Particulate mixtures for forming polycrystalline compacts and earth-boring tools including polycrystalline compacts having material disposed in interstitial spaces therein

An earth-boring tool, comprising

• a body;
• and
• at least one cutting element attached to the body, the at least one cutting element comprising a hard polycrystalline material consisting essentially of:
• a plurality of grains of hard material, the grains comprising:
• a first plurality of grains of hard material having a first average grain size;
• at least a second plurality of grains of hard material having a second average grain size that is at least about thirty-three (33) times larger than the first average grain size, the first plurality of grains and the at least a second plurality of grains being interspersed and interbonded to form a polycrystalline hard material;
• an interstitial material comprising at least one material selected from the group consisting of calcium carbonate, strontium carbonate, barium carbonate, and metal bicarbonates;
• and
• an additional interstitial material comprising a catalyst material selected from the group consisting of iron, nickel, cobalt, and alloys thereof;
• wherein the interstitial material is concentrated around the first plurality of grains of hard material.

A particulate mixture for forming a polycrystalline compact, the particulate mixture consisting essentially of:

• a plurality of grains of hard material, the grains comprising:
• a first plurality of grains of hard material having a first average grain size and having a coating comprising at least one material selected from the group consisting of calcium carbonate, strontium carbonate, barium carbonate, and metal bicarbonates;
• and
• a second plurality of grains of hard material having a second average grain size at least about thirty-three (33) times larger than the first average grain size, the second plurality of grains being interspersed with the first plurality of grains;
• and
• a catalyst material selected from the group consisting of iron, nickel, cobalt, and alloys thereof;
• wherein the coating is concentrated around the first plurality of grains of hard material and separates the first plurality of grains from the catalyst material;
• wherein the first plurality of grains comprises between about one-half of one percent (0.5%) and about thirty percent (30%) by volume of the particulate mixture.