Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COP...

Iron ore occurrences are situated on the south-eastern slopes of the Medvednica Mountain. They occur as discontinous, decameters long and 2-3.5 m thick bedded, poorly mineralized (15-35 % Fe) lenses. A narrow, 6 km long, ore zone strikes NE-SW from Tisova Peć to Pustodol-Adolfovac. It is spatially and genetically bounded to the basic volcanogenic-sedimentary series (SEDEX-type), metamorphosed i...

Chromite is widely distributed in the east and southeast of Afghanistan, especially in Logar Province. Chromite mineralization is podiform-type and is hosted in the stratigraphically lowest ultramafic rocks of the Logar Ophiolite Complex. This ophiolite complex represents a remnant of an early Cretaceous oceanic crust that was thrusted over a late Permian to Mid-Jurassic platform-type sequence ...

heavy metal concentration in the soils and sediments has increased worldwide during the last century due to the mining, smelting, and industrial activities. the forumad chromite deposit is located in the sabzevar ophiolitic complex (soc), with a long history of mining activities, yet very little is known about the heavy metal contamination in its surrounding environment. in this research work, ...

electron-probe microanalyses and scanning electron microscopy of chrornitites from some ultramafic members of neyriz ophiolite indicate that sulifides of platinum- group minerals (pgms) occur as solid inclusions in chromite grains. laurite with the general formula of (ru ,os ,lr ) s , and erlichmanite are the main identified sulfide phases. the pgms occur as 4 to 20 microns euhedral to rectangu...

introduction the central alborz in eastern mazandaran province is host to the most important carbonate-hosted fluorite deposits in iran, such as pachi-miana, sheshroodbar, era and kamarposht. in these deposits, mineralization occurs in the upper parts of the middle triassic elika formation (vahabzadeh et al., 2009 and references therein). these deposits have long been studied, and various model...

The paper provides results of a detailed mineralogical study some chromitite ores from two deposits in the Southern Urals Kazakhstan: Almaz-Zhemchuzhina and Geofizicheskoe-VII. It is revealed that main ore minerals are Cr-spinel with high Cr# (Cr/(Cr + Al) = 0.8–0.83), as well serpentine chlorite, replacing primary olivine. Chromium spinel grains contain mineral inclusions, which distributed ra...

This paper documents the exploration significance of Ag/Au, Au/Cu, Cu/Mo and (Ag×Au)/Cu×Mo) ratios of the supra-ore and sub-ore halos versus fluid inclusion evolution for 24 Cu, 6 Cu- Mo and 10 Cu-Au porphyry deposits worldwide. The ratios are based only on the economic and mineralized hypogene alteration zones. The results indicate that (Ag×Au)/(Cu×Mo), Au/Cu and Cu/Mo ratios increase with dec...