Abstract: The acidic magnetite concentrate from Pingchuan,Gansu Province,has a relatively coarse particle size,with a
TFe grade of 65. 60% and a main impurity SiO2 content of 4. 68%. To evaluate the feasibility of processing this iron concentrate
into ultra-pure iron concentrate,mineral processing test studies were conducted based on process mineralogy research. The results
indicate that:① Iron in the main iron mineral,magnetite,accounts for 96. 77% of the total iron. The overall relationship
between the main gangue minerals (titanite,albite,quartz,etc. ) and magnetite is relatively simple. Abundant magnetite monomers
are visible,while gangue mineral monomers are occasionally seen. Magnetite and gangue minerals exhibit both intergrowth
and inclusions,with most intergrowth contact surfaces being relatively straight and easily liberated. The magnetite itself is of
very high purity,containing only minor speckled distributions of Si and Al elements. Impurity elements Si,Al,Ca,and Mg are
mainly distributed within the gangue minerals. These process mineralogy characteristics indicate potential for producing ultrapure
iron concentrate from this sample. ② The sample,ground to a fineness of 95% passing 0. 038 mm,was processed using a
flowsheet comprising one roughing and two cleaning stages of low-intensity magnetic separation (magnetic field intensities of
128,88,and 60 kA/ m respectively) followed by one roughing and two cleaning stages of open-circuit reverse flotation. This
yielded an ultra-pure iron concentrate with yield of 33. 39%,iron grade of 71. 76%,and SiO2 content of 0. 28%,as well as a
high-purity iron concentrate with yield of 56. 48%,iron grade of 70. 14%,and SiO2 content of 1. 20%. The test achieved excellent
separation performance,significantly enhancing the economic value of the plant′s iron concentrate.

Key words: ultra-pure iron concentrate,process mineralogy,grinding,monomer dissociation,low intensity magnetic separation,
cationic reverse flotation