Preparation method of lightweight board

Abstract

The preparation method of the light board comprises the following steps: S1, stirring and wetting; s2, dehydration treatment; s3, extruding and draining; s4, repeating the steps S2 and S3 until no excessive water is discharged and overflows; s5, mixing the materials; s6, performing desizing treatment; s7, extruding and discharging pulp; s8, the step S6 and the step S7 are repeated until no redundant slurry is discharged and overflows, and a plate blank is obtained; and S9, forming and curing are conducted, and the light board is obtained. By adopting the method, the agriculture and forestry residues are only adhered with necessary moisture in a mode of wetting in advance and fully draining water, so that the influence on the moisture content of the slurry after the agriculture and forestry residues are mixed with the inorganic adhesive slurry in the later period can be reduced; by means of the mode of discharging the adhesive slurry, the surplus slurry is discharged while it is guaranteed that the agricultural and forestry residues are fully wrapped with the slurry, the weight of the plate is reduced, and the use amount of the adhesive slurry is also reduced. Therefore, the mixing amount of the agriculture and forestry residues is increased, the use amount of the inorganic adhesive material is reduced, and the quality stability and the lightweight characteristic of the product are ensured.

Description

Technical Field

[0001] The invention relates to the application field of agricultural and forestry residues in building materials, and in particular to a method for preparing a lightweight board, specifically a method for preparing a lightweight board blank by combining agricultural and forestry residues and an inorganic adhesive material. Background Art

[0002] Agricultural and forestry residues are an important biomass resource. They are produced from the harvesting and processing of agricultural and forestry crops. Common ones include straw, wood and bamboo processing residues, and forest felling residues. As straw is a natural carbon-fixing and renewable material, the decorative board market has great development potential. Crop straw is the stem of herbaceous plants. Since crops are usually annual herbaceous plants, their circulation speed is much faster than that of wood. Straw board is an excellent ecological material in terms of performance and molding process, and can replace wood materials as the main material for interior decoration.

[0003] At present, we are vigorously promoting the comprehensive utilization of straw and driving the quality and efficiency improvement of the straw comprehensive utilization industry.

[0004] At present, straw boards for interior decoration have problems such as poor physical strength, poor waterproofness, poor bonding, and high glue consumption. Among them, the formaldehyde release problem of boards is the most prominent. Aldehyde resin adhesives are widely used due to their advantages such as good bonding and low cost, but the materials contain too much free formaldehyde. Therefore, in the prior art, the main problems of boards made of agricultural and forestry residues are as follows:

[0005] (1) Straw made with aldehyde-containing adhesives poses a risk of formaldehyde release;

[0006] (2) Formaldehyde-free MDI glue is expensive, difficult to demold, and has the risk of releasing other potential volatile toxic gases besides formaldehyde;

[0007] (3) Most inorganic materials used as adhesives to make boards will increase the weight of the boards, affecting the convenience of construction. Summary of the invention

[0008] The main purpose of the present invention is to provide a method for preparing a lightweight plate material, aiming to solve the above technical problems.

[0009] To achieve the above object, the present invention provides a method for preparing a lightweight plate, comprising the following steps:

[0010] S1. Stirring and moistening: Pour the agricultural and forestry residues into a stirring container, add water and stir to moisten;

[0011] S2. Dehydration treatment: After the agricultural and forestry residues are fully moistened, they are dehydrated by centrifugal rotation;

[0012] S3, squeezing and draining: squeezing the agricultural and forestry residues dehydrated in step S2 to further drain the residual water in the agricultural and forestry residues;

[0013] S4, repeat steps S2 and S3 until no excess water overflows;

[0014] S5, mixing: mixing the inorganic adhesive material, auxiliary materials and water to obtain an adhesive slurry; mixing the prepared adhesive slurry with the wetted, dehydrated and drained agricultural and forestry residues obtained in step S4 and stirring them to obtain a mixture;

[0015] S6, desizing treatment: desizing the mixed material by centrifugal rotation to obtain a desizing material;

[0016] S7, extrusion and slurry removal: extruding the desizing material in step S6 to further discharge excess adhesive slurry;

[0017] S8, repeating steps S6 and S7 until no more slurry overflows, thereby obtaining a sheet blank;

[0018] S9, forming and curing: pouring the board blank obtained in step S8 into a board mold for compression molding and curing; obtaining a lightweight board.

[0019] Preferably, the water discharged during the dehydration treatment in step S2 and the water overflowed during the squeezing and drainage in step S3 are collected; and the collected water is used to moisten the agricultural and forestry residues in step S1.

[0020] Preferably, the adhesive slurry discharged during the desizing process in step S6 and the adhesive slurry overflowed during the extrusion desizing process in step S3 are collected; and the collected adhesive slurry is used in step S5 to mix with agricultural and forestry residues.

[0021] Preferably, the agricultural and forestry residues are one or more of rice straw, wheat straw, corn straw, and coconut shreds.

[0022] Preferably, in step S5, the auxiliary material is one or more of fly ash, stone powder, and steel slag powder.

[0023] Preferably, in step S2 and step S6, a spin-drying drum is used for dehydration and desizing, and a plurality of through holes are evenly distributed on the wall and bottom of the spin-drying drum.

[0024] Preferably, the spin-drying drum is equipped with a pressure cover; when squeezing and draining water is performed in step S3, the pressure cover is placed in the spin-drying drum and the top cover is squeezed downwards, so that the residual moisture in the agricultural and forestry residues is discharged from the through holes of the spin-drying drum; when squeezing and draining pulp is performed in step S7, the pressure cover is placed in the spin-drying drum and the top cover is squeezed downwards, so that the excess adhesive pulp is discharged from the through holes of the spin-drying drum.

[0025] Preferably, a shell is arranged outside the drying drum, and the lower end of the shell is arranged in a funnel shape to form a discharge port.

[0026] Preferably, the inorganic adhesive material includes a silicate inorganic adhesive, a magnesium oxide inorganic adhesive, a sulfate inorganic adhesive or a phosphate inorganic adhesive.

[0027] Preferably, the inorganic adhesive material is magnesium oxychloride cement or gypsum.

[0028] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0029] (1) In the present invention, by wetting in advance and draining the water sufficiently, the agricultural and forestry residues are allowed to adhere only to necessary water, which can reduce the influence of the agricultural and forestry residues on the moisture content of the slurry after mixing with the inorganic adhesive slurry in the later stage, and reduce the moisture content of the board blank; finally, the influence of the agricultural and forestry residues on the stability of the adhesive slurry system can be reduced to ensure the mechanical properties of the board after forming.

[0030] (2) In the present invention, by discharging the adhesive slurry, the excess slurry is discharged while ensuring that the slurry is fully wrapped around the agricultural and forestry residues, which not only reduces the weight of the board, but also reduces the amount of adhesive slurry. At the same time, it also increases the amount of agricultural and forestry residues in the unit board product.

[0031] (3) In the present invention, the method of pre-wetting and water control can reduce the problem of different water absorption levels caused by the types and quality instability of agricultural and forestry residues, thereby reducing the influence of agricultural and forestry residues on the inorganic adhesive slurry. Therefore, it is only necessary to determine the appropriate ratio of the adhesive slurry, and the amount of the adhesive slurry does not need to be precisely controlled, because the excess slurry will be discharged in time and recycled. By adopting the present invention, the agricultural and forestry residue / adhesive material ratio in the board blank is basically guaranteed, and the stability of the board quality is also guaranteed.

[0032] (4) In the present invention, excess water and excess adhesive slurry can be recycled to reduce water consumption and reduce the consumption of adhesive slurry.

[0033] (5) In the present invention, a silicate inorganic adhesive, a magnesium oxide inorganic adhesive, a sulfate inorganic adhesive or a phosphate inorganic adhesive is used as the inorganic adhesive material, and the prepared board is formaldehyde-free, thereby improving the safety of the board. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 This is a flow chart of a method for preparing a lightweight plate proposed by the present invention;

[0036] Figure 2 It is a schematic diagram of the spin drying drum, top cover and shell body in the present invention when they are matched.

[0037] Description of the accompanying drawings: 1. spin-drying drum; 1a. through hole; 2. top cover; 3. shell; 3a. discharge port. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0040] Combination Figure 1 As shown, a method for preparing a lightweight plate comprises the following steps:

[0041] S1. Stirring and moistening: Pour the agricultural and forestry residues into a stirring container, add water and stir to moisten;

[0042] S2. Dehydration treatment: After the agricultural and forestry residues are fully moistened, they are dehydrated by centrifugal rotation;

[0043] S3, squeezing and draining: squeezing the agricultural and forestry residues dehydrated in step S2 to further drain the residual water in the agricultural and forestry residues;

[0044] S4, repeat steps S2 and S3 until no excess water overflows;

[0045] S5, mixing: mixing the inorganic adhesive material, auxiliary materials and water to obtain an adhesive slurry; mixing the prepared adhesive slurry with the wetted, dehydrated and drained agricultural and forestry residues obtained in step S4 and stirring them to obtain a mixture;

[0046] S6, desizing treatment: desizing the mixed material by centrifugal rotation to obtain a desizing material;

[0047] S7, extrusion and slurry removal: extruding the desizing material in step S6 to further discharge excess adhesive slurry;

[0048] S8, repeating steps S6 and S7 until no more slurry overflows, thereby obtaining a sheet blank;

[0049] S9, forming and curing: pouring the board blank obtained in step S8 into a board mold for compression molding and curing; obtaining a lightweight board.

[0050] Furthermore, the water discharged during the dehydration process in step S2 and the water overflowed during the squeezing and drainage process in step S3 are collected; and the collected water is used to moisten the agricultural and forestry residues in step S1. The adhesive slurry discharged during the desizing process in step S6 and the adhesive slurry overflowed during the squeezing and drainage process in step S3 are collected; and the collected adhesive slurry is used to mix with the agricultural and forestry residues in step S5.

[0051] In this embodiment, the agricultural and forestry residues are one or more of rice straw, wheat straw, corn straw, and coconut shreds. The auxiliary materials are one or more of fly ash, stone powder, and steel slag powder.

[0052] Combination Figure 2 As shown, in step S2 and step S6, a spin-drying drum 1 is used for dehydration and desizing, and a plurality of through holes 1a are evenly distributed on the barrel wall and barrel bottom of the spin-drying drum 1. Furthermore, the spin-drying drum 1 is equipped with a gland 2; when squeezing and draining water is performed in step S3, the gland 2 is placed in the spin-drying drum 1 and the top cover 2 is squeezed downward, so that the residual water in the agricultural and forestry residues is discharged from the through holes 1a of the spin-drying drum 1; when squeezing and draining pulp is performed in step S7, the gland 2 is placed in the spin-drying drum 1 and the top cover 2 is squeezed downward, so that the excess adhesive pulp is discharged from the through holes 1a of the spin-drying drum 1. A boss is provided on the top of the gland 2 to facilitate clamping with the clamping device on the press. The spin-drying drum 1 is used for dehydration and desizing by centrifugal rotation, and its principle is similar to the spin-drying structure on the washing machine, which will not be described in detail here.

[0053] Combination Figure 2As shown, a shell 3 is provided outside the spin-drying drum 1, and the lower end of the shell 3 is configured to be funnel-shaped and form a discharge port 3a. The shell 3 is used to collect the water discharged during the dehydration process in step S2, and the water overflowed during the squeezing and draining process in step S3, and to collect the adhesive slurry discharged during the desizing process in step S6, and the adhesive slurry overflowed during the squeezing and draining process in step S3.

[0054] In this embodiment, the inorganic adhesive material includes silicate inorganic adhesive, magnesium oxide inorganic adhesive, sulfate inorganic adhesive or phosphate inorganic adhesive. Specifically, the inorganic adhesive material is magnesium oxychloride cement or gypsum.

[0055] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a lightweight plate, characterized in that: The steps include: S1. Stirring and moistening: Pour the agricultural and forestry residues into a stirring container, add water and stir to moisten; S2. Dehydration treatment: After the agricultural and forestry residues are fully moistened, they are dehydrated by centrifugal rotation; S3, squeezing and draining: squeezing the agricultural and forestry residues dehydrated in step S2 to further drain the residual water in the agricultural and forestry residues; S4, repeat steps S2 and S3 until no excess water overflows; S5, mixing: mixing the inorganic adhesive material, auxiliary materials and water to obtain an adhesive slurry; mixing the prepared adhesive slurry with the wetted, dehydrated and drained agricultural and forestry residues obtained in step S4 and stirring them to obtain a mixture; S6, desizing treatment: desizing the mixed material by centrifugal rotation to obtain a desizing material; S7, extrusion and slurry removal: extruding the desizing material in step S6 to further discharge excess adhesive slurry; S8, repeating steps S6 and S7 until no more slurry overflows, thereby obtaining a sheet blank; S9, forming and curing: pouring the board blank obtained in step S8 into a board mold for compression molding and curing; obtaining a lightweight board.

2. A method for preparing a lightweight plate material according to claim 1, characterized in that: The water discharged during the dehydration process in step S2 and the water overflowed during the squeezing and drainage process in step S3 are collected; and the collected water is used to moisten the agricultural and forestry residues in step S1.

3. The method for preparing a lightweight plate material according to claim 1, characterized in that: The adhesive pulp discharged during the desizing process in step S6 and the adhesive pulp overflowed during the extrusion desizing process in step S3 are collected; and the collected adhesive pulp is used in step S5 to mix with agricultural and forestry residues.

4. The method for preparing a lightweight plate material according to claim 1, characterized in that: The agricultural and forestry residues are one or more of rice straw, wheat straw, corn straw and coconut shreds.

5. The method for preparing a lightweight plate material according to claim 1, characterized in that: In step S5, the auxiliary material is one or more of fly ash, stone powder, and steel slag powder.

6. The method for preparing a lightweight plate material according to claim 1, characterized in that: In the step S2 and the step S6, a spin drying drum (1) is used for dehydration and desizing, and a plurality of through holes (1a) are evenly distributed on the barrel wall and the barrel bottom of the spin drying drum (1).

7. A method for preparing a lightweight plate material according to claim 6, characterized in that: The spin-drying drum (1) is equipped with a pressure cover (2); when squeezing and draining water in step S3, the pressure cover (2) is placed in the spin-drying drum (1) and the top cover (2) is pressed downward, so that the residual moisture in the agricultural and forestry residues is discharged from the through hole (1a) of the spin-drying drum (1); when squeezing and draining pulp in step S7, the pressure cover (2) is placed in the spin-drying drum (1) and the top cover (2) is pressed downward, so that the excess adhesive pulp is discharged from the through hole (1a) of the spin-drying drum (1).

8. The method for preparing a lightweight plate material according to claim 7, characterized in that: A shell (3) is arranged outside the drying drum (1), and the lower end of the shell (3) is arranged in a funnel shape and forms a discharge port (3a).

9. The method for preparing a lightweight plate material according to claim 1, characterized in that: The inorganic adhesive material includes a silicate inorganic adhesive, a magnesium oxide inorganic adhesive, a sulfate inorganic adhesive or a phosphate inorganic adhesive.

10. A method for preparing a lightweight plate material according to claim 9, characterized in that: The inorganic adhesive material is magnesium oxychloride cement or gypsum.

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