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Preparation method of needle-like nano calcium carbonate

A nano-calcium carbonate and needle-shaped technology, which is applied in the field of preparation of needle-shaped nano-calcium carbonate powder, can solve the problems that the needle-shaped calcium carbonate orientation and reinforcement effect cannot be achieved, the proportion of needle-shaped products decreases, and the agglomeration is serious. Easy process adjustment and control, good dispersibility, good dispersibility effect

Inactive Publication Date: 2012-03-14
SHANGHAI HUAMING HI TECH GRP
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method needs to strictly control the reaction process conditions, otherwise the proportion of acicular products will be greatly reduced; the acicular calcium carbonate particle size prepared by this method is too small, the specific surface area is large, the product has poor dispersion performance and serious agglomeration
At the same time, because of its small particle size, its radial strength is low, and it is easy to break during subsequent processing and application, resulting in a decrease in the actual aspect ratio, and the orientation and reinforcement effect of acicular calcium carbonate on the material cannot be achieved.

Method used

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  • Preparation method of needle-like nano calcium carbonate
  • Preparation method of needle-like nano calcium carbonate
  • Preparation method of needle-like nano calcium carbonate

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Adding 5 liters of calcium hydroxide mass concentration in 7 liters of stirred reactor is 10% initial temperature of refined milk of lime at 26°C, add 20.3g ethylenediaminetetraacetic acid and 16.9g aluminum chloride, after stirring, pass Inject carbon dioxide volume concentration of 98% CO 2 -N 2 The carbonization reaction of the mixed gas starts, and the gas flow rate is 60L / h;

[0027] When the carbonization reaches a pH of 6.8, continue aeration for 15 minutes, stop aeration carbonization, and the final temperature of the reaction system reaches 49°C.

[0028] The resulting product was observed with a scanning electron microscope, and its appearance was needle-shaped, with an aspect ratio of 35, a particle size of 22nm, and a narrow particle size distribution range; its specific surface area was 76.4m 2 / g, XRD analysis is calcite crystal form.

Embodiment 2

[0030] Add 5 liters of refined milk of lime with a mass concentration of calcium hydroxide of 14% and an initial temperature of 37°C in a 7-liter stirred reactor, add 13.5 g of citric acid and 7.4 g of zinc sulfate at the same time, and after stirring, pass in a volume of carbon dioxide Concentration of 33% CO 2 -N 2 Mixed gas for carbonization reaction, the gas flow rate is 200L / h;

[0031] When the carbonization reaches a pH of 7.0, continue aeration for 20 minutes, stop the aeration carbonization, and the final temperature of the reaction system reaches 59°C.

[0032] The resulting product was filtered and dried, and observed with a scanning electron microscope. Its appearance was needle-shaped, the aspect ratio was 10, the particle size was 45nm, and the particle size distribution range was narrow; its specific surface area was measured as 49.0m 2 / g, XRD analysis is calcite crystal form.

Embodiment 3

[0034] In a bubbling carbonization tower of 20 liters (inner diameter 140mm, height-to-diameter ratio 8: 1), add 15 liters of calcium hydroxide mass concentration and be the refined milk of lime of 26 ℃ with the initial temperature of 8%, add 24.3g ethylenediamine simultaneously Tetraacetic acid and 21.1g aluminum sulfate, after stirring evenly, pass into the CO that the volume concentration of carbon dioxide is 50% 2 -N 2 The carbonization reaction of the mixed gas starts, and the gas flow rate is 610L / h;

[0035] When the carbonization reaches a pH of 6.8, continue aeration for 30 minutes, stop the aeration carbonization, and the final temperature of the reaction system reaches 47°C.

[0036] The resulting product was filtered and dried, and observed with a scanning electron microscope. Its appearance was needle-shaped, the particle diameter was 34nm, the aspect ratio was 13, and the particle size distribution range was narrow; its specific surface area was 52.3m 2 / g, XRD...

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Abstract

The invention provides a preparation method of needle-like nano calcium carbonate. The method comprises the following steps: (1) adding a composite crystal form control agent in a calcium hydroxide suspension, wherein the composite crystal form control agent comprises an organic acid and water-soluble chloride or sulfate; (2) introducing a gas containing carbon dioxide in the suspension for carbonization reaction; (3) when the pH value of the suspension is reduced to 6.5-7.0, further introducing gas for 15-30 minutes, and then finishing the carbonization reaction. Compared with the existing technical scheme, the needle-like nano calcium carbonate product obtained by the preparation method has more appropriate average particle diameter, controllable particle diameter and good dispersibility; and the product dose not break under the ordinary grinding strength; and the production process is easy to regulate and control.

Description

technical field [0001] The invention relates to a preparation method of acicular nanometer calcium carbonate powder. Background technique [0002] Calcium carbonate is an important inorganic filler, widely used in rubber, plastics, papermaking, coatings, inks and other fields. Calcium carbonate has various shapes such as spindle shape, cubic shape, spherical shape, needle shape, chain shape, flake shape, etc. The microscopic shape of calcium carbonate determines the application field and function of its products. [0003] As the name implies, the appearance of needle-shaped nano-calcium carbonate is similar to needle-shaped, that is, it has a large aspect ratio, and its radial size (hereinafter referred to as the particle size) is nano-scale calcium carbonate. The highly anisotropic shape of needle-like nano-calcium carbonate can be added to rubber, plastic, paper and other products as a functional filler, which can effectively improve the mechanical properties of its orien...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18
Inventor 陈雪梅叶育倩李鹏吴秋芳马新胜
Owner SHANGHAI HUAMING HI TECH GRP
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