Process for vaterite production via the carbonation of lime, and hydrated lime and alkaline ca-containing precursors

A system for preparing a vaterite product, comprising:

• a carbonation reactor configured to carbonate a calcium rich solution or slurry comprising a calcium source, water, and at least one additive with a gaseous carbon dioxide source to form a carbonation product mixture, the carbonation reactor having a calcium-based solute slurry inlet, a carbon dioxide source feed inlet in fluid communication with a gaseous carbon dioxide source, an additive inlet, and a carbonation product mixture outlet;
• a first separator configured to separate the carbonation product mixture to provide a wet CaCO3 mixture, and an additive mixture comprising water and the at least one additive, the first separator having a carbonation product mixture inlet, a wet CaCO3 product outlet, and an additives mixture outlet, wherein the carbonation product mixture outlet of the carbonation reactor is coupled to the carbonation product mixture inlet;
• a drying unit configured to dry the wet CaCO3 mixture to produce a CaCO3 product, the drying unit having a wet CaCO3 product mixture inlet, a dry CaCO3 product mixture outlet, and a volatile components outlet, wherein the wet CaCO3 product mixture outlet of the first separator is coupled to the wet CaCO3 product mixture inlet.

A calcium carbonate composition comprising from about 40 wt % to about 100 wt % vaterite, from 0 to about 40 wt % calcium hydroxide, and less than 50 wt % calcite.