CN112194446B - Gypsum casting forming method, gypsum formed product and application - Google Patents

Gypsum casting forming method, gypsum formed product and application Download PDF

Info

Publication number
CN112194446B
CN112194446B CN202011034758.9A CN202011034758A CN112194446B CN 112194446 B CN112194446 B CN 112194446B CN 202011034758 A CN202011034758 A CN 202011034758A CN 112194446 B CN112194446 B CN 112194446B
Authority
CN
China
Prior art keywords
gypsum
parts
raw material
calcium carbonate
calcium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202011034758.9A
Other languages
Chinese (zh)
Other versions
CN112194446A (en
Inventor
何晶
张建龙
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jingmen Qian Nian Jian Health Care Technology Co ltd
Original Assignee
Jingmen Qian Nian Jian Health Care Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jingmen Qian Nian Jian Health Care Technology Co ltd filed Critical Jingmen Qian Nian Jian Health Care Technology Co ltd
Priority to CN202011034758.9A priority Critical patent/CN112194446B/en
Publication of CN112194446A publication Critical patent/CN112194446A/en
Application granted granted Critical
Publication of CN112194446B publication Critical patent/CN112194446B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/142—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements containing synthetic or waste calcium sulfate cements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor
    • B28B3/02—Producing shaped articles from the material by using presses; Presses specially adapted therefor wherein a ram exerts pressure on the material in a moulding space; Ram heads of special form
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B11/00—Calcium sulfate cements
    • C04B11/02—Methods and apparatus for dehydrating gypsum
    • C04B11/024—Ingredients added before, or during, the calcining process, e.g. calcination modifiers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B11/00—Calcium sulfate cements
    • C04B11/02—Methods and apparatus for dehydrating gypsum
    • C04B11/028—Devices therefor characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
    • C04B28/146—Calcium sulfate hemi-hydrate with a specific crystal form alpha-hemihydrate
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
    • C04B28/147—Calcium sulfate hemi-hydrate with a specific crystal form beta-hemihydrate
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00008—Obtaining or using nanotechnology related materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength

Abstract

The invention relates to a gypsum casting forming method which comprises the steps of uniformly mixing a gypsum raw material and a binder, carrying out die-casting forming, treating in deionized water for 0.5-4 s, standing for 30-60 minutes, and passivating in deionized water again to obtain a product. The invention also discloses a molded product obtained by the method and application. The product prepared by the method has high bending strength and compressive strength, large surface hardness, good disintegration resistance, high product precision, simple and convenient forming process, easy industry and wide application in the fields of medical care, electronic industry, building decoration, industrial art and the like.

Description

Gypsum casting forming method, gypsum formed product and application
Technical Field
The invention relates to the technical field of gypsum, in particular to a gypsum casting forming method, a gypsum formed product and application.
Background
Gypsum is an important material in the field of medical health care product application. The medical gypsum has higher requirements on the performances of the gypsum such as hardness, density, strength and the like, but the performances of the existing gypsum are difficult to meet the requirements.
The invention patent 'a high-strength gypsum for dentistry' with application number 201210000045.X discloses a gypsum for dentistry, which comprises 100 parts of alpha-hemihydrate gypsum powder; 3-10 parts of a reinforcing agent; 2-7 parts of a water reducing agent; 0-5 parts of cement are uniformly mixed to prepare the cement. The invention adopts the mode of adding the additive into the common alpha-semi-hydrated gypsum to improve the setting performance of the gypsum and improve the density, the strength and the hardness of the gypsum. But the gypsum still has the defects that the performance is insufficient, and the density, the strength and the hardness of the finished gypsum product cannot meet the requirements.
It can be seen that the existing gypsum has the defects of insufficient strength and easy disintegration, and is difficult to meet the requirements.
Disclosure of Invention
In view of the above, there is a need to provide a gypsum casting method to solve the problems of insufficient strength and easy disintegration of the existing gypsum.
The invention provides a gypsum casting forming method, which comprises the steps of uniformly mixing a gypsum raw material, a binder and a crystal modifier, and performing die-casting forming; and soaking the formed product into deionized water for 0.5-4 s, standing for 30-60 min, and storing in the deionized water for not less than 10 h.
Preferably, the gypsum raw material comprises the following components in parts by weight: 500-1000 parts of nano calcium carbonate, 100-200 parts of calcium sulfate II type variant and 0-50 parts of salt gypsum powder.
Specifically, the microstructure of the nano calcium carbonate is a hydrophobic surface formed on the surface of a calcium carbonate skeleton and deposited with calcium acetate and calcium stearate, and the hydrophobic surface accounts for 60-75% of the surface area of the calcium carbonate skeleton.
Specifically, the calcium sulfate II variant is prepared by dehydrating and calcining phosphogypsum serving as a raw material, and an activating agent is added in the calcining process, wherein the activating agent comprises hydrated aluminum magnesium potassium sulfate, sodium silicate and hydrated aluminum magnesium silicate, and the mass ratio of the hydrated aluminum magnesium potassium sulfate, the sodium silicate and the hydrated aluminum magnesium silicate is (5-10): (2-4): 1-2.
Specifically, the gypsum raw material further comprises the following components in parts by weight: 10-50 parts of diatomite, 5-20 parts of high bauxite and 1-5 parts of glass fiber.
Further, the binder is renewable latex powder and pregelatinized starch, and the dosage of the binder is 1-4% of the weight of the gypsum raw material.
Preferably, the time for soaking the formed product into deionized water is 1-2 s.
The invention also provides a gypsum molding product obtained by the gypsum casting molding method.
The invention also provides application of the gypsum molding product in preparation of medical health products, electronic products, building decoration products and industrial art products.
Has the advantages that:
according to the invention, a high-strength molded product can be obtained through dry mixing and rapid hydration treatment; the nanometer calcium carbonate and calcium sulfate II type variant deposited with the calcium acetate and stearic acid modified hydrophobic surface are used as gypsum raw materials, so that the product strength can be further improved, and excellent anti-disintegration performance can be obtained, the whole gypsum casting forming process is simple and convenient, industrialization is easy to realize, the obtained formed product has high strength and high anti-disintegration performance, and the gypsum casting forming process can be applied to the fields of medical health care products and the like, such as the fields of manufacturing health care pillows, cushions, mattresses and aromatherapy products.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The embodiment of the invention provides a gypsum casting forming method, which comprises the steps of uniformly mixing a gypsum raw material, a binder and a crystal modifier, and performing die-casting forming; and soaking the formed product into deionized water for 0.5-4 s, standing for 30-60 min, and storing in the deionized water for not less than 10 h.
The preparation method of the super-strong-hardness gypsum casting provided by the invention adopts a new formula and dosage, changes the defects of small strength and hardness of gypsum in the traditional wet casting process by adopting dry mixing and special water treatment and water hardening treatment, is simple and convenient, and is easy to popularize in practical application.
Gypsum raw material
Specifically, the gypsum raw material can be selected from conventional alpha-hemihydrate gypsum powder, beta-hemihydrate gypsum powder, and at least one of nano calcium carbonate, nano calcium sulfate II type variant and salt gypsum powder.
Preferably, the gypsum raw material comprises the following components in parts by weight: 500-1000 parts of nano calcium carbonate, 100-200 parts of calcium sulfate II type variant and 0-50 parts of salt gypsum powder.
The preparation process of the nano calcium carbonate comprises the following steps:
and (2) at the temperature of 25-30 ℃, putting a bottom material reactant of sodium carbonate into a four-tube reactor, adding a surfactant, pre-stirring at 1500-2000 rpm, then adding a calcium chloride emulsion at a titration speed of 3ml/min, simultaneously dropwise adding an acetate solution and a sodium stearate solution at 3ml/min, and stopping reaction until the pH value in the reactor is 6.8-7.2 under the condition of stirring at 1000-1500 rpm. The reaction solution is obtained by emulsifying, filtering and drying.
Wherein the dosage ratio of the sodium carbonate to the calcium chloride is 1 (3-5), and optionally 1: 4; the dosage of the surfactant is 1.3-1.5% of the mass of the sodium carbonate, and 1.4% of the surfactant can be selected; the dosage of the acetic ester and the dosage of the sodium stearate are 0.08-0.1 per mill of the mass of the sodium carbonate, and 0.09 per mill can be selected.
The particle size of the obtained calcium carbonate is 10-25 nm, the microstructure of the nano calcium carbonate is a hydrophobic surface formed by a calcium carbonate skeleton and deposited with calcium acetate and calcium stearate on the surface, and the area proportion of the hydrophobic surface to the surface of the calcium carbonate skeleton is 60-75%.
Specifically, as shown in table 1, the ratio of the amount of sodium carbonate to the amount of calcium chloride (labeled a), the amount of surfactant (labeled B), the amount of acetate, and the amount of sodium stearate (labeled C) in the preparation process can have an effect on the ratio of the area of the hydrophobic surface to the surface of the calcium carbonate skeleton.
TABLE 1
Examples A B C Range of particle size Hydrophobic surface area ratio
Example 1 1:4 1.3％ 0.08‰,0.08‰ 10～25nm 72.8％
Example 2 1:4 1.4％ 0.08‰,0.08‰ 10～20nm 71.9％
Example 3 1:4 1.5％ 0.08‰,0.08‰ 10～15nm 68.7％
Example 4 1:4 1.5％ 0.09‰,0.09‰ 10～15nm 70.3％
Example 5 1:4 1.5％ 0.1‰,0.1‰ 10～15nm 72.1％
Comparative example 1 1:2 1.5％ 0.1‰,0.1‰ 8～15nm 44.7％
Comparative example 2 1:6 1.5％ 0.1‰,0.1‰ 30～45nm 65.3％
Comparative example 3 1:4 1.2％ 0.1‰,0.1‰ 20～35nm 56.3％
Comparative example 4 1:4 1.6％ 0.1‰,0.1‰ 8～15nm 43.3％
Comparative example 5 1:4 1.5％ 0.11‰,0.11‰ 10～15nm 80.2％
Comparative example 6 1:4 1.5％ 0.07‰,0.07‰ 10～15nm 54.7％
Comparative example 7 1:6 1.6％ 0.11‰,0.11‰ 8～10nm 71.5％
As can be seen from table 1, in the process of preparing nano calcium carbonate, the amounts of sodium carbonate and calcium chloride, surfactant, acetate, and sodium stearate are limited, so that a hydrophobic surface with a suitable area ratio can be formed on the surface of the calcium carbonate skeleton, thereby facilitating the subsequent hydration process treatment and achieving a better effect.
The preparation process of the calcium sulfate II variant comprises the following steps:
the principle of preparing anhydrite by taking phosphogypsum as a raw material is as follows: generally, the dihydrate gypsum begins to dehydrate at 130 ℃ (atmospheric pressure), and when the temperature reaches above 160 ℃, the hemihydrate gypsum is gradually converted into anhydrous gypsum. The anhydrous gypsum is classified into type III anhydrous gypsum, type II anhydrous gypsum and type I anhydrous gypsum according to the corresponding dehydration temperature. The type III anhydrous gypsum is also called soluble anhydrous gypsum. Generally, the semi-hydrated gypsum is formed by dehydrating semi-hydrated gypsum at 160-220 ℃. When the dehydration temperature is 360-1180 ℃, the III type soluble anhydrous gypsum can be converted into II type anhydrous gypsum. Type ii anhydrite can be divided into 3 variants: slowly soluble anhydrous gypsum is obtained at the temperature of 360-500 ℃; insoluble anhydrous gypsum is obtained at 500-700 ℃; the cast floor gypsum (or called floor gypsum) is obtained at 700-1180 ℃. The type I anhydrous gypsum is CaSO type II generated at 1180 DEG C4To form I CaSO4Is obtained by the transformation of (a). Calcium sulfate in phosphogypsum is substantially CaSO4·2H2The form of O exists.First, it must be converted to CaSO at high temperature4Form II variant, rendering it insoluble or slightly soluble anhydrite.
The conventional calcium sulfate II variant has high strength, but has extremely low reaction speed with water, is not beneficial to the subsequent water treatment of the invention, and needs to be excited by adding a certain amount of activating agent in the high-temperature calcination process, SO the invention improves the activating agent in the formation process of the calcium sulfate II variant, and the activating agent comprises hydrated aluminum magnesium potassium sulfate (KAl (SO)4)2·12H2O-MgSO4·7H2O), hydrated magnesium aluminum silicate (3 MgO.1.5 Al)2O3·8SiO2·9H2O) and sodium silicate (NaSiO)3). After calcination, a powder having an average particle size of not more than 0.01mm is produced by conventional grinding.
Specifically, in the calcining process of the calcium sulfate II type variant provided by the invention, the mass ratio of the components of the activator is hydrated aluminum magnesium sulfate potassium: sodium silicate: the hydrated aluminum-magnesium silicate (5-10): (2-4): 1-2), and the addition amount of the activating agent is 1-3% of the mass of the calcium sulfate II type variant. Thus, the reaction speed with water can be increased, and the subsequent water treatment is facilitated. The component ratios of the activators are shown in Table 2.
TABLE 2
Examples Component proportion of activator
Example 6 5:2:1
Example 7 8:2:1
Example 8 10:2:1
Example 9 10:3:1
Example 10 10:4:1
Example 11 10:4:2
Comparative example 8 4:2:1
Comparative example 9 11:2:1
Comparative example 10 10:1:1
Comparative example 11 10:5:1
Comparative example 12 10:4:0
Comparative example 13 10:4:3
The salt gypsum is a compound formed by chemical crystallization and precipitation in the conventional brine refining process, and mainly comprises calcium sulfate dihydrate, calcium sulfate, magnesium carbonate and clay impurities, and the attached water content of the salt gypsum is not less than 15%.
Further, the gypsum raw material also comprises 10-50 parts of diatomite, 5-20 parts of high-alumina bauxite and 1-5 parts of glass fiber.
The total formulation for the gypsum raw material is shown in table 3. In table 3, the nano calcium carbonate is labeled as Y1, the calcium sulfate type II modification is labeled as Y2, the salt gypsum powder is labeled as Y3, the α gypsum powder is labeled as α, the diatomaceous earth is labeled as Y4, the high alumina is labeled as Y5, and the glass fiber is labeled as Y6. Note that in table 3, the term "parts" merely refers to the weight ratio of each component in the gypsum raw material, and does not represent the actual weight thereof, and finally, each set of examples and comparative examples are prepared to actual consistent weight by the above-mentioned ratio for comparison. Y1 sample selection means that in the total formula of gypsum raw materials, the preparation samples selected by the nano calcium carbonate are selected according to the examples and the comparative examples listed in the table 1; y2 selection means that in the total formulation of gypsum raw material, the preparation samples selected for the calcium sulfate type II variant were selected according to the examples and comparative examples listed in Table 2; the salt gypsum is obtained by a conventional synthesis method, mainly comprises calcium sulfate dihydrate, calcium sulfate, magnesium carbonate and clay impurities, and has an attached water content of not less than 15%.
Wherein, the gypsum raw material of the embodiment 12 is directly selected from the commonly used alpha-hemihydrate gypsum powder. The gypsum raw material of the comparative example 29 also adopts alpha-hemihydrate gypsum powder (the dosage is the same as that of the example 12), 1% of pretreating agent is added, the crystal transformation agent (aluminum sulfate) is added and dissolved in deionized water, then the mixture is poured into the alpha-hemihydrate gypsum sample and evenly stirred, then the mixture is manually made into spheres with the size of about 5cm, the spheres are placed into an autoclave, the phosphogypsum doped with the crystal transformation agent is subjected to hydrothermal treatment under the conditions of 0.17MPa of autoclave pressure, 120 ℃ of autoclave temperature and 4 hours of autoclave temperature to prepare alpha-hemihydrate gypsum, finally, the sample is continuously dried under the normal pressure with the autoclave temperature kept unchanged, and the prepared alpha-hemihydrate gypsum sample is taken out after the test is finished. In Table 3, the total weight of gypsum materials in examples 12 to 27 and comparative examples 14 to 29 were equal.
TABLE 3
Figure BDA0002704859360000071
Figure BDA0002704859360000081
Gypsum casting forming method
The gypsum casting forming method provided by the invention also uses a binder, wherein the binder is renewable latex powder and pregelatinized starch, the use amount of the binder is 1-4% of the weight of the gypsum raw material, and the binder can play a role in binding in the processes of uniformly mixing and forming the gypsum raw material and prepare for hydration treatment of the gypsum raw material. The crystal transformation agent is aluminum sulfate, and the dosage of the crystal transformation agent is 1-4 per mill of the weight of the gypsum raw material.
Secondly, the molded product is immersed in deionized water for 0.5-4 s, preferably 1-2 s, so that the surface of the molded product is quickly hardened to improve the strength and prevent the molded product from disintegrating in the later aging process.
The gypsum raw materials corresponding to the examples in table 3 were cast and molded, and the various factors affecting the molding process during the molding process were counted and listed in table 4. The gypsum raw materials used in comparative examples 30 to 34 are the same as those used in example 20.
TABLE 4
Figure BDA0002704859360000082
Figure BDA0002704859360000091
Evaluation of Molding product Properties
1. Compressive strength
The 2h flexural strength and the drying compressive strength are tested according to the method of JC/T2038-2010 alpha-type high-strength gypsum. The gypsum shaped products prepared according to the invention were taken, tested, averaged and recorded in table 4.
2. Resistance to disintegration
The molded products prepared in the above examples and comparative examples were taken out of deionized water, dried by suction, stored at 20 ℃ and a humidity of about 40% for 28 days, and prepared into disintegration test specimens.
And secondly, recording the initial weight of the sample, and performing a disintegration resistance experiment on the sample under the pressure intensity which is 1.2 times of the maximum 2h bending strength of the sample on a compression resistance experiment machine.
Thirdly, in the test process, a group of readings of the weighing device is recorded every 3min in the first 30min, the reading is recorded every 30min in the first 30min, the data is recorded every 1h after 5h, and the test is performed by adding one medicine for the disintegration rate of less than 0.1% min1To end criteria.
(iv) the disintegration rate is a dimensionless parameter and can be calculated by the following formula, At is 100% × (R)0－Rf)/R0And recording the minimum time for which the disintegration amount tends to be stable, namely the disintegration time (h). Wherein At represents the disintegration amount (%) of the sample At time t, R0The initial weight of the sample at the start of the test is shown, and Rt represents the weight of the sample at time t.
As can be seen from Table 4:
1. example 12 the gypsum sample obtained by dry mixing and rapid hydration according to the present invention has a 2h flexural strength and a baking compressive strength higher than those of comparative example 29, and the gypsum sample obtained by dry mixing has a disintegration resistance better than that of comparative example 29. This demonstrates that the dry mixing and rapid hydration process provided by the present invention can yield gypsum samples of high strength and excellent disintegration resistance.
2. Further, the gypsum samples of examples 13-17 were prepared using nano calcium carbonate and calcium sulfate type II variants, and both the strength and the anti-disintegration performance of the gypsum samples were improved, because the nano calcium carbonate had a hydrophobic surface with calcium acetate and calcium stearate deposited on the surface, and the surface of the gypsum product after molding provided a certain hydrophobic capacity, reducing the time for water absorption and setting. After the calcium sulfate II type variant is activated, the solidification time is further reduced, a solidification layer can be formed on the surface of a formed finished product after the calcium sulfate II type variant is treated for 0.5-4 s in the hydration treatment process, and then the inner part of the calcium sulfate II type variant can be further solidified by continuously aging in water, so that the strength of the calcium sulfate II type variant is improved, and therefore, compared with the embodiment 12, the calcium sulfate II type variant can obtain a product with higher strength and an anti-disintegration effect. Further, as in comparative examples 30-34, the flexural strength and the oven dry compressive strength of 2h are significantly reduced compared to example 20, especially the comparative example 30 has not undergone hydration treatment for 0.5-4 s, the disintegration amount is significantly increased, and the disintegration time is significantly reduced; the fact shows that the adoption of the II type variant of the nano calcium carbonate and the calcium sulfate can improve the strength and the anti-disintegration effect of the product through rapid hydration treatment for 0.5 to 4 seconds.
3. In the embodiment 20, compared with the comparative examples 19 to 22 respectively, the selection of the nano calcium carbonate and the calcium sulfate II type variant is limited, the area ratio of the hydrophobic surface of the nano calcium carbonate is 60 to 75 percent, the activating agent adopted in the activation process of the calcium sulfate II type variant is a mixture of hydrated aluminum magnesium potassium sulfate, sodium silicate and hydrated aluminum magnesium silicate, the ratio is limited to (5 to 10): 2 to 4): 1 to 2, and the using amount is limited to 1 to 3 percent of the mass of the calcium sulfate II type variant, and the result shows that the product strength and the anti-disintegration effect of the embodiment 20 are better than those of the comparative examples 19 to 22.
4. The invention further optimizes the selected gypsum raw material, adds the salt gypsum, and further adds the diatomite, the high alumina bauxite and the glass fiber, thereby further improving the strength and the anti-disintegration effect of the product. (e.g., examples 18-27, comparative examples 14-18, and comparative examples 23-28).
In conclusion, the invention can obtain a high-strength formed product through dry mixing and rapid hydration treatment, and the product strength can be further improved and excellent disintegration resistance can be obtained by adopting the nano calcium carbonate and calcium sulfate type II variant deposited with the calcium acetate and stearic acid modified hydrophobic surface as the gypsum raw material, so that the whole gypsum casting forming process is simple and convenient and easy to industrialize, and the obtained formed product has high strength and high disintegration resistance, can be applied to the fields of medical health care products and the like, such as the fields of manufacturing health care pillows, cushions, mattresses and aromatherapy products.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims (7)

1. A gypsum casting forming method is characterized by comprising the steps of uniformly mixing a gypsum raw material, a binder and a crystal modifier, and performing die-casting forming; soaking the molded product into deionized water for 0.5-4 s, taking out, standing for 30-60 min, and storing in the deionized water for no less than 10 h;
the gypsum raw material comprises the following components in parts by weight: 500-1000 parts of nano calcium carbonate, 100-200 parts of calcium sulfate II type variant and 0-50 parts of salt gypsum powder;
the calcium sulfate II variant is prepared by dehydrating and calcining phosphogypsum serving as a raw material, and an activating agent is added in the calcining process, wherein the activating agent comprises hydrated aluminum-magnesium potassium sulfate, sodium silicate and hydrated aluminum-magnesium silicate, and the mass ratio of the hydrated aluminum-magnesium potassium sulfate, the sodium silicate and the hydrated aluminum-magnesium silicate is (5-10) to (2-4) to (1-2);
the microstructure of the nano calcium carbonate is a hydrophobic surface formed by calcium acetate and calcium stearate deposition on the surface of a calcium carbonate skeleton.
2. The gypsum foundry molding method of claim 1, wherein the hydrophobic surface accounts for 60 to 75% of the surface area of the calcium carbonate skeleton.
3. The gypsum casting method of claim 2, wherein the gypsum raw material further comprises the following components in parts by weight: 10-50 parts of diatomite, 5-20 parts of high bauxite and 1-5 parts of glass fiber.
4. The gypsum casting method of any one of claims 1-2, wherein the binder is a renewable latex powder and pregelatinized starch, and the amount of the binder is 1-4% of the weight of the gypsum raw material.
5. The gypsum foundry shape method of any one of claims 1-2, wherein the time for which the shaped product is immersed in deionized water is 1-2 seconds.
6. A gypsum shaped product obtained by the gypsum foundry shaping method of any one of claims 1 to 5.
7. Use of the gypsum-molded product of claim 6 for the production of medical care products, electronic products, building decoration products and industrial art products.
CN202011034758.9A 2020-09-27 2020-09-27 Gypsum casting forming method, gypsum formed product and application Active CN112194446B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011034758.9A CN112194446B (en) 2020-09-27 2020-09-27 Gypsum casting forming method, gypsum formed product and application

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011034758.9A CN112194446B (en) 2020-09-27 2020-09-27 Gypsum casting forming method, gypsum formed product and application

Publications (2)

Publication Number Publication Date
CN112194446A CN112194446A (en) 2021-01-08
CN112194446B true CN112194446B (en) 2022-06-21

Family

ID=74006987

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011034758.9A Active CN112194446B (en) 2020-09-27 2020-09-27 Gypsum casting forming method, gypsum formed product and application

Country Status (1)

Country Link
CN (1) CN112194446B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113480210A (en) * 2021-08-20 2021-10-08 河南永泰石膏有限公司 Process for producing alpha high-strength gypsum powder by using industrial byproduct gypsum
CN113480283A (en) * 2021-08-24 2021-10-08 艾思尔信息科技(上海)有限公司 Preparation method of three-dimensional super-hydrophobic gypsum with ultrahigh water-cement ratio
WO2024070323A1 (en) * 2022-09-26 2024-04-04 吉野石膏株式会社 Dental gypsum composition

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0198780A1 (en) * 1985-03-15 1986-10-22 A. Weber, S.A. Process for the fast hardening of natural anhydrite
CN105906293A (en) * 2016-04-15 2016-08-31 湖北森绿环保材料有限公司 Flue gas desulfurization gypsum high-strength crystal decorative sheet and manufacturing method thereof
CN106699091A (en) * 2016-11-21 2017-05-24 同济大学 High-viscosity water-retaining plastering mortar taking phosphogypsum hydraulic composite cementing material as main material and preparation method thereof
CN107337416A (en) * 2017-07-12 2017-11-10 合肥梵腾环保科技有限公司 A kind of preparation method of environmentally friendly plasterboard
CN110128045A (en) * 2019-04-30 2019-08-16 江苏一夫科技股份有限公司 II type anhydrous gypsum fast hydration exciting agent of one kind and fast hydration method
CN110218069A (en) * 2019-07-01 2019-09-10 成都建工赛利混凝土有限公司 A kind of water-fast 3D printing gypsum mortar and preparation method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0198780A1 (en) * 1985-03-15 1986-10-22 A. Weber, S.A. Process for the fast hardening of natural anhydrite
CN105906293A (en) * 2016-04-15 2016-08-31 湖北森绿环保材料有限公司 Flue gas desulfurization gypsum high-strength crystal decorative sheet and manufacturing method thereof
CN106699091A (en) * 2016-11-21 2017-05-24 同济大学 High-viscosity water-retaining plastering mortar taking phosphogypsum hydraulic composite cementing material as main material and preparation method thereof
CN107337416A (en) * 2017-07-12 2017-11-10 合肥梵腾环保科技有限公司 A kind of preparation method of environmentally friendly plasterboard
CN110128045A (en) * 2019-04-30 2019-08-16 江苏一夫科技股份有限公司 II type anhydrous gypsum fast hydration exciting agent of one kind and fast hydration method
CN110218069A (en) * 2019-07-01 2019-09-10 成都建工赛利混凝土有限公司 A kind of water-fast 3D printing gypsum mortar and preparation method thereof

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Preparation of hardened tiles from waste phosphogypsum by a new intermittent pressing hydration;Jun Zhoua等;《CERAMICS INTERNATIONAL》;20160501;第42卷(第6期);第7237-7245页 *
硬脂酸钙改性纳米碳酸钙的效果研究;刘立华;《化工科技市场》;20101012(第10期);第31-33页 *

Also Published As

Publication number Publication date
CN112194446A (en) 2021-01-08

Similar Documents

Publication Publication Date Title
CN112194446B (en) Gypsum casting forming method, gypsum formed product and application
JP3607291B2 (en) Coagulation and curing accelerators for silica based hydraulic binders
JPS61111983A (en) Manufacture of foamed concrete
CN110436874A (en) A kind of high-performance ardealite based self-leveling mortar preparation method
US6398864B1 (en) Pottery plaster formulations for the manufacture of plaster molds
CN113683078A (en) Preparation method of nano carbon dots for modified cement-based material, nano carbon dots and concrete
CN113428887B (en) Method for preparing alpha high-strength gypsum from industrial byproduct gypsum
Lv et al. The performance and mechanism analysis of cement pastes added to aluminum sulfate-based low-alkali setting accelerator
CN114685077B (en) Slow-release type coagulation promoting composite material, preparation method thereof and application thereof in cement-based materials
Zhang et al. Hydration and strength development in magnesium oxysulfate (MOS) cement incorporating silicic acid
CN108101406A (en) A kind of super high-early concrete early strength agent and preparation method thereof
CN110981259B (en) Additive for improving crystallinity of hydro-thermal synthesis hydrated calcium silicate
KR100559477B1 (en) Cement composition and method of making concrete and concrete products using it
CN114685090A (en) Controlled-release early-strength composite material, preparation method and application thereof in cement-based material
CN112430003B (en) Size-controllable nano composite early strength agent and preparation method thereof
CN110963744A (en) Liquid expanding agent capable of expanding step by step and preparation method thereof
CN116143438A (en) Cascade hydration super-early-strength material for steam-cured concrete products
CN109734411B (en) Preparation method of water-resistant magnesium-based cementing material
Liu et al. Synthesis of nanoparticles from slag and their enhancement effect on hydration properties of CaO/CaSO4-activated slag binder
JPS5812235B2 (en) Setsukou Shinjiyouketsuyouseni no Seizouhouhou
Zhang et al. Improvement on corrosion resistance of gypsum for ceramics molding with soluble salts
CN112979204A (en) Magnesium-doped calcium silicate crystal nucleus early strength agent with long-term stability and preparation method thereof
JP2003171161A (en) Heat resisting, high strength concrete, and production method therefor
CN112707691B (en) Self-compacting concrete and preparation method thereof
Zhao et al. Pore structure formation and hydration characteristics of cement paste with temperature rising inhibitor

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant