Conference Dates

April 29-May 4, 2018


Phosphorus has its main application in the production of phosphoric acid, being the apatite series its main ore. The Brazilian main phosphorus reserves are igneous, as is the case of Catalão alkaline dome, were Copebras/CMOC International has operations. The content of P2O5 in the ROM has been reduced over the years and, as a consequence, the content of the contaminants in the concentrate, produced by flotation, which enhances the difficulty in the phosphoric acid production. Only traces of arsenic, iron, and heavy metals can be present in high-purity phosphoric acid. The circulating load of the Copebras’ phosphate rock flotation circuit was submitted to bench scale flotation tests with addition of a milling step were carried out in order to increase the recovery of P2O5 and the reduction of the Fe2O3 content to values below 5%. Samples were collected from the flow composed by the scavenger concentrate and cleaner tail, with d95 <208 >μm and average content of 26.2% of P2O5 and 13% of Fe2O3 (6% hematite, 5% goethite, 1% magnetite, and 1% ilmenite) and comminuted in a pilot pant rod mill. Three samples with different d95 (2O3 content (for the sample with d95 <150 >μm). The industrial implementation of a milling stage of the flotation circulation load and a subsequent flotation of this material has the potential to increase the overall process efficiency by approximately 5.5%, resulting in a production increase of 62,000 tons/year of phosphate rock concentrate, with higher quality than the one currently produced. The phosphate rock flotation tailings feeds a niobium processing plant, a co-product of extreme importance due to its economic value. The proposed circuit increased the niobium liberation degree and its content in the produced tailings, which will probably lead to a higher recovery of the same.

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