Processing used sand blasting medium

摘要

A method of processing zinc- and/or lead-containing sand blasting medium for reuse involves (a) drying and then classifying into extremely coarse (above 1.5-2.0 mm size), coarse and fine (below 0.2-0.5 mm size) fractions; (b) heat treating the coarse fraction in the absence of air to separate surface-adhering zinc and/or lead particles, decompose binder particles and release other heavy metal particles; (c) discharging the resulting gaseous products for waste gas treatment; (d) mechanically treating the residual coarse fraction material to separate the zinc- and/or lead-rich small particles from the coarser reusable sand blasting medium.