Method for sizing of mineral matter in the presence of additives containing glycerol, products obtained and their uses

Abstract

The present invention concerns a method for sizing of mineral matter using a sizing aid additive comprising glycerol and/or at least one polyglycerol allowing the efficiency of air sizing to be increased, or involving a specific sizing energy which is reduced relative to an additive-free air sizing, whilst obtaining a sized mineral matter compatible with an application in an aqueous medium. It also concerns the use of the product obtained in this manner, in paint, plastic, food applications destined for human or animal consumption, pharmaceutical formulation, paper pulp or paper coating.

1 . A product obtained by a method of sizing of mineral matter comprising the following steps:
 a) supplying at least one mineral matter comprising dolomite, or talc, or titanium dioxide, or alumina, or kaolin, or calcium carbonate, or any blend thereof;   b) supplying at least one sizing aid additive:
 (i) consisting of glycerol, in an aqueous or pure form; or 
 (ii) consisting of glycerol with one or more of the following agents: ethylene glycol, monopropylene glycol, triethylene glycol, an inorganic acid or an inorganic acid salt, formic or citric acid or a formic or citric acid salt, an organic polyacid or an organic polyacid salt, an alcanolamine, a poly(ethylene imine), a polyalkylene glycol polymer of molecular mass by weight of between 200 g/mole and 20,000 g/mole, a polyalkylene glycol polymer of molecular mass by weight of between 600 g/mole and 6,000 g/mole, a carbohydrate having a root mean square of the radius of gyration equal to or less than the modal radius of the mineral matter, one or more polyglycerols, wherein the agent or agents are in the aqueous or pure form, or 
 (iii) comprising one or more polyglycerols in the absence of glycerol; 
   c) bringing into contact, once or several times, the mineral matter from step a) with the sizing aid additive of step b) in one or more dry grinding and/or dry blending steps;   d) undertaking at least one sizing step of the mineral matter obtained in step c) in a gaseous environment, in order to obtain at least two fractions of particles of different average particle sizes; and   e) optionally repeating steps c) and/or d) on all or part of the sized mineral matter resulting from step d).   
     
     
         2 . The product according to  claim 1 , wherein the average particle sizes of the fractions of particles obtained in step d) differ by at least 0.1 μm relative to one another. 
     
     
         3 . The product according to  claim 1 , wherein when two fractions are obtained in step d) the average particle sizes of the fractions have a ratio of 1:1.05 to 1:150. 
     
     
         4 . The product according to  claim 1 , wherein when two fractions are obtained in step d) the average particle sizes of the fractions have a ratio of 1:1.1 to 1:1.15. 
     
     
         5 . The product according to  claim 1 , wherein the sizing additive consists of glycerol in pure form or an aqueous form of water and glycerol. 
     
     
         6 . The product according to  claim 5 , wherein the additive consists of water and glycerol containing 25% to 95% by weight of glycerol relative to total weight of water and glycerol. 
     
     
         7 . The product according to  claim 5 , wherein the additive consists of water and glycerol containing 45% to 90% by weight of glycerol relative to total weight of water and glycerol. 
     
     
         8 . The product according to  claim 5 , wherein the additive consists of water and glycerol containing 75% to 85% by weight of glycerol relative to total weight of water and glycerol. 
     
     
         9 . The product according to  claim 1 , wherein the additive consists of glycerol with one or more of the following agents: ethylene glycol, monopropylene glycol, triethylene glycol, an inorganic acid or an inorganic acid salt, formic or citric acid or a formic or citric acid salt, an organic polyacid or an organic polyacid salt, an alcanolamine, a poly(ethylene imine), a polyalkylene glycol polymer of molecular mass by weight of between 200 g/mole and 20,000 g/mole, a polyalkylene glycol polymer of molecular mass by weight of between 600 g/mole and 6,000 g/mole, a carbohydrate having a root mean square of the radius of gyration equal to or less than the modal radius of the mineral matter, one or more polyglycerols, wherein the agent or agents are in the aqueous or pure form. 
     
     
         10 . The product according to  claim 9 , wherein the agent is an inorganic acid that is a phosphoric acid. 
     
     
         11 . The product according to  claim 9 , wherein the agent is an inorganic salt that is a mono-, di- or tri-alkaline salt, or a salt of a cation of Group I or II of the Periodic Table of the Elements. 
     
     
         12 . The product according to  claim 9 , wherein the agent is a salt of formic or citric acid that is a mono-, di- or tri-alkaline salt, or a salt of a cation of Group I or II of the Periodic Table of the Elements. 
     
     
         13 . The product according to  claim 9 , wherein the agent is an organic polyacid having the formula COOH—(CH 2 ) n —COOH, wherein n is an integer having a value of between 0 and 7, inclusive, or a mono- or di-alkaline salt of an organic polyacid of formula COOH—(CH 2 )n-COOH, in which n is equal to an integer having a value of between 0 and 7 inclusive, or a polymeric organic polyacid of one or more of the following monomers, in the acid form, or in the form which is partially or fully neutralised with one or more cations of Group I or II of the Periodic Table of the Elements: acrylic, methacrylic, maleic or itaconic. 
     
     
         14 . The product according to  claim 9 , wherein the agent is an oxalic acid, a pimelic acid or an adipic acid. 
     
     
         15 . The product according to  claim 9 , wherein the agent is a alcanolamine chosen from among 2-amino-2-methyl-1-propanol, 2-amino-2-ethyl-1,3-propanediol, tri-ethanolamine, N-butyldiethanolamine and tri-iso-propanolamine, whether or not neutralized, or is chosen from among their forms which are neutralised by means of a formic or citric acid salt, or of an organic polyacid salt. 
     
     
         16 . The product according to  claim 9 , wherein the agent is a polyalkylene glycol polymer that is a polyethylene glycol, a polypropylene glycol, or an ethylene-propylene glycol copolymer, whether random or block. 
     
     
         17 . The product according to  claim 9 , wherein the agent is a carbohydrate having a root mean square of the radius of gyration of the carbohydrate equal to or less than the modal radius of the mineral matter, and wherein the carbohydrate is glucose, fructose, sucrose, starch or cellulose. 
     
     
         18 . The product according to  claim 9 , wherein the agent is a polyglycerol or polyglycerols chosen from among di-glycerol, tri-glycerol, tetra-glycerol, penta-glycerol, hexa-glycerol, hepta-glycerol, octa-glycerol, nona-glycerol and deca-glycerol, or any blend thereof. 
     
     
         19 . The product according to  claim 9 , wherein the additive contains 20% to 95% by weight of glycerol, 1% to 50% by weight of the agent and 0% to 65% by weight of water, relative to their total weight, wherein the sum of percentages by weight of glycerol, the agent and of water are equal to 100%. 
     
     
         20 . The product according to  claim 9 , wherein the additive contains 30% to 90% by weight of glycerol, 10% to 45% by weight of the agent and 0% to 60% by weight of water, relative to their total weight, wherein the sum of percentages by weight of glycerol, the agent and of water are equal to 100%. 
     
     
         21 . The product according to  claim 9 , wherein the additive contains 35% to 75% by weight of glycerol, 30% to 40% by weight of the agent and 5% to 50% by weight of water, relative to their total weight, wherein the sum of percentages by weight of glycerol, the agent and of water are equal to 100%. 
     
     
         22 . The product according to  claim 1 , wherein the additive comprises one or more polyglycerols in the absence of glycerol. 
     
     
         23 . The product according to  claim 22 , wherein the polyglycerol or polyglycerols are chosen from among di-glycerol, tri-glycerol, tetra-glycerol, penta-glycerol, hexa-glycerol, hepta-glycerol, octa-glycerol, nona-glycerol and deca-glycerol, or any blend thereof. 
     
     
         24 . The product according to  claim 22 , wherein the additive consists of one or more polyglycerols in pure form. 
     
     
         25 . The product according to  claim 22 , wherein the additive consists of water and one or more polyglycerols. 
     
     
         26 . The product according to  claim 25 , wherein the additive contains 25% to 95% by weight of polyglycerols relative to their total weight, the remainder consisting of water. 
     
     
         27 . The product according to  claim 25 , wherein the additive contains 45% to 90% by weight of polyglycerols relative to their total weight, the remainder consisting of water. 
     
     
         28 . The product according to  claim 25 , wherein the additive contains 75% to 85% by weight of polyglycerols relative to their total weight, the remainder consisting of water. 
     
     
         29 . The product according to  claim 1 , wherein the mineral matter is contacted with an additive that includes 100 to 5,000 ppm of glycerol or polyglycerol, relative to the dry weight of the mineral matter. 
     
     
         30 . The product according to  claim 1 , wherein the mineral matter is contacted with the additive that includes 500 to 3,000 ppm of glycerol or polyglycerol, relative to the dry weight of the mineral matter. 
     
     
         31 . The product according to  claim 1 , wherein the mineral matter is contacted with 0.1 to 1 mg of the additive for each m 2  of mineral matter. 
     
     
         32 . The product according to  claim 1 , wherein the mineral matter is contacted with 0.2 to 0.6 mg of the additive for each m 2  of mineral matter. 
     
     
         33 . The product according to  claim 1 , wherein the mineral matter has an average diameter, measured by a Sedigraph™ 5100, of 0.5 to 500 μm, at the supply of the air classifier in step d). 
     
     
         34 . The product according to  claim 1 , wherein the mineral matter has an average diameter, measured by a Sedigraph™ 5100, of 1 to 45 μm, at the supply of the air classifier in step d). 
     
     
         35 . The product according to  claim 1 , wherein the mineral matter has an average diameter, measured by a Sedigraph™ 5100, of 1 to 10 μm, at the supply of the air classifier in step d). 
     
     
         36 . The product according to  claim 1 , wherein the mineral matter has a percentage by weight of particles having a diameter of less than 2 μm, measured by a Sedigraph™ 5100, of between 5% and 90%, at the supply of the air classifier in step d). 
     
     
         37 . The product according to  claim 1 , wherein the mineral matter has a percentage by weight of particles having a diameter of less than 2 μm, measured by a Sedigraph™ 5100, of between 10% and 60%, at the supply of the air classifier in step d). 
     
     
         38 . The product according to  claim 1 , wherein the mineral matter of step a) is a calcium carbonate. 
     
     
         39 . The product according to  claim 1 , wherein the mineral matter of step a) is a natural calcium carbonate. 
     
     
         40 . A paint, plastic, pharmaceutical formulation, paper, paper pulp or paper coating comprising the product of  claim 1 .