The U.S. Bureau of Mines has developed porous polymeric beads containing immobilized biological materials for removing metal contaminants from mining and mineral processing wastewaters. The beads, designated bio-fix beads, are fabricated from readily available raw materials. The beads exhibit excellent handling characteristics in conventional equipment and demonstrate long-term chemical and physical stability. Beads containing sphagum moss were utilized in a three-column fixed-bed circuit to remove cadmium, manganese, and zinc from a wastewater emanating from an inactive zinc mining operation. The ph 4.0 Wastewater contained 0.06 Mg/l cd, 6.0 Mg/l mn, and 12.0 Mg/l zn. Over 99 pct of the cadmium, manganese, and zinc were removed from several hundred liters of wastewater in continuous tests, and national drinking water standards were consistently met. Flow rates ranged from 20 to 30 bed volumes (bv)/hr while processing 60 to 80 bv of solution each cycle. The loaded bio-fix beads were stripped of metal values with a dilute sulfuric acid eluant. Enriched eluates containing over 100 times as much cadmium, manganese, and zinc as the original wastewater were obtained. These eluates were further concentrated using conventional hydrometallurgical techniques, and products acceptable for subsequent metal refinement by a zinc-processing operator were produced.
Proc. Western Regional Symp. on Mining & Mineral Proc. Wastes, Berkeley; SME, 1990, PP. 279-286