Method for the manufacturing of a suspension comprising a calcium carbonate-comprising material

Abstract

The present invention relates to a process for the manufacturing of a calcium carbonate-comprising material, to a calcium carbonate-comprising material obtained by the process as well as the use of the calcium carbonate-comprising material for paper filler and paper coating applications, in plastics applications, in paints, in adhesives, in sealings, in concrete, in agriculture applications, in food applications, in cosmetic applications or in pharmaceutical applications.

1 . A calcium carbonate-comprising material obtained by the process comprising the steps of:
 a) providing at least two aqueous suspensions comprising a calcium carbonate-comprising material, wherein:
 i) the first aqueous suspension has a solid content from 1.0 to 82.0 wt.-%, based on the total weight of the aqueous suspension, and a content of particles having a particle size <2 μm in the range from 1.0 to 30.0 wt.-%; and 
 ii) the second aqueous suspension has a solid content from 10.0 to 82.0 wt.-%, based on the total weight of the aqueous suspension, and a content of particles having a particle size <2 μm in the range from >30.0 to 100.0 wt.-%; 
   b) mixing the at least two aqueous suspensions provided in step a) to obtain an aqueous suspension mixture;   c) grinding the aqueous suspension mixture obtained in step b) to obtain a ground aqueous suspension mixture;   d) optionally concentrating the ground aqueous suspension mixture obtained in step c) to remove at least a portion of water by mechanical means to obtain a partially dewatered calcium-carbonate material;   e) optionally drying the ground aqueous suspension mixture obtained in step c) or the partially dewatered calcium-carbonate material obtained in step d), if performed, to obtain a dried calcium carbonate-containing material; and   f) optionally treating the dried calcium-calcium carbonate material of step e) with at least one saturated aliphatic linear or branched carboxylic acid and/or with at least one mono-substituted succinic anhydride and/or at least one mono-substituted succinic acid and/or salty reaction product(s) and/or with at least one phosphoric acid ester blend of one or more phosphoric acid mono-ester and/or reaction products thereof and one or more phosphoric acid di-ester and/or reaction products thereof to obtain a hydrophobized calcium carbonate-comprising material.   
     
     
         2 . The material according to  claim 1 , wherein at least one dispersing agent is added to at least one of the at least two aqueous suspensions provided in step a) and/or to the aqueous suspension mixture obtained in mixing step b). 
     
     
         3 . The material according to  claim 2 , wherein the at least one dispersing agent is selected from the group consisting of sodium, potassium, calcium, magnesium, lithium, strontium, primary amine, secondary amine, tertiary amine, and/or ammonium salts, whereby the amine salts are linear or cyclic, of at least partly neutralized homopolymers or copolymers of (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid and derivatives of these acids, esters or amides, methylmethacrylate, methylacrylate, acrylamide, sodium hydrogen phosphate, polyphosphates, alkalipolyphosphates, carboxymethylcellulose, steric dispersants, comb polymers, and any mixture thereof. 
     
     
         4 . The material according to  claim 2 , wherein the at least one dispersing agent is sodium polyacrylate having a molecular weight M w  of from 4,000 to 10,000 g/mol. 
     
     
         5 . The material according to  claim 2 , wherein the at least one dispersing agent is sodium polyacrylate having a molecular weight M w  of from 4,000 to 8,000 g/mol. 
     
     
         6 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a BET specific surface area of between 0.1 and 30.0 m 2 /g, as measured using nitrogen and the BET method according to ISO 9277. 
     
     
         7 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a BET specific surface area of between 1.0 and 20.0 m 2 /g, as measured using nitrogen and the BET method according to ISO 9277. 
     
     
         8 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a BET specific surface area of between 2.0 and 14.0 m 2 /g, as measured using nitrogen and the BET method according to ISO 9277. 
     
     
         9 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a BET specific surface area of between 8.0 and 10.0 m 2 /g, as measured using nitrogen and the BET method according to ISO 9277. 
     
     
         10 . The material according to  claim 1 , wherein the ground aqueous suspension mixture obtained in step c) has a Brookfield viscosity of between 50 and 5,000 mPa·s 
     
     
         11 . The material according to  claim 1 , wherein the ground aqueous suspension mixture obtained in step c) has a Brookfield viscosity of between 75 and 1,500 mPa·s. 
     
     
         12 . The material according to  claim 1 , wherein the ground aqueous suspension mixture obtained in step c) has a Brookfield viscosity of between 150 and 500 mPa·s. 
     
     
         13 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a top cut particle size d 98  of ≤50.0 μm, and/or weight median particle size d 50  between 0.1 and 10.0 μm. 
     
     
         14 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a top cut particle size d 98  of ≤20.0 μm, and/or weight median particle size d 50  between 0.5 and 5.0 μm. 
     
     
         15 . The material according to  claim 1 , wherein the calcium carbonate-comprising material in the ground aqueous suspension mixture obtained in step c) has a top cut particle size d 98  of ≤10.0 μm, and/or weight median particle size d 50  between 1.0 and 2.0 μm. 
     
     
         16 . The material according to  claim 1 , wherein the solid content of the ground aqueous suspension mixture obtained in step c) is from 20.0 to 80.0 wt.-%, based on the total weight of the aqueous suspension. 
     
     
         17 . The material according to  claim 1 , wherein the solid content of the ground aqueous suspension mixture obtained in step c) is from 50.0 to 62.0 wt.-%, based on the total weight of the aqueous suspension. 
     
     
         18 . The material according to  claim 1 , which is selected from group consisting of natural calcium carbonate, precipitated calcium carbonate, dolomite, and any mixture thereof. 
     
     
         19 . The material according to  claim 1 , which is natural calcium carbonate from marble, chalk and/or limestone. 
     
     
         20 . The material according to  claim 1 , wherein step d) is preformed. 
     
     
         21 . The material according to  claim 1 , wherein step e) is performed. 
     
     
         22 . The material according to  claim 1 , wherein step f) is performed. 
     
     
         23 . A product comprising the calcium carbonate-comprising material according to  claim 1 . 
     
     
         24 . The product according to  claim 23 , which is a paper filler, a paper coating, a plastic, paint, an adhesive, a sealant, concrete, an agricultural product, food, a cosmetic product, or a pharmaceutical product.