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CN-120208273-B - Preparation method and application of rod-shaped nano calcium carbonate

CN120208273BCN 120208273 BCN120208273 BCN 120208273BCN-120208273-B

Abstract

The invention belongs to the field of calcium carbonate materials, and particularly relates to a preparation method and application of rod-shaped nano calcium carbonate. The preparation process is optimized, so that the preparation cost is greatly reduced, the obtained rod-shaped nano calcium carbonate is stable in structure, the length-diameter ratio is stable at 15-20:1, the dispersibility is good, the heat conductivity coefficient can be greatly reduced, and the rod-shaped nano calcium carbonate has remarkable economic and social benefits when being applied to heat-insulating waterproof materials.

Inventors

  • ZHANG HUA
  • WU CHUNHUA
  • ZHANG ZHIWEI
  • ZHANG ZHIHONG
  • LIU XIANGXIANG
  • LIU QIANG

Assignees

  • 江西势通钙业有限公司

Dates

Publication Date
20260508
Application Date
20250312

Claims (7)

  1. 1. The preparation method of the rod-shaped nano calcium carbonate is characterized by comprising the following steps of: S1, preprocessing, namely mixing the desulfurization gypsum of the power plant with deionized water according to the solid-liquid volume ratio of 1:3-5, ball-milling, adding a pH regulator to adjust the pH to 6.5-7.5, and centrifuging to obtain calcium slurry; S2, precursor treatment, namely mixing the calcium slurry obtained in the step S1 with deionized water according to the volume ratio of 1:6-8, adding a composite dispersing agent, and carrying out ultrasonic treatment for 15-20min to obtain precursor colloid, wherein the composite dispersing agent is a mixture of sodium citrate and sodium lignin sulfonate with the volume ratio of 1-2:1, and the use amount is 1-5% of the total mass of the precursor colloid; S3, carbonizing reaction, namely regulating the pH value of a precursor colloid to 9-11 by using a pH regulator, introducing CO 2 gas into the precursor colloid, heating to 40-60 ℃, starting ultrasonic waves, stirring for 20-30min, then continuously introducing CO 2 gas to pH value of 6-7, adding a crystallization regulator, and carrying out intermittent microwave heating treatment for 2-3h to form rod-shaped calcium carbonate slurry, wherein the crystallization regulator is polyvinylpyrrolidone, the use amount of the crystallization regulator is 0.1-0.3% of the total mass of the precursor colloid, the microwave frequency of the intermittent microwave heating treatment is 915MHz, and the intermittent microwave heating frequency is 2-5min; s4, separating and purifying, namely centrifuging the rod-shaped calcium carbonate slurry, adding sodium carboxymethylcellulose, uniformly mixing, washing with ethanol for 2-3 times, and vacuum drying at 50-60 ℃ for 5-8 hours to obtain rod-shaped calcium carbonate powder; S5, post-treatment, namely ball-milling and mixing the rod-shaped calcium carbonate powder obtained in the step S4 with a silane coupling agent, and drying at 70-80 ℃ for 2-3 hours to obtain a final product.
  2. 2. The method for preparing rod-like nano calcium carbonate according to claim 1, wherein in S1, after ball milling, the particle size of the power plant desulfurization gypsum is less than or equal to 40 μm.
  3. 3. The method for preparing rod-shaped nano calcium carbonate according to claim 1, wherein in S2, the power of the ultrasonic treatment is 300-350W.
  4. 4. The preparation method of the rod-shaped nano calcium carbonate according to claim 1, wherein in S3, the power of the ultrasonic wave is 150-200W, and the inflow rate of the CO 2 is 0.5-1.5L/min.
  5. 5. The preparation method of the rod-shaped nano calcium carbonate according to claim 1, wherein in S4, the centrifugal speed is 4000-5000rpm, the time is 10-20min, and the amount of added sodium carboxymethylcellulose is 0.5-1% of the mass of the rod-shaped calcium carbonate slurry.
  6. 6. The preparation method of the rod-shaped nano calcium carbonate according to claim 1, wherein in S5, the mass ratio of the rod-shaped calcium carbonate powder to the silane coupling agent is 1:0.1-0.3, and the silane coupling agent is KH-550.
  7. 7. The method for preparing the rod-shaped nano calcium carbonate according to claim 1, wherein the length-diameter ratio of the rod-shaped nano calcium carbonate product is 15-20:1.

Description

Preparation method and application of rod-shaped nano calcium carbonate Technical Field The invention belongs to the field of calcium carbonate materials, in particular relates to a preparation method and application of rod-shaped nano calcium carbonate, and more particularly relates to a preparation method and application of rod-shaped nano calcium carbonate capable of meeting the requirements of heat insulation materials. Background Calcium carbonate is an odorless white solid inorganic compound, and has been rapidly developed in recent years, and has various specifications and varieties, and is widely used in various fields such as rubber, plastics, paper making, ink, cosmetics, and the like. The calcium carbonate has various morphologies including cubes, spheres, needles, rods and the like, each morphology has unique characteristics, and the requirements of different industries on the morphology, the particle size, the surface properties and the like of the calcium carbonate are different. For example, rod-like nano calcium carbonate has a unique structure, so that the rod-like nano calcium carbonate has various excellent properties, such as reinforcing and toughening, large oil absorption, adsorption, desorption, grinding, fragrance retention, slow release and the like, and is attracting more and more attention in various fields. At present, the preparation process of the rod-shaped nano calcium carbonate is mature, wherein more calcium carbonate is used or is obtained by calcining limestone to prepare calcium hydroxide emulsion and then reacting the calcium hydroxide emulsion with carbon dioxide, the process needs high energy consumption for high-temperature calcination, the discharged carbon dioxide is not recycled, the greenhouse effect is easy to cause, the environment is not protected, meanwhile, the reaction condition is complex, the particle size distribution is wide, the dispersibility is poor if the control is not easy, and in addition, the hydrophobicity of the common rod-shaped calcium carbonate is poor, so that the performance requirement of some heat-insulating waterproof materials on the dispersed filler is difficult to meet. Disclosure of Invention Aiming at the defects or improvement demands of the prior art, the invention provides a preparation method and application of rod-shaped nano calcium carbonate, wherein the length-diameter ratio of the rod-shaped nano calcium carbonate obtained by the preparation method is 15-20:1, the dispersion is good, the rod-shaped nano calcium carbonate can be applied to heat-insulating waterproof materials, and the rod-shaped nano calcium carbonate has excellent low heat-conducting property and waterproof property. In order to achieve the above object, the present invention provides a method for preparing rod-shaped nano calcium carbonate, comprising the steps of: S1, preprocessing, namely mixing desulfurization gypsum of a power plant with deionized water according to the solid-liquid volume ratio kg/L of 1:3-5, ball-milling, adding a pH regulator to adjust the pH to 6.5-7.5, and centrifuging to obtain calcium slurry, wherein the filtrate is processed to reach the standard and then discharged; S2, precursor treatment, namely mixing the calcium slurry obtained in the step S1 with deionized water according to the volume ratio of 1:6-8, adding a composite dispersing agent, and carrying out ultrasonic treatment for 15-20min to obtain precursor colloid; S3, carbonizing reaction, namely introducing CO 2 gas into the precursor colloid by using a pH regulator until the pH value of the precursor colloid is 9-11, heating to 40-60 ℃, starting ultrasonic waves, stirring for 20-30min, then continuously introducing CO 2 gas until the pH value is 6-7, adding a crystallization regulator, and performing intermittent microwave heating treatment for 2-3h to form rod-shaped calcium carbonate slurry; s4, separating and purifying, namely centrifuging the rod-shaped calcium carbonate slurry, adding sodium carboxymethylcellulose, uniformly mixing, washing with ethanol for 2-3 times, and vacuum drying at 50-60 ℃ for 5-8 hours to obtain rod-shaped calcium carbonate powder; S5, post-treatment, namely ball-milling and mixing the rod-shaped calcium carbonate powder obtained in the step S4 with a silane coupling agent, and drying at 70-80 ℃ for 2-3 hours to obtain a final product. The method uses the desulfurization gypsum of the power plant as a calcium source, does not need calcination, reduces energy consumption, can realize recycling of solid waste, has no carbon dioxide emission, reduces production cost, is more environment-friendly, can prevent calcium slurry agglomeration by mixing the calcium source with a composite dispersing agent to prepare a precursor colloid, provides a stable system for subsequent carbonization reaction, promotes crystal nucleus uniform distribution by ultrasonic cavitation effect at a higher pH value by sectionally introducing CO 2 gas and adopting a