Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods make use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

Concrete may be melted to form a glass product. Methods and batch compositions including concrete may be used to produce amorphous silica materials including, but not limited to, glass, container glass, fiber glass, glass bead, glass spheres, sheet or plate glass, glass aggregate, glass sand, abrasives, proppants, foamed glass, and manufactured glass articles. The initial processing steps include preparing a melt batch comprising concrete and, optionally, other components, melting the melt batch, and cooling the melted melt batch. Further processing steps may be utilized to produce the glass article.

Concrete may be melted to form a glass product. Methods and batch compositions including concrete may be used to produce amorphous silica materials including, but not limited to, glass, container glass, fiber glass, glass bead, glass spheres, sheet or plate glass, glass aggregate, glass sand, abrasives, proppants, foamed glass, and manufactured glass articles. The initial processing steps include preparing a melt batch comprising concrete and, optionally, other components, melting the melt batch, and cooling the melted melt batch. Further processing steps may be utilized to produce the glass article.

A method for making a low cost, lightweight carbon aggregate from coal at, above, or below atmospheric pressure, and a lightweight concrete composition utilizing the lightweight carbon aggregate is described.

A method for making a low cost, lightweight carbon aggregate from coal at, above, or below atmospheric pressure, and a lightweight concrete composition utilizing the lightweight carbon aggregate is described.

An ultra-white granular silica-based filler comprises at least 99.5 wt. % silica, wherein the crystal structure of the silica is such that the silica-based filler comprises 40 to 80 wt. % cristobalite, 1 to 25 wt. % tridymite, 2-60 wt. % quartz and <5 wt. % amorphous silica, wherein the temperature of the ultra-white granular silica-based filler is no higher than 50° C. and further wherein the ultra-white granular silica-based filler exhibits an L* value in the CIELAB color space of 95-98. In addition, an ultra-white powder filler is obtained by milling, grinding or comminuting the ultra-white granular silica-based filler. The ultra-white powder filler exhibits an L* value in the CIELAB color space of 95-98.5.

An ultra-white granular silica-based filler comprises at least 99.5 wt. % silica, wherein the crystal structure of the silica is such that the silica-based filler comprises 40 to 80 wt. % cristobalite, 1 to 25 wt. % tridymite, 2-60 wt. % quartz and <5 wt. % amorphous silica, wherein the temperature of the ultra-white granular silica-based filler is no higher than 50° C. and further wherein the ultra-white granular silica-based filler exhibits an L* value in the CIELAB color space of 95-98. In addition, an ultra-white powder filler is obtained by milling, grinding or comminuting the ultra-white granular silica-based filler. The ultra-white powder filler exhibits an L* value in the CIELAB color space of 95-98.5.

Methods for increasing the hardness of aggregate include applying a hardener to the aggregate. The hardener may react with a material of the aggregate and/or a material on a surface of the aggregate. For example, an alkali metal silicate, such as lithium polysilicate, or a colloidal silica may chemically react with calcium oxide and/or calcium hydroxide of an aggregate or on an aggregate to create cementitious material, which may at least partially fill pores in the surface of the aggregate, harden an existing microtexture of the aggregate and/or enhance the microtexture of the aggregate. These characteristics may enhance frictional characteristics, the wear characteristics and the durability of the aggregate, and of any structures formed from composite materials that include the aggregate.

Methods for increasing the hardness of aggregate include applying a hardener to the aggregate. The hardener may react with a material of the aggregate and/or a material on a surface of the aggregate. For example, an alkali metal silicate, such as lithium polysilicate, or a colloidal silica may chemically react with calcium oxide and/or calcium hydroxide of an aggregate or on an aggregate to create cementitious material, which may at least partially fill pores in the surface of the aggregate, harden an existing microtexture of the aggregate and/or enhance the microtexture of the aggregate. These characteristics may enhance frictional characteristics, the wear characteristics and the durability of the aggregate, and of any structures formed from composite materials that include the aggregate.

A method for making a low cost, lightweight carbon aggregate from coal at, above, or below atmospheric pressure, and a lightweight concrete composition utilizing the lightweight carbon aggregate is described.