Process for producing chain structured corpuscular calcium carbonate

• US 4,157,379 A
• Filed: 11/30/1977
• Issued: 06/05/1979
• Est. Priority Date: 04/16/1976
• Status: Expired due to Term

• Current Assignee: Toyo Soda Manufacturing Co., Ltd.
• Original Assignee: Toyo Soda Manufacturing Co., Ltd.
• Inventors: Takitani, Masaru, Yamamoto, Kazuaki, Mitarai, Keiji, Arika, Junji
• Primary Examiner(s): Peters, G. O.
• Application Number:
  US05/856,114
• Time in Patent Office: 552 Days
• Field of Search: 423/430, 423/432
• US Class Current: 423/430
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01F 11/182 Preparation of calcium carbonate by carbonation of aqueous solutions and characterised by an additive other than CaCO3-seeds
• CPC Class Codes: C01F 11/183 the additive being an organic compound
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C08K 3/26 Carbonates; Bicarbonates

Abstract

Chain structured corpuscular calcium carbonate is produced by a carbonation of calcium hydroxide suspended in water in the presence of a chelating agent and a water soluble metal salt.

Claims

1. In a process for producing chain structured corpuscular calcium carbonate, an improvement which comprises a first carbonation of calcium hydroxide in a form of an aqueous suspension containing 0.1 to 20 wt. parts of a chelating agent for CaOH per 100 wt. parts of calcium hydroxide to form a viscous colloidal suspension and a second carbonation of the resulting viscous colloidal suspension containing 0.0001 to 0.5 mole of a water soluble metal salt which forms a water insoluble precipitate in an aqueous suspension of calcium hydroxide per 1 mole of calcium hydroxide as the starting material, carrying out the carbonation to be pH of 7 to 8 at the temperature of the aqueous suspension of 0°

to 30°

C. during the first and second carbonations, whereby chain-structured corpuscular calcium carbonate having an aspect ratio of length to diameter of from 5 to 50 and a primary particle average diameter of 0.01 to 0.1μ

is produced.

2. The process of claim 1 wherein the chelating agent is an organic compound which coordinates to a metal ion to form a metal chelate compound having multidentate ligand.

3. The process of claim 2 wherein the chelating agent is selected from the group consisting of aliphatic carboxylic acids;

aliphatic oxy- or keto-carboxylic acids;

aliphatic thiocarboxylic acids;

aromatic carboxylic acids;

aminopolycarboxylic acids, amino acids;

oximes;

oxines; and

alkali metal salts thereof.

4. The process of claim 1 wherein the water soluble metal salt which form water insoluble precipitates in an aqueous suspension of calcium hydroxide is an alkali metal phosphate.

5. The process of claim 1, wherein the water soluble salt which forms a water insoluble precipitate in an aqueous suspension of calcium hydroxide is an alkali metal sulfate.

6. The process of claim 1, wherein the water soluble salt which forms a water insoluble precipitate in an aqueous suspension of calcium hydroxide is aluminum trichloride.

7. The process of claim 1, wherein the water soluble salt which forms a water insoluble precipitate in an aqueous suspension of calcium hydroxide is iron sulfate or iron trichloride.

8. The process of claim 1, wherein the water soluble salt which forms a water insoluble precipitate in an aqueous suspension of calcium hydroxide is magnesium or barium chloride.