The susceptibility property and the heat treatment of tourmaline from Houxianyu,Liaoning Province

The tourmaline from Houxianyu,Liaoning Province was heated under different temperatures in oxidizing condition.The structure and phase changing after heating treatment were analyzed by optical microscope,XRF,XRD and IR spectroscopy.Magnetic susceptibility was also determined by the magnetic susceptibility testing instrument.The results showed that the black tourmaline was dravite.Under the temperature of 700℃the structure of tourmaline began to change and transformed to anorthite and hematite under the temperature of800℃,sintering phenomenon was observed at the same time.The magnetic susceptibility of tourmaline had a negative correlation with the heating temperature.The low-frequency magnetic susceptibility got to lowest as33.6×10-6cm3/g at 900℃.Its magnetic decrease was related to the phase and the ionic valency change.