Abstract: Due to low copper recovery in magnetic separation of tailings in a dressing plant of Shandong，the concentration test researches are made.The results showed that with the grinding fineness of -0.074 mm 70%，copper concentrate grading at 16.50% with a copper recovery of 83.88% was obtained by choosing isoamyl xanthate as a collector of chalcopyrite instead of ethyl xanthate，and adding the appropriate amount of water glass as dispersant of sludge.In the case of copper grade declining by 0.52%，the copper recovery increased by 38.21% with good separation index achieved.

Key words: Low grade copper mine, Recovery rate, Isoamyl xanthate