Method of extracting rare-earth metals (rem) from phosphogypsum. RU patent 2492255.

FIELD: metallurgy.

SUBSTANCE: proposed method comprises REM and phosphorus leeching by sulfuric acid solution to obtain leaching solution and insoluble residue. Said insoluble solution is processed by calcium compound to pH over 5. PEM concentrate is extracted from said solution by crystallisation and fed to REM and phosphorus leaching stage. Prior to leaching phosphogypsum is subjected to flushing with water to obtain flushing solution containing REM and phosphorus. Said insoluble residue is flushed before processing by calcium compound. Obtained flushing solution is processed by calcium compound to produce pulp with pH not over that of REM phosphate precipitation beginning and combied with said flushing solution. REM is sorbed by cation exchangers and separated to desorb REM therefrom to produce desorbent and recovered cation exchanger. Said recovered cation exchanger is sent to REM sorption while desorbent is sent to REM concentrate production stage. Phosphorus and associated impurities are deposited from sorption mother pulp. Obtained pulp is separated in residue to be recovered and water phase to be used as circulating water.

EFFECT: higher efficiency lower loses.

12 cl, 1 dwg, 3 ex

The invention relates to the chemical industry, namely to the technologies of phosphogypsum processing.

There is a method of extraction of rare earth metals and yttrium (hereinafter REE) of phosphogypsum are obtained in the sulphuric processing of Apatite concentrate for mineral fertilizers by means of leaching diluted 0,5-1,0%of the time by solutions of sulfuric acid (Lebedev V.N. and others, Removing REE from phosphogypsum leaching methods. // Physical-chemical and technological problems of processing of raw materials of the Kola Peninsula. - St.Petersburg: Nauka, 1993. - P.56-60). Significant disadvantages of this method are high ratio of the liquid and solid phases (W:T=(5-10):1) leaching and correspondingly low (0,25-to 0.37 g/l) REE contents of the pregnant solution at a relatively low ~32-43%extracting them from phosphogypsum.

Also known way extraction of rare-earth of phosphogypsum (EN 2225892, Lokshin and others, 20.03.2004), including sequential leaching them from several servings of phosphogypsum working solution 20-25%sulfuric acid at W:T=2-3 within 60 minutes, the separation of insoluble residue from a productive solution, crystallization concentrate of REM in the form of sulphate by bringing a productive solution to the state of the supersaturated by REM increase of the concentration of acid to & GE; 30% at a temperature of 20-80°N Crystallization of sulphates REM spend preferably in the presence of the seed of them with W:T not more than 100 for 0.4-3 hours Removing the REM in concentrate is within 50-60%, then it is subjected to conversion of obtaining concentrated solutions nitrates or chlorides of rare-earth. Disadvantages of the method consists in the considerable number of technological operations and their increased duration, very high W: So

Know how to extract the REM of phosphogypsum (EN 2167105, Lokshin and others, 20.05.2001), including their portion leaching, Department of mother liquor from the solid phase and its repeated use for leaching new portions of phosphogypsum, water leaching of insoluble residue, using the washing solution leaching. The leaching of REM from the first portion of phosphogypsum produce 2-6%solution of sulfuric acid at W:T=2-3, and for each subsequent portions of phosphogypsum concentration of acids increase under one condition. Solution leaching use at least three times, and the maximum concentration of a sulfuric acid in solution is 24%. Disadvantages of the method are the multistage process of leaching of REM, the need for a sufficiently precise control and maintenance) of the desired conditions, and relatively low removing the REM of phosphogypsum in the solution.

Know how to extract the REM of phosphogypsum (EN 2293781, Lokshin and others, 20.02.2007), according to which phosphogypsum process solution of sulfuric acid with concentration from 22 to 30 wt.% when W:T=1,8-2,2 within 20-30 minutes with extraction of rare earth elements and sodium solution to prevent such duration of the process of spontaneous crystallization concentrate rare earth elements from the leach solution to separate it from the insoluble residue. After the separation of insoluble residue in the solution increases the degree of supersaturation it by REM by ensuring the concentration of sodium in the range 0.4-1.2 g/l, using, mainly, sulfate or sodium carbonate. The disadvantages of this method - a significant loss of REM contained in the wet insoluble residue and during preparation for disposal and accumulation of pollutants in products of the technological process.

Describes how to retrieve REE of phosphogypsum (EN 2416654, NV and others, 20.04.2011), including his washing phosphorus from water carried in a closed cycle with its subsequent disposal by the passing of leaching solution through a layer of carbonate departing and returning (turnover) of the depletion phosphorus water in the washing cycle of phosphogypsum to achieve a pH of the water wash, equal to 2.0. Next phosphogypsum lead leaching REM solutions of sulfuric acid at concentrations from 3 to 250 g/l in mode heap leaching, absorb REM cation exchanger, was stripped them with a solution of ammonium nitrate to produce commodity and return reverse cycle sulfate mother solution sorption.

Disadvantages of this method are very low rate of water filtration at wash phosphogypsum from phosphorus leaching of sulphuric acid solutions through a layer of phosphogypsum equal 0,00036 cm/s (30 cm per day) ( N.V., and others, Recycling of solid waste phosphogypsum. // New approaches in chemical technology and practice of processes of sorption and extraction. Conference materials: Saint-Petersburg, 2011). It causes the () the duration of the specified processes, and in particular heap leaching high (≥ 10) the ratio W:T, loss of REM with the waters washing phosphogypsum from phosphorus, which account for about 3%, which consequently reduces the degree of extraction of rare earth into concentrate, a significant reduction in the efficiency of sorption and desorption REM with the decrease of their concentration in pregnant solution (up to a few milligrams per liter) in the process of leaching.

Closest to the technical nature and the result achieved by method is a method of processing of waste, containing phosphorus and lanthanides (EN 2337879, Lokshin and others, 10.11.2008 - prototype). This method involves leaching of phosphogypsum phosphorus and RCM sulfuric acid solution (in particular, 22-30%-s ' solution of H 2 SO 4 during 20-25 minutes) with a satiated by REM productive leach solution and gypsum sludge, separation of the latter from the leach solution and subsequent processing of the main compound of calcium ( particular, or slaked lime or limestone) to a pH of more than 5, the allocation of a concentrate of REM from the leach solution by crystallization of double-earth metals and sulfates, sodium upon standing sulphate solution within 2 hours, control is obtained when this stock solution crystallization on phosphorus and if the magnitude of the works of the content of phosphorus in the solution and sludge moisture gypsum x·y<180, where x is the content of phosphorus in stock solution in terms of P 2 O 5 , g/l, y - humidity gypsum sludge (%), the direction of the stock solution to the stage of leaching, and when the value of x·y & GE 180, on preliminary cleaning compounds of titanium stock solution of phosphorus.

Disadvantages of the method prototype is a significant (10%) losses REM wet (20%) sediment gypsum, lack of allocation of associated product with a high content of phosphorus, for example, fertilizers, as well as the need for cleaning compounds of titanium stock solution of phosphorus.

The present invention is directed to increase of technical and economic efficiency of phosphogypsum processing and reduction of losses recoverable components.

Method for processing of phosphogypsum includes leaching of REM and phosphorus a solution of sulfuric acid to obtain the leach solution and insoluble residue, insoluble residue processing the main compound of calcium to pH & GE 5, the allocation of a concentrate of REM from the leach solution crystallization, Department of concentrate of REM from mother liquor crystallization, his the feed stage leaching of REM and phosphorus.

Difference method are that the source phosphogypsum subjected to water sludge from phosphorus obtaining leaching solution containing phosphorus and RCM at pH, not higher pH begin precipitation REE phosphates.

Insoluble residue before processing the main compound of calcium subjected to water washing and received wash solution process the main connection with the formation of calcium pulp with a pH, not higher pH begin precipitation REE phosphates and combine with an flush solution of phosphogypsum.

From pulp obtained REM absorb cation exchanger, is separated from the uterine pulp sorption and was stripped of his rare-earth metals with obtaining and regenerated cation exchanger, which refer to the stage of sorption of REM, and - the production of concentrate of REM.

From the fallopian pulp sorption precipitated phosphorus and related impurities by processing the main compound of calcium to a pH equal to or more than 5.5 received the pulp of a share on the cake, which sent for recycling, and the aqueous phase, which is used as cooling water.

The method can characterized by the fact that the aqueous washing phosphogypsum from phosphorus spend in the pulp at W:T=1:1, and its division into the water phase and phosphogypsum and its water flush - if G:R=0,15-0,5 filter mode liquid displacement with getting the washing solution Association of the aqueous phase and washing water.

The method can be characterised by the fact that the leaching of lead 22-30%solution of sulfuric acid at W:T=1,8-2,2, as well as the fact that the leaching of lead during 20-25 minutes

The method can be characterized also by the fact that the water leaching of insoluble residue spend on the filter if G:R=0,15-0,5 mode liquid displacement, and the fact that the wash solution process the main connection with the formation of calcium pulp with a pH of 1.5-2.0.

The method can be characterized, in addition, the fact that in the process of crystallization of a concentrate of REM in the leaching solution sodium concentration is not less than 0.4 g/l, and the fact that, as of cation use KU-2 gel structure or its analogues.

The method can be characterised by the fact that recycled water is used for water washing of phosphogypsum from phosphorus and water flush insoluble residue, as well as the fact that the processing of uterine pulp sorption REM major interconnection calcium lead in air stirring. The precipitate formed when processing the fallopian pulp sorption REM may be sent for recycling of phosphorus. As the primary connection calcium can be used limestone or quicklime or slaked lime, or their mixture.

The technical result is a significant reduction of losses of REM with moisture insoluble residue, no preliminary purification from phosphorus circulating on the stage of leaching stock solution crystallization concentrate of REM, passing into a product with a high content of phosphorus, for example, fertilizers, possibility of utilizing dioxide carbon, as well as rational water circulation scheme.

Schematic diagram of the method is presented on the figure.

The method is as follows. Water washing phosphogypsum from phosphorus is carried out by preparation of pulp when W:T=(0,75-1):1, division into the aqueous phase and phosphogypsum and its water flushing at W:T=0,15-0,50 filter mode liquid displacement or tsentrifugirovaniem with obtaining phosphorus and REM washing solution with pH≤2 Association of the aqueous phase and washing water. The degree of shading phosphogypsum from phosphorus not less than 50%, and residual content of P 2 O 5 in not exceed 0.5%.

Insoluble residue before processing the main compound of calcium subjected to the washing of the water (circulating water) when W:T to be < 0.5 and received wash solution process with the formation of limestone slurry with pH not higher pH begin precipitation of phosphate REM (equal to about 2.3), preferably with a pH of 1.5-2. Emitted when the carbon dioxide can be disposed of, in particular, for the regeneration of soda in case of its use for the conversion concentrate double sulfate of sodium and REM [Na(REM)(SO 4 ) 2 ] in concentrate REE carbonates [(REM) 2 (3 ) 3 ].

Pulp obtained during the processing of leaching solution of insoluble residue, together with an flush solution of phosphogypsum and formed the pulp with pH=1,5-2,0 absorb rare earth metals cation exchange resin, in particular a strong acidic KU-2 gel structure or its equivalent (for example, cation exchanger CU-2-8h).

Separate cation adsorbed REM from the fallopian pulp sorption and was stripped of his REM known method, for example, a solution of mineral salts (NH 4 NO 3 ) obtaining REM and regenerated cation. sent for production of concentrate of REM in a known way, and regenerated cation - on the stage of sorption of REM.

From the fallopian pulp sorption precipitated phosphorus and related admixtures (Fe, Al and others), by processing its major interconnection calcium to pH & GE 5,5. Received the pulp of a share on the cake, which sent for recycling, and the aqueous phase, which is used as cooling water.

Some (e.g., 5-10%) recycled water can be used when disposing of insoluble residue (gypsum) or for other purposes. It allows to increase the output from the process substances (including sodium and phosphorus).

Water rinse, phosphogypsum from phosphorus, in particular on the filter if G:R=0,15-0,50, i.e. in the mode of displacement of phosphorus-containing solution is effective technological operation. As follows from Lokshin .., O.A. Cleaning from impurities when removing the lanthanides. /Scientific bases of chemistry and technology of processing of complex raw material and synthesis on its basis of functional materials. All-Russian scientific conference with international participation. Materials of the scientific-technical conference - Apatity: publishing house of the . 2008. - .130-136), at wash in the displacement mode, at a rate of leaching water 100-150 kg per 1,000 kg of phosphogypsum may reduce the residual content of sulphuric acid and water-soluble phosphorus in 2-2,5 times.

Experiments have shown that the water rinse, phosphogypsum from phosphorus prior to leaching of REM, and the output from the process of the principal amount of phosphorus contained in the leaching solution of insoluble residue, allow to maintain the concentration of phosphorus in the solution of leaching and in circulating breeding solution crystallization concentrate REE not exceed 6-8 g/L. This virtually eliminates significant precipitation of phosphate-earth metals and their losses with an insoluble residue in the process of leaching, and eliminates the need for cleaning the mother liquor crystallization using titanium compounds, providing the required low (<0.5%) of the residual content of P 2 O 5 in insoluble residue (plaster) and its suitability for recycling.

Reductions in the ratio W:T below 1.8 leads to a decrease, and at W:T>2,2 only to a slight increase in the degree of extraction of rare earth from phosphogypsum, and at W:T>2,2 decreases the degree of supersaturation of solution according to the REM and the efficiency of the process of crystallization of them concentrate as a double sulfates.

The optimal duration of leaching REM is 20-25 minutes, because at the time leaching less than 20 minutes is not reached rational degree of dissolution contained in hydrated phosphates and fluorides of rare-earth metals, and at the time leaching over 25 min begins spontaneous crystallization from solution of REM, in particular in the form of their double sulfate of sodium. That is, if the duration of leaching of equal 20-25 min ensures rational degree of extraction of rare earth in the solution of phosphogypsum and almost prevented them a noticeable spontaneous crystallization before the separation of productive solution from the insoluble residue (gypsum). To increase the speed and completeness of crystallization of REM it is advisable to introduce into the solution of the seed in the form of current crystals double sulfate of sodium and REM.

Sorption of REM (in particular, cation exchanger CU-2-8h) to not less than 90% exclude them loss with water insoluble residue (gypsum), which is characterized by a prototype method. Phosphorus precipitation and related admixtures (Fe, Al and others) from the fallopian pulp sorption REM at pH & GE 5,5 preferably carry on with its air mixing with the main compound of calcium. This gives the possibility of allocating precipitated not only the principal amount of phosphorus, ferric iron, alumina, and ferrous iron, which at pH & GE 5,5 to 5.5-5.8) and effectively oxidized by oxygen in the air to the trivalent state and enters into the sediment.

For neutralization of sulfuric acid moisture insoluble residue phosphogypsum and for processing the mother liquor sorption REE as the main compounds of calcium use preferably limestone, hydrated and quicklime or their mixtures, as the most affordable and environmentally friendly chemicals, excluding admission solutions of additional ions.

Patent-pending combination of features of the invention provides for the rational implementation of phosphogypsum processing at improving technical and economic indicators by reducing the loss of REM waste production, reduce the number of used chemical reagents, prevent the accumulation of phosphorus and related impurities in current products, associated receipt of sludge with a high content of phosphorus and carbon dioxide, are suitable for the effective utilization, as well as at the expense of rational water circulation.

Rationale obtain a technical result is illustrated by the following examples.

Example 1. Prepare the pulp during T:G about 1:1 by mixing 1000 g dump phosphogypsum, containing, % Mas.: 0,44 aff(REM), 2 O 3 ; 1,21 P 2 O 5 ; 0,47 Na with 1000 cm3 of water for 10 minutes Then the pulp is filtered, the secrete 650 cm 3 leachate containing in g/l: 8,2 P 2 O 5 and 0,124 aff(REM), 2 O 3 and has a pH sankhobe 1,55. Cake is washed on the filter with water in amount of 250 cm 3 , i.e. with s:l=1:0,25 mode liquid displacement of cake and receive ~250 cm 3 leachate concentration, g/l: about 4,8 P 2 O 5 and 0.08 aff(REM), 2 O 3 and cleaned from phosphorus KEK (phosphogypsum)containing, % Mas.: ~0.4 P 2 O 5 and about 0,43 aff(REM), 2 O 3 with humidity of 25.9%.

Combine mentioned obtaining 895 3 cm washing solution phosphogypsum from phosphorus-containing 0,112 g aff(REM), 2 O 3 and 7.2 g/l P 2 O 5 and has a pH of 1.75.

The degree of shading phosphogypsum from phosphorus is about 53,7%, while the degree of extraction of rare earth in the wash solution is equal to 2.3%.

To from phosphorus add water and concentrated sulfuric acid based education pulp ratio s:l=1:2 and the concentration of ~26% H 2 SO 4 and conduct leaching REM (and phosphorus) with stirring pulp for 20 min at room temperature. The resulting slurry share on the filter for about 5 min on the insoluble residue (gypsum) and leaching solution in the number of 1650 cm 3 with a concentration aff(REM), 2 O 3 , P 2 O 5 , Na and H 2 SO 4 count for approximately 1,55; 1,40 -- for 0.3 and 245.

The degree of extraction of rare earth in the solution of leaching from washed from phosphorus phosphogypsum is 72,1%.

Insoluble residue is washed with water with s:l=1:0,3, its humidity is about 27% at the content in solid phase ~0,12% aff(REM), 2 O 3 and 0.28% P 2 O 5 in terms of air-dry the product and in moisture 0.54 g/l Fn(REM), 2 O 3 and about 0.5 g/l P 2 O 5 .

After water flush insoluble residue mixed with 40 g of finely ground limestone to mitigate residual acidity of the water phase (to pH sankhobe 5,7) and remove it for recycling. This stands approximately 12 grams of carbon dioxide (CO 2 ).

Solution leaching (1650 cm-3 ) is matured during & GE 2 h at bringing the concentration of sodium to approximately 1.2 g/l, with the help of Na 2 SO 4 ·10H 2 O for allocation by the crystallization of sediment (concentrate) double-earth metals and sulfates, sodium. The obtained suspension of crystals Na(REM)(SO 4 ) 2 share filtering mother solution crystallization of about 1650 cm 3 with the content, g/l: 0,16 aff(REM), 2 O 3 ; CA 1,4P 2 O 5 and about 245H 2 SO 4 and concentrate REM containing, % Mas.: 26,8 aff(REM), 2 O 3 ; 0,18 P 2 O 5 ; 7,60 Sa; 0,28 Pe 2 O 3 ; 0,06 Al; 0,42 SiO 2 and 53,9 SO 4 2- .

The degree of extraction of rare earth in concentrate in the process of crystallization is 93.7%.

Mother solution crystallization is used in circulation for leaching REM (and phosphorus), with a circulation of REM is 5-6%.

Wash solution insoluble residue in the amount of 300 cm 3 with the content in it, g/l: 1,17 aff(REM), 2 O 3 ; 1,06P 2 O 5 and about 175H 2 SO 4 process with the formation of limestone slurry with a pH equal to 1.5 (i.e. with a pH of less than the beginning of pH of precipitation of phosphate REM, which is equal to about 2.3) and about 20 grams of carbon dioxide CO2 . The latter may be utilized, for example, for regeneration soda in case of its use for the conversion concentrate double sulfate Na(REM)(SO 4 ) 2 in carbonates (REM) 2 (3 ) 3 .

The resulting slurry with pH sankhobe 1,5 combined with an flush solution of phosphogypsum. From an educated the pulp in the amount of about 1200 cm 3 , containing in g/l: 0,38 aff(REM), 2 O 3 ; 5,6P 2 O 3 and having a pH sankhobe 1,6 absorb REM strong acidic gel structures (KU-2-8h) in the N-form air stirring and room temperature.

From the saturated up to 72 mg/g REE cation exchanger was stripped rare earth metals solution of ammonium nitrate to produce commodity with the content in it ~0,42 g aff(REM), 2 O 3 , which corresponds to ~9,6%of extraction of rare earth from phosphogypsum. The resulting can be redesigned into a marketable product REM known methods (using the operations deposition, ion-exchange sorption, liquid-liquid extraction and others). Uterine pulp (solution) sorption contains ~ 0.008 g/l Fn(REM), 2 O 3 and about 5.7 g/l P 2 O 5 . The degree of sorption extraction of rare-earth is about 97%.

From the fallopian pulp sorption precipitated phosphorus (and accompanying impurities - Fe, F, Al and others), by processing it limestone to pH sankhobe 5,7 air stirring. Air pulp mixing allows pH & GE 5,6 oxidized by oxygen of air divalent iron and highlight it in the sediment. The resulting slurry is filtered and receive KEK - sediment (about 95 grams per air-dry weight) with the content of phosphorus about 6.5% and 1170 3 cm leachate concentration of phosphorus <0.2 g/L.

sludge sent for recycling, for example, for the production of fertilizers, and the filtrate is used as recycled water for making pulp of phosphogypsum and his flashing of phosphorus, as well as for washing insoluble residue (gypsum) from phosphorus. The total removing the REM from the dump of phosphogypsum concentrate in the form of double-earth metals and sulfates, sodium, and in trade REM is about 61.7 percent, and taking into account REM contained in the stock solution crystallization REE - 67,8%.

Example 2. Processing 500 g dump phosphogypsum in example 1. The difference is that after washing of phosphogypsum from phosphorus leaching from him REM lead with s:l=1:1,8 within 25 minutes by mixing it with 650 cm 3 stock solution crystallization concentrate of REM received by example 1, with the adjustment of the concentration of H 2 SO 4 to 22 wt.% using concentrated sulphuric acid.

As a result of degree of extraction of rare earth were as follows: the solution of leaching and 70.2% (with concentration of REM in solution of 1.79 g/l); in concentrate aff REM (double sulfate of sodium and RCM) mass ~4.1 g - 48,1% in the degree of crystallization of REM -90,5%, the rare earth content in concentrate 27.1%; in the mother solution crystallization concentrate REM - 5,05%; in trade REM ~12,6%; in the sediment in the deposition of phosphorus from the fallopian pulp sorption REM ~of 0.4%.

Content in insoluble residue (cast) was ~0,15% aff(REM), 2 O 3 and 0.32% P 2 O 5 . The concentration of P 2 O 5 in stock solution crystallization concentrate of REM ~2,44 g/l Number of selected WITH 2 when processing insoluble residue (gypsum) is approximately 3.5,

The total removing the REM from the dump of phosphogypsum concentrate in the form of double-earth metals and sulfates, sodium, trade REM and in the mother solution crystallization REM - 65,7%.

The total loss of REM are ~34,3%, including with an insoluble residual (gypsum) to 33.9% and sediment, resulting in the deposition of phosphorus from the fallopian pulp sorption REM ~of 0.4%.

Example 3. Processing of 300 g dump phosphogypsum in example 2. The difference is that after washing phosphogypsum from phosphorus leaching REM from wet (about 30 percent) of phosphogypsum are with s:l=1:2 for 25 minutes by mixing it with 420 cm 3 stock solution crystallization concentrate of REM received by example 2 with the adjustment of the concentration of H 2 SO 4 to 30 wt.% using the concentrated sulfuric acid.

The result of this experiment, the degree of extraction of rare earth amounted to: in the leaching solution - 72% (with concentration of REM ~1.67 g/l); in concentrate aff REM (double sulfate of sodium and RCM) weight 2,64 g - 51,3% in the degree of crystallization REM - 91% and the content of REM in concentrate ~27%; in the mother solution crystallization concentrate REE - 5.1% of the total content of rare earths in ; in the commodity REM - 11,9%.

Content in insoluble residue (cast) was ~0,145% aff(REM) 2 On 3 and 0.3% P 2 O 5 . The concentration of P 2 O 5 in stock solution crystallization concentrate REM - 3,21 g/L. the Number of dedicated CO 2 when processing insoluble residue (gypsum) about 10,

Quantity of sediment obtained in the deposition of phosphorus from the fallopian pulp sorption REE - 44 g when the content in it about 5% P 2 O 5 .

The total removing the REM from the dump of phosphogypsum concentrate in the form of double-earth metals and sulfates, sodium, and in trade REM is 63,2%, and taking into account REM contained in the stock solution crystallization REM - 68,3%.

The total loss of REM are ~31,7%, including with an insoluble residual (gypsum) 31.3% and the sediment, resulting in the deposition of phosphorus from the fallopian pulp sorption REE - 0,36%.

It should be noted that the concentration of phosphorus leaching solution will increase for use in the turnover of phosphate mother liquors crystallization of REM until the number of leached phosphorus is equal to its number, from the process and primarily by means of leaching solution phosphogypsum, that can adjust the ratio W:So In relation to the reviewed examples of this is the concentration of phosphorus in terms of P 2 O 5 in the solution leaching within 6-7 g/HP

For comparison, the loss of REM with an insoluble residual (gypsum) during the processing of 1 kg of phosphogypsum with the content of 0.44% of the aff(REM), 2 O 3 according to the examples 1, 2 and 4, steps in .RU 2337879 amounts to 1.7-2.0 g or 33.3-39,2%, 1-7% higher than method.

Removing the REM of phosphogypsum can be further improved by 1.0-1.5% at the increase of the W:T, in the process of water flush insoluble residue (gypsum), from 0.3 to 0.5. The expediency of this is determined taking into account the current value of REM and operating costs.

Thus, as follows from the above examples, patentable method for processing of phosphogypsum can virtually eliminate any significant precipitation REE phosphates in the process of sulfuric acid leaching by pre water washing of phosphogypsum from phosphorus. The method gives opportunity to reduce the loss of REM by water flush insoluble residue (gypsum) and cation-exchange sorption REE of wash water phosphogypsum and insoluble residue to produce commodity REM, and provide a rational water circulation scheme with the cleaning of circulating water of impurities.

The obtained products - insoluble residue (gypsum) with the content of P 2 O 5 <0.5%of the sediment with increased to 5-6% content of P 2 O 5 , and carbon dioxide can be effectively utilized.

1. Method for processing of phosphogypsum, including leaching of rare earth metals (REM) and phosphorus mortar sulfuric acid to obtain the leach solution and insoluble residue, insoluble residue processing compound calcium to a pH of more than 5, the allocation of a concentrate of REM from the leach solution crystallization, Department of concentrate of REM from mother liquor crystallization, feeding on stage leaching of REM and phosphorus, characterized in that prior to leaching source phosphogypsum subjected to water sludge from phosphorus obtaining leaching solution containing phosphorus and REM if the pH is not above the pH of the beginning of the deposition REE phosphates, insoluble residue after leaching before processing connection calcium subjected to water washing received wash solution process connection with the formation of calcium pulp with pH not above the pH of the beginning of the deposition REE phosphates and combine with an flush solution phosphogypsum, from pulp obtained REM absorb cation exchanger, separate it from the fallopian pulp sorption and was stripped of his REM obtaining and regenerated cation exchanger, which refer to the stage of sorption of REM, and - the production of concentrate of REM, from the fallopian pulp sorption precipitated phosphorus and related impurities by processing the connection calcium to a pH equal to or more than 5.5 received the pulp of a share on the cake, which sent for recycling, and the aqueous phase, which is used as cooling water.

2. The method according to claim 1, characterized in that the aqueous washing phosphogypsum from phosphorus spend in the pulp at W:T=1:1, and its division into the water phase and phosphogypsum, its water flush - if G:R=0,15-0,5 filter mode liquid displacement with getting the washing solution Association of the aqueous phase and washing water.

3. The method according to claim 1, characterized in that the leaching of lead 22-30%solution of sulfuric acid at W:T=1,8-2,2.

4. The method according to claim 1, characterized in that the leaching of lead during 20-25 minutes

5. The method according to claim 1, wherein the water leaching of insoluble residue spend on the filter if G:R=0,15-0,5 mode liquid displacement.

6. The method according to claim 1, wherein the wash solution is treated connection with the formation of calcium pulp with a pH of 1.5-2.0.

7. The method according to claim 1, characterized in that in the process of crystallization of concentrate of REM in the leaching solution sodium concentration is not less than 0.4 g/L.

8. The method according to claim 1, characterized in that in the capacity of cation exchanger use KU-2 gel structure or its analogues.

9. The method according to claim 1, wherein the water washing of phosphogypsum from phosphorus and water flush insoluble residue use recycled water.

10. The method according to claim 1, characterized in that the processing of the fallopian pulp sorption REM connection calcium lead in air stirring.

11. The method according to claim 1, characterized in that the sludge formed during the processing of uterine pulp sorption REM connection calcium, sent for recycling of phosphorus.

12. The method according to claim 1, characterized in that the compounds of calcium use limestone or quicklime or slaked lime, or their mixture.