Nm-class calcium carbonate carbonization process

A technology of nano-calcium carbonate and process method, which is applied in the field of nano-powder preparation, can solve the problems of large investment in equipment, no discovery of nano-calcium carbonate, poor control of inclusion particles, etc., and achieve the effect of shortening the reaction time

Active Publication Date: 2007-05-16
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method has high efficiency in producing nano-calcium carbonate, good economic benefits, and can realize automatic large-scale production. The particle size is easy to control, and high-quality and stable nano-calcium carbonate can be produced. The disadvantage is that the equipment investment is large, and it is easy to control if it is not good. Incompletely carbonized inclusion particles
Including: "Method for preparing nano calcium carbonate particle" (CN1631789-A), "Method for preparing nano precipitated calcium carbonate from industrial waste water by sodium bicarbonate process" (CN1699176-A), "Process for preparing high activitycateactive nano CN1491893-A), "Preparation method of n

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  • Nm-class calcium carbonate carbonization process
  • Nm-class calcium carbonate carbonization process

Examples

Experimental program
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Example Embodiment

[0042] Example 1:

[0043] The lime was digested with hot water at 85°C, aged for 8 hours, and the ratio of grey to water was 1:4. The concentration of carbon dioxide in the mixed gas is 30%; the density of calcium hydroxide suspension is 1.055g / cm 3 , the concentration is 9.6%, and the sedimentation volume is 3.35ml / g. The additive citric acid is chemically pure, and the weight percentage of citric acid added before carbonization is 0.42%. Using a new carbonization process with circulation and strong shear mixing, the reaction time of the entire carbonization process lasted 31 minutes, the initial temperature was 18 °C, and the reaction end point was 33.5 °C; when the pH value of the suspension dropped to 7, the reaction was stopped, and the slurry settled. The volume is 5.84ml / g, filtered and dried. The particle size of the nano-calcium carbonate product is between 60-85nm, the crystal morphology is a regular cubic structure, and the specific surface area of ​​the nano-cal...

Example Embodiment

[0044] Example 2:

[0045] The lime was digested with hot water at 85°C, aged for 15 hours, and the ratio of grey to water was 1:4. The carbon dioxide concentration in the mixed gas is 30%; the density of the calcium hydroxide suspension is 1.055g / cm3, the concentration is 9.6%, and the sedimentation volume is 3.35ml / g. The additive citric acid is chemically pure, and the weight percentage of citric acid added before carbonization is 1.68%. Adopting a new carbonization process with circulation and strong shear mixing, the reaction time of the entire carbonization process lasted 32 minutes, the initial temperature was 18 °C, and the reaction end temperature was 34 °C; when the pH value of the suspension dropped to 7, the reaction was stopped, and the slurry The sedimentation volume is 3.54ml / g, filtered and dried, the particle size of the nano calcium carbonate product is between (50-60)×330nm, the crystal morphology is a chain structure, and the specific surface area of ​​the...

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Abstract

The invention discloses a carbonizing technological method of nanometer calcium carbonate in the nanometer powder making technological domain, which comprises the following steps: allocating calcium hydroxide solution with density at 8-12%(m) and density at 1.04-1.07g/cm3; setting the starting temperature at 15-20Deg C; pouring into intermittent stirring reacting autoclave; stirring completely; circulating the slurry; introducing composite gas of carbon dioxide into circulating pipe and strong cutting blender to blend with circulating suspension liquid; entering into buffer tank or autoclave through circulating pipe; stopping reacting until the pH value of suspension liquid is 7-7.5; maintaining 30-70min for entire carbonizing course; setting the terminal temperature within 30-40Deg C.

Description

technical field [0001] The invention relates to a new carbonization process of nano-calcium carbonate, in particular to a new carbonization process for preparing nano-calcium carbonate by using lime and carbon dioxide as raw materials at normal temperature, and belongs to the technical field of nano-powder preparation. Background technique [0002] Nano-calcium carbonate is an important inorganic fine chemical product. Compared with heavy calcium carbonate and light calcium carbonate products, it has the characteristics of fine particle size, large specific surface area, and high surface activity. Toughening effect, thereby improving the appearance and performance of the product, can partially replace expensive raw materials such as white carbon black, reduce product cost, and improve product quality. Nano-calcium carbonate has a wide range of applicability and market demand, and has a wide range of uses in the fields of coatings, plastics, rubber, adhesives, papermaking, in...

Claims

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Application Information

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IPC IPC(8): C01F11/18
Inventor 盖国胜杨玉芬练恩生朱勇蔡振芳
Owner TSINGHUA UNIV
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