Rare earth elements in the Chador-Malu iron ore mine: Statistical analysis of ΣREE grade-variate in the northern orebody, REE enrichment through beneficiation process, and Th contents

The Chador-Malu iron ore deposit (Bafq district, Central Iran) is the largest known iron oxideapatite deposit in Iran (pre-mining reserve of 400 Mt). This type of deposits may contain economical enrichments of REE in their phosphate mineralogy, which is predominantly comprised of apatite. In present work, the northern orebody of the Chador-Malu deposit, as well as the phosphate-rich tail of the beneficiation plant have been sampled in order to provide information on the REE contents of the ore, and to evaluate REE enrichment through beneficiation process.Samples from individual apatite crystals were collected to demonstrate highest REE concentrations.Information on the Th contents of the samples has also been provided which is crucial to potential REE production purposes. Chemical analysis was performed at Labwest Mineral Analysis, Western Australia, using ICP-MS and ICP-OES. The statistical distribution of ΣREE grade-variate in the chador-Malu deposit was similar to that of geochemical data of rare or precious metals which are characterized by a positive skewness. The tri-parameter logarithm transformation eliminated this skewness and then the mean ΣREE grade of the ore samples was calculated as 1235.2 ppm. The REE were enriched in the phosphate-bearing tail of the beneficiation plant by 2900 ppm and thus it could be considered a feasible resource for REE production. Apatite samples contained up to 1.4 wt% REE and 83.4 ppm Th. The Th content in the phosphate-rich tail samples was approximately 30 ppm and higher than most of the ore samples.

Keywords:

Chador-Malu , Rare earth elements , Statistical Analysis