Attempts to Stabilize Blasting Debris with Cement

2 Attempts to Stabilize Blasting Debris with Cement 

Salt and colleagues [4] have investigated using accelerating additives to counteract the effects of lead and other heavy metals in the spent abrasive on the set, strength, and leaching of mortars made with portland cement and used abrasive debris. Some of their findings are summarized here  

The amount of lead leaching was strongly dependent on the pH of the liquid after being mixed with the solid lead with a pH below 8 began to leach, and the amount of lead leaching rose dramatically with each sequential drop in pH. 

Cadmium also began leaching when the pH of the liquid after being mixed with the solid dropped below 8 the amount leaching reached a maximum of 6 and then fell off as the pH continued to drop. This could be an artificial maximum, however, because the amount of cadmium was low to begin with it could be that by the time the pH had dropped to 5, almost all the cadmium in the sample had leached out. 

The authors suggest that the ability of the calcium matrix to resist breakdown (due to acidification) in the concrete is important for the stabilization of lead and cadmium. 

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