Patent ID: 8359886

Claim:
A process for producing proppants, the process comprising: providing an amorphous spherical glass particulate derived by fusing and quenching a waste byproduct of mining in the form of an aluminosilicate mineral, the aluminosilicate mineral selected from the group consisting of rhyolite, theoliite, olivine, basalt, andesite and combinations thereof; heating the amorphous spherical glass particulate to a temperature greater than 600° C. for a predetermined time such that one or more crystalline phases nucleates and grows within the amorphous spherical glass particulate and produces a partially devitrified glass particulate; and cooling the devitrified glass particulate to ambient temperature; wherein the cooled devitrified glass particulate has a Vickers indentation fracture resistance (VIFR) greater than 1.2 MPa·√{square root over (m)}; wherein said VIFR is determined by the expression: VIFR=0.1706( H·√{square root over (a)} )·Log(4.5 a/c ) where: H is a Vickers hardness value of said glass particulate; a is a diagonal length of an indentation produced from a Vickers hardness test; and c is a crack length extending from the indentation produced from the Vickers hardness test.