Известия высших учебных заведений: Геология и разведка (Jan 2019)
An integrated study of the electrical parameters of the samples of magnetite ores in relation to their genesis and mineral composition (on the example of the Goroblagodatskoe skarn-magnetite deposit)
Abstract
The temperature dependences of electrical resistance (at DC and AC voltage at 1 kHz frequency) of the samples of the magnetite ore and magnetite from the contact of the syenite-porphyry with the volcanic-sedimentary rocks from the Goroblagodatskoye iron-ore deposit in the temperature range 20—800 °C have been studied. The frequency dependences of the active electrical resistance and dielectric losses in the range 0,01—100 kHz have been obtained at 20 °C. For the magnetite ore and magnetite from the syenite-porphyry contact with volcanogenic sedimentary rocks in the studied temperature and frequency ranges, the relationship between electrical resistance (lgR) and dielectric losses (lgtgδ) has been revealed. The character of the relations is different, that allows to separate uniquely the magnetite ore and magnetite. The parameters of high-temperature conductivity (activation energy Eo and electrical resistance coefficient lgRo)nave been obtained. The parameters of the studied samples of pyroxene-orthoclase-magnetite, garnet-magnetite, epidote-chlorite-magnetite ores form a straight line, as if forming its different parts. The correlation between the parameters of E0 and lgRo, samples of these ores has the following form: lgRo, — 2,2—6,6 Eo. The parameters of magnetite samples from the contact of syenite porphyry with volcanogenic-sedimentary rocks also form a straight line, as if forming its different parts, with the correlation form as following: lgRo — 2,1—6,6 E0 . It has been found that with the increasing distance to the syenite intrusion, the electrical parameters of magnetite ore change: EQ increases, lgRo, decreases. For magnetite from the contact of the syenite-porphyry and volcanic-sedimentary rocks there is another picture — the further you are from the syenite-porphyries, the smaller E0 is, and the bigger the lgRo, is. The T0 temperatures, at which the electrical resistance at the constant voltage becomes equal to the active resistance at the alternating voltage for the samples of garnet-magnetite ore with the different magnetite content, P,%, have been revealed. The correlation between the T0 parameter and the magnetite content in the ore, P(Fe304 , %) = 323,4 — 47,4 ln( T0 ), R2 = = 0,93, has been established.
Keywords
