Processed slag and methods for producing same

Abstract

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective removal of carbonate-forming alkaline earth elements from slag. The resulting processed slag has a reduced tendency to form carbonate salts on environmental exposure, and reduced tendency to fracture due to the formation of such salts. The lixiviant used can be regenerated and recycled for use in subsequent iterations of the process.

What is claimed is: 
     
         1 . A processed slag, wherein the processed slag is produced by selective removal of an alkaline earth element from a slag, and wherein the processed slag comprises less than 60% of the alkaline earth element content of the slag. 
     
     
         2 . The processed slag of  claim 1 , wherein the processed slag comprises less than 40% of the alkaline earth element content of the slag. 
     
     
         3 . The processed slag of  claim 1 , wherein the processed slag comprises less than 20% of the alkaline earth element content of the slag. 
     
     
         4 . The processed slag of  claim 1 , wherein the processed slag is characterized by having a reduced carbonate content following an environmental exposure relative to that of the slag following the environmental exposure. 
     
     
         5 . The processed slag of  claim 1 , wherein the processed slag, following an environmental exposure, is characterized by having improved resistance to compressive stress or lateral stress relative to that of the slag following the environmental exposure. 
     
     
         6 . A construction material comprising a processed slag, wherein the processed slag is produced by selective removal of an alkaline earth element from a slag, and wherein the processed slag comprises less than 60% of the alkaline earth element content of the slag. 
     
     
         7 . The construction material of  claim 6 , wherein the construction material is selected from the group consisting of concrete, concrete sand, concrete aggregate, and asphalt aggregate. 
     
     
         8 . The construction material of  claim 6 , wherein the construction material is selected from the group consisting of road bed material, railroad track bed material, and fill material.