Method of extracting rare-earth metals (rem) from phosphogypsum

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, in particular to the processing of phosphogypsum.

The method for extracting rare earth metals and yttrium (hereinafter REM) of phosphogypsum produced when sulfuric acid processing of Apatite concentrate on mineral fertilizers by leaching dilute 0.5 to 1.0%-governmental solutions of sulfuric acid (Lebedev V.N. and others, Extracting rare earth elements 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 the high proportion of liquid and solid phases (F:T=(5-10):1) leaching and correspondingly low (from 0.25 to 0.37 g/l) content of REE in productive solution at relatively low ~32-43%removing them from phosphogypsum.

There is also known a method of extraction of REE from phosphogypsum (EN 2225892, Church and others, 20.03.2004), including sequential leaching them from several portions of phosphogypsum working solution 20-25%sulfuric acid at W:T=2-3 for 60 minutes, separating the insoluble residue from productive solution, crystallization of REE concentrate in the form of sulphates by bringing productive solution to a supersaturated state in REM increasing the acid concentration to ≥30% at a temperature of 20-80°C. Crystallis the tion of sulfate REM carried out preferably in the presence of the seed of them at W:T not more than 100 for 0.4-3 hours Extraction of rare-earth metals in the concentrate is in the range of 50-60%, then it is subjected to conversion to obtain concentrated solutions of nitrates or chlorides of rare-earth metals. The disadvantages of the method are a significant number of technological operations and their increased duration, very high ratio W: T.

The method for extracting rare-earth metals from phosphogypsum (EN 2167105, Church and others, 20.05.2001), including portions leaching, separation of mother liquor from the solid phase and its reuse for leaching of new portions of phosphogypsum, water wash the insoluble residue with the use of the leaching solution during leaching. While leaching of REE from the first portion of the phosphogypsum produced 2-6%solution of sulfuric acid at W:T=2-3, and for each subsequent portion of phosphogypsum concentration of acid increases on the condition. The leaching solution is used at least three times, and the maximum concentration of sulfuric acid in the leaching solution is 24%. The disadvantages of the method are the multistage process of leaching of REE, the need is clear to control and regulate (maintain) the desired conditions, and relatively low extraction of REE from phosphogypsum in solution.

The method for extracting rare-earth metals from phosphogypsum (EN 2293781, Church and others, 20.02.2007), according to the who phosphogypsum is treated with a solution of sulfuric acid with a concentration of 22-30 wt.% if F:T=1.8 to 2.2 V for 20-30 minutes extraction of rare earth elements and sodium in solution, preventing with such duration of the process of spontaneous crystallization of the concentrate of rare earth elements from leaching solution prior to separation from the insoluble residue. After separation of the insoluble residue in the solution increases the degree of supersaturation him in REM by providing the concentration of sodium in the range of 0.4-1.2 g/l with assistance, mainly sulfate or sodium carbonate. The disadvantages of this method is the significant loss of rare-earth metals contained in the wet insoluble residue and preparing it for disposal and accumulation of impurities in the products of the process.

The described method of extraction of REE from phosphogypsum (EN 2416654, SOC NV and others, 20.04.2011), including its hillshade from phosphorus water carried out in a closed loop with its subsequent utilization by passing a washing solution through the layer of carbonate of departure and return (turnover) depleted in phosphorus water in the washing cycle of phosphogypsum until the pH of wash water, equal to 2.0. Next phosphogypsum lead leaching of REE solutions of sulfuric acid at a concentration from 3 to 250 g/l mode heap leaching, absorb REE cation exchange resin, was stripped of their solution of ammonium nitrate to obtain commercial decorate and return in reverse the cycle sulfate mother liquor sorption.

The disadvantages of this method are very low filtration rate of water at wash phosphogypsum from phosphorus, as well as leaching of sulphuric acid solutions through the layer of phosphogypsum equal 0,00036 cm/s (~30 cm / day) (SOC NV, and others, the Recycling of solid waste phosphogypsum. // New approaches in chemical engineering practice and processes of sorption and extraction. Materials of the conference: St. Petersburg, 2011). This causes a large (multi-day), the duration of these processes and, in particular, heap leaching, and high (≥10) ratio W:T, loss of REM with water washing phosphogypsum from phosphorus, which account for about 3%, which correspondingly reduces the degree of extraction of rare-earth metals in concentrate, a significant reduction in the efficiency of the sorption and desorption of REM with the decrease of their concentration in the pregnant solution (up to several milligrams per liter) in the leaching process.

The closest in technical essence and the achieved result to the patented method is a method of processing of phosphogypsum containing phosphorus compounds and lanthanide (EN 2337879, Church and others, 10.11.2008 - prototype). This method comprises leaching from phosphogypsum phosphorus and REM sulfate solution (in particular, 22-30%solution of H2SO4within 20-25 minutes) to obtain supersaturated in REM productive solution is selecive and precipitate gypsum, the separation of the latter from the leaching solution and the subsequent processing of the basic calcium compound (in particular, slaked or unslaked lime or limestone) to a pH of more than 5, the selection of REM concentrate from the leaching solution by crystallization of the double sulphates of REM and sodium while keeping sulfuric acid solution for 2 h, the control resulting mother liquor of crystallization on the phosphorus content and the value of the works of the content of phosphorus in solution and sludge moisture gypsum x·y<180, where x is the content of phosphorus in the mother solution in terms of P2O5, g/l, y - humidity precipitation of gypsum (%), the direction of the mother liquor on stage leaching, and when the value x·y≥180, pre-treatment of the titanium compounds stock solution of phosphorus.

The disadvantages of the prototype method are significant (not less than 10%) loss of REM wet (20%) with deposits of gypsum, the absence of associated extraction of product with a high content of phosphorus, for example, to obtain fertilizer, as well as the need for treatment of the titanium compounds stock solution of phosphorus.

The present invention is aimed at improving the technical and economic effectiveness of phosphogypsum processing and reduction of losses recoverable components.

The method of phosphogypsum processing includes leaching of P Is M and phosphorus acid with getting the leaching solution and the insoluble residue, the processing of the insoluble residue basic calcium compound to a pH≥5, the selection of REM concentrate from the leaching solution by crystallization, separation of REE concentrate from the mother liquor of crystallization, the addition stage leaching of REE and phosphorus.

Differences method consist in the fact that the original phosphogypsum is subjected to water washing of phosphorus with the receipt of the leaching solution containing phosphorus and REM when pH is above pH to begin precipitation of REE phosphates.

The insoluble residue before processing the basic calcium compound is subjected to water washing and the resulting leaching solution is treated with a basic calcium compound to form a slurry with a pH not higher pH the beginning of the deposition of REE phosphates and unite with proryvnym solution of phosphogypsum.

From the obtained slurry REM absorb cation exchange resin is separated from the uterine pulp sorption and was stripped of his rare-earth metals with getting decorate and regenerated cation exchanger which is sent to the stage sorption of REE and desorbed - to receive REM concentrate.

From the mother of the pulp sorption precipitated phosphorus and related impurities by treatment with a basic calcium compound to a pH of equal to or more than 5.5, the resulting slurry is separated into a residue, which is sent for recycling, and the aqueous phase, which is used as oborot the th water.

The method can be characterized by the fact that water washing phosphogypsum from phosphorus is carried out in the pulp when W:T=1:1, and the division into the aqueous phase and phosphogypsum and water washing - by W:T=0,15-0,5 on the filter mode liquid displacement with getting the leaching solution by combining the aqueous phase and wash water.

The method can be characterized by the fact that the leaching of lead 22-30%solution of sulfuric acid at W:T=1.8-to 2.2, and the fact that leaching of lead within 20-25 minutes

The method can be characterized also by the fact that water washing the insoluble residue is performed on the filter with W:T=0,15-0,5-mode liquid displacement, and the fact that the washing liquor is treated with a basic calcium compound to form a slurry with a pH of 1.5-2.0.

The method can be characterized, moreover, by the fact that in the process of crystallization of REE concentrate in solution leaching the sodium concentration is not less than 0.4 g/l, and the fact that as a cation exchanger, use of strongly acidic sulfonation KU-2 gel structure or its analogs.

The method can be characterized and the fact that the circulating water is used for water washing of phosphogypsum from phosphorus and water washing of the insoluble residue, and the fact that the treatment of uterine pulp sorption of REE basic calcium compound is conducted at an air stirring. Sediment, obrazovan the th when processing uterine pulp sorption of REE, can be sent for recycling of phosphorus. As the basic compound of calcium can be used limestone or quicklime or slaked lime, or a mixture thereof.

The technical result is a substantial reduction in loss of REM with moisture insoluble residue, excluding operations from pre-treatment phosphorus circulating on stage leach mother liquor of crystallization of REE concentrate, associated the product with a high content of phosphorus, for example, to obtain fertilizers, disposal of carbon dioxide, as well as the rational cycle.

Schematic diagram of the method presented in the figure.

The method is as follows. Water washing of phosphogypsum from phosphorus is carried out by cooking the slurry at W:T=(0.75 to 1):1, separation of the aqueous phase and phosphogypsum and water flushing at W:T=0,15-0,50 on the filter mode liquid displacement or by centrifugation with a receipt containing phosphorus and REE leaching solution with a pH≤2 combining the aqueous phase and wash water. The degree of washing of phosphogypsum from the phosphor is not less than 50%, and the residual content of P2O5in phosphogypsum not exceed 0.5%.

The insoluble residue before processing the basic calcium compound is subjected to washing with water (circulating water) when W:T≤0, and the resulting leaching solution is treated with limestone to form a slurry with a pH no higher than the pH of the beginning of the deposition of REE phosphates (equal to about 2.3), preferably at pH of 1.5-2. Produced in this carbon dioxide can be recycled, in particular for the regeneration of soda in the case of its use for the conversion of the concentrate of the double sulphates of sodium and REM [Na(REM)(SO4)2] concentrate carbonates REM [(REM)2(CO3)3].

The pulp obtained by treatment of the leaching solution insoluble residue, together with proryvnym solution of phosphogypsum and formed from this slurry with a pH=1.5 to 2.0 absorb rare earth metal cation, in particular a strongly acidic sulfonic cation exchanger KU-2 gel structure or its analogue (e.g., cation exchange resin KU-2-8h).

Separate the cation adsorbed REE from uterine pulp sorption and desorbed from it REM a known manner, for example, a solution of mineral salts (NH4NO3) to produce decorate REM and the regenerated cation exchange resin. Desorbed is directed to the production of REM concentrate in a known manner, and the regenerated cation - stage sorption of REE.

From the mother of the pulp sorption precipitated phosphorus and related impurities (Fe, Al, and others) by processing its basic calcium compound to a pH≥5,5. Resulting slurry is separated into a residue, which is sent for recycling, and the aqueous phase, which is used as recycled water.

Some (e.g., 5-10%) turnover the ow of water can be used in the disposal of the insoluble residue (gypsum) or for other purposes. This allows to increase the degree of output from the process for the circulating impurities (including sodium and phosphorus).

Water washing of phosphogypsum from phosphorus, in particular on the filter with W:T=0,15-0,50, i.e. in the mode of displacement of phosphate solution, is an efficient process operation. As follows from the work of the Church APP, Tarawa O.A. Cleaning postopera from impurities in the extraction of lanthanides. // Scientific principles of chemistry and technology of processing of complex raw materials and synthesis based functional materials. All-Russian scientific conference with international participation. Materials of the scientific-technical conference - Apatity: publishing house of CNCAN. 2008. - S-136), at wash mode displacement, at a flow rate of wash water 100-150 kg per 1000 kg of phosphogypsum, it is possible to reduce the residual content of sulphuric acid and water-soluble phosphorus in 2-2,5 times.

Experiments have shown that water washing phosphogypsum from phosphorus before leaching REM, and the output from the process main quantity of phosphorus contained in the washing solution of the insoluble residue, allow to maintain the concentration of phosphorus in solution leaching and circulating in the mother solution, crystallization of REE concentrate not exceed 6-8 g/L. This virtually eliminates significant precipitation of REE phosphates and their losses with n is soluble residue in the leaching process, and eliminates the need for purification of the mother liquor of crystallization using titanium compounds, providing the desired low (<0.5 percent) to a residual content of P2O5in the insoluble residue (gypsum) and its suitability for recycling.

The decrease of the ratio of W:T below 1.8 leads to a signicant reduction, and if W:T>2,2 only to a slight increase in the degree of extraction of REE from phosphogypsum, with W:T>2,2 decreases the degree of supersaturation of the solution in REM and the efficiency of the crystallization process them concentrate in the form of double sulphates.

The optimal duration of leaching of REE is 20-25 minutes, because at the time leaching less than 20 min is not achieved rational degree of dissolution contained in the phosphogypsum hydrated phosphates and fluorides of rare-earth metals, and at the time of leaching over 25 min - begins spontaneous crystallization from a solution of rare-earth metals, in particular in the form of a double sulfate with sodium. That is, when the duration of leaching is 20-25 min provided the rational degree of extraction of REE into solution from phosphogypsum and almost prevented them any appreciable spontaneous crystallization separation productive leach solution from the insoluble residue (gypsum). To improve the speed and completeness of crystallization of REE suitable centuries the Denia in the priming solution in the form of working crystals of the double sulphates of sodium and REM.

The selection of REM concentrate of solution leaching (after separation from the insoluble residue) produced by crystallization when the extract solution is not less than 2 h and ensuring the concentration of sodium in the range of 0.4-2 g/L. If necessary, adjusting the concentration of sodium to the desired value using water-soluble salts of sodium, preferably sodium sulfate.

Sorption of REE from protraction (in particular, cation exchange resin KU-2-8h) allows not less than 90% exclude their losses with moisture insoluble residue (gypsum), which is characterized by the prototype method. Phosphorus precipitation and related impurities (Fe, Al, and others) from the mother of the pulp REE sorption at pH≥5.5 to preferably conduct when the air mixing with the basic calcium compound. This gives the possibility of separating precipitated not only the principal amount of phosphorus, trivalent iron, aluminum, and ferrous iron, which at pH≥5,5 (5,5-5,8) effectively oxidized by atmospheric oxygen to the trivalent state and goes into the sediment.

To neutralize the sulfuric acid in the moisture insoluble residue of phosphogypsum and for processing of the mother liquor sorption of REE as basic calcium compounds are used preferably limestone, hydrated and quicklime, or a mixture thereof, as the most accessible and Ekol the same chemical reagents, exclusive admission to the solutions of additional ions.

Patent-pending set of features of the invention provides an efficient implementation of phosphogypsum processing with increasing technical and economic performance by reducing losses REM waste production, reduce the number of chemicals that prevent the accumulation of phosphorus and related impurities in the circulating products, associated receiving sludge with a high content of phosphorus and carbon dioxide, suitable for effective utilization, and also due to the efficient water circulation.

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

Example 1. Prepare the slurry at T:W≈1:1 by mixing 1000 g of waste phosphogypsum containing, % wt.: 0,44 ∑(REM)2O3; 1,21; P2O5; 0,47 Na 1000 cm3water for 10 minutes and Then the slurry is filtered, thus allocate 650 cm3the filtrate, containing g/l: 8,2 P2O5and 0,124 ∑(REM)2O3and having a pH≈1.55V. The cake is washed on the filter with water in the amount of 250 cm3i.e. if T:W=1:0,25-mode liquid displacement from the cake and get ~250 cm3the leachate concentration, g/l: ~4,8 P2O5and 0.08 ∑(REM)2O3and washed from the phosphorus KEK (phosphogypsum), containing, % wt.: ~0,4 P2O5and ~0,4 ∑(REM) 2O3with a moisture content of 25.9%.

Combine the above filtrates with getting 895 cm3the leaching solution phosphogypsum from phosphorus containing 0,112 g ∑(REM)2O3and 7.2 g/l P2O5and having a pH of 1.75.

The degree of washing of the phosphogypsum from phosphorus is ~53,7%, while the degree of extraction of rare-earth metals in the leaching solution is 2.3%.

To washed from the phosphorus phosphogypsum add water and concentrated sulfuric acid based education slurry with a ratio of T:W=1:2 and a concentration of ~26% H2SO4and conduct leaching of REE (and phosphorus) while stirring the slurry for 20 min at room temperature. The resulting slurry is separated into the filter for about 5 min, the insoluble residue (gypsum) and the leaching solution in the amount of 1650 cm3with a concentration of ∑(REM)2O3P2O5, Na and H2SO4accordingly ~1.55V; 1,40; ~0.3 and 245.

The degree of extraction of REE into solution leaching of washed from phosphorus phosphogypsum is 72,1%.

The insoluble residue is washed with water at T:W=1:0.3, and the humidity is ~27% when the content in the solid phase ~0,12% ∑(REM)2O3and 0.28% P2O5in terms of air-dry the product and moisture 0,54 g/l ∑(REM)2O3and ~ 0.5 g/l P2O5.

After water washing the insoluble residue of paramashiva the t with 40 g of finely ground limestone to neutralize the residual acidity of the aqueous phase (up to pH≈5,7) and remove it for disposal. This stands ~12 g of carbon dioxide (CO2).

The leaching solution (1650 cm3) stand for ≥2 h at bringing the concentration of sodium to ~1.2 g/l with the help of Na2SO4·10H2O for allocation from him by crystallization of the residue (concentrate) double sulfates of rare-earth metals and sodium. The resulting suspension of crystals of Na(REM)(SO4)2shared by filtering the mother liquor of the crystallization volume of ~ 1650 cm3content, g/l: 0,16 ∑(REM)2O3; ~1,4P2O5and ~245H2SO4and REM concentrate containing, % wt.: 26,8 ∑(REM)2O3; 0,18 P2O5; 7,60 Sa; 0,28 Pe2O3; 0,06 Al; 0,42 SiO2and 53,9 SO42-.

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

The mother liquor of crystallization is used in circulation for leaching of REE (and phosphorus), while the circulation of REM is 5-6%.

The washing liquor is insoluble residue in the amount of 300 cm3when content, g/l: 1,17 ∑(REM)2O3; 1,06P2O5and ~175H2SO4process the limestone with the formation of a slurry with a pH equal to 1.5 (i.e., a pH of less than pH start deposition of REE phosphates, which is equal to about 2.3) and ~20 g of carbon dioxide CO2. The latter may be disposed, for example, for the regeneration of soda if the use is of her for the conversion of the concentrate of the double sulphates of Na(REM)(SO 4)2in carbonates (REM)2(CO3)3.

The resulting slurry with a pH≈1.5 to unite with proryvnym solution of phosphogypsum. From an educated when this pulp in the amount of ~1200 cm3containing, g/l: 0,38 ∑(REM)2O3; 5,6P2O3and having a pH≈1,6 absorb REM a strongly acidic sulfonic cation exchanger gel structure (KU-2-8h) in H-form when air stirring and at room temperature.

From busy to 72 mg/g REE cation exchange resin is desorbed rare earth metals with a solution of ammonium nitrate to obtain commercial decorate with content ~0,42 g ∑(REM)2O3that corresponds to ~a 9.6%increase extraction of REE from phosphogypsum. The resulting desorbed can be processed into marketable products REE by known methods (using operations deposition, ion-exchange adsorption, liquid-liquid extraction and other). Uterine pulp (solution) sorption contains ~ 0.008 g/l ∑(REM)2O3and ~5.7 g/l P2O5. The degree of sorption extraction of rare-earth metals is ~97%.

From the mother of the pulp sorption precipitated phosphorus (and concomitant impurities (Fe, F, Al, and others) by treating her finely ground limestone to pH≈5,7 for air mixing. Air agitation of the pulp allows at pH≥5,6 oxidize oxygen ferrous iron and highlight it in the sediment. The resulting pulp is filtered and receive KEK - sediment (~95 g in terms of air-dry weight) with a phosphorus content of about 6.5% and 1170 cm3the filtrate concentration of phosphorus <0.2 g/l

Phosphorus-containing sludge is sent for recycling, for example, for the production of fertilizers, and the filtrate used as recycled water for making pulp of phosphogypsum and its flashing of phosphorus, as well as for washing the insoluble residue (gypsum) from phosphorus. Total recovery of REE from waste phosphogypsum in the concentrate in the form of double sulfates of rare-earth metals and sodium, and trademark desorbed REM is ~61.7 per cent, and taking into account REE contained in the mother solution, crystallization of REE and 67.8%.

Example 2. Processing 500 g of waste phosphogypsum in accordance with example 1. The difference is that after washing the phosphogypsum from phosphorus leaching from it REM lead at T:F=1:1.8 and within 25 minutes by stirring it with 650 cm3the mother liquor of crystallization of REE concentrate obtained in example 1, with the adjustment of the concentration of H2SO4to 22 wt.% using concentrated sulphuric acid.

As a result, the degree of extraction of rare-earth metals amounted to: in the leaching solution is to 70.2% (at a concentration of REE in solution 1,79 g/l); in concentrate ∑REE (double sulphates of sodium and REM) mass of ~4.1 g - 48,1% when the degree of crystallization of REE -90,5%, the content of rare-earth metals in concentrate at 27.1%; Mat is CNY solution crystallization concentrate REM - of 5.05%; commodity desorbed REM ~12.6 per cent; in the sediment during the precipitation of phosphorus from the mother of the pulp sorption of REE ~0,4%.

The content in the insoluble residue (plaster) was ~0.15% of ∑(REM)2O3and 0.32% P2O5. The concentration of P2O5in the mother solution, crystallization of the concentrate REE ~2,44 g/L. the Number of allocated WITH2when processing protractor insoluble residue (gypsum) ~3,5,

Total recovery of REE from waste phosphogypsum in the concentrate in the form of double sulfates of rare-earth metals, and sodium in commodity desorbed REM and in the mother liquor of crystallization REM - 65,7%.

The total loss of REM are ~34,3%, including insoluble residue (gypsum) to 33.9% and the precipitate obtained during the precipitation of phosphorus from the mother of the pulp sorption of REE ~0,4%.

Example 3. Processing 300 g of waste phosphogypsum in accordance with example 2. The difference is that after washing the phosphogypsum from phosphorus leaching from REM wet (~30%) of phosphogypsum are at T:W=1:2 within 25 minutes by stirring it with 420 cm3the mother liquor of crystallization of REE concentrate obtained according to example 2 with the adjustment of the concentration of H2SO4up to 30 wt.% using concentrated sulphuric acid.

The result of this experiment, the degree of extraction of rare-earth metals amounted to: in the leaching solution - 72% (at a concentration of R Is M ~1,67 g/l); concentrate ∑REE (double sulphates of sodium and REM) weight 2.64 g - 51,3% when the degree of crystallization of the rare - 91% and the content of rare-earth metals in concentrate ~27%; in the mother liquor of crystallization of the concentrate REE - 5.1% of the content of REE in atalina the phosphogypsum; trademark desorbed REM - 11,9%.

The content in the insoluble residue (plaster) was ~0,145% ∑(REM)2About3and 0.3% P2O5. The concentration of P2About5in the mother solution, crystallization of REE concentrate - is 3.21 g/l, the Number of allocated CO2when processing protractor insoluble residue (gypsum) ~10,

The amount of sediment obtained during the precipitation of phosphorus from the mother of the pulp sorption of REE - 44 g when the content of ~5% P2O5.

Total recovery of REE from waste phosphogypsum in the concentrate in the form of double sulfates of rare-earth metals and sodium, and trademark desorbed REM is 63,2%, and given the rare-earth metals contained in the mother solution, crystallization of REE - 68,3%.

The total loss of REM are ~31,7%, including insoluble residue (gypsum) 31.3% and with the precipitate, obtained by precipitation of phosphorus from the mother of the pulp sorption of REE - 0,36%.

It should be noted that the phosphorus concentration in the leaching solution will increase when used in the turnover of phosphate mother solutions of crystallization of REE as long as the amount of leached phospho shall not become equal to its number, the output from the process and primarily with proryvnym solution of phosphogypsum that it is possible to adjust the ratio of W:So with Reference to the examples, this corresponds to the concentration of phosphorus in terms of P2O5in the leaching solution in the range of 6-7 g/l

Since the numerical value of the degree of extraction of REE from phosphogypsum depends on the initial content of REM (with the same content of REE in the insoluble residue), important is to assess the specific loss of REM with an insoluble residue (gypsum) and other non-target products. Thus, patent-pending method total loss of REM with an insoluble residue (gypsum) and in the process of sorption of REE, during the precipitation of phosphorus from the mother of the pulp sorption of REE, are in the processing of 1 kg of phosphogypsum content of 0.44% ∑(REM)2O3about 1.4 g (respectively, 1.39 g (1,2+0,54·0,35) and 0.01 g) or 31.8 per cent.

For comparison, the loss of REM with an insoluble residue (gypsum) in the processing of 1 kg of phosphogypsum content of 0.44% ∑(REM)2O3according to the examples 1, 2 and 4, are shown in .RU 2337879, 1.7-2.0 g or 33.3-39,2%, 1-7% higher than in the patented method.

Removing the REM from phosphogypsum can be further increased by 1.0 to 1.5% increase in G:T, in the process of water washing the insoluble residue (gypsum), from 0.3 to 0.5. The feasibility of this is about is determined based on the present value of REM and operating costs.

Thus, as shown in the above examples, patent-pending method of phosphogypsum processing can virtually eliminate any significant precipitation of REE phosphates in the process sulfuric acid leaching by pre-water washing phosphogypsum from phosphorus. The method makes it possible to reduce the loss of REM due to water wash the insoluble residue (gypsum) and cation exchange sorption of REE from the wash water of phosphogypsum and the insoluble residue to obtain commercial decorate REM, and to provide a rational rotation with clean recycled water from impurities.

The obtained products - insoluble residue (gypsum) with P2O5<0.5%, the sediment increased to 5-6% P2O5and carbon dioxide can be efficiently disposed.

1. The method of processing of phosphogypsum, including leaching of rare earth metals (REE) and phosphorus acid with getting the leaching solution and the insoluble residue, the processing of the insoluble residue of the calcium compound to a pH of more than 5, the selection of REM concentrate from the leaching solution by crystallization, separation of REE concentrate from the mother liquor of crystallization, the addition stage leaching of REE and phosphorus, characterized in that before leaching the source fo fogies subjected to water washing of phosphorus with the receipt of the leaching solution, containing phosphorus and rare-earth metals at a pH not higher than the pH of the beginning of the deposition of REE phosphates, insoluble residue after leaching before processing the calcium compound is subjected to water washing, the obtained leaching solution is treated with a calcium compound with the formation of a slurry with a pH no higher than the pH of the beginning of the deposition of REE phosphates and unite with proryvnym solution of phosphogypsum from the obtained slurry REM absorb cation exchange resin, separating it from the mother of the pulp sorption and was stripped of his REM obtaining decorate and regenerated cation exchanger which is sent to the stage sorption of REE and desorbed - to receive concentrate REE, from the mother of the pulp sorption precipitated phosphorus and related impurities by treating the calcium compound to a pH of equal to or more than 5.5, the resulting slurry is separated into a residue, which is sent for recycling, and the aqueous phase, which is used as recycled water.

2. The method according to claim 1, characterized in that the water washing phosphogypsum from phosphorus is carried out in the pulp when W:T=1:1, and the division into the aqueous phase and phosphogypsum and water washing - by W:T=0,15-0,5 on the filter mode liquid displacement with getting the leaching solution by combining the aqueous phase and wash 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-to 2.2.

4. Spasibo to claim 1, characterized in that the leaching of lead within 20-25 minutes

5. The method according to claim 1, characterized in that the water washing the insoluble residue is performed on the filter with W:T=0,15-0,5-mode liquid displacement.

6. The method according to claim 1, characterized in that the washing liquor is treated with a calcium compound with the formation of a slurry with a pH of 1.5-2.0.

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

8. The method according to claim 1, characterized in that the cation use of strongly acidic sulfonation KU-2 gel structure or its analogs.

9. The method according to claim 1, characterized in that for water washing of phosphogypsum from phosphorus and water washing of the insoluble residue use recycled water.

10. The method according to claim 1, characterized in that the treatment of uterine pulp REE sorption by calcium compound is conducted at an air stirring.

11. The method according to claim 1, characterized in that the precipitate formed during the processing of the fallopian pulp REE sorption by calcium compound, sent for recycling of phosphorus.

12. The method according to claim 1, characterized in that calcium use limestone or quicklime or slaked lime, or a mixture thereof.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method includes leaching of rare-earth metals (REM) from phosphogypsum with 1-5% solution of sulphuric acid, REM sorption from leaching solution with cationite, REM desorption, precipitation of REM concentrate from desorbate, obtaining REM concentrate and mother liquor, which is used for REM desorption. Cationite after desorption is returned at sorption stage. Phosphor and fluorine are precipitated from mother liquor, phosphor -and fluorine-containing sediment are filtered and filtrate is used as return water in leaching. REM leaching and sorption are carried out simultaneously. Obtained pulp is filtered through mesh filter with separation of saturated REM cationite. After that, pulp is filtered with obtaining non-dissoluble residue and mother liquor of sorption. Before desorption cationite is treated with part of desorbate.

EFFECT: simplification of technology, reduction of duration of REM leaching and sorption, increased efficiency of sorption and desorption and concentrate quality.

12 cl, 1 dwg, 3 ex

FIELD: metallurgy.

SUBSTANCE: method includes dissolution of a sample of analysed alloy and separation of cerium from the base of the alloy and macrocomponents. At the same time the base and macrocomponents are separated from cerium by serial deposition and extraction of the alloy base and macrocomponents of the alloy from the solution. Deposition is carried out with sodium diethyldithiocarbamate, extraction - with dithizone in chloroform. After separation of the organic phase, the cerium content is detected in water phase with the spectrometric method.

EFFECT: elimination of harmful influence of high contents of iron and other components of steel and alloy base, improved quantitative analysis, higher accuracy and reproducibility of the analysis method.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention is meant for extracting rare-earth metals from phosphogypsum obtained in production of phosphorus fertiliser during sulphuric acid treatment of apatite. The method of extracting rare-earth metals from phosphogypsum involves converting phosphogypsum, dissolving the converted chalk to obtain an insoluble residue containing rare-earth metals. The obtained insoluble residue containing rare-earth metals is dissolved in nitric acid solution at solid-to-liquid ratio of 1:1.5 to obtain a solution and an insoluble residue. The insoluble residue is then washed with water; the obtained solution is mixed with the washing solution; the mixed solution is neutralised to acidity of 0.5-0.25 N with concentrated aqueous ammonia solution and taken for precipitation of rare-earth metal oxalates. The oxalates are precipitated with saturated oxalic acid solution; the residue is washed with 1.5-2.5% oxalic acid solution at solid-to-liquid ratio of 1:2-3. The oxalates are then dried and calcined until rare-earth metal oxides are obtained.

EFFECT: high efficiency of the process of extracting rare-earth metals by cutting duration of the process, the amount of reagents, the size of the equipment, energy resources and avoiding labour-consuming processes.

2 cl, 4 ex

FIELD: metallurgy.

SUBSTANCE: solid extractant is proposed (SEX) for extraction of scandium from scandium-containing solutions, containing a styrene divinyl benzene matrix with di-(2-ethyl hexyl)phosphoric acid. At the same time it additionally contains dibenzo-18-crown-6 at the following ratio of components, wt %: di-(2-ethyl hexyl)phosphoric acid 28-30, dibenzo-18-crown-6 28-30, styrene divinyl benzene - balance, besides, the ratio of styrene and divinyl benzene in the matrix is equal to 65÷70:30÷35. There is a method also suggested for production of the above extractant.

EFFECT: quite high selectivity by scandium and efficient separation of scandium and yttrium with their joint existence in a solution.

2 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to hydrometallurgical processing of mineral material, particularly scandium-containing "tailings" obtained during beneficiation of titanium-magnetite ore by wet magnetic separation. The method of extracting scandium is three-step sulphuric acid leaching of scandium, wherein at the first step, leaching is carried out with recycled solution after extraction of scandium at temperature of 30-50°C and solid to liquid ratio of 1:6-7 for 3-4 hours; the pulp is then divided into a solid phase and a liquid phase; at the second step, a portion of the solution obtained from the first step is returned to the solid phase and sulphuric acid is added to concentration of 340-360 g/l and sodium fluoride is added in amount of 20-25 kg fluorine/t solid; leaching is carried out at temperature of 95-98°C and solid to liquid ratio of 1:2.5-3 for 3-4 hours; further, at the third step, the pulp is diluted in solid to liquid ratio of 1:6.5-7.5; treatment is carried out at temperature of 95-98°C for 3-4 hours.

EFFECT: invention increases extraction of scandium, cuts the overall duration of the leaching process and consumption of sulphuric acid and sodium fluoride.

3 ex, 1 tbl

FIELD: metallurgy.

SUBSTANCE: proposed method comprises sulfuric acid leaching of scandium from red mud, pulp filtration, scandium sorption from sulfuric acid solutions, desorption from organic phase by carbonate solution to obtain column effluent. Then, scandium poorly soluble compounds are precipitated from column effluent, precipitate is filtered out, flushed, dried and annealed to get scandium-bearing concentrate. Note here that said leaching is performed by 10.0-13.5%-sulfuric acid at pulp initial vibration cavitation at rotary velocity of 35-60 m/s for 15-35 min. Scandium is precipitated from column effluent by potassium caprinate in amount of 75-100 g/t of scandium at pH 3.5-4.5 and exposure for 15-25 min.

EFFECT: increased yield.

3 cl, 2 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises extraction of rare-earth metal cations by organic phase including extragent solution in inert diluter. Naphthenic acid is used as said extragent. Kerosene is used as inert diluter. Extraction is conducted in three stages at relationship between organic and aqueous phases O:A=1·(9-11) at every stage. Note here that, at first stage, europium cations (III) are extracted at content of naphthenic acid in kerosene of 10-13 vol. % and aqueous solution pH 5.0-5.1. At second stage, samarium cations (III) are extracted at content of naphthenic acid in kerosene of 13-16 vol. % and aqueous solution pH 4.6-4.7. At third stage cerium and lanthanum cations (III) are extracted at the same content of extragent and pH 5.0-5.1.

EFFECT: higher yield.

4 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: method of extracting rare-earth metals from solutions containing iron (III) and aluminium comprises sorption of rare-earth metals on sorbent. Ampholyte with iminodiacetic functional groups is used as said sorbent. Sorption is carried out after preliminary neutralisation or acidification of solution to pH 4-5 by whatever alkaline or acid agent to add ampholyte in obtained pulp with separation of solid fraction. Sorption is conducted at ampholyte:pulp ratio of 1:50-1:150, phase contact time of 3-6 h and in the presence of reducing agent.

EFFECT: higher selectivity.

5 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to methods of separating deactivated rare-earth elements during nitric acid treatment of apatite concentrate from nitrate-phosphate solutions. The method of treating a rare-earth phosphate concentrate isolated from apatite involves decomposition of the rare-earth phosphate concentrate with nitric acid, treating the obtained solution with oxalic acid with precipitation of rare-earth oxalates in two steps, at the first step of precipitation of oxalates of thorium and rare-earth elements, 5-10% oxalic acid in stoichiometric amount is added to rare-earth elements present in the solution, and at the second step of precipitation of rare-earth oxalates, 110-115% oxalic acid in stoichiometric amount is added to rare-earth elements present in the initial solution, and the rare-earth oxalates are then calcined to rare-earth oxides.

EFFECT: invention provides high economic efficiency of the process, which is achieved by avoiding the need to process and bury the precipitate containing thorium.

3 cl, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises multistep leaching of red slag by the mix of sodium carbonate and bicarbonate on forcing annealing furnace flue gases containing carbon dioxide there through to obtained solution. Then, three-step holding of said solution at increased temperatures is performed along with selective separation of precipitates after every said step. At first step, said solution is heated to temperature not exceeding 80°C for, at least, 1 hour. Thereafter, it is settled for, at least, two hours at natural cooling. At second step, said solution is boiled and mixed for, at least, two hours. At third step, said solution is evaporated to 50% of initial volume to add 46%-solution of sodium hydroxide to concentration of Na2Ocaustic of 1.5-2.0 kg/m3. Now, it is boiled for, at least, 2 hours and precipitate containing scandium oxide is settled for 10-16 hours at natural cooling.

EFFECT: simplified process, higher yield of scandium oxide.

1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to production of high-strength inorganic pigments which can be used to produce paint materials. The method of producing an iron-calcium pigment involves neutralisation of iron-containing spent solutions, containing sulphuric acid, with a calcium-containing reagent with deposition of a precipitate, filtration and drying the precipitate. The iron-containing spent solution used is waste water from abandoned deposits of iron-copper-zinc sulphide ores containing iron (III) sulphate and sulphuric acid. The waste water is neutralised until achieving reaction mixture pH of 4-5.

EFFECT: simple process and recycling of under-waste dump and quarry water from spent complex deposits.

2 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing an anticorrosion pigment containing iron phosphate. The method involves adding phosphoric acid solution to iron (II) sulphate solution and neutralising the obtained solution with a product containing amine groups. Neutralisation is carried out until pH 5.5-8 is achieved and a precipitate is obtained. The precipitate is then filtered, washed and dried. The product containing amine groups used is polyethylene polyamine and the precipitate is dried at 50-65°C.

EFFECT: improved anticorrosion properties of the pigment and low production cost thereof.

1 tbl, 3 ex

FIELD: process engineering.

SUBSTANCE: invention relates to hydrometallurgy of copper and nickel and may be used for processing sulphate solutions of copper and nickel. Proposed method comprises nickel sulphate crystallisation. Note here that, prior to crystallisation, solution is processed by ammonia water to pH of 4-4.5 at not over 60°C. Nickel sulphate double salt is subjected to isohydric crystallisation with reaction volume cooling to 15-25°C and separation of crystallised double salt from amorphous phase of appropriate component and mother solution. Said separation is carried out in upflow at variable hydrodynamic conditions created by mother solution at its linear rate of 6-8 m/h.

EFFECT: simplified process, decrease fire hazard.

2 cl, 1 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: method involves treatment of the sulphide concentrate with aqueous ammonia solution and with hydrogen peroxide solution after heating to obtain a solution containing rhenium and platinum. After treating the sulphide concentrate, an insoluble residue and the obtained solution which contains rhenium and platinum are separated, treated with sulphuric acid to pH 0.0-1.0. The solution is then heated and held and the formed residue of platinum compounds is separated from the rhenium solution.

EFFECT: possibility of separating platinum and rhenium at the step for extracting rhenium from sulphide concentrate.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: method involves simultaneous extraction of platinum and rhenium from acid solutions by introducing to the solution of sulphur-containing reducing agent (sodium thiosulfate). Then, deposit of sulphides and other connections of rhenium and platinum is separated from the solution. At that, sodium thiosulfate is added in the form of water solution by its uniform continuous supply to hot acid solution containing platinum and rhenium at the ratio of masses of reagent and soluble rhenium and platinum of 15 to 23.

EFFECT: reducing the flow of sulphur-containing reagent and increasing the extraction degree of platinum from acid solution to the concentrate owing to changing the procedure of introducing the precipitator reagent to acid solution containing platinum and rhenium.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing iron-containing coagulant from spent chloride and sulphate etching solutions of steel rolling mills, and can be used in ecology and water treatment. The method of preparing iron-containing coagulant involves oxidation of iron (II) to iron (III) with sodium hypochlorite as an oxidising agent. Concentrated solutions of the coagulant are obtained by oxidising spent etching solutions containing iron (II) sulphate and chloride. The obtained suspension is treated with mineral acid until the precipitate dissolves. The oxidation process takes place at room temperature.

EFFECT: method simplifies and improves the process of recycling spent etching solutions, and reduces formation of by-products which pollute the environment; method enables to include all types of iron-containing spent etching solutions into the recycling cycle.

2 tbl, 4 ex

FIELD: metallurgy.

SUBSTANCE: procedure for production of palladium soluble in nitric acid consists in reduction of suspension of powder of palladium compound. As palladium compound (II) there is used trans-di-ammine-chloride of palladium (II). Reduction is carried out at 50-110°C with addition of 20-50 % water solution of sodium formate or 20-70 % water solution of ammonia formate, acidulous with concentrated formic acid to value of pH 3-5 heated to 50-110°C and taken at amount of 110-150 % from mole amount of palladium. Reduction is performed at presence of ice acetic acid or its concentrated 70-100 % water solution taken at amount of 200-400 % of mole amount of palladium.

EFFECT: stability and simplicity of production of palladium practically completely soluble in nitric acid.

2 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: procedure for production of palladium soluble in nitric acid consists in reduction of water solution of palladium compound. As source water solution of palladium compound there is used hydrochloric acid water solution of tetra-chlorine-palladium acid evaporated to the beginning of palladium chloride crystallisation (II). Reduction is carried out at 50-110°C with addition of 20-50 % water solution of sodium formate or 20-70 % water solution of ammonia formate, or 70-95 % water solution of formic acid heated to 50-110°C and taken at amount of 110-150 % from mole amount of palladium. Also, reduction is realised when acidity of solution reaches pH 3-5 with addition of 5-15 % of water solution of ammonia.

EFFECT: stability and simplicity of palladium production.

2 cl, 3 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: method involves depositing citric acid from a nitrate solution at temperature 50-90°C and washing the obtained precipitate with water. The precipitate is dried after washing. Bismuth citrate is deposited from the nitrate solution which contains lead and silver impurities, with molar ratio of citric acid to bismuth equal to 0.90-0.99.

EFFECT: high degree of extracting citric acid into the end product and its purity.

1 tbl, 3 ex

FIELD: metallurgy.

SUBSTANCE: procedure for extraction of hydrochloric acid solutions consists in sedimentation of rubidium and in crystallising sediment in form of rubidium hexa-chlorid-tellurite. Sedimentation from hydrochloric solutions is performed with normality of hydrochloric acid within the range 6-12 n with solid tellurium dioxide. The process is carried out at 20-25°C with mixing during 3 hours.

EFFECT: improved separation and increased degree of rubidium extraction.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: method includes leaching of rare-earth metals (REM) from phosphogypsum with 1-5% solution of sulphuric acid, REM sorption from leaching solution with cationite, REM desorption, precipitation of REM concentrate from desorbate, obtaining REM concentrate and mother liquor, which is used for REM desorption. Cationite after desorption is returned at sorption stage. Phosphor and fluorine are precipitated from mother liquor, phosphor -and fluorine-containing sediment are filtered and filtrate is used as return water in leaching. REM leaching and sorption are carried out simultaneously. Obtained pulp is filtered through mesh filter with separation of saturated REM cationite. After that, pulp is filtered with obtaining non-dissoluble residue and mother liquor of sorption. Before desorption cationite is treated with part of desorbate.

EFFECT: simplification of technology, reduction of duration of REM leaching and sorption, increased efficiency of sorption and desorption and concentrate quality.

12 cl, 1 dwg, 3 ex

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