CN102226799A - Detection method capable of eliminating interference in Al2O3 analysis process of metallurgy refractory - Google Patents

Abstract

The invention discloses a detection method capable of eliminating interference in Al2O3 analysis process of metallurgy refractory. The method comprises the following steps of: firstly, accurately weighing a sample to be detected, then, adding a mixed fusing agent, adding hot water for leaching a fusion cake after the sample is fused, setting constant volume, and performing dry filtering to get a filtrate A; proportionally taking the filtrate A, and then, adding nitrophenol solution; adjusting color of the solution to change just from yellow to colorless with 1:1 hydrochloric acid, adding cupferron, readjusting the color to change just from yellow to colorless, setting constant volume, and performing dry filtering to get a filtrate B; proportionally taking 100ml of the filtrate B, adding excessive amount of disodium EDTA (ethylene diamine tetra acetic acid) standard solution, further adding acet-sodium acetate buffer solution, boiling, cooling, adding an xylenol orange indicator, and titrating the solution to change from yellow to red, namely the end point, through zinc acetate standard solution. The method provided by the invention perfectly solves the problem of interference caused by a large amount of residual elements, so that the indicator is sensitive in the titration endpoint, changes can be easily observed, and accuracy of analysis result is improved; and the method is simple and convenient in operation, and excellent in reproducibility of the analysis result.

Description

Can eliminate Al in the metallurgical anti-material 2O 3The detection method of disturbing in the analytic process

(1) technical field: the invention belongs to metallurgical material chemical analysis technology field, be specifically related to a kind of energy and eliminate Al in the metallurgical fire resistive material ₂O ₃The detection method of disturbing in the analytic process.

(2) background technology: extensively use various fire resistive materials in steel-making and the forging process, for example the bell that uses at steelworks waters material feeding, ramming mass, various corundum brick and drainage sand etc., forges casting process and often uses at the bottom of funnel brick, cast tube brick, runner brick, centre runner brick and the ingot mould mould brick etc.All contain a certain proportion of aluminium oxide (generally with Al in the above-mentioned anti-material ₂O ₃Expression), in order to increase inoxidizability, improve sintering character or to improve intensity etc.

Al in the present all kinds of fire resistive material ₂O ₃Chemical analysis method often use traditional EDTA titrimetry, this analytical approach principle is by adding excessive EDTA standard solution, Al in weakly acidic solution ³⁺With the EDTA complexing, be indicator with the xylenol orange, with the excessive EDTA of zinc acetate standard solution titration, replace and Al with villiaumite more earlier ³⁺The EDTA of complexing replaces the EDTA that with the zinc acetate standard solution titration at last, thereby calculates Al ₂O ₃Massfraction.This method is easier, grasps easily, and analyze content range and contain extensivelyr, be one of analytical approach of at first selecting for use at work of many chemical analysis persons.

The xylenol orange indicator that this method is used, be a kind of triphenylmethane developer, the ion complexation of elements such as easy same bismuth, lead, cobalt, copper, vanadium, zirconium forms colored complex, the serious observation of disturbing the final titration end-point of this law causes analysis result inaccurate.In addition, as if iron content, nickel, titanium coloured ion etc. in the sample, also generation has a strong impact on to analytic process.For above-mentioned interference, traditional method generally is to adopt the highly basic separation method.But some separation of metal ions is incomplete, and is still influential to analysis result.

A lot of documents proposed some and eliminated the method that element disturbs, but belonged at some element-specific metallic ion more for this law, did not have broad applicability.

(3) summary of the invention: purpose of the present invention mainly is at the existing problem of the detection method of present use, provides a kind of and can eliminate Al in the metallurgical fire resistive material ₂O ₃The detection method of disturbing in the analytic process; Pass through this law, better having solved many residual elements disturbs, particularly (can't be incomplete by precipitate and separate or the precipitation) common metal ion such as high valence ion to vanadium have separation and wait advantage fully, make indicator in titration end-point variable color acumen, observe easily, improved the analysis result accuracy greatly; This method is easy and simple to handle, grasp easily, and analysis result repeatability (standard deviation) is good.

Reach the foregoing invention purpose, at first for detecting solution, will adopt the highly basic separation method earlier, precipitation is removed a large amount of each metal ion species that generates oxyhydroxide easily.A kind ofly having except that the Al ion by adding, with common metal ion complex reaction takes place easily all, and the complexing product is easy to filter the common reagent of elimination for precipitation, just can reach the effect of thorough elimination common interference metallic ion.

Through screening, it is that this method is used reagent that the inventive method is selected cupferron for use, and its principal feature has:

1, cupferron aqueous solution colorless and odorless, and often sell the market;

2, cupferron can satisfy the solution of all technological difficulties of this assay method substantially;

3, cupferron is PH=2～5 with the best complexing acidity of most of metal cations, and Al ³⁺It is PH=5.5 that the beginning hydrolysis produces precipitation acidity.Cupferron solution is after adding about PH=3, and pH value can be increased to 5～6, causes Al ³⁺Hydrolysis produces precipitation.But this law can not add buffer solution, otherwise influences the subsequent operation step.Observe through test of many times, this law proposes only to note using the finite concentration hydrochloric acid solution to reduce pH value simultaneously, can judge final acidity by the variation of solution turbidity, does not therefore need to add buffer solution, also can be without acidometer.

Detection method concrete steps of the present invention are as follows:

1, the sample that accurately takes by weighing 0.5000g places in the iron crucible, adds the 2.5g mixed flux again, stirs; Described mixed flux is to be mixed by the sodium peroxide of 3 weight portions+1 weight parts of sodium carbonate, iron crucible is melted to sample be transparence on alcohol blast burner, takes off cold slightly, add hot water leaching frit, after the cooling, be settled to 250ml, do and filter, get filtrate A;

2, divide and to get filtrate A 100ml, add mass percentage concentration and be 0.2% paranitrophenol solution 1-2 and drip; Use 1: 1 hydrochloric acid to regulate color then and become colorless by yellow just, adding 10ml mass percentage concentration is 10% cupferron aqueous solution, and readjusting color is colourless by xanthochromia just, and this moment, solution was become limpid by emulsion; Constant volume 200ml does and filters, and gets liquor B;

3, branch is got liquor B 100ml, look sample EDTA two sodium standard solutions that to contain the excessive adding volumetric molar concentration of Al amount height be 0.02mol/L, acetate-the sodium acetate buffer solution that adds 20mlpH5-6 again, heated and boiled 3 minutes, be cooled to room temperature, add acetate-sodium acetate buffer solution of 10ml pH5-6, adding 2-3, to drip mass percentage concentration be 0.5% xylenol orange indicator, is that the zinc acetate standard solution titration of 0.02mol/L becomes redness to solution colour by yellow and is terminal point with volumetric molar concentration;

4, according to the EDTA two sodium standard solution volumes of actual consumption, can calculate aluminium element content in the sample; Its computing formula is as follows:

$w_{\mathrm{Al}2O3}/\%\frac{T\×(V-V1)}{m\×\frac{50}{250}\×1000}\×100$

In the formula:

T: every liter of EDTA two sodium standard solutions are equivalent to the quality of alundum (Al, 1.0196g/L;

V: the volume of EDTA two sodium standard solutions of adding, ml;

V1: the volume of the zinc acetate standard solution that is consumed, ml;

M: take by weighing the quality of sample, g;

50/250: the actual branch of test solution is got ratio.

The present invention has following characteristics:

1, easy and simple to handle, grasp easily, and analysis result repeatability (standard deviation) is good;

2, better having solved many residual elements disturbs, particularly (can't be incomplete by precipitate and separate or the precipitation) common metal ion such as high valence ion to vanadium have separation and wait advantage fully, make indicator in titration end-point variable color acumen, observe easily, improve the analysis result accuracy.

(4) embodiment:

Embodiment 1

1, ramming mass, lower nozzle brick, middle bag coating, drainage sand four duplicate samples that accurately take by weighing 0.5000g respectively place in four iron crucibles, and each adds the 2.5g mixed flux, stirs.Described mixed flux is to be formed by the sodium peroxide of 3 weight portions+1 weight parts of sodium carbonate mixed preparing, melts to transparence then on alcohol blast burner.Take off coldly slightly, add hot water leaching frit, after the cooling, constant volume 250ml does and filters, respectively filtrate A ₁, A ₂, A ₃, A ₄

2, branch is got A ₁, A ₂, A ₃, A ₄Each 100ml of filtrate, adding mass percentage concentration respectively and be 0.2% paranitrophenol aqueous solution 1-2 drips, use 1: 1 hydrochloric acid (promptly 1 part of hydrochloric acid adds 1 part of water) regulator solution to become colorless by yellow just more respectively, adding 10ml mass percentage concentration is 10% cupferron aqueous solution, readjust color and become colorless by yellow just, this moment, solution was become limpid by emulsion; Constant volume 200ml does and filters, and gets liquor B ₁, B ₂, B ₃, B ₄

3, branch is got B ₁, B ₂, B ₃, B ₄Each 100ml of filtrate, look sample EDTA two sodium standard solutions that to contain the excessive respectively adding volumetric molar concentration of Al amount height be 0.02mol/L, acetate-the sodium acetate buffer solution that adds 20mlpH5-6 again, heated and boiled 3 minutes, be cooled to room temperature, add acetate-sodium acetate buffer solution of 10ml pH 5-6, adding 2-3 respectively, to drip mass percentage concentration be 0.5% xylenol orange indicator, is that 0.02mol/L zinc acetate standard solution titration becomes redness to solution by yellow and is terminal point with volumetric molar concentration;

4, according to the EDTA two sodium standard solution volumes of actual consumption, press $w_{\mathrm{Al}2O3}/\%\frac{T\×(V-V1)}{m\×\frac{50}{250}\×1000}\×100$ Calculate respectively and obtain aluminium element content in four duplicate samples.

By 7 times the same sample of four strains is detected, obtains in every kind of sample aluminium element assay mean value as a result, obtain the analysis result standard deviation simultaneously:

The comparative example 1

Be checking cupferron separating effect, we also use existing method that ramming mass, lower nozzle brick, middle bag coating, drainage sand four duplicate samples among the embodiment 1 are compared detection.Operation steps is as follows:

1, ramming mass, lower nozzle brick, middle bag coating, drainage sand four duplicate samples that accurately take by weighing 0.5000g respectively place in four iron crucibles, each adds the 2.5g mixed flux, described mixed flux is to be formed by the sodium peroxide of 3 weight portions+1 weight parts of sodium carbonate mixed preparing, melts to transparence then on alcohol blast burner.Take off coldly slightly, add hot water leaching frit, after the cooling, constant volume 250ml does and filters, respectively filtrate A ₁, A ₂, A ₃, A ₄

2, branch is got A ₁, A ₂, A ₃, A ₄Each 50ml of filtrate, adding mass percentage concentration respectively and be 0.2% paranitrophenol aqueous solution 1-2 drips, use 1: 1 hydrochloric acid (promptly 1 part of hydrochloric acid adds 1 part of water) regulator solution to become colorless by yellow just more respectively, add 2ml sulfosalicylic acid solution (5% aqueous solution), if be aubergine, then need to be heated to 60-70 ℃, take off, use EDTA disodium standard solution titration to the aubergine of 0.02mol/L to disappear while hot, do not remember reading.This step is not separate Fe completely for eliminating ³⁺The interference of ion;

3, look sample EDTA two sodium standard solutions that to contain the excessive respectively adding volumetric molar concentration of Al amount height be 0.02mol/L, acetate-the sodium acetate buffer solution that adds 20ml pH5-6 again, heated and boiled 3 minutes, be cooled to room temperature, add acetate-sodium acetate buffer solution of 10ml pH 5-6, adding 2-3 respectively, to drip mass percentage concentration be 0.5% xylenol orange indicator, is that 0.02mol/L zinc acetate standard solution titration becomes redness to solution by yellow and is terminal point with volumetric molar concentration;

4, according to the EDTA two sodium standard solution volumes of actual consumption, press $w_{\mathrm{Al}2O3}/\%\frac{T\×(V-V1)}{m\×\frac{50}{250}\×1000}\×100$ Calculate respectively and obtain aluminium element content in three duplicate samples.Bag coating test solution is when adding the xylenol orange indicator wherein, and color is redness, can't indicate titration end-point, so use conventional method can't obtain analysis result.In addition, the ramming mass test solution is when adding the xylenol orange indicator, and it is orange that the indicator color also is, and makes that titration end-point is difficult to determine.During other two kinds of material titration in the end, the xylenol orange indicator is by the red process passivation of xanthochromia, and terminal point is difficult for accurately observing.The result is as follows in concrete analysis:

The effect of two kinds of methods is compared as follows shown in the table:

From last table analysis result as can be seen, use conventional method to analyze,, influence endpoint observation, make analysis precision descend, perhaps can not use this law to measure because various interference are difficult for eliminating.And after adding the cupferron separation,, making the analysis result standard deviation obviously dwindle because the titration end-point acumen is easy to observe, analysis precision significantly improves.

Claims (1)

1. can eliminate Al in the metallurgical anti-material ₂O ₃The detection method of disturbing in the analytic process is characterized in that comprising the steps:

A, the sample that accurately takes by weighing 0.5000g place in the iron crucible, add the 2.5g mixed flux again, stir; Described mixed solvent is to be mixed by the sodium peroxide of 3 weight portions+1 weight parts of sodium carbonate, iron crucible is melted to sample be transparence on alcohol blast burner, takes off cold slightly, add hot water leaching frit, after the cooling, be settled to 250ml, do and filter, get filtrate A;

B, divide and to get filtrate A 100ml, add mass percentage concentration and be 0.2% paranitrophenol solution 1-2 and drip; Using 1: 1 hydrochloric acid to regulate color then is colourless by xanthochromia just, and adding 10ml mass percentage concentration is 10% cupferron aqueous solution, and readjusting color is colourless by xanthochromia just, and this moment, solution was become limpid by emulsion; Constant volume 200ml does and filters, and gets liquor B;

C, branch are got liquor B 100ml, look sample EDTA two sodium standard solutions that to contain the excessive adding volumetric molar concentration of Al amount height be 0.02mol/L, acetate-the sodium acetate buffer solution that adds 20mlpH5-6 again, heated and boiled 3 minutes, be cooled to room temperature, add acetate-sodium acetate buffer solution of 10ml pH5-6, adding 2-3, to drip mass percentage concentration be 0.5% xylenol orange indicator, is that the zinc acetate standard solution titration of 0.02mol/L becomes redness to solution colour by yellow and is terminal point with volumetric molar concentration;

D, according to the EDTA two sodium standard solution volumes of actual consumption, can calculate aluminium element content in the sample;

The formula of aluminium element content is as follows in the calculation sample:

$w_{\mathrm{Al}2O3}/\%\frac{T\×(V-V1)}{m\×\frac{50}{250}\×1000}\×100$

In the formula:

T: every liter of EDTA two sodium standard solutions are equivalent to the quality of alundum (Al, 1.0196g/L;

V: the volume of EDTA two sodium standard solutions of adding, ml;

V1: the volume of the zinc acetate standard solution that is consumed, ml;

M: take by weighing the quality of sample, g;

50/250: the actual branch of test solution is got ratio.