Produção de pellet feed a partir de lamas

Abstract

This study investigated the possibility of producing an iron concentrate meeting thespecifications of Samarcos pellet feed from a representative sample of the 101.6mm (4 inches) cyclone overflow of Concentrator I. This sample, designated as plant slimes, containing 49.65% iron, d50 equal to 5m and percentage of slimes (fraction passing 10m) equal to 71.22%. The technological tests involved the following steps: classification (in microdesliming drum), determination of the dispersion degree, and flotation. Microdesliming proved to be an efficient method of classification. The results showed that the dispersants sodium hydroxide, sodium hexametaphosphate, and sodium polyacrylate achieved similar levels of dispersion and also that the dispersants sodium hexametaphosphate and sodium polyacrylate are the most effective reagents to promote dispersion of the alumina and phosphorus bearing minerals. Flotation tests, following the factorial design of experiments (DOE), showed that the factor etheramines dosage was the most significant among the factors investigated for the response variables silica content in the concentrate and metallurgical recovery. Flotation tests with addition of the dispersants sodium hexametaphosphate and sodium polyacrylate presented increased metallurgical recovery concurrently with increased silica content in the concentrate. The flotation kinetics test proved the need of increasing the flotation time to achieve a silica content in the concentrate meeting the specification of Samarcos direct reduction pellet feed (SiO2 <1.13%).