Iron recovery method

#The present invention relates to a process for the precipitation of iron as hematite from a solution of Fe2(SO4)3/urea mixture containing nickel and cobalt sulphates.

#Leaching of nickel laterite ores with sulphuric acid is a widely applied process. Some recent researches indicate that when urea is added to the leach solution in sufficient amounts, metal dissolution rates and metal recoveries into the solution markedly increase. As such, the leaching time drops to one hour and metal recoveries rise above 95%.

#These improvements are due to the effect of urea on the dissolution of iron contained in the metal bearing material. When iron is attacked and forced into dissolution, other metals that are bound with iron in some kind of iron bond become easy targets for sulphuric acid and thus their dissolution rate increases markedly.

#The term ‘metal’ used herein and in the appended claims may encompass nickel, cobalt and any other metals that are normally soluble in sulphuric acid.

#Not all of steps a) through i) as detailed below must be realized in a method according to the invention but may be combined freely in a particular embodiment thereof.

#a) For the recovery of iron as hematite or usable iron oxide, the pH of the leach solution from leaching of nickel bearing material is adjusted to a pH of 2.5-3.0 by treating the solution with nickel laterite ore or nickel bearing material. No lime or limestone is used for pH adjustment in order to prevent loss of sulphuric acid through formation of gypsum.