CN109280979B - Method for preparing semi-hydrated gypsum whisker - Google Patents
Method for preparing semi-hydrated gypsum whisker Download PDFInfo
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- CN109280979B CN109280979B CN201710589290.1A CN201710589290A CN109280979B CN 109280979 B CN109280979 B CN 109280979B CN 201710589290 A CN201710589290 A CN 201710589290A CN 109280979 B CN109280979 B CN 109280979B
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- 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
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- 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
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- 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
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Abstract
A method of making hemihydrate gypsum whiskers, comprising: selecting desulfurized gypsum as a raw material; drying the selected desulfurized gypsum to remove free water in the desulfurized gypsum; grinding the dried desulfurized gypsum into fine powder; screening the ground desulfurized gypsum to remove large-particle impurities in the desulfurized gypsum; adding the screened desulfurized gypsum into hydrochloric acid with a certain concentration, stirring and mixing to form slurry, and reacting the slurry at a certain temperature; after the normal-pressure hydrothermal reaction is finished, carrying out suction filtration on the slurry; washing a filter cake obtained after suction filtration by using an organic solvent; and drying the washed filter cake to obtain the hemihydrate gypsum whisker. The semi-hydrated gypsum crystal whisker prepared by the method has the length-diameter ratio of 300, has uniform diameter and does not have lattice defects such as dislocation, stacking and the like.
Description
Technical Field
The application relates to but is not limited to the field of inorganic chemical material preparation, in particular to but not limited to a method for preparing hemihydrate gypsum whiskers.
Background
The hemihydrate gypsum whisker is fibrous single crystal of hemihydrate calcium sulfate, has extremely high tensile strength, elastic modulus and dielectric strength, is simultaneously good in abrasion resistance, high temperature resistance, corrosion resistance and infrared reflectivity, easy for surface treatment, strong in affinity with high polymer, is an inorganic material with low price and extremely high comprehensive performance, can be applied to resin, rubber and coating as a reinforcing component, and has extremely wide development prospect.
The traditional preparation method of the semi-hydrated gypsum whisker is mainly an autoclaved hydrothermal method, and mainly comprises the steps of adding dihydrate gypsum into a salt solution with a crystal converter, and reacting at high pressure and high temperature.
Disclosure of Invention
The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.
The application provides a method for preparing semi-hydrated gypsum whiskers by utilizing desulfurized gypsum under the conditions of normal pressure and no crystal transformation agent.
Specifically, the application provides a method for preparing hemihydrate gypsum whiskers.
The method for preparing the hemihydrate gypsum whisker comprises the following steps:
taking materials: selecting desulfurized gypsum as a raw material;
and (3) drying: drying the selected desulfurized gypsum to remove free water in the desulfurized gypsum;
grinding: grinding the dried desulfurized gypsum into fine powder;
screening: screening the ground desulfurized gypsum to remove large-particle impurities in the desulfurized gypsum;
normal pressure hydrothermal reaction: adding the screened desulfurized gypsum into hydrochloric acid with a certain concentration, stirring and mixing to form slurry, and reacting the slurry at a certain temperature;
and (3) suction filtration: after the normal-pressure hydrothermal reaction is finished, carrying out suction filtration on the slurry;
washing: washing a filter cake obtained after suction filtration by using an organic solvent;
and (3) drying: and drying the washed filter cake to obtain the hemihydrate gypsum whisker.
In an embodiment of the present application, the drying of the selected desulfurized gypsum may be drying the selected desulfurized gypsum at 40 to 50 ℃ for 4 to 6 hours.
In embodiments of the present application, the sieving may be a 100-mesh and 300-mesh sieving.
In an embodiment of the present application, the concentration of the hydrochloric acid may be 2 mol/L.
In the embodiment of the application, the mass ratio of the screened desulfurized gypsum to the hydrochloric acid can be 1 (8-11).
In the embodiment of the present application, the reaction temperature of the atmospheric hydrothermal reaction may be 93 to 96 ℃, and the reaction time may be 6 to 8 hours.
In an embodiment of the present application, the organic solvent may be absolute ethanol.
In embodiments of the present application, the filter cake may be dried at a temperature of 93 to 96 ℃ for a time of 4 to 6 hours.
The method can realize the preparation of the semi-hydrated gypsum whisker under the conditions of normal pressure and no crystal transformation agent, the length-diameter ratio of the prepared semi-hydrated gypsum whisker reaches 300, the semi-hydrated gypsum whisker has uniform diameter, HRTEM images show that the semi-hydrated gypsum whisker does not have lattice defects such as dislocation, stacking and the like, the control of the crystal phase and the morphology of the product is realized, and guidance is provided for the preparation method of the semi-hydrated gypsum whisker in the future and the cyclic utilization of industrial solid waste desulfurized gypsum.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the claimed subject matter and are incorporated in and constitute a part of this specification, illustrate embodiments of the subject matter and together with the description serve to explain the principles of the subject matter and not to limit the subject matter.
FIG. 1 is an XRD pattern of a desulfurized gypsum feedstock.
FIGS. 2a) -b) are SEM images of desulfurized gypsum feedstock at different magnifications.
Figure 3 is an XRD pattern of the hemihydrate gypsum whiskers prepared in example 1 of the present application.
Figure 4 is an SEM image of gypsum hemihydrate whiskers prepared in example 1 of the present application.
Figure 5 is a TEM image of hemihydrate gypsum whiskers prepared in example 1 of the present application.
Figure 6 is an HRTEM of hemihydrate gypsum whiskers prepared in example 1 of the present application.
Detailed Description
To make the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.
The desulfurized gypsum used in the following examples was obtained from Ningxia Zhongwei power plants, and other raw materials and reagents, unless otherwise specified, were all common commercial products.
Example 1:
A. selecting raw materials: 2g of desulfurized gypsum is selected as a raw material.
B. Drying of raw materials: and (3) feeding the selected desulfurized gypsum into a drying oven, adjusting the temperature of the drying oven to 40 ℃, drying for 4 hours, and removing free water in the raw materials.
C. Grinding raw materials: and (3) grinding the dried desulfurized gypsum into fine powder in a mortar.
D. Screening raw materials: and sieving the ground desulfurized gypsum through a 230-mesh sieve to remove large-particle impurities.
E. Normal pressure hydrothermal reaction of raw materials: 1g of desulfurized gypsum obtained by sieving was weighed out and added to 10ml of 2mol/L hydrochloric acid (density: about 1.03g/ml) and reacted at 93 ℃ for 6 hours.
F. And (3) suction filtration: and (4) carrying out rapid suction filtration on the slurry after reaction to obtain a white filter cake.
G. Washing: and washing the filter cake obtained after suction filtration by using absolute ethyl alcohol at room temperature.
H. And (3) drying: and (3) feeding the washed filter cake into a drying oven, adjusting the temperature of the drying oven to 93 ℃, and drying for 4 hours to obtain the hemihydrate gypsum whisker.
Example 2:
A. selecting raw materials: 4g of desulfurized gypsum is selected as a raw material.
B. Drying of raw materials: and (3) feeding the selected desulfurized gypsum into a drying oven, adjusting the temperature of the drying oven to 45 ℃, drying for 5 hours, and removing free water in the raw materials.
C. Grinding raw materials: and (3) grinding the dried desulfurized gypsum into fine powder in a mortar.
D. Screening raw materials: and sieving the ground desulfurized gypsum by a 240-mesh sieve to remove large-particle impurities.
E. Normal pressure hydrothermal reaction of raw materials: 3g of desulfurized gypsum obtained by sieving was weighed out, added to 26ml of 2mol/L hydrochloric acid, and reacted at 95 ℃ for 7 hours.
F. And (3) suction filtration: and (4) carrying out rapid suction filtration on the slurry after reaction to obtain a white filter cake.
G. Washing: and washing the filter cake obtained after suction filtration by using absolute ethyl alcohol at room temperature.
H. And (3) drying: and (3) feeding the washed filter cake into a drying oven, adjusting the temperature of the drying oven to 95 ℃, and drying for 5h to obtain the hemihydrate gypsum whisker.
Example 3:
A. selecting raw materials: 10g of desulfurized gypsum is selected as a raw material.
B. Drying of raw materials: and (3) feeding the selected desulfurized gypsum into a drying oven, adjusting the temperature of the drying oven to 50 ℃, drying for 6 hours, and removing free water in the raw materials.
C. Grinding raw materials: and (3) grinding the dried desulfurized gypsum into fine powder in a mortar.
D. Screening raw materials: and sieving the ground desulfurized gypsum by a 240-mesh sieve to remove large-particle impurities.
E. Normal pressure hydrothermal reaction of raw materials: 8g of desulfurized gypsum obtained by sieving was weighed out, added to 80ml of 2mol/L hydrochloric acid, and reacted at 96 ℃ for 8 hours.
F. And (3) suction filtration: and (4) carrying out rapid suction filtration on the slurry after reaction to obtain a white filter cake.
G. Washing: and washing the filter cake obtained after suction filtration by using absolute ethyl alcohol at room temperature.
H. And (3) drying: and (3) feeding the washed filter cake into a drying oven, adjusting the temperature of the drying oven to 96 ℃, and drying for 6h to obtain the hemihydrate gypsum whisker.
Test example
1. The XRD patterns of the desulfurized gypsum raw material and the hemihydrate gypsum whisker prepared in the example 1 of the application are respectively tested by using an X-ray diffraction analyzer of the SHIMADZU XRD-7000 type.
And (3) testing conditions are as follows: the Cu target Kalpha ray source has the tube voltage of 40kV, the tube current of 30mA and the scanning speed of 2 degrees/min. The test results are shown in FIGS. 1 and 3.
Comparing fig. 1 and fig. 3, the change of the characteristic peak position of XRD shows that the phase of desulfurized gypsum is changed from calcium sulfate dihydrate to calcium sulfate hemihydrate after conversion by the method described in example 1 of the present application.
2. SEM images of the desulfurized gypsum raw material and the hemihydrate gypsum whiskers prepared in example 1 of the present application at different magnifications were respectively tested by using a S-4800 Field Emission Scanning Electron Microscope (FESEM).
And (3) testing conditions are as follows: the acceleration voltage was 15 kV. See fig. 2 and 4 for test results.
Comparing fig. 2 and fig. 4, it can be seen that the micro-morphology of the desulfurized gypsum is changed from large particle to fiber after being transformed by the method described in example 1 of the present application.
3. TEM images of the hemihydrate gypsum whiskers prepared in example 1 of the present application were tested by a JEM-2010 transmission electron microscope. The test results are shown in FIG. 5.
As can be seen from fig. 5, the hemihydrate gypsum whiskers prepared in example 1 of the present application have a uniform diameter.
The prepared hemihydrate gypsum whisker has the average length of about 500-600 μm, the average diameter of about 1-2 μm and the length-diameter ratio of about 300.
4. HRTEM image of the hemihydrate gypsum whisker prepared in example 1 of the present application was tested by JEM-2010 transmission electron microscope. The test results are shown in FIG. 6.
As can be seen from FIG. 6, the gypsum hemihydrate whiskers prepared in example 1 of the present application have clear lattice stripes, no lattice defects such as dislocation and stacking exist, the lattice spacing is 0.341nm, and the crystal lattice spacing corresponds to the (020) crystal plane of the calcium sulfate hemihydrate.
Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.
Claims (5)
1. A method of making hemihydrate gypsum whiskers, comprising the steps of:
taking materials: selecting desulfurized gypsum as a raw material;
and (3) drying: drying the selected desulfurized gypsum to remove free water in the desulfurized gypsum;
grinding: grinding the dried desulfurized gypsum into fine powder;
screening: screening the ground desulfurized gypsum to remove large-particle impurities in the desulfurized gypsum;
normal pressure hydrothermal reaction: adding the screened desulfurized gypsum into hydrochloric acid with a certain concentration, stirring and mixing to form slurry, and reacting the slurry at a certain temperature;
and (3) suction filtration: after the normal-pressure hydrothermal reaction is finished, carrying out suction filtration on the slurry;
washing: washing a filter cake obtained after suction filtration by using an organic solvent;
and (3) drying: drying the washed filter cake to obtain the hemihydrate gypsum whisker;
the reaction temperature of the normal pressure hydrothermal reaction is 93-96 ℃;
the concentration of the hydrochloric acid is 2 mol/L;
the mass ratio of the screened desulfurized gypsum to the hydrochloric acid is 1: 8-11;
the drying temperature of the filter cake is 93-96 ℃, and the drying time is 4-6 h.
2. The method of claim 1, wherein the drying the selected desulfurized gypsum is carried out by drying the selected desulfurized gypsum at 40-50 ℃ for 4-6 hours.
3. The method as claimed in claim 1, wherein the sieving is performed with a 100-mesh and 300-mesh sieve.
4. The method according to claim 1, wherein the reaction time of the atmospheric hydrothermal reaction is 6-8 h.
5. The method of claim 1, wherein the organic solvent is absolute ethanol.
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| CN201710589290.1A CN109280979B (en) | 2017-07-19 | 2017-07-19 | Method for preparing semi-hydrated gypsum whisker |
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| CN201710589290.1A CN109280979B (en) | 2017-07-19 | 2017-07-19 | Method for preparing semi-hydrated gypsum whisker |
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| CN111607827B (en) * | 2019-07-16 | 2022-01-07 | 北新集团建材股份有限公司 | Post-treatment method of calcium sulfate whisker |
| CN112760716B (en) * | 2021-01-15 | 2024-05-24 | 海南蓝岛环保产业股份有限公司 | Recycling treatment method of phosphogypsum |
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| DE1238374B (en) * | 1965-04-24 | 1967-04-06 | Giulini Ges Mit Beschraenkter | Process for the production of alpha calcium sulfate hemihydrate |
| CN100382873C (en) * | 2003-06-06 | 2008-04-23 | 浙江大学 | Techlogogy for making alpha semi-water desulfur gypsum using normal pressure salt solution method |
| CN1245331C (en) * | 2004-04-20 | 2006-03-15 | 浙江大学 | Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure |
| CN101113084A (en) * | 2007-07-06 | 2008-01-30 | 天津大学 | Method for preparing shape-controlled alpha-semi-hydrated gypsum by using flue gas desulfurized gypsum |
| CN101182150A (en) * | 2007-11-09 | 2008-05-21 | 浙江大学 | Industrial crystallization technique for preparing alpha-semi-hydrated gypsum directly by desulfurized gypsum slurry |
| CN101381209B (en) * | 2008-09-28 | 2011-04-27 | 浙江大学 | Method for transforming desulfating gypsum to alpha-half hydrated gypsum in atmospheric KCl solution |
| CN101870494A (en) * | 2010-06-12 | 2010-10-27 | 上海大学 | Method for recrystallizing and purifying desulphurized gypsum |
| CN102352535B (en) * | 2011-09-22 | 2014-01-29 | 东莞上海大学纳米技术研究院 | Method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure |
| CN102515593A (en) * | 2011-12-25 | 2012-06-27 | 河南佰利联化学股份有限公司 | Method for producing semi-hydrated gypsum by using salt solution |
| CN102925956B (en) * | 2012-11-26 | 2014-12-03 | 武汉科技大学 | Method for preparing calcium sulfate hemihydrate whiskers by taking ardealite as main raw material |
| CN103924301A (en) * | 2014-04-24 | 2014-07-16 | 内蒙古工业大学 | Method for preparing ultra-fine calcium sulfate whisker from flue gas desulfurization gypsum |
| CN106480507A (en) * | 2016-11-15 | 2017-03-08 | 曲靖师范学院 | A kind of new technology of ardealite preparation low cost hemihydrate calcium sulfate crystal whisker |
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