Abstract: In order to solve the problem of sludge in the separation of a lowgrade,highmud and highmagnesium refractory nickel sulfide ore in Gansu province,based on the study of process mineralogy,a preflotation deslimsand flotation process was adopted to recover nickel,which effectively reduced the interference of highmagnesium argillaceous minerals on nickel flotation.The nickel concentrate 1 obtained by the closedcircuit process was containing 2.95% nickel and the nickel recovery was 4.62%.Nickel concentrate 2 contains 5.85% nickel and the recovery of nickel is 77.38%.The total nickel recovery was 82.00%.The research results have reference significance for the development and utilization of high magnesium and low grade nickel sulfide resources.

Key words: low grade nickel sulphide ore,high MgO,argillization,preliminary desliming,nickel recovery from mud and sand respectively