CN102147372A - Detection method for free chromium in electrical steel coating - Google Patents
Detection method for free chromium in electrical steel coating Download PDFInfo
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- CN102147372A CN102147372A CN 201110008678 CN201110008678A CN102147372A CN 102147372 A CN102147372 A CN 102147372A CN 201110008678 CN201110008678 CN 201110008678 CN 201110008678 A CN201110008678 A CN 201110008678A CN 102147372 A CN102147372 A CN 102147372A
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Abstract
The invention relates to a detection method for the content of free chromium in an electrical steel coating, belonging to the technical field of element content detection. A boiling and washing method is adopted for extracting the free chromium from a surface coating of a steel plate; a spectrophotometric method is used for detection; a detected absorbancy is used for calculating the content of the free chromium in the coating; and the content of free chromium is an important parameter for guiding the production of the electrical steel coating. The detection method has the advantages that the operation is simple and convenient, the detection is fast, and the result is accurate.
Description
Technical field
The invention belongs to constituent content detection technique field, the detection method of free chromium in a kind of electrical steel coatings particularly is provided.
Background technology
Electrical sheet is a kind of important magnetic material, and non-oriented electrical steel is widely used in the iron core of motors such as genemotor, generator, miniature transformer.When making iron core, need continuously the electric steel plate punching to be become the blank of core configuration, fix by the chip edge that welds the some that will fold.In order to reduce eddy current loss, need to apply insulating coating, so that make between each synusia insulated from each other at surface of steel plate.
Coating is last procedure that electrical sheet is produced, the kind of coating, technology and quality will produce significant impact to mutually insulated, tack, punching, weldability and corrosion stability between electrical sheet etc., thereby further influence the iron loss level of electrical sheet itself and even the performance of product.
The cold rolling non-oriented electrical steel surface coating mainly comprises: inorganic coating, organic coating, half organic coating three major types.Producing now and going up widely used chromate+organic resin is half organic coating of principal ingredient, as zinc chromate mentioned in the patents such as the special public clear 50-15013 of Jap.P., U.S. Pat 3909313 or magnesium chromate+emulsion acrylic resin or styrene, acetate emulsion, this kind coating has higher interface resistance, good tack and rust-preventing characteristic, and have good punching performance and a heat resistance, therefore since eighties of last century the seventies until today, still at home and abroad use in a large number in each big electrical sheet production firm.The sexavalent chrome acid group that contains in this kind coating has bigger pollution to environment.But in burning attached reduction process, sexavalent chrome can be reduced into trivalent chromium, thereby reduces the harm to environment greatly.But, cross at reductive agent deficiency, burned-in temperature under the influence of factor such as low, thereby may not being reduced into trivalent chromium, the part sexavalent chrome causes pollution to environment.Various countries and area have all been carried out strict restriction to chromate as the free chromium content of the electrical sheet sexavalence of coating.
But though all there is the method for the free chromium of check in each big electrical sheet factory, method is not quite similar.And along with the maturation of production technology, the free chromic acid of steel mill also remains on very low level.This has also caused certain methods can't detect the micro free chromium that contains in the electrical steel coatings.Therefore, original free chromium detection method is improved, just seemed very necessary with the detection that more adapts to existing electrical steel coatings.
Summary of the invention
The object of the present invention is to provide in a kind of electric steel insulating coating free chromium content detecting method, realized easy, detect the content of free chromium accurately and fast.
Detection step of the present invention is as follows:
(1) steel plate with band coating to be measured laterally is cut into 3～6, as test sample; Get beaker and add 50～100ml distilled water, place and the test portion that shears is put into liquid after boiling on the electric furnace; After boiling 10～25 minutes, beaker is taken off from electric furnace, test portion is pressed from both sides out, clean with distilled water with the bamboo tweezers;
(2) boil after washing lotion is cooled to room temperature above-mentioned, in boiling washing lotion, add the acid mixture of 5～10ml and the developer of 3ml, transfer in the volumetric flask of 100ml, shake up after adding water to scale mark;
(3) with blank reagent solution as reference solution, determination step (2) shakes up solution absorbency in the volumetric flask of back under selected wavelength;
(4) according to (3) the step absorbance of surveying, find corresponding chromium content, and calculate the free chromium content of test sample floating coat from the typical curve of drawing by chromium standard solution.
Principle of work of the present invention is to adopt spectrophotometric method to measure the content of free chromium in the coating.Spectrophotometric method is based on a kind of analytical approach of material to the selectivity absorption of light, and its ultimate principle is a Lambert-Beer's law, and promptly material is directly proportional with thickness, concentration to the absorption of light.
In acid solution, the reaction of sexavalent chrome and diphenylcarbazide generates the aubergine compound, and the depth of color is directly proportional with chromium content, meets Lambert-Beer's law, but so available spectrophotometer measure.
Described acid mixture is the mixed solution of sulfuric acid, phosphoric acid, nitric acid, wherein, and water 330ml, sulfuric acid 60ml, phosphatase 24 5ml, nitric acid 15ml.Order by sulfuric acid, phosphoric acid, nitric acid adds in the entry respectively, and stirs.
Described colour developing liquid is diphenylcarbazide-ethanolic solution of 0.2%, and the preparation method is for dissolving the 0.2g diphenylcarbazide in 100ml ethanol.Be stored in the brown bottle.
In the detection method of free chromium of the present invention, employed blank reagent solution is that the acid mixture of the direct 5～10ml of adding of distilled water and the developer of 3ml are diluted to the resulting solution of 100ml.
In the detection method of free chromium of the present invention, being plotted as of typical curve: get 0,1,2,4,6,8, the chromium standard solution of 10ug, be diluted to 50ml, add the developer of the acid mixture of 5～10ml and 3ml and constant volume respectively behind 100ml, shake up; Under the 540nm wavelength, make reference, measure absorbance separately with blank reagent.Micrograms with chromium is a horizontal ordinate then, and corresponding absorbance is an ordinate, draws and forms typical curve.
Described chromium standard solution is the standard chlorine aqueous acid of 5 μ g/ml.During accurately the pure potassium dichromate 0.1414g of weighing top grade packs the 500ml volumetric flask into, be settled to graticule with distilled water and also fully shake, obtain the storing solution of 100 μ g/ml.From storing solution, pack in the volumetric flask of 100ml, be settled to graticule with distilled water with transfer pipet separatory 5.00ml.Thereby be mixed with the chromium standard solution of 5 μ g/ml.
Described selected wavelength is to get the beaker that 10ml chromic acid standard solution places 100ml with transfer pipet, behind adding reductive agent, the colour developing liquid, uses the distilled water constant volume also to shake up.Use blank reagent solution to do reference solution, use spectrophotometer in 350nm～700nm wavelength coverage, to scan this mixed solution, measure absorbance, and draw absorbance-wavelength curve every 10nm.Get the measurement wavelength of the wavelength at maximum absorption band place as this experiment.
The invention has the advantages that fast detecting is gone on a tour from the content of chromium aborning, instruct the production of electrical steel coatings as an important parameter.And easy and simple to handle, testing result is accurate.
Embodiment
Instrument: 1 of SP-722 type visible spectrophotometer; 4 of cuvettes; 1 on electric furnace; One in 1ml transfer pipet; One in 10ml transfer pipet; 1 of 10ml graduated pipette; 8 in 100ml volumetric flask; 1 in the brown volumetric flask of 100ml; 1 in 500ml volumetric flask; 3 in 1000ml volumetric flask; 1 in 10ml graduated cylinder; 1 in 50ml graduated cylinder
Reagent:
Sulfuric acid, phosphoric acid, nitric acid acid mixture.Wherein, water 330ml sulfuric acid, 60ml phosphoric acid, 45ml nitric acid 15ml.Order by sulfuric acid, phosphoric acid, nitric acid adds in the entry respectively, and stirs.
Diphenylcarbazide-ethanolic solution.The preparation method is for dissolving the 0.2g diphenylcarbazide in 100ml ethanol.
5 μ g/ml chromium standard solutions
Experimental procedure:
1. specimen preparation:
With scissors the non-orientation silicon steel sample (size 30*300mm) of band chromate half organic coating laterally is cut into 5 equal portions.Put into 100ml distilled water with the beaker of 200ml, place and test portion is put into liquid gently after boiling on the electric furnace.After boiling 20 minutes, beaker is taken off from electric furnace, test portion is pressed from both sides out, cleaned with low amounts of water with the bamboo tweezers.Placement is cooled to room temperature.
2. the drafting of typical curve:
According to the form below requires to prepare respectively 7 parts of series standard solution in the 100ml volumetric flask, is diluted with water to scale, shakes up, leave standstill 10min after, go out mensuration absorbance separately with the cuvette of 1cm in the 540nm wavelength.Micrograms with chromium is a horizontal ordinate, and corresponding absorbance is an ordinate, the drawing standard curve.
| Numbering | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Chromium standard solution volume/ml | 0 | 1 | 2 | 4 | 6 | 8 | 10 |
| Chromium content/ug | 0 | 5 | 10 | 20 | 30 | 40 | 50 |
| Acid mixture/ml | 10 | 10 | 10 | 10 | 10 | 10 | 10 |
| Developer/ml | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
3. chromium Determination on content in the test solution
Boil in the volumetric flask that washing lotion is transferred to 100ml cooled.To the acid mixture that wherein adds 10ml and add the 3ml reductive agent, be settled to scale with distilled water then, left standstill after shaking up 3 minutes.As reference solution, under the 540nm wavelength, measure solution absorbency with blank reagent solution.3 parts of replicate determinations.
This method is easy and simple to handle, the accurate and favorable reproducibility of result.Fast detecting is gone on a tour from the content of chromium aborning, instructs the production of electrical steel coatings as an important parameter.
Claims (6)
1. the detection method of free chromium in the electrical steel coatings is characterized in that, detects step and is:
(1) steel plate with band coating to be measured laterally is cut into 3～6, as test sample; Get beaker and add 50～100ml distilled water, place and the test portion that shears is put into liquid after boiling on the electric furnace; After boiling 10～25 minutes, beaker is taken off from electric furnace, test portion is pressed from both sides out, clean with distilled water with the bamboo tweezers;
(2) boil after washing lotion is cooled to room temperature above-mentioned, in boiling washing lotion, add the acid mixture of 5～10ml and the developer of 3ml, transfer in the volumetric flask of 100ml, shake up after adding water to scale mark;
(3) with blank reagent solution as reference solution, determination step (2) shakes up solution absorbency in the volumetric flask of back under selected wavelength;
(4) according to (3) the step absorbance of surveying, find corresponding chromium content, and calculate the free chromium content of test sample floating coat from the typical curve of drawing by chromium standard solution.
2. the detection method of free chromium in a kind of electrical steel coatings according to claim 1, it is characterized in that: described acid mixture is the mixed solution of sulfuric acid, phosphoric acid, nitric acid, wherein, water 330ml, sulfuric acid 60ml, phosphatase 24 5ml, nitric acid 15ml; Order by sulfuric acid, phosphoric acid, nitric acid adds in the entry respectively, and stirs.
3. according to the detection method of free chromium in the described electrical steel coatings of claim 1, it is characterized in that: described developer is diphenylcarbazide-ethanolic solution of 0.2%, and the preparation method is for dissolving the 0.2g diphenylcarbazide in 100ml ethanol.
4. the detection method of free chromium in a kind of electrical steel coatings according to claim 1, it is characterized in that: described chromium standard solution is the standard potassium dichromate aqueous solution of concentration 5 μ g/ml.
5. the detection method of free chromium in a kind of electrical steel coatings according to claim 1 is characterized in that: employed blank reagent solution is that the acid mixture of the direct 5～10ml of adding of distilled water and the developer of 3ml are diluted to the resulting solution of 100ml.
6. the detection method of free chromium in a kind of electrical steel coatings according to claim 1, it is characterized in that: described typical curve is, get 0,1,2,4,6,8, the chromium standard solution of 10ug, be diluted to 50ml, add the developer of the acid mixture of 5～10ml and 3ml and constant volume respectively behind 100ml, shake up; Use blank reagent to make reference down in the 540nm wavelength, measure absorbance separately; Micrograms with chromium is a horizontal ordinate then, and corresponding absorbance is an ordinate, draws and forms typical curve.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102590123A (en) * | 2012-02-17 | 2012-07-18 | 长治学院 | Method for detecting content of bismuth in bismuth potassium citrate medicament |
| CN102721660A (en) * | 2011-09-02 | 2012-10-10 | 仲恺农业工程学院 | Cr in electroplating passivation liquid complex sample6+Novel measuring method |
| CN103543143A (en) * | 2012-07-10 | 2014-01-29 | 东亚Dkk株式会社 | Chromium measurement reagent and method |
| CN111693523A (en) * | 2020-06-22 | 2020-09-22 | 阳新娲石水泥有限公司 | Method for detecting total chromium content in raw materials of cement clinker |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101358921A (en) * | 2008-09-05 | 2009-02-04 | 首钢总公司 | Method for detecting free phosphorus in electrical steel coatings |
| CN101946177A (en) * | 2008-02-21 | 2011-01-12 | 矢崎总业株式会社 | Method for simply quantitatively determining hexavalent chromium |
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2011
- 2011-01-16 CN CN 201110008678 patent/CN102147372A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101946177A (en) * | 2008-02-21 | 2011-01-12 | 矢崎总业株式会社 | Method for simply quantitatively determining hexavalent chromium |
| CN101358921A (en) * | 2008-09-05 | 2009-02-04 | 首钢总公司 | Method for detecting free phosphorus in electrical steel coatings |
Non-Patent Citations (1)
| Title |
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| 《监督与选择》 20080415 陈社勤 碳钢及低合金钢中六价铬的测定 71 20080430 , 第04期 2 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102721660A (en) * | 2011-09-02 | 2012-10-10 | 仲恺农业工程学院 | Cr in electroplating passivation liquid complex sample6+Novel measuring method |
| CN102590123A (en) * | 2012-02-17 | 2012-07-18 | 长治学院 | Method for detecting content of bismuth in bismuth potassium citrate medicament |
| CN103543143A (en) * | 2012-07-10 | 2014-01-29 | 东亚Dkk株式会社 | Chromium measurement reagent and method |
| CN103543143B (en) * | 2012-07-10 | 2017-05-17 | 东亚Dkk株式会社 | Chromium measurement reagent and method |
| CN111693523A (en) * | 2020-06-22 | 2020-09-22 | 阳新娲石水泥有限公司 | Method for detecting total chromium content in raw materials of cement clinker |
| CN111693523B (en) * | 2020-06-22 | 2022-04-19 | 阳新娲石水泥有限公司 | Method for detecting total chromium content in raw materials of cement clinker |
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Application publication date: 20110810 |