초록 ▼

The invention provides calcium carbonate particles comprising a core and projections formed thereon, and process for preparing same. The calcium carbonates of this invention are useful as fillers and pigments for rubbers, plastics, papers, etc. because of their peculiar configuration and unique prop

The invention provides calcium carbonate particles comprising a core and projections formed thereon, and process for preparing same. The calcium carbonates of this invention are useful as fillers and pigments for rubbers, plastics, papers, etc. because of their peculiar configuration and unique properties.

대표청구항 ▼

A process for preparing calcium carbonate particles, said particles comprising a core about 0.5 to about 6.5 m100 to about 4000 projections formed on the surface of the core and having a length (L) of about 0.25 to about 2.00 m0.08 to about 0.20 m3 to about 10, the calcium carbonate having a void vo

A process for preparing calcium carbonate particles, said particles comprising a core about 0.5 to about 6.5 m100 to about 4000 projections formed on the surface of the core and having a length (L) of about 0.25 to about 2.00 m0.08 to about 0.20 m3 to about 10, the calcium carbonate having a void volume of about 1.0 to about 1.8 ml/g, a specific surface area of about 5 to about 15 m2/g, an an oil absorption of about 45 to about 60 ml/100 g., said process comprising: (i) the first step of adding to a suspension of calcium hydroxide in a concentration of about 5 to about 15% by weight at least one of phosphoric acids and water-soluble salts thereof in an amount of about 0.01 to about 5.0 parts by weight, calculated as P2O5, per 100 parts by weight of the calcium hydroxide, and spraying the mixture into a reactor in droplets of about 0.2 to about 1.0 mm in diameter at a temperature of about 30°to about 80°C. in countercurrent relation to a carbon dioxide-containing gas passed upward through the reactor at a superficial velocity of about 0.02 to about 1.0 m/sec, (ii) the second step of spraying the mixture from the first step into another reactor in droplets of about 1.0 to about 2.0 mm in diameter at a temperature of about 30°to about 80°C. in countercurrent relation to a carbon dioxide-containing gas passed upward through the reactor at a superficial velocity of about 0.5 to about 2.5 m/sec, and (iii) the third step of spraying the mixture from the second step into another reactor in droplets of about 1.5 to about 2.0 mm in diameter at a temperature of about 30°to about 80°C. in countercurrent relation to a carbon dioxide-containing gas passed upward through the reactor at a superficial velocity of about 1.5 to about 3.0 m/sec.