By flotation enriched phosphate ore the largest deposits of such, how Kingisepp, Moscow mining and chemical combine (waste sinks), polianskii and shchigrovsky phosphates.

Using anionic, anionic-cationic and cationic flotation.

In the USA for the flotation of phosphate rock currently applied such anionic reagents, as oleic acid and unsaturated fatty acids from vegetable and animal fats, then crude tall oil. It is advisable to use with oleic acid, transformer oil, kerosene, improving the flocculation of phosphate.

When the processing of low-grade phosphate rock Life for flotation was used sulfonated vegetable and lubricating oils, fatty acids and diesel fuel.

Flotation of phosphate ores Africa use tall oil in a mixture with gas oil and fuel oil.

Abroad the patents on reagents for flotation of phosphate rock, representing different combinations of fatty acids and apolar hydrocarbons, alkylarylsulfonates, esters, alcohols and other surfactants, the production of which has increased dramatically in recent years [46].

For flotation of phosphate-factories commonly used crude tall oil (Trastol, Actinоl With), purified tall oil (Actinоl D), sometimes red oil (a mixture of oleic and linoleic acid) or Turkish red oil (sulfonated castor oil). Chemical industry USA manufactured reagents 1, 2, 3 sonneborn, representing neftenaliva, used for flotation of phosphates, and reagents series 800 (801 and 825) – a mixture of naphthenic sulfonic acids. Company Cyan-Amide produced reagents series 700, 765 – refined fatty acids of vegetable origin (linoleic and oleic) with low content of resin acids, 710 – sodium soap of crude fatty acids, in addition to containing oleic and linoleic acids resin acids.

Continuously and in large volume works, directed to the development of highly efficient collectors and their combinations:

§ using dvuhosnovnyj acids alifaticescoe structure (With₃₆), allowing to obtain high-quality phosphate concentrate;

§ the introduction of an additional collector to tall oil di alkylsulfonyl acid, performwhat, aromatic sulfonic acids, monoether sulfonterol acid, etc.

Used and pre-processing ore before the introduction of anionic collectors with a mixture of apolar and sulfonated aromatic hydrocarbons.

Recently fatty acid collector replace synthetic reagents – esters of polycarboxylic acids, sulfonterol acid derivatives, the sulfonates. More effective is the application of polyacrylamide polymer, containing functional group^– and COOH^–, Cathala, atilirovanie amino acids, afrocelt (EPA).

In the CIS are working on the use of products and waste neftesintez, that will expand the range of flotation reagents at no additional cost raw materials, as well as freeing up a large amount of food (plant and animal) fat, used for technical purposes.

The most commonly used fatty acids and their Soaps: tall oil, synthetic carboxylic acids of soft and liquid paraffin, distillation residues alcohols, and acids, distillation residues of synthetic fatty acids and higher fatty acids, oxidized recycl, etc., as well as kerosene, diesel, oil, peat resin. Promising are high-molecular acid, allocated from the bottoms of synthetic fatty acids.

Limiting fatty acids are more selective, than unsaturated. Soap solutions limit acid form in acidic medium coarse flocculi, comprising, apparently, of free acid and acid soap micelles, what are low flotation activity of collectors and its increased consumption. Observed deviation from additivity of the action of reagents, if you apply the main collector in combination with alkylarylsulfonate DS-RAS. In case of equality of total consumption of both reagents and equal technological effect of the specific consumption of the more expensive collector is reduced in 3 times. The effectiveness of the tested combinations of reagents due to the dispersion of the main collector, selective adsorption of the DS-RAS at the interface liquid – gas, and partly its adsorption on the mineral surface with an equivalent reduction in the sodium silicate, sometimes in combination with soda.

Also used monetary alkyl (the alkenyl) succinic acids and Monohydric aliphatic alcohols.

Carboxyl flotation collectors are often done in alkaline medium with the addition of soda, less of sodium hydroxide. When loading in the mill soda reduces activation of minerals by iron oxides. As the primary depressor of gangue minerals (silicates and oxides) used sodium silicate, sometimes in combination with soda.

Abroad for direct flotation of a silicate emulsion amine used in the fuel oil, alkyl-substituted phenyl ether amines, the condensates of N-AMINOETHYLPIPERAZINE, etc. For phosphate flotation using cationic reagents. In Russia of cationic collectors used THEM-11, ANP-14, Armak-12D for extracting froth small amounts of quartz, oxides, silicates. In some cases, to reduce losses of useful mineral with a foaming product used organic depressors [46].

For low quality phosphate ores of Florida developed a scheme, allowing in one stage, method cationic flotation, to obtain a concentrate containing 31,7 % P₂In₅ when removing 84 %. The consumption of the cationic collector, supplied in the form of an emulsion in diesel oil, amounted to 400 g/t [46].

Flotation of phosphate ores, in which the phosphate substance presents fine minerals, proceeds less successfully, than well recrystallizing Apatite. Good for them adding ethoxylated alkylphenol (OP-4), apolar reagents.

Installed, when froth flotation for well washed and obessilennaya ore flotation fatty acids is not difficult, good flotation results can also be achieved in a fairly wide range of pH (8-10).

The main difficulties in flotation of phosphate ores are linked with the presence of finely disseminated dolomite, calcite and especially soluble compounds (gypsum, etc.), and in violation of the selectivity of the process slimes.

Flotation of phosphate ores with a particle size of from 1,2 to 0,08 mm proposed method of enrichment, which is, that first ore is subjected to flotation with cationic reagents, when you remove the froth thinner quartz 0,9 mm. In the second stage of enrichment roughing concentrate cation operation step the efuent is oated with an anionic reagent. During this operation deletes a product in the chamber the larger particles of quartz. The tails are subjected to anionic flotation control flotation. With this in mind the main and control cationic flotation is provided by two-stage desliming in hydrocyclones and Hydroseparators. Prior to anionic flotation is the dewatering in hydrocyclones. From ore, containing 12 % P₂In₅, the result is a concentrate containing 35 % P₂In₅ when removing 95-96 %, tails – of a fineness of 0.5–1 % P₂In₅.

The selection of fine slimes, and separate flotation of Sands and thin provides for classes in the enrichment and Majuscule Kingisepp phosphorite deposits. Sludge (after flotation, with or without) join the concentrate. Froth is removed the quartz, feldspar, glauconite, slate. The quality of the concentrate depends on the amount contained in the ore calcite, which remains together with phosphate in the product chamber. In reverse flotation of phosphate rock and shell collector of the NGA-14 without desliming received several more of the extract. While there was a significant effect of water composition on flotation, cationic collector, as well as the pollution concentrate large quartz. The addition of starch improves the extraction of quartz in froth.

Beneficiation of phosphate rock, containing gypsum, complicated by the fact, he, dissolving, sludge coagulates, and they stick to granular particles. Soda and liquid glass, binding of calcium, do not provide sufficient selectivity, since ions are SO coagulated sludge. Selective flotation of ores of this type fails to increase after processing, the crushed ore 1-2 % solution of sodium chloride and removal of the liquid phase [46].

The most difficult is the enrichment of carbonate-phosphate ores [18]. The separation of phosphate substances and carbonates is possible in two ways:

§ a fatty acid collector flotation of carbonates in the acidic environment (pH = 4,8–5) for depression of the phosphate mixture of liquid glass with salts of polyvalent metals, the sodium HUMATE, molybdate amonium., phosphoric, diphosphorous, sulfuric, silicic fluorine hydrogen acid;

§ the flotation of phosphate in alkaline medium (pH 8-9,5), usually created by soda, a mixture of reagents in a polar carboxyl group, and reagents with sulfo- and phosphate groups.

Flotation metamorphosed, clairaudience ores useful Appendix OP-4. Liquid glass is the low cost to activate the flotation of phosphate, suppressing the flotation of other minerals (especially in the presence of sulfite-alcohol stillage).

For bounded, tempered dolomite-phosphorite ores proposed 2 option of selective flotation: sequential selective flotation of carbonates and phosphate and collective flotation of phosphate and carbonate, and then selective flotation of carbonates. Flotation separation of dolomite and phosphate are based on the best fluoroapatite fatty acid carbonate collector, especially in a weakly acidic environment (pH = 4.5 to 5.0), generated phosphoric acid. So, for bounded, tempered dolomite-phosphorite ores Chulaktau best indicators of enrichment gave the scheme, which provides flotation of carbonates liquid soap (2 kg/t) in the presence of phosphoric acid (7 kg/t), desliming of the product chamber with the direction of slimes in the phosphate concentrate and then flotation of a phosphate with liquid soap (20 g/t) and kerosene (0,75 kg/t) in the presence of soda (1 kg/t) and liquid glass (1 kg/t). From ore 23 % P₂In₅ and 4 % MDO received a concentrate with 29 % P₂In₅ and 1,4 % MDO when removing R₂In₅ more 90 %. Part of the phosphoric acid may be replaced by sulfuric acid. V. I. Tsutsulkovsky installed, that phosphoric acid can be completely replaced H₂SiF₆ when the cost is twice smaller.

A similar method for the enrichment of low-grade phosphate rock karbonizirovannogo Western Mountain States developed by the U.S. Bureau. The flotation circuit includes ottirku ore 12,5 mm in the scrubber at a solids content of 60-65 %, the grinding in a rod mill, desliming class 10 μm and sequential selective flotation of carbonates anionic collector with the depressor H₂SiF₆, and then silicate cationic collector. Chamber the product is cationic flotation contained 30 % P₂In₅ when removing 75%.

Chinese experts for sedimentary phosphorite Hubelj used reagent VO, selectively depressurise and carbonates, and silicates. The ore is ground to a particle size 95 % class -0,074 mm. Then the pulp at a temperature of 40-45 °C was kontaktirovat with reagents (Na₂CO₃ – 4–5kg/t, ЅВ0Ѕ–1–1,5 kg/t and talovym soap – 0,25– 0,32 kg/t) and flotarobolis. As a result of ore 15 % P₂In₅, 5-6 % MgO, 29-33 % SiO₂ the result is a concentrate containing 30-32 % P₂In₅, 2-2,3 % MDO and 12,5 % SiO₂ when removing R₂In₅ 81,5-86,5 %.

Roasting

This method is used for carbonate ores with low content of oxides and semi-silica. These compounds after interaction with oxide of calcium to form low-melting substances (aluminates, ferrites, etc.), enveloping film annealed pieces of ore and preventing absorption.

Although this is a costly process, for some fields it is quite applicable. For example, phosphates, containing large amounts of carbonates and thin impregnation of a phosphate of a substance, conventional methods enriched bad, and roasting, followed by quenching with water and separation of lime gives good performance.

When using this method results in the dismemberment of phosphate units to the size of monomineralic grains without fine grinding.

Dolomite and calcite during firing decompose releasing carbon dioxide and obtaining lime (CaO) and periclase (MgO), after quenching with water moving in the hydroxide CA(IT)₂ and Mg(OH)_2.

Due to thermal decomposition of percarbonate upon firing forms a fluorapatite with a high content of phosphorus in phosphate substance. This increases the maximum possible content of R₂In₅ in concentrate.

The amount of water, add in the quench annealed product, distinguish between "dry" and "wet" extinguishing. In the first case served the minimum possible, nearly stoichiometric required amount of water, allowing to obtain calcium hydroxide in a dry powder, removed by means of dry classification. In the second case, the quenching is performed with excess of water and the suspension. This option gives greater technological effect, but it is associated with the emerging problem of storage and disposal of large quantities of wet particulate sludge. It contains significant amount of phosphorus enriched particles, which extraction is very difficult.

There are various the ways to improve efficiency beneficiation of phosphate ores of the carbonate under the scheme roasting – quenching – desliming. Some of those ways.

It is useful to perform quenching the fired product with water, heated to the boiling point. May also be annealed for 1 h at 1000°C ore cool and wet quenching in an aqueous solution of ammonium chloride, that sharply reduces losses of phosphorus. The resulting ammonia can be removed by distillation and converted into ammonium chloride for re-use. Use of ammonium chloride is added to the sludge, separated from phosphate. Additional benefits can be gained by extraction from a solution of ammonium chloride to pure magnesium hydroxide by treatment of this solution with ammonia, after which magnesium hydroxide precipitates.

Of interest is patented in England a method of increasing the extraction of phosphorus, consisting in the careful transmission of carbon dioxide through the suspension, obtained after quenching with maintaining pH of about 12,5. The result is a complete transformation of calcium hydroxide into calcium carbonate (the end of this reaction corresponds to a sharp drop in pH to 8). Micronized calcite efficiently removed by desliming.