GB/T 5124.4-1985 Chemical analysis methods for cemented carbide - Peroxide photometric method for determination of titanium content
Some standard content:
National Standard of the People's Republic of China
Chemical analysis methods of hardmetals
The photometric peroxide method for the determination of titanium contentUDC669.018.25
: 543.42 : 546
GB 5124.4—85
This standard is applicable to the determination of titanium content in mixed powder of carbide and bonding metal (without lubricant and bonding agent) and pre-sintered or sintered hardmetals of all grades. Determination range: above 0.20%. This standard is not in compliance with GB1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". This standard is equivalent to the international standard IS04501-1978 "Cemented Carbide-Determination of Titanium-Peroxide Photometric Method". 1 Method Summary
In sulfuric acid medium, titanium and hydrogen peroxide form a yellow pertitanic acid complex, and its absorbance is measured at a wavelength of 420nm by a ten-fold photometer.
Under the specified conditions, all elements that form or form colored complexes with hydrogen peroxide will interfere. For example, vanadium and molybdenum will interfere with the determination quantitatively, and correction can be made if the content of each is less than 5% (m/m). 2bzxZ.net
Ammonium chlorhydride.
Ammonium sulfate.
Sodium ammonium sulfite.
Citric acid solution; dissolve 300g of citric acid in 700l of water. 2.5
Perchloric acid (specific gravity 1.54 or specific gravity 1.67). Sulfuric acid (specific gravity 1.84).
Sulfuric acid (1 + I).
Hydrogen peroxide (specific gravity 1,10).
Oxyfluoric acid (specific gravity 1.12).
Nitric acid (specific gravity 1.42).
Titanium standard solution: Prepared with metallic titanium or titanium dioxide. 2.11.1 Preparation of titanium standard solution with titanium dioxide Weigh titanium oxide calculated to contain 0.2500g of titanium, place in a 200ml conical flask, add 10g of ammonium sulfate (2.2) and 10ml of sulfuric acid (2.6), cover the conical flask, heat to near boiling until the oxide is completely dissolved, and cool. Add 1ml of hydrogen peroxide (2.8) in batches, mix well, add about 50ml of water, transfer to a 250ml volumetric flask, add 25ml of sulfuric acid (2.7), cool to room temperature, dilute with water to the mark, and mix approx. 1ml of this solution contains 1mg of titanium.
Instructions for use: No lubricant in the international standard. Issued by the National Bureau of Standards on April 24, 1985
Implemented on February 1, 1986
: 2.11.2 Preparation of titanium standard solution with titanium metal 0GB 5124. 4--85
Weigh about 0.25g of titanium metal, accurate to 0.0001g, and place in a 1200ml conical flask. Add 30ml of water and 20ml of sulfuric acid (2.7), cover the conical flask, heat slowly and continuously add water to keep the volume constant until the metal is completely dissolved, and cool. Add about 11 hydrogen peroxide (2.8) to chlorinate the titanium, mix, heat and evaporate the water to the bottom, and cool. Add 10g of ammonium sulfate (2.2), heat slowly until the metal deposits on the wall of the conical flask are completely dissolved, and cool. Add about 50 ml of water, transfer to a 250 ml volumetric flask, add 25 ml of sulfuric acid (2.7), cool to room temperature, dilute to scale with water, and mix. Calculate the concentration of titanium in the solution (g/m1). 8
Spectrophotometer or photoelectric colorimeter.
In a mortar that will not change the sample composition, grind the laboratory sample into a powder and pass it through a 0.18 mm sieve. 5 Analysis steps
5.1 Safety measures
When using perchloric acid, it is necessary to avoid contact between perchloric acid and organic matter. 5.2
Quantity of determination
When measuring, two or three samples should be weighed for determination. 5.3
Sample quantity
Weigh the sample according to Table 1.
10 ~30
Sample, g
Vacuum volume, tml
Note: When the concentration of the colorimetric blood is about 17g/250ml, the unit light intensity should be plotted. 5.4 Determination
5.4.1 Sample
Colorimetric blood volume, em
Put the sample (5.3) in a 250ml beaker, add 5g ammonium sulfate (2.2) and 10ml sulfuric acid (2.6), cover with agricultural blood, heat to boiling, and completely dissolve.
Another sample dissolution method: Put the sample (5.3) in platinum blood, add 10ml water, 5ml chlorofluoric acid (2.9), cover with polyolefin surface IIIL or platinum surface blood, heat to about 80℃, add nitric acid (2.10) until the sample is completely dissolved, remove and cool. Add 10 ml sulfuric acid (2.6) and 5 g ammonium sulfate (2.2), heat the sulfuric acid fumes, and cool. If there are any undissolved particles or carbonaceous materials remaining, cool the solution to below 100°C, carefully add 1 ml perchloric acid (2.5), heat to 40°C, and then cool to room temperature. Instructions for use: Prepare titanium standard solution. International standards use high-purity metallic titanium or titanium dioxide. All impurities greater than 0.01% (m/m) are analyzed. 178
5.4.2 Preparation of analytical solution
GB 5124, 4-—85
Add 1 ml hydrogen peroxide (2.8) in batches and mix well. Add 30 ml citric acid solution (2.4) in batches while stirring, and add 40 ml water.
Select a volumetric flask of appropriate volume according to Table 1, and then perform the following operations: 5.4.2.1 Use a 250ml volumetric flask
Transfer the solution into a 250ml volumetric flask, add 25ml sulfuric acid (2.7), dilute with water to the mark, mix well, and cool to room temperature. Add 1ml hydrogen peroxide (2.8), mix well, dilute with water to the mark, and mix well. 5.4.2.2 Use a 500ml volumetric flask
Transfer the solution into a 500ml volumetric flask, add 30ml citric acid solution (2.4), 50ml sulfuric acid (2.7), dilute with water to the mark, mix well, and cool to room temperature. Add 2 m1 hydrogen peroxide (2.8, mix well, dilute with water to the mark, mix well. 5.4.3 Preparation of reference solution
Place about 30ml of the color-developed solution (5.4.2) in a 50ml beaker, add about 0.2g of sodium bisulfite (2.3) to fade the solution. If necessary, add sodium oxysulfite (2.3). 5.4.4 Measurement of absorbance
Select a cuvette with an appropriate light path. Use the same or paired colorimetric blood, take the reference solution (5.4.3) as a reference, and measure at a spectrophotometric wavelength of 420nm 6.4.5 Elimination of interference
5.4.5.1 Elimination of interference of vanadium-+
Put 30ml of the solution (5.4.2) after color development in a 50ml beaker, add about 0.3g of ammonium bifluoride (2.1) to destroy the colored complex of titanium, and the remaining color after 3 minutes is the color of vanadium. Using the reference solution (5.4.3) as a reference, measure the absorbance of vanadium at a wavelength of 420nm with a ten-fold photometer. And subtract the absorbance of vanadium from the absorbance of the vanadium-titanium complex. 5.4 .5.2 Elimination of molybdenum interference
The color of the peroxide complex is pale and cannot be eliminated by chemical methods. The correction value can be calculated based on the amount of molybdenum. Usually at 420nm, 1% (m/m) of titanium in the sample is equivalent to about 0.08% (m/m). However, the calibration value must be determined using the spectrophotometer used for measurement.
5.5 Drawing of the working curve
Pipette 0.00, 3.00, 6.00, 9.00, 12.00, 15.00ml of titanium standard solution (2.11) and place In a set of 200ml conical flasks, add 5g ammonium sulfate (2.2) and 10ml sulfuric acid (2.6), add 1ml hydrogen peroxide (2.8) in batches, and mix. Add 30ml citric acid solution (2.1) in batches while shaking, add 40ml water, and proceed as per 5.4.2.1 (or 5.4.2.2) and 5.4.35.4.4. Draw a curve with titanium content as the horizontal axis and absorbance as the vertical axis. B. Calculation of analysis results
Calculate the percentage of titanium according to the following formula,
Ti(%) =
ml×100
--corresponding titanium amount found on the working curve, g: formula ft. m,--
sample amount, g.
Tolerance
The extreme difference of one or three independent determination results should not be greater than the tolerance listed in Table 2: Adoption instructions: ① The international standard is to add about 0.1g ammonium bifluoride. ②For the provisions of international standards, see Appendix A (Supplement). 179
0.20~ 5.00
5.00 ~ 8.00
>9.00~15.00
GB 5124.4-85
The allowable difference between two independent determination results
The arithmetic mean of the qualified determination values shall be the final result. 180
The allowable difference between three independent determination results
A.1 Calibration
GB 5124.4--B5
Appendix A
Provisions of international standards on drawing working curves and calculating analytical results (Supplement)
Determine the slope of the absorbance-titanium curve, that is, the absorbance when the titanium concentration in the colorimetric solution is 1.0mg/250ml using a 1cm optical path colorimetric blood. For example:
Pipette 0.00, 5.00, 10.00, 15.00 ml titanium standard solution (2.11) into eleven groups of 200 ml conical flasks, add 5 g ammonium sulfate (2.210 ml sulfuric acid (2.6) respectively, add 1 ml hydrogen peroxide (2.8) in batches, and mix well. Add 3D ml citric acid solution (2.4) in batches while shaking, and add 40 ml water. The following is carried out according to 5.4.2.1 (or 5.4.2.2) and 5.4.3~5.4.4. A.2 Calculation of analysis results
Calculate the percentage of titanium according to the following formula:
Ti (%) =
Wherein:
-absorbance of the amount of titanium contained in the sample:
volume of the solution after color development, 1;
slope of the absorbance-titanium curve;
colorimetric blood diameter, cm#
sample volume, wu.
Additional remarks:
This standard was proposed by China National Metal Industry Corporation. This standard was drafted by Zhuzhou Cemented Carbide. The main drafters of this standard are Mao Guoxing and Zheng Jishen. Energy
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