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Method for preparing superfine calcium carbonate compound particles

A technology of ultra-fine calcium carbonate and composite particles, which is applied in chemical instruments and methods, inorganic pigment treatment, fibrous fillers, etc., can solve the problems of affecting the coating effect and falling off, and achieve low cost, prevent agglomeration, and compact structure Effect

Active Publication Date: 2011-04-20
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

As the disclosed methods of Chinese Patent Publication No. CN101353486 and CN101225245, in order to obtain a uniform and compact silicon dioxide film layer on the surface of calcium carbonate particles, it is necessary to carry out high-speed shearing or strong mechanical dispersion to the system to make the calcium carbonate particles as single as possible. At the same time, the system must have a good stirring and mixing state, which is beneficial to prevent the dissolution of calcium carbonate and the self-aggregation of silica due to the uneven concentration of the system after adding acid; but the excessive shear dispersion on the particle surface is easy to make The thin layer of silica deposited on the surface falls off, affecting the coating effect

Method used

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  • Method for preparing superfine calcium carbonate compound particles
  • Method for preparing superfine calcium carbonate compound particles
  • Method for preparing superfine calcium carbonate compound particles

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Add 5 liters of refined lime milk suspensions with a concentration of 10% (weight concentration) and an initial temperature of 30°C in a 7-liter stirred reactor, add 20 g of sucrose and 13.75 g of triethanolamine at the same time, and feed the carbon dioxide content after stirring evenly. The kiln gas with 30% (volume concentration) starts carbonization reaction, and the kiln gas flow rate is 150 L / h. When the pH value of the carbonization reaction system was at 8.5, the aqueous solution of water glass with a modulus of 3.1 was added to the system. The total amount of water glass added was 142.63g, and the pH value of the control system was 9.5. After the water glass was added completely , stop feeding carbon dioxide gas, and let the reaction system age at 60°C for 2 hours, and then feed carbon dioxide gas. When the pH value of the system is 6.5, the reaction is completed, and the obtained slurry is filtered, washed, and dried to obtain cubic and similar Spherical ultra...

Embodiment 2

[0036]Adding 5 liters of concentration is 15% (weight concentration) initial temperature in the stirred reactor of 7 liters and is the refining lime milk suspension of 25 ℃, adds 6g sodium citrate simultaneously, after stirring, pass into carbon dioxide content and be 40 % (volume concentration) gas starts to undergo carbonization reaction, and the gas flow rate is 80L / h. When the pH value of the carbonization reaction system was at 7.0, adding 120.2g modulus to the system was the solution of water glass of 3.1, and the pH value of the control system was 9.0, after the water glass was added completely, stop feeding carbon dioxide gas, and Let the reaction system age at 50°C for 2.5 hours, and then pass in carbon dioxide gas. After the pH of the system is 6.5, the reaction is completed, and the obtained slurry is filtered, washed, and dried to obtain ultrafine calcium carbonate composite particles coated with silicon dioxide. .

[0037] The average particle size measured by el...

Embodiment 3

[0039] Adding 5 liters of concentrations in the stirred reactor of 7 liters is that the initial temperature of 13% (weight concentration) is the refining lime milk suspension and 8g sodium citrate at 30°C, and after stirring, it is 25% (volume) to feed carbon dioxide content Concentration) kiln gas starts carbonization reaction, and the flow rate of kiln gas is 100L / h. When the pH value of the carbonization reaction system was at 8.0, 317.9 g of 30 wt % potassium metasilicate aqueous solution was added to the system, and the pH value of the control system was 7.5. After the potassium silicate aqueous solution was added completely, stop feeding carbon dioxide gas, And let the reaction system age at 80°C for 3 hours, and then pass in carbon dioxide gas. After the pH value of the system is 6.5, the reaction is completed, and the obtained slurry is filtered, washed, and dried to obtain a silica-coated ultrafine calcium carbonate compound particles.

[0040] The average particle s...

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Abstract

The invention discloses a method for preparing superfine calcium carbonate compound particles, which comprises the following steps of: (1) introducing carbon dioxide gas or carbon dioxide-containing gas in suspension of calcium hydroxide, and reacting to obtain slurry containing superfine calcium carbonate particles; (2) when the pH value is reduced to be between 7.1 and 10.5, adding soluble aqueous solution of silicate, so that the pH value in a reaction system is between 7.5 to 9.5, after adding the silicate, stopping introducing the carbon dioxide-containing gas, aging at the temperature of between 40 and 90 DEG C for 0.5 to 3 hours, and introducing the carbon dioxide-containing gas until the pH value is between 6.5 to 7.0; and (3) filtering the obtained serous fluid, and washing by water to obtain the products. By the method, silicon dioxide can be subjected to film-forming cladding on the surface of calcium carbonate uniformly; and the method is simple in operating conditions, and the prepared calcium carbonate compound particles have the advantages of compact structures, high acid-resisting capacity, high dispersibility and low cost.

Description

technical field [0001] The invention relates to a preparation method of ultrafine calcium carbonate composite particles, in particular to a preparation method of silicon dioxide-coated ultrafine calcium carbonate composite particles with a core-shell structure. Background technique [0002] As an important functional inorganic filler, ultrafine calcium carbonate is widely used in papermaking, coatings, rubber, plastics and other fields, mainly to reduce costs and improve the overall performance of products. [0003] Calcium carbonate has a hydrophilic and oleophobic surface, so when it is used in a polymer or solvent system, it must be activated and modified to facilitate the dispersion of calcium carbonate in the matrix. At present, the activated modifiers widely used in industry are fatty acids and their salts. Calcium carbonate modified by such modifiers has a better effect in the use of PVC plastics with strong polarity, but it is not suitable for low-polarity PVC plasti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09C1/02C09C3/06
Inventor 陈雪梅马翠翠陈刚吴秋芳李鹏马新胜
Owner 建德华明科技有限公司
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