A method for preparing permeable bricks using aluminum ash

Abstract

The present invention discloses a method for preparing permeable bricks using aluminum ash, which belongs to the field of environmental engineering technology. The method comprises the following steps: S1, preparing a permeable brick base using bottom mud from a black and odorous water body as the main raw material, and uniformly adding nano-titanium dioxide into the permeable brick base; S2, preparing oily sludge and using the oily sludge to prepare an oily sludge binder; S3, processing the aluminum ash to prepare liquid polyaluminum chloride, which is crystallized to obtain powdered polyaluminum chloride; S4, adding the powdered polyaluminum chloride to the aluminum ash and grinding it again. The ground aluminum ash mixture is cross-linked with the oily sludge binder to form crystals coated on the permeable brick base; S5, calcining the permeable brick base coated with the crystals to obtain nano-titanium dioxide-loaded permeable bricks. This method can significantly increase the strength of the formed permeable bricks and improve the bonding ability of titanium dioxide with the permeable bricks.

Description

Technical Field

[0001] The invention provides a method for preparing permeable bricks by utilizing aluminum ash, and belongs to the technical field of environmental engineering. Background Art

[0002] One of the key factors limiting the effectiveness of black and odorous water treatment is sediment contamination. Sediment, which accumulates a large amount of pollutants, is a significant secondary source of water pollution. The large amount of sediment generated during dredging operations is also a major challenge in its disposal, and its treatment and disposal is currently a prominent issue in black and odorous water treatment. Existing technologies utilize sediment to create permeable bricks, which not only address sediment contamination but also leverage the permeability of these bricks to alleviate urban waterlogging, achieving two goals at once.

[0003] Publication No. CN110183204A discloses a nano-titanium dioxide-loaded permeable brick and a preparation method thereof. It discloses that a permeable brick substrate is prepared using bottom mud, a binder, and straw residue as raw materials, and a titanium dioxide precursor suspension is impregnated on the permeable brick substrate by a multiple impregnation method. After calcination, nano-titanium dioxide is evenly embedded in the pores of the permeable brick substrate.

[0004] The above-mentioned disclosure has the following deficiencies: since the raw materials for manufacturing permeable bricks are bottom mud, although the sand and slag in the bottom mud can form a pore structure and increase the permeability of the brick body, its strength is also reduced; at the same time, the fixation effect of loading titanium dioxide by impregnation with a titanium dioxide precursor suspension is poor. When the permeable bricks are in use, the loaded titanium dioxide is easily washed away and fallen off by water, thereby causing the loss of photocatalyst and affecting the self-cleaning effect of the permeable bricks. Summary of the Invention

[0005] The present invention provides a method for preparing permeable bricks using aluminum ash, which uses a sewage sludge binder and aluminum ash to react and cross-link to form crystals coated on the bottom mud, which can greatly increase the strength of the permeable bricks after molding, and uses the carbon source in the sewage sludge binder to adsorb titanium dioxide, thereby improving the bonding ability of titanium dioxide and the permeable bricks.

[0006] In order to solve the above problems, the present invention proposes a technical solution: a method for preparing permeable bricks using aluminum ash, comprising the following steps: S1, preparing a permeable brick matrix with black and odorous water body sludge as the main raw material, and uniformly adding nano-titanium dioxide into the permeable brick matrix; S2, preparing oily sludge, and using the oily sludge to prepare an oily sludge binder; S3, treating the aluminum ash to prepare liquid polyaluminum chloride, and crystallizing the liquid polyaluminum chloride to obtain powdered polyaluminum chloride; S4, adding the powdered polyaluminum chloride to the aluminum ash and grinding it again, and the ground aluminum ash mixture is cross-linked with the oily sludge binder to form crystals coated on the permeable brick matrix; S5, calcining the permeable brick matrix coated with the crystals to obtain a permeable brick loaded with nano-titanium dioxide.

[0007] As an improvement, in step S1, the amount of added sludge is 85%, the binder is 15%, the straw residue is 0.4%, and the loading amount of nano-titanium dioxide is 0.2 g / brick.

[0008] As an improvement, in step S5, the permeable brick matrix loaded with titanium dioxide is sintered at a sintering temperature of 1100° C. and a holding time of 1 hour.

[0009] As an improvement, in step S2, the oily sludge is pretreated. The specific treatment method is: the oily sludge is crushed to a particle size of <8mm, sent to a sedimentation tank, a certain amount of binder and water are added under stirring, and mixed evenly, and then centrifuged to remove the middle layer of water to obtain an oily sludge binder composed of oil, soil and binder.

[0010] As an improvement, in step S3, liquid polyaluminium chloride is prepared by an acid dissolution method using aluminium ash and hydrochloric acid as raw materials; first, the aluminium ash is pretreated and washed with water to remove water-soluble salts to reduce hydrochloric acid consumption; after treatment, the aluminium ash contains 30% alumina, then a hydrochloric acid solution is prepared and added to a reactor and heated to a certain temperature, then the aluminium ash is weighed and gradually added with the hydrochloric acid solution, continuously stirred and water is added, the reaction time is controlled at 6 to 12 hours, the reaction temperature is 96°C, after the reaction is completed, water is added to dilute the materials, the pH value is adjusted to 3.5-4.5, and the mixture is precipitated for 15-24 hours to obtain liquid polyaluminium chloride, and then powdered polyaluminium chloride is precipitated by crystallization.

[0011] As an improvement, in step S4, the aluminum oxide content in the aluminum ash is 70%, and the calcium oxide content is 2%; the mixing ratio of powdered polyaluminum chloride and aluminum ash is 2:8, and the mixed grinding particle size of powdered polyaluminum chloride and aluminum ash is 400-500 mesh.

[0012] As an improvement, in step S4, water is added during the cross-linking process of the aluminum ash mixture and the oily sludge binder, and the water reacts with calcium oxide to form calcium hydroxide; the organic matter and impurities in the oily sludge binder are cross-linked with the aluminum oxide and calcium hydroxide in the aluminum ash to form crystals of calcium aluminum silicate gel.

[0013] As an improvement, in step S4, a stabilizer, which may be a zirconate or a titanate, is added during the cross-linking process of the aluminum ash mixture and the oil sludge binder, so as to change the crystal structure of the calcium aluminum silicate gel during the crystallization process.

[0014] As an improvement, in step S2, the asphaltene content in the oily sludge is 8-12%, the paraffin content is 5-8%, the oil content is ≥40%, and the ash content is 3-5%; the mixing ratio of the binder to the oily sludge is 4:6; and the large amount of carbon source in the oily sludge has the function of adsorbing titanium dioxide.

[0015] Beneficial effects of the present invention:

[0016] 1. In the method for preparing permeable bricks of the present invention, nano-titanium dioxide is loaded on the permeable bricks, so that the bricks not only have a water-permeable function, but also can use titanium dioxide as a photocatalyst to catalytically degrade pollutants that pass through the brick body and some pollutants attached to the surface of the brick body, with good self-cleaning performance, effectively extending the service life of the permeable brick substrate.

[0017] 2. The aluminum ash mixture cross-links with the oily sludge binder to form crystals coated on the permeable brick base. The large amount of carbon source in the oily sludge binder can adsorb titanium dioxide, thereby improving the binding ability of titanium dioxide to the permeable brick, preventing the loss of titanium dioxide loaded on the permeable brick and increasing the self-cleaning function of the permeable brick. At the same time, the crystals of calcium aluminum silicate gel coated on the permeable brick base can greatly increase the strength of the permeable brick. At the same time, the addition of stabilizers such as zirconate or titanate can change the crystal structure of the calcium aluminum silicate gel during crystal formation, thereby increasing its high temperature resistance and ensuring that the crystal structure is not destroyed during high-temperature calcination of the brick.

[0018] 3. Process aluminum ash to produce liquid polyaluminum chloride, and crystallize the liquid polyaluminum chloride to obtain powdered polyaluminum chloride; use aluminum ash to make powdered polyaluminum chloride. Polyaluminum chloride is a high-performance inorganic polymer flocculant with the characteristics of large molecular structure, strong adsorption and cohesion, large flocs formed, and low dosage. It has a fast flocculation and sedimentation speed and can effectively remove color and heavy metal ions in water, thereby increasing the cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flow chart of a method for preparing permeable bricks using aluminum ash. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] according to Figure 1 As shown: The present invention provides a method for preparing permeable bricks using aluminum ash: comprising the following steps: S1, preparing a permeable brick matrix with black and odorous water body sludge as the main raw material, and uniformly adding nano-titanium dioxide into the permeable brick matrix; S2, preparing oily sludge, and using the oily sludge to prepare an oily sludge binder; S3, processing the aluminum ash to prepare liquid polyaluminum chloride, and crystallizing the liquid polyaluminum chloride to obtain powdered polyaluminum chloride; S4, adding the powdered polyaluminum chloride to the aluminum ash and grinding it again, and cross-linking the ground aluminum ash mixture with the oily sludge binder to generate crystals coated on the permeable brick matrix; S5, calcining the permeable brick matrix coated with the crystals to obtain a permeable brick loaded with nano-titanium dioxide.

[0022] In step S1, the added amount of bottom mud is 85%, the binder is 15%, the straw residue is 0.4%, and the loading amount of nano-titanium dioxide is 0.2 g / brick.

[0023] In step S5, the permeable brick matrix loaded with titanium dioxide is sintered at a sintering temperature of 1100° C. and a holding time of 1 hour.

[0024] In step S2, the oily sludge is pretreated. The specific treatment method is as follows: the oily sludge is crushed to a particle size of <8 mm, sent to a sedimentation tank, a certain amount of binder and water are added under stirring, mixed evenly, and then centrifuged to remove the middle layer of water to obtain an oily sludge binder composed of oil, soil, and binder.

[0025] In step S3, liquid polyaluminium chloride is prepared by acid dissolution using aluminium ash and hydrochloric acid as raw materials; first, the aluminium ash is pretreated and washed with water to remove water-soluble salts to reduce hydrochloric acid consumption; after treatment, the aluminium ash contains 30% aluminium oxide, then a hydrochloric acid solution is prepared and added to a reactor and heated to a certain temperature, then the aluminium ash is weighed and gradually added with hydrochloric acid solution, continuously stirred and water is added, the reaction time is controlled to be 6 to 12 hours, the reaction temperature is 96°C, after the reaction is completed, water is added to dilute the material, the pH value is adjusted to 3.5-4.5, and the liquid polyaluminium chloride is obtained by precipitation for 15-24 hours, and then powdered polyaluminium chloride is precipitated by crystallization. In step S4, the aluminium oxide content in the aluminium ash is 70% and the calcium oxide content is 2%; the mixing ratio of powdered polyaluminium chloride and aluminium ash is 2:8, and the mixed grinding particle size of the powdered polyaluminium chloride and aluminium ash is 400-500 mesh.

[0026] The aluminum in polyaluminum chloride exists in the form of multivalent ions, such as Al3+. Multivalent ions have a high charge density and adsorption capacity, allowing them to form chemical complexes with heavy metal ions. This chemical complexation can adsorb heavy metal ions through mechanisms such as charge neutralization, electrostatic attraction, and complex ion effects. When water passes through permeable bricks, some aluminum ions react with hydroxides in the water to form aluminum hydroxide precipitates. These hydroxide precipitates can adsorb heavy metal ions and form solid particles, allowing them to be removed or separated. Furthermore, polyaluminum chloride, due to its high molecular weight and polymer properties, can form granular aggregates in water. These aggregates have a large surface area and internal pores, providing more adsorption sites, effectively capturing and adsorbing heavy metal ions. Therefore, adding polyaluminum chloride to aluminum ash can enhance the permeable brick's ability to adsorb heavy metal ions and improve its cleaning performance.

[0027] In step S4, water is added during the crosslinking process between the aluminum ash mixture and the oily sludge binder. The water reacts with calcium oxide to form calcium hydroxide. Organic matter and impurities in the oily sludge binder crosslink with the aluminum oxide and calcium hydroxide in the aluminum ash to form crystals of calcium aluminosilicate gel. In step S4, a stabilizer, such as a zirconate or titanate, is added during the crosslinking process between the aluminum ash mixture and the oily sludge binder to modify the crystal structure of the calcium aluminosilicate gel during its formation.

[0028] Calcium aluminum silicate gel has a uniform and continuous microporous structure, characterized by low density, large pore size, small crystal size, large internal area, high hardness, and good chemical stability. Therefore, it can exhibit good strength and hardness without affecting the permeability of permeable bricks. The crystal structure of calcium aluminum silicate gel is mainly composed of two parts: silicate gelation and hydrated calcium aluminate crystal structure. When zirconate or titanate admixtures are added, the components of these admixtures can react with the permeable brick preparation process to produce new compounds with a similar crystal structure to hydrated calcium aluminate. This forms a microstructure and crystal morphology different from ordinary cement, thereby improving its high-temperature resistance.

[0029] In step S2, the asphaltene content in the oily sludge is 8-12%, the paraffin content is 5-8%, the oil content is ≥40%, and the ash content is 3-5%; the mixing ratio of the binder to the oily sludge is 4:6; and the large amount of carbon source in the oily sludge has the function of adsorbing titanium dioxide.

[0030] Example 1

[0031] 2kg of black and odorous water sludge was used as the main raw material for permeable bricks. A binder and straw residue were added, so that the sludge accounted for 85% of the permeable brick base, the binder was 15%, and the straw residue was 0.4%. 0.2g of nano-titanium dioxide was also prepared. Oily sludge was prepared, with an asphaltene content of 8%, a paraffin content of 5%, an oil content of 40%, and an ash content of 3%. The binder and oily sludge were evenly mixed in a ratio of 4:6 to create the oily sludge binder. Liquid polyaluminium chloride is prepared by an acid dissolution method using aluminium ash and hydrochloric acid as raw materials. First, the aluminium ash is pretreated and washed with water to remove water-soluble salts to reduce hydrochloric acid consumption. After treatment, the aluminium ash contains 30% alumina. A hydrochloric acid solution is then prepared and added to a reactor and heated to a certain temperature. The aluminium ash is weighed and gradually added with the hydrochloric acid solution while stirring continuously and adding water. The reaction time is controlled at 6 hours and the reaction temperature is 96°C. After the reaction is completed, water is added to dilute the material, the pH value is adjusted to 3.5, and the liquid polyaluminium chloride is obtained by precipitation for 15 hours, and then powdered polyaluminium chloride is precipitated by crystallization.

[0032] Aluminum ash containing 70% aluminum oxide and 2% calcium oxide is mixed and ground with powdered polyaluminum chloride in a ratio of 2:8. The mixture is ground to a 400-mesh size to produce an aluminum ash mixture. This mixture is then coated with a sludge binder and applied to a titanium dioxide and permeable brick substrate. The aluminum ash mixture and the sludge binder are cross-linked, and zirconate is added to form crystals of a calcium aluminum silicate gel with a modified crystal structure and high temperature resistance. These crystals are then coated on the permeable brick. The titanium dioxide-loaded permeable brick substrate is sintered at 1100°C for 1 hour, resulting in a high-strength permeable brick that resists titanium dioxide detachment.

[0033] Example 2

[0034] 2kg of black and odorous water body sludge was used as the main raw material for permeable bricks. A binder and straw residue were added, so that the sludge accounted for 85% of the permeable brick base, the binder accounted for 15%, and the straw residue accounted for 0.4%. 0.2g of nano-titanium dioxide was also prepared. Oily sludge was prepared, with an asphaltene content of 12%, a paraffin content of 8%, an oil content of 45%, and an ash content of 5%. The binder and oily sludge were evenly mixed in a ratio of 4:6 to create the oily sludge binder. Liquid polyaluminium chloride is prepared by an acid dissolution method using aluminium ash and hydrochloric acid as raw materials. First, the aluminium ash is pretreated and washed with water to remove water-soluble salts to reduce hydrochloric acid consumption. After treatment, the aluminium ash contains 30% alumina. Then, a hydrochloric acid solution is prepared and added to a reactor and heated to a certain temperature. After that, the aluminium ash is weighed and the hydrochloric acid solution is gradually added. The mixture is continuously stirred and water is added. The reaction time is controlled at 12 hours and the reaction temperature is 96°C. After the reaction is completed, water is added to dilute the materials, the pH value is adjusted to 4.5, and the mixture is precipitated for 24 hours to obtain liquid polyaluminium chloride, which is then crystallized to obtain powdered polyaluminium chloride.

[0035] Aluminum ash containing 80% aluminum oxide and 2% calcium oxide is mixed and ground with powdered polyaluminum chloride in a ratio of 2:8. The mixture is ground to a 500-mesh size to produce an aluminum ash mixture. This mixture is then coated with a sludge binder and applied to a titanium dioxide and permeable brick substrate. The aluminum ash mixture and the sludge binder are cross-linked, and zirconate is added to form crystals of a calcium aluminum silicate gel with a modified crystal structure and high temperature resistance. These crystals are then coated on the permeable brick. The titanium dioxide-loaded permeable brick substrate is sintered at 1100°C for 1 hour, resulting in a high-strength permeable brick that resists titanium dioxide detachment.

[0036] The present invention and its embodiments are described above. Such description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto.

Claims

1. A method for preparing permeable bricks using aluminum ash, characterized in that: The following steps are involved: S1. Prepare a permeable brick matrix with black and odorous water body sludge as the main raw material, and evenly add nano-titanium dioxide into the permeable brick matrix; S2. Prepare oily sludge, and use the oily sludge to make an oily sludge binder; S3. Treat aluminum ash to make liquid polyaluminum chloride, and crystallize the liquid polyaluminum chloride to obtain powdered polyaluminum chloride; S4. Add the powdered polyaluminum chloride to aluminum ash containing calcium oxide and grind it again. The ground aluminum ash mixture is cross-linked with the oily sludge binder to form crystals coated on the permeable brick matrix; S5. Calcinate the permeable brick matrix coated with the crystals to obtain a permeable brick loaded with nano-titanium dioxide.

2. The method for preparing permeable bricks using aluminum ash according to claim 1, characterized in that: In step S1, the amount of added sediment is 85%, the binder is 15%, the straw residue is 0.4%, and the loading amount of nano-titanium dioxide is 0.2 g / brick.

3. The method for preparing permeable bricks using aluminum ash according to claim 2, characterized in that: In step S5, the permeable brick matrix loaded with titanium dioxide is sintered at a sintering temperature of 1100° C. and a holding time of 1 hour.

4. The method for preparing permeable bricks using aluminum ash according to claim 1, characterized in that: In step S2, the oily sludge is pretreated. The specific treatment method is as follows: the oily sludge is crushed to a particle size of <8 mm, sent to a sedimentation tank, a certain amount of binder and water are added under stirring, mixed evenly, and then centrifuged to remove the middle layer of water to obtain an oily sludge binder composed of oil, soil, and binder.

5. The method for preparing permeable bricks using aluminum ash according to claim 1, characterized in that: In step S3, liquid polyaluminium chloride is prepared by an acid dissolution method using aluminium ash and hydrochloric acid as raw materials; first, the aluminium ash is pre-treated and washed with water to remove water-soluble salts to reduce hydrochloric acid consumption; After treatment, the aluminum ash contains 30% aluminum oxide. Then, a hydrochloric acid solution is prepared and added to the reactor and heated to a certain temperature. Then, the aluminum ash is weighed and gradually added with the hydrochloric acid solution. Stirring is continued and water is added. The reaction time is controlled at 6 to 12 hours and the reaction temperature is 96°C. After the reaction is completed, water is added to dilute the material and the pH value is adjusted to 3.5-4.

5. The liquid polyaluminum chloride is obtained by precipitation for 15-24 hours, and then powdered polyaluminum chloride is precipitated by crystallization.

6. The method for preparing permeable bricks using aluminum ash according to claim 1, characterized in that: In step S4, the aluminum oxide content in the aluminum ash is 70%-80%, and the calcium oxide content is 2%; the mixing ratio of powdered polyaluminum chloride and aluminum ash is 2:8, and the mixed grinding particle size of the powdered polyaluminum chloride and aluminum ash is 400-500 mesh.

7. The method for preparing permeable bricks using aluminum ash according to claim 1, characterized in that: In step S4, water is added during the cross-linking process of the aluminum ash mixture and the oily sludge binder, and the water reacts with calcium oxide to form calcium hydroxide; the organic matter and impurities in the oily sludge binder are cross-linked with the aluminum oxide and calcium hydroxide in the aluminum ash to form crystals of calcium aluminum silicate gel.

8. The method for preparing permeable bricks using aluminum ash according to claim 7, characterized in that: In step S4, a stabilizer is added during the cross-linking process of the aluminum ash mixture and the oil sludge binder. The stabilizer is zirconate or titanate, so as to change the crystal structure of the calcium aluminum silicate gel during the crystallization process.

9. The method for preparing permeable bricks using aluminum ash according to claim 1, characterized in that: In step S2, the asphaltene content in the oily sludge is 8%-12%, the paraffin content is 5%-8%, the oil content is ≥40%, and the ash content is 3%-5%; the mixing ratio of the binder to the oily sludge is 4:6; and the large amount of carbon source in the oily sludge has the function of adsorbing titanium dioxide.

Images