Self-magnetization of pyrite and its application in flotation
(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)
Abstract: Pyrite is a special weakly magnetic mineral containing Fe(II). Its self-magnetization only by adjusting slurry temperature and pH value was able to enhance its magnetism, producing the so-called the magnetized pyrite, which was further used as magnetic seeds in the flotation of pyrite ore to promote flotation recovery. Tests, such as self-magnetization, vibrating sample magnetometer (VSM), XPS, size analysis and flotation were carried out. The optimal conditions of the pyrite self-magnetization were pulp pH of 11.81 and temperature of 65 °C. The magnetized pyrite was characteristic of the valence change of elemental iron, resulting in stronger magnetism of the magnetized pyrite than that of the original pyrite. Then, this magnetized pyrite was applied to the magnetic seeding flotation (MSF) of pyrite ore. It was found that the recovery of pyrite flotation grew with the increase of magnetic susceptibility of the magnetic seeds-the magnetized pyrite; and the proper dosage of the magnetized pyrite was 100 g/t. The reason behind the increased recovery lies in that the magnetized pyrite promoted the magnetic agglomeration between fine pyrite particles; and the fact that the stronger the magnetism of the magnetized pyrite, the larger the aggregate size, indicates that the agglomeration is somewhat in line with the flotation, also confirming that the MSF is more suitable for fine particles than traditional flotation.
Key words: pyrite; self-magnetization; magnetized pyrite; magnetic agglomeration; magnetic seeding flotation