CN116676672A - Method for preparing calcium sulfate whisker from mirabilite gypsum - Google Patents
Method for preparing calcium sulfate whisker from mirabilite gypsum Download PDFInfo
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- CN116676672A CN116676672A CN202310647791.6A CN202310647791A CN116676672A CN 116676672 A CN116676672 A CN 116676672A CN 202310647791 A CN202310647791 A CN 202310647791A CN 116676672 A CN116676672 A CN 116676672A
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- Prior art keywords
- gypsum
- calcium sulfate
- mirabilite
- slurry
- sulfate whisker
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- 239000010440 gypsum Substances 0.000 title claims abstract description 70
- 229910052602 gypsum Inorganic materials 0.000 title claims abstract description 70
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 title claims abstract description 46
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 title claims abstract description 44
- 239000010446 mirabilite Substances 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims abstract description 23
- 239000002994 raw material Substances 0.000 claims abstract description 22
- 239000002002 slurry Substances 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000003756 stirring Methods 0.000 claims abstract description 17
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 12
- 238000001035 drying Methods 0.000 claims abstract description 11
- 239000000047 product Substances 0.000 claims abstract description 11
- 239000012065 filter cake Substances 0.000 claims abstract description 10
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 8
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 8
- 238000001027 hydrothermal synthesis Methods 0.000 claims abstract description 7
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 6
- 239000011575 calcium Substances 0.000 claims abstract description 6
- 238000000926 separation method Methods 0.000 claims abstract description 6
- 238000005406 washing Methods 0.000 claims abstract description 6
- 150000001879 copper Chemical class 0.000 claims abstract description 4
- 239000013078 crystal Substances 0.000 claims abstract description 4
- 238000001914 filtration Methods 0.000 claims abstract description 4
- 239000007952 growth promoter Substances 0.000 claims abstract description 4
- 159000000003 magnesium salts Chemical class 0.000 claims abstract description 4
- 238000005086 pumping Methods 0.000 claims abstract description 4
- 230000003301 hydrolyzing effect Effects 0.000 claims abstract description 3
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 10
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 6
- 239000007822 coupling agent Substances 0.000 claims description 5
- -1 polytetrafluoroethylene Polymers 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 239000010439 graphite Substances 0.000 claims description 4
- 229910002804 graphite Inorganic materials 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 4
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 4
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 3
- 235000021355 Stearic acid Nutrition 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 3
- 239000008117 stearic acid Substances 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 abstract description 6
- 230000008569 process Effects 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 9
- 239000002699 waste material Substances 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000003912 environmental pollution Methods 0.000 description 3
- 239000012774 insulation material Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- 150000004683 dihydrates Chemical class 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000002783 friction material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000005060 rubber Substances 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 230000009970 fire resistant effect Effects 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 239000012767 functional filler Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- RSIJVJUOQBWMIM-UHFFFAOYSA-L sodium sulfate decahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=O RSIJVJUOQBWMIM-UHFFFAOYSA-L 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000012745 toughening agent Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/46—Sulfur-, selenium- or tellurium-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
- C30B29/62—Whiskers or needles
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
- C30B7/10—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions by application of pressure, e.g. hydrothermal processes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention discloses a method for preparing calcium sulfate whiskers by using mirabilite gypsum, which relates to the technical field of calcium sulfate whisker preparation and comprises the following steps: s1, pretreatment of raw materials: dissolving and stirring the raw material mirabilite gypsum in water at normal temperature, leading out upper slurry, stirring and hydrolyzing, adding calcium water, fully stirring, adding dilute sulfuric acid to adjust the PH, washing for 2-3 times, filtering to obtain a filter cake, and adding water to prepare uniform gypsum slurry; s2, preparing whiskers by a hydrothermal method and modifying: adding 2% -10% of magnesium salt or copper salt crystal form growth promoter into the gypsum slurry obtained in the step S1, adding the gypsum slurry into a spherical kettle type reactor, pumping in a stabilizing and modifying agent by using a pressure pump for 0.5-2 h, and then carrying out solid-liquid separation on the reacted slurry to obtain a filter cake; s3, drying the product. The invention adopts the technological process and optimized technological operation condition, so that the finally obtained calcium sulfate whisker has uniform morphology, proper length-diameter ratio and high yield.
Description
Technical Field
The invention relates to the technical field of calcium sulfate whisker preparation, in particular to a method for preparing calcium sulfate whisker by using mirabilite gypsum.
Background
The gypsum whisker is a novel inorganic material with very high comprehensive performance. The material has the advantages of high strength, good toughness, high modulus, high dielectric strength, wear resistance, high temperature resistance, corrosion resistance, good infrared reflectivity, easy surface treatment, strong affinity with high molecular polymer, good compatibility, smoothness, no toxicity and the like. Can be used as a reinforcing toughening agent or a functional filler in high-insulation materials of ceramics, metals, resins, plastics, rubber, paint, oil paint, papermaking, asphalt, friction and sealing materials and coated wires; but also can be used as heat insulation material, flame retardant material, fire-resistant heat insulation material and infrared reflection material; can also be used as a filter, a catalyst and a carrier. The price of the gypsum whisker is only 1/200-1/300 of that of the silicon carbide whisker, and the gypsum whisker has incomparable cost performance with other whiskers, has wide application range and stronger market competitiveness.
According to the situation of using gypsum whisker abroad, the dosage of the gypsum whisker is 3-30% of the base material, generally 5-15%, if 5% is added, if the gypsum whisker is used in paper making industry, the annual output total amount of domestic paper is more than 500 ten thousand tons, if 10% of paper is added with gypsum whisker, 50 x 6% = 30 ten thousand tons are required; if the method is used in the plastic and rubber industries, the total domestic yield is more than 800 ten thousand tons, if 10% of the product is added with gypsum whisker, the gypsum whisker needs 80 multiplied by 5% =4ten thousand tons, and in addition, the gypsum whisker is applied to the fields of friction materials, environmental engineering, light building materials and the like, and the estimated market prospect can reach 200 ten thousand tons/year. The gypsum whisker has wide application, large market demand, low production cost (raw materials usually adopt byproducts or waste with low industrial cost) and strong market competitiveness. Gypsum whisker products have been included in the national encouragement class high-tech industry catalog products.
The raw materials for preparing the gypsum whisker in China are very rich, the cost is low and the raw materials are easy to obtain, and a lot of raw materials can come from byproducts and wastes in the production process, and only industrial wastes which can be used for preparing the gypsum whisker in the tribute area of China mainly comprise mirabilite gypsum 3 kilotons/year.
The mirabilite gypsum is milky white waste residue produced by extracting sodium sulfate from mirabilite and gypsum paragenetic ore or producing mirabilite from glauber salt. In recent years, the annual output of mirabilite in China is maintained to be about 1000 ten thousand tons, and the production of mirabilite gypsum in 2020 is about 400 ten thousand tons.
Because the components in the mirabilite gypsum are complex, in the method for preparing the calcium sulfate whisker by utilizing the mirabilite gypsum in the prior art, all the components in the mirabilite gypsum cannot be fully utilized, so that the preparation raw materials cannot be fully utilized, and the production benefit is affected.
Therefore, the invention aims to provide a novel method for preparing calcium sulfate whiskers by using mirabilite gypsum, so as to solve the problems.
Disclosure of Invention
The invention aims to solve the problems and provides a method for preparing calcium sulfate whiskers by using mirabilite gypsum.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
the invention provides a method for preparing calcium sulfate whisker from mirabilite gypsum, which comprises the following steps:
s1, pretreatment of raw materials:
dissolving and stirring the raw material mirabilite gypsum in water at normal temperature, leading out upper slurry, stirring and hydrolyzing, adding calcium water, fully stirring, adding dilute sulfuric acid to adjust the PH, washing for 2-3 times, filtering to obtain a filter cake, and adding water to prepare uniform gypsum slurry;
s2, preparing whiskers by a hydrothermal method and modifying:
adding 2% -10% of magnesium salt or copper salt crystal form growth promoter into the gypsum slurry obtained in the step S1, adding the gypsum slurry into a spherical kettle type reactor, heating to 120 ℃, starting timing reaction for 3.5 hours, pumping a stabilizing and modifying agent by using a pressure pump, modifying for 0.5-2 hours, and then carrying out solid-liquid separation on the reacted slurry to obtain a filter cake;
s3, drying a product:
washing the filter cake obtained by solid-liquid separation in the step S2 with cold water, and drying for 20-60 min under the power of 500-1000W by microwaves to obtain a calcium sulfate whisker product.
Further, the calcium water added in the step S1 is 0.6-1.6 mol/L.
Further, dilute sulfuric acid is added in the step S1 to adjust the PH to 2-6.
Further, the stabilizing and modifying agent in the step S2 comprises stearate, stearic acid, a silane coupling agent or a titanate coupling agent, and the stabilizing and modifying agent accounts for 0.5-4% of the mass of the gypsum.
Further, the spherical kettle reactor in the step S1 is a spherical kettle reactor with a stirring jacket and a corrosion-resistant lining material lined with polytetrafluoroethylene filled graphite.
In the scheme of the invention, mirabilite gypsum is taken as a raw material, and in the aspect of raw material pretreatment, water is added at normal temperature for dissolution and stirring, upper slurry is led out for stirring and hydrolysis, so that the available components in the mirabilite gypsum can be hydrolyzed as much as possible, and each component in the mirabilite gypsum can be effectively utilized in preparation; secondly, by adopting a hydrothermal method to produce gypsum whisker, not only can the industrial byproducts be effectively utilized and the problem of environmental pollution caused by stacking of waste materials can be solved, the purpose of green chemical industry can be achieved, and the national industrial policy can be completely met; the gypsum whisker belongs to an environment-friendly product with high added value, has wide market demand prospect and obvious economic benefit, has sufficient and low-cost raw material resources in the region after production, and is simple and feasible and easy to industrialize. Therefore, the research and final construction of the project in the area can certainly obtain huge economic and social benefits.
Compared with the prior art, the beneficial effect of this scheme:
1. the invention adopts a hydrothermal method, not only can effectively utilize industrial byproducts and solve the problem of environmental pollution caused by stacking of waste materials, but also achieves the purpose of green chemical industry and completely accords with the national industrial policy;
2. the whisker reaction kettle adopted by the invention is a spherical reaction kettle with a jacket and a stirring device which is a rotary slurry type; when the spherical reaction kettle with stirring is used for stirring, fluid media in the shell can obtain a more uniform flow field in the whole volume, dead angle-free and completely uniform mass transfer can be realized more easily, and meanwhile, the shaft rotating speed and shaft power can be reduced relatively; the slurry-spinning stirrer can ensure that the fluid in the reactor is mixed radially and axially, so that the reaction system is more uniform, and the aspect ratio of the finally obtained whisker is more uniform;
3. the lining material of the whisker reaction kettle adopted by the invention adopts the lining material of polytetrafluoroethylene filled graphite, and the lining material can effectively meet the corrosion resistance and heat transfer requirements of the reaction kettle;
4. the added modified stabilizer (coupling agent, fatty acid or fatty acid salt) forms hydrogen bond with hydroxyl on the surface of CSW, and then a partial covalent bond is formed by heating dehydration reaction, so that the surface of inorganic matters is covered by the coupling agent; the modified stabilizer is easy to spread on the surface of the whisker, can change the surface state of the whisker and change the contact angle of a solid-liquid interface of the whisker, thereby reducing the interface property difference between the whisker and a matrix;
5. the invention adopts a microwave drying mode, so that the dehydration rate in the drying process can reach about 98 percent, and the microwave drying time is only about 1/5 of the time of the common drying mode;
6. the invention adopts the technological process and optimized technological operation condition, so that the finally obtained calcium sulfate whisker has uniform morphology and proper length-diameter ratio (more than 50), the yield can reach 84%, and the whiteness is more than or equal to 96%.
Drawings
FIG. 1 is a flow chart of a process for preparing calcium sulfate whiskers in an embodiment of the invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, wherein it is to be understood that the illustrated embodiments are merely exemplary of some, but not all, of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The present invention will be described in detail with reference to examples.
Examples:
the scheme provided by the embodiment of the invention is as follows: a method for preparing calcium sulfate whisker from mirabilite gypsum, as shown in figure 1, comprises the following steps:
1. pretreatment of raw materials
The raw material mirabilite gypsum in the scheme of the embodiment contains 46% of water, 40% of semi-hydrated gypsum, 10% of mirabilite, 3% of dihydrate gypsum and 1% of stone slag, the raw material mirabilite gypsum is dissolved in water at normal temperature, stirred and led out of upper slurry, stirred and hydrolyzed, 0.6-1.6 mol/L of calcium water is added, diluted sulfuric acid is added after full stirring to adjust pH to 2-6, water is added for 2-3 times, and water is added after filtering to obtain a filter cake to prepare uniform gypsum slurry.
2. Preparation of whisker and modification by hydrothermal method
Adding 2% -10% of magnesium salt or copper salt crystal form growth promoter into the slurry obtained in the previous step, adding the slurry into a spherical kettle type reactor with a stirred jacket and a lining polytetrafluoroethylene-filled graphite anticorrosive lining material, heating to 120 ℃ to start timing reaction for 3.5 hours, pumping stabilizing and modifying agents (stearate, stearic acid, silane coupling agent, titanate coupling agent and accounting for 0.5% -4% of the mass of gypsum) by using a pressure pump, modifying for 0.5-2 hours, and then separating the solid and liquid of the slurry after reaction.
3. Drying of the product
Washing the filter cake obtained by solid-liquid separation with cold water, and drying for 20-60 min under the power of 500-1000W by microwaves.
In the above embodiments of the invention, the mirabilite gypsum is sodium sulfate extracted from a symbiotic ore of mirabilite and gypsum or a milky white waste residue from the production of mirabilite from glauber's salt. In recent years, the annual output of mirabilite in China is maintained to be about 1000 ten thousand tons, and the production of mirabilite gypsum in 2020 is about 400 ten thousand tons. The mirabilite gypsum is used as a raw material, and a hydrothermal method is adopted to produce gypsum whiskers, so that industrial byproducts can be effectively utilized, the problem of environmental pollution caused by stacking of waste materials is solved, the purpose of green chemical industry is achieved, and the national industrial policy is completely met; the gypsum whisker belongs to an environment-friendly product with high added value, has wide market demand prospect and obvious economic benefit, has sufficient and low-cost raw material resources in the region after production, and is simple and feasible and easy to industrialize. Therefore, the research and final construction of the project in the area can certainly obtain great economic and social benefits
In addition, compared with the method for preparing the calcium sulfate whisker in the prior art, the method in the prior art cannot fully utilize the useful components in the mirabilite gypsum because the cost of the mirabilite gypsum is very complex (comprising 46% of water, 40% of semi-hydrated gypsum, 10% of mirabilite, 3% of dihydrate gypsum, 1% of stone slag and the like), and the method in the invention adopts a method of prehydrolyzing the raw materials in the aspect of raw material pretreatment, and carries out the preparation process after prehydrolyzing the complex components in the raw materials, thereby being convenient for fully utilizing the useful components in the mirabilite gypsum. In addition, the invention adopts the technological process and optimized technological operation conditions, so that the finally obtained calcium sulfate whisker has uniform morphology and proper length-diameter ratio (more than 50), the yield can reach 84%, and the whiteness is more than or equal to 96%.
The above specific embodiments are provided for illustrative purposes only and are not intended to limit the invention, and modifications, no inventive contribution, will be made to the embodiments by those skilled in the art after having read the present specification, as long as they are within the scope of the patent statutes.
Claims (5)
1. A method for preparing calcium sulfate whisker from mirabilite gypsum is characterized by comprising the following steps: the method comprises the following steps:
s1, pretreatment of raw materials:
dissolving and stirring the raw material mirabilite gypsum in water at normal temperature, leading out upper slurry, stirring and hydrolyzing, adding calcium water, fully stirring, adding dilute sulfuric acid to adjust the PH, washing for 2-3 times, filtering to obtain a filter cake, and adding water to prepare uniform gypsum slurry;
s2, preparing whiskers by a hydrothermal method and modifying:
adding 2% -10% of magnesium salt or copper salt crystal form growth promoter into the gypsum slurry obtained in the step S1, adding the gypsum slurry into a spherical kettle type reactor, heating to 120 ℃, starting timing reaction for 3.5 hours, pumping a stabilizing and modifying agent by using a pressure pump, modifying for 0.5-2 hours, and then carrying out solid-liquid separation on the reacted slurry to obtain a filter cake;
s3, drying a product:
washing the filter cake obtained by solid-liquid separation in the step S2 with cold water, and drying for 20-60 min under the power of 500-1000W by microwaves to obtain a calcium sulfate whisker product.
2. A method for preparing calcium sulfate whisker from mirabilite gypsum as claimed in claim 1, wherein: the calcium water added in the step S1 is 0.6-1.6 mol/L.
3. A method for preparing calcium sulfate whisker from mirabilite gypsum as claimed in claim 1, wherein: in the step S1, dilute sulfuric acid is added to adjust the PH to 2-6.
4. A method for preparing calcium sulfate whisker from mirabilite gypsum as claimed in claim 1, wherein: the stabilizing and modifying agent in the step S2 comprises stearate, stearic acid, a silane coupling agent or a titanate coupling agent, and the stabilizing and modifying agent accounts for 0.5-4% of the mass of the gypsum.
5. A method for preparing calcium sulfate whisker from mirabilite gypsum as claimed in claim 1, wherein: the spherical kettle reactor in the step S1 is a spherical kettle reactor with a stirring jacket and an anticorrosive lining material lined with polytetrafluoroethylene filled graphite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310647791.6A CN116676672A (en) | 2023-06-02 | 2023-06-02 | Method for preparing calcium sulfate whisker from mirabilite gypsum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310647791.6A CN116676672A (en) | 2023-06-02 | 2023-06-02 | Method for preparing calcium sulfate whisker from mirabilite gypsum |
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| Publication Number | Publication Date |
|---|---|
| CN116676672A true CN116676672A (en) | 2023-09-01 |
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| CN202310647791.6A Pending CN116676672A (en) | 2023-06-02 | 2023-06-02 | Method for preparing calcium sulfate whisker from mirabilite gypsum |
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| Country | Link |
|---|---|
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2023
- 2023-06-02 CN CN202310647791.6A patent/CN116676672A/en active Pending
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