Waste residue soil solidified baking-free blank brick

Abstract

The invention relates to the technical field of residue soil baking-free brick building materials, and discloses a waste residue soil solidified baking-free blank brick which is prepared from the following components in parts by weight: 1500-1600 parts of waste residue soil, 20-30 parts of polypropylene fiber, 150-170 parts of a curing agent, 3-8 parts of a powder enhancer, 0.5-3 parts of a hyperbranched naphthalene water reducer and 180-190 parts of water. The preparation method of the hyperbranched naphthalene water reducer comprises the following steps: by taking naphthalene as a raw material, sulfonating with concentrated sulfuric acid, and carrying out condensation reaction with branched naphthol phosphate and formaldehyde, thereby obtaining the hyperbranched naphthalene water reducer. The waste residue soil solidified baking-free blank brick has excellent compressive strength, and can reach the performance standard of tailing bricks with the strength grade of MU15 in JC / T422-2007 Non-Sintered Rubbish Tailing Brick.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials for non - fired muck bricks, and specifically relates to a solidified non - fired green brick made of waste muck. Background Technique

[0002] Construction muck is the waste soil generated in construction projects such as tunnels, subways, foundation pits, and underground pipe corridors. In China, more than 119 million tons of construction muck are produced annually, but its resource utilization rate is less than 1%. Currently, construction waste muck is generally directly transported to remote places such as suburbs and is treated by open stacking, incineration, and landfill. The stacking of waste muck will bring a series of problems, such as occupying a large amount of land, polluting the surrounding environment, and affecting the urban appearance.

[0003] In order to improve the comprehensive utilization rate and added value of waste muck, using soil solidification technology to produce non - fired muck bricks has gradually become the development trend of the industry. For example, the invention patent application with the publication number CN111825375A discloses a method for solidifying muck and preparing non - fired bricks, which mixes raw materials such as muck, cement, acrylic acid, magnesium chloride, and water, cures, and presses them into shape to achieve harmless solidification treatment of muck and prepare non - fired bricks; the invention patent with the authorization number CN107285727B makes bricks by extruding and dehydrating mud muck and mixing it with a soil coagulant. Non - fired bricks can generate strength without sintering, overcoming the disadvantages of ordinary sintered clay bricks, such as consuming a large amount of coal resources, high energy consumption, and environmental pollution, and conforming to the trend of waste utilization, soil conservation, energy conservation, environmental protection, and sustainable development.

[0004] The solidified non - fired green brick made of waste muck is a product that adds solidifying agents (cement, lime, fly ash, slag), water - reducing agents (naphthalene - based water - reducing agent, polycarboxylate water - reducing agent, melamine - based water - reducing agent, phosphoric acid water - reducing agent), and other additives (powder strengthening agent, mud inhibitor, antifreeze) to waste muck and is solidified and pressed into shape through physical, chemical, and composite actions. Among them, the water - reducing agent can promote the formation of hydration products, reduce the voids in the process of waste muck solidification, and improve the compaction performance and mechanical strength of non - fired green bricks, and is one of the key components in the solidified non - fired green brick made of waste muck. Summary of the Invention

[0005] The present invention independently developed a solidified non - fired green brick made of waste muck, which has excellent compressive strength and can meet the performance standards of tailings bricks with a strength grade of MU15 in JC / T 422 - 2007 "Non - sintered Waste Tailings Bricks".

[0006] A solidified non - fired green brick made of waste muck, the raw material formula of the solidified non - fired green brick made of waste muck is as follows:

[0007] Waste muck, 1500 - 1600 parts by weight;

[0008] Polypropylene fiber, 20 - 30 parts by weight;

[0009] Curing agent, 150 - 170 parts by weight;

[0010] Powder strengthening agent, 3 - 8 parts by weight;

[0011] Hyperbranched naphthalene - based water - reducing agent, 0.5 - 3 parts by weight;

[0012] Water, 180 - 190 parts by weight;

[0013] Among them, the preparation method of the hyperbranched naphthalene - based water - reducing agent is: using naphthalene as raw material, first sulfonating with concentrated sulfuric acid, and then carrying out a condensation reaction with branched naphthol phosphate and formaldehyde;

[0014] The branched naphthol phosphate is a three - branched naphthol phosphate or a four - branched naphthol phosphate;

[0015] Preferably, the formula of the curing agent is: 5 - 10 parts by weight of chemical special soil curing agent, 25 - 35 parts by weight of quicklime, and 120 - 125 parts by weight of cement.

[0016] Preferably, the powder strengthening agent is starch or polyvinyl alcohol.

[0017] Preferably, the preparation method of the waste soil and slag solidified non - fired brick is:

[0018] Step 1, pretreatment of waste soil and slag: The waste soil and slag with water content below 60% is crushed into slag with a size of 3 - 7 mm by a gear clay crusher for standby;

[0019] Step 2, according to the formula of the waste soil and slag solidified non - fired brick, mix polypropylene fiber, chemical special soil curing agent, quicklime, cement, starch and hyperbranched naphthalene - based water - reducing agent evenly, then mix with the waste soil and slag, add water and stir. After stirring evenly, put it into a mold for pressing, and statically press for 8 - 12 s at a pressure of 15 - 25 MPa to form. Then carry out steam curing at 70 - 90 °C for 20 - 30 h or natural curing at 15 - 25 °C for 25 - 30 days to obtain the waste soil and slag solidified non - fired brick.

[0020] Preferably, the compressive strength of the waste soil and slag solidified non - fired brick > 18 MPa.

[0021] Beneficial effects:

[0022] Based on the molecular design mechanism, the present invention synthesizes two kinds of branched naphthol phosphates, and carries out a condensation reaction with sulfonated naphthalene and formaldehyde to prepare a hyperbranched naphthalene - based water - reducing agent;

[0023] Using waste soil and slag as raw materials, polypropylene fiber as anti-cracking enhancer, chemical special soil curing agent, quicklime and cement as curing agents, starch as powder strengthening agent, and hyperbranched naphthalene-based water reducer as water reducer, after mixing evenly, it is pressed into shape to prepare a waste soil and slag solidified non-fired brick;

[0024] It can be seen from the experimental results that compared with the conventional non-fired bricks prepared by using conventional naphthalene-based water reducers, the non-fired bricks prepared by the present invention using the newly developed hyperbranched naphthalene-based water reducer have achieved beneficial technical effects of significant improvement in compressive strength performance. Description of the Drawings

[0025] Figure 1 It is a bar chart of the experimental results of the performance of waste soil and slag solidified non-fired bricks.

[0026] Figure 2 It is the chemical structural formula of the three-branched naphthol monomer;

[0027] Figure 3 It is the chemical structural formula of the three-branched naphthol phosphate;

[0028] Figure 4 It is the chemical structural formula of the four-branched naphthol monomer;

[0029] Figure 5 It is the chemical structural formula of the four-branched naphthol phosphate. Detailed Embodiments

[0030] Example 1:

[0031] A waste soil and slag solidified non-fired brick, and its raw material formula is shown in Table 1;

[0032] Table 1 Raw material formula of waste soil and slag solidified non-fired brick

[0033]

[0034]

[0035] Among them, the hyperbranched naphthalene-based water reducer is hyperbranched naphthalene-based water reducer I or hyperbranched naphthalene-based water reducer II. The preparation method of hyperbranched naphthalene-based water reducer I is recorded in Experimental Example 1, and the preparation method of hyperbranched naphthalene-based water reducer II is recorded in Experimental Example 2.

[0036] Example 2:

[0037] A preparation method of a waste soil and slag solidified non-fired brick, comprising the following steps:

[0038] Step 1, pretreatment of waste soil and slag: The waste soil and slag with 50% water content are crushed into 5 mm slag by a gear clay crusher for standby;

[0039] Step 2: According to the formula of waste soil solidified non-fired bricks in Table 1, mix polypropylene fiber, chemical special soil curing agent, quicklime, cement, starch and hyperbranched naphthalene-based water reducer evenly, then mix them with waste soil. Add water according to the ratio and stir for 30 minutes. Weigh 140 g of the evenly stirred sample, place it in a mold and press it. Static pressure is applied at 20 MPa for 10 s to form (the test blocks are all cubic blocks of 40 mm × 40 mm × 40 mm), and steam curing is carried out at 80 °C for 24 h to obtain waste soil solidified non-fired bricks;

[0040] When the hyperbranched naphthalene-based water reducer is hyperbranched naphthalene-based water reducer I, the prepared product is denoted as waste soil solidified non-fired brick I;

[0041] When the hyperbranched naphthalene-based water reducer is hyperbranched naphthalene-based water reducer II, the prepared product is denoted as waste soil solidified non-fired brick II.

[0042] Control example:

[0043] Prepare conventional non-fired bricks: Use conventional naphthalene-based water reducer to replace the hyperbranched naphthalene-based water reducer in waste soil solidified non-fired bricks, and prepare conventional non-fired bricks according to the same steps and conditions;

[0044] Among them, the preparation method of the conventional naphthalene-based water reducer is recorded in Experimental Example 3.

[0045] Performance test:

[0046] (1) Mechanical property test: Cool the test blocks cured by steam at 80 °C for 24 h to room temperature, and use a YAW-300YD type constant stress pressure testing machine with a maximum output pressure of 300 kN and a set loading speed of 2.4 kN / s for testing, and record the compressive strength of the test blocks;

[0047] (2) Refer to GB / T 4111-2013 "Test Methods for Concrete Blocks and Bricks" to test the water absorption rate and softening coefficient of the test blocks;

[0048] The above experimental results are shown in Table 2 below and Figure 1 .

[0049] Table 2 Performance experimental results of waste soil solidified non-fired bricks

[0050] Product type Compressive strength (MPa) Water absorption rate (%) Softening coefficient Non-fired green brick Ⅰ 18.7 10.2 0.79 Non-fired green brick Ⅱ 21.4 9.5 0.85 Control example 13.2 7.6 0.81 Technical requirements ≥15 ≤18 ≥0.8

[0051] Note: The technical requirements are based on the performance of tailings bricks with a strength grade of MU15 in JC / T 422-2007 "Non-sintered Waste Tailings Bricks";

[0052] Through comprehensive analysis of the above experimental results, the following conclusions can be drawn:

[0053] Conclusion 1: Compared with the conventional non-fired green bricks prepared by using conventional naphthalene-based water reducers, the non-fired green bricks prepared by using the newly developed hyperbranched naphthalene-based water reducer of the present invention have achieved a beneficial technical effect of significant improvement in terms of compressive strength performance;

[0054] Among them, the hyperbranched naphthalene-based water reducer II prepared from tetra-branched naphthol phosphate has a better effect on improving the compressive strength performance of non-fired green bricks;

[0055] The mechanism for the above experimental results may be as follows: On the one hand, the hyperbranched naphthalene-based water reducer increases the contact area between the water reducer molecules and the waste soil and solidifying agent particles. On the other hand, the spatial structure of the hyperbranched naphthalene-based water reducer can increase the steric hindrance effect, improve the fluidity of the waste soil and solidifying agent particles, reduce the voids during the process of solidifying non-fired green bricks with waste soil, and thus improve the compressive strength of non-fired green bricks;

[0056] Conclusion 2: The non-fired green bricks solidified with waste soil prepared by the present invention have excellent comprehensive performance and can all meet the performance standards of tailing bricks with a strength grade of MU15 in JC / T422-2007 "Non-sintered Garbage Tailings Bricks".

[0057] Experimental Example 1:

[0058] Prepare hyperbranched naphthalene-based water reducer I, and its preparation process is as follows:

[0059] (1) Synthesize tri-branched naphthol phosphate, and its synthesis steps are as follows:

[0060] The first step: Through the esterification reaction of the hydroxyl functional group of glycerol with the carboxyl functional group of 2-hydroxy-6-naphthoic acid, a tri-branched naphthol monomer is formed, and its chemical structural formula is as Figure 2 shown;

[0061] The second step: Through the catalysis of an organic base catalyst, the tri-branched naphthol monomer reacts with phosphorus oxychloride by esterification, and then water is added for hydrolysis to generate tri-branched naphthol phosphate, and its chemical structural formula is as Figure 3 shown;

[0062] Among them, the organic base catalyst is one of triethylamine, pyridine, and tetramethylethylenediamine; in this experimental example, pyridine is selected for use;

[0063] The specific experimental steps for preparing tri-branched naphthol phosphate are as follows:

[0064] 0.9 g of glycerol, 5.6 g of 2-hydroxy-6-naphthoic acid and 60 mL of N,N-dimethylformamide were added to a three-necked flask, stirred at room temperature until completely dissolved, and then 1.2 mL of concentrated sulfuric acid was added dropwise to the three-necked flask. The temperature was raised to 70 °C and stirred for 6 h. It was washed successively with N,N-dimethylformamide and deionized water, the solvent was removed by rotary evaporation, and vacuum dried to obtain a three-branched naphthol monomer;

[0065] 3.0 g of the three-branched naphthol monomer and 50 mL of anhydrous toluene were added to a three-necked flask, stirred at room temperature until completely dissolved, and then 1.4 mL of phosphorus oxychloride was added dropwise to the three-necked flask. After the temperature was raised to 80 °C, 0.6 mL of pyridine was slowly added dropwise, and the reaction was stirred at 80 °C for 5 h. After cooling, it was filtered and distilled under reduced pressure. 100 mL of deionized water was added, stirred and hydrolyzed for 2 h, filtered by suction, and vacuum dried to obtain a three-branched naphthol phosphate ester;

[0066] The 1H NMR characterization of the three-branched naphthol phosphate ester was as follows: 1 H NMR(CDCl 3 , 400 MHz) δ: 4.42 - 4.44 (d, 4H), 4.94 - 5.01 (m, 1H), 7.14 - 8.60 (m, 18H, Ar-H);

[0067] (2) Preparation of hyperbranched naphthalene-based water reducer Ⅰ: Using naphthalene as the raw material, first sulfonated by concentrated sulfuric acid, and then condensed with the three-branched naphthol phosphate ester and formaldehyde to prepare hyperbranched naphthalene-based water reducer Ⅰ. The specific preparation steps were as follows: 10 g of flaky industrial naphthalene was heated and melted and then put into a four-necked flask. Under the protection of nitrogen, 20 mL of concentrated sulfuric acid was added dropwise, and the temperature was raised to 160 °C and stirred for 2 h. After cooling to room temperature, deionized water was added to adjust the acid value to 29%. Then 2 g of the three-branched naphthol phosphate ester and 3 g of formaldehyde were added to the four-necked flask, and the temperature was raised to 130 °C and stirred for 12 h. After cooling to room temperature, sodium hydroxide was added to neutralize to pH = 7 to obtain hyperbranched naphthalene-based water reducer Ⅰ.

[0068] Experimental Example 2:

[0069] Preparation of hyperbranched naphthalene-based water reducer Ⅱ, and its preparation process was as follows:

[0070] (1) Synthesis of tetra-branched naphthol phosphate ester, and its synthesis steps were as follows:

[0071] The first step: An esterification reaction occurred between the hydroxyl functional group of pentaerythritol and the carboxyl functional group of 2-hydroxy-6-naphthoic acid to generate a tetra-branched naphthol monomer, and its chemical structural formula was as Figure 4 shown;

[0072] Step 2: Catalyze the esterification reaction of the tetra-branched naphthol monomer with phosphorus oxychloride by an organic base catalyst, and then add water for hydrolysis to generate tetra-branched naphthol phosphate ester, whose chemical structural formula is as Figure 5 shown;

[0073] Among them, the organic base catalyst is one of triethylamine, pyridine, and tetramethylethylenediamine; in this experimental example, pyridine is selected for use;

[0074] The specific experimental steps for preparing tetra-branched naphthol phosphate ester are as follows:

[0075] Add 1.3 g of glycerol, 7.5 g of 2-hydroxy-6-naphthoic acid, and 80 mL of N,N-dimethylformamide into a three-necked flask, stir at room temperature until completely dissolved, then add 1.5 mL of concentrated sulfuric acid dropwise to the three-necked flask, raise the temperature to 70 °C and stir for 8 h, wash successively with N,N-dimethylformamide and deionized water, remove the solvent by rotary evaporation, and dry in vacuum to obtain tetra-branched naphthol monomer;

[0076] Add 4.1 g of tetra-branched naphthol monomer and 50 mL of anhydrous toluene into a three-necked flask, stir at room temperature until completely dissolved, then add 1.9 mL of phosphorus oxychloride dropwise to the three-necked flask, slowly drop 0.7 mL of pyridine after raising the temperature to 80 °C, keep stirring at 80 °C for 6 h, filter after cooling and distill under reduced pressure, add 100 mL of deionized water, stir for hydrolysis for 2 h, filter by suction, and dry in vacuum to obtain tetra-branched naphthol phosphate ester;

[0077] The nuclear magnetic resonance hydrogen spectrum characterization of tetra-branched naphthol phosphate ester is as follows: 1 H NMR(CDCl 3 , 400 MHz)δ: 4.44(s, 8H), 7.13 - 8.62(m, 24H, Ar-H);

[0078] (2) Preparation of hyperbranched naphthalene-based water reducer II: Using naphthalene as the raw material, first carry out sulfonation with concentrated sulfuric acid, and then carry out a condensation reaction with tetra-branched naphthol phosphate ester and formaldehyde to prepare hyperbranched naphthalene-based water reducer II. The specific preparation steps are only different from those of hyperbranched naphthalene-based water reducer I in that: tetra-branched naphthol phosphate ester is used to replace tri-branched naphthol phosphate ester.

[0079] Experimental example 3:

[0080] Preparation of conventional naphthalene-based water reducer: Heat and melt 10 g of flaky industrial naphthalene and put it into a four-necked flask. Under the protection of nitrogen, add 20 mL of concentrated sulfuric acid dropwise, raise the temperature to 160 °C and stir for 2 h, cool to room temperature, add deionized water to adjust the acid value to 29%, then add 3 g of formaldehyde to the four-necked flask, raise the temperature to 130 °C and stir for 12 h, cool to room temperature, and add sodium hydroxide to neutralize to pH = 7 to obtain conventional naphthalene-based water reducer.

Claims

1. A waste slag solidified unfired green brick, characterized in that: The raw material formula of the waste slag soil solidified unfired green brick is: Waste soil, 1500-1600 parts by weight; Polypropylene fiber, 20-30 parts by weight; Curing agent, 150-170 parts by weight; Powder strengthener, 3-8 parts by weight; Hyperbranched naphthalene water reducing agent, 0.5-3 parts by weight; Water, 180-190 parts by weight; The preparation method of the hyperbranched naphthalene water reducer is as follows: naphthalene is used as a raw material, firstly sulfonated with concentrated sulfuric acid, and then condensed with branched naphthol phosphate and formaldehyde to obtain the hyperbranched naphthalene water reducer; The branched naphthol phosphate is a three-branched naphthol phosphate or a four-branched naphthol phosphate; The chemical structure of the three-branched naphthol phosphate is: The chemical structure of tetra-branched naphthol phosphate is:

2. The waste slag soil solidified unfired green brick according to claim 1, characterized in that: The preparation method of the three-branched naphthol phosphate is: The hydroxyl functional group of glycerol and the carboxyl functional group of 2-hydroxy-6-naphthoic acid undergo an esterification reaction to generate a three-branched naphthol monomer; The tri-branched naphthol monomer is catalyzed by an organic base catalyst to undergo an esterification reaction with phosphorus oxychloride, and then water is added for hydrolysis to generate a tri-branched naphthol phosphate.

3. The waste slag soil solidified unfired green brick according to claim 1, characterized in that: The preparation method of the four-branched naphthol phosphate is: The hydroxyl functional group of pentaerythritol and the carboxyl functional group of 2-hydroxy-6-naphthoic acid undergo an esterification reaction to generate a tetra-branched naphthol monomer; The tetra-branched naphthol monomer is catalyzed by an organic base catalyst to undergo an esterification reaction with phosphorus oxychloride, and then water is added for hydrolysis to generate a tetra-branched naphthol phosphate.

4. The waste slag soil solidified unfired green brick according to claim 2 or 3, characterized in that: The organic base catalyst is one of triethylamine, pyridine and tetramethylethylenediamine.

5. The waste slag soil solidified unfired green brick according to claim 1, characterized in that: The formula of the curing agent is: 5-10 parts by weight of a special chemical soil curing agent, 25-35 parts by weight of quicklime and 120-125 parts by weight of cement.

6. The waste slag soil solidified unfired green brick according to claim 1, characterized in that: The powder strengthener is starch or polyvinyl alcohol.

7. The waste slag solidified unfired green brick according to any one of claims 1 to 3, characterized in that: The preparation method of the waste slag soil solidified unfired green brick is as follows: Step 1: Pretreatment of waste soil: crush waste soil with a water content of less than 60% into 3-7 mm soil using a gear clay crusher for later use; Step 2, according to the formula of waste slag soil solidified unfired green bricks, polypropylene fiber, chemical special soil solidifier, quicklime, cement, starch and hyperbranched naphthalene water reducer are evenly mixed with waste slag soil, water is added and stirred, and after stirring evenly, the mixture is placed in a mold and pressed, and formed by static pressing for 8-12s at a pressure of 15-25MPa, and steam-cured at 70-90°C for 20-30h or naturally cured at 15-25°C for 25-30 days to obtain waste slag soil solidified unfired green bricks.

8. The waste slag soil solidified unfired green brick according to any one of claims 1 to 3, characterized in that: The compressive strength of the waste slag soil solidified unfired bricks is >18MPa.

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