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Ground calcium carbonate compositions having narrow particle size distributions and a method for producing the compositions. The method involves forming a substantially dispersant-free calcium carbonate suspension, wet-grinding the suspension, and aging the suspension. The method does not require th

Ground calcium carbonate compositions having narrow particle size distributions and a method for producing the compositions. The method involves forming a substantially dispersant-free calcium carbonate suspension, wet-grinding the suspension, and aging the suspension. The method does not require the use of classification equipment and the aging process does not require heating.

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1. A method for reducing the width of a particle size distribution comprising: (a) forming a substantially dispersant-free aqueous suspension of a ground natural calcium carbonate; (b) wet-grinding the suspension to produce a first calcium carbonate composition, wherein the calcium carbonate par

1. A method for reducing the width of a particle size distribution comprising: (a) forming a substantially dispersant-free aqueous suspension of a ground natural calcium carbonate; (b) wet-grinding the suspension to produce a first calcium carbonate composition, wherein the calcium carbonate particles in the first calcium carbonate composition are characterized by a first steepness ratio; and (c) aging the first calcium carbonate composition at a temperature below 35° C. to produce a second calcium carbonate composition, wherein the calcium carbonate particles in the second calcium carbonate composition are characterized by a second steepness ratio, and further wherein the second steepness ratio is smaller than the first steepness ratio. 2. The method according to claim 1, wherein the second steepness ratio is below about 1.9. 3. The method of claim 1, wherein the suspension is aged at a temperature below about 30° C. 4. The method according to claim 1, wherein the suspension is aged at a temperature between about 20° C. and about 25° C. 5. The method according to claim 1, where the suspension is aged for a time period of between about 1 hour and about 24 hours. 6. The method according to claim 1, where the suspension comprises less than about 30% calcium carbonate by weight. 7. The method according to claim 1, where the suspension comprises between about 23 and about 25% calcium carbonate by weight. 8. The method according to claim 1, wherein no classification equipment is used. 9. A method for reducing the width of a particle size distribution comprising: (a) forming a substantially dispersant-free aqueous suspension of a ground natural calcium carbonate; (b) wet-grinding the suspension to produce a first calcium carbonate composition, wherein the calcium carbonate particles in the first calcium carbonate composition are characterized by a first steepness ratio; and (c) aging the first calcium carbonate composition in the absence of heating to produce a second calcium carbonate composition, wherein the calcium carbonate particles in the second calcium carbonate composition are characterized by a second steepness ratio, and further wherein the second steepness ratio is smaller than the first steepness ratio. 10. The method according to claim 9, wherein the second steepness ratio is below about 1.9. 11. The method according to claim 9, where the suspension is aged for a time period of between about 1 hour and about 24 hours. 12. The method according to claim 9, where the suspension comprises less than about 30% calcium carbonate by weight. 13. The method according to claim 9, where the suspension comprises between about 23 and about 25% calcium carbonate by weight. 14. The method according to claim 9, wherein no classification equipment is used after wet-grinding and before aging.