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CN100339299C - Method for purification of phosphoric acid - Google Patents

Method for purification of phosphoric acid Download PDF

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CN100339299C
CN100339299C CNB2005101136508A CN200510113650A CN100339299C CN 100339299 C CN100339299 C CN 100339299C CN B2005101136508 A CNB2005101136508 A CN B2005101136508A CN 200510113650 A CN200510113650 A CN 200510113650A CN 100339299 C CN100339299 C CN 100339299C
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phosphoric acid
arsenic
content
acid
hydrogen halide
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CN1817790A (en
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堀田清史
久保田冬彦
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Toyobo Co Ltd
Toyo Textile Co Ltd
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Toyo Textile Co Ltd
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Abstract

A method for purification of phosphoric acid, characterized as comprising contacting a crude phosphoric acid containing arsenic with hydrogen halide to remove the arsenic from the crude phosphoric acid; and a method for purification of phosphoric acid, characterized as comprising contacting a crude phosphoric acid containing arsenic with hydrogen halide in the presence of a compound which can produce hydrogen halide under an acidic condition. The above methods provide novel methods for removing arsenic from a crude phosphoric acid which does not require any of a filtering and a degassing processes which are necessary in the sulfide precipitation method, does not give a large amount of residual sodium, can be applied to a crude phosphoric acid having a high concentration of phosphorus pentoxide, particularly to polyphosphoric acid, and can be practiced at a low cost; and thus they can be used for producing a high purity polyphosphoric acid having an arsenic (As) content of 1 ppm or less and also low contents of heavy metals, silica, sodium and the like.

Description

The method of purification of phosphoric acid
The application is Chinese patent application 99815152.1 (applying date 1999.12.24; Priority date 1998.12.28,1999.8.17, international application no PCT/JP99/07312, exercise question are " method of purification of phosphoric acid and high purity polyphosphoric acid ") divide an application.
Technical field
The present invention relates to the method for purification of phosphoric acid, this method can reduce the content of harmful heavy metal, particularly arsenic effectively, and relates to the high purity polyphosphoric acid that obtains thus, and it is expected at food, and medicine and field of electronic materials are used widely.
Background technology
Produce the method for phosphoric acid, known have wet method and dry method, and one of industrial these methods of employing are produced phosphoric acid.In wet method, Rock Phosphate (72Min BPL) is dissolved in the sulfuric acid, filter out the gypsum composition, obtain the dilute phosphoric acid of lower concentration, and dilute phosphoric acid is concentrated to required level, obtain phosphoric acid.In dry method, Rock Phosphate (72Min BPL) is reduced in electric furnace, obtain yellow phosphorus, its burning obtains phosphoric anhydride, then the phosphoric anhydride hydration is obtained phosphoric acid.Usually, wet method does not need reduction or burning, and it is favourable being considered to aspect production cost.Dry method has reduced the pollution from the impurity of Rock Phosphate (72Min BPL) because produce via phosphoric anhydride, and it is favourable being considered to aspect quality.Yet, in any production method, all containing arsenic in the phosphoric acid that obtains from Rock Phosphate (72Min BPL) or phosphoric anhydride, it is deleterious to human body, is about tens ppm usually, carries out dearsenification according to the purposes employing sulfide agglomerative method of phosphoric acid.Conventional arsenic removing method only is applicable to P 2O 5Concentration is up to about 60% phosphoric acid.
High concentrations of phosphoric acid, particularly Tripyrophosphoric acid (P 2O 5Concentration is not less than 72.4%), as phosphoric acid, also adopt aforesaid wet method or dry production.With the Tripyrophosphoric acid of dry production,, demonstrate lower heavy metal usually, silicon-dioxide and sodium content owing to produce via phosphoric anhydride.Yet because conventional arsenic removing method is not suitable for high concentrations of phosphoric acid, it contains the arsenic from phosphoric anhydride of the 5-100ppm that has an appointment.Tripyrophosphoric acid with wet production demonstrates the low arsenic content that is lower than 1ppm, because can use conventional arsenic removing method before concentrating.On the other hand, demonstrate to its characteristic the high-load heavy metal that derives from Rock Phosphate (72Min BPL), silicon-dioxide and sodium.High concentrations of phosphoric acid, particularly Tripyrophosphoric acid is characterized in that demonstrating low arsenic content and low heavy metal, and silicon-dioxide and sodium content also do not obtain.
As the P that obtains with dry method 2O 5Concentration is up to about 60% phosphoric acid, and when carrying out dearsenification and handle and concentrate with conventional sulfide coagulation method etc., estimation can obtain having the arsenic of low levels, heavy metal, the phosphoric acid of silicon-dioxide and sodium.Yet this production method also is not applied in the practice.This is that this is extremely disadvantageous from economic point of view, because equipment cost and operating cost are all high because need be used to burn and the device of hydration yellow phosphorus and be used for highly concentrating the device of gained phosphoric acid.
The arsenic that in phosphoric acid and Tripyrophosphoric acid, contains, at food, medicine, the highly purified Application for Field of needs such as electronic material is disadvantageous especially.And recent years has been owing to given great attention to environmental problem, need have the phosphoric acid of low arsenic content and Tripyrophosphoric acid as industrialization phosphoric acid, is used for metal finishing, dyestuff processing etc.Therefore, need a kind of arsenic removing method that can effectively turn round with low cost.
Known from phosphoric acid the method for dearsenification comprise: (1) sulfide coagulation, (2) solvent extration and (3) ion exchange method.Wherein the sulfide coagulation is the most general, because required step and equipment are simpler, and this method operating cost is low.This method comprises makes phosphoric acid and hydrogen sulfide, or is dissolved in the sodium sulphite that can produce hydrogen sulfide in the phosphoric acid, and contacts such as Sodium sulfhydrate make the form precipitation of arsenic with arsenic sulfide, separate subsequently and remove.On the contrary, solvent extration and ion exchange method are not too general, because step and equipment complexity, and cost is higher.
Yet the sulfide coagulation also needs filtration unit, vacuum filter for example, pressure filter, centrifuge separator etc.The arsenic sulfide that precipitates tends to form colloid, causes to be difficult to separate and to be difficult to remove arsenic from phosphoric acid.Comprise process activated carbon tower route method (Japanese kokai publication hei 6-48712 communique) and comprise the method (Japanese kokai publication hei 6-100307 communique) that adds resin for ease of separating, having used.These methods are not preferred method, because equipment and processing cost are higher.
And when residual when hydrogen sulfide is arranged in the phosphoric acid, the corrodibility of phosphoric acid strengthens, thereby need slough excessive hydrogen sulfide with air and nitrogen, causes step complicated.When using, during compounds such as Sodium sulfhydrate, in sodium content very important use, can not use this method, because sodium remains in the phosphoric acid in a large number such as sodium sulphite.
When using the sulfide coagulation, when phosphoric acid concentration was higher, particularly under the Tripyrophosphoric acid situation, phosphoric acid itself reached higher viscosity, separated therefore that to remove arsenic sulfide more difficult.Therefore, this method is applicable to P 2O 5The highest 60% the phosphoric acid that is about of concentration.
The method of dearsenification from high-concentration phosphoric acid, Japanese Patent Publication 53-128595 communique disclose the method for wet technique refinement phosphoric acid.According to this method, to P 2O 5Concentration is up in about 82% the phosphoric acid and adds sodium-chlor, makes arsenic and chlorine reaction in the phosphoric acid to separate and to remove.Because this method comprises the sodium-chlor that uses 1000-2000ppm, remaining in the phosphoric acid after dearsenification have a large amount of sodium.
The general arsenic removing method step of need filtering and outgas, this two step is all costly, and remaining in phosphoric acid a large amount of sodium is arranged.They can not be used for P 2O 5Concentration is not less than in 60% the high-concentration phosphoric acid, particularly in the Tripyrophosphoric acid.In addition, also can't obtain having low arsenic, heavy metal, the high-concentration phosphoric acid of silicon-dioxide and sodium content, particularly Tripyrophosphoric acid by practicable low cost method.Therefore, the Application Areas of Tripyrophosphoric acid do not need to be confined to highly purified field.
The invention provides a kind of method of dearsenification from phosphoric acid completely newly, its operating cost is low, and is different with the sulfide coagulation, and it does not need to filter and degassing step, does not have a large amount of remaining sodium, and this method is applicable to high-concentration phosphoric acid, particularly Tripyrophosphoric acid.Also have, the objective of the invention is to obtain having low arsenic, heavy metal, the high purity polyphosphoric acid of silicon-dioxide and sodium content, it can not obtain with ordinary method.
Disclosure of the Invention
The present inventor has carried out intensive research for addressing the above problem, and finds that in the organic synthesis process of the association hydrogenchloride that carries out in high-concentration phosphoric acid, the arsenic content of phosphoric acid obviously reduces.It further be studies show that, this organic synthesis itself does not matter with the dearsenification effect, but by phosphoric acid is contacted with hydrogen halide, the arsenic content of phosphoric acid can be reduced to and be no more than about 1ppm, also finds, when contact is to be that there be following carrying out in the compound that can form hydrogen halide under the acidic conditions, the dearsenification effect improves, and this method is for dearsenification, and particularly dearsenification is that effectively this is accomplished the present invention from Tripyrophosphoric acid.
Therefore, the invention provides:
(1) method of purification of phosphoric acid, this method comprise makes arsenical phosphoric acid contact with hydrogen halide, dearsenification from phosphoric acid thus.
(2) process for purification of above-mentioned (1) wherein makes arsenical phosphoric acid be that the compound existence that can form hydrogen halide under the acidic conditions contacts with hydrogen halide down.
(3) process for purification of above-mentioned (2) wherein can form the compound of hydrogen halide under acidic conditions, be to add with the ratio that is lower than phosphoric acid weight 1%.
(4) process for purification of above-mentioned (2) wherein can form the compound of hydrogen halide under acidic conditions, be iron (II) muriate of copper (I) or tin (II).
(5) process for purification of above-mentioned (1), wherein hydrogen halide is a hydrogenchloride.
(6) process for purification of above-mentioned (1), wherein phosphoric acid has and is not less than 72.4% P 2O 5Concentration.
(7) highly purified Tripyrophosphoric acid, its iron (Fe) content is no more than 20ppm, and sodium (Na) content is no more than 100ppm, silicon-dioxide (SiO 2) content is no more than 50ppm, and arsenic (As) content is no more than 1ppm.
(8) high purity polyphosphoric acid of above-mentioned (7), wherein iron (Fe) content is no more than 10ppm, and sodium (Na) content is no more than 5ppm, silicon-dioxide (SiO 2) content is no more than 5ppm, and arsenic (As) content is no more than 1ppm.
(9) high purity polyphosphoric acid of above-mentioned (7), its chromium (Cr) content is no more than 5ppm, and nickel (Ni) content is no more than 5ppm, and molybdenum (Mo) content is no more than 5ppm.
(10) high purity polyphosphoric acid of above-mentioned (8), wherein chromium (Cr) content is no more than 2ppm, and nickel (Ni) content is no more than 2ppm, and molybdenum (Mo) content is no more than 2ppm.
Before the present invention is described in detail, as follows to the representation specification of phosphoric acid concentration.
In the present invention, phosphoric acid is ortho-phosphoric polycondensation product, and its concentration transforms back or P with ortho-phosphoric acid usually 2O 5Concentration after the conversion is represented.Ortho-phosphoric acid concentration is 100% phosphoric acid, is equivalent to P 2O 5Concentration is 72.4% phosphoric acid, and wherein the relation between two concentration is represented with following equation:
P 2O 5Concentration (%)=ortho-phosphoric acid concentration (%) * 0.724
P 2O 5Concentration is lower than 72.4% phosphoric acid, is phosphate aqueous solution, contains ortho-phosphoric acid polycondensation product and water under equilibrium state.P 2O 5Concentration is not less than 72.4% phosphoric acid, only is made up of the ortho-phosphoric acid polycondensation product, is called Tripyrophosphoric acid, strong phosphoric acid or super phosphoric acid.In the present invention, phosphoric acid concentration P 2O 5Concentration is represented.
In first embodiment of purification of phosphoric acid method according to the present invention, arsenical phosphoric acid is contacted, dearsenification from phosphoric acid separately with hydrogen halide.Reason that in this way can dearsenification is also uncertain, but changing into the arsenic in the phosphoric acid, the supposition hydrogen halide has high-volatile arsenic compound, for example arsonium halide and arsonium, this compound evaporates under the treatment temp of process for purification of the present invention, and emits with hydrogen halide from system.At present also do not know the chemical state of arsenic in phosphoric acid, but think that arsenic is with arsenic acid, arsenus acid, arsenic powder, forms such as white arsenic exist.
Although there is no particular limitation to being applied to phosphoric acid concentration in first embodiment, when this method was used for lower concentration phosphoric acid, hydrogen halide can be dissolved in the water, had increased the corrodibility of phosphoric acid, and it is residual to cause handling the back hydrogen halide.Therefore, to be used for the phosphoric acid of water-content relatively low (high phosphoric acid concentration) be favourable to this method.Especially, when it was used for complete anhydrous Tripyrophosphoric acid, hydrogen halide can not remain in the Tripyrophosphoric acid, can eliminate corrodibility like this.When the phosphoric acid that uses during as Tripyrophosphoric acid, preferred concentration range is the scope that does not have freezing point, i.e. P 2O 5Concentration is 75-77% or is not less than 80%.Consider operability, P 2O 5The upper limit of concentration is preferably 90%.
In second embodiment of purification of phosphoric acid method of the present invention, be that the compound that can generate hydrogen halide under the acidic conditions exists down, makes arsenical phosphoric acid contact with hydrogen halide, dearsenification from phosphoric acid.In this embodiment, dearsenification efficiently.The compound that can generate hydrogen halide under acidic conditions can be the organic or inorganic compound.Especially, it preferably has the metal halide of reductive action, more preferably iron (II), the halogenide of copper (I) or tin (II), the muriate of these metals most preferably, preferred especially iron (II), or the muriate of tin (II).
When arsenical phosphoric acid under acidic conditions, can generate hydrogen halide compound in the presence of when contacting with hydrogen halide, reason owing to the unknown, promoted the dearsenification effect, but supposition arsenic itself becomes and is easy to reduction and becomes volatile arsenic compound easily, for example arsonium halide and arsonium, it is easy to evaporation under the treatment temp of process for purification of the present invention, because when adding particular significant effect during as the metal halide of reductive agent.
In second embodiment, add the compound that under acidic conditions, can generate hydrogen halide of trace, its consumption preferably is lower than the 1wt% of phosphoric acid weight, more preferably less than 0.5wt%.When using this compound with greater amount, the dearsenification effect in theory can be better.But when this compound was metal halide especially, the impurity of metal was worthless in the metal halide in remaining deriving from.When needs are avoided remaining impurity, maybe when needing highly purified phosphoric acid, during particularly highly purified Tripyrophosphoric acid, first embodiment that wherein arsenical phosphoric acid only contacts with hydrogen halide than second embodiment more preferably.
In first and second embodiment, phosphoric acid contacts in any typical solution-air mixing device with hydrogen halide, and described device can be step or continous way.For example, can use and a kind ofly wherein use batch reactor, and vigorous stirring phosphoric acid and the method that directly blasts hydrogen halide wherein, a kind of static mixer or injector of wherein using, and the method for continuous mixed phosphate and hydrogen halide, and a kind of method that is used in combination above-mentioned two kinds of methods etc.The hydrogen halide of Shi Yonging can be a hydrogenchloride in the present invention, and hydrogen bromide etc. preferably use hydrogenchloride, because it can obtain the easyliest and most economical.
In first and second embodiment, greatly depend on the solution-air mixing efficiency of equipment therefor with respect to the requirement of the hydrogen halide of phosphoric acid, and be difficult to stipulate the scope of this amount.Because it is tervalent or pentavalent that the arsenic in phosphoric acid is considered to, with respect to arsenic content, the hydrogen halide that is not less than 3 molar equivalents at least is considered to essential.Using batch reactor, and vigorous stirring phosphoric acid with directly blast under the simplest method situation of hydrogen halide wherein, for example, hydrogenchloride is blasted the 500ml Tripyrophosphoric acid (P that arsenic content is 50ppm 2O 5Concentration is 85%) in speed, be preferably 1~100ml/min, 10~80ml/min more preferably, the time that blasts preferably is not less than 30min, more preferably is not less than 60min.
In first and second embodiment, treatment temp changes according to the material of concentration of phosphoric acid and reactor, but can be the arbitrary values in about 50~200 ℃ of scopes.Consider the corrodibility of phosphoric acid, wish that treatment temp is no more than 150 ℃ industrial stainless material as reactor etc.For the evaporation of the arsenic compound that promote to generate, wish that treatment temp is at least 50 ℃, more preferably is not less than 100 ℃.There is no particular limitation to pressure, can set arbitrarily, wherein just can reach enough dearsenification effects under normal pressure.
And in first and second embodiment, arsenic compound is emitted from system with hydrogen halide.These compounds preferably water absorb and neutralization, or use sodium hydroxide, and the alkaline aqueous solution of potassium hydroxide etc. absorbs.
According to the method for purification of phosphoric acid of the present invention, can obtain having the phosphoric acid of the low arsenic content that is no more than about 1ppm with simple method.Particularly, when being to generate this method of the following use of compound existence of hydrogen halide under the acidic conditions, can obtain having the phosphoric acid of the low arsenic content that is no more than about 0.1ppm.Because this method does not need the equipment cost of filtration step or degassing step, or uses sodium compound, sodium sulphite for example, Sodium sulfhydrate etc., therefore different with method in common, this method is can be in phosphoric acid remaining a large amount of sodium.Have a low heavy metal by process for purification of the present invention being applied to, in the phosphoric acid of sodium and dioxide-containing silica, can obtain having low arsenic content and low heavy metal, the phosphoric acid of silicon-dioxide and sodium content with what dry method obtained.
The method of purification of phosphoric acid of the present invention does not need conventional filtration step.Therefore, this method is applicable to high-concentration phosphoric acid, particularly Tripyrophosphoric acid.Has a low heavy metal by process for purification of the present invention being applied to what dry method obtained, silicon-dioxide and sodium content, but have in the Tripyrophosphoric acid of high arsenic content, the low arsenic content that has that can't obtain before this can be provided, and low heavy metal, the high purity polyphosphoric acid of silicon-dioxide and sodium content.
Particularly, by process for purification of the present invention is applied to phosphoric anhydride is joined industrial phosphoric acid, and be dissolved in wherein and in the Tripyrophosphoric acid of preparation, can obtain iron (Fe) content and be no more than 20ppm, sodium (Na) content is no more than 100ppm, silicon-dioxide (SiO 2) content is no more than 50ppm, arsenic (As) content is no more than 1ppm, and chromium (Cr) content is no more than 5ppm, and nickel (Ni) content is no more than 5ppm, and molybdenum (Mo) content is no more than the Tripyrophosphoric acid of 5ppm.
By process for purification of the present invention is applied in the Tripyrophosphoric acid, this Tripyrophosphoric acid is by phosphoric anhydride being joined in the phosphoric acid or the phosphoric acid as foodstuff additive as reagent, and be dissolved in wherein and preparation, can obtain iron (Fe) content and be no more than 10ppm, sodium (Na) content is no more than 5ppm, silicon-dioxide (SiO 2) content is no more than 5ppm, arsenic (As) content is no more than 1ppm, and chromium (Cr) content is no more than 2ppm, and nickel (Ni) content is no more than 2ppm, and molybdenum (Mo) content is no more than the Tripyrophosphoric acid of 2ppm.
Adopt following method to measure the content of various elements in the Tripyrophosphoric acid in the present invention.
Measure arsenic according to JIS-K 0102 (1993) method.Because think in the Tripyrophosphoric acid sample, not have organic substance, so omitted disclosed step in JIS with sulfuric acid/nitric acid decomposing organic matter matter.Adopt inductively coupled plasma (ICP) analytical method to come quantitative assay iron, chromium, nickel, molybdenum and silicon-dioxide.By in Tripyrophosphoric acid, adding hydrochloric acid, make the hydrochloric acid soln of 1.2M, prepare the ICP sample solution.Regulate the calibration curve of phosphoric acid solution, make its concentration identical with sample solution.Adopt atomic absorption spectrum quantitative assay sodium.The sample solution of atomic absorption be used for the identical of ICP.Measure P in the Tripyrophosphoric acid by using the titration of 1M sodium hydroxide solution 2O 5Concentration.
The present invention will be described in more detail below with reference to embodiment.The present invention is not limited to these embodiment.
Embodiment 1
The arsenic content that obtains with dry method that is purchased 130 ℃ of heated and stirred is Tripyrophosphoric acid (500ml, the P of 58ppm 2O 5Concentration is 84.9%), insert Glass tubing therebetween, and blast the about 2h of hydrogen chloride gas with the inflation rate of 20ml/min with the bowl-shape strainer of glass, obtain highly purified Tripyrophosphoric acid.In aqueous sodium hydroxide solution, catch the hydrogen chloride gas of emitting.The analytical results of the high purity polyphosphoric acid that obtains is listed in the table 1.
Embodiment 2
With the arsenic content that obtains with dry method that is purchased is Tripyrophosphoric acid (500ml, the P of 8ppm 2O 5Concentration is 84.2%), be injected in 1 liter of three mouthfuls of glass flask, and, insert Glass tubing therebetween, and blast the about 2h of hydrogen chloride gas with the inflation rate of 50ml/min with the bowl-shape strainer of glass 150 ℃ of heated and stirred, obtain highly purified Tripyrophosphoric acid.In aqueous sodium hydroxide solution, catch the hydrogen chloride gas of emitting.The analytical results of the high purity polyphosphoric acid that obtains is listed in the table 1.
Embodiment 3
Be that the phosphoric anhydride (200g) of 25ppm joins as the arsenic content of reagent with arsenic content be phosphoric acid (422g, the P of 0.1ppm 2O 5Concentration is 61.5%) in.This mixture obtains uniform liquid 120 ℃ of heated and stirred, and preparing arsenic content thus is the Tripyrophosphoric acid (P of 8ppm 2O 5Concentration is 84.0%).Under 150 ℃ of heated and stirred situations, insert Glass tubing, and blast the about 3h of hydrogen chloride gas with the inflation rate of 20ml/min with the bowl-shape strainer of glass, obtain highly purified Tripyrophosphoric acid.In aqueous sodium hydroxide solution, catch the hydrogen chloride gas of emitting.The analytical results of the high purity polyphosphoric acid that obtains is listed in the table 1.
Embodiment 4
With arsenic content is the phosphoric anhydride (170g) of 25ppm, and joining the arsenic content that obtains with dry method that is purchased is Tripyrophosphoric acid (330g, the P of 5ppm 2O 5Concentration is 76.0%) in.This mixture obtains uniform liquid 120 ℃ of heated and stirred, and preparing arsenic content thus is the Tripyrophosphoric acid (P of 11ppm 2O 5Concentration is 84.2%).Under 150 ℃ of heated and stirred situations, insert Glass tubing, and blast the about 3h of hydrogen chloride gas with the inflation rate of 20ml/min with the bowl-shape strainer of glass, obtain highly purified Tripyrophosphoric acid.In aqueous sodium hydroxide solution, catch the hydrogen chloride gas of emitting.The analytical results of the high purity polyphosphoric acid that obtains is listed in the table 1.
Embodiment 5
With arsenic content is industrial phosphoric acid (500ml, the P of 15ppm 2O 5Concentration is 65%), be injected in 1 liter of three mouthfuls of glass flask, and, insert Glass tubing therebetween, and blast hydrogen chloride gas with the inflation rate of 50ml/min with the bowl-shape strainer of glass 130 ℃ of heated and stirred.In aqueous sodium hydroxide solution, catch the hydrogen chloride gas of emitting.As a result, began back 180 minutes in air-blowing, the arsenic concentration in the phosphoric acid is 0.8ppm.
Embodiment 6
Use the treatment process identical, just before blasting hydrogen chloride gas, add iron(ic) chloride (II) (0.1g) with embodiment 5.As a result, began back 120 minutes in air-blowing, the arsenic concentration in the phosphoric acid is 0.07ppm.
Embodiment 7
Use the treatment process identical with embodiment 5, just adding two hydration tin chlorides (II) are (0.5g) before blasting hydrogen chloride gas.As a result, began back 120 minutes in air-blowing, the arsenic concentration in the phosphoric acid is 0.08ppm.
The analytical results of the every kind of element that contains in the high purity polyphosphoric acid that obtains in embodiment 1-4 is listed in the table 1.In order to compare, the analytical results of Tripyrophosphoric acid product A that obtains with dry method that is purchased and the Tripyrophosphoric acid product B that obtains with wet method that is purchased is also listed in the table 1.
Table 1
Analysis project Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 The product A that is purchased The product B that is purchased
P 2O 5Concentration (%) 84.9 84.2 84.0 84.2 85.0 84.3
Fe content 1.6 1.0 0.2 1.2 1.6 37
Cr content 0.8 0.1 0.1 0.7 0.8 6.3
Ni content 0.6 0.3 0.1 0.4 0.6 4.4
Mo content <0.5 <0.5 <0.5 <0.5 <0.5 12
Na content 0.1 0.1 0.1 0.1 0.2 250
SiO 2Content <5 <5 <5 <5 <5 120
As content 0.5 0.08 0.03 0.03 58 0.02
In table 1, each content unit is ppm.
Can find out obviously that from table 1 product A that is purchased (Tripyrophosphoric acid that obtains with dry method) demonstrates low heavy metal, silicon-dioxide and sodium content, but high arsenic content, and the product B that is purchased (Tripyrophosphoric acid that obtains with wet method) demonstrates low arsenic content, but high heavy metal, sodium and dioxide-containing silica.On the contrary, the high purity polyphosphoric acid of embodiment 1-4 demonstrates low arsenic content and low heavy metal, sodium and dioxide-containing silica.Can obviously find out from embodiment 6 and 7, when arsenical phosphoric acid is can generate under the acidic conditions compound of hydrogen halide, iron(ic) chloride (II) for example, tin chlorides (II) etc. exist down, contact with hydrogen halide, can improve the effect that removes the arsenic in the phosphoric acid.
Can find out obviously that from above-mentioned explanation adopt the simple operation that phosphoric acid is contacted with hydrogen halide, the method for purification of phosphoric acid of the present invention can remove arsenic harmful in the phosphoric acid effectively.Particularly, the arsenic content of tens ppm of general industrial phosphoric acid can drop to and be no more than about 1ppm.When being to generate the following use of the compound existence above-mentioned steps of hydrogen halide under the acidic conditions, can reach the level that removes that is no more than about 0.1ppm.
Described method comprises simple treatment step, and does not need special device.As a result, the total cost of processing is lower, and different with the method for routine, owing to do not use sodium compound, and can abundant residues sodium in phosphoric acid.
And different with the process for purification of routine, because the method for purification of phosphoric acid of the present invention does not need filtration step, it can be used for high-concentration phosphoric acid, particularly in the Tripyrophosphoric acid.Especially, to obtain with dry method, and has a low heavy metal, sodium and dioxide-containing silica, but the Tripyrophosphoric acid of high arsenic content is refining with method of the present invention, can obtain having low arsenic content and low heavy metal, the high purity polyphosphoric acid of silicon-dioxide and sodium content, this can't obtain before being.This high purity polyphosphoric acid is a high safety, and can alleviate the load of environment.Therefore, can be at food, use widely in fields such as medicine and electronic material.
The application is based on the patent application Nos.373696/1998 and 230628/1999 that submits in Japan, and its content is incorporated herein by reference.

Claims (6)

1. the method for a purification of phosphoric acid comprises hydrogen halide is blasted in the arsenical phosphoric acid, and wherein, with respect to arsenic content, the amount of blasting of hydrogen halide is not less than 3 molar equivalents, dearsenification from phosphoric acid thus.
2. the process of claim 1 wherein that described hydrogen halide is to blast in the presence of the compound that forms hydrogen halide under the acidic conditions.
3. the method for claim 2, the wherein said content that can form the compound of hydrogen halide under acidic conditions is lower than the 1wt% of phosphoric acid weight.
4. claim 2 or 3 method, the wherein said compound that can form hydrogen halide under acidic conditions is iron (II), the muriate of copper (I) or tin (II).
5. each method among the claim 1-3, wherein said hydrogen halide is a hydrogenchloride.
6. each method among the claim 1-3, the P of wherein said phosphoric acid 2O 5Concentration is not less than 72.4%.
CNB2005101136508A 1998-12-28 1999-12-24 Method for purification of phosphoric acid Expired - Fee Related CN100339299C (en)

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CN111217345A (en) * 2020-02-28 2020-06-02 成都易态科技有限公司 Yellow phosphorus furnace gas preparation device, yellow phosphorus condensation system and yellow phosphorus furnace gas preparation method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044108A (en) * 1976-02-13 1977-08-23 Toyo Soda Manufacturing Co., Ltd. Process for removing organic material from wet process phosphoric acid
US5246681A (en) * 1991-10-11 1993-09-21 Enichem Agricoltura S.P.A. Process for the removal of cadmium from solutions of phosphoric acid

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