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 mum 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, andstirring 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, andthen 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 mixedcalcium 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 lightcalcium carbonate.

Description

technical field [0001] The present invention relates to a kind of calcium carbonate and its preparation method and application. Background technique [0002] The industrial product of calcium carbonate is a powder material produced by mechanically or chemically processing natural limestone ore. It is one of the most widely used inorganic fillers and pigments. Calcium carbonate is most widely used in the paper industry in the world. It is mainly used as a filler for paper and a coating material for high-quality paper such as whiteboard paper and coated paper, which can significantly improve the optical properties of paper and reduce costs. Titanium dioxide has a high refractive index and scattering coefficient, and is a good paper-making filler. However, due to its high price, it is generally only used in high-grade thin-page printing paper to improve the opacity of the paper; and calcium carbonate is due to its low price and It can also improve the opacity of paper, increa...

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 combine 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;