# US 11,111,388 B2 · Precipitated calcium carbonate with improved resistance to structural breakdown > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,388 B2 - Document ID: US11111388B2 - Status: Granted - Kind: B2 - Application number: 16/862,801 - Filed: 2020-04-30 - Published: 2020-08-27 - Granted: 2021-09-07 - Earliest claimed: 2015-07-31 - Assignees: Omya International AG - Applicants: Omya International AG - Inventors: Holger Spiegel; Wolfgang Kreuger; Mathieu Skrzypczak; Joe Wenk; Michael Dalton; Aaro Salonen; Marc Maurer; Patrick A. C. Gane; Catherine Jean Ridgway - Web page: https://patentgrep.com/patent/US11111388B2 ## CPC - C09C 1/021: {Calcium carbonates} - B01F 23/231264: {being in the form of plates, flat beams, flat membranes or films} - B01J 10/00: Chemical processes in general for reacting liquid with gaseous media other than in the presence of solid particles, or apparatus specially adapted therefor (B01J19/08 takes precedence; separation, e.g. distillation, also combined with chemical reactions B01D, {e.g. B01D3/009}) - C01F 11/181: {Preparation of calcium carbonate by carbonation of aqueous solutions and characterised by control of the carbonation conditions} - C01F 11/182: {Preparation of calcium carbonate by carbonation of aqueous solutions and characterised by an additive other than CaCO3-seeds} - C01F 11/183: {the additive being an organic compound} - C01P 2004/51: Particles with a specific particle size distribution - C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer - C01P 2006/12: Surface area - C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS} - B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C01F: COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides or polysulfides of magnesium, calcium, strontium, or barium C01B17/42; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia or cyanogen containing nitrogen and non-metals and optionally metals C01B21/082; amides or imides of silicon C01B21/087}; metal {imides or} amides C01B21/092, {C01B21/0923}; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20; {double sulfates of magnesium with sodium or potassium C01D5/12; with other alkali metals C01D15/00, C01D17/00}) - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract The present invention is directed to a process for producing precipitated calcium carbonate with improved resistance to structural breakdown, wherein the milk of lime is carbonated in the presence of at least one gas other than carbon dioxide, or the carbonation is carried out in the presence of a static gas bubble comminution unit as well as to precipitated calcium carbonate obtained by such a process. ## Claims ### Claim 1 A process for producing precipitated calcium carbonate comprising the steps of: a) providing a calcium oxide containing material, b) providing an aqueous solution, c) providing a gas comprising carbon dioxide, d) preparing a milk of lime comprising Ca(OH)2 by mixing the aqueous solution of step b) with the calcium oxide containing material of step a), e) carbonating the milk of lime obtained from step d) with the gas of step c) to form an aqueous suspension of precipitated calcium carbonate, wherein: the carbonation is carried out in the presence of a static gas bubble comminution unit that is located in the milk of lime and the gas of step c) is flushed around and/or through the static gas bubble comminution unit. ### Claim 2 (depends on 1) The process of claim 1, wherein the gas of step c) further comprises at least one gas other than carbon dioxide and the gas of step c) is introduced at a rate of 0.06 to 5.00 kg gas/h per kg of dry Ca(OH)2 with the proviso that the carbon dioxide is introduced at a rate of 0.05 to 3.50 kg CO2/h per kg of dry Ca(OH)2. ### Claim 3 (depends on 1) The process of claim 1, wherein the aqueous solution of step b) consists of water. ### Claim 4 (depends on 1) The process of claim 1, wherein the aqueous solution of step b) comprises one or more further additives selected from the group consisting of water soluble polymers, calcium carbonate nanoparticles, water-soluble calcium salts, and slaking additives. ### Claim 5 (depends on 1) The process of claim 1, wherein the calcium oxide containing material of step a) and the aqueous solution of step b) are mixed in a mass ratio from 1:1 to 1:15. ### Claim 6 (depends on 1) The process of claim 1, wherein the calcium oxide containing material of step a) and the aqueous solution of step b) are mixed in a mass ratio from 1:4 to 1:12. ### Claim 7 (depends on 1) The process of claim 1, wherein the gas of step c) comprises between 4 and 99 vol.-% carbon dioxide, based on the total volume of the gas. ### Claim 8 (depends on 1) The process of claim 1, wherein the gas of step c) comprises between 6 and 40 vol.-% carbon dioxide, based on the total volume of the gas. ### Claim 9 (depends on 1) The process of claim 1, wherein the gas of step c) comprises between 8 and 25 vol.-% carbon dioxide, based on the total volume of the gas. ### Claim 10 (depends on 1) The process of claim 1, wherein the gas in step e) is introduced at a rate of 0.06 to 5.00 kg gas/h per kg of dry Ca(OH)2, and/or the carbon dioxide is introduced at a rate of 0.05 to 3.50 kg CO2/h per kg of dry Ca(OH)2. ### Claim 11 (depends on 1) The process of claim 1, wherein the gas in step e) is introduced at a rate of 0.09 to 4.00 kg gas/h per kg of dry Ca(OH)2, and/or the carbon dioxide is introduced at a rate of 0.07 to 2.00 kg CO2/h per kg of dry Ca(OH)2. ### Claim 12 (depends on 1) The process of claim 1, wherein the gas in step e) is introduced at a rate of 0.12 to 3.00 kg gas/h per kg of dry Ca(OH)2, and/or the carbon dioxide is introduced at a rate of 0.10 to 1.50 kg CO2/h per kg of dry Ca(OH)2. ### Claim 13 (depends on 1) The process of claim 1, wherein the precipitated calcium carbonate obtained in step e) has a specific surface area from 2.0 to 80.0 m2/g, measured using nitrogen and the BET method according to ISO 9277:1995. ### Claim 14 (depends on 1) The process of claim 1, wherein the precipitated calcium carbonate obtained in step e) has a specific surface area from 2.5 to 13.0 m2/g, measured using nitrogen and the BET method according to ISO 9277:1995. ### Claim 15 (depends on 1) The process of claim 1, wherein the precipitated calcium carbonate obtained in step e) is in a form of particles having a weight median particle size d50of between 1.0 and 9.0 μm. ### Claim 16 (depends on 1) The process of claim 1, wherein the precipitated calcium carbonate obtained in step e) is in a form of particles having a weight median particle size d50 of 1.2 and 3.7 μm; and wherein the carbonation is carried out in the absence of agitators and stirrers. ### Claim 17 (depends on 1) The process of claim 1, wherein the precipitated calcium carbonate obtained in step e) is in a form of particles having a calcitic crystal form. ### Claim 18 (depends on 1) The process of claim 1, wherein the milk of lime is stirred during step e). ### Claim 19 (depends on 1) The process of claim 1, further comprising the steps of: f) separating the precipitated calcium carbonate from the aqueous suspension obtained from step e), and optionally g) drying the separated precipitated calcium carbonate obtained from step f). ### Claim 20 (depends on 19) The process of claim 19, wherein step g) takes place. ### Claim 21 (depends on 20) The process of claim 20, which further comprises a step h) of contacting at least a part of the surface of the precipitated calcium carbonate obtained from step g) with a surface-treatment agent.