CN104292886A - Method for preparing titanium dioxide-coated ground calcium carbonate powdered inorganic filler - Google Patents

Abstract

A preparation method of titanium dioxide-coated heavy calcium carbonate powdery inorganic filler, the steps are as follows: 1. Gradually add 100 parts by mass of 1500 mesh calcium carbonate powder to 100 parts of water, and then add the total mass of calcium carbonate and water 1% acetylacetone, and stir evenly; preferably, titanium dioxide is added to the slurry. 2. Slowly add 17 parts by mass of butyl titanate dropwise in the grinder, hydrolyze to generate titanium dioxide particles, and coat the surface of heavy calcium carbonate particles; preferably, slowly drop dispersant and surface modification during grinding agent, the surface modifier is a water-based titanate coupling agent, and the amount of the surface modifier is 1% of the total mass of calcium carbonate and water. 3. Filter, dry, and then pulverize the calcium carbonate coated with titanium dioxide particles; the drying and pulverization of titanium dioxide-coated heavy calcium carbonate is completed in a large flash dryer at one time. The process of the invention is simple, the pollution to the environment is small, and the quality of the produced titanium dioxide-coated heavy calcium carbonate product is guaranteed.

Description

A kind of preparation method of titanium dioxide-coated ground calcium carbonate powdery inorganic filler

technical field

The invention relates to a preparation method of an inorganic filler, that is, a preparation method of a titanium dioxide-coated ground calcium carbonate powdery inorganic filler.

Background technique

Heavy calcium carbonate, referred to as heavy calcium, is ground from natural carbonate minerals such as calcite, marble, and limestone. It is a commonly used powdered inorganic filler, widely used in coatings, rubber, plastics, paper and other industries. It has the advantages of high chemical purity, good thermal stability, low oil absorption and low refractive index. However, heavy calcium carbonate has poor acid resistance, and its whiteness is not as good as that of titanium dioxide. Therefore, it cannot be widely used as a white filler in plastic steel, coatings and other fields. If you disperse heavy calcium carbonate into a paint with a pH value that is too low, the calcium carbonate will dissolve and the paint itself will easily foam. In order to improve the whiteness and acid resistance of heavy calcium carbonate, the present invention proposes a preparation method of titanium dioxide-coated heavy calcium carbonate powdery inorganic filler, so that the heavy calcium carbonate can meet wider demands.

Contents of the invention

The key technology for the preparation of titanium dioxide-coated heavy calcium carbonate powdery inorganic filler is to find a process scheme so that the hydrolyzed titanium dioxide can coat heavy calcium carbonate, and the present invention just proposes such a preparation method.

The preparation method of this titanium dioxide coated ground calcium carbonate powdery inorganic filler is characterized in that the steps are as follows:

1. Preparation of heavy calcium carbonate slurry:

Gradually add 100 parts by mass of 1500 mesh calcium carbonate powder to 100 parts of water, then add calcium carbonate and 1% acetylacetone of the total mass of water, namely AcAc, and keep the stirring speed at 1000 rpm until the stirring is uniform ;

Preferably, titanium dioxide is added to the slurry, the mass fraction is 3-5 powders, and the particle size of the titanium dioxide is 3000 mesh.

Second, the coating of heavy calcium carbonate:

The coating of heavy calcium carbonate is carried out in a grinder, and 17 parts by mass of butyl titanate are slowly added dropwise during the grinding. After the addition, continue to grind for 0.5 hours. In the grinder, butyl titanate is Under the action of acetylacetone, it is hydrolyzed to generate titanium dioxide particles, which are coated on the surface of heavy calcium carbonate particles.

Preferably, the dispersant is slowly added dropwise during grinding, and the amount of the dispersant is 1% of the total mass of calcium carbonate and water. In the dispersant, the polycarboxylate sodium salt type dispersant SN5040 accounts for 1/3 of the mass of the dispersant, and the polyacrylic acid Ammonium salt polymer dispersant SN5027 accounts for 2/3 of the mass of the dispersant.

Preferably, a surface modifier is slowly added dropwise during grinding, the surface modifier is a water-based titanate coupling agent, and the amount of the surface modifier is 1% of the total mass of calcium carbonate and water.

3. Drying and crushing of heavy calcium carbonate:

After grinding, the calcium carbonate coated with titanium dioxide particles is filtered, dried, and then pulverized; the drying and pulverization of titanium dioxide-coated heavy calcium carbonate is carried out in a large flash dryer, and the drying and pulverization is completed once.

The process of the invention is simple, the pollution to the environment is small, and the quality of the produced titanium dioxide-coated heavy calcium carbonate product is guaranteed.

Detailed ways

Below by four embodiments the present invention is described in detail as follows:

Example one,

Stir 500 kg of water in a mixing tank, gradually disperse 500 kg of heavy calcium carbonate in the water, and add 10 kg of acetylacetone. The stirring speed was maintained at 1000 rpm. After stirring evenly, it was put into a grinder, and 85 kg of tetrabutyl titanate was added dropwise. After the dropwise addition, the stirring was continued for 0.5 hours. Grind and filter. The filtered heavy calcium carbonate is dried and pulverized once in a large flash dryer.

Example two,

The preparation method of this titanium dioxide coated ground calcium carbonate powdery inorganic filler, the steps are as follows:

1. Preparation of heavy calcium carbonate slurry:

Gradually add 100 parts by mass of 1500 mesh calcium carbonate powder to 100 parts of water, then add calcium carbonate and 1% acetylacetone of the total mass of water, namely AcAc, and keep the stirring speed at 1000 rpm until the stirring is uniform ;

At the same time, titanium dioxide is added to the slurry, the mass fraction is 4 powders, and the particle size of the titanium dioxide is 3000 mesh.

Second, the coating of heavy calcium carbonate:

The coating of heavy calcium carbonate is carried out in a grinder, and the stirring speed is maintained at 1000 rpm, and 17 parts by mass of butyl titanate are slowly added dropwise. After the dropwise addition, continue to grind for 0.5 hours. In the process, under the action of acetylacetone, butyl titanate is hydrolyzed to generate titanium dioxide particles, which are coated on the surface of heavy calcium carbonate particles;

3. Drying and crushing of heavy calcium carbonate:

After grinding, the calcium carbonate coated with titanium dioxide particles is filtered, dried, and then pulverized; the drying and pulverization of titanium dioxide-coated heavy calcium carbonate is carried out in a large flash dryer, and the drying and pulverization is completed once.

Embodiment three

In step 2, during grinding, slowly add the dispersant dropwise, the amount of the dispersant is 1% of the total mass of calcium carbonate and water, among the dispersant, polycarboxylate sodium salt type dispersant SN5040 accounts for 1/3 of the mass of the dispersant The polymer dispersant SN5027 of ammonium polyacrylate accounts for 2/3 of the dispersant quality; the rest of the steps are the same as in Example 2.

Embodiment Four

In step 2, during grinding, slowly add a surface modifier, the surface modifier is a water-based titanate coupling agent, and the amount of the surface modifier is 1% of the total mass of calcium carbonate and water; the remaining steps and implementation Example three is the same.

Claims (4)

1. a preparation method of titanium dioxide coated ground calcium carbonate powdery inorganic filler, is characterized in that, step is as follows: 1. Preparation of heavy calcium carbonate slurry: Gradually add 100 parts by mass of 1500 mesh calcium carbonate powder to 100 parts of water, then add calcium carbonate and 1% acetylacetone of the total mass of water, namely AcAc, and keep the stirring speed at 1000 rpm until the stirring is uniform ; Second, the coating of heavy calcium carbonate: The coating of heavy calcium carbonate is carried out in a grinder, and 17 parts by mass of butyl titanate are slowly added dropwise during the grinding. After the addition, continue to grind for 0.5 hours. In the grinder, butyl titanate is Under the action of acetylacetone, it is hydrolyzed to generate titanium dioxide particles, which are coated on the surface of heavy calcium carbonate particles; 3. Drying and crushing of heavy calcium carbonate: After grinding, the calcium carbonate coated with titanium dioxide particles is filtered, dried, and then pulverized; the drying and pulverization of titanium dioxide-coated heavy calcium carbonate is carried out in a large flash dryer, and the drying and pulverization is completed once. 2. the preparation method of a kind of titanium dioxide coating ground calcium carbonate powdery inorganic filler according to claim 1 is characterized in that, in step 1, is added with titanium dioxide in the slurry, and its mass fraction is 3- 5 powder, the particle size of titanium dioxide is 3000 mesh. 3. the preparation method of a kind of titanium dioxide coating ground calcium carbonate powdery inorganic filler according to claim 2 is characterized in that, in step 2, slowly drips dispersant in grinding, the amount of dispersant is calcium carbonate And 1% of the total mass of water, in the dispersant, the polycarboxylate sodium salt dispersant SN5040 accounts for 1/3 of the dispersant mass, and the polymer dispersant SN5027 of polyacrylic acid ammonium salt accounts for 2/3 of the dispersant mass. 4. the preparation method of a kind of titanium dioxide coating ground calcium carbonate powdery inorganic filler according to claim 3 is characterized in that, in step 2, slowly drip surface modifier in grinding, surface modifier is Water-based titanate coupling agent, the amount of surface modifier is 1% of the total mass of calcium carbonate and water.