons. The potential amount of cement replaced by printing and dyeing sludge through building material resource disposal can reach 25-75 million tons / year; at the same time, the energy consumption saved by reducing the production of this part of cement can reach 1.7 billion kWh / year, and the average carbon dioxide emissions can be reduced by 50 million tons / year.

[0030] The present invention provides a treatment method for the main hazards of printing and dyeing sludge, and designs a disposal process suitable for continuous production based on actual industrial production; at the same time, the present invention fully considers the material characteristics of mineral admixtures in cement-based building materials and adds a process for screening and controlling the particle size of printing and dyeing sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a real photo of the printing and dyeing sludge powder obtained by the resource processing method of the printing and dyeing sludge building materials of the present invention;

[0032] Figure 2 This is a real photo of a sludge brick prepared using the printing and dyeing sludge powder prepared in Example 1 as raw material;

[0033] Figure 3 This is a physical photo of a small trial production sample of building materials prepared using the printing and dyeing sludge powder obtained in the present invention as raw material;

[0034] Figure 4 The present invention is a photo of a pilot production specimen of a building material prepared using the printing and dyeing sludge powder obtained in the present invention as a raw material. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0036] Example 1

[0037] This embodiment provides a method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning, which specifically includes the following steps:

[0038] Step 1: Pre-dehydration treatment:

[0039] The printing and dyeing sludge in a water-saturated state is added to a plate filter press for physical dehydration. During the filtration process, a 25-mesh sponge rubber outer filter cloth and a 100-mesh textile filter cloth are selected for filter pressing and dehydration of the printing and dyeing sludge. After the physical dehydration process, the moisture content of the printing and dyeing sludge is reduced to 70%, and a printing and dyeing sludge cake is obtained, namely, pre-dehydrated printing and dyeing sludge.

[0040] Step 2: Crushing and screening:

[0041] The printing and dyeing sludge cake obtained in step one is conveyed to an auger transmission device for cake crushing, and the printing and dyeing sludge cake is crushed into printing and dyeing sludge fragments with a particle size of 0.5 to 2.0 cm; the obtained fragments are transferred to a steam drying device equipped with spiral auger blades through a conveyor belt, hot steam is introduced into the equipment to dry the printing and dyeing sludge fragments, and at the same time, the auger is slowly rotated to further refine and crush the printing and dyeing sludge fragments to obtain particles with smaller particle size.

[0042] Start the grading vibrating screen to screen the obtained particles, and select two grading screens with mesh sizes of 19mm and 0.3mm to control the particle fineness. Large particles that cannot pass through the 19mm sieve are returned to the auger transmission equipment for further mechanical crushing, and particles that pass through the 19mm sieve but cannot pass through the 0.3mm sieve are returned to the steam drying equipment equipped with spiral auger blades for further refinement and crushing. The sludge particles that pass through the 0.3mm sieve are collected and used as refined printing and dyeing sludge.

[0043] Step 3: Harmless treatment:

[0044] The Fenton reaction is used to decompose the residual organic components in the refined printing and dyeing sludge obtained in step 2. Specifically, 10 parts by mass of the refined printing and dyeing sludge are transferred to a Fenton reaction tank, 10 parts by mass of water and 0.25 parts by mass of ferrous sulfate are added, and the mechanical stirring device of the equipment is turned on to form a printing and dyeing sludge slurry with a solid-liquid ratio of 1:1. Sulfuric acid is used to adjust the pH of the printing and dyeing sludge slurry to 3.5, and then 1 part by mass of hydrogen peroxide is added. Stirring is continued for 1 hour to ensure that the chemical treatment is fully carried out to obtain a deorganized printing and dyeing sludge.

[0045] The obtained deorganized printing and dyeing sludge was pumped to an alkalization treatment tank, 1.2 parts by weight of quicklime was added and stirred for 25 minutes to form an alkalized sludge with stable alkalinity;

[0046] Step 4: Alkalinization and drying treatment:

[0047] The alkalized sludge obtained in step three is pumped to a centrifugal dehydration device for solid-liquid separation to obtain alkalized printing and dyeing sludge with a certain water content, and then the water-containing alkalized printing and dyeing sludge is conveyed to a blast drying device for drying to obtain dry printing and dyeing sludge powder, that is, printing and dyeing sludge building material resource disposal material.

[0048] Example 2

[0049] This embodiment provides a method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning, which specifically includes the following steps:

[0050] Step 1: Pre-dehydration treatment:

[0051] The printing and dyeing sludge in a water-saturated state is added to a plate filter press for physical dehydration. During the filtration process, a 25-mesh sponge rubber outer filter cloth and a 100-mesh textile filter cloth are selected for filter pressing and dehydration of the printing and dyeing sludge. After the physical dehydration process, the moisture content of the printing and dyeing sludge is reduced to 60%, and a printing and dyeing sludge cake is obtained, namely, pre-dehydrated printing and dyeing sludge.

[0052] Step 2: Crushing and screening:

[0053] The printing and dyeing sludge cake obtained in step one is conveyed to an auger transmission device for cake crushing, and the printing and dyeing sludge cake is crushed into printing and dyeing sludge fragments with a particle size of 0.5 to 2.0 cm; the obtained fragments are transferred to a steam drying device equipped with spiral auger blades through a conveyor belt, hot steam is introduced into the equipment to dry the printing and dyeing sludge fragments, and at the same time, the auger is slowly rotated to further refine and crush the printing and dyeing sludge fragments to obtain particles with smaller particle size.

[0054] Start the grading vibrating screen to screen the obtained particles, and select two grading screens with mesh sizes of 19mm and 0.3mm to control the particle fineness. Large particles that cannot pass through the 19mm sieve are returned to the auger transmission equipment for further mechanical crushing, and particles that pass through the 19mm sieve but cannot pass through the 0.3mm sieve are returned to the steam drying equipment equipped with spiral auger blades for further refinement and crushing. The sludge particles that pass through the 0.3mm sieve are collected and used as refined printing and dyeing sludge.

[0055] Step 3: Harmless treatment:

[0056] The Fenton reaction is used to decompose the residual organic components in the refined printing and dyeing sludge obtained in step 2. Specifically, 7 parts by mass of the refined printing and dyeing sludge are transferred to a Fenton reaction tank, 10 parts by mass of water and 0.20 parts by mass of ferrous sulfate are added, and the mechanical stirring device of the equipment is turned on to form a printing and dyeing sludge slurry with a solid-liquid ratio of 0.7:1. Sulfuric acid is used to adjust the pH of the printing and dyeing sludge slurry to 2.8, and then 0.9 parts by mass of hydrogen peroxide are added. Stirring is continued for 1.5 hours to ensure that the chemical treatment is fully carried out to obtain a deorganized printing and dyeing sludge.

[0057] The obtained deorganized printing and dyeing sludge was pumped to an alkalization treatment tank, 1.4 parts by weight of soda ash was added and stirred for 45 minutes to form an alkalized sludge with stable alkalinity;

[0058] Step 4: Alkalinization and drying treatment:

[0059] The alkalized sludge obtained in step three is pumped to a centrifugal dehydration device for solid-liquid separation to obtain alkalized printing and dyeing sludge with a certain water content, and then the water-containing alkalized printing and dyeing sludge is conveyed to a blast drying device for drying to obtain dry printing and dyeing sludge powder, that is, printing and dyeing sludge building material resource disposal material.

[0060] Example 3

[0061] This embodiment provides a method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning, which specifically includes the following steps:

[0062] Step 1: Pre-dehydration treatment:

[0063] The printing and dyeing sludge in a water-saturated state is added to a plate filter press for physical dehydration. During the filtration process, a 25-mesh sponge rubber outer filter cloth and a 100-mesh textile filter cloth are selected for filter pressing and dehydration of the printing and dyeing sludge. After the physical dehydration process, the moisture content of the printing and dyeing sludge is reduced to 75%, and a printing and dyeing sludge cake is obtained, namely, pre-dehydrated printing and dyeing sludge.

[0064] Step 2: Crushing and screening:

[0065] The printing and dyeing sludge cake obtained in step one is conveyed to an auger transmission device for cake crushing, and the printing and dyeing sludge cake is crushed into printing and dyeing sludge fragments with a particle size of 0.5 to 2.0 cm; the obtained fragments are transferred to a steam drying device equipped with spiral auger blades through a conveyor belt, hot steam is introduced into the equipment to dry the printing and dyeing sludge fragments, and at the same time, the auger is slowly rotated to further refine and crush the printing and dyeing sludge fragments to obtain particles with smaller particle size.

[0066] Start the grading vibrating screen to screen the obtained particles, and select two grading screens with mesh sizes of 19mm and 0.3mm to control the particle fineness. Large particles that cannot pass through the 19mm sieve are returned to the auger transmission equipment for further mechanical crushing, and particles that pass through the 19mm sieve but cannot pass through the 0.3mm sieve are returned to the steam drying equipment equipped with spiral auger blades for further refinement and crushing. The sludge particles that pass through the 0.3mm sieve are collected and used as refined printing and dyeing sludge.

[0067] Step 3: Harmless treatment:

[0068] The Fenton reaction is used to decompose the residual organic components in the refined printing and dyeing sludge obtained in step 2. Specifically, 12 parts by mass of the refined printing and dyeing sludge are transferred to a Fenton reaction tank, 8 parts by mass of water and 0.27 parts by mass of ferrous sulfate are added, and the mechanical stirring device of the equipment is turned on to form a printing and dyeing sludge slurry with a solid-liquid ratio of 1.5:1. Sulfuric acid is used to adjust the pH of the printing and dyeing sludge slurry to 3.0, and then 1.1 parts by mass of hydrogen peroxide are added. Stirring is continued for 1 hour to ensure that the chemical treatment is fully carried out to obtain a deorganized printing and dyeing sludge.

[0069] The obtained deorganized printing and dyeing sludge was pumped to an alkalization treatment tank, 1.2 parts by weight of industrial caustic soda was added and stirred for 15 minutes to form an alkalized sludge with stable alkalinity;

[0070] Step 4: Alkalinization and drying treatment:

[0071] The alkalized sludge obtained in step three is pumped to a centrifugal dehydration device for solid-liquid separation to obtain alkalized printing and dyeing sludge with a certain water content, and then the water-containing alkalized printing and dyeing sludge is conveyed to a blast drying device for drying to obtain dry printing and dyeing sludge powder, that is, printing and dyeing sludge building material resource disposal material.

[0072] Example 4

[0073] This embodiment provides a method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning, which specifically includes the following steps:

[0074] Step 1: Pre-dehydration treatment:

[0075] The printing and dyeing sludge in a water-saturated state is added to a plate filter press for physical dehydration. During the filtration process, a 25-mesh sponge rubber outer filter cloth and a 100-mesh textile filter cloth are selected for filter pressing and dehydration of the printing and dyeing sludge. After the physical dehydration process, the moisture content of the printing and dyeing sludge is reduced to 65%, and a printing and dyeing sludge cake is obtained, namely, pre-dehydrated printing and dyeing sludge.

[0076] Step 2: Crushing and screening:

[0077] The printing and dyeing sludge cake obtained in step one is conveyed to an auger transmission device for cake crushing, and the printing and dyeing sludge cake is crushed into printing and dyeing sludge fragments with a particle size of 0.5 to 2.0 cm; the obtained fragments are transferred to a steam drying device equipped with spiral auger blades through a conveyor belt, hot steam is introduced into the equipment to dry the printing and dyeing sludge fragments, and at the same time, the auger is slowly rotated to further refine and crush the printing and dyeing sludge fragments to obtain particles with smaller particle size.

[0078] Start the grading vibrating screen to screen the obtained particles, and select two grading screens with mesh sizes of 19mm and 0.3mm to control the particle fineness. Large particles that cannot pass through the 19mm sieve are returned to the auger transmission equipment for further mechanical crushing, and particles that pass through the 19mm sieve but cannot pass through the 0.3mm sieve are returned to the steam drying equipment equipped with spiral auger blades for further refinement and crushing. The sludge particles that pass through the 0.3mm sieve are collected and used as refined printing and dyeing sludge.

[0079] Step 3: Harmless treatment:

[0080] The Fenton reaction is used to decompose the residual organic components in the refined printing and dyeing sludge obtained in step 2. Specifically, 8 parts by mass of the refined printing and dyeing sludge are transferred to a Fenton reaction tank, 10 parts by mass of water and 0.30 parts by mass of ferrous sulfate are added, and the mechanical stirring device of the equipment is turned on to form a printing and dyeing sludge slurry with a solid-liquid ratio of 0.8:1. Sulfuric acid is used to adjust the pH of the printing and dyeing sludge slurry to 3.2, and then 1.2 parts by mass of hydrogen peroxide are added. Stirring is continued for 1.5 hours to ensure that the chemical treatment is fully carried out to obtain a deorganized printing and dyeing sludge.

[0081] The obtained deorganized printing and dyeing sludge was pumped to an alkalization treatment tank, 1.5 parts by weight of slaked lime was added and stirred for 30 minutes to form an alkalized sludge with stable alkalinity;

[0082] Step 4: Alkalinization and drying treatment:

[0083] The alkalized sludge obtained in step three is pumped to a centrifugal dehydration device for solid-liquid separation to obtain alkalized printing and dyeing sludge with a certain water content, and then the water-containing alkalized printing and dyeing sludge is conveyed to a blast drying device for drying to obtain dry printing and dyeing sludge powder, that is, printing and dyeing sludge building material resource disposal material.

[0084] Comparative Example 1

[0085] This comparative example provides a method for preparing sludge that has not been subjected to harmless treatment, which specifically comprises the following steps:

[0086] Step 1: Pre-dehydration treatment:

[0087] The printing and dyeing sludge in a water-saturated state is added to a plate filter press for physical dehydration. During the filtration process, a 25-mesh sponge rubber outer filter cloth and a 100-mesh textile filter cloth are selected for filter pressing and dehydration of the printing and dyeing sludge. After the physical dehydration process, the moisture content of the printing and dyeing sludge is reduced to 70%, and a printing and dyeing sludge cake is obtained, namely, pre-dehydrated printing and dyeing sludge.

[0088] Step 2: Crushing and screening:

[0089] The printing and dyeing sludge cake obtained in step one is conveyed to an auger transmission device for cake crushing, and the printing and dyeing sludge cake is crushed into printing and dyeing sludge fragments with a particle size of 0.5 to 2.0 cm; the obtained fragments are transferred to a steam drying device equipped with spiral auger blades through a conveyor belt, hot steam is introduced into the equipment to dry the printing and dyeing sludge fragments, and at the same time, the auger is slowly rotated to further refine and crush the printing and dyeing sludge fragments to obtain particles with smaller particle size.

[0090] Start the grading vibrating screen to screen the obtained particles, and select two grading screens with mesh sizes of 19mm and 0.3mm to control the particle fineness. Large particles that cannot pass through the 19mm sieve are returned to the auger transmission equipment for further mechanical crushing, and particles that pass through the 19mm sieve but cannot pass through the 0.3mm sieve are returned to the steam drying equipment equipped with spiral auger blades for further refinement and crushing. The sludge particles that pass through the 0.3mm sieve are collected and used as refined printing and dyeing sludge.

[0091] The printing and dyeing sludge powder obtained in Examples 1 to 4 and the refined printing and dyeing sludge prepared in Comparative Example 1 were used as raw materials to prepare the following Figure 2 The sludge brick shown has a volume of 40mm×40mm×40mm. The laboratory formula of the sludge brick is shown in Table 1:

[0092] Table 1

[0093]

[0094] The preparation method of sludge brick is as follows:

[0095] When preparing sludge bricks, first dry mix cement with the printing and dyeing sludge powder obtained in Examples 1 to 4 or the refined printing and dyeing sludge prepared in Comparative Example 1 for 1 to 2 minutes, then add river sand and continue dry mixing for 1 minute to form a uniform dry material mixture; keep the mixer running, slowly pour water into the mixer, and stir quickly for 2 to 4 minutes to form a uniform slurry; stop stirring, pour the slurry into the mold for vibration molding; cover the molded test piece with a waterproof film, place it at room temperature (20±2℃) and stand for 24 hours before demolding; the demolded test piece is continued to be placed under standard curing conditions for 27 days (20±2℃, 95%RH), and then the mechanical properties are tested. The compressive properties of the obtained sludge bricks were tested, and the results are shown in Table 2.

[0096] Table 2

[0097] Test items Load(kN) Strength (MPa) Example 1 36.08 22.6 Example 2 36.14 22.6 Example 3 38.71 24.2 Example 4 36.98 23.1 Comparative Example 1 11.15 7.0

[0098] The results are shown in Table 2. The sludge bricks prepared from the printing and dyeing sludge powder that has been harmlessly treated have higher compressive resistance. This is because during the harmless treatment process, harmful substances such as organic matter and heavy metals in the printing and dyeing sludge are removed, which changes the chemical composition of the sludge and increases the proportion of inorganic matter in the sludge. Thus, a more stable mineral structure is formed during the preparation of the sludge bricks, thereby improving the compressive strength of the bricks.

[0099] The printing and dyeing sludge building material resource disposal material obtained by the invention can replace 30% of ordinary silicate cement to prepare cement mortar, cement concrete and cement-based material imitation stone bricks and other building materials, such as Figure 3 and Figure 4 The figure shows the actual photos of the small-scale and pilot production specimens of sludge bricks prepared with the printing and dyeing sludge powder obtained by the present invention as raw material. The printing and dyeing sludge material obtained by the resource treatment method of printing and dyeing sludge building materials based on the non-burning low-temperature process of the present invention can partially replace 20-50% of ordinary Portland cement under the premise of meeting safety and use requirements, directly reducing the amount of cement, which can not only reduce the production cost of building materials, but also reduce the carbon footprint of building materials, and help the greening process of the civil engineering materials industry.

Claims

1. A method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning, characterized in that: The steps include: Step 1: Pre-dehydration treatment: The water content of the dyeing sludge in a water-saturated state is reduced to below the saturated water content by using the traditional physical industrial sludge dehydration method to obtain the pre-dehydrated dyeing sludge; Step 2: Crushing and screening: The pre-dehydrated printing and dyeing sludge obtained in step 1 is mechanically crushed to obtain fragments; the obtained fragments are further refined and crushed while being dried to obtain particles with a smaller particle size, the obtained particles are screened, the particles that have not passed the screening are returned for further crushing, and the particles that have passed the screening are the refined printing and dyeing sludge; Step 3: Harmless treatment: Decomposing the residual organic components in the fine printing and dyeing sludge obtained in step 2 by Fenton reaction to obtain deorganized printing and dyeing sludge; alkalizing the obtained deorganized printing and dyeing sludge to obtain alkalized sludge; Step 4: Drying: The alkalized sludge obtained in step three is subjected to solid-liquid separation and drying treatment to obtain printing and dyeing sludge powder.

2. The method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning according to claim 1 is characterized in that: Step 1: The traditional physical industrial sludge dehydration method includes plate filter press or centrifugal dehydration; the moisture content of the pre-dehydrated printing and dyeing sludge is 55-75%.

3. The method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning according to claim 1 or 2, characterized in that: The mechanical crushing in step 2 is to transfer the pre-dehydrated printing and dyeing sludge to the auger transmission equipment for crushing, and the particle size of the obtained fragments is 0.5 to 2.0 cm.

4. The method for recycling printing and dyeing sludge building materials based on a non-burning low-temperature process according to claim 3 is characterized in that: The fine crushing in step 2 is to transfer the obtained pieces to a steam drying device equipped with spiral auger blades, pass hot steam into the device to dry the pieces, and at the same time rotate the auger to further crush the pieces.

5. The method for recycling printing and dyeing sludge building materials based on a low-temperature process without burning according to claim 4 is characterized in that: The screening in step 2 is carried out using a graded vibrating screen, and two graded screens with mesh sizes of 19 mm and 0.3 mm are selected for fineness control. Particles that cannot pass through the 19 mm screen are returned for mechanical crushing, and particles that pass through the 19 mm screen but cannot pass through the 0.3 mm screen are returned for further fine crushing.

6. The method for recycling printing and dyeing sludge building materials based on a non-burning low-temperature process according to claim 5 is characterized in that: The Fenton reaction in step 3 is to place the refined printing and dyeing sludge obtained in step 2 and water in a Fenton reaction device, stir to obtain printing and dyeing sludge slurry, add inorganic acid solution to adjust the pH of the printing and dyeing sludge slurry to 2.5-3.5, add ferrous sulfate and hydrogen peroxide, and continue stirring to ensure that the Fenton reaction is fully carried out.

7. The method for recycling printing and dyeing sludge building materials based on a non-burning low-temperature process according to claim 6 is characterized in that: The mass ratio of the refined printing and dyeing sludge, water, ferrous sulfate and hydrogen peroxide is 7-12:7-10:0.20-0.35:0.80-1.20; the inorganic acid solution is sulfuric acid, and the continuous stirring time is 0.5-1.5 hours.

8. The method for recycling printing and dyeing sludge building materials based on a non-burning low-temperature process according to claim 7 is characterized in that: The alkalization treatment in step 3 is to add an alkaline compound to the deorganized printing and dyeing slurry and fully stir it for 15 to 45 minutes.

9. The method for recycling printing and dyeing sludge building materials based on a non-burning low-temperature process according to claim 8 is characterized in that: The alkaline compound is quicklime, industrial caustic soda, slaked lime or soda ash, and the amount of the alkaline compound added is calculated based on the mass ratio of the refined printing and dyeing sludge to the alkaline compound being 10:1.0-2.

0.

10. The method for recycling printing and dyeing sludge building materials based on a non-burning low-temperature process according to claim 9 is characterized in that: The solid-liquid separation in step 4 is carried out using a centrifugal dehydration device.

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