Precipitated calcium carbonate seed crystal containing aragonite crystal phase and preparation method thereof

A technology for precipitating calcium carbonate and crystal seeds, applied in the direction of calcium carbonate/strontium/barium, etc., can solve the problems of high cost, unsuitability, rising production cost, etc., and achieve the effect of narrow size distribution

Active Publication Date: 2017-10-17
建德华明科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

with MgCl 2 The main disadvantage of the preparation process for additives is that MgCl 2 The consumption is large, the cost is high, and the process requirements are complicated
[0005] There are several problems with using strontium compounds as additives: one is the high price of strontium compounds, which leads to an increase in production costs; the other is the complex mechanism of strontium, which requires a high carbonization process
As disclosed in Japanese Patent Laid-Open No. 59-223225, compounds such as strontium halogen compounds, oxides, oxy-acid salts, and organic acid salts are used as additives to prepare calcium carbonate containing aragonite crystal phases. The calcium carbonate obtained under most conditions The proportion of arsonite phase is >80%; while the content disclosed in Chinese patent application CN102834356 shows that other compounds of strontium, such as strontium chloride or strontium acetate, etc. are used as additives to prepare precipitated calcium carbonate with a relatively low arsonite phase content (<70%) , so it is not suitable as an additive for the preparation of precipitated calcium carbonate with high aragonite phase content

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Step (1): Seed Synthesis

[0044] A 2L glass jacketed reactor with a stirring device is used to synthesize precipitated calcium carbonate, and the jacket is connected with an external constant temperature tank to circulate water to control the temperature of the suspension. The concentration of calcium hydroxide suspension is 2mol / l, and the volume is 1.6L. Additive 1 is ammonia water, NH 3 .H 2 The molar ratio of the amount of O added to the amount of calcium hydroxide is 1:10, the additive 2 is strontium oxide, and the molar ratio of the added amount to the amount of calcium hydroxide is 1:400, and the two additives are added to the calcium hydroxide suspension before carbonization and stirred at 45°C for 1 h to ensure uniform mixing. A mixture of carbon dioxide and nitrogen is introduced during carbonization, and the flow of the two is controlled by a flow meter to control the total flow and the proportion of carbon dioxide gas. In this embodiment, the total gas ...

Embodiment 2

[0048] Step (1): Seed Synthesis

[0049] A 2L glass jacketed reactor with a stirring device is used to synthesize precipitated calcium carbonate, and the jacket is connected with an external constant temperature tank to circulate water to control the temperature of the suspension. The calcium hydroxide suspension has a concentration of 1.6mol / l and a volume of 1.6L. Additive 1 is KOH, the molar ratio of additive amount to calcium hydroxide amount is 1:15, additive 2 is strontium hydroxide, and the molar ratio of additive amount to calcium hydroxide amount is 1:250, the two additives are mixed before carbonization Add calcium hydroxide suspension together and stir at 50°C for 1h to ensure uniform mixing. A mixture of carbon dioxide and nitrogen is introduced during carbonization, and the flow of the two is controlled by a flow meter to control the total flow and the proportion of carbon dioxide gas. In this embodiment, the total gas flow rate is 20L / (h·molCa(OH) after convers...

Embodiment 3

[0053] Step (1): Seed Synthesis

[0054] A 2L glass jacketed reactor with a stirring device is used to synthesize precipitated calcium carbonate, and the jacket is connected with an external constant temperature tank to circulate water to control the temperature of the suspension. The calcium hydroxide suspension has a concentration of 0.8mol / l and a volume of 1.6L. Additive 1 is Ba(OH) 2 , the molar ratio of the added amount to the amount of calcium hydroxide is 1:60, the additive 2 is strontium oxide, the molar ratio of the added amount to the amount of calcium hydroxide is 1:300, and the two additives are added to the calcium hydroxide suspension before carbonization and stirred at 60°C for 1 h to ensure uniform mixing. A mixture of carbon dioxide and nitrogen is introduced during carbonization, and the flow of the two is controlled by a flow meter to control the total flow and the proportion of carbon dioxide gas. In this embodiment, the total gas flow rate is 10L / (h·mo...

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Abstract

The present invention provides a precipitated calcium carbonate seed crystal containing aragonite crystal phase and a preparation method thereof. The precipitated calcium carbonate crystal seed containing aragonite crystal phase is characterized in that the weight content of the aragonite phase is >80%, and the seed crystal grain Diameter 0.1μm≤D50≤0.2μm. The precipitated calcium carbonate seed crystal containing aragonite crystal phase can be used to prepare metastable crystal phase precipitated calcium carbonate, and can also be directly applied to corresponding industrial fields. The invention has low cost and obvious technological advantages, and overcomes the technical prejudice that strontium salts such as strontium chloride cannot be prepared into precipitated calcium carbonate with high aragonite phase content in the prior art. Because of the above advantages, the technology provided by the present invention has broad application prospects.

Description

technical field [0001] The invention relates to a precipitated calcium carbonate crystal seed containing aragonite crystal phase and a preparation method thereof. Background technique [0002] Calcium carbonate is the most widely used white filler in the world, widely used in rubber, plastics, coatings, papermaking and other fields. Calcium carbonate has three crystal phases of calcite, aragonite and vaterite, among which the calcite phase is a thermodynamically stable crystal phase, and the aragonite and vaterite crystal phases are metastable crystal phases, which are easily converted into calcite crystal phases under certain conditions. Aragonite calcium carbonate is generally needle-shaped or rod-shaped, with an average refractive index of 1.63, which is higher than the average refractive index of calcite calcium carbonate (1.58). Due to its high refractive index and special shape, aragonite phase calcium carbonate is beneficial to increase the gloss of calendered coated...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F11/18
Inventor 孔凡滔吴秋芳马新胜李临江
Owner 建德华明科技有限公司
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