摘要 |
<p>The present invention, therefore, provides stage crushing method for recovering precious metals from slag produced by a coal burning furnace or boiler comprising: a plurality of crushing steps, wherein each crushing step produces slag particles having successively smaller particle diameter sizes, said crushing steps continued until a final desired particle diameter sized is obtained; wherein each of said crushing steps is followed by suspending said crushed slag particles in a liquid medium to form a slurry of light-weight particles and heavy-weight particles and allowing the crushed slag particles within the slurry to separate, based on weight of the particles, thereby forming a light-weight particle population and a heavy-weight particle population; wherein each suspending step is followed by removing said light-weight particles from said slurry, such that said slurry consists of substantially heavy-weight particles; and collecting said heavy-weight particles.</p> |