Modified phosphogypsum paper-surface-free gypsum board and preparation method thereof

Abstract

The invention belongs to the field of plasterboards, particularly discloses a modified phosphogypsum paper-surface-free plasterboard and a preparation method thereof, and belongs to the technical field of plasterboards, and the plasterboard comprises modified phosphogypsum powder, water, an additive and modified glass fibers. The modified glass fiber is prepared by immersing glass fiber into fermentation liquor and then treating to load a functional coating on the surface of the glass fiber, or before immersing the glass fiber into the fermentation liquor, firstly carrying out etching pretreatment on the glass fiber, calcining ardealite and then converting into semi-hydrated gypsum; and fully and uniformly mixing the semi-hydrated gypsum and the biochar to obtain the modified phosphogypsum powder. The glass fibers are modified to enhance the interface bonding with the gypsum, so that the glass fibers have better mechanical properties, and meanwhile, through the synergistic effect of the modified glass fibers and the modified phosphogypsum, the mechanical properties are enhanced, the damp is reduced, and the anti-mildew performance is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of gypsum boards, and particularly relates to a modified phosphogypsum non-paper gypsum board and a preparation method thereof. Background Art

[0002] The surface of the paper-faced gypsum board is relatively rough and the texture is relatively poor, which affects the final decoration effect. Therefore, customers with higher decoration requirements tend to choose non-paper gypsum boards. The non-paper gypsum board made of modified phosphogypsum reduces the raw material cost. However, the non-paper gypsum board is easy to get damp, and its compressive and impact resistance are relatively poor, and it is easy to be damaged during handling or use.

[0003] Adding reinforcing materials such as glass fibers to the gypsum board can significantly improve its compressive and impact resistance. However, glass fibers are prone to agglomeration in the gypsum slurry, resulting in uneven distribution, affecting the reinforcement effect, and the interfacial bonding between the glass fibers and the gypsum matrix is weak, which may lead to low stress transfer efficiency and affect the reinforcement effect. Summary of the Invention

[0004] To solve the above problems, the present invention provides a modified phosphogypsum non-paper gypsum board and a preparation method thereof. By modifying the glass fibers to enhance their interfacial bonding with gypsum, it has good mechanical properties. At the same time, through the synergistic effect of the modified glass fibers and the modified phosphogypsum, while enhancing the mechanical properties, it reduces moisture absorption and has mildew resistance.

[0005] The present invention is achieved through the following technical solutions:

[0006] A modified phosphogypsum non-paper gypsum board, comprising the following raw materials in parts by weight: 80-90 parts of modified phosphogypsum powder, 5-10 parts of glass fibers, 10-20 parts of water, and 1-5 parts of additives;

[0007] Wherein the glass fibers are modified glass fibers, and the glass fibers are immersed in the fermentation broth and then treated so that the surface of the glass fibers is loaded with a functional coating.

[0008] Further, before the glass fibers are immersed in the fermentation broth, the glass fibers are first subjected to etching pretreatment to obtain etched glass fibers, so that the surface of the glass fibers has micron-sized pits, and then the etched glass fibers are immersed in the fermentation broth and treated.

[0009] Further, the etching pretreatment is acid etching, alkali etching or laser etching.

[0010] Further, Aureobasidium pullulans is added to the fermentation broth, and after fermentation, it is dried, and a pullulan functional coating is loaded on the surface of the glass fibers.

[0011] Furthermore, the fermentation conditions in the fermentation broth are as follows: the temperature is 25 - 28 °C, the stirring speed is 100 - 300 rpm, the initial pH is 5.5 - 6.5, and 10 - 20 g of glass fiber is immersed in each liter of the fermentation broth.

[0012] Furthermore, the length of the glass fiber is 3 - 6 mm.

[0013] Furthermore, the preparation method of the modified phosphogypsum powder is as follows: the phosphogypsum is calcined and transformed into hemihydrate gypsum, and the hemihydrate gypsum is fully mixed with biochar to obtain the modified phosphogypsum powder.

[0014] Furthermore, the temperature of the calcination treatment is 120 °C - 180 °C, and the calcination time is 1 - 2 hours.

[0015] Furthermore, the additives include a foaming agent, a flame retardant, and a setting regulator.

[0016] The present invention also provides a preparation method of a modified phosphogypsum plasterboard without paper surface, comprising the following steps:

[0017] Step 1: Mix the prepared modified phosphogypsum powder with water and additives evenly to form a gypsum slurry;

[0018] Step 2: Add the prepared modified glass fiber to the gypsum slurry in batches, and stir evenly at a low speed to obtain a mixed slurry;

[0019] Step 3: Pour the mixed slurry into a mold, scrape it flat, let it solidify, and then dry and demold to obtain the plasterboard.

[0020] The beneficial effects of the present invention are as follows:

[0021] (1) In this application, modified glass fiber is added. First, the glass fiber is etched and then immersed in the fermentation broth. After post-treatment, a pullulan functional coating is formed on the surface of the glass fiber. After the glass fiber is etched, the surface roughness and the density of hydroxyl groups (-OH) on the glass fiber surface can be increased, and the attachment ability of microorganisms and polysaccharides can be enhanced. The hyphae or yeast-like cells of Aureobasidium pullulans will preferentially attach to the etched rough surface. The attached bacteria directly secrete pullulan during the fermentation process and form a uniform viscous film on the surface of the glass fiber;

[0022] (2) Since the hydroxyl groups of pullulan form coordination bonds with calcium ions in gypsum (CaSO4·2H2O), the interfacial compatibility between glass fiber and phosphogypsum is improved, the bonding force between glass fiber and gypsum matrix is enhanced, the risk of fiber pull-out is reduced, the pores between glass fiber and gypsum can also be reduced, cracking caused by stress concentration is prevented, and crack propagation is also inhibited to a certain extent; moreover, the lubricity of pullulan enables the glass fiber to be more evenly dispersed in the gypsum slurry, avoiding agglomeration; in addition, pullulan has moderate hygroscopicity (the water absorption rate is about 10% under equilibrium humidity), which can adjust the local humidity of the gypsum board, reduce the dry shrinkage cracks and moisture-induced deformation of the gypsum board. In addition, pullulan itself has antibacterial properties (especially against molds), which can delay the service life of the gypsum board in a humid environment;

[0023] (3) Modified phosphogypsum powder is prepared from hemihydrate gypsum and biochar. The calcined hemihydrate gypsum has high hydration activity, and the formed dihydrate gypsum crystal structure is dense after hardening, which can improve the compressive and flexural strength of the gypsum board. The porous structure of biochar can adsorb pullulan to form a three-dimensional network of "fiber-polysaccharide-biochar-gypsum", reducing the interfacial porosity; at the same time, the alkaline surface (pH 8-10) of biochar can neutralize the residual acidity of phosphogypsum, while delaying the hydration of gypsum, and synergistically with the water retention of pullulan, reducing the risk of cracking; the oxygen-containing functional groups (such as carboxyl groups and phenolic hydroxyl groups) on the surface of biochar form hydrogen bonds with the hydroxyl groups (-OH) of pullulan, and at the same time coordinate and bind with gypsum through calcium ions, thereby improving the interfacial adhesion between glass fiber and gypsum matrix; in addition, the adsorption of biochar combined with the antibacterial property of pullulan prolongs the durability of the gypsum board in a humid environment;

[0024] In summary, the mechanical properties, antibacterial properties, waterproof properties, etc. of the gypsum board prepared by this method are all improved. Detailed implementation mode

[0025] A modified phosphogypsum non-paper gypsum board comprises the following raw materials in parts by weight: 80-90 parts of modified phosphogypsum powder, 5-10 parts of glass fiber, 10-20 parts of water, and 1-5 parts of additive;

[0026] Wherein the glass fiber is modified glass fiber, and the length of the glass fiber is 3-6 mm. The glass fiber is immersed in the fermentation broth for treatment. Pullulan is added to the fermentation broth. After fermentation, it is washed with deionized water and dried, and a pullulan functional coating is loaded on the surface of the glass fiber. The thickness of the pullulan coating is 1-5 μm. The fermentation conditions in the fermentation broth are: the temperature is 25-28 °C (too high is easy to cause cell autolysis), the stirring speed is 100-300 rpm (to avoid damaging the fiber structure, and stirring is stopped 24 h before fermentation to promote the deposition of polysaccharide on the fiber surface), the initial pH is 5.5-6.5, and 10-20 g of glass fiber is immersed in each liter of fermentation broth.

[0027] Furthermore, the culture medium components in the fermentation broth include conventional components (carbon source, nitrogen source, inorganic salts, phosphate buffer solution), which will not be elaborated. 0.1% non-ionic surfactant can be added to the fermentation broth. The non-ionic surfactant is Tween-80 to avoid the agglomeration of glass fibers. Chloramphenicol (50 μg / mL) for bacteria or Na2SO3 (0.1%) for inhibiting fungal contaminants can also be added to the fermentation broth to avoid contamination by miscellaneous bacteria.

[0028] Furthermore, before immersing the glass fibers in the fermentation broth, the glass fibers are first subjected to etching pretreatment to obtain etched glass fibers, so that the surface of the glass fibers has micron-sized pits. Then the etched glass fibers are immersed in the fermentation broth for post-treatment. The etching pretreatment is acid etching, alkali etching or laser etching. Acid etching is to soak with 10% HCl or H2SO4 for 30 - 60 minutes, and alkali etching is to soak with 5% NaOH for 1 - 2 hours. Micron-sized pits are formed on the surface of the etched fibers, and the specific surface area increases by 50% - 100%, which is beneficial for the attachment of bacteria and polysaccharides.

[0029] Furthermore, the preparation method of the modified phosphogypsum powder is as follows: The phosphogypsum is calcined to be converted into hemihydrate gypsum. The temperature of the calcination treatment is 120°C - 180°C, and the calcination time is 1 - 2 hours. The hemihydrate gypsum and biochar are fully mixed evenly to obtain the modified phosphogypsum powder. The doping amount of biochar is 5% - 20% of the hemihydrate gypsum, and the particle size of the biochar is <50 μm.

[0030] Furthermore, the additives include a foaming agent, a flame retardant, and a setting regulator, all of which are conventional components and will not be elaborated.

[0031] The present invention also provides a preparation method of a modified phosphogypsum gypsum board without paper face, including the following steps:

[0032] Step 1: Mix the prepared modified phosphogypsum powder with water and additives evenly to form a gypsum slurry;

[0033] Step 2: Add the prepared modified glass fibers to the gypsum slurry in batches, and stir evenly at a low speed to obtain a mixed slurry;

[0034] Step 3: Pour the mixed slurry into a mold, scrape it flat, solidify, and then dry and demold to obtain the gypsum board.

[0035] The following further describes the present invention with reference to specific preferred embodiments, but does not limit the protection scope of the present invention accordingly.

[0036] Example 1

[0037] A modified phosphogypsum plasterboard without paper face comprises raw materials in the following parts by weight: 80 - 90 parts of modified phosphogypsum powder, 5 - 10 parts of glass fiber, 10 - 20 parts of water, and 1 - 5 parts of additives;

[0038] Wherein the glass fiber is modified glass fiber, and the length of the glass fiber is 3 - 6 mm. The glass fiber is immersed in the fermentation broth for treatment. Aureobasidium pullulans is added to the fermentation broth. After fermentation, it is dried, and a pullulan polysaccharide functional coating is loaded on the surface of the glass fiber. The conditions for fermentation in the fermentation broth are: the temperature is 25 - 28 °C, the stirring speed is 100 - 300 rpm, the initial pH is 5.5 - 6.5, and 10 - 20 g of glass fiber is immersed in each liter of the fermentation broth.

[0039] Furthermore, the culture medium components in the fermentation broth are conventional components (carbon source, nitrogen source, inorganic salts, phosphate buffer solution), which will not be elaborated. 0.1% non-ionic surfactant can be added to the fermentation broth. The non-ionic surfactant is Tween-80 to avoid agglomeration of glass fibers. Chloramphenicol (50 μg / mL) for bacteria or Na2SO3 (0.1%) for inhibiting fungal contaminants can also be added to the fermentation broth to avoid contamination by miscellaneous bacteria.

[0040] Furthermore, the preparation method of the modified phosphogypsum powder is: the phosphogypsum is calcined and converted into hemihydrate gypsum. The temperature of the calcination treatment is 120 °C - 180 °C, and the calcination time is 1 - 2 hours. The hemihydrate gypsum and biochar are fully mixed evenly to obtain the modified phosphogypsum powder. The doping amount of biochar is 5% - 20% of the hemihydrate gypsum.

[0041] Furthermore, the additives include a foaming agent, a flame retardant, and a setting regulator.

[0042] Example 2

[0043] A modified phosphogypsum plasterboard without paper face comprises raw materials in the following parts by weight: 80 - 90 parts of modified phosphogypsum powder, 5 - 10 parts of glass fiber, 10 - 20 parts of water, and 1 - 5 parts of additives;

[0044] Wherein the glass fiber is modified glass fiber, and the length of the glass fiber is 3 - 6 mm. The glass fiber is pre-treated by etching to obtain etched glass fiber, so that the surface of the glass fiber has micron-level pits. The pre-treatment by etching is acid etching, alkali etching or laser etching. Acid etching is to soak in 10% HCl or H2SO4 for 30 - 60 minutes, alkali etching is to soak in 5% NaOH for 1 - 2 hours, and micron-level pits are formed on the fiber surface after laser etching, and the specific surface area increases by 50% - 100%, which is beneficial to the attachment of bacteria and polysaccharides.

[0045] Then, the etched glass fiber is immersed in the fermentation broth for post-treatment. Aureobasidium pullulans is added to the fermentation broth. After fermentation, it is dried, and a pullulan functional coating is loaded on the surface of the glass fiber. The conditions for fermentation in the fermentation broth are as follows: the temperature is 25-28 °C, the stirring speed is 100-300 rpm, the initial pH is 5.5-6.5, and 10-20 g of glass fiber is immersed in each liter of the fermentation broth.

[0046] The culture medium components in the fermentation broth are conventional components (carbon source, nitrogen source, inorganic salts, phosphate buffer solution), which will not be elaborated here. 0.1% non-ionic surfactant can be added to the fermentation broth. The non-ionic surfactant is Tween-80 to avoid agglomeration of glass fibers. Chloramphenicol (50 μg / mL) for bacteria or Na2SO3 (0.1%) for inhibiting fungal contaminants can also be added to the fermentation broth to avoid contamination by miscellaneous bacteria.

[0047] Furthermore, the preparation method of the modified phosphogypsum powder is as follows: The phosphogypsum is calcined and converted into hemihydrate gypsum. The temperature of the calcination treatment is 120 °C - 180 °C, and the calcination time is 1 - 2 hours. The hemihydrate gypsum and biochar are fully mixed evenly to obtain the modified phosphogypsum powder. The doping amount of biochar is 5% - 20% of the hemihydrate gypsum.

[0048] Furthermore, the additives include a foaming agent, a flame retardant, and a setting regulator.

[0049] Comparative Example 1

[0050] A modified phosphogypsum plasterboard without paper facings comprises the following raw materials in parts by weight: 80 - 90 parts of gypsum powder, 5 - 10 parts of glass fiber, 10 - 20 parts of water, and 1 - 5 parts of additives;

[0051] Among them, the glass fiber is modified glass fiber, and the length of the glass fiber is 3 - 6 mm. The glass fiber is immersed in the fermentation broth for post-treatment. Aureobasidium pullulans is added to the fermentation broth. After fermentation, it is dried, and a pullulan functional coating is loaded on the surface of the glass fiber. The conditions for fermentation in the fermentation broth are as follows: the temperature is 25-28 °C, the stirring speed is 100-300 rpm, the initial pH is 5.5-6.5, and 10-20 g of glass fiber is immersed in each liter of the fermentation broth.

[0052] The culture medium components in the fermentation broth are conventional components (carbon source, nitrogen source, inorganic salts, phosphate buffer solution), which will not be elaborated here. 0.1% non-ionic surfactant can be added to the fermentation broth. The non-ionic surfactant is Tween-80 to avoid agglomeration of glass fibers. Chloramphenicol (50 μg / mL) for bacteria or Na2SO3 (0.1%) for inhibiting fungal contaminants can also be added to the fermentation broth to avoid contamination by miscellaneous bacteria.

[0053] Before immersing the glass fiber into the fermentation broth, the glass fiber is first subjected to etching pretreatment to obtain etched glass fiber, so that the surface of the glass fiber has micron-sized pits, and then the etched glass fiber is immersed into the fermentation broth for post-treatment. The etching pretreatment is acid etching, alkali etching or laser etching. Acid etching is carried out by soaking in 10% HCl or H2SO4 for 30 to 60 minutes, alkali etching is carried out by soaking in 5% NaOH for 1 to 2 hours, and micron-sized pits are formed on the fiber surface after laser etching, and the specific surface area increases by 50% to 100%, which is beneficial to the attachment of bacteria and polysaccharides.

[0054] Further, the additive includes a foaming agent, a flame retardant, and a setting regulator.

[0055] Comparative Example 2

[0056] A modified phosphogypsum plasterboard without paper surface comprises the following raw materials in parts by weight: 80 to 90 parts of modified phosphogypsum powder, 5 to 10 parts of glass fiber, 10 to 20 parts of water, and 1 to 5 parts of additive;

[0057] The preparation method of the modified phosphogypsum powder is as follows: the phosphogypsum is calcined and converted into hemihydrate gypsum, the calcination temperature is 120°C to 180°C, and the calcination time is 1 to 2 hours. The hemihydrate gypsum and biochar are fully mixed evenly to obtain the modified phosphogypsum powder. The doping amount of biochar is 5% to 20% of the hemihydrate gypsum.

[0058] Further, the additive includes a foaming agent, a flame retardant, and a setting regulator.

[0059] The performance tests were carried out on the plasterboards prepared from the raw materials of the above Examples 1 to 2 and Comparative Examples 1 to 2, and the performance test results are shown in the following table: (Lack of comparison with the prior art)

[0060]

[0061] It can be seen from the table that the glass fiber after etching pretreatment and modified with pullulan polysaccharide functional coating is combined with the modified phosphogypsum powder and applied to the production of plasterboard, and the performance in terms of flexural strength, water absorption rate, mildew resistance, etc. has been greatly improved.

[0062] It should be noted that although the present invention has been described by the above embodiments, the present invention can also have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and deformations to the present invention, but these changes and deformations should all fall within the scope protected by the appended claims of the present invention and their equivalents.

Claims

1. A modified phosphogypsum plasterboard without paper facings, characterized in that: It comprises raw materials in the following parts by weight: 80 - 90 parts of modified phosphogypsum powder, 5 - 10 parts of glass fiber, 10 - 20 parts of water, and 1 - 5 parts of additive; The glass fiber is modified glass fiber. The glass fiber is immersed in the fermentation broth and then treated so that the surface of the glass fiber is loaded with a functional coating.

2. A modified phosphogypsum plasterboard without paper face according to claim 1, characterized in that: Before the glass fiber is immersed in the fermentation broth, it is first subjected to etching pretreatment to obtain etched glass fiber, so that the surface of the glass fiber has micron-sized pits, and then the etched glass fiber is immersed in the fermentation broth for post-treatment.

3. A modified phosphogypsum plasterboard without paper face according to claim 2, characterized in that: The etching pretreatment is acid etching, alkali etching or laser etching.

4. A modified phosphogypsum plasterboard without paper facing according to claim 1 or 2, characterized in that: Aureobasidium pullulans is added to the fermentation broth. After fermentation, it is dried, and a pullulan polysaccharide functional coating is loaded on the surface of the glass fiber.

5. A modified phosphogypsum plasterboard without paper facing according to claim 4, characterized in that: The fermentation conditions in the fermentation broth are: the temperature is 25 - 28 °C, the stirring speed is 100 - 300 rpm, the initial pH is 5.5 - 6.5, and 10 - 20 g of glass fiber is immersed in each liter of fermentation broth.

6. A modified phosphogypsum plasterboard without paper face according to claim 1, characterized in that: The length of the glass fiber is 3 - 6 mm.

7. A modified phosphogypsum plasterboard without paper facing according to claim 1, characterized in that: The preparation method of the modified phosphogypsum powder is: the phosphogypsum is calcined and converted into hemihydrate gypsum, and the hemihydrate gypsum is fully mixed with biochar to obtain the modified phosphogypsum powder.

8. A modified phosphogypsum plasterboard without paper face according to claim 7, characterized in that: The temperature of the calcination treatment is 120 °C - 180 °C, and the calcination time is 1 - 2 hours.

9. A modified phosphogypsum plasterboard without paper facing according to claim 1, characterized in that: The additive includes a foaming agent, a flame retardant, and a setting regulator.

10. The preparation method of a modified phosphogypsum plasterboard without paper surface according to any one of claims 1 to 9, characterized in that: It includes the following steps: Step 1: Mix the prepared modified phosphogypsum powder with water and additive evenly to form a gypsum slurry; Step 2: Add the prepared modified glass fiber to the gypsum slurry in batches, and stir evenly at a low speed to obtain a mixed slurry; Step 3: Pour the mixed slurry into a mold, scrape it flat, let it solidify, and then dry and demold to obtain a gypsum board.

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