A kind of preparation method of layered structure microsphere precipitated calcium carbonate

Abstract

The invention discloses a preparation method of micro-spherical precipitated calcium carbonate with a layered structure. The preparation method comprises following steps: calcining limestone to prepare quicklime; performing digestion reactions between limestone and water to obtain lime milk; sieving lime milk by a 100-mesh sieve to remove the slag (refining), adjusting the concentration of lime milk to 10-100 g / L to obtain slurry of lime milk; heating slurry of lime milk to a temperature of 40-90 DEG C, delivering the slurry to a carbonization tower by a pump, adding an additive (soluble ion compounds) into the lime milk, evenly stirring, then introducing CO2 containing mixed gas into the lime milk, wherein during the reaction process, the lime milk is stirred at a low speed or is not stirred; stopping reactions when the pH value of the slurry reaches 7.5 to obtain calcium carbonate slurry; washing the calcium carbonate slurry by anhydrous ethanol, carrying out suction filtration, drying at a temperature of 60-70 DEG C, and grinding. The prepared precipitated calcium carbonate has the advantages of uniform morphology, good dispersibility, narrow particle size distribution, simple preparation technology, and good application prospect.

Description

technical field [0001] The invention belongs to the technical field of calcium carbonate preparation, in particular to a preparation method of layered structure microsphere precipitated calcium carbonate. Background technique [0002] Calcium carbonate is one of the most important inorganic chemical products, widely used in rubber, plastic, paper, coating, ink, medicine, food and other industries. Calcium carbonate is added as a filler to rubber, plastic, paper and other products, which not only plays the role of filling, increasing and reducing costs, but also improves the processing performance, mechanical strength and thermodynamic properties of the products. At the same time, due to the low price of raw limestone, simple production process, low energy consumption and relatively stable performance, calcium carbonate has become a hot research topic at home and abroad. Calcium carbonate with different crystal shapes plays an irreplaceable role in specific fields. People us...

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Problems solved by technology

The method has low cost, less consumption, simple by-products and treatment, controllable morphology, and high yield, but the formed calcium carbonate microspheres have agglomeration and poor dispersion

[0004] Chinese patent CN105692675B discloses a simple and convenient method for preparing calcium carbonate hollow microspheres. The invention uses sodium bicarbonate and calcium chloride as raw materials, mixes the two and shakes them quickly to make them gel, and centrifuges the precipitate to obtain calcium carbonate hollow microspheres. Microspheres, the process is simple, the cost is low, the raw materials are safe and non-toxic, and the specific surface area of ​​the microspheres is large, but the size of the microspheres is not uniform, the dispersion is poor, and the practical value is not large

However, the crystal is composed of vaterite and calcite, and the crystal structure is not uniform, which will cause unstable effects on practical applications.

[0010] According to the above, the method for preparing spherical calcium carbonate has inhomogeneous appearance and poor dispersibility, which causes the mechanical properties and processability of calcium carbonate to decline in rubber, plastics, and paper products, and affects the role of calcium carbonate in high value-added products. application

At the same time, the current method for preparing layered structure microsphere precipitated calcium carbonate lacks the ability of continuous mass production, and it is difficult to promote in industry

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