A method for treating heavy metals-containing wastes to preserve the ecosystem of seawater

摘要

PURPOSE: A method for stabilizing wastes containing toxic heavy metals from iron/steelmaking industries, such as slag, sludge and dust, is provided to prevent heavy metal release that would disrupt submarine echo system in coastal iron/steelmaking industrial complex. CONSTITUTION: The stabilization method of wastes containing toxic heavy metals comprises the step of (i) blending wastes, solidifying agent and hydraulic binder in a ratio 100:20:4-6; (ii) shaping into clay blocks, and then hardening them in a kiln. Portland cement is used as a solidifying agent, and the hydraulic binder is composed of CaO 59.5-63.0wt.%, SiO2 19.5-22.5wt.%, Al2O3 6.0-8.0wt.%, MgO 2.5-2.9wt.%, Fe2O3 2.5-2.9wt.%, SO3 2.3-3.0wt.% and balance residual portion. The obtained block-shaped waste has pressure strength of about 30 to 80kg/cm¬2.