CN103185702B - The detection method of paraffin content in a kind of wimet powder - Google Patents
The detection method of paraffin content in a kind of wimet powder Download PDFInfo
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- CN103185702B CN103185702B CN201110446833.7A CN201110446833A CN103185702B CN 103185702 B CN103185702 B CN 103185702B CN 201110446833 A CN201110446833 A CN 201110446833A CN 103185702 B CN103185702 B CN 103185702B
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Abstract
The invention provides the detection method of paraffin content in a kind of wimet powder, adopt the paraffin in organic solvent extraction separation wimet powder, and measure absorbance on infrared luminosity oil content analyzer, calculate paraffin content with reference to working curve.This detection method short, convenient and safe and reliable results consuming time, can be used in detecting multiple sample simultaneously, with low cost, and recovery of standard addition is 98% ~ 103%.
Description
Technical field
The present invention relates to the method for paraffin content in a kind of quick detection wimet powder, particularly relate to the detection method of paraffin content in a kind of wimet powder.
Background technology
In the preparation process of wimet; usual meeting with paraffin as low temperature moulding agent; bonding wimet starting powder such as the starting material such as cobalt powder and tungsten carbide (being called hard alloy material) at low temperature moulding; then through steps such as dewaxing and high temperature sinterings; prepare last carbide-tipped tool etc., wherein shaping is the important step prepared in hard alloy process.Particularly, paraffin mixes with through wet ball grinding and dried hard alloy material with the form of paraffin organism (gasoline, hexane etc.), and the powder then having wrapped up paraffin is bonded together compressing, for follow-up high temperature dewaxing and sintering.
Paraffin forms primarily of normal alkane, and institute comprises methyl and methylene at near-infrared region 2930cm
-1existing characteristics absorbs.In wimet powder, the detection method of paraffin content has thermogravimetry and extraction.Thermogravimetry is: under hydrogen shield atmosphere, and utilize the character of paraffin boiling point lower (300 ~ 500 DEG C), continuous heating is vaporized separation in 2.5 ~ 3.5 hours, then calculates the content of paraffin according to mass loss.After extraction, gas phase-mass spectrometer coupling method is: extracted in organic solvent by the paraffin separated from wimet powder, then detects the content of paraffin by the method for gas phase-mass spectrometer coupling.But these known at present two kinds of methods all exist certain defect, the former detection time is long, and dangerous in hydrogen atmosphere, and the latter's gas phase-mass spectrometer coupling equipment price is expensive and reaction requires higher.
Summary of the invention
For solving the problem, the present invention aims to provide the detection method of paraffin content in a kind of wimet powder, and short, convenient and safe and reliable results consuming time, can be used in detecting multiple sample simultaneously, with low cost.
The present invention utilizes methyl in paraffin and methylene at near-infrared region 2930cm
-1the characteristic that existing characteristics absorbs, provides the detection method of paraffin content in a kind of wimet powder, comprises the following steps:
(1) working curve is set up: take paraffin standard model, add low-grade fever in organic solvent extremely to dissolve completely, be mixed with paraffin standard solution, prepare the paraffin standard solution serial dilutions solution of different paraffin concentration subsequently respectively, moving in cuvette, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measure the absorbance of each paraffin standard solution serial dilutions solution respectively, with paraffin concentration for horizontal ordinate, absorbance is ordinate drawing curve;
(2) paraffin content in wimet powder is detected: take wimet powder testing sample, add lytic agent low-grade fever to be separated to hard alloy material with paraffin, add organic solvent subsequently, fully shake up, proceed in separating funnel and vibrate, after stratification, taking off layer extract moves in volumetric flask, adding described organic solvent constant volume, pipette mixed solution and enter in cuvette from volumetric flask, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measures absorbance, calculates paraffin content in wimet powder with reference to working curve.
Paraffin is water insoluble, and in alcohol and ketone, solubleness is lower, is soluble in phenixin, methenyl choloride, ether, benzene, carbon disulphide, various mineral oil and most plants oil.Preferably, organic solvent of the present invention is selected from one or more in phenixin, methenyl choloride, ether, benzene and carbon disulphide.More preferably, organic solvent is the special phenixin of infrared luminosity oil content analyzer, and this phenixin is 2930cm in wave number
-1place's light absorption value is 0.001 ~ 0.03.Paraffin has higher solubleness in phenixin, under normal temperature, its solubleness is 40g, 50 DEG C time, its solubleness is 60g, therefore low-grade fever is carried out after adding phenixin in the present invention, the solubleness of paraffin can be far longer than the addition of paraffin in wimet powder, thus is dissolved completely by paraffin.
In step (1), paraffin standard model should be identical with the paraffin model in testing sample.For obtaining working curve more accurately, preferably, the quality taking paraffin standard model is accurate to 0.0001g.
" be mixed with paraffin standard solution " and refer to and will be dissolved in the paraffin standard model after organic solvent, move in volumetric flask, with organic solvent diluting to scale, constant volume mixes, and is mixed with paraffin standard solution.Preferably, in paraffin standard solution, the concentration of paraffin is 1000mg/L.
" prepare the paraffin standard solution serial dilutions solution of different paraffin concentration " and refer to the paraffin standard solution pipetting certain volume respectively, be placed in multiple volumetric flask respectively, with organic solvent diluting to scale, constant volume mixes, and is mixed with the paraffin dilute solution of graded series concentration.Preferably, graded series is 4.More preferably, the concentration of paraffin standard solution serial dilutions solution is respectively 10mg/L, 20mg/L, 30mg/L and 40mg/L.
Utilize infrared luminosity oil content analyzer to measure the absorbance of each paraffin standard solution serial dilutions solution respectively, with paraffin concentration for horizontal ordinate, absorbance is ordinate drawing curve.Preferably, cuvette is quartz colorimetric utensil.
In step (2), testing sample is wimet powder, and described wimet powder is formed by paraffin is coated on hard alloy material surface, and hard alloy material can be cobalt powder and tungsten-carbide powder etc.Detect data more accurately for obtaining, preferably, the quality taking testing sample is accurate to 0.0001g.
" add lytic agent low-grade fever to be separated with paraffin to hard alloy material " and refer to and add lytic agent, heating (under being generally 50 ~ 60 DEG C of temperature) to hard alloy material is separated with paraffin.Lytic agent can be salpeter solution, and preferably, lytic agent is that analytically pure nitric acid and water form by same volume mixed preparing.Preferably, the solid-to-liquid ratio (g/L) of testing sample and lytic agent is 50: 1.
" add organic solvent subsequently, fully shake up " and refer to that adding organic solvent low-grade fever is dissolved in this organic solvent completely to paraffin.Preferably, organic solvent is selected from one or more in phenixin, methenyl choloride, ether, benzene and carbon disulphide.More preferably, organic solvent is the special phenixin of infrared luminosity oil content analyzer, and this phenixin is 2930cm in wave number
-1place's light absorption value is 0.001 ~ 0.03.Repeat to add organic solvent operation once.
" proceed in separating funnel and vibrate, after stratification, take off layer extract and move in volumetric flask, add organic solvent constant volume " refer to by add organic solvent shake up after mixed solution extract, lower floor's extract is the comparatively pure paraffin be purified into.This extraction process number of times is not limit, and is extracted out for ensureing that paraffin in testing sample is as much as possible, and repeatedly can add organic solvent in the mixed solution adding lytic agent, gradation is carried out extracting rear acquisition Duo Fen lower floor extract.Lower floor's extract being moved in volumetric flask, being settled to certain volume by adding organic solvent, for calculating the extension rate of paraffin in testing sample.Preferably, the paraffin after constant volume in per unit mass (mg) testing sample is dissolved in the organic solvent of 1L.
From volumetric flask, pipette mixed solution in a small amount enters in cuvette, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measures absorbance, calculates paraffin content in wimet powder with reference to working curve.
Preferably, step (2) does blank test in company with sample.With blank test sample for reference solution, reagent interference can be eliminated, ensure the accuracy of test result.
The present invention provides the detection method of paraffin content in a kind of wimet powder first, adopts the paraffin in organic solvent extraction separation wimet powder, and measure absorbance on infrared luminosity oil content analyzer, calculate paraffin content with reference to working curve.This detection method short, convenient and safe and reliable results consuming time, can be used in detecting multiple sample simultaneously, with low cost.
Accompanying drawing explanation
Fig. 1 is the working curve diagram of the embodiment of the present invention one.
Embodiment
The following stated is the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.
Embodiment one
A detection method for paraffin content in wimet powder, comprises the following steps:
(1) working curve is set up
Take 0.2500g paraffin standard model, (this phenixin is 2930cm in wave number to dissolving completely to add low-grade fever in the special phenixin of infrared luminosity oil content analyzer
-1place's light absorption value is 0.001 ~ 0.03), move in 250mL volumetric flask, be diluted to scale with phenixin, constant volume mixes, and is mixed with the paraffin standard solution that paraffin concentration is 1000mg/L.Pipette 1.0mL, 2.0mL, 3.0mL and 4.0mL paraffin standard solution respectively in one group of 100mL volumetric flask, be mixed with the paraffin standard solution serial dilutions solution (paraffin concentration is 4 gradients, is respectively 10mg/L, 20mg/L, 30mg/L and 40mg/L) of different paraffin concentration.Being moved into respectively in quartz colorimetric utensil by paraffin standard solution serial dilutions solution, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measure the absorbance of each paraffin standard solution serial dilutions solution respectively, with paraffin concentration for horizontal ordinate, absorbance is ordinate drawing curve, and working curve is shown in Fig. 1, and Fig. 1 working curve equation is: A=0.0159C+0.0103.
(2) paraffin content in wimet powder is detected
Take 1.00g (m
0) testing sample, be accurate to 0.0001g.Be placed in 400mL beaker.Add 10mL water and 10mL analyzes pure nitric acid, low-grade fever is separated to hard alloy material with paraffin.Add 10mL phenixin, fully shake up, repeat this operation once.Proceed in 125mL separating funnel the 20s that vibrates, after stratification, take off a layer extract.Again in the mixed solution adding nitric acid, add phenixin to extract, take off a layer extract.The lower floor's extract collected twice respectively moves into 100mL (V
0) in volumetric flask, add phenixin and be diluted to scale, constant volume mixes.Now, from volumetric flask, divide the solution to be measured getting 5mL in 50mL volumetric flask, be diluted to scale with phenixin, constant volume mixes, and therefrom drawing a small amount of solution subsequently and move in quartz colorimetric utensil, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measuring absorbance is 0.3283, calculates paraffin content in wimet powder with reference to Fig. 1 working curve.
Be calculated as follows the massfraction of paraffin in wimet powder, result represents with %.
In formula:
ρ---on working curve, check in the mass concentration of paraffin, unit is milligrams per liter (mg/L);
V
0---testing sample liquid cumulative volume, unit is milliliter (mL);
M
0---the quality of testing sample, unit is gram (g);
5---point testing sample liquid volume got, unit is milliliter (mL);
50---testing sample liquid divides the mensuration volume after getting constant volume, unit to be milliliter (mL).
Particularly, Fig. 1 working curve equation is: A=0.0159C+0.0103, is calculated the mass concentration ρ of paraffin, be calculated as follows by curvilinear equation:
ρ value substitutes into the massfraction of formulae discovery paraffin:
Effect example
(1) quantitative detecting reliability
In order to verify the reliability of the inventive method, this experiment have employed thermogravimetry to all testing samples simultaneously and the inventive method has carried out control experiment.
In each method, the equal replicate determination of each testing sample 2 times, averages as quantitative experimental data.The control experiment data of thermogravimetry and the inventive method are as table 1.
The control experiment of table 1 thermogravimetry and the inventive method
| Sample number into spectrum | Thermogravimetry wax content (%) | The inventive method wax content (%) | Relative deviation |
| 1 | 1.05 | 1.00 | 4.87％ |
| 2 | 1.03 | 1.02 | 0.98％ |
| 3 | 1.45 | 1.46 | 0.69％ |
| 4 | 1.42 | 1.41 | 0.70％ |
| 5 | 2.02 | 1.98 | 2.00％ |
| 6 | 1.99 | 2.02 | 1.49％ |
| 7 | 2.50 | 2.48 | 0.80％ |
| 8 | 2.45 | 2.46 | 0.41％ |
| 9 | 3.02 | 2.95 | 2.35％ |
| 10 | 2.96 | 2.98 | 0.67％ |
| 11 | 3.96 | 3.99 | 0.75％ |
| 12 | 3.90 | 3.96 | 1.53％ |
Thermogravimetry requires that between twice measurement result, maximum deviation must not be greater than 5% of mean value.As can be known from Table 1, adopt the paraffin content in the inventive method detection wimet powder, compare its relative deviation with thermogravimetry within 5%.This deviation is in allowed limits, is rational deviation, consequently reliably.
For verifying the accuracy of testing result further, devise mark-on recovery test.Mark-on recovery test is: the paraffin standard substance adding known quantity in wimet powder, adds paraffin content and be respectively 0.01g, 0.02g and 0.03g, be numbered 1#, 2#, 3#.Measure according to the inventive method, it the results are shown in Table 2.
Table 2 mark-on recovery test
| Sample name | Sample weighting amount g | Add paraffin amount g | Record paraffin amount g | Recovery % |
| 1# | 1.0 | 0.01 | 0.0098 | 98 |
| 2# | 1.0 | 0.02 | 0.0205 | 102.5 |
| 3# | 1.0 | 0.03 | 0.0305 | 101.3 |
As seen from Table 2, recovery of standard addition, 98% ~ 103%, shows that its testing result is accurately.
(2) linear relationship, the recovery and precision
Paraffin standard solution is prepared the paraffin standard solution serial dilutions solution of different paraffin concentration, use 4cm quartz colorimetric utensil sample introduction, take absorbance as horizontal ordinate, paraffin concentration is ordinate, drawing curve, and its linearly dependent coefficient is 0.9995.
Add paraffin standard substance in wimet powder, preparation wax content is 1.0%, 2.0% and 3.0% 3 kind of sample, is numbered 1# respectively, 2#, 3#.Measure according to the inventive method, its relative standard deviation is in table 3.
Table 3 sample precision test
From table 2 and table 3, detect the paraffin content in wimet powder by the inventive method, its accuracy and precision are all ideal.
Claims (9)
1. the detection method of paraffin content in wimet powder, is characterized in that, comprise the following steps:
(1) working curve is set up: take paraffin standard model, add low-grade fever in organic solvent extremely to dissolve completely, be mixed with paraffin standard solution, prepare the paraffin standard solution serial dilutions solution of different paraffin concentration subsequently respectively, moving in cuvette, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measure the absorbance of each paraffin standard solution serial dilutions solution respectively, with paraffin concentration for horizontal ordinate, absorbance is ordinate drawing curve;
(2) paraffin content in wimet powder is detected: take testing sample, add lytic agent low-grade fever and be separated with paraffin to hard alloy material, described lytic agent is salpeter solution; Add organic solvent subsequently, fully shake up, proceed in separating funnel and vibrate, after stratification, take off layer extract and move in volumetric flask, add described organic solvent constant volume, from volumetric flask, pipette mixed solution enters in cuvette, is 2930cm in infrared luminosity oil content analyzer wave number
-1place, measures absorbance, calculates paraffin content in wimet powder with reference to working curve.
2. the method for claim 1, is characterized in that, described organic solvent is selected from one or more in phenixin, methenyl choloride, ether, benzene and carbon disulphide.
3. method as claimed in claim 2, it is characterized in that, described organic solvent is the special phenixin of infrared luminosity oil content analyzer, and this phenixin is 2930cm in wave number
-1place's light absorption value is 0.001 ~ 0.03.
4. the method for claim 1, is characterized in that, the quality taking paraffin standard model in described step (1) is accurate to 0.0001g.
5. the method for claim 1, is characterized in that, in described step (1), in paraffin standard solution, the concentration of paraffin is 1000mg/L.
6. the method for claim 1, is characterized in that, in described step (1), the concentration of paraffin standard solution serial dilutions solution is respectively 10mg/L, 20mg/L, 30mg/L and 40mg/L.
7. the method for claim 1, is characterized in that, the quality taking testing sample in described step (2) is accurate to 0.0001g.
8. the method for claim 1, is characterized in that, in described step (2), lytic agent is that analytically pure nitric acid and water form by same volume mixed preparing.
9. the method for claim 1, is characterized in that, in described step (2), the solid-to-liquid ratio g/L of testing sample and lytic agent is 50:1.
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| US5223714A (en) * | 1991-11-26 | 1993-06-29 | Ashland Oil, Inc. | Process for predicting properties of multi-component fluid blends |
| CN1587990A (en) * | 2004-09-24 | 2005-03-02 | 江西师范大学 | Method for analyzing beta-cyclodextrin clathrate compound by Fourier infrared spectrum method |
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