CN104502298A - Method for determining cadmium and trace lead in iron ore - Google Patents
Method for determining cadmium and trace lead in iron ore Download PDFInfo
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- CN104502298A CN104502298A CN201410813789.2A CN201410813789A CN104502298A CN 104502298 A CN104502298 A CN 104502298A CN 201410813789 A CN201410813789 A CN 201410813789A CN 104502298 A CN104502298 A CN 104502298A
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Abstract
The invention discloses a method for determining cadmium and trace lead in an iron ore. The method comprises the following steps: digesting an iron ore sample by virtue of a microwave digestion apparatus, and determining a test solution by virtue of an atomic absorption spectrometer of a graphite furnace, wherein the microwave digestion comprises the following processes: putting dried iron ore into a polytetrafluoroethylene digestion tank, wetting with deionized water, and adding nitromurlatic acid; after sharp reaction is ended to obtain a mixture, putting the mixture into a furnace cavity of the microwave digestion apparatus, setting the digestion temperature to 190 DEG C, the heating time to 20 minutes, and digestion keeping time to 20 minutes; after the digestion is ended, cooling to a room temperature, taking out the digestion tank, and taking out the sample in the tank; and adding water to be in constant volume, so as to obtain a to-be-tested solution of the sample. According to the method, the sample can be completely digested by virtue of a microwave digestion method; the detection result is consistent with those of other methods under the condition that a base modifier is not added; and the method has the advantages of being simple, rapid, and accurate, and is suitable for determination of the cadmium and the trace lead in the iron ore.
Description
Technical field
The invention belongs to physical and chemical inspection technical field, specifically a kind of method measuring cadmium and micro lead in iron ore.
Background technology
Iron ore is as the basic material of steel and iron industry, and mineral composition is various, complex chemical composition, is that trade relations or metallurgical requirements are all very deeply concerned to its component.In iron ore, the poisonous and harmful element such as lead, arsenic, cadmium, mercury, fluorine and chlorine not only affects smelting equipment and product quality, also can pollute surrounding enviroment simultaneously, threatens health of human body.Based on factors such as environmental protection and smelting enterprise's protection smelting equipments, iron and steel industry industry standard formulated the limit standard of harmful elements in iron ore in 2014.In iron ore, the examination criteria of the element such as lead, arsenic is more, mainly contains atomic fluorescence spectrometry, inductively coupled plasma emission spectrography, flame atomic absorption spectrometry, volumetric method, spectrophotometric method, inductively coupled plasma mass spectrometry method etc.In iron ore, the examination criteria Measures compare of cadmium lacks, and mainly contains atomic fluorescence method and ICP-MS method.In the iron ore of other bibliographical information, cadmium element method for measuring also has inductively coupled plasma emission spectrography, voltammetry, atomic absorption spectrography (AAS), inductively coupled plasma mass spectrometry etc.In these methods, ICP-MS method is expensive, and the expense that use procedure produces is too high, produces at home, detects the universal difficulty of enterprise.Although flame atomic absorption method and inductive coupling plasma emission spectrum method instrumentation are simply, the cadmium content in iron ore is lower, adopts these two kinds of method sensitivity not reach requirement.Zhang Li etc. adopt Hg-afs Determination, although detection limit is lower, the preparation of Sulfhydryl Cotton is cumbersome, and process is complicated.At present, the report of cadmium in graphite furnace atomic absorption spectrometry iron ore is not also found.
GFAAS (graphite furnace atomic absorption spectrometry) is the atomizer utilizing graphite material to make the shapes such as pipe, cup, carries out the method for atomic absorption analysis by current flow heats atomization.Due to sample full entry atomization, and avoid the dilution of atomic concentration in flame gas, sensitivity for analysis obtains significant raising, and detectability can reach 10
-6~ 10
-4, than ICP-AES method 1 ~ 2 order of magnitude.For measuring trace metal element, better than other many methods in performance, and analysis and the solid sample Direct Analysis of a small amount of sample can be used for.Compare with atomic fluorescence spectrometry technology with atomic emission spectrum, spectra1 interfer-is few, have better selectivity for tested unit, and thus its application is very extensive.
Summary of the invention
One is the object of the present invention is to provide to have employed micro-wave digestion-GFAAS (graphite furnace atomic absorption spectrometry) to measure the method for cadmium and micro lead in iron ore.
For achieving the above object, the technical solution used in the present invention is:
Measure a method for cadmium and micro lead in iron ore, comprise and clear up iron ore sample with microwave dissolver, then adopt the step that graphite furnace atomic absorption spectrophotometer measures.
In technique scheme:
The process that described microwave dissolver clears up iron ore is:
The solution iron ore sample of oven dry is placed in teflon counteracting tank, soaks with deionized water, then add chloroazotic acid, after vigorous reaction stops, put into microwave dissolver furnace chamber, setting digestion condition is 190 DEG C, and the heating-up time is 20min, clearing up the retention time is 20min, be chilled to room temperature after having cleared up, take out counteracting tank, after sample in tank is taken out, add water constant volume, namely obtains sample liquid to be measured.
Further, if silicone content is higher in ironstone sample, described vigorous reaction adds a small amount of hydrofluorite after stopping.
Further, described iron ore sample is preferably dried under 105 DEG C of conditions.
The process that described graphite furnace atomic absorption spectrophotometer measures is:
Working concentration is 1000 μ L/mL lead, cadmium Standard Stock solutions, be diluted to plumbous standard working solution and cadmium standard working solution that concentration is multiple numerical value respectively, utilize graphite furnace atomic absorption spectrophotometer to measure plumbous, cadmium standard working solution and obtain calibration curve, recycling graphite furnace atomic absorption spectrophotometer measures the iron ore sample after micro-wave digestion, obtains cadmium and plumbous content in iron ore by comparison calibration curve.
Preferably, a series of concentration values of described plumbous standard working solution are: 0mg/L, 2mg/L, 4mg/L, 6mg/L, 8mg/L.A series of concentration values of described cadmium standard working solution are: 0 μ g/L, 0.5 μ g/L, 1 μ g/L, 2 μ g/L, 4 μ g/L.
Preferably, instrument parameter when described graphite furnace atomic absorption spectrophotometer measures is:
Cadmium: wavelength 228.8nm, slit 0.7nm, lamp current 4.0mA; Baking temperature 85 ~ 120 DEG C, drying time 25s; Ashing temperature 500 DEG C, ashing time 20s; Atomization temperature 1500 DEG C, atomization time 5s; Burn residual temperature 2450 DEG C, burn residual time 3s; Zeeman correcting background, measures peak area; Take high-purity argon gas as graphite furnace blanket gas, flow 1.8L/min; Sample size then with 20 μ L for the best;
Plumbous: wavelength 217.0nm, slit 0.7nm, lamp current 2.0mA; Baking temperature 85 ~ 130 DEG C, drying time 25s; Ashing temperature 650 DEG C, ashing time 25s; Atomization temperature 1500 DEG C, atomization time 5s; Burn residual temperature 2450 DEG C, burn residual time 3s; Zeeman correcting background, measures peak area; Take high-purity argon gas as graphite furnace blanket gas, flow 1.8L/min; Sample size also with 20 μ L for the best.
Compared to the prior art, the present invention has the following advantages:
1, the pre-treatment of ironstone sample adopts microwave digestion technology, has gathered the performance of high-pressure digestion and microwave fast heating, has sample and decomposes quick, complete, simple to operate, volatile element loss is little, and reagent consumption is few, pollute few, blank low, the distinguishing features such as analysis cost is low;
Have employed GFAAS (graphite furnace atomic absorption spectrometry) when 2, measuring cadmium and lead, sensitivity for analysis is high, and amount of samples is few, simple to operate, and compare with atomic fluorescence spectrometry technology with atomic emission spectrum, spectra1 interfer-is few, have better selectivity for tested unit.
Embodiment
Embodiment 1
1.1 key instrument
AA240Z type graphite furnace atomic absorption spectrophotometer (Varian company of the U.S.); PSD120 graphite furnace automatic sampler (Varian company of the U.S.); O2E-05 type cadmium hollow cathode lamp; The plumbous hollow cathode lamp of WB24A type.ETHOS A type microwave dissolver (LabTech company of the U.S.), is equipped with 12 100mL high-pressure digestion tanks.Milli-Q Advantage A10 ultrapure water system (Millipore Corp. of the U.S.): resistivity 18.2M Ω cm.
1.2 main agents
Plumbous, cadmium Standard Stock solutions (national ferrous materials test center): be 1000 μ g/mL, be diluted to different concentration standard working solutions (see table 1) as required.
The concentration of Pb and Cd in table 1 standard working solution
1.3 experimental technique
Take the iron ore sample that 0.5g is dried at 105 DEG C, be placed in 100mL teflon counteracting tank, soak with a small amount of deionized water, add 10mL chloroazotic acid, after vigorous reaction stops, (if silicone content is higher in sample, drip 1mL hydrofluorite), add a cover cover, be placed in rotating disk, put into furnace chamber, connect temperature, pressure transducer.Setting digestion condition is 190 DEG C, and the heating-up time is 20min, and clearing up the retention time is 20min.Be chilled to room temperature after having cleared up, take out counteracting tank, Specimen eliminating liquid in tank is all transferred in 100mL plastics volumetric flask, is diluted with water to scale, shakes up, leave standstill.In company with doing blank assay.Then under selected instrument parameter condition, plumbous cadmium in solution is measured by GFAAS (graphite furnace atomic absorption spectrometry).
The process that graphite furnace atomic absorption spectrophotometer measures is: working concentration is 1000 μ L/mL lead, cadmium Standard Stock solutions, be diluted to plumbous standard working solution and cadmium standard working solution (see table 1) that concentration is multiple numerical value respectively, utilize graphite furnace atomic absorption spectrophotometer to measure plumbous, cadmium standard working solution and obtain calibration curve, recycling graphite furnace atomic absorption spectrophotometer measures the iron ore sample after micro-wave digestion, obtains cadmium and plumbous content in iron ore by comparison calibration curve.
Instrument parameter when graphite furnace atomic absorption spectrophotometer measures is:
Cadmium: wavelength 228.8nm, slit 0.7nm, lamp current 4.0mA; Baking temperature 85 ~ 120 DEG C, drying time 25s; Ashing temperature 500 DEG C, ashing time 20s; Atomization temperature 1500 DEG C, atomization time 5s; Burn residual temperature 2450 DEG C, burn residual time 3s; Zeeman correcting background, measures peak area; Take high-purity argon gas as graphite furnace blanket gas, flow 1.8L/min; Sample size 20 μ L;
Plumbous: wavelength 217.0nm, slit 0.7nm, lamp current 2.0mA; Baking temperature 85 ~ 130 DEG C, drying time 25s; Ashing temperature 650 DEG C, ashing time 25s; Atomization temperature 1500 DEG C, atomization time 5s; Burn residual temperature 2450 DEG C, burn residual time 3s; Zeeman correcting background, measures peak area; Take high-purity argon gas as graphite furnace blanket gas, flow 1.8L/min; Sample size 20 μ L.
1.4 method detection limits, precision, accuracy and the recovery
Under above-mentioned instrument condition of work, draw calibration curve, to blank solution replication 11 times, get 3 times of measurement result standard deviation (s) as detection limit, 10 times of Determination Limit as method.Detection limit that is plumbous and cadmium is respectively 0.25 μ g/g (Pb) and 0.072 μ g/g (Cd).Plumbous and Cadmium detrmination lower limit is respectively 0.83 μ g/g (Pb) and 0.24 μ g/g (Cd).
According to above-mentioned experimental technique, for same sample ore METHOD FOR CONTINUOUS DETERMINATION 11 times, investigate method precision.Plumbous, cadmium relative standard deviation (RSD, n=11) is respectively 0.8% (Pb) and 2.6% (Cd) (see table 2); Select the iron ore that two are different, adopt this method to measure, from table 2 result, consistent with additive method measured value.In sample ore, add isocyatic element to be measured respectively, measure after clearing up process by 1.4 joint experimental techniques, the method recovery is respectively 96.0% (Pb) and 107.3% (Cd) (see table 3), and result is more satisfactory.
Table 2 preci-sion and accuracy is tested
Note: the cooperative experiment sample that same Fe-1, Fe-2 provide for Tianjin Entry-Exit Inspection and Quarantine Bureau, reference value is cooperative experiment median.
The recovery of table 3 method
Experimental result shows, sample can be cleared up completely with microwave dissolver, and when not adding matrix modifier, the method to the testing result of actual sample and the testing result of additive method consistent.This method is simple, quick, accurate, is applicable to plumbous in batch iron ore and Cadmium detrmination.
Claims (7)
1. measure a method for cadmium and micro lead in iron ore, it is characterized in that: comprise with micro-wave digestion counteract appearance iron ore sample, then adopt the step that graphite furnace atomic absorption spectrophotometer measures.
2. method according to claim 1, is characterized in that, the process of described micro-wave digestion iron ore sample is:
The iron ore sample of oven dry is placed in teflon counteracting tank, soaks with deionized water, then add chloroazotic acid, after vigorous reaction stops, put into microwave dissolver furnace chamber, setting digestion condition is 190 DEG C, and the heating-up time is 20min, clearing up the retention time is 20min, be chilled to room temperature after having cleared up, take out counteracting tank, after sample in tank is taken out, add water constant volume, namely obtains sample liquid to be measured.
3. method according to claim 1, is characterized in that, the process that described graphite furnace atomic absorption spectrophotometer measures is:
Working concentration is 1000 μ L/mL lead, cadmium Standard Stock solutions, be diluted to plumbous standard working solution and cadmium standard working solution that concentration is multiple numerical value respectively, utilize graphite furnace atomic absorption spectrophotometer to measure plumbous, cadmium standard working solution and obtain calibration curve, recycling graphite furnace atomic absorption spectrophotometer measures the iron ore sample after micro-wave digestion, obtains cadmium and plumbous content in iron ore by comparison calibration curve.
4. method according to claim 2, is characterized in that: described vigorous reaction adds hydrofluorite after stopping.
5. method according to claim 2, is characterized in that: described iron ore sample is dried under 105 DEG C of conditions.
6. method according to claim 3, is characterized in that:
A series of concentration values of described plumbous standard working solution are: 0mg/L, 2mg/L, 4mg/L, 6mg/L, 8mg/L;
A series of concentration values of described cadmium standard working solution are: 0 μ g/L, 0.5 μ g/L, 1 μ g/L, 2 μ g/L, 4 μ g/L.
7. the method according to claim 3 or 6, is characterized in that, instrument parameter when described graphite furnace atomic absorption spectrophotometer measures is:
Cadmium: wavelength 228.8nm, slit 0.7nm, lamp current 4.0mA; Baking temperature 85 ~ 120 DEG C, drying time 25s; Ashing temperature 500 DEG C, ashing time 20s; Atomization temperature 1500 DEG C, atomization time 5s; Burn residual temperature 2450 DEG C, burn residual time 3s; Zeeman correcting background, measures peak area; Take high-purity argon gas as graphite furnace blanket gas, flow 1.8L/min;
Plumbous: wavelength 217.0nm, slit 0.7nm, lamp current 2.0mA; Baking temperature 85 ~ 130 DEG C, drying time 25s; Ashing temperature 650 DEG C, ashing time 25s; Atomization temperature 1500 DEG C, atomization time 5s; Burn residual temperature 2450 DEG C, burn residual time 3s; Zeeman correcting background, measures peak area; Take high-purity argon gas as graphite furnace blanket gas, flow 1.8L/min.
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| CN105300908A (en) * | 2015-11-10 | 2016-02-03 | 合肥通用机械研究院 | Method for determining trace element lead in centrifugal casting furnace tube and matrix modifier applied thereto |
| CN105548331A (en) * | 2015-12-10 | 2016-05-04 | 内蒙古包钢钢联股份有限公司 | Method for simultaneous determination of multiple trace elements in iron ore |
| CN106290194A (en) * | 2016-08-22 | 2017-01-04 | 常州大学 | A kind of method of cadmium content in direct mensuration electron level diethylene glycol dimethyl ether |
| CN109297914A (en) * | 2018-11-16 | 2019-02-01 | 阿拉山口出入境检验检疫局综合技术服务中心 | A method of using the Zn-ef ficiency content in graphite resolution-atomic absorption spectrometry sulphur |
| CN110161017A (en) * | 2019-06-04 | 2019-08-23 | 深圳市深投环保科技有限公司 | The method for building up and application method of the mathematical model of the spectra1 interfer- coefficient of iron when ICP-OES method measures cadmium |
| CN111537328A (en) * | 2020-04-20 | 2020-08-14 | 湛江海关技术中心 | Pretreatment method for chromium ore by microwave digestion acid melting method and chromium production method |
| CN114280222A (en) * | 2021-12-14 | 2022-04-05 | 万宝矿产有限公司 | Method for batch processing of copper ore samples |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105300908A (en) * | 2015-11-10 | 2016-02-03 | 合肥通用机械研究院 | Method for determining trace element lead in centrifugal casting furnace tube and matrix modifier applied thereto |
| CN105548331A (en) * | 2015-12-10 | 2016-05-04 | 内蒙古包钢钢联股份有限公司 | Method for simultaneous determination of multiple trace elements in iron ore |
| CN106290194A (en) * | 2016-08-22 | 2017-01-04 | 常州大学 | A kind of method of cadmium content in direct mensuration electron level diethylene glycol dimethyl ether |
| CN109297914A (en) * | 2018-11-16 | 2019-02-01 | 阿拉山口出入境检验检疫局综合技术服务中心 | A method of using the Zn-ef ficiency content in graphite resolution-atomic absorption spectrometry sulphur |
| CN110161017A (en) * | 2019-06-04 | 2019-08-23 | 深圳市深投环保科技有限公司 | The method for building up and application method of the mathematical model of the spectra1 interfer- coefficient of iron when ICP-OES method measures cadmium |
| CN110161017B (en) * | 2019-06-04 | 2022-08-23 | 深圳市环保科技集团股份有限公司 | Method for establishing mathematical model of spectral interference coefficient of iron in cadmium determination by ICP-OES method |
| CN111537328A (en) * | 2020-04-20 | 2020-08-14 | 湛江海关技术中心 | Pretreatment method for chromium ore by microwave digestion acid melting method and chromium production method |
| CN114280222A (en) * | 2021-12-14 | 2022-04-05 | 万宝矿产有限公司 | Method for batch processing of copper ore samples |
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