The study of minero-petrographical characteristics and the subsequent textural and structural characterization of an ore mineral represents the first step of each industrail processing whose aim is the beneficiation of each valuable mineral phase present inside the ore. Analytical, mineralogical and petrographical, chemical and mutlispectral image analyses based investigations, applied to eclogitic ore samples deriving form "in situ" sampling campaigns, enabled to point out some textural and structural aspects characteristics of ore litotypes belonging to eclogitic-amphibolitic dikes. Such dikes are characterized by a paragenesis constituted by siliceous gangue: pink garnet in the terms pyrope, green pyroxene of omphacitic type; monocline amphibole (from blu-green to blu-violet) belonging to the glaucophane-riebekite alkaline series, calcic amphibole (actinolite) and accessory "useful titanium minerals" as rutile, "pseudolilmenite", ilmenite and sphene. In the beneficiation process applied to such a ore is of preliminary importance to establish a strategy in order to obtain a recovery of high quality "mono-minerals concentrates" as rutile, "pseudolimenite", ilmenite and pheno. To reach this goal is thus necessary to develop a preliminary study of the textural, structural, petrochemical and minerochemical characteristics of the samples. Different ore samples (eclogitic rocks), resulting from sampling campaigns carried out in the Piampaludo area (Sassello district: Savona, Northern Italy) were examined. The titanium minerals are present as rutile (TiO2), "pseudoilmenite" and sphene (CaTiSiO5). The TiO2 grade contained in the ores is on the average equal to 5.4%, on the contrary Fe2O3 e l' FeO are about the 4.0% and the 14.3%, respectively. The Titanium is concentrated, mainly, in the rutile, quite pure (TiO2 > 98%). The rutile is present as intergrowths or containing exolution of phase quite easy to distinguish and less rich in TiO2 (92.1%) and containing FeO (3.4%), Al2O3 (1.4%) and V2O3 (0.5%). Such a phase ("pseudoilmenite") can be also found as inclusions in the siliceous gangue. Sometimes isolated sphene cristals with a variable composition are present. In such a ore could be of particular interest to i dentify a procedure able to analyze and to discriminate each mineral species, this fact due: i) the possible great variability of Ti inside the mineral phases of interest; ii) the influence that such a different content produces on the reflectivity characteristics of the phases themselves, strongly modifying the spectral response of the surfaces. Aim of the present study was to utilize the modern color image processing techniques (CIP) in order to emphasize as, by such a technique, the morphological and morphometrical aspects of interest for the titanium minerals may be derived, togetehr with the analytical data acquired by the classical methods (chemical, microscopical and electronic microprobe analyses). The different approaches were compared and integrated to derive useful information about the rutile, the rutile-"pseudoilmenite" and the sphene for the next beneficiation strategies. All the procedures have been developed starting from image analysis data obtained from polished sections acquired by means of standard optical reflected light microscope. The procedure pointed out enabled to build morphological maps evidencing the shape and distribution relationship among the different phases and the compositional relationships inside the species of interest.
Digital process mineralogy applied to titanium minerals characterization / Bonifazi, Giuseppe; R., Gorga. - STAMPA. - (1994), pp. 1-15. (Intervento presentato al convegno 1994 AIME-SME Annual Meeting and Exibit tenutosi a Albuquerque, NM).
Digital process mineralogy applied to titanium minerals characterization
BONIFAZI, Giuseppe;
1994
Abstract
The study of minero-petrographical characteristics and the subsequent textural and structural characterization of an ore mineral represents the first step of each industrail processing whose aim is the beneficiation of each valuable mineral phase present inside the ore. Analytical, mineralogical and petrographical, chemical and mutlispectral image analyses based investigations, applied to eclogitic ore samples deriving form "in situ" sampling campaigns, enabled to point out some textural and structural aspects characteristics of ore litotypes belonging to eclogitic-amphibolitic dikes. Such dikes are characterized by a paragenesis constituted by siliceous gangue: pink garnet in the terms pyrope, green pyroxene of omphacitic type; monocline amphibole (from blu-green to blu-violet) belonging to the glaucophane-riebekite alkaline series, calcic amphibole (actinolite) and accessory "useful titanium minerals" as rutile, "pseudolilmenite", ilmenite and sphene. In the beneficiation process applied to such a ore is of preliminary importance to establish a strategy in order to obtain a recovery of high quality "mono-minerals concentrates" as rutile, "pseudolimenite", ilmenite and pheno. To reach this goal is thus necessary to develop a preliminary study of the textural, structural, petrochemical and minerochemical characteristics of the samples. Different ore samples (eclogitic rocks), resulting from sampling campaigns carried out in the Piampaludo area (Sassello district: Savona, Northern Italy) were examined. The titanium minerals are present as rutile (TiO2), "pseudoilmenite" and sphene (CaTiSiO5). The TiO2 grade contained in the ores is on the average equal to 5.4%, on the contrary Fe2O3 e l' FeO are about the 4.0% and the 14.3%, respectively. The Titanium is concentrated, mainly, in the rutile, quite pure (TiO2 > 98%). The rutile is present as intergrowths or containing exolution of phase quite easy to distinguish and less rich in TiO2 (92.1%) and containing FeO (3.4%), Al2O3 (1.4%) and V2O3 (0.5%). Such a phase ("pseudoilmenite") can be also found as inclusions in the siliceous gangue. Sometimes isolated sphene cristals with a variable composition are present. In such a ore could be of particular interest to i dentify a procedure able to analyze and to discriminate each mineral species, this fact due: i) the possible great variability of Ti inside the mineral phases of interest; ii) the influence that such a different content produces on the reflectivity characteristics of the phases themselves, strongly modifying the spectral response of the surfaces. Aim of the present study was to utilize the modern color image processing techniques (CIP) in order to emphasize as, by such a technique, the morphological and morphometrical aspects of interest for the titanium minerals may be derived, togetehr with the analytical data acquired by the classical methods (chemical, microscopical and electronic microprobe analyses). The different approaches were compared and integrated to derive useful information about the rutile, the rutile-"pseudoilmenite" and the sphene for the next beneficiation strategies. All the procedures have been developed starting from image analysis data obtained from polished sections acquired by means of standard optical reflected light microscope. The procedure pointed out enabled to build morphological maps evidencing the shape and distribution relationship among the different phases and the compositional relationships inside the species of interest.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
