Abstract: The sulfur minerals in a concentrator of TNMG are mainly pyrite and magnetite.Sulfur concentrate after re-selected in the production.It is difficult to meet the 90% target for total sulphur plus iron in sulfur concentrate.Sulfur concentrate after burning acid to obtain low grade of red powder iron,added value is not high,seriously affect the economic benefits of enterprises.n order to improve the quality and reduce impurities of sulfur concentrate,according to the good floatability of pyrite.Magnetic yellow iron has poor floatability and weak magnetic properties,Step by step flotation process was adopted in the laboratory.In other words,the process of recovering pyrite with good floatability is given priority,and the process of recovering pyrite with floating tail magneto-flotation is realized,which realizes the efficient recovery of pyrite and pyrrhotite.In order to further verify the rationality of the fractional flotation process,a part of sulfur crude concentrate pulp was separated on site for continuous separation test.The total sulfur concentrate obtained by continuous separation test contained 46.31% sulfur,91.60% total sulfur plus total iron,and 80.28% sulfur recovery.The sulfur concentrate in the test site contains 39.67% sulfur,80.52% total sulfur plus total iron,and 73.94% sulfur recovery.The total sulfur and total iron content of sulfur concentrate was 11.08 percentage points higher and the sulfur recovery rate was 6.34 percentage points higher.The results of continuous selection test provide the technical and theoretical basis for the reselection process of crude sulfur.

Key words: pyrite, pyrrhotite, step by step flotation, continuous selection test