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Method for preparing calcium carbonate powder

A technology of calcium carbonate powder and carbon dioxide, applied in the direction of calcium carbonate/strontium/barium, etc., can solve the problems of high impurity content in calcium carbonate products, large particle size of calcium carbonate particles, difficult to control crystal form, etc. The effect of uniform particle size and improved purity

Inactive Publication Date: 2009-12-02
GUANGDONG FENGHUA ADVANCED TECH HLDG
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

The disadvantages of this carbonization method are: most of the calcium hydroxide suspension obtained by digestion has low purity, and the generated calcium carbonate product has high impurity content; the solubility of calcium hydroxide is small, and the bubble size containing carbon dioxide is often large, due to the carbonization reaction It involves a gas-liquid-solid three-phase system. Calcium ions in the solution react with carbon dioxide on the surface of the bubbles to form calcium carbonate solids, so the carbonization rate is usually relatively slow, and the resulting calcium carbonate particles have large particle sizes and uneven distribution. also difficult to control
This method can generate calcium carbonate powders with different shapes according to the addition of different additives, but at the same time it also introduces a large amount of impurities, which is not suitable for the field of MLCC production

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  • Method for preparing calcium carbonate powder
  • Method for preparing calcium carbonate powder

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Effect test

Embodiment 1

[0013] A method for preparing calcium carbonate powder, the steps are: A. Add a calcium oxide impurity remover to the calcium chloride solution, the weight of which is 0.1-0.2% of the weight of calcium chloride; heat to 80±5°C while stirring, And keep this temperature for 20±5min, then let it stand to cool to within 50℃, and filter the solution into the reaction kettle; B. Add sodium hydroxide solution with a molar ratio of 1.3-1.5 to the solution obtained in step A, and the addition is complete Stirring after circulation; C. Pour carbon dioxide into the solution of step B under agitation to carry out the carbonization reaction. During the carbonization process, control the reaction temperature to 22±2°C until PH=7 to stop the reaction, and finally filter, wash, Calcium carbonate powder is obtained by drying. The adding speed of the sodium hydroxide solution in step B is 67ml±5 / min, and the circulation stirring time is 10±5min. In the step C, the total flow of carbon dioxide is co...

Embodiment 2

[0015] A method for preparing calcium carbonate powder, the steps are: A. Add calcium hydroxide impurity remover to the calcium chloride solution, the weight of which is 0.1-0.2% of the weight of calcium chloride; heating to 80±5°C while stirring , And keep this temperature for 20±5min, then let it stand to cool to within 50℃, filter the solution into the reaction kettle; B. Add sodium hydroxide solution with a molar ratio of 1.3-1.5 to the solution obtained in step A, add Cycling stirring after the completion; C. Pour carbon dioxide into the solution of step B under stirring to carry out the carbonization reaction. During the carbonization process, control the reaction temperature to 30±2°C until the PH=7 to stop the reaction, and finally filter and wash , Dry to obtain calcium carbonate powder. The adding speed of the sodium hydroxide solution in step B is 67ml±5 / min, and the circulation stirring time is 10±5min. In the step C, the total flow of carbon dioxide is controlled at 8...

Embodiment 3

[0017] A method for preparing calcium carbonate powder, the steps are: A. Add calcium oxide and calcium hydroxide impurity remover to the calcium chloride solution, the weight of which is 0.1-0.2% of the weight of calcium chloride; heating to 80% while stirring ±5℃, and keep this temperature for 20±5min, then let stand and cool to within 50℃, filter the solution into the reaction kettle; B. Add sodium hydroxide solution with a molar ratio of 1.3-1.5 to the solution obtained in step A After the addition is complete, circulate and stir; C. Pour carbon dioxide into the solution of step B under stirring to carry out the carbonization reaction. During the carbonization process, control the reaction temperature to 38±2°C until the PH=7 to stop the reaction. Filter, wash, and dry to obtain calcium carbonate powder. The adding speed of the sodium hydroxide solution in step B is 67ml±5 / min, and the circulation stirring time is 10±5min. In the step C, the total flow of carbon dioxide is con...

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Abstract

The invention discloses a method for preparing calcium carbonate powder, which comprises the following steps: A, adding an impurity removal agent into calcium chloride solution, heating the mixture until the mixture is boiled for 30+ / -5 minutes while stirring, then standing the mixture for 4+ / -1 hours, and filtering the solution into a reaction kettle when the temperature of the solution is reduced to the room temperature; B, adding sodium hydroxide solution of which the molar ratio is 1.0 to 1.2 into the solution obtained in the step A, and then stirring the mixture circularly; and C, in the stirring state, introducing carbon dioxide into the solution of the step B to perform carbonization reaction, controlling the reaction temperature between 20 and 35 DEG C in the process of the carbonization and stopping the reaction when the pH is equal to between 6 and 7, and finally filtering, washing and drying the prepared calcium carbonate powder. The prepared submicron high-performance superfine calcium carbonate powder has a specific area of 6 to 9 square metes per gram and narrow grain size distribution, and is quite suitable to be applied to high-end MLCC products.

Description

Technical field [0001] The invention relates to a preparation method of calcium carbonate powder, in particular to a preparation method of ultrafine calcium carbonate powder special for ceramic capacitor MLCC. Background technique [0002] As an important inorganic chemical product, calcium carbonate has the characteristics of simple production process and stable performance. It is widely used in plastics, rubber, papermaking, coatings, daily chemicals and other fields. Its special quantum size effect, small size effect, and surface effect make it obvious in terms of reinforcement, transparency, dispersion, leveling, and thixotropy compared with conventional powder materials. Advantage. With the development of modern industrial technology, all walks of life have higher and higher requirements for light calcium carbonate, and the demand is also increasing. For example, the production of MLCC industry often requires special ultra-fine calcium carbonate with low impurity content, hi...

Claims

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Application Information

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IPC IPC(8): C01F11/18
Inventor 聂晓明刘艳丽蒋训莎赵兴国林滟新黎杰光
Owner GUANGDONG FENGHUA ADVANCED TECH HLDG
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