CN104198484A - Method for testing fluorine content in solution - Google Patents

Abstract

The invention relates to a method for testing fluorine content in a solution. The adopted the technical scheme comprises the following steps: adding deionized water into a conical flask, then accurately transferring a fluorine ion solution to be tested into the conical flask, shaking fully uniformly, adding potassium nitrate, accurately transferring a standard lanthanum nitrate solution into the conical flask, uniformly mixing, regulating the pH of the solution to be 1.0-3.0, heating and boiling for 1-2 minutes, and cooling to the room temperature; adding 10mL of acetate-sodium acetate buffered solution and five to six drops of xylenol orange indicator, and dripping into an EDTA (Ethylene Diamine Tetraacetic Acid) standard solution until the solution turns bright yellow from prunosus. The method is simple and environment-friendly and can test the fluorine ion content in the fluoride solution of which the fluorine ion concentration is greater than 0.1mg/mL.

Description

A kind of method of measuring fluorine content in solution

Technical field

The present invention relates to the assay method of fluorine content in a kind of solution, particularly a kind of assay method that is greater than 0.1mg/mL for fluorinion concentration in solution.

Background technology

At present in solution, the measuring method of fluorine content mainly contains distillation-thorium nitrate volumetric method and fluoride ion selective electrode method, and in distillation-thorium nitrate volumetric method, thorium nitrate has radioactivity, purchase controlled, very large to operator and environmental hazard.Fluoride ion selective electrode method has limitation, and it is more accurate for the measurement of fluorine content in the lower aqueous solution of concentration, and inaccurate for the higher fluorine content measurement of concentration.

Summary of the invention

The object of this invention is to provide that a kind of method is simple, environmental protection, be greater than fluorine content determination method in the fluorine-containing solution of 0.1mg/mL for fluorinion concentration.

The technical solution used in the present invention is: a kind of method of measuring fluorine content in solution, method is as follows: the deionized water that adds about 100mL in Erlenmeyer flask, then accurately pipette 0.5-1.0mL fluoride ion liquid to be measured and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately pipette 30.00-80.00mL lanthanum nitrate standard solution in Erlenmeyer flask, mix, regulator solution pH=1.0-3.0,1-2min is boiled in heating, is cooled to room temperature; Add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, drops to solution become glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows F ^-the content of ion:

$C=\frac{F\×(V_{\mathrm{La}}-K\×V_E)}{V_F}\×1000$

In formula: the concentration of C-F ion, g/L;

The quality of the fluorine of F-suitable with 1mL lanthanum nitrate standard solution, g;

V _la-add the volume of lanthanum nitrate standard solution, mL;

V _e-titration consumes the volume of EDTA standard solution, mL;

V _f-pipette the volume of fluoride ion liquid to be measured, mL;

K-1mL EDTA standard solution is converted into the coefficient of lanthanum nitrate standard solution volume.

The method of fluorine content in above-mentioned mensuration solution, in formula, definite method of F value is as follows: the deionized water that adds about 100mL in Erlenmeyer flask, then accurately pipette 5.00-10.00mL fluorine standard solution and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately pipette 15.00mL lanthanum nitrate standard solution in Erlenmeyer flask, mix, regulator solution pH=1.0-3.0,1-2min is boiled in heating, is cooled to room temperature; Add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, drops to solution become glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows F value:

$F=\frac{C_0\×V_0}{1000\×(15-K\×V_0^{\′})}$

In formula: the quality of the fluorine that F-1mL lanthanum nitrate standard solution is suitable, g;

C ₀the concentration of-fluorine standard solution, mg/mL;

V ₀the volume of-fluorine standard solution, mL;

K-1mL EDTA standard solution is converted into the coefficient of lanthanum nitrate standard solution volume;

V ' ₀-titration consumes the volume of EDTA standard solution, mL.

The method of fluorine content in above-mentioned mensuration solution, the concentration of described fluorine standard solution is 0.990-1.010mg/mL

The method of fluorine content in above-mentioned mensuration solution, in formula, definite method of K value is as follows: accurately pipette 10.00-20.00mL lanthanum nitrate standard solution in 500mL conical beaker, be diluted with water to 150mL, add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, is titrated to solution becomes glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows K value:

$K=\frac{V_1}{V_2}$

In formula: V ₁-lanthanum nitrate standard solution the volume of getting, mL;

V ₂-titration consumes EDTA standard solution volume, mL.

The method of fluorine content in above-mentioned mensuration solution, the concentration of described lanthanum nitrate standard solution is 11.0000-12.0000g/L.

The method of fluorine content in above-mentioned mensuration solution, the concentration of described EDTA standard solution is 9.90-10.10mg/mL.

Principle of the present invention is: the present invention adds excessive lanthanum nitrate hexahydrate under pH=1.0-3.0, makes La ³⁺with F ^-generate LaF ₃precipitation, then in acetic acid-sodium acetate buffer solution of pH=5.5-6.0, taking xylenol orange as indicator, with the lanthanum nitrate of EDTA titer overtitration.

The invention has the beneficial effects as follows: the inventive method is simple, environmentally safe, measurement result is accurate, has good reappearance.

Embodiment

(1) material:

1) potassium nitrate: analyze pure

2) xylenol orange: 5g/l

3) hydrochloric acid solution: 20% (v/v)

4) sodium hydroxide solution: 20g/l

5) acetic acid-sodium acetate buffer solution (pH=5.5-6.0)

Compound method: take 200g crystallization sodium acetate (CH ₃cOONa3H ₂o) in beaker, add deionized water solution, add 10mL glacial acetic acid, be settled to 1L with deionized water.

6) fluorine standard solution

Compound method: pure top grade sodium fluoride is dried until constant weight at 180 DEG C.Accurately take the sodium fluoride 2.2101g of drying to constant weight in beaker, add deionized water and fully dissolve, move in the volumetric flask of 1L, be settled to 1L, obtaining concentration is the fluorine standard solution of 1.000mg/mL, stores with polyethylene bottle.

7) lanthanum nitrate standard solution

Compound method: accurately take 11.964g La (NO ₃) ₃6H ₂o, in 500mL beaker, adds deionized water dissolving, is then settled to 1L, and obtaining concentration is the lanthanum nitrate standard solution of 8.980g/L.

8) EDTA standard solution

Compound method: accurately take 10.000g disodium ethylene diamine tetraacetate in 500mL conical beaker, add after deionized water dissolving, be settled to 1L with deionized water, obtaining concentration is the EDTA standard solution of 10.00mg/mL.

(2) method

1) method of testing

Get 500mL Erlenmeyer flask, first add the deionized water of about 100mL, then accurately pipette fluoride ion liquid (V to be measured _f) be placed in the Erlenmeyer flask that adds 100mL deionized water, fully shake up, add 2g potassium nitrate, accurately pipette lanthanum nitrate standard solution (V _la), then measure the pH value of solution, be adjusted to pH=1.0-3.0 with sodium hydroxide solution and 20% hydrochloric acid of 20g/L, 1-2min is boiled in heating, takes off, and is cooled to room temperature.Add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, drops to solution become glassy yellow from aubergine and be terminal (volume is designated as V with EDTA standard solution _e).

The parallel titration of each sample three times, the titration volume of EDTA standard solution is averaged, and is calculated as follows F ^-the content of ion, represents with mass concentration (g/L):

$C=\frac{F\×(V_{\mathrm{La}}-K\×V_E)}{V_F}\×1000$

In formula: C-F ^-the concentration of ion, g/L

V _la-add the volume of lanthanum nitrate standard solution, mL

V _e-titration consumes EDTA standard solution volume, mL

V _f-pipette the volume of fluoride ion liquid to be measured, mL

2) in formula K value determine

Method: accurately pipette 20.00mL lanthanum nitrate standard solution in 500mL conical beaker, be diluted with water to 150mL, add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, is titrated to solution becomes glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows K value, obtain K=0.8197:

$K=\frac{V_1}{V_2}$

In formula: K-1mL EDTA standard solution is converted into the coefficient of lanthanum nitrate standard solution volume;

V ₁-lanthanum nitrate standard solution the volume (20.00mL) of getting;

V ₂-titration consumes EDTA standard solution volume (24.4mL).

3) in formula F value determine

Method: the deionized water that adds about 100mL in Erlenmeyer flask, then accurately pipette 10.00mL fluorine standard solution and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately pipette 15.00mL lanthanum nitrate standard solution in Erlenmeyer flask, mix, with hydrochloric acid and sodium hydroxide solution regulator solution pH=1.0-3.0,1-2min is boiled in heating, is cooled to room temperature; Add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, drops to solution become glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows F value, obtain F=0.00178;

$F=\frac{C_0\×V_0}{1000\×(15-K\×V_0^{\′})}$

In formula: the quality of the fluorine that F-1mL lanthanum nitrate standard solution is suitable, g;

C ₀the concentration (1mg/mL) of-fluorine standard solution;

V ₀the volume (10mL) of-fluorine standard solution;

K-1mL EDTA standard solution is converted into the coefficient (0.8197) of lanthanum nitrate standard solution volume;

V ' ₀-titration consumes the volume (11.43mL) of EDTA standard solution.

Embodiment 1:

Get 500mL Erlenmeyer flask, first add the deionized water of about 100mL, then accurately pipette 1.0mL HF solution (concentration known is 45.0g/L) and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately pipette 75.00mL lanthanum nitrate standard solution in Erlenmeyer flask, regulating pH value is 2.5, and 2min is boiled in heating, be cooled to room temperature, add 10mL acetic acid-sodium acetate buffer solution, 5 xylenol orange indicator, drop to solution with EDTA standard solution and become glassy yellow from aubergine.Parallel titration three times, consumes that the amount of EDTA is respectively 61.9,61.8., 62.0mL, calculates F ^-ion concentration is 45.4g/L.

Embodiment 2:

Get 500mL Erlenmeyer flask, first add the deionized water of about 100mL, then accurately pipette the titanium chemical milling solution that 0.5mL is about 47.0g/L containing HF concentration and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately add 40.00mL lanthanum nitrate titer in Erlenmeyer flask, be about 2.0 with sodium hydroxide solution and the 20% salt acid for adjusting pH value of 20g/L, add and boil 2min, take off water-cooled to room temperature, add 10mL acetic acid-sodium acetate buffer solution, 5 xylenol orange indicator, dropping to solution with EDTA standard solution becomes glassy yellow from aubergine and is terminal, consume EDTA and be respectively 33.2, 33.5, 33.3mL, calculate F in titanium chemical milling solution ^-ion concentration is 47.4g/L.

Embodiment 3:

Get 500mL Erlenmeyer flask, first add the deionized water of about 100mL, the titanium chemical milling solution that then accurately pipettes the concentration 21.3g/L of 0.5mL HF is placed in Erlenmeyer flask, fully shakes up, add 2g potassium nitrate, accurately add 75.00mL lanthanum nitrate standard solution in Erlenmeyer flask, regulate pH to approximately 2.0,2min is boiled in heating, take off water-cooled to room temperature, add 10mL acetic acid-sodium acetate buffer solution, 5 xylenol orange indicator, drop to solution with EDTA standard solution and become glassy yellow from aubergine.Parallel titration three times, consumes that the amount of EDTA is respectively 84.8,84.7,84.5mL, calculates F in titanium chemical milling solution ^-ion concentration is 21.0g/L.

Above embodiment does not limit the present invention, in practical operation, while preparing fluorine standard solution, lanthanum nitrate standard solution and EDTA standard solution, the accurate weighing scale basis of calculationJi concentration value weighing according to reality, in K and the F value determined according to actual standard concentration value in computing formula at every turn.

Claims (6)

1. measure the method for fluorine content in solution for one kind, it is characterized in that method is as follows: the deionized water that adds about 100mL in Erlenmeyer flask, then accurately pipette 0.5-1.0mL fluoride ion liquid to be measured and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately pipette 30.00-80.00mL lanthanum nitrate standard solution in Erlenmeyer flask, mix, regulator solution pH=1.0-3.0,1-2min is boiled in heating, is cooled to room temperature; Add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, drops to solution become glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows F ^-the content of ion:

$C=\frac{F\×(V_{\mathrm{La}}-K\×V_E)}{V_F}\×1000$

In formula: C-F ^-the concentration of ion, g/L;

The quality of the fluorine of F-suitable with 1mL lanthanum nitrate standard solution, g;

V _la-add the volume of lanthanum nitrate standard solution, mL;

V _e-titration consumes the volume of EDTA standard solution, mL;

V _f-pipette the volume of fluoride ion liquid to be measured, mL;

K-1mL EDTA standard solution is converted into the coefficient of lanthanum nitrate standard solution volume.

2. the method for fluorine content in mensuration solution as claimed in claim 1, it is characterized in that: in formula, definite method of F value is as follows: the deionized water that adds about 100mL in Erlenmeyer flask, then accurately pipette 5.00-10.00mL fluorine standard solution and be placed in Erlenmeyer flask, fully shake up, add 2g potassium nitrate, accurately pipette 15.00mL lanthanum nitrate standard solution in Erlenmeyer flask, mix, regulator solution pH=1.0-3.0,1-2min is boiled in heating, is cooled to room temperature; Add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, drops to solution become glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows F value:

$F=\frac{C_0\×V_0}{1000\×(15-K\×V_0^{\′})}$

In formula: the quality of the fluorine that F-1mL lanthanum nitrate standard solution is suitable, g;

C ₀the concentration of-fluorine standard solution, mg/mL;

V ₀the volume of-fluorine standard solution, mL;

K-1mL EDTA standard solution is converted into the coefficient of lanthanum nitrate standard solution volume;

V ' ₀-titration consumes the volume of EDTA standard solution, mL.

3. the method for fluorine content in mensuration solution as claimed in claim 2, is characterized in that: the concentration of described fluorine standard solution is 0.990-1.010mg/mL.

4. the method for fluorine content in mensuration solution as claimed in claim 1, it is characterized in that: in formula, definite method of K value is as follows: accurately pipette 10.00-20.00mL lanthanum nitrate standard solution in 500mL conical beaker, be diluted with water to 150mL, add 10mL acetic acid-sodium acetate buffer solution, 5-6 drips xylenol orange indicator, is titrated to solution becomes glassy yellow from aubergine and be terminal with EDTA standard solution; Be calculated as follows K value:

$K=\frac{V_1}{V_2}$

In formula: V ₁-lanthanum nitrate standard solution the volume of getting, mL;

V ₂-titration consumes EDTA standard solution volume, mL.

5. the method for fluorine content in the mensuration solution as described in claim 1,2,3 or 4, is characterized in that: the concentration of described lanthanum nitrate standard solution is 8.500-10.000g/L.

6. the method for fluorine content in the mensuration solution as described in claim 1,2,3 or 4, is characterized in that: the concentration of described EDTA standard solution is 9.90-10.10mg/mL.