This standard specifies the determination of barium content by barium sulfate gravimetric method. This standard is applicable to the determination of barium content in silicon-barium-aluminum alloys with strontium content ≤ 0.20% (m/m). Determination range: 5.00 (m/m) ~ 20.00% (m/m) YB/T 178.2-2000 Chemical analysis method for silicon-aluminum alloys and silicon-barium-aluminum alloys Determination of barium content by barium sulfate gravimetric method YB/T178.2-2000 Standard download decompression password: www.bzxz.net

YB/T 178. 2—2000
Silicon-aluminum alloy and silicon-barium-aluminum alloy are highly effective deoxidation, desulfurization or grain refinement additives. This industry standard is formulated to match its product standards.
This standard was comprehensively tested during the formulation process, focusing on the precipitation conditions of barium sulfate, the conditions for the alkali fusion decomposition of acid-insoluble residues and the conversion of barium sulfate, as well as the upper limit of strontium content in the sample. YB/T178 includes the following parts under the general title of "Chemical Analysis Methods for Silicon-Aluminum Alloys and Silicon-Barium-Aluminum Alloys", of which this standard is Part 2.
1) Determination of silicon content by weight method using perchloric acid dehydration 2) Determination of barium content by weight method using barium sulfate
3) Determination of aluminum content by EDTA titration
4) Determination of manganese content by sodium periodate spectrophotometry 5) Determination of phosphorus content by phosphomolybdenum blue spectrophotometry 6) Determination of carbon content by infrared absorption
7) Determination of sulfur content by infrared absorption
This standard is proposed and managed by the Information Standards Research Institute of the Ministry of Metallurgy. The drafting unit of this standard is Xinyu Iron and Steel Co., Ltd. The main drafters of this standard are You Youshen, Zhang Shuiju, Huang Jing, Zeng Bo, and Fu Zhijun. 658
Standard of the People's Republic of China for Ferrous Metallurgy Industry Methods for Chemical Analysis of Silicon-Aluminum Alloy andSilicon-Barium-Aluminium Alloy The barium sulphate gravimetricmethod for the determination of barium content1Scope
This standard specifies the determination of barium content by barium sulfate gravimetricmethod. This standard is applicable to the determination of barium content in silicon-barium-aluminum alloys with strontium content ≤ 0.20% (m/m). Determination range: 5.00% (m/m) ~ 20.00% (m/m), 2Referenced standards
YB/T 178.2-2000
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T4010--1994 Collection and preparation of samples for chemical analysis of ferroalloys 3 Method Summary
The sample is decomposed with nitric acid and hydrofluoric acid, and fluorine is driven out by fuming with perchloric acid. Iron, aluminum, calcium, etc. are masked with EDTA, and barium is precipitated with sulfuric acid. After filtering and burning, it is melted with a mixed flux and the molten block is leached with water. After dissolving the precipitate in hydrochloric acid, barium is precipitated with sulfuric acid, filtered, burned, weighed, and burned repeatedly until constant weight.
4 Reagents and materials
In the analysis, unless otherwise specified, only recognized analytical reagents and distilled water or water of equivalent purity are used. 4.1 Anhydrous sodium carbonate.
Potassium carbonate.
4.3 Mixed flux: Anhydrous sodium carbonate (4.1) and potassium carbonate (4.2) are mixed in a ratio of 1:1. 4.4
Nitric acid (p=1.42g/ml).
4.5 Hydrofluoric acid (o=1.15g/mL).
5 Perchloric acid (p=1.67g/ml).
Hydrochloric acid (1+1) (V/V).
4.8 Hydrochloric acid (1+3) (V/V).
4.9 Hydrochloric acid (2+98) (V/V).
4. 10 Sulfuric acid (1+9) (V/V).
4.11 Sulfuric acid (2+998) (V/V).
4. 12 Ammonia water (1+1) (V/V). bzxz.net
Approved by the State Bureau of Metallurgical Industry on July 26, 2000, implemented on December 1, 2000
YB/T 178.2—2000
4.13 Disodium ethylenediaminetetraacetic acid (EDTA) solution (80 g/L). 4.14 Sodium carbonate solution (10 g/L).
4.15 Silver nitrate solution (1 g/L).
4.16 Nitride solution (100 g/1).
4.17 Methyl orange indicator (1 g/L).
5 Instruments and equipment
Only common laboratory instruments and equipment shall be used in the analysis. 6 Sample preparation
Sample preparation shall be carried out in accordance with the provisions of GB/T4010. The sample shall pass through a 0.125 mm sieve and be stored in a sealed dry container for 6 uses.
7 Analysis steps
Safety instructions: Usually in the presence of ammonia, organic matter, etc., the emission of pernitrogenous acid fumes may cause an explosion. Hydrofluoric acid can severely burn the human body, and safety measures should be taken when using it.
7.1 Sample quantity
Weigh 0.50g of sample, accurate to 0.0001g. 7.2. Blank test
Perform a blank test with the sample.
7.3 Determination
7.3.1 Place the sample (7.1) in a 250mL polytetrafluoroethylene beaker (or platinum III), add 10mL nitric acid (4.4), slowly add 3mL~5mL hydrofluoric acid (4.5) to decompose the sample until there is no red-brown smoke, and heat at low temperature to dissolve the sample. Blow water on the wall of the beaker. Add 10mL perchloric acid (4.6), and heat at low temperature to evaporate until it is almost dry. Remove and cool slightly, add 10ml hydrochloric acid (4,7), and heat to dissolve the salts. 7.3.2 Transfer the solution (7.3.1) to a 400mL beaker and boil until the test solution is clear. Add 20mL of ETA solution (4.13). Dilute to 200mL~220ml with hot water and heat to boil. Add 2~3 drops of methyl orange indicator (4.17), neutralize with nitrogen water (4.12) until the solution changes from orange to yellow, and then adjust to orange with hydrochloric acid (4.8) with an excess of 2mL. 7.3.3 Heat the test solution to boiling, remove, and add 10mL of sulfuric acid (4.10) dropwise while stirring, heat to a slight boil for 5min, keep warm for 30min, and let stand for more than 2h.
7.3.4 Filter with slow quantitative filter paper, wash the beaker with sulfuric acid (4.11), wash the precipitate and filter paper 6 to 8 times, and then wash with water until there is no chloride ion. Use silver nitrate solution (4.15) to test). Discard the filtrate. 7.3.5 Transfer the precipitate and filter paper into platinum, incinerate at low temperature, and place in a high-temperature furnace of 800℃～850℃ for 20min. Take it out and cool it. Add 5g～7g mixed flux (4.3), mash and stir, and then cover with 1g～2g mixed flux (4.3). Melt in a high-temperature furnace of 800℃ for 10min, take it out and cool it slightly, put it in a 400mL beaker pre-filled with 80mL hot water, and heat it. Wash the crucible and take it out. 7.3.6 Under boiling state, crush the frit with a glass rod until it is completely dispersed, and cool it to room temperature. Filter with slow quantitative filter paper, wash the beaker 34 times with sodium carbonate solution (4.14), wash the precipitate and filter paper until there is no sulfate ion. Take a small amount of filtrate, acidify with hydrochloric acid (4.7), boil until bubbles appear, and then add barium chloride solution (4.16) to check. Discard the filtrate. 7.3.7 Dissolve the precipitate in the original beaker with 40ml hot hydrochloric acid (4.8), and then wash the filter paper 6~8 times with hot hydrochloric acid (4.9). 7.3.8 Add 5mL of DTA solution (4.13) to the test solution, dilute to 200ml~220mL with hot water, and heat to boiling. Add 2~~3 drops of methyl orange indicator (4.17), neutralize with ammonia water (4.12) until the solution changes from red to yellow, and then adjust to red with hydrochloric acid (4.8), and add 2ml excess.
7.3.9 The following operations are carried out in accordance with 7.3.3 to 7.3.4. 7.3.10 Transfer the precipitate and the filter paper into a porcelain crucible of constant weight, dry and ashed, and burn in a high-temperature furnace at 800℃~850℃ for 30min. 660
YB/T 178.2—2000
Take out and cool to room temperature in a desiccator. Weigh and repeat the burning until constant weight is reached. 8 Calculation of analysis results
Calculate the mass percentage of barium according to formula (1): [(m2 = ml) - (m4 = m)) × 0.5884 × 100Ba(%) =
Wherein: ml\—mass of the crucible, g;
m2 --mass of the crucible and barium sulfate, g;
m3—mass of the crucible in the blank test, g;
m.—mass of the crucible and barium sulfate in the blank test, g; m
sample weight·g
0.5884—conversion factor for converting barium sulfate to barium sulfate. The analysis results should be expressed to two decimal places. 9 Allowable difference
The difference between two independent analysis results should not be greater than the allowable difference listed in Table 1. Table 1
5.00-10.00
>10.00 ~ 20.00
10 Test report
The test report shall include the following contents:
a) information on identification of the test material, laboratory and analysis date;
b) degree of compliance with the provisions of this standard;
c) analysis results and their expression;
d) abnormal phenomena observed during the determination;
e) operations that may affect the analysis results but are not included in this standard, or optional operations. Xu
%(m/m)
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