Sand washing sludge non-burning brick and preparation process thereof

Abstract

The application relates to the field of baking-free bricks, and particularly discloses a sand washing sludge baking-free brick and a preparation process thereof, wherein the sand washing sludge baking-free brick comprises the following raw materials in parts by weight: sand washing sludge 500-550 parts; cement 80-150 parts; stone powder 280-320 parts; quicklime 20-50 parts; solidifying agent 30-50 parts; modified straw fiber 140-200 parts; binder 50-100 parts; water reducing agent 5-20 parts; early strength agent 10-20 parts; and water 3-11 parts; and the modified straw fiber is silane and acrylate compound modified straw fiber. The sand washing sludge baking-free brick prepared by the application has the highest compressive strength of 42.0 MPa, the highest flexural strength of 7.73 MPa, the lowest water absorption of 2.39%, and the lowest bulk density of 1.51 kg / m 3 , and the mechanical properties of the sand washing sludge baking-free brick are improved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of baking-free bricks, in particular to a sand washing sludge baking-free brick and a preparation process thereof. BACKGROUND

[0002] There are many types of building bricks, which can be divided into baking-free bricks and baking bricks according to whether they are baked. Compared with baking bricks, baking-free bricks are a new type of wall material, which uses industrial waste residue as raw material, does not need to be baked and steamed, and has lower production cost than baking bricks. The baking-free bricks have large amount of residue, and have outstanding social and environmental benefits. In addition, the baking-free bricks have neat corners, standard size, large compactness, small water absorption and good durability. Overall, the product quality and comprehensive performance of the baking-free bricks are not inferior to those of the baking bricks.

[0003] The baking-free bricks have wide raw material sources, and have the characteristics of baking-free and steaming-free, which can effectively save resources, reduce energy consumption and absorb solid waste, and are widely used in the wall material building industry.

[0004] Sand washing sludge refers to sludge generated from casting, metallurgy or other industrial production. The large amount of accumulated sand washing sludge seriously pollutes the environment. Therefore, in order to improve the problem of environmental pollution caused by the large amount of accumulated sand washing sludge, it is found that the sand washing sludge contains a large amount of sand, scrap iron and other impurities, and the sand washing sludge can be used as a main raw material to make baking-free bricks, which can solve the problem of environmental pollution and achieve the purpose of waste utilization. However, in the related technology, the sand washing sludge baking-free bricks prepared by selecting the sand washing sludge as the main raw material have low mechanical properties, which cannot meet the actual use requirements. SUMMARY

[0005] In order to improve the mechanical properties of the sand washing sludge baking-free bricks, the application provides a sand washing sludge baking-free brick and a preparation process thereof.

[0006] In a first aspect, the application provides a sand washing sludge baking-free brick, which adopts the following technical scheme:

[0007] A sand washing sludge baking-free brick comprises the following raw materials by weight: 500-550 parts of sand washing sludge, 80-150 parts of cement, 280-320 parts of stone powder, 20-50 parts of quicklime, 30-50 parts of curing agent, 140-200 parts of modified straw fiber, 50-100 parts of binder, 5-20 parts of water reducing agent, 10-20 parts of early strength agent, and 3-11 parts of water.

[0008] The modified straw fiber is a silane and acrylate compound modified straw fiber.

[0009] The sand washing sludge non-burned brick of the application can select 500-550 parts of sand washing sludge, 80-150 parts of cement, 280-320 parts of stone powder, 20-50 parts of quicklime, 30-50 parts of solidifying agent, 140-200 parts of modified straw fiber, 50-100 parts of binder, 5-20 parts by weight of water reducing agent, 10-20 parts by weight of early strength agent, and 3-11 parts of water. The sand washing sludge raw material can select any value within the respective range.

[0010] By adopting the above technical scheme, the sand washing sludge has high mud content and fine sand particles. When the non-burned brick is prepared, the sludge can fill the voids of the sand and tightly accumulate with the sand. Moreover, the sand washing sludge can cement the particles of other raw materials together, thereby improving the compressive strength, flexural strength and softening coefficient of the non-burned brick, which is an excellent matrix material for the non-burned brick. The addition of cement can prevent the non-burned brick from cracking after being soaked in water and improve the strength and water resistance of the non-burned brick. The addition of stone powder and quicklime can increase the adhesion of the non-burned brick. The addition of the solidifying agent can form a film structure between the raw materials, improve the wrapping polymerization and elastic modulus between the raw materials, and enhance the mechanical properties of the non-burned brick. The addition of the binder can increase the thermal conductivity and adhesion of the non-burned brick and improve the stability. The addition of the water reducing agent can disperse the non-burned brick raw materials, enhance the fluidity, improve the workability, reduce the water consumption, and reduce the water-cement ratio, thereby improving the strength of the brick body. The addition of the early strength agent can form complex compounds that can promote the hydration and crystallization of C3S and GaS, accelerate the dissolution of the cement components, promote the hydration reaction, and ultimately improve the mechanical properties of the non-burned brick. The addition of water can promote the mixing of the sand washing sludge non-burned brick raw materials.

[0011] The addition of the modified straw fiber can help to store the water during mixing due to the porous structure of the straw fiber and its excellent hydrophilicity, so that the hydration reaction process can be fully carried out. The stored water can also optimize the humidity index of the non-burned brick and play an internal curing function. On the other hand, the incorporation of the straw fiber can increase the continuity of the matrix, improve the pore structure and inhibit the growth of cracks, thereby improving the mechanical properties of the matrix.

[0012] The C=C double bond in the acrylate and the silane coupling agent undergo addition reaction, the group in the silane coupling agent is introduced into the acrylate polymer molecular chain, the crosslinking between the acrylate and the silane coupling agent is increased, a macromolecular chain is connected into a network structure, there are a large number of hydroxyl groups on the surface of the straw fiber, the silane coupling agent can react with the hydroxyl groups, a "bridge" is formed between the fiber and the acrylate emulsion, is attached to the surface of the straw fiber, increases the crosslinking network thereof, improves the compatibility of the two, also plays a role in preventing the agglomeration of the straw fiber, improves the dispersibility thereof, and promotes the adhesion of the silane and the acrylate composite modified straw fiber; and thus the mechanical properties of the non-burning brick are enhanced.

[0013] As preferred: the modified straw fiber is prepared by the following steps:

[0014] Step S1: 0.5-1.2 kg of silane coupling agent, 3-4 kg of monomer, 0.5-1.7 kg of emulsifier are stirred at 30-50℃ under 1000-1500 r / min to form a prepolymer;

[0015] Step S2: 1-1.5 kg of water and 0.1-0.3 kg of buffer NaHCO3 are added to the prepolymer prepared in step S1 and stirred, the temperature is increased to 60-80℃, 0.4-0.5 kg of initiator is added, and the reaction is carried out for 1-3 h, the emulsion pH is adjusted to 8-9, and a silane and acrylate composite emulsion is obtained;

[0016] Step S3: 3-5 kg of straw fiber is crushed, dried, treated with alkali and then dried, and then added to the silane and acrylate composite emulsion prepared in step S2, and stirred at 30-50℃, to obtain a silane and acrylate composite modified straw fiber.

[0017] Through the above technical solution, first, a seed is formed by pre-polymerization of the silane coupling agent, the monomer and the emulsifier, water and the buffer are added, and the initiator is added at 60-80℃ to cause self-crosslinking to obtain a silane and acrylate composite emulsion; the straw fiber is first treated with an alkaline solution to remove substances such as hemicellulose, lignin and pectin on the surface of the straw fiber, change the roughness of the fiber surface, and enhance the interface bonding capacity of the fiber and the polymer; the straw fiber and the silane and acrylate composite emulsion are fully fused at 30-50℃, the coupling agent and the straw fiber form a chemical bond to improve the interface compatibility between the straw fiber and the emulsion, thereby increasing the crosslinking density of the straw fiber in the washing sand sludge non-burning brick raw material system, and further improving the mechanical properties of the washing sand sludge non-burning brick.

[0018] As preferred: the emulsifier is a mixture of allyloxy hydroxypropyl sulfonate sodium and alkyl glycoside.

[0019] By the above technical scheme, when the two emulsifiers are used in combination, the reaction type allyloxy hydroxypropyl sulfonate sodium forms a negative electron layer, the hydrophilic group on the alkyl glycoside forms a hydrogen bond, and the molecules of the two emulsifiers are alternately adsorbed on the surface of the latex particles to form a stable structure, so that the stability of the polymer emulsion and the stability of the silane and acrylate modified straw fiber are improved, and the mechanical properties of the sand washing sludge non-burning brick are improved.

[0020] Preferably, the weight ratio of the allyloxy hydroxypropyl sulfonate sodium and the alkyl glycoside is (0.7-1.2):1.

[0021] By the above technical scheme, the weight ratio of the allyloxy hydroxypropyl sulfonate sodium and the alkyl glycoside is controlled to be (0.7-1.2):1, which can further improve the mechanical properties of the sand washing sludge non-burning brick.

[0022] Preferably, the weight ratio of the modified straw fiber and the cement is (1.5-1.7):1.

[0023] By the above technical scheme, the weight ratio of the modified straw fiber and the cement is controlled to be (1.5-1.7):1, the silane coupling agent on the surface of the modified straw fiber forms silicon hydroxyl after hydrolysis, which is condensed with the hydroxyl generated on the surface of the cement and its hydration product to form a covalent bond between them, thereby connecting the organic polymer and the hydration product, increasing the cross-linking network between the straw fiber and the cement, and further improving the mechanical properties of the non-burning brick.

[0024] Preferably, the ratio of the water reducing agent dosage to the total weight percentage of all raw materials to the water content of the sand washing sludge is 0.35-1.5wt%:10-30%.

[0025] By the above technical scheme, the ratio of the water reducing agent dosage to the total weight percentage of all raw materials to the water content of the sand washing sludge is controlled to be 0.35-1.5wt%:10-30%, which can further adjust the water content in the raw materials of the non-burning brick, make the whole system under a suitable water content, improve the workability of the raw materials, and further improve the mechanical properties of the sand washing sludge.

[0026] Preferably, the length of the straw fiber is 4-10mm.

[0027] By the above technical scheme, the length of the straw fiber is controlled to be 4-10mm, which can effectively fill the pores of the sand washing sludge non-burning brick, make the internal structure of the sand washing sludge non-burning brick more compact, and thus improve the mechanical properties of the sand washing sludge non-burning brick.

[0028] Preferably, the sand washing sludge non-burning brick raw material further includes 10-50 parts by weight of a mixture of maleic anhydride grafted polypropylene and polydimethylsiloxane.

[0029] By the technical scheme, the sand washing sludge non-burning brick raw material further comprises a maleic anhydride grafted polypropylene and a polydimethylsiloxane mixture, the maleic anhydride grafted polypropylene can enhance the dispersibility of the raw material, the surface tension of the polydimethylsiloxane is low, the sand washing sludge non-burning brick raw material is better dispersed, and a large amount of bubbles generated in the stirring process system can be eliminated, the use of the two in combination can improve the fluidity of the non-burning brick raw material, the density of the system is improved, and the mechanical properties of the non-burning brick are further improved.

[0030] Preferably, the weight ratio of the maleic anhydride grafted polypropylene and the polydimethylsiloxane is (1-2):1.

[0031] By the technical scheme, the weight ratio of the maleic anhydride grafted polypropylene and the polydimethylsiloxane is controlled to be (1-2):1, and the mechanical properties of the sand washing sludge non-burning brick can be further improved.

[0032] In a second aspect, the application provides a preparation process of the sand washing sludge non-burning brick.

[0033] The preparation process of the sand washing sludge non-burning brick comprises the following operation steps: first, plant straw is crushed and modified to obtain modified straw fiber pre-material; then, each component raw material is weighed according to the raw material composition, the stone powder, the cement and the quicklime are mixed and then added to the sand washing sludge, water is added and stirred, and then the modified straw fiber pre-material is added and stirred; then, the curing agent and the binder and the remaining raw materials are added and stirred, and then the sand washing sludge non-burning brick is obtained through the steps of injection molding, standing, pressing forming, demolding and natural curing.

[0034] In summary, the application has at least one of the following beneficial technical effects:

[0035] (1) In the application, the modified straw fiber is prepared into silane and acrylate composite modified straw fiber by adjusting the types and amounts of each raw material, and the compressive strength and the flexural strength of the sand washing sludge non-burning brick prepared by the method are respectively up to 42.0 MPa and 7.73 MPa, and the water absorption and the bulk density are respectively as low as 2.39% and 1.51 kg / m 3 , and the mechanical properties are good.

[0036] (2) In the application, the weight ratio of the modified straw fiber and the cement is controlled, the crosslinking network between the straw fiber and the cement is increased, the compressive strength and the flexural strength of the sand washing sludge non-burning brick prepared by the method are respectively 32.2 MPa and 6.37 MPa, and the water absorption and the bulk density are respectively 4.99% and 1.63 kg / m 3 , and the mechanical properties of the sand washing sludge non-burning brick are improved.

[0037] (3) The application improves the density of the sand washing sludge non-burned brick system by controlling the weight ratio of maleic anhydride grafted polypropylene and polydimethylsiloxane, so that the compressive strength and the flexural strength of the prepared sand washing sludge non-burned brick are 35.7 MPa and 6.86 MPa respectively, and the water absorption and the bulk density are 4.04% and 1.58 kg / m 3 , and the mechanical properties of the sand washing sludge non-burned brick are further improved.

[0038] (4) The application improves the stability of the silane and acrylate composite modified straw fiber by controlling the weight ratio of sodium allyloxy hydroxypropyl sulfonate and alkyl glycoside, so that the compressive strength and the flexural strength of the prepared sand washing sludge non-burned brick are 42.0 MPa and 7.73 MPa respectively, and the water absorption and the bulk density are 2.39% and 1.51 kg / m 3 , and the mechanical properties of the sand washing sludge non-burned brick are further improved. DETAILED DESCRIPTION

[0039] The application will be further described in detail below in combination with specific embodiments.

[0040] The following raw materials in the application are all commercially available products, and are disclosed to fully understand the raw materials of the application, and should not be understood as limiting the source of the raw materials. Specifically:

[0041] The silane coupling agent is selected from γ-glycidyl ether propyl trimethoxysilane with a content of 98%; the emulsifier is selected from sodium allyloxy hydroxypropyl sulfonate with an effective ingredient of 99%; the alkyl glycoside has an effective ingredient of 99%; the monomer is selected from methyl methacrylate with a content of 99.9%; the initiator is selected from potassium persulfate with a content of 99%; the curing agent is selected from silicate with a content of 99%; the adhesive is selected from epoxy resin with a viscosity of 500-900 (mPas) and a solid content of 99%; and the early strength agent is selected from triethanolamine of industrial grade with a content of 99%.

[0042] The following is a preparation example of the modified straw fiber

[0043] Preparation Example 1

[0044] The modified straw fiber of Preparation Example 1 is prepared by the following operation steps:

[0045] Step S1: 0.5 kg of γ-glycidyl ether propyl trimethoxysilane (silane coupling agent), 3.5 kg of monomer, and 0.5 kg of sodium allyloxy hydroxypropyl sulfonate (emulsifier) are stirred at 40°C and 1250 r / min for 30 min to form a prepolymer;

[0046] Step S2: 1.25 kg of water and 0.2 kg of buffer NaHCO3 were added into the prepolymer prepared in step S1 and stirred for 10 min, and then the temperature was raised to 70℃, 0.45 kg of potassium persulfate (initiator) was added, and the reaction was carried out for 2 h, and then the pH of the emulsion was adjusted to 8, to obtain a silane-acrylate composite emulsion;

[0047] Step S3: 4 kg of straw fiber was crushed to an average size of 7 mm, dried for 10 h, and then added into the NaOH solution for treatment for 1.5 h, and then dried, and then added into the silane-acrylate composite emulsion prepared in step S2, and then heated to 40℃ and stirred for 5 h, to obtain the silane-acrylate composite modified straw fiber, and the specific amounts of raw materials are shown in Table 1.

[0048] Preparation Example 2-3

[0049] The operation steps of the modified straw fiber of Preparation Example 2-3 are the same as those of Preparation Example 1, except that the amount of the silane coupling agent, i.e., γ-glycidoxypropyltrimethoxysilane, is different, and the amounts of the other raw materials are the same as those of Preparation Example 1, and the specific amounts are shown in Table 1.

[0050] Table 1 Raw material table of modified straw fiber of Preparation Examples 1-3 (kg)

[0051]

[0052] Preparation Example 4-5

[0053] The operation steps of the modified straw fiber of Preparation Example 4-5 are the same as those of Preparation Example 3, except that the amount of the emulsifier, i.e., allyloxy hydroxypropyl sulfonate sodium, is different, and the amounts of the other raw materials are the same as those of Preparation Example 3, and the specific amounts are shown in Table 2.

[0054] Preparation Example 6-10

[0055] The operation steps of the modified straw fiber of Preparation Example 6-10 are the same as those of Preparation Example 5, except that the amount and type of the emulsifier are different, i.e., the emulsifier is a mixture of allyloxy hydroxypropyl sulfonate sodium and alkyl glycoside, and the amounts of the other raw materials are the same as those of Preparation Example 5, and the specific amounts are shown in Table 2.

[0056] Table 2 Raw material table of modified straw fiber of Preparation Examples 4-10 (kg)

[0057]

[0058] Example 1

[0059] The sand washing sludge non-fired brick of Example 1 was prepared by the following preparation process:

[0060] After 300 kg of stone powder, 80 kg of cement, 35 kg of quicklime are mixed uniformly by mechanical stirring, they are added into 525 kg of sand washing sludge with 20 wt% of water content, 7 kg of water is added and stirred to mix uniformly, then the modified straw fiber prepared in Preparation Example 1 is added and stirred to mix uniformly; then 40 kg of silicate (curing agent) and 75 kg of epoxy resin (binder) are added and stirred to mix uniformly, finally 15 kg of triethanolamine (early strength agent) and 13 kg of water reducing agent are added and stirred to mix uniformly, wherein the water reducing agent accounts for 1.02 wt% of the total weight of all raw materials, then the mold is injected, left to stand, pressed to form, demolded, and then cured in a ventilated, cool, and 20±5℃ temperature environment, and the curing is performed for 10 days with water spraying twice a day, to obtain the sand washing sludge baking-free brick.

[0061] Example 2-3

[0062] The preparation process of the sand washing sludge baking-free brick of Example 2-3 is the same as that of Example 1, except that the amount of cement in the raw materials is different, and the amounts of the remaining raw materials are the same as those of Example 1, which are specifically shown in Table 3.

[0063] Example 4-7

[0064] The preparation process of the sand washing sludge baking-free brick of Example 4-7 is the same as that of Example 3, except that the amount of modified straw fiber in the raw materials is different, and the amounts of the remaining raw materials are the same as those of Example 3, which are specifically shown in Table 3.

[0065] Table 3 Amounts of raw materials (kg), water content of sand washing sludge (%) and weight percentage (wt%) of water reducing agent for the sand washing sludge baking-free brick of Examples 2-7

[0066]

[0067] Example 8-12

[0068] The preparation process of the sand washing sludge baking-free brick of Example 8-12 is the same as that of Example 5, except that acid anhydride grafted polypropylene and polydimethylsiloxane mixture are added to the raw materials, and the amounts are different, and the amounts of the remaining raw materials are the same as those of Example 5, which are specifically shown in Table 4.

[0069] Table 4 Amounts of raw materials (kg), water content of sand washing sludge (%) and weight percentage (wt%) of water reducing agent for the sand washing sludge baking-free brick of Examples 8-12

[0070]

[0071]

[0072] Example 13-21

[0073] The preparation process of the sand washing sludge baking-free brick of examples 13-21 is the same as example 10, except that the modified straw fiber in the raw material is replaced by the modified straw fiber prepared in preparation example 2-10, and the amount of the remaining raw materials is the same as that of example 10.

[0074] Comparative example 1

[0075] The preparation process of the sand washing sludge baking-free brick of comparative example 1 is the same as example 1, except that the modified straw fiber in the raw material is replaced by an equal amount of unmodified straw fiber, and the amount of the remaining raw materials is the same as that of example 1.

[0076] Comparative example 2

[0077] The preparation process of the sand washing sludge baking-free brick of comparative example 2 is the same as example 1, except that the modified straw fiber in the raw material is replaced by an equal amount of silane-modified straw fiber, and the amount of the remaining raw materials is the same as that of example 1, wherein the silane-modified straw fiber is obtained by the following steps: 4 kg of straw fiber is crushed to an average size of 7 mm, dried for 10 h, then added to a NaOH solution for 1.5 h, then dried, added to a silane coupling agent, and heated to 40℃ for 5 h with stirring, to obtain the silane-modified straw fiber.

[0078] Comparative example 3

[0079] The preparation process of the sand washing sludge baking-free brick of comparative example 3 is the same as example 1, except that the modified straw fiber in the raw material is replaced by an equal amount of acrylic acid-modified straw fiber, and the amount of the remaining raw materials is the same as that of example 1, and the specific method is that no silane coupling agent is added in the preparation of the modified straw fiber, and the acrylic acid-modified straw fiber is obtained.

[0080] Performance detection

[0081] The performance of the sand washing sludge baking-free bricks obtained in different examples 1-21 and comparative examples 1-3 was detected according to the JC 422-1991 detection standard, and the detection results are shown in Table 5.

[0082] Table 5 Performance detection results of sand washing sludge baking-free bricks prepared in different examples and comparative examples

[0083]

[0084]

[0085] The detection results in Table 5 show that the compressive strength and the bending strength of the sand washing sludge baking-free bricks obtained in the present application are the highest, which are 42.0 MPa and 7.73 MPa, respectively, and the water absorption and the bulk density are the lowest, which are 2.39% and 1.51 kg / m 3 , respectively, which improves the mechanical properties of the sand washing sludge baking-free bricks.

[0086] The compressive strength and the flexural strength of the sand washing sludge baking-free brick obtained in Examples 4-6 are 31.2-32.2 MPa and 6.23-6.37 MPa, respectively, which are higher than those of Examples 1 and 7; the water absorption and the bulk density are 4.99-5.25% and 1.63-1.631 kg / m 3 , respectively, which are lower than those of Examples 1 and 7, indicating that when the weight ratio of the modified straw fiber and the cement is controlled to be (1.5-2):1, the mechanical properties of the baking-free brick are improved. This may be related to the increase in the crosslinking network between the straw fiber and the cement by controlling the weight ratio of the modified straw fiber and the cement.

[0087] The compressive strength and the flexural strength of the sand washing sludge baking-free brick obtained in Examples 9-11 are 34.8-35.7 MPa and 6.73-6.86 MPa, respectively, which are higher than those of Examples 8 and 12; the water absorption and the bulk density are 4.04-4.31% and 1.58-1.591 kg / m 3 , respectively, which are lower than those of Examples 8 and 12, indicating that when the maleic anhydride grafted polypropylene and the polydimethylsiloxane mixture are added to the raw materials, the performance of the baking-free brick is improved, and when the weight ratio of the maleic anhydride grafted polypropylene and the polydimethylsiloxane is controlled to be (0.7-1.2):1, the mechanical properties of the baking-free brick are further improved. This may be related to the increase in the density of the sand washing sludge baking-free brick system by controlling the weight ratio of the maleic anhydride grafted polypropylene and the polydimethylsiloxane.

[0088] The compressive strength and the flexural strength of the sand washing sludge baking-free brick obtained in Example 17 are 40.1 MPa and 7.47 MPa, respectively, which are higher than those of Examples 10 and 13-16; the water absorption and the bulk density are 2.88% and 1.531 kg / m 3 , respectively, which are lower than those of Examples 10 and 13-16, indicating that when the emulsifier allyloxyhydroxypropyl sulfonate and the alkyl glycoside are used in combination, the mechanical properties of the baking-free brick are improved. This may be related to the improvement in the stability of the polymer emulsion and the stability of the silane and acrylate composite modified straw fiber by controlling the weight ratio of the allyloxyhydroxypropyl sulfonate and the alkyl glycoside.

[0089] The compressive strength and the flexural strength of the sand washing sludge baking-free brick obtained in Examples 18-20 are 40.2-42.0 MPa and 7.48-7.73 MPa, respectively, which are higher than those of Examples 17 and 21; the water absorption and the bulk density are 2.39-2.86% and 1.51-1.53 kg / m 3, which are lower than those of Example 17 and Example 21, indicating that the weight ratio of sodium allyloxyhydroxypropyl sulfonate to alkyl glycoside is more appropriate when controlled to be (0.7-1.2):1, thereby improving the mechanical properties of the unfired brick. It is possible that controlling the weight ratio of sodium allyloxyhydroxypropyl sulfonate to alkyl glycoside to be (0.7-1.2):1 can further increase the stability of the polymer emulsion and promote the stability of the silane and acrylate composite modified straw fiber.

[0090] In addition, in combination with the index data of the sand washing sludge unfired brick of Comparative Examples 1-3 and Example 1, it is found that the addition of the silane and acrylate composite modified straw fiber in the sand washing sludge unfired brick raw material of the present application can improve the mechanical properties of the sand washing sludge unfired brick to different degrees.

[0091] The specific embodiments are merely an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, as long as the modifications are within the scope of the claims of the present application.

Claims

1. A sand washing sludge non-fired brick, characterized in that, The raw materials include the following weight parts: 500-550 parts of sand washing sludge; Cement 80-150 parts; stone powder 280-320 parts; quicklime 20-50 parts; Solidifying agent 30-50 parts; Modified straw fiber 140-200 parts; binder 50-100 parts; water reducing agent 5-20 parts; early strength agent 10-20 parts; water 3-11 parts; The modified straw fiber is a silane and acrylate composite modified straw fiber, and the modified straw fiber is prepared by the following steps: Step S1: stirring 0.5-1.2 kg of silane coupling agent, 3-4 kg of methacrylic acid, and 0.5-1.7 kg of emulsifier at 30-50°C and 1000-1500 r / min to form a prepolymer; Step S2: adding 1-1.5 kg of water and 0.1-0.3 kg of buffer NaHCO3 to the prepolymer prepared in step S1 and stirring, heating to 60-80°C, adding 0.4-0.5 kg of initiator, and reacting for 1-3 h to adjust the emulsion pH to 8-9 to obtain a silane and acrylate composite emulsion; Step S3: crushing 3-5 kg of straw fiber, drying, and then alkali treatment and drying, and then adding to the silane and acrylate composite emulsion prepared in step S2, and stirring at 30-50°C to obtain a silane and acrylate composite modified straw fiber; The length of the straw fiber is 4-10 mm; The weight ratio of the modified straw fiber to cement is (1.5-1.7):

1.

2. The sand washed sludge non-burned brick according to claim 1, wherein, The emulsifier is a mixture of allyloxy hydroxypropyl sulfonate sodium and alkyl glycoside.

3. The sand washed sludge non-burnt brick according to claim 2, characterized in that, The weight ratio of the allyloxy hydroxypropyl sulfonate sodium to alkyl glycoside is (0.7-1.2):

1.

4. The sand washed sludge non-burnt brick according to claim 1, wherein, The water reducing agent is used in an amount of 0.35-1.5wt%:10-30% based on the ratio of the total weight percentage of all raw materials to the water content of the sand washing sludge.

5. The sand washed sludge baking-free brick as claimed in claim 1, wherein, The raw materials of the sand washing sludge non-fired brick further include 10-50 parts by weight of a mixture of maleic anhydride grafted polypropylene and polydimethylsiloxane.

6. The sand washed sludge non-burnt brick according to claim 5, wherein, The weight ratio of the maleic anhydride grafted polypropylene to polydimethylsiloxane is (1-2):

1.

7. The process for the preparation of sand washed slurry free burning brick as claimed in any one of claims 1 to 6 wherein, First, the plant straw is crushed and modified to obtain modified straw fiber; then the raw materials are weighed according to the raw material composition, the stone powder, cement, and quicklime are mixed and added to the sand washing sludge, water is added and stirred, and then the modified straw fiber is added and stirred; then the solidifying agent, binder, and the remaining raw materials are added and stirred, molded, placed, pressed, demolded, and naturally cured to obtain the sand washing sludge non-fired brick.

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