Abstract

The removal of iron from leaching circuits is a common problem in the hydrometallurgical processing of non ferrous metals. Among the currently available processes, hematite precipitation is the most recommendable from an environmental point of view.This paper is concerned with the batch precipitation of hematite from ferrous sulfate solutions. One of the main objectives of the study was to determine the effect of the experimental conditions on the extent of iron precipitation as well as the purity and the particle size distribution of the precipitates. The main variables studied were temperature (180 to 220 °C), concentration of sulfuric acid (1 to 10 g/l), initial iron concentration (1 to 15 g/l), and partial pressure of oxygen (304 to 709 kPa). The results showed that an increase in the temperature produced precipitates with smaller particle sizes and lower sulfur contents. On the other hand, an increase in sulfuric acid concentration and initial iron concentration produced precipitates with larger particle sizes and higher sulfur contents. Increasing the oxygen partial pressure from 304 to 709 kPa produced a very small increase on the rate of hematite precipitation indicating that a large partial pressure of oxygen is not needed for an effective ferrous to ferric oxidation. © 2007 Elsevier B.V. All rights reserved.