Compositions, methods, and systems related to calcium carbonate blends

A method of producing a calcium carbonate blend composition, comprising:

• (a) calcining limestone to form a mixture comprising lime and a gaseous stream comprising carbon dioxide;
• (b) dissolving the mixture comprising lime in a N-containing salt solution to produce an aqueous solution comprising calcium salt;
• (c) treating the aqueous solution comprising calcium salt with the gaseous stream comprising carbon dioxide to form a composition comprising vaterite particles having an average particle size of between about 0.1-50 μm;
• (d) blending the composition comprising vaterite particles with GCC particles to form a blend comprising the vaterite particles having an average particle size of between about 0.1-50 μm and the GCC particles having an average particle size of between about 1-150 μm;
• and (e) forming a calcium carbonate blend composition comprising the blend.

A system to form a calcium carbonate blend composition, comprising:

• (i) a calcining reactor configured to calcine limestone to form a mixture comprising lime and a gaseous stream comprising carbon dioxide;
• (ii) a dissolution reactor operably connected to the calcination reactor configured for dissolving the mixture comprising lime in an aqueous N-containing salt solution to produce an aqueous solution comprising calcium salt;
• (iii) a treatment reactor operably connected to the dissolution reactor configured for treating the aqueous solution comprising calcium salt with the gaseous stream comprising carbon dioxide to form a composition comprising vaterite particles having an average particle size of between about 0.1-50 μm;
• and
• (iv) a blending station operably connected to the treatment reactor and configured for forming a blend comprising the vaterite particles having an average particle size of between about 0.1-50 μm and GCC particles having an average particle size of between about 1-150 μm and forming a calcium carbonate blend composition comprising the blend.