Mixed calcium carbonate, preparation method and application thereof

Abstract

The invention discloses mixed calcium carbonate, a preparation method and application thereof. The preparation method comprises the following steps of: (1) performing ultrafine grinding on heavy calcium carbonate water slurry with solid content (weight) of between 20 and 30 percent to obtain water slurry of which the weight content of the heavy calcium carbonate with grain diameter less than 2 mu m is between 60 and 90 percent; (2) adding a cationic polyelectrolyte solution which is equivalent to 0.2 to 2.0 percent of the weight of heavy calcium carbonate dry powder into the water slurry, and stirring the mixture for 0.5 to 1.0 hour; (3) then adding light calcium carbonate which is equivalent to 60 to 120 percent of the weight of the heavy calcium carbonate dry powder into the slurry, and then stirring the mixture for 20 to 30 minutes to obtain mixed calcium carbonate slurry; and (4) then collecting the mixed calcium carbonate from the mixed calcium carbonate slurry, wherein the mixed calcium carbonate slurry or calcium carbonate can be used as a paper-making filler. The mixed calcium carbonate synchronously has the respective advantages of the heavy calcium carbonate and the light calcium carbonate.

Description

Technical field [0001] The invention relates to calcium carbonate and its preparation method and application. Background technique [0002] The industrial products of calcium carbonate are powder materials made by mechanical or chemical processing of natural limestone ore. It is one of the most widely used inorganic fillers and pigments. Calcium carbonate is the most widely used internationally in the paper industry. It is mainly used as a filler for paper and as a coating material for high-quality paper such as white paper and coated paper. It can significantly improve the optical properties of paper and reduce costs. Titanium dioxide has high refractive index and scattering coefficient, which is a good papermaking filler. However, due to its high price, it is generally only used for high-grade tissue printing paper to increase the opacity of the paper; while calcium carbonate is low in price, and It can also improve the opacity of the paper and increase the ink absorption perfo...

AI Technical Summary

Problems solved by technology

However, a defect in the technology provided by the above-mentioned patents is that the complexability of light calcium and heavy calcium is poor, and the combination of the two is not tight.

[0006] The method that Chinese patent CN101209569 provides has had larger improvement than the method in the past, but the ammonium salt activator ionic strength that it uses is not high enough, and heavy calcium carbonate and light calcium carbonate are combined not firm enough; In addition, this method needs It is troublesome to add calcium hydroxide slurry to the activated heavy calcium slurry, and then pass carbon dioxide gas for carbonization;