Beneficiation of a Sedimentary Phosphate Ore by a Combination of Spiral Gravity and Direct-Reverse Flotation

Abstract

Abstract:In China, direct-reverse flotation is proved to be applicable to most phosphate ores. However, because the ratio of froth product is generally high, current direct-reverse technology faces challenges in terms of high reagent consumptions and cost. A new gravity and flotation combined process has been developed for the recovery of collophanite from sedimentary phosphate ore from the beneficiation plant of Hubei, China. In this process, 53% of the collophanite was firstly recovered by gravity separation, reducing the mass flow to direct flotation. The gravity tailing was the feed for the direct flotation. The flotation concentrate, mixed with gravity concentrate, was then subjected to reverse flotation. A final concentrate with a grade of 30.41% P 2 O 5 at a recovery of 91.5% was produced from the feed analyzing 21.55% P 2 O 5 . Compared to the conventional direct-reverse flotation 86.1% recovery at 31.69% P 2 O 5 , it was found that pre-recovery of collophanite by spiral separation could significantly reduce the flotation reagent consumption and lead to improved overall collophanite recovery. The benefits of the new process in terms of cost savings were also discussed.

Application and Mechanism of Anionic Collector Sodium Dodecyl Sulfate (SDS) in Phosphate Beneficiation

“…The results in Table 3 showed that phosphorus was concentrated in coarse size fractions, which might be related to mineral properties: (1) The particle size of collophane is larger than dolomite and quartz; and (2) Argillaceous fractions are easy to grind. Meanwhile, the density of collophane is slightly greater than dolomite, quartz, and clay [20], so the ore can indeed be concentrated by gravity separation (and, thus, separated by a gravity-flotation combination process). …”

“…The ratio is The K sp values of Mg(DS) 2 and Ca(DS) 2 were obtained as follows [28,29]: Table 3, the average particle size of dolomite was smaller than collophane; the density differences between them is very small [20], so dolomite is more readily entrained than collophane. An entrainment phenomenon was also observed in the SDS reverse flotation tests.…”

“…Owing to the small density differences among the minerals in the raw ore and fine-grained separation feed, a spiral chute (P/D = 0.36) was selected for separation [20,26]; 3 kg of separation feed was processed with a five-turn laboratory spiral chute at a pulp density of 18 wt % solids. Tests were conducted under the condition of 215 L/h feed rate and no wash water.…”

“…The gangue minerals can be roughly divided into two categories: silicate minerals and carbonate minerals [16][17][18]. The direct-reverse flotation process, in which the siliceous minerals are discharged by direct flotation while the calcareous minerals are discharged by reverse flotation, is a popular approach to separation [19,20] but one that comes with several drawbacks, including high reagent consumption, high flotation temperature, and severe environmental pollution. The gravity-flotation combination beneficiation of mid-low grade collophane has been proven effective [21,22], but the high acid consumption of the reverse flotation stage remains problematic [23].…”

Production of a Phosphate Concentrate from the Tailings of a Niobium Ore Concentrator

“…The 1.31 upgrading ratio (the upgrading ratio is the ratio of P 2 O 5 content of the pre-concentrate to the P 2 O 5 content of the feed) obtained with the spiral is comparable to the 1.2 ratio achieved with the hydrocyclone. The idea of testing the spiral is inspired from the work of Liu et al [22] and was motivated by the fact that apatite is slightly denser and coarser (see Table 4) than the carbonates and it was felt that the spiral could yield a better cut than the hydrocyclone. However, the spiral used for the evaluation is designed for processing coarse material (>1000 µm), while the CC is finer than 150 µm.…”