Amending promotion of Zn in contaminated soil using red-mud based materials

Red mud composite particles were made up of red-mud (waste of alumina refinery). The particles have been applied as remediation material for metal contaminated soil. Leeks were planted for pot experiments. The promotions of transform, chemical fixation and absorption inhibition of Zn were analyzed. In this research, composite particles relieved the increase effect of soil pH that caused by strong alkaline in red mud. With the content of phosphate in particles increasing, the remediation effect was better. When adding 5% particles, the largest increase ratio of residual was 19.62% and the biggest decrease of ion exchange was 100%. All of the materials could inhibit the absorption. The inhibition rose from 50.02% by red mud powder to 64.90% by 50% phosphate composite particle. It is a new way of resource utilization for red mud by granulation under partly hydration.