Abstract: In order to fully reduce the environmental risk caused by the utilization of cyanide tailings as backfill aggregate after pyrolysis，aiming at the harmless problem of cyanide tailings under medium and low temperature conditions，the pyrolysis of cyanide tailings at medium and low temperature was studied by using rotary furnace. The results showed that under the conditions of pyrolysis temperature 350 ℃，and py⁃ rolysis time 5.0 h，the removal rates of total cyanide and easily released cyanide were the highest，reaching 99.21% and 98.39%，respectively，and the easily released cyanide was the lowest，reaching 0.004 mg/L; considering the control of operation cost in actual operation，it is suggested that the pyrolysis time should be controlled at about 1.0 h and the pyrolysis temperature at 350 ℃，which can also obtain better cyanide breaking effect. In addition，except under the pyrolysis condition of 250 ℃ and 0.5 h，the cyanide concen⁃ tration in the toxic leaching solution of cyanide residue is not up to the standard，the toxic leaching indexes of cyanide residue under the other pyrolysis conditions all meet the pollution control requirements of back⁃ fill aggregate.

Key words: cyanidation tailings, pyrolysis, medium and low temperature, cyanide breaking, backfill ag? gregate