CN112011830A - Method for preparing anhydrous calcium sulfate nanowhiskers at room temperature - Google Patents
Method for preparing anhydrous calcium sulfate nanowhiskers at room temperature Download PDFInfo
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- CN112011830A CN112011830A CN202010895418.9A CN202010895418A CN112011830A CN 112011830 A CN112011830 A CN 112011830A CN 202010895418 A CN202010895418 A CN 202010895418A CN 112011830 A CN112011830 A CN 112011830A
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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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
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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
- C30B7/14—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions the crystallising materials being formed by chemical reactions in the solution
Abstract
The invention provides a method for preparing anhydrous calcium sulfate nano whiskers at room temperature, which comprises the following steps: (1) adding a calcium acetate solution into an organic solvent, adding a surfactant, and stirring until the reaction is complete to obtain a mixed solution A; (2) adding dilute sulfuric acid into an organic solvent to obtain a mixed solution B; (3) dropwise adding the mixed solution A into the mixed solution B, and stirring at room temperature for reaction to obtain a mixed solution C; (4) and washing, centrifuging and freeze-drying the mixed solution C to obtain the anhydrous calcium sulfate nano whisker. The method provided by the invention can be carried out at room temperature, has the advantages of simple process, low cost, short preparation time, energy conservation, consumption reduction, low equipment threshold, environmental protection, contribution to cost control and capability of being used for industrial production. The prepared crystal is nano-scale, has higher length-diameter ratio which can reach 55. The invention provides a new idea for preparing anhydrous calcium sulfate crystals, and has a wide application prospect.
Description
Technical Field
The invention belongs to the technical field of green sustainable preparation, and particularly relates to a preparation method for preparing anhydrous calcium sulfate nano whisker at room temperature.
Background
The anhydrous whisker calcium sulfate is a sub-nano fiber material with complete appearance, large length-diameter ratio, large specific surface area and uniform cross section, is a modifier with good performance, but is limited by the current preparation method, and the mass of the commercially available calcium sulfate whiskers is uneven, so that the large-range application of the calcium sulfate is limited.
The traditional method for preparing calcium sulfate crystal whisker at home and abroad is a preparation process of a normal pressure acidification method, a hydrothermal synthesis method, an ion exchange method and a microemulsion method. The hydrothermal synthesis method effectively solves the problem that calcium sulfate is difficult to dissolve, reaction synthesis and crystallization in a kettle are completed in one step, the shape is complete in production, particles are uniform, and less calcium sulfate whiskers are agglomerated. The reaction period is long, the energy consumption is high, the danger coefficient is high, and the experimental conditions can not be changed according to experimental phenomena in the reaction process. The ion exchange method is directly dried without washing, the product has complete shape and high purity, but the method has stronger selectivity and only takes effect on specific ions, and the solution in the production process causes the reduction of the ion solubility, thereby influencing the production efficiency. The ion exchange resin is organic and is easy to be affected by external mechanical, oxidation and other effects, so that the effective components of the resin flow out, and the application in industry is difficult.
In the method for preparing the calcium sulfate whisker by using the natural gypsum, the patent CN109695052A purifies and purifies the natural gypsum by a chemical method to obtain pure calcium sulfate, and the pure calcium sulfate is synthesized by a hydrothermal method. However, the lack of natural gypsum resource is a waste of resources, and the hydrothermal synthesis method is carried out at high temperature and high pressure, so that the high pressure resistance and the tightness of equipment are strict, the size of a reaction device is limited, the productivity is low, and the large-scale production cannot be realized.
Patent CN10456180A discloses a method for preparing calcium sulfate whisker from phosphogypsum, in which solid waste residues are used as raw materials, crystals with the diameter of 1-4 um and the length of 50-200 um are prepared by synthesis reaction, heating, filtering and dissolving, hot filtering and cooling crystallization, the diameter and the length of the crystals are controllable, and industrial byproduct gypsum is fully utilized to cure waste. The phosphogypsum is not treated, the calcium sulfate whisker is not modified, and the length-diameter ratio of the prepared calcium sulfate whisker is not large.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for preparing anhydrous calcium sulfate nano whiskers at room temperature. According to the invention, the raw materials are dissolved by selecting the organic solvent, and then the preparation process is optimized, so that the anhydrous calcium sulfate nano crystal whisker is prepared at room temperature, the crystal morphology can be well controlled, the process steps are simple, the cost is low, the equipment requirement is low, the preparation time is short, the energy is saved, the consumption is reduced, and the preparation method is green and environment-friendly. The prepared calcium sulfate is nano-scale, and has high length-diameter ratio.
According to the method provided by the invention, n-hexane, cyclohexane, chloroform or ethyl acetate is selected as an organic solvent, the organic solvent and a water system are matched with a surfactant to form a micro-emulsion environment, and a calcium sulfate product with a smaller size is conveniently formed in a micro-environment through different dissolution potential energies of products in different solvents, and the calcium sulfate product can also play a role of a dispersing agent, so that the whole reaction system is dispersed more uniformly. The organic solvent can be effectively combined with the surfactant, so that the surfactant has a good solubilizing effect, the organic solvent and the surfactant synergistically enhance the dispersing effect, the uniformity of a reaction system is further improved, and the product quality is finally improved. In addition, the organic solvent can be recycled, which causes secondary pollution,
the technical scheme provided by the invention is as follows:
a method for preparing anhydrous calcium sulfate nanowhiskers at room temperature comprises the following steps:
(1) adding a calcium acetate solution into an organic solvent, adding a surfactant, and stirring until the reaction is complete to obtain a mixed solution A;
(2) adding dilute sulfuric acid into an organic solvent to obtain a mixed solution B;
(3) dropwise adding the mixed solution A into the mixed solution B, and stirring at room temperature for reaction to obtain a mixed solution C;
(4) and washing, centrifuging and freeze-drying the mixed solution C to obtain the anhydrous calcium sulfate nano whisker.
Further, the calcium acetate solution in the step (1) is prepared by reacting high-calcium waste stone powder, calcium carbonate or calcium hydroxide with anhydrous acetic acid.
Further, the concentration of the calcium acetate solution in the step (1) is 25-35 g/L.
Further, the organic solvent in the steps (1) and (2) is selected from one of n-hexane, cyclohexane, chloroform or ethyl acetate. The organic solvents in the steps (1) and (2) are consistent in type, so that the uniformity of the system is ensured.
Further, in the step (1), the surfactant is selected from phospholipid, choline protein, sodium stearyl sulfate or sodium stearate.
Further, the mass ratio of the calcium acetate solution, the organic solvent and the surfactant in the step (1) is 20-40:50: 2-4.
Further, the concentration of the dilute sulfuric acid in the step (2) is 15-25 wt%.
Further, the mass ratio of the dilute sulfuric acid to the organic solvent in the step (2) is 25-35: 50.
Further, the mass ratio of the mixed liquor A to the mixed liquor B in the step (3) is 72-94: 75-85.
Further, the pH value of the reaction system in the step (3) is 2-4.
Compared with the prior art, the invention has the following beneficial effects:
(1) the method provided by the invention can be carried out at room temperature, and has the advantages of simple process, low cost, short preparation time, energy conservation, consumption reduction, low equipment threshold, greenness, environmental protection, contribution to cost control and capability of being used for industrial production;
(2) according to the invention, the crystal morphology can be effectively improved by utilizing the organic solvent and the combination process optimization, and the organic solvent and the surfactant can effectively remove impurities and simultaneously synergistically improve the dispersibility of system components, so that the uniformity of the solution is improved, and the uniformity and the quality of the product are improved;
(3) the prepared crystal is nano-scale, has higher length-diameter ratio which can reach 55;
(4) provides a new idea for preparing the anhydrous calcium sulfate crystal and has a larger application prospect.
Drawings
FIG. 1 is an SEM image of anhydrous calcium sulfate crystals prepared according to the present invention.
Detailed Description
The technical solution of the present invention is further defined below with reference to the specific embodiments, but the scope of the claims is not limited to the description.
A method for preparing anhydrous calcium sulfate nanowhiskers at room temperature comprises the following steps:
(1) adding a calcium acetate solution into an organic solvent, adding a surfactant, and stirring until the reaction is complete to obtain a mixed solution A;
(2) adding dilute sulfuric acid into an organic solvent to obtain a mixed solution B;
(3) dropwise adding the mixed solution A into the mixed solution B, and stirring at room temperature for reaction to obtain a mixed solution C;
(4) and washing, centrifuging and freeze-drying the mixed solution C to obtain the anhydrous calcium sulfate nano whisker.
Further, the calcium acetate solution in the step (1) is prepared by reacting high-calcium waste stone powder, calcium carbonate or calcium hydroxide with anhydrous acetic acid.
Further, the concentration of the calcium acetate solution in the step (1) is 25-35 g/L.
Further, the organic solvent in the steps (1) and (2) is selected from one of n-hexane, cyclohexane, chloroform or ethyl acetate.
Further, in the step (1), the surfactant is selected from phospholipid, choline protein, sodium stearyl sulfate or sodium stearate.
Further, the mass ratio of the calcium acetate solution, the organic solvent and the surfactant in the step (1) is 20-40:50: 2-4.
Further, the concentration of the dilute sulfuric acid in the step (2) is 15-25 wt%.
Further, the mass ratio of the dilute sulfuric acid to the organic solvent in the step (2) is 25-35: 50.
Further, the mass ratio of the mixed liquor A to the mixed liquor B in the step (3) is 72-94: 75-85.
Further, the pH value of the reaction system in the step (3) is 2-4.
In the following examples, the parts are by mass unless otherwise specified.
Example 1
The preparation steps are as follows:
(1) adding 20 parts of high-concentration calcium acetate solution into 50 parts of cyclohexane, adding 2 parts of choline protein, and mechanically stirring for 1 hour to fully react to obtain a mixed solution A.
(2) 25 parts of dilute sulfuric acid having a concentration of 20% by weight was added to 50 parts of cyclohexane to obtain a mixed solution B.
(3) Dropwise adding the mixed solution A into the mixed solution B, controlling the pH to be 2-4, and stirring at room temperature for 0.5 hour to obtain a mixed solution C.
(4) And washing and centrifuging the mixed solution C for 3 times by using ethanol, and then freeze-drying to obtain the anhydrous calcium sulfate nanowhisker.
Example 2
The preparation steps are as follows:
(1) adding 25 parts of high-concentration calcium acetate solution into 50 parts of cyclohexane, adding 2 parts of choline protein, and mechanically stirring for 1.2 hours to fully react to obtain a mixed solution A.
(2) 28 parts of 20% by weight dilute sulfuric acid was added to 50 parts of cyclohexane to obtain a mixed solution B.
(3) Dropwise adding the mixed solution A into the mixed solution B, controlling the pH to be 2-4, and stirring at room temperature for 0.7 hour to obtain a mixed solution C.
(4) And washing and centrifuging the mixed solution C for 3 times by using ethanol, and then freeze-drying to obtain the anhydrous calcium sulfate nanowhisker.
Example 3
The preparation steps are as follows:
(1) 30 parts of high-concentration calcium acetate solution is added into 50 parts of cyclohexane, 3 parts of choline protein is added, and the mixture is mechanically stirred for 1.5 hours to fully react to obtain a mixed solution A.
(2) 30 parts of 20% by weight dilute sulfuric acid was added to 50 parts of cyclohexane to obtain a mixed solution B.
(3) Dropwise adding the mixed solution A into the mixed solution B, controlling the pH to be 2-4, and stirring at room temperature for 0.8 hour to obtain a mixed solution C.
(4) And washing and centrifuging the mixed solution C for 3 times by using ethanol, and then freeze-drying to obtain the anhydrous calcium sulfate nanowhisker.
Example 4
The preparation steps are as follows:
(1) adding 35 parts of high-concentration calcium acetate solution into 50 parts of cyclohexane, adding 3 parts of choline protein, and mechanically stirring for 1.8 hours to fully react to obtain a mixed solution A.
(2) To 50 parts of cyclohexane was added 33 parts of 20 wt% dilute sulfuric acid to obtain a mixed solution B.
(3) Dropwise adding the mixed solution A into the mixed solution B, controlling the pH to be 2-4, and stirring at room temperature for 0.9 hour to obtain a mixed solution C.
(4) And washing and centrifuging the mixed solution C for 3 times by using ethanol, and then freeze-drying to obtain the anhydrous calcium sulfate nanowhisker.
Example 5
The preparation steps are as follows:
(1) 40 parts of high-concentration calcium acetate solution is added into 50 parts of cyclohexane, 4 parts of choline protein is added, and the mixture is mechanically stirred for 2 hours to fully react to obtain a mixed solution A.
(2) 35 parts of dilute 20 wt% sulfuric acid concentration was added to 50 parts of cyclohexane to obtain a mixed solution B.
(3) Dropwise adding the mixed solution A into the mixed solution B, controlling the pH to be 2-4, and stirring at room temperature for 1 hour to obtain a mixed solution C.
(4) And washing and centrifuging the mixed solution C for 3 times by using ethanol, and then freeze-drying to obtain the anhydrous calcium sulfate nanowhisker.
The parameters of the anhydrous calcium sulfate whiskers prepared in each example are compared and shown in table 1:
TABLE 1
As can be seen from table 1: with the increase of the concentration of calcium acetate and the unchanged concentration of sulfuric acid, the nano diameter is increased and the conversion rate is also increased, but with the increase of the dosage of sulfuric acid, the nano diameter is reduced on the contrary, and with the reduction of the conversion rate, the optimum amount of the nano diameter and the conversion rate is shown, when the concentration of calcium acetate is 35g and the concentration of sulfuric acid is 30g, the nano diameter is 4um, the conversion rate of phosphogypsum reaches 80%, and the effect is obviously better than that of other groups.
Fig. 1 is an SEM image of the anhydrous calcium sulfate whiskers prepared, from which it can be seen that: the diameter of the prepared nano whisker is 2-5um, and the length-diameter ratio is more than 55.
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 modification, equivalent replacement, and improvement made by those skilled in the art within the technical scope of the present invention should be included in the scope of the present invention.
Claims (10)
1. A method for preparing anhydrous calcium sulfate nano whiskers at room temperature is characterized by comprising the following steps:
(1) adding a calcium acetate solution into an organic solvent, adding a surfactant, and stirring until the reaction is complete to obtain a mixed solution A;
(2) adding dilute sulfuric acid into an organic solvent to obtain a mixed solution B;
(3) dropwise adding the mixed solution A into the mixed solution B, and stirring at room temperature for reaction to obtain a mixed solution C;
(4) and washing, centrifuging and freeze-drying the mixed solution C to obtain the anhydrous calcium sulfate nano whisker.
2. The method of claim 1, wherein: the calcium acetate solution in the step (1) is prepared by reacting high-calcium waste stone powder, calcium carbonate or calcium hydroxide with anhydrous acetic acid.
3. The method of claim 1, wherein: the concentration of the calcium acetate solution in the step (1) is 25-35 g/L.
4. The method of claim 1, wherein: the organic solvent in the steps (1) and (2) is selected from one of n-hexane, cyclohexane, chloroform or ethyl acetate.
5. The method of claim 1, wherein: the surfactant in the step (1) is selected from phospholipid, choline protein, sodium octadecanesulfate or sodium stearate.
6. The method of claim 1, wherein: the mass ratio of the calcium acetate solution, the organic solvent and the surfactant in the step (1) is 20-40:50: 2-4.
7. The method of claim 1, wherein: the concentration of the dilute sulfuric acid in the step (2) is 15-25 wt%.
8. The method of claim 1, wherein: the mass ratio of the dilute sulfuric acid to the organic solvent in the step (2) is 25-35: 50.
9. The method of claim 1, wherein: the mass ratio of the mixed liquor A to the mixed liquor B in the step (3) is 72-94: 75-85.
10. The method of claim 1, wherein: the pH value in the reaction system of the step (3) is 2-4.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102965722A (en) * | 2012-10-31 | 2013-03-13 | 铜陵市祥英锌业有限公司 | Microemulsion method for producing whisker calcium sulfate with by-product sodium sulfate solution |
| CN106745161A (en) * | 2017-01-17 | 2017-05-31 | 厦门大学 | A kind of method that nanometer calcium sulfate and calcium sulfate crystal whiskers are prepared in alcohol water mixed system |
| CN106745154A (en) * | 2016-11-24 | 2017-05-31 | 上海大学 | A kind of method that high length-diameter ratio calcium sulfate nano wire is prepared under cryogenic conditions |
| CN110835780A (en) * | 2019-10-28 | 2020-02-25 | 昆明理工大学 | Method for preparing nanometer α type calcium sulfate hemihydrate crystal whisker from phosphogypsum in reverse microemulsion system |
-
2020
- 2020-08-31 CN CN202010895418.9A patent/CN112011830A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102965722A (en) * | 2012-10-31 | 2013-03-13 | 铜陵市祥英锌业有限公司 | Microemulsion method for producing whisker calcium sulfate with by-product sodium sulfate solution |
| CN106745154A (en) * | 2016-11-24 | 2017-05-31 | 上海大学 | A kind of method that high length-diameter ratio calcium sulfate nano wire is prepared under cryogenic conditions |
| CN106745161A (en) * | 2017-01-17 | 2017-05-31 | 厦门大学 | A kind of method that nanometer calcium sulfate and calcium sulfate crystal whiskers are prepared in alcohol water mixed system |
| CN110835780A (en) * | 2019-10-28 | 2020-02-25 | 昆明理工大学 | Method for preparing nanometer α type calcium sulfate hemihydrate crystal whisker from phosphogypsum in reverse microemulsion system |
Non-Patent Citations (2)
| Title |
|---|
| SHUN CHEN等: "Microemulsion synthesis of anhydrous calcium sulfate nanowhiskers with calcium acetate solution and its surface structure stable and crystal phase evolution after modification", 《JOURNAL OF NANOPARTICLE RESEARCH》 * |
| 鄢海燕等: "《高职高专"十三五"规划教材 药剂学 第2版》", 31 January 2018, 江苏科学技术出版社 * |
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