CN102252980B - Direct determination U, HNO3、HNO2Method for mixing component concentrations - Google Patents

Abstract

The invention belongs to the technical field of spectral analysis and determination, and particularly relates to direct determination U, HNO₃、HNO₂Method of mixing concentrations of components. The method comprises the following steps: a) preparing m water phase and organic phase standard samples with different concentrations; b) measuring absorbance; c) selecting the peak and trough positions on the second order differential spectrum of the sample absorption spectrum as representative wavelength positions, and determining the absorbance values, U concentrations and HNO values of the m water phase standard samples at the wavelength positions₃Concentration and HNO₂Solving coefficient F by substituting concentration into formula₁、F₂、F₃. And for the unknown organic phase sample, measuring the absorption spectrum of each solution at 350-500 nm. Substituting the coefficient F in the range of 400-500 nm, solving the U concentration by using a formula , substituting the solved coefficient F in the range of 350-400 nm, and solving the HNO by solving the equation by using a formula (4)₂And (4) concentration.

Description

Directly measure U, HNO 3, HNO 2The method of blending ingredients concentration

Technical field

The invention belongs to spectral analysis determination techniques field, be specifically related to a kind of direct mensuration U, HNO ₃, HNO ₂The method of blending ingredients concentration.

Background technology

In nuclear fuel aftertreatment Purex flow process was controlled, it was the main reference data of determining process conditions that uranic acid distributes, and the analysis site of uranium is many, and analysis frequency is high, and the concentration range span is large, and existing aqueous sample also has organic phase sample.The existence meeting of nitrous acid is controlled aftertreatment technology and is exerted an influence, and such as affecting the trend of neptunium in the 1A groove, affects the valence distribution of neptunium, plutonium and fission product, after entering uranium plutonium separating cycle, can destroy reductive agent, can destroy detachment process fully when serious.Therefore set up accurately, the method for Fast Measurement uranic acid and nitrous acid content is very important.

Titrimetry, HNO are adopted in the analysis of constant U at present usually ₂Analysis adopt colourimetry more, aqueous sample need dilute rear measurement, organic phase sample is measured after needing back extraction to enter water again.These analytical approachs all need the long time, and can produce a large amount of radioactive liquid wastes in analytic process.

At Chinese patent, denomination of invention is: multiple-component spectrum analyzing process, number of patent application is: disclose in 96114219.7 patent documentation and a kind of least square method is applied in the spectrophotometric analysis method, found the solution the method for unknown solution concentration.Need to obtain the standard spectrogram of various components to be measured in the step 1 of the method on surveying instrument, the practical operation step that obtains this standard spectrogram is very complicated.In addition, utilize the formula that provides in the document can't the each component densimeter in the organic phase mixed solution be calculated.

Summary of the invention

(1) goal of the invention

Be the technical matters for prior art, a kind of direct mensuration U, HNO are provided ₃, HNO ₂The method of blending ingredients concentration, the method do not need to measure the standard spectrogram of each component to be measured, can also measure simultaneously the concentration of component to be measured in water and organic phase.

(2) technical scheme

A kind of U, HNO of directly measuring ₃, HNO ₂The method of blending ingredients concentration, its step is as follows:

A) water and the organic phase standard model of m variable concentrations of preparation;

B) aqueous sample take deionized water as reference, is measured absorbance; Organic phase sample is measured absorbance take 30%TBP-kerosene as reference;

C) in 400～500nm wavelength coverage, the upper Wave crest and wave trough of the second-order differential spectrum position of choosing absorption of sample spectrum is representational wavelength location, with absorbance, U concentration and the HNO of m water standard model at this wavelength place ₃Concentration substitution formula (1) solves coefficient F ₁, F ₂, F ₃

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2---\left(1\right)$

In 350～400nm wavelength coverage, with absorbance, U concentration, acidity and the HNO of m water standard model characteristic wave strong point ₂Concentration substitution formula (2) solves coefficient F ₁～F ₄Value.

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2+F_4{c}_{m{\mathrm{HNO}}_2}---\left(2\right)$

In 400～500nm wavelength coverage, absorbance and U concentration substitution formula (3) with m organic phase standard model characteristic wave strong point solve coefficient F ₁Value.

A _m=F ₁C _mU （3）

In 350～400nm wavelength coverage, with absorbance, U concentration and the HNO of m organic phase standard model characteristic wave strong point ₂Concentration substitution formula (4) solves coefficient F ₁, F ₂Value.

$A_m=F_1{C}_{\mathrm{mU}}+F_2{C}_{m{\mathrm{HNO}}_2}---\left(4\right)$

D) for the water unknown sample, measure each solution in the absorption spectra of 350～500nm.The required coefficient F of substitution, solve U concentration and HNO with formula (1) in 400～500nm scope ₃Concentration, the required coefficient F of substitution in 350～400nm scope solves an equation with formula (2) and tries to achieve HNO ₂Concentration;

For the organic phase unknown sample, measure each solution in the absorption spectra of 350～500nm.Substitution coefficient F in 400～500nm scope solves U concentration with formula (3), and the required coefficient F of substitution in 350～400nm scope is solved an equation by formula (4) and tries to achieve HNO ₂Concentration.

(3) technique effect

The invention provides a kind of direct mensuration U, HNO ₃, HNO ₂The method of blending ingredients concentration, the method do not need to measure the standard spectrogram of each component to be measured, can also measure simultaneously the concentration of component to be measured in water and organic phase.The method is easy, quick, need not the Chemical Decomposition operation, the spectrophotometric Spectra Unfolding Methods that can directly analyze multicomponent system.

The SIMULTANEOUS DETERMINATION multicomponent system has need not introduce reagent, do not need Chemical Decomposition and the characteristics such as easy and simple to handle.The meaning of direct spectrophotometry is: 1) can save Chemical Decomposition, this is that the scientific worker is desired; 2) analysis result is true, and the state of research object can not change because of chemical separation process; 3) for radioactive sample etc., only need a simple scanning to get final product, reduced analyst's hot operation; 4) can not produce radioactive liquid waste because of the reason of analyzing, and adopt other chemical analysis such as titrimetry, colourimetry etc. all can bring a large amount of radioactive liquid wastes.

Description of drawings

Fig. 1 U (VI), HNO ₂And HNO ₃Absorption spectra;

1——1.0mol/L HNO ₃;

2——0.002mol/L HNO ₂+1.0mol/L HNO ₃;

3——23.8g/L U(VI)+1.0mol/L HNO ₃。

11.9g/L U (VI)-HNO in Fig. 2 aqueous solution and 30%TBP-kerosene ₃-HNO ₂At different HNO ₃Absorption spectra during concentration;

(a):4——1.0mol/L HNO ₃,

5——3.0mol/L HNO ₃,

6——5.0mol/L HNO ₃

(b):7——0.30mol/L HNO ₃,5.1×10 ^-4mol/L HNO ₂;

8——0.10mol/L HNO ₃,1×10 ^-3mol/L HNO ₂;

9——0.50mol/L HNO ₃,2×10 ^-3mol/L HNO ₂

Fig. 3 23.8g/L U (VI)-1.0mol/L HNO ₃-1 * 10 ^-3Mol/L HNO ₂Absorption spectra (a) and second-order differential spectrum (b).

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in detail.

Embodiment 1:

The invention provides a kind of direct mensuration U, HNO ₃, HNO ₂The method of blending ingredients concentration is for U and HNO in the uranium line ₂Fast, Direct Analysis, with Application of Statistic Methods in HNO ₃U, HNO in aqueous solution and 30%TBP-kerosene ₃And HNO ₂Direct solution analysis of spectrum, use least square method measurement data calculated, analyzed, method has statistical property.Its step is as follows:

A) water and the organic phase standard model of m variable concentrations of preparation;

B) aqueous sample take deionized water as reference, in 350～500nm wavelength coverage, is measured absorbance every 0.5nm with the 1cm cuvette; Organic phase sample is measured absorbance take 30%TBP-kerosene as reference with method;

C) in 400～500nm wavelength coverage, the upper Wave crest and wave trough of the second-order differential spectrum position of choosing absorption of sample spectrum is representational wavelength location, with absorbance, U concentration and the HNO of m water standard model at this wavelength place ₃Concentration substitution formula (1) solves coefficient F ₁, F ₂, F ₃(table 1).

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2---\left(1\right)$

In 350～400nm wavelength coverage, with absorbance, U concentration, acidity and the HNO of m water standard model characteristic wave strong point ₂Concentration substitution formula (2) solves coefficient F ₁～F ₄Value (table 2).

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2+F_4{c}_{m{\mathrm{HNO}}_2}---\left(2\right)$

In 400～500nm wavelength coverage, absorbance and U concentration substitution formula (3) with m organic phase standard model characteristic wave strong point solve coefficient F ₁Value (table 3).

A _m=F ₁C _mU （3）

In 350～400nm wavelength coverage, with absorbance, U concentration and the HNO of m organic phase standard model characteristic wave strong point ₂Concentration substitution formula (4) solves coefficient F ₁, F ₂Value (table 4).

$A_m=F_1{C}_{\mathrm{mU}}+F_2{C}_{m{\mathrm{HNO}}_2}---\left(4\right)$

D) for the water unknown sample, measure each solution in the absorption spectra of 350～500nm.The required coefficient F of substitution, solve U concentration and HNO with formula (1) in 400～500nm scope ₃Concentration, the required coefficient F of substitution in 350～400nm scope solves an equation with formula (2) and tries to achieve HNO ₂Concentration;

For the organic phase unknown sample, measure each solution in the absorption spectra of 350～500nm.Substitution coefficient F in 400～500nm scope solves U concentration with formula (3), and the required coefficient F of substitution in 350～400nm scope is solved an equation by formula (4) and tries to achieve HNO ₂Concentration.

Fig. 1 is uranium, nitric acid and nitrous acid absorption spectra separately, can find out that uranium all has absorption in the whole wavelength coverage of 350～500nm, and nitrous acid has absorption at 350～400nm, nitric acid all without absorbing, but can exert an influence in the absorption spectra of aqueous phase nitric acid to uranium and nitrous acid in whole wavelength coverage, as shown in figure (Fig. 2 (a)), under certain uranium concentration, in 400～500nm scope, along with the increase of acidity, absorbance increases thereupon.And along with the variation of acidity, uranium also changes in the relative height of two acromions of 405nm and 428nm place, reflects that the form complexed of uranyl-nitric acid complex compound changes because acidity is different.And in organic phase (Fig. 2 (b)), uranium is extracted with the form of neutral complex, the basic acid and alkali degree impact of the light absorption value of uranium.

In 400～500nm scope, only have the complex compounds at different levels of uranyl-nitrate radical that absorption band is arranged, at 1～5mol/L HNO ₃The time, HNO ₃In aqueous solution, U is mainly with UO ₂ ²⁺, UO ₂NO ₃ ⁺, UO ₂(NO ₃) ₂Form exist.Its absorbance can be expressed as:

$A=E_1{c}_{{\mathrm{UO}}_2^{2+}}+E_2{c}_{{\mathrm{UO}}_2{{\mathrm{NO}}_3}^{+}}+E_3{c}_{{\mathrm{UO}}_2{\left({\mathrm{NO}}_3\right)}_2}$

Cause:

Its equilibrium constant is respectively K ₁, K ₂, the substitution following formula gets:

$A=E_1{c}_{{\mathrm{UO}}_2^{2+}}+E_2{K}_1{c}_{{\mathrm{UO}}_2^{2+}}{c}_{{\mathrm{NO}}_3^{-}}+E_3{K}_2{c}_{{\mathrm{UO}}_2^{2+}}{c}_{{\mathrm{NO}}_3^{-}}^2$

Merging constant term gets:

$A=F_1{c}_{{\mathrm{UO}}_2^{2+}}+F_2{c}_{{\mathrm{UO}}_2^{2+}}{c}_{{\mathrm{NO}}_3^{-}}+F_3{c}_{{\mathrm{UO}}_2^{2+}}{c}_{{\mathrm{NO}}_3^{-}}^2$

In 350～400nm scope, due to the existence of nitrous acid, absorbance is expressed as:

$A=F_1{c}_{{\mathrm{UO}}_2^{2+}}+F_2{c}_{{\mathrm{UO}}_2{{\mathrm{NO}}_3}^{+}}+F_3{c}_{{\mathrm{UO}}_2{\left({\mathrm{NO}}_3\right)}_2}+F_4{c}_{{\mathrm{HNO}}_2}$

In 30%TBP kerosene, U mainly is extracted with the form of neutral complex, and in 400～500nm scope, absorbance is expressed as:

In 350～400nm scope, absorbance is expressed as: $A=F_1{c}_{{\mathrm{UO}}_2^{2+}}+F_2{c}_{{\mathrm{HNO}}_2}.$

If detected solution contains k kind component, their concentration separately is c _i(i=1,2 ..., k), each component is E at the molar extinction coefficient at a certain wavelength place _i(i=1,2 ..., k), when analytic sample is scanned, according to Bill's absorption law, at λ _j(j=1,2 ..., n) locate absorbance approximate satisfied (using the 1cm cuvette):

$A_j=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}{c}_i{E}_{\mathrm{ij}}$

$=c_1{E}_{1j}+c_2{E}_{2j}+\·\·\·\·\·\·+c_k{E}_{\mathrm{kj}}---\left(5\right)$

To a certain component, in wavelength X _jThe place, E _ijBe constant, if E _ijKnown, can try to achieve c by (5) formula _i

Preparation m(m=1,2 ..., M, the individual standard model of M＞k) records sample at λ ₁～λ _nAbsorption spectrum in scope can provide λ thus ₁～λ _nCertain wavelength X in scope _jThe absorbance expression formula of m the standard model in place:

$\left\{\begin{array}{c}{A}_1=E_1{c}_{11}+E_2{c}_{12}+\·\·\·\·\·\·+E_k{c}_{1k}\\ A_2=E_1{c}_{21}+E_2{c}_{22}+\·\·\·\·\·\·E_k{c}_{2k}\\ \·\·\·\·\·\·\\ A_M=E_1{c}_{M1}+E_2{c}_{M2}+\·\·\·\·\·\·+E_k{c}_{\mathrm{Mk}}\end{array}\right.---\left(6\right)$

Each concentration of component c _M,kFor known, according to principle of least square method solving equations (6), obtain certain wavelength X _jLocate the E of each component _iValue in like manner can obtain other analyzing spot λ _j(j=1,2 ..., the Ei value of n) locating.Coefficient E in formula is the value of trying to achieve through mathematical statistics, and the Wave crest and wave trough of composing due to second-order differential is representational wavelength location (Fig. 3), in experiment, selects the interior representational characteristic wavelength of sweep limit to do statistical computation.

To a certain unknown sample, each analyzing spot of substitution λ _jThe E at place _iValue, formula (5) can be converted into system of equations:

$\left\{\begin{array}{c}{A}_1=E_{11}{c}_1+E_{21}{c}_2+\·\·\·\·\·\·+E_{k1}{c}_k\\ A_2=E_{12}{c}_1+E_{22}{c}_2+\·\·\·\·\·\·E_{k2}{c}_k\\ \·\·\·\·\·\·\\ A_n=E_{1n}{c}_1+E_{2n}{c}_2+\·\·\·\·\·\·+E_{\mathrm{kn}}{c}_k\end{array}\right.---\left(7\right)$

According to principle of least square method solving equations (7), all components concentration c _iJust can try to achieve one by one.

Use this solution spectrometry, at HNO ₃In aqueous solution or 30%TBP-kerosene, U and HNO ₃Concentration can try to achieve by spectrum unscrambling in 400～500nm scope, HNO ₂Concentration can be found the solution in 350～400nm scope.At water ρ (U)=0.95～74.1g/L, c (HNO ₃)=3～5mol/L, c (HNO ₂)=5 * 10 ^-4～2 * 10 ^-3During mol/L, U, HNO ₃And HNO ₂The relative standard deviation of measuring is respectively 0.46%, 0.68% and 4.09%; In organic phase, ρ (U)=1～74.1g/L, c (HNO ₂)=5 * 10 ^-4～2 * 10 ^-3During mol/L, U and HNO ₂The relative standard deviation of measuring is respectively 0.42% and 4.2%.Result accurately and reliably.

Utilize spectrophotometric solution spectrometry Direct Analysis U, HNO ₃, HNO ₂Can easyly provide rapidly analysis result, be suitable for general industrial analysis and the control of not accounting as material in the U line, need not Chemical Decomposition and analytic process can not produce radioactive liquid waste.

Table 1 HNO ₃The F value at different wave length place in 400～500nm scope in aqueous solution

Table 2 HNO ₃The F value at different wave length place in 350～400nm scope in aqueous solution

The F value at different wave length place in 400～500nm scope in table 3 30%TBP-kerosene

The F value at different wave length place in 350～400nm scope in table 4 30%TBP-kerosene

U, HNO in aqueous solution ₃, HNO ₂Analyze

The standard U solution of preparation variable concentrations is measured each solution in the absorption spectra of 350～500nm.The required coefficient F of substitution, solve an equation and try to achieve HNO in 350～400nm scope ₂Concentration; Substitution coefficient F, solve U concentration and HNO in 400～500nm scope ₃Concentration.The results are shown in table 5.

Table 5 HNO ₃U, HNO in aqueous solution ₃, HNO ₂Analysis result

U, HNO in 30%TBP-kerosene ₂Analyze

The standard U solution of preparation variable concentrations is measured each solution in the absorption spectra of 350～500nm.The required coefficient F of substitution, solve an equation and try to achieve HNO in 350～400nm scope ₂Concentration; Substitution coefficient F, solve U concentration in 400～500nm scope.The results are shown in table 6.

U, HNO in table 6 30%TBP-kerosene ₂Analysis result

Obviously, those skilled in the art can carry out various changes and modification and not break away from the spirit and scope of the present invention the present invention.Like this, if within of the present invention these are revised and modification belongs to the scope of claim of the present invention and equivalent technology thereof, the present invention also is intended to comprise these changes and modification interior.

Claims (2)

1. directly measure U, HNO for one kind ₃, HNO ₂The method of blending ingredients concentration, its step is as follows:

A) water and the organic phase standard model of m variable concentrations of preparation;

B) aqueous sample take deionized water as reference, is measured absorbance; Organic phase sample is measured absorbance take 30%TBP-kerosene as reference;

C) in 400～500nm wavelength coverage, the upper Wave crest and wave trough of the second-order differential spectrum position of choosing absorption of sample spectrum is representational wavelength location, with absorbance, U concentration and the HNO of m water standard model at this wavelength place ₃Concentration substitution formula (1) solves coefficient F ₁, F ₂, F ₃

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2---\left(1\right)$

In 350～400nm wavelength coverage, with absorbance, U concentration, acidity and the HNO of m water standard model characteristic wave strong point ₂Concentration substitution formula (2) solves coefficient F ₁～F ₄Value.

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2+F_4{c}_{m{\mathrm{HNO}}_2}---\left(2\right)$

In 400～500nm wavelength coverage, absorbance and U concentration substitution formula (3) with m organic phase standard model characteristic wave strong point solve coefficient F ₁Value.

A _m=F ₁C _mU （3）

In 350～400nm wavelength coverage, with absorbance, U concentration and the HNO of m organic phase standard model characteristic wave strong point ₂Concentration substitution formula (4) solves coefficient F ₁, F ₂Value.

$A_m=F_1{C}_{\mathrm{mU}}+F_2{C}_{m{\mathrm{HNO}}_2}---\left(4\right)$

D) for the water unknown sample, measure each solution in the absorption spectra of 350～500nm.The required coefficient F of substitution, solve U concentration and HNO with formula (1) in 400～500nm scope ₃Concentration, the required coefficient F of substitution in 350～400nm scope solves an equation with formula (2) and tries to achieve HNO ₂Concentration;

For the organic phase unknown sample, measure each solution in the absorption spectra of 350～500nm; Substitution coefficient F in 400～500nm scope solves U concentration with formula (3), and the required coefficient F of substitution in 350～400nm scope is solved an equation by formula (4) and tries to achieve HNO ₂Concentration.

2. U, the HNO of directly measuring according to claim 1 ₃, HNO ₂The method of blending ingredients concentration is characterized in that: step wherein

C) in 450～500nm wavelength coverage, the upper Wave crest and wave trough of the second-order differential spectrum position of choosing absorption of sample spectrum is representational wavelength location, with absorbance, U concentration and the HNO of m water standard model at this wavelength place ₃Concentration substitution formula (1) solves coefficient F ₁, F ₂, F ₃

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2---\left(1\right)$

In 375～400nm wavelength coverage, with absorbance, U concentration, acidity and the HNO of m water standard model characteristic wave strong point ₂Concentration substitution formula (2) solves coefficient F ₁～F ₄Value.

$A_m=F_1{c}_{m{\mathrm{UO}}_2^{2+}}+F_2{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}+F_3{c}_{m{\mathrm{UO}}_2^{2+}}{c}_{m{\mathrm{NO}}_3^{-}}^2+F_4{c}_{m{\mathrm{HNO}}_2}---\left(2\right)$

In 450～500nm wavelength coverage, absorbance and U concentration substitution formula (3) with m organic phase standard model characteristic wave strong point solve coefficient F ₁Value.

A _m=F ₁C _mU （3）

In 375～400nm wavelength coverage, with absorbance, U concentration and the HNO of m organic phase standard model characteristic wave strong point ₂Concentration substitution formula (4) solves coefficient F ₁, F ₂Value.

$A_m=F_1{C}_{\mathrm{mU}}+F_2{C}_{m{\mathrm{HNO}}_2}---\left(4\right)$

D) for the water unknown sample, measure each solution in the absorption spectra of 375～500nm.The required coefficient F of substitution, solve U concentration and HNO with formula (1) in 450～500nm scope ₃Concentration, the required coefficient F of substitution in 375～400nm scope solves an equation with formula (2) and tries to achieve HNO ₂Concentration;

For the organic phase unknown sample, measure each solution in the absorption spectra of 375～500nm; Substitution coefficient F in 450～500nm scope solves U concentration with formula (3), and the required coefficient F of substitution in 375～400nm scope is solved an equation by formula (4) and tries to achieve HNO ₂Concentration.

Images