Demetallized slag for abrasives and/or roofing granules and related methods

A plurality of steel slag particles, wherein:

• at least 90% of the steel slag particles have a size that is less than or equal to 1.25 mm and greater than or equal to 0.14 mm;
• a metallic iron and an iron (II) oxide (FeO) content of the steel slag particles, by weight, is less than or equal to 5%;
• an iron (III) oxide (Fe2O3) content of the steel slag particles, by weight, is greater than or equal to 5%;
• a manganese (II) oxide (MnO) content of the steel slag particles, by weight, is greater than or equal to 5%;
• and
• the steel slag particles comprise electric arc furnace slag that is substantially free of ladle slag;
• and
• the steel slag particles comprise calcium oxide (CaO), silicon dioxide (SiO2), aluminum oxide (Al2O3), and magnesium oxide (MgO) and wherein the aluminum oxide content of the steel slag particles, by weight, is at least 10%.

An abrasive blast media comprising:

• a plurality of steel slag particles, wherein:
• at least 90% of the steel slag particles have a size that is less than or equal to 1.25 mm and greater than or equal to 0.14 mm;
• a metallic iron content of the steel slag particles, by weight, is less than or equal to 10%;
• an iron (III) oxide (Fe2O3) content of the steel slag particles, by weight, is greater than or equal to 5%;
• and
• the steel slag particles have an angular morphology such that in a cleaning process in which the abrasive blast media is ejected at a pressure of 100 pounds per square inch from a No. 4 blast nozzle positioned 18 inches away from a surface of a hot rolled carbon steel substrate that includes mill scale, the abrasive blast media is configured to clean the surface of the hot rolled carbon steel substrate at a cleaning rate of at least 135 square feet of the surface per hour (ft2/hr) such that the surface complies with SSPC-SP 10.