Preparation technology for superfine surface-modified nano calcium carbonate

Abstract

The invention discloses a preparation technology for superfine surface-modified nano calcium carbonate. The preparation technology comprises the following steps: (1) carbonizing calcium hydroxide suspension, and adding a sodium sulfate and sodium citrate mixed crystalline form modifier until a pH value of slurry is equal to 7.0 to obtain nano calcium carbonate slurry; (2) adding a dispersing agentto the nano calcium carbonate slurry, stirring and controlling a temperature, and heat-preserving; (3) adding a surface modifier to the nano calcium carbonate slurry in step (2), controlling the temperature and ultrasonic-oscillating; (4) filter-pressing, centrifugal-dewatering, drying, depolymerizing and sieving the nano calcium carbonate slurry after surface treatment to obtain a finished product of the superfine surface-modified nano calcium carbonate. The preparation technology is capable of preventing agglomeration of the nano calcium carbonate, reinforcing hydrophobicity and compatibility on the surface of the nano calcium carbonate, and enabling the nano calcium carbonate to be easily dispersed in a polymer. In a preparation process, hard sodium hyalurongot soup liquid is used as an emulgator and used as a saponifier, a reaction saponification rate is high, and a raw material utilization rate is high.

Description

technical field [0001] The invention relates to the technical field of calcium carbonate preparation, in particular to a preparation process of ultrafine surface modified nano-calcium carbonate. Background technique [0002] Calcium carbonate is a widely used inorganic salt industrial product, which can be used as filling and modifying materials. It is commonly used in industries such as plastics, rubber, paint, adhesives, papermaking, food processing, and pharmaceuticals. daily life are closely related. [0003] Nano-calcium carbonate refers to calcium carbonate whose size is on the order of nanometers. From the crystal form, it can be divided into spindle, needle, spherical, cubic, chain, etc. It is a new type of ultrafine solid developed in the 1980s. Inorganic chemical materials. Due to the ultra-fine size of nano-calcium carbonate particles, its crystal structure and surface electronic structure have changed, resulting in small size effects, surface and interface effe...

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Problems solved by technology

[0004] When nano-calcium carbonate is directly applied to industrial products, due to its hydrophilic and oleophobic surface and strong polarity, it is difficult to disperse evenly in organic media, and the binding force with the base material is poor, which is easy to cause interface defects and lead to material performance degradation; in addition , the smaller the particle size of nano-calcium carbonate particles, the more atoms on the surface, the higher the surface energy, the stronger the adsorption, and it is in a thermodynamically unstable state. The particles are easy to agglomerate each other and cannot be well formed in the polymer matrix. Dispersion, which affects the practical application effect of nanoparticles

[0005] At present, industrial modification methods include dry modification and wet modification, among which fatty acid (salt) is mainly used as surface modifier in wet modification, but fatty acid (salt) has a strong hydrophobic effect and requires a higher Mechanical force and higher temperature can obtain better dispersion effect, but such surface treatment process will cause high cost, and the local agglomeration of nano-calcium carbonate is difficult to solve, and hard agglomeration between particles is inevitable

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