Heterogeneity in relation to electrical and mineralogical properties of hematitic sandstone samples

Electrical properties of mixtures of composite materials are sensitive to texture between grains. Electrical measurements of hematite and sandstone composite mixture were performed in the frequency range (5 × 10⁻⁴ Hz–10⁵ Hz). This study is a trial to give more detailed information upon the effect of electrical properties and their relation to the ore composite mixture, its geochemical and spectrographic analyses. The composite mixture of the samples displays some similarity in the frequency-dependent response of the electrical properties that follow Jonscher's universal law. The frequency dependence of electrical conductivity indicates that the sample behaves as a semiconductor material at relatively high frequencies. The spectra of the measured electrical properties vary strongly with the change of the concentration of the conductive elements and the texture of the specimens. The main change of the electrical properties is related to the conductor (saturation) concentration. This change does not increase monotonically with the increase in the conductor (saturation) concentration which may be attributed to the degree of heterogeneity between the grains (and texture). The interface between the grains controls the relatively low frequencies, whereas the bulk grain dominates the relatively high frequencies. The heterogeneity of the samples is an effective component in controlling the electrical properties of the composite mixtures.