A review of the beneficiation of calcareous phosphate ores using organic acid leaching

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Double reverse flotation process of collophanite and regulating froth action

Uranium in sediments, mussels (Mytilus sp.) and seawater of the Krka river estuary.

The Late Cretaceous (Campanian-Maastrichian), low-grade phosphorite sequence of East Sibaiya, Aswan area, which is known as the Duwi (phosphate) or Sibaiya Formation, is usually intercalated with marl, oyster limestone, and chert beds. These strata, which crop out in a generally east–west trending belt spanning the middle latitudes of Egypt, are phosphorite-rich sediments and of great economic importance. Representative samples were collected from the investigated area at several localities (e.g., Umm Tundubah-2 and Wadi El-Batur) and 200 kg of phosphate rocks was used for upgrading processes of low-grade phosphorites of the East Sibaiya area. The upgrading processes included two techniques: the first technique (gravity separation) comprises crushing, sieving, gravity separation by a shaking table, and magnetic separation. This technique raised the P2O5 in the head sample from 24.73 to 31.91% as a phosphate concentrate. The second technique (flotation technique) depends on certain flotation parameters such as pH, grain size, and phosphate collector dose (i.e., oleic acid). The flotation technique increased the P2O5% from 24.73 to 31.16% as a final product of the phosphate concentrate. These data were confirmed by X-ray fluorescence analyses of major elements.

Proposed upgrading techniques for East Sibaiya phosphorites, Aswan area, southern Egypt

In the phosphate industry, the use of certain flotation reagents can cause severe water pollution and have a negative effect on the environment and human health. Therefore, the development and utilization of eco-friendly flotation reagents are essential for the sustainable production of phosphate ores and phosphate fertilizers. In this work, an economical and environmentally friendly mixed collector based on soybean and sunflower oils soaps was used to improve the grade and recovery of phosphate flotation. The results obtained from the flotation showed that the best composition of the mixed collector was 1:1 of the mass ratio of soybean and sunflower oils. In addition, the results showed that a low collector mass, medium solid content combined with an acidic medium resulted in a better relative floatability. Multi-response optimization was applied to optimize the process variables for both responses simultaneously using the Face Central Composite Design (FCCD). The effect of three independent variables such pH, collector mass, and solid content on the % P2O5 grade, and % recovery was studied. The results revealed that pH and collector mass had the most significant effect of the % grade response, while collector mass had a significant effect only on % recovery. It was found that more than 29.57% for grade content and 98.82% for the recovery can be achieved at the optimum conditions of low pH (pH 4) and low collector mass (0.13 g) and solid content (17.97 wt%). X-ray diffraction of the resulting solids confirms that the phosphate phase remains in the sink and that the gangue flows into the floated part. 

Grade-recovery beneficing and optimization of the froth flotation process of a mid-low phosphate ore using a mixed soybean and sunflower oil as a collector

Four big head phosphate samples (about 200 kg) were collected from West Sibaiya mines [medium grade (sample 1, southern mine), high grade (sample 2, the mine in the cultivated area), low grade (sample 3, oversize), and tailings (sample 4) phosphate ores]. The representative samples were analyzed chemically for P2O5, Fe2O3, Al2O3, InR, CaO, MgO, TiO, MnO, SO42−, F−, Cl− loss on ignition (LOI), and U before and after screen analysis (−10.0 +9.50, −9.50 +6.70, −6.70 +2.0, −2.0 +1.0, −1.0 +0.85, 0.85 +0.710, −0.710 +0.500, −0.500 +0.350, −0.350 +0.250, −0.250 + 0.180, −0.180 +0.125, −0.125 +0.075, and −0.075-mm-size fractions). The different grades of phosphate ores (organogenic-granular phosphorite ores with carbonates, calcite, calcedony, etc.) were beneficiated using local crude rice bran oil and imported oleic acid (individuals) as collectors, NaOH or KOH as the pH adjustor, and Na2SiO3 as the silica depressant. The results indicate that −0.355, +0.180 mm grain size, pH=9.6, 20 minutes conditioning time, 0.7 kg Na2SiO3 (depressant)dose/ton feed ore, 4.25 kg rice bran oil dose/ton feed of phosphate ore or 3.4 kg oleic acid (collector) dose/ton feed of phosphate ore, and cleaning (reflotation) of phosphate concentrates are the optimum conditions for beneficiation of Sibaiya phosphate ores. On cleaning (reflotation) the phosphate ore feeds of samples 1 (medium, P2O5=28.67 pct), 2 (high, P2O5=31.70 pct), 3 (oversize, P2O5=25.30 pct), and 4 (tailings, P2O5=22.61 pct)using rice bran oil as a collector, the feeds beneficiate into concentrates of P2O5 pct equal to 31.87, 34.70, 26.16, and 31.90 pct (recoveries equal 49.41, 61.41, 52.01, and 29.03 pct P2O5) for samples 1, 2, 3, and 4, respectively. On using oleic acid as a collector, P2O5 pct in phosphate feeds of samples 1, 2, 3, and 4 increases (upgrades) into 31.28, 33.95, 26.82, and 30.70 pct in concentrates (recoveries equal 61.74, 53.60, 53.31, and 36.30 P2O5). Comparing the results obtained on using rice bran oil and oleic acid as collectors from the economic point of view, the costs of producing 1 ton phosphate concentrate by rice bran oil are lower (∼LE 70) than those on using oleic acid (∼LE 100) as a flotation collector.

A. E. Mohamed

Papers

Beneficiation of west sibaiya phosphate ores by flotation in alkaline media