Purification of feldspar from iron oxide impurities using nitric acid in presence of ammonium biuoride

Abstract

The main objective of this study is focused on the mechanical preparation of Algerian crude feldspar with a view to extract the information about the comminution and the coloring iron rate distribution, on the one hand, and to remove the iron oxides, on the other hand, main impurities of crude feldspar by magnetic separation, flotation and more particularly by chemical leaching. In this process, the nitric acid and dithionite as reducing agent are used to replace sulfuric acid whose the application tests have yielded negative results. Research results shows that using a nitric acid in a reducing medium as ammonium bifluoride (HF_,NH₄F) process is effective and pushes the degree of iron oxides (Fe₂O₃) removal around 0.01\%. The hydro-metallurgical process applied especially to size fractions [-0.8 + 0.1] mm intended for the glass industry previously undergo a high intensity magnetic field reduces iron levels up to 0.054 \% with a yields in terms of weight of 58.32\% compared to those of all comers.