Method for preparing calcium carbonate whiskers

A technology of calcium carbonate whiskers and sodium carbonate, applied in chemical instruments and methods, single crystal growth, crystal growth, etc., can solve the problems of complex preparation conditions, rising preparation costs, high pressure and temperature requirements, etc., and achieve simple preparation methods , high aspect ratio, good smoothness

Inactive Publication Date: 2011-10-12
LANZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Chinese patent 200510115404.6, the invention uses the hydrothermal method to prepare calcium carbonate whiskers, and reacts the urea and calcium chloride aqueous solution with rare earths and water-soluble high molecular polymers to form an inorganic-high molecular polymer homogeneous system. The requirements for pressure and temperature are high, and the corresponding preparation cost will also increase, and the aspect ratio of the prepared calcium carbonate whiskers is not high
But utilize soluble carbonate sodium carbonate and calcium chloride to prepare the biggest weakness of calcium carbonate whisker exactly exactly the concentration of reactant can not be too high, and this invention does not solve this problem well, causes the calcium carbonate whisker major diameter of preparation Compared with the existing technology, there is no great improvement
[0005] Chinese patent 200410022834.9, the manufacturing method of this invention uses quicklime or slaked lime as raw material, uses magnesium salt as crystal form control agent to produce aragonite type calcium carbonate whiskers by carbon dioxide carbonation method, this method prepares crystal whiskers by carbon dioxide carbonation method Whiskers, the aspect ratio of calcium carbonate whiskers prepared in acidic environment is very limited, it is difficult to obtain a great breakthrough in the existing technology
[0006] That is to say, due to constraints such as high cost, complex preparation conditions, too high concentration of reactants, and acidic environment of the reaction, it is difficult to prepare ideal calcium carbonate whiskers with high aspect ratio, which cannot meet the stringent requirements of the industry. higher demand

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] This example provides a method for preparing calcium carbonate whiskers. The method includes the following steps:

[0025] 1) Configuration concentration is 0.12mol·L -1 1L of sodium carbonate solution, the configuration concentration is 0.22mol·L -1 1L of calcium chloride solution;

[0026] 2) Heat the sodium carbonate solution and keep it in the temperature range of 81~84℃, add an equal volume of calcium chloride solution to the sodium carbonate solution, stir to prepare mixed solution A, and control the stirring speed to 80r / min , React until the pH value of the mixed solution is lower than 8.2;

[0027] 3) Pour carbon dioxide gas into the mixed solution A, add sodium hydroxide particles, stir to prepare the mixed solution B, keep the temperature at 81~84℃, control the stirring speed to 120r / min, stir and make the pH of the mixed solution B Keep the value within 8.2~8.5, and control the reaction time to 20min;

[0028] 4) After aging for 2 to 3 hours, after solid-liquid sep...

Embodiment 2

[0033] This example provides a method for preparing calcium carbonate whiskers. The method includes the following steps:

[0034] 1) Configuration concentration is 0.18mol·L -1 1L of sodium carbonate solution, the configuration concentration is 0.25mol·L -1 1L of calcium chloride solution;

[0035] 2) Heat the sodium carbonate solution and keep it in the temperature range of 81~84℃, add an equal volume of calcium chloride solution to the sodium carbonate solution, stir to prepare mixed solution A, and control the stirring speed to 120r / min , React until the pH value of the mixed solution is lower than 8.2;

[0036] 3) Pour carbon dioxide gas into mixed solution A, add sodium hydroxide particles, stir to prepare mixed solution B, keep the temperature at 81~84℃, control the stirring speed to 180r / min, stir and make the pH of mixed solution B Keep the value within 8.2~8.5, and control the reaction time to 100min;

[0037] 4) After aging for 2 to 3 hours, after solid-liquid separation an...

Embodiment 3

[0042] The difference between this example and example 2 is that the concentration of the sodium carbonate solution in step 1) is 0.14 mol·L -1 , The concentration of calcium chloride solution is 0.23mo1·L -1 . This example reduces the concentration of sodium carbonate solution and calcium chloride solution, and standardizes the concentration ratio. The prepared calcium carbonate whiskers are 30-65μm in length, 0.5-2.5μm in diameter, and have an aspect ratio of 30-50. The general aspect ratio of the calcium carbonate whiskers prepared by the method is 10-30, that is, the calcium carbonate whiskers prepared in this example also have a great breakthrough in the aspect ratio, and the product quality is high.

[0043] The difference in the aspect ratio between the calcium carbonate whiskers prepared in this example and the carbonate whiskers prepared by other methods is shown in the following table:

[0044] Preparation

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Abstract

The invention relates to a method for preparing calcium carbonate whiskers. The method comprises the following steps: preparing a sodium carbonate solution and a calcium chloride solution at a certain concentration, wherein the concentration of the calcium chloride solution is slightly more than that of the sodium carbonate solution; heating the sodium carbonate solution and keeping the temperature between 81 DEG C and 84 DEG C, adding an isopyknic calcium chloride solution into the sodium carbonate solution, stirring the solutions to prepare a mixed solution A and reacting until the pH value of the mixed solution is lower than 8.2, wherein the stirring speed is controlled between 80r/min (revolutions per minute) and 120r/min; and pumping carbon dioxide to the mixed solution A, adding sodium hydroxide particles, stirring the mixture to prepare a mixed solution B, carrying out stirring and maintaining the pH value of the mixed solution B between 8.2 and 8.5, wherein the temperature is continuously maintained between 81 DEG C and 84 DEG C; the stirring speed is controlled between 120r/min and 180r/min; and the reaction time is controlled between 20min and 100min. The method is simple, dispenses with excessive complex operations, is low in cost and can be used for overcoming the problems that the reactant concentration is too high and the acid reaction environment restricts preparation of the calcium carbonate whiskers and the like; and the prepared calcium carbonate whiskers have high length-diameter ratio, good smoothness and high purity.

Description

Technical field [0001] The invention relates to a method for preparing calcium carbonate whiskers, in particular to a method for preparing calcium carbonate whiskers with a higher aspect ratio. Background technique [0002] Whiskers are short fibers grown from high-purity single crystals. Their mechanical strength is equal to the force between adjacent atoms. The highly oriented structure of the whiskers not only makes them have high strength, high modulus and high elongation, but also has electrical properties. , Optical, magnetic, dielectric, conductive, superconducting properties. Calcium carbonate whisker is another new type of inorganic filler after nanometer calcium carbonate. It is non-toxic and odorless. It is a white pine-like solid and appears as needle-like single crystal under the microscope. Calcium carbonate whisker is used as a new generation of filler material. The product has the characteristics of high comprehensive performance, mechanical strength, good compre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B7/14C30B29/62C30B29/10
Inventor 刘伟生张国林
Owner LANZHOU UNIVERSITY
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