Method of production of phosphoric acid

FIELD: production of pure phosphoric acid and calcium monohydrophosphate.

SUBSTANCE: proposed method includes decomposition of phosphate ore by first hydrochloric acid solution at concentration not exceeding 10 mass-%, separation of liquid decomposition product into insoluble solid phase containing admixtures and separate aqueous phase containing phosphate, chloride and calcium ions in form of solution, neutralization of aqueous phase separated from liquid decomposition product by adding calcium compound for obtaining insoluble settled-out calcium phosphate by means of phosphate ions, separation of neutralized aqueous phase into aqueous phase containing calcium and chloride ions in form of solution and settled solid phase on base of water-insoluble calcium phosphate and dissolving of at least part of separated settled solid phase in second aqueous hydrochloric acid solution containing hydrochloric acid in the amount exceeding its content in first hydrochloric acid solution, thus forming aqueous solution containing phosphate, chloride and calcium ions extracted by organic extracting agent at extraction in "liquid-liquid" system. Proposed method makes it possible to avoid fine grinding or roasting of ore.

EFFECT: enhanced efficiency of extraction for production of pure concentrated phosphoric acid solution with no contamination of surrounding medium.

24 cl, 2 dwg, 1 tbl, 4 ex

 

The technical field to which the invention relates.

The present invention relates to a method for producing phosphoric acid, in particular, pure phosphoric acid, which comprises the following steps:

at least disposable decomposition of phosphate ore first aqueous hydrochloric acid solution to form a liquid decomposition product,

the first separation liquid decomposition product insoluble solid phase impurities and separate the aqueous phase containing in solution the ions of phosphate, chloride and calcium,

extraction of an aqueous solution containing phosphate ions, chloride and calcium, organic extractant to obtain the extraction of the aqueous phase with the content

ions of chlorine and calcium and extraction of the organic phase with phosphoric acid,

repeated extraction of the extraction of the organic phase the aqueous re-extractant for the separation of the aqueous phase obtained by re-extraction and ion-containing phosphate, and optional

- concentrated aqueous phase, obtained by re-extraction, education, clean water phosphate solution.

Prior art

Well-known methods of this type, which use a means of hydrochloric acid decomposition of the ore and extraction system "liquid-liquid" liquid f is s, obtained by separation of the insoluble substances from the liquid product of the decomposition (see, for example, U.S. patent No. 3304157, England No. 1051521 and Spain No. 2013211, and article I.M.I. Staff Repot, Development and implementation of solvent extraction processes in the chemical process industries, in Proc. Int. Solv. Extr. Conference, ISEC'71, ggage, 19-23 April, 1971, issue # 94).

These methods have the disadvantage that the decomposition is applied, usually hydrochloric acid with concentration up to 20 and even 30 wt.%. Used ore must be of high quality, i.e. to have a high content of P2About5when this is required, as a rule, its fine grinding, which increases costs. During the decomposition of the intense heat caused not only by ekzotermicheskie reactions, but also secreted by dissolving energy, therefore, it is difficult separating insoluble substances, as the liquid decomposition product is viscous and contains organic substances that have fallen from the ore. Due to the high temperature and the concentration of hydrochloric acid solution there are significant problems in relation to corrosion.

Another major drawback of these methods is the extraction of relatively depleted content of P2O5the aqueous phase using an organic solvent. The content of P2O5it is not Bo is her 5-6 wt.%. Therefore, extraction is complicated, has a low efficiency, and at the stage of concentration of the aqueous phosphoric acid solution obtained after re-extraction, spent a large amount of energy.

Finally, from the aqueous phase obtained by extraction and containing in solution CaCl2and hydrochloric acid, it is necessary to remove traces recorded organic solvent. However, this aqueous phase is very large and at this stage also requires a large amount of energy, in particular, in the case when applied distillation with water vapor.

Also known way means of hydrochloric acid decomposition, in which the ore is subjected to an initial limited decomposition of dilute hydrochloric acid. Enriched thus the content of P2O5fraction passes then re-decomposition of a concentrated hydrochloric acid, then extraction is carried out in the system "liquid-liquid" to produce phosphoric acid (see US-A-3.988.420).

There are also many other ways of obtaining phosphoric acid, for example, thermal method, based on the combustion of phosphorus, or wet methods, also based on the decomposition of phosphate rock with acid, usually sulfuric, and these methods allow the plaster in large quantities as a by-product is.

The aim of the present invention is to provide an improved method for the production of phosphoric acid and/or its salt is wet, by means of hydrochloric acid decomposition. This method should eliminate the above disadvantages, in particular, fine grinding or roasting of ore extracted, without any special requirements to its quality, it must provide an effective extraction system "liquid-liquid" to obtain pure concentrated phosphate solution without polluting the environment.

Disclosure of beings inventions

These problems are solved according to the invention using the above method, comprising the following stages:

- neutralization of the aqueous phase separated from the liquid product of decomposition, the addition of calcium to obtain using ions of the water-insoluble phosphate, precipitated calcium phosphate,

the second division of the neutralized aqueous phase to a water phase content in the form of a solution of calcium ions and chloride and the precipitated solid phase based on water-insoluble calcium phosphate,

- dissolution of at least part of the selected precipitated solid phase in the second aqueous hydrochloric acid solution with formation of an aqueous solution containing phosphate ions, chloride and calcium extractable organic extractant.

E is from the method has an advantage consists in the decomposition of the ore with a moderate content of P2O5the first fraction of hydrochloric acid, which may be diluted, in the separation of the solid enriched content of P2About5phase, free from prosloennyh, water-insoluble substances, and the dissolution of the specified solid enriched content of P2O5the second phase more concentrated fraction of hydrochloric acid. As means of hydrochloric acid decomposition proceeds in diluted and, therefore, a discrepancy of environment, the Department of insoluble substances is done simply and quickly, the heat dissipation is absent during decomposition, which effectively takes place at ambient temperature, while largely solved the problems of corrosion caused by hydrochloric acid.

In addition, the extraction system "liquid-liquid" is dissolved, liquid, rich in content of P2O5phase and, consequently, the efficiency can be substantially improved. For example, the number of stages of extraction can be greatly reduced, while for a possible final concentration requires less energy consumption compared with the prior art.

In the method according to the invention the quality of the ore is not of great importance. The content of P2About5it can SOS is hawlati, for example, 15-38 wt.%, that does not cause difficulties, and, therefore, can be applied ore optimal value. For example, you can use ore containing 20-38 wt.% P2O5, 34-40 wt.% Sa and 5-10 wt.% impurities when the ratio between CA and P=1.5 and 2.4.

In the subsequent neutralization get a residue, which is "enriched" P2O5and purified in comparison with the ore, since the content of P2O5it can reach 40 to 50 wt.%.

Ore does not require fine-grind, and it may contain a particle size of about 150-500 microns.

Applied decomposition of hydrochloric acid is largely diluted. Optimally, to its maximum content in water was 10 wt.%, mostly 3-6 wt.%, preferably 5 wt.% or less. Therefore, such a decomposition, which is slightly aggressive and flowing in a discrepancy of environment, has a high selectivity, i.e. there is preferential and complete dissolution of P2O5and minor dissolution of impurities. The separation of insoluble and prosloennyh substances is simply and completely, which allows then to obtain an insoluble salt of sulfate, "enriched" by the content of P2O5and substantially purified from impurities. The molar ratio between HCl and CA in the liquid decomposition product is pre is respectfully from 0.6 to 1.3, optimally from 0.7 to 1.2.

Thus, the method according to the invention allows the use of ore with a poor content of P2O5for example, ore impurities Fe and Mg, providing the user greater flexibility when choosing ore on the market. It also allows the use of dilute hydrochloric acid with a lower price and eliminate the difficulties associated with viscosity and intense heat during decomposition.

Separation of liquid product decomposition can be done in any suitable way, for example by filtration, sedimentation or a similar method.

The resulting aqueous solution contains in solution calcium chloride CaCl2, phosphoric acid and water-soluble dihydrophosphate calcium (MCP), the solution is subjected to neutralization.

At the stage of neutralization specified in aqueous solution administered a calcium compound, for example, calcium hydroxide, calcium oxide or water-soluble salt of calcium, such as calcium carbonate.

With increasing pH is formed of water-insoluble monohydratefast calcium (DCP)precipitated.

This precipitate can be separated, e.g. by filtration. The resulting cake may contain, for example, 40-50% R2O5, 25-28% CA and possible slight traces of impurities.

For dissolving monohydrogenphosphate calcium (DCP) again apply salt to the slot, but with a higher concentration, for example, 15-20 wt.%. Get a clear solution as insoluble substances are removed, the rate of extraction will be optimal, since the content of P2O5in solubilizing solution is relatively high, of the order of 8-15 wt.%, mostly 10-13 wt.%.

In the extraction step can be applied to any suitable organic extractant, for example, extractants, recommended in patents US-A-3304157, GB-1051521, GB-1142719, FR-1427531 and FR-1396077, in particular n-butanol.

In a preferred embodiment of the invention, the method further includes, after the extraction leaching extraction of the organic phase fraction of the aqueous phase, obtained by repeating the extraction, removal of the organic extraction phase of hydrochloric acid and calcium chloride, as well as possible residual impurities. After re-extraction obtain an aqueous solution with a content of 15-25 wt.% P2O5that indicates a very high efficiency. In addition, the residual HCl content can reach in some cases 1-5 wt.%, to reduce the recirculation HCl, and are caused by corrosion problems.

According to a variant of development of the invention the method further includes distillation with water vapor traces of organic extractant from the aqueous extra the operating phase, containing chloride ions and calcium.

As is known, traces of organic extractant is extracted from the aqueous phase obtained by extraction in the system "liquid-liquid". However, in the method according to the invention the part of CaCl2removed as a by-product, has already been allocated in the division conducted after deposition of monohydrogenphosphate calcium (DCP). Here this part can be removed in the form in which it was present, without special purification stages. An aqueous solution of CaCl2obtained extraction liquid, enriched in the content of P2O5phase according to the invention, is present in a substantially smaller volume compared with the volume known from the prior art that requires a significantly smaller amount of steam for the distillation of the organic extractant.

According to a variant of development of the invention the method further includes processing the aqueous phase obtained in the second division and containing in solution the ions of calcium and chloride, aqueous sulfuric acid solution with the formation of insoluble calcium sulfate, precipitated, and the aqueous phase on the basis of hydrochloric acid, separating the precipitate of calcium sulfate and at least partial recycling of the aqueous phase on the basis of hydrochloric acid to obtain the first and/or second aqueous hydrochloric acid solution. Also m is tenderly to plan the use of the method according to the invention in the industrial sectors, which do not contain hydrochloric acid. Recycled hydrochloric acid has a high degree of purity and does not require frequent updates.

Thus, we can assume that the method according to the invention can be applied in two successive modules, the first of which is designed to produce a solid phase on the basis of monohydrogenphosphate calcium (DCP), and the second for the production of phosphoric acid from the solid phase on the basis of monohydrogenphosphate calcium. Due to the lack of material flow, linking these both modules, there is no need in the immediate following stages are carried out in the second module, the stages undertaken in the first module. Thus, it is possible to provide, for example, drying of the solid phase on the basis of monohydrogenphosphate calcium (DCP), obtained after precipitation and separation of monohydrogenphosphate calcium, keeping this dry solid phase and even transporting it to a site different from the site of conduction phases of the first module.

Therefore, the present invention may include a method in which at least part of the obtained deposition of monohydrogenphosphate calcium (DCP) is used for purposes other than as a base material for the second module. For example, salt of phosphoric acid can be used as fertilizer or as feed for livestock is.

The present invention includes a stage which is provided for each module separately.

Therefore, the invention also concerns the method of obtaining salt of phosphoric acid.

A known method of producing monohydrogenphosphate calcium (DCP), including:

- at least one-time decomposition of the phosphate ore aqueous hydrochloric acid solution to form a liquid decomposition product,

the first separation liquid decomposition product insoluble solid phase and aqueous phase,

- neutralization of selected aqueous phase by the addition of calcium to education using the contained ions of the water-insoluble phosphate calcium phosphate, precipitated,

the second division of the neutralized aqueous phase to the liquid phase and the precipitated solid phase based on water-insoluble calcium phosphate (see the already mentioned patent US-A-3.988.420).

This method is really the way in which separated from the liquid product of the decomposition of the aqueous phase maximally depleted phosphate ions which can be extracted in the form of monohydrogenphosphate calcium (DCP) simultaneously with the production of phosphoric acid.

Also known is a method of obtaining monohydrogenphosphate calcium decomposition of concentrated ore (35%) hydrochloric acid solution with inherent everything and the above shortcomings (see SU-A-1470663).

In contrast to the above described method known from US-A-3.988.420, the present invention provides that when the decomposition of phosphate rock was the dissolution of the contained phosphate, with liquid decomposition product contains phosphate in the form of ions, and so separated from the liquid product of the decomposition of the solid phase contained impurities and separated from the product of the decomposition of the aqueous phase contains phosphate ions, chloride and calcium, and in these phases, the aqueous phase is subjected to neutralization and the second partition.

The invention relates also to a method for producing phosphoric acid, including:

- dissolution of the solid phase on the basis of water-insoluble calcium phosphate in an aqueous hydrochloric acid solution with the formation of solubilizing aqueous solution containing phosphate ions, chloride and calcium,

extraction solubilizing aqueous solution with an organic extractant to obtain the extraction of the aqueous phase with a content of chloride ions and calcium and obtain the extraction of the organic phase with phosphoric acid,

repeated extraction of the extraction of the organic phase the aqueous re-extractant for separation of the aqueous phase obtained by re-extraction and containing phosphate ions and, if necessary

- concentrated floor is obtained when re-extraction of the aqueous phase for the formation of a pure aqueous phosphate solution.

Therefore, the invention also includes obtaining phosphoric acid from the solid monohydrogenphosphate calcium (DCP), available on the market and produced in some cases by any means.

Other embodiments of the methods according to the invention are indicated in the following claims.

Details and features of the invention are the following, unlimited description of embodiments of the method according to the invention with reference to the attached drawings.

Brief description of drawings

Figure 1 presents in a processing schema module for the purification and enrichment of ore used in the embodiment of the method according to the invention,

figure 2 presents in a processing schema module for the production of phosphoric acid used in the embodiment of the method according to the invention.

As shown in figure 1, mined phosphate ore is fed through pipe 1 into the container 2 for the decomposition to which it is exposed to hydrochloric acid solution with a concentration of about 5 wt.%, coming into this tank through the pipeline 3. Under phosphate ore refers to the ore, which is not subject to burning or fine grinding and which was produced, in particular, in the mines, on which it has a powder form. If Viladomat ore is of volcanic origin, it may be provided with its disposable grinding until the particle size of the order of 150-500 μm.

In the vessel 2 for the decomposition is rapid and intense dissolution of calcium phosphate with obtaining H3PO4and soluble dihydrophosphate calcium (MCP). The obtained turbid liquid is supplied by pipeline 4 in the separating device 5, for example, a filter press, in which the undissolved solid substances are discharged through 6 after the addition of the corresponding effective accelerator filtration and discarded.

Formed by separation of the liquid phase contains dissolved phosphoric acid, monocalcium phosphate (MCP), calcium chloride and some residual impurities. The decomposition efficiency is more than 80 wt.%, preferably 90 wt.% and particularly preferably 95 wt.%, when the ambient temperature.

Then the liquid phase separated from the liquid decomposition product, is supplied by pipeline 7 in the capacity of 8 to neutralize, which precipitated decalcify phosphate (DCP) introducing into the liquid phase derived calcium through 9 for the increase in pH, such as calcium carbonate or lime milk.

To the precipitate, for example, to send the neutralized liquid phase 10 and submit it on the belt filter 11, which separates the solids, i.e. the wet cake from 12 D. calzavara phosphate, containing approximately 40-50 wt.% P2O5in terms of dry, 25-28% CA and possible traces of impurities. The filtrate is removed through 13. He is an aqueous solution of CaCl2that can easily be removed, so as slightly polluted, and can even be easily reused. Calcium chloride can be used, for example, on roads as an anti-icer.

Very pure aqueous solution of CaCl2you can also send through the pipeline 41 to the reactor 42, fed by pipeline 43 aqueous sulfuric acid solution. In this reactor, stirred at a temperature of about 60°C for 1 hour, insoluble calcium sulfate, which precipitates in a very pure form. The liquid formed when sulfuric acid decomposition is supplied by pipeline 44 separation produced, for example, the filter 45. The formed solid phase of calcium sulfate is discharged at 46, and the liquid phase formed of high-purity hydrochloric acid solution flows through the pipe 47 into the pipeline feeding the diluted hydrochloric acid 3.

Given that sulfuric acid is more common and is present in large quantities in comparison with hydrochloric acid, the recycling allows to further increase the efficiency of hydrochloric acid decomposition and hold it even in places where hydrochloric acid assessability.

Using shown in figure 2 of the module can be made of pure phosphoric acid extraction in the system "liquid-liquid". With this aim, salt ducellier phosphate DCP, obtained, for example, in the form of a cake on plot 12 band filter 11 serves on line 14 into the container 15 on dissolution, in which it is dissolved under the action of the incoming 16 hydrochloric acid. However, in this case, this stage is carried out using a more concentrated hydrochloric acid, for example, at a concentration of 15-20 wt.%. Such dissolution allows you to prepare an aqueous solution with a content of phosphoric acid in the mixture with CaCl2soluble salt of calcium chloride. This solution contains P2O5in an amount of about 10-12 wt.%, that can improve the performance and migration at the site for subsequent extraction operations in the system "liquid-liquid" and get a second extraction of the concentrated phosphate solutions.

Removing insoluble substances conducted during the decomposition vessel 2, which avoids the extraction system "liquid-liquid" problems associated with the formation of emulsions during processing of the aqueous phase with an organic solvent. The use of purified and enriched the content of P2O5monohydrogenphosphate calcium (DCP) for the preparation of the original aq is phase extraction provides increased flexibility when choosing ore and reduces the number of stages of extraction.

Solubilization the water phase is then served by pipeline 38 in the extraction column 17, which comes prototechno pipeline 18 organic solvent, e.g. n-butanol as a solvent. Organic solvent selectively extracts the P2O5from the aqueous phase and goes with him to pipe 39 in the wash column 19, and then through the pipeline 20 to the column 21 re-extraction.

In column 21 of re-extraction of the organic phase is brought into contact with water supplied prototechno on line 22. Water extracts P2O5from the organic phase. The resulting aqueous phase is drained from the column 21 through the pipe 23 and is directed partly in the hub 24 to the pipe 25 and partially in the leaching column 19 through the pipeline 26. Here the aqueous phase with a content of P2O5used for countercurrent washing of the organic phase to remove chloride and residual impurities that are not removed is depicted in figure 1 module, then the aqueous phase is fed back through the pipe 27 into the tank 15 to the dissolution.

The organic phase obtained by re-extraction, is supplied by pipeline 28 in the extraction column 17.

The hub 24 may be a conventional trehkorpusny evaporation apparatus, which sequentially evaporated traces RA is the solvent, received in the extraction column 17 through the pipe 29, hydrochloric acid contained in the solution and supplied through a pipeline 30 in the supply pipe 16 for dissolution ducellier phosphate, and a large quantity of water supplied to the pipe 31. Phosphoric acid is discharged through pipes 33 in the form of concentrated purified solution.

Obtained in the extraction column 17 the aqueous phase is supplied by pipeline 34 to the column 35 distillation with water vapor. Water vapor enters the column 36 and captures contained in the aqueous phase of an organic solvent. Captured water vapor of organic solvent is given in the extraction column 17 through the pipe 37. An aqueous solution of CaCl2that can be further processed for removal of some heavy metals, can also be discharged through the pipeline 40.

As can be concluded that only part of CaCl2formed after the introduction of HCl in the process, must be processed by distillation with water steam, which dramatically reduces energy costs compared with the methods using extraction system "liquid-liquid" directly to the liquid phase separated from the liquid formed by means of hydrochloric acid decomposition. Below the invention is described more in detail with the help of examples of its implementation with unlimited character.

Example 1

Phosphate ore is of Moroccan origin fed into the reactor with stirring in the amount of 15 kg/h, which is affected by hydrochloric acid solution with a concentration of 5 wt.%. The quantity of hydrochloric acid solution is 141 l/h, resulting in the ratio of HCl/CA reaches 0,7.

The residence time in the reactor is 30 minutes. After passing through the intermediate tank (with a duration of being in it for about 1 h) non-viscous liquid decomposition product is fed into the filter press. When this is applied ambient temperature. In the filter press is insoluble substances are separated.

Emerging from filter press solution is fed in the amount of 188 l/h in two consecutive reactor for neutralization. Calcium carbonate is fed to them in the amount of 5.8 kg/h, which corresponds to a molar ratio between CA and P=1. The residence time in both reactors is 100 minutes.

Upon completion of the reaction and the formation of monohydrogenphosphate calcium (DCP) in the pulp at the site of the second reactor neutralization add a small amount of milk of lime to extract phosphate. The concentration of lime milk is 245 g of CA(Oh)2/kg, and the quantity supplied to the second reactor of 3 l/h

Then the neutralized slurry is served on a belt filter. Received ke is composed mostly of monohydrogenphosphate calcium (DCP).

Additive CA(Oh)2calculated taking into account the pulp with a molar ratio CA/P=0,2. The pH of the filtered mother solutions is about 5, the residual quantity of phosphate in them is less than 1 g/kg

Example 2

Apply the same conditions as in example 1, but in the neutralization reactors, enter only the calcium carbonate in the amount of 7.1 kg/h, resulting in a molar ratio of CA and P is 1.2.

The table below shows the composition of the different products obtained in the process described in example 1.

Table
Humidity, %P2O5, % m/mCA, mg/kgCl, mg/kgNa, mg/kgK, mg/kgMg, mg/kgF, mg/kgSO4mg/kgSi, mg/kgFe, mg/kgAs, mg/kg
The filtrate dihydrophosphate calcium (MCP)was 2.76283654773512450505022,00,68
Cake containing: insoluble substances, all substances soluble substance33,92 13,52325430168352896585545207384122369200370012
3,313632737516
Cake from monohydrogenphosphate calcium (DCP)Dry36,27289008803623,55842,01
Humidity %Al mg/kgCd, mg/kgCu, mg/kgPb, mg/kgZn, mg/kgNi, mg/kgCr, mg/kgTi, mg/kgV, mg/kgU, mg/kg
The filtrate dihydrophosphate calcium (MCP)41,80,420,319,5a 3.96,233,03.1
Cake from monohydrogenphosphate calcium (DCP)Dry1390,651,33,7363,5737,656

Example 3A

In the reactor with stirring with a capacity of 2 l was continuously mixed solution with a content of 15% CaCl2similar to the filtered stock solution of example 1 was supplied at a rate of 4 kg/h, with a concentrated (96%) sulfuric acid. The amount of sulfuric acid was 0.54 kg/h

The duration of stay in the reactor for 30 minutes.

The slurry formed after the appearance of crystals of gypsum, was filed on filter Buchnera. The reaction temperature was 40°C. the Solution was withdrawn from the filter number 3,36 kg/h and contained mainly (10%) hydrochloric acid. It was applied over a portion of the reactor for the decomposition of the ore in the new cycle. Gypsum cake (1,18 kg/h at 30% moisture content) was washed and then removed. Washing solutions are recycled together with the filtrate. The resulting cake contains mainly two-water calcium sulfate.

Additive sulfuric acid was calculated taking into account the pulp with a molar ratio of Ca/H2SO4=1.

The composition of the extracted hydrochloric acid solution:

S0=4: C./million

CA++: 3749 hours/million

Cl-: 99507 hours/million

Example 3b

In the reactor with stirring with a capacity of 2 l was continuously mixed solution with a content of 15% CaCl2supplied in quantities of 4 kg/h, with a concentrated (96%) ser is Oh acid. The amount of sulfuric acid was 0.48 kg/h

The duration of stay in the reactor for 30 minutes.

The slurry formed after the appearance of crystals of gypsum, was filed on filter Buchnera. The reaction temperature was 40°C. the Solution vyvalivshis of filter number 3,41 kg/h and contained mainly (10%) hydrochloric acid, was applied over a portion of the reactor for the decomposition of the ore in the new cycle. Gypsum cake (1.062 kg/h at 30% moisture content) was washed and then removed. Washing solutions are recycled together with the filtrate. The resulting cake contains mainly two-water calcium sulfate.

Additive sulfuric acid was calculated taking into account the pulp with a molar ratio of Ca/H2SO4=0,9.

The composition of the extracted hydrochloric acid solution:

SO=4: 11045 h/million

CA++: 6978 hours/million

Cl-: 101846 hours/million

Example 4

Decomposing decalcify phosphate obtained by the method of example 1, 20%hydrochloric acid solution. The composition of the liquid obtained after dissolution: 20% N3PO4, 10% HCl, 10% CaCl2. The liquid is brought into contact in counter-current with an organic solvent, n-butanol, in the column in the presence of the aqueous phase in the amount of 100 l/h and at a volume ratio O/A (organic phase/aqueous phase)=2. Phosphoric and hydrochloric acid passed into the solvent, and the most the most part of calcium chloride and impurities remained in the aqueous phase (the efficiency of extraction of R 2O5: 80%). The organic solvent content of HCl and H3PO4(composition: 10% N3PO4and 2.5% HCl, 0.8% CaCl2) resulted in a three-tiered extractor in contact with the fraction of the aqueous phosphate solution obtained at the following stage (composition: 30% N3PO4), with a volumetric ratio of O/A=6. During the operation of the organic solution were removed calcium chloride and impurities introduced during the extraction in the system "liquid-liquid", which has achieved high levels of purity. The washing liquor was returned to the head of the extraction column with an organic solvent. The efficiency of removal of calcium from the organic phase is very high: >99%.

The organic solution was washed with water in a countercurrent in megtalalhato column. Water extracted from the organic phase phosphoric and hydrochloric acids. After removal of the acid organic solvent can be re-used at the site of extraction. In addition, the phosphate solution is applied to the concentration.

Transaction performance: 80% re-extraction of R2O5. All these operations were carried out at ambient temperature.

Extracted dilute phosphate solution is evaporated to concentrate and removal by distillation of the residual traces of HCl and solvent.

1. the procedure of obtaining phosphoric acid, includes

at least disposable decomposition of phosphate ore first aqueous hydrochloric acid solution with a concentration of HCl not more than 10 wt.% with the formation of liquid decomposition product,

the first separation liquid decomposition product insoluble solid phase containing impurities and separate the aqueous phase content in the form of a solution of phosphate ions, chloride and calcium,

extraction of the aqueous solution with a content of phosphate ions, chloride and calcium organic extractant to obtain the extraction of the aqueous phase with a content of chloride ions and calcium and extraction of the organic phase with phosphoric acid,

re-extraction of the organic extraction phase water re-extractant for separation of the aqueous phase obtained by re-extraction and containing phosphate ions and, if necessary

concentrated re-extracted aqueous phase to obtain pure aqueous phosphate solution

characterized in that it additionally contains

neutralization of the aqueous phase separated from the liquid product of decomposition, the addition of calcium to education with the help of phosphate ions water-insoluble calcium phosphate, rolling in the sediment,

the second division neutralized in the ne phase to a water phase content in the form of a solution of calcium ions and chloride and the precipitated solid phase based on water-insoluble calcium phosphate,

dissolution (solubilization), at least part of the selected precipitated solid phase in the second aqueous hydrochloric acid solution which contains HCl in excess of its content in the first hydrochloric acid solution, with formation of an aqueous solution containing phosphate ions, chloride and calcium extractable organic extractant.

2. The method according to claim 1, characterized in that the first aqueous hydrochloric acid solution contains HCl in the amount of 3-6 wt.%, preferably 3-5 wt.%.

3. The method according to claim 1 or 2, characterized in that the molar ratio between HCl and CA in the liquid decomposition product is 0.6 to 1.3.

4. The method according to claim 1 or 2, characterized in that the stage of decomposition is carried out at ambient temperature.

5. The method according to claim 1 or 4, characterized in that the calcium compound for use on stage neutralization is selected from the group consisting of calcium hydroxide, calcium oxide and water-soluble calcium salts such as calcium carbonate, and that the water-insoluble calcium phosphate is monohydratefast calcium (DCP).

6. The method according to claim 1 or 2, characterized in that the selected precipitated solid phase on the basis of insoluble calcium phosphate contains 40-50 wt.% P2O5and 25-28 wt.% Sa.

7. The method according to claim 1 or 2, characterized in that the second aqueous hydrochloric acid solution contains Cl in an amount of from 15 to 20 wt.%.

8. The method according to claim 1 or 2, characterized in that the solubilized extracted aqueous solution contains P2O5in the amount of 8-15 wt.%, preferably 10-13 wt.%.

9. The method according to claim 1, characterized in that after the extraction of additional rinse extraction of the organic phase fraction of the aqueous phase, obtained by repeating the extraction, removal of the organic extraction phase of hydrochloric acid, captured her calcium chloride and possible residual impurities.

10. The method according to claim 1, characterized in that it further carry out the distillation with steam trace organic extractant from the aqueous extraction phase containing chlorine ions and calcium.

11. The method according to claim 9 or 10, characterized in that the concentration of P2About5in the aqueous phase, obtained by re-extraction and ion-containing phosphate is 15-25 wt.%.

12. The method according to claim 1 or 2, characterized in that the phosphate ore contains large grains, which are mostly 150-500 μm, and that the contents of P2O5reaches 15-38 wt.%.

13. The method according to claim 1 or 2, characterized in that additionally process the aqueous phase obtained in the second division and containing in solution the ions of calcium and chloride, aqueous sulfuric acid solution with the formation of precipitated insoluble is the Ulfat calcium and the aqueous phase on the basis of hydrochloric acid, separating the precipitate of calcium sulfate and at least partial recycling of the aqueous phase on the basis of hydrochloric acid to obtain the first and/or second aqueous hydrochloric acid solution.

14. The method of obtaining salt of phosphoric acid, comprising the following stages:

at least disposable decomposition of phosphate rock aqueous hydrochloric acid solution with a concentration of HCl not more than 10 wt.% with the formation of liquid decomposition product, in which the phosphate ore is dissolved in the form of phosphate ions,

the first separation liquid decomposition product insoluble solid phase and aqueous phase, while the solid phase separated from the decomposition product contains impurities, the aqueous phase separated from the decomposition product, it contains phosphate ions,

neutralization of selected aqueous phase and

the second division of the neutralized aqueous phase to the liquid phase and the solid product

characterized in that for obtaining monohydrogenphosphate calcium (DCP) molar ratio between HCl and CA in the liquid decomposition product is 0.6-1.3 and the above neutralization is performed by adding at least one calcium in the selected aqueous phase thereby to obtain an molar ratio of CA:P of order 1, 2, and the solid product of the second RA the division does not receive a water-soluble monohydratefast calcium.

15. The method according to 14, characterized in that the aqueous hydrochloric acid solution contains HCl in the amount of 3-6 wt.%, preferably 3-5 wt.%.

16. The method according to 14 or 15, characterized in that the stage of decomposition of the ore is carried out at ambient temperature.

17. The method according to 14 or 15, characterized in that the calcium compound for use on stage neutralization is selected from the group consisting of calcium hydroxide, calcium oxide and water-soluble calcium salts such as calcium carbonate.

18. The method according to 14 or 15, characterized in that the selected precipitated solid phase based on water-insoluble calcium phosphate contains 40-50 wt.% P2O5and 25-28 wt.% Sa.

19. The method according to 14 or 15, characterized in that it further includes processing the liquid phase obtained in the second division and containing in solution the ions of calcium and chloride, aqueous sulfuric acid solution with the formation of insoluble calcium sulfate, precipitated, and the aqueous phase on the basis of hydrochloric acid, separating the precipitate of calcium sulfate and at least partial recycling of the aqueous phase on the basis of hydrochloric acid to produce aqueous hydrochloric acid solution.

20. The method of obtaining phosphoric acid, comprising the following stages:

dissolution of the solid phase on the basis of water-insoluble phosphate calcev aqueous hydrochloric acid solution, which contains HCl in an amount of from 15 to 20 wt.% with the formation of an aqueous solution containing phosphate ions, chloride and calcium,

extraction solubilizing aqueous solution with an organic extractant to obtain the extraction of the aqueous phase containing chloride ions and calcium, and extraction of the organic phase containing phosphoric acid,

re-extraction of the organic extraction phase water re-extractant for separation of the aqueous phase obtained by re-extraction and ion-containing phosphate, and optional

concentrated aqueous phase, obtained by re-extraction, to obtain pure aqueous phosphate solution.

21. The method according to claim 20, characterized in that the extracted aqueous solution contains P2O5the number 10-13 wt.%.

22. The method according to claim 20, characterized in that it further includes, after the extraction stage leaching extraction of the organic phase fraction of the aqueous phase, obtained by repeating the extraction, removal of the extraction of the aqueous phase of hydrochloric acid, captured her calcium chloride and possible residual impurities.

23. The method according to item 22, wherein the aqueous phase, obtained by re-extraction, contains P2About5in the amount of 15-25 wt.%.

24. The method according to claim 20, distinguish the different topics what a solid phase on the basis of water-insoluble calcium phosphate is produced by the method according to any one of PP-19.



 

Same patents:

FIELD: inorganic compounds technologies.

SUBSTANCE: invention relates to purification of phosphoric acid containing considerable amount of magnesium ions, in particular phosphoric acid produced in chemicals plant "Belorechenski", with organic extractants. Specifically, phosphoric acid is extracted with tributyl phosphate by mixing organic and aqueous phases followed by further separation thereof to produce raffinate. Organic phase is re-extracted to produce purified phosphoric acid. Extraction is carried out in 4-5 steps while performing mixing in each step for 1.0-1.5 min.

EFFECT: enabled purification of phosphoric acid to low impurity level so that can be used to produce technical and food-grade phosphate salts.

1 tbl

FIELD: chemical industry; methods of purification of the extractive phosphoric acid.

SUBSTANCE: the invention is pertaining to the method of purification of the extractive phosphoric acid by the organic extractants and production of the phosphoric acid with the low content of impurities, that allows to use it in production of the phosphoric of the industrial and alimentary qualities. In particular, the invention is pertaining to purification of the extractive phosphoric acid containing the significant amount of ions of magnesium. The method includes extraction of the phosphoric acid by tributyl phosphate, washing of the produced extract by the phosphate solution and the subsequent reextraction with production of the reextract and after that its evaporation by the purified phosphoric acid. The extraction is conducted using 4-5 stages, and for washing they feed the phosphate solution in the amount providing the ratio P2O5:Mg in the extract equal to (5-8 : 1). As the phosphate solution of washing use either a part of the reextract, or the purified water diluted phosphoric acid. The technical result of the invention consists in purification of the phosphoric acid containing a significant amount of magnesium, at simultaneous increase of extraction of P2О5.

EFFECT: the invention ensures purification of the phosphoric acid containing a significant amount of magnesium, at simultaneous increase of extraction of P2О5.

2 cl, 1 ex

FIELD: inorganic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing phosphoric acid with low content of impurities and used in producing phosphate salts of technical and nutrition quality by using liquid extraction with tributyl phosphate and the following separation of an aqueous and organic phases and re-extraction of phosphoric acid from organic phase with water. Extraction and re-extraction are carried out in pulsation columns by mixing aqueous and organic phases to form emulsion under air effect at the extraction temperature 30-50°C and the re-extraction temperature 40-80°C followed by separation of the re-extraction process for some steps. At the first step the preliminary washed out extract is prepared and then it is fed to the step for preparing purified phosphoric acid and polluted acid recovered to the stage for extraction with tributyl phosphate. The total water flow feeding to the re-extraction step is divided for three parts in the following ratio: V1:(V2 + V3) = 1:(2.5-10) and (V2 : V3) = 1:(1-2.5). Extract is mixed with the first part of water and after separating phases is fed successively to mixing with other part and then with the third part of water for preparing purified and highly purified phosphoric acids. Mixing the first part of water with extract is carried out in the volume ratio of phases = 1:(20-55), and mixing the second and third part of water with extract is carried out in the ratio = 1:(5-20). Proposed method provides decreasing the content of impurities in highly purified phosphoric acid preparing at the third step of re-extraction by 2-fold, i. e. to enhance quality of acid.

EFFECT: improved treatment method of phosphoric acid.

7 cl, 2 tbl, 2 ex

FIELD: technology of restoration of extracting agent in the course of cleaning extraction phosphoric acid obtained by sulfuric acid decomposition of natural phosphates by means of liquid extraction with tributyl phosphate followed by separation of aqueous and organic phases and re-extraction of phosphoric acid from organic phase by means of water.

SUBSTANCE: extraction and re-extraction are performed in pulsation columns by mixing the aqueous and organic phases for forming emulsion under action of air at extraction temperature of 30-50°C and re-extraction temperature of 40-80°C during process of mixing with water and organic phases for forming emulsion under action of air in pulsation mode when part of circulating extracting agent is separated for washing with alkaline solution and water followed by returning it to extraction stage; aqueous phase which is just alkaline solution is treated with phosphoric acid at concentration of 20-54% and volume ratio of Valk. : (V1 + V2) = (0.4-2.5) : 1 at 10-60°C in two stages in succession separating the phosphoric acid flow in volume ratio of V1:V2 = 1: (0.5-13) obtaining salt solution at pH of 4-7 at 1st stage, pH of 1-3 at 2nd stage followed by separation of gummy agents at 1st stage, settling and decanting and filtration at 2nd stage.

EFFECT: reduced losses of extracting agent; enhanced purity of phosphoric acid salts.

3 cl, 1 tbl, 1 ex

The invention relates to a method for producing phosphoric acid with a low content of impurities, used in the production of phosphate salts technical and food skills

The invention relates to a method for producing phosphoric acid with a low content of impurities, used in the production of phosphate salts technical and food skills using solvent extraction with tributyl phosphate with subsequent separation of the aqueous and organic phases and reextracting phosphoric acid from the organic phase with water

The invention relates to the production of purified phosphoric acid from wet-process phosphoric acid (EPA) by treating it with an organic solvent, mostly not miscible with the acid

The invention relates to the production of purified phosphoric acid from wet-process phosphoric acid (EPA) by treating it with an organic solvent, mostly not miscible with the acid
The invention relates to a technology for purifying phosphoric acid, sulfuric acid obtained by decomposition of natural phosphates using solvent extraction with tributyl phosphate with subsequent separation of the aqueous and organic phases and reextracting phosphoric acid from the organic phase with water

The invention relates to the production of mineral fertilizers, food phosphates, chemicals and detergents on the basis of the processing of phosphate minerals, in particular to a method of processing wet-process phosphoric acid for its extraction and purification from impurities

FIELD: inorganic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for preparing fodder calcium phosphates, namely to producing monocalcium phosphate. Method involves mixing wet-process phosphoric acid with a calcium-containing component in the presence of recycle, granulation and drying the product. Mixing process is carried out for two stages. At the first stage wet-process phosphoric acid with the concentration 62-65% of P2O5 is fed and process is carried out at recycle index = 1:(0.3-0.5) up to decomposition degree of calcium-containing raw = 0.89-0.92 at this stage. The second stage is combined with granulation and carried out its in high-speed mixer in water addition to obtain moisture in mixture 9.5-13%. The rate and time for mixing are regulated to provide the decomposition degree of calcium-containing raw = 0.93-0.99, and temperature at the next drying stage is maintained in the level 105-115°C. Method provides simplifying the process, reducing energy consumption and preparing product with the high content of P2O5 in water-soluble form and low content of fluorine.

EFFECT: improved method for preparing.

2 cl, 3 ex

FIELD: industrial inorganic synthesis.

SUBSTANCE: monocalcium phosphate, widely applied in agriculture, is prepared by mixing extraction phosphoric acid with calcium-containing component followed by granulation and drying of product. During mixing of components, appropriate temperature and moisture are maintained to ensure viscosity of mixture 3-7 mPa*s, and granulation and drying are carried out simultaneously in drum-type granulator drier. Calcium-containing component is either calcium carbonate or mixture thereof with limestone, whose does not exceed 15% of total weight of calcium-containing raw material. Moisture content in worked out drying agent leaving drum-type granulator drier equals 70-80 g per 1 kg dry air.

EFFECT: simplified process flowsheet, enabled granule size control, and increased strength of granules.

3 cl, 3 ex

The invention relates to the technology of production of fine high-purity calcium hydroxyapatite (microgranules), which can be used in the manufacture of composite materials, bioceramics, materials, stimulating regeneration of the bone tissue, the pharmaceutical carrier

The invention relates to a method of obtaining high temperature protonotaria double phosphates of calcium with iron and copper, which can be used as fuel cells, materials for the two-stage oxidation of fuel, gas sensors and catalysts
The invention relates to the production of phosphate salts of magnesium, particularly to a method of obtaining high-water translesanas phosphate magnesium [Mg3(PO4)2nH2O] suitable for use as hydrated on the units for production of desalinated water, and it may also find application as catalysts, adsorbents and light fillers
The invention relates to the processing of natural phosphate Apatite, and in particular to methods of decomposition of the complex fluoride raw material - fluorapatite, and can be used to obtain metaphosphoric acid and hydrogen fluoride used in the chemical industry, and calcium sulphate (anhydrite), used in the manufacture of building materials

The invention relates to the production of calcium phosphates, in particular calcium orthophosphate one-deputizing used in the food industry
The invention relates to the production of pure salts of calcium phosphate and can be used in the manufacture of composite materials, bioceramics, sorbents and catalysts

The invention relates to techniques for processing wet-process phosphoric acid technical phosphates, in particular fodder dicalcium phosphate, using waste

The invention relates to a method for producing fine high purity hydroxyapatite (MHA), which can be used for the production of medical materials, stimulating regeneration of bone defects, manufacturing, dental fillings, tooth pastes, sorbents, etc
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