This standard specifies the determination of silicon content by the perchloric acid dehydration gravimetric method. This standard is applicable to the determination of silicon content in silicon-aluminum alloys and silicon-barium-aluminum alloys. Determination range: 4.00% (m/m) ~ 45.00% (m/m). YB/T 178.1-2000 Chemical analysis method for silicon-aluminum alloys and silicon-barium-aluminum alloys Determination of silicon content by the perchloric acid dehydration gravimetric method YB/T178.1-2000 Standard download decompression password: www.bzxz.net

YB/T178.1--2000
Si-Al alloy and Si-Bar-Al alloy are highly effective deoxidation, desulfurization or grain refinement additives. This standard is formulated to match their product standards.
During the formulation of this standard, the classic perchloric acid dehydration weight method was used to conduct comprehensive condition tests, focusing on the selection of flux, the amount of perchloric acid and the improvement of silicon recovery rate. YB/T178 includes the following parts under the general title of "Chemical Analysis Methods for Si-Al Alloys and Si-Bar-Al Alloys", of which this standard is Part 1.
1) Determination of silicon content by perchloric acid dehydration weight method 2) Determination of barium content by barium sulfate weight method
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 method
7) Determination of sulfur content by infrared absorption method
This standard is proposed and managed by the Metallurgical Information Standards Research Institute. This standard was drafted by Shanghai Baosteel Group Corporation. The main drafters of this standard are: Liu Xiaoping, Wang Ronggang, Chen Yuyuan, Song Yuefang65!
1 Scope
Standard of Ferrous Metallurgy Industry of the People's Republic of China Methods for Chemical Analysis of Silicon-Aluminiumalloy and Silicon-Barium-Aluminium Alloy The perchloric acid dehydration-gravimetric methodfor the determination of silicon content This standard specifies the perchloric acid dehydration-gravimetric method for the determination of silicon content. This standard is applicable to the determination of silicon content in silicon-aluminium alloy and silicon-barium-aluminium alloy. Determination range: 4.00% (m/m) ~ 45.00% (m/m). 2 Referenced Standards
YB/T 178. 1—2000
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards: GB/T4010--1994 Taking and preparing samples for chemical analysis of ferroalloys 3 Method Summary
The sample is melted with a mixed flux, acidified with hydrochloric acid, heated with perchloric acid to evaporate and smoke twice, so that silicon generates insoluble silicic acid. After burning, weighing, and hydrofluoric acid treatment, silicon generates silicon tetrafluoride and volatilizes, and then burned and weighed again. The percentage of silicon is calculated based on the difference in mass before and after hydrofluoric acid treatment.
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 Sodium hydroxide.
4.2 Sodium carbonate (anhydrous).
4.3 Sodium peroxide.
4.4 Perchloric acid (p=1.67g/mL).
Hydrofluoric acid (p=1.15g/mL).
Sulfuric acid (1+1) (V/V): dilute with sulfuric acid (o=1.84g/mL) with water. Hydrochloric acid (1+1) (V/V): dilute with hydrochloric acid (o=1.19g/mL) with water. 4.8 Hydrochloric acid (1+9) (V/V): dilute with hydrochloric acid (p=1.19g/ml.) with water. 4.9
Ammonium thiocyanate solution (50g/1.).
4.10 Silver nitrate solution (10g/L). bZxz.net
Approved by the State Bureau of Metallurgical Industry on July 26, 2000, implemented on December 1, 2000
5 Instruments and equipment
YB/T 178.1--2000
Only common laboratory instruments and equipment shall be used in the analysis. 6 Sampling
Sampling shall be carried out in accordance with GB/T4010. The sample shall pass through a 0.125mm sieve and be stored in a sealed dry container for no more than 6 months.
7 Analysis steps
Safety instructions: Usually in the presence of ammonia, organic matter, etc., the emission of perchloric acid fumes may cause an explosion. Hydrofluoric acid can seriously burn the human body, and safety measures should be taken when using it.
7.1 Sample quantity
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Silicon content, % (m/m)
7.2 Blank test
Carry out a blank test along with the sample.
7.3 Determination
Sample amount·g
7.3.1 Place the sample (7.1) in a nickel-crystal containing 2g of sodium hydroxide (4.1) that has been heated and dehydrated in advance and cooled to room temperature, add 1g of sodium carbonate (4.2), mix, heat on an electric furnace until it is semi-molten, remove and cool, then cover with 3g of sodium peroxide (4.3), melt in a high-temperature furnace at 650℃~700℃ for about 10 minutes, until the sample is completely melted. 7.3.2 After the crucible has cooled, place it in a 500mL beaker, cover it with a watch glass, slightly remove the watch glass, slowly add 50mL of hydrochloric acid (4.7), wait for the sintered block to leach out, take it out and wash it with hot water, add 50mL of perchloric acid (4.4), heat and evaporate until the perchloric acid vapor refluxes along the inner wall of the beaker, and continue heating for about 15 minutes.
7.3.2.1 Remove the beaker and let it cool. Add 20mL hydrochloric acid (4.7) and 80mL hot water. Stir to dissolve the soluble salts. Immediately filter into a 500mL beaker with a quantitative filter paper (medium speed) with a small amount of pulp. Scrub the residue in the beaker with a wipe and transfer it to the filter paper. Wash the precipitate and filter paper with hot hydrochloric acid (4.8) until there is no iron ion reaction [check with ammonium thiocyanate solution (4.9)], and then wash with hot water until there is no chloride ion reaction [check with silver nitrate solution (4.10)]. Keep the filter paper and precipitate. 7.3.2.2 Add 10mL perchloric acid (4.4) to the filtrate and washings obtained in 7.3.2.1, heat and evaporate until the perchloric acid vapor refluxes along the inner wall of the beaker and continue heating for 15 minutes. The following is carried out according to 7.3.2.1. 7.3.3 Place the precipitate obtained from 7.3.2.1 and 7.3.2.2 together with the filter paper in a platinum crucible, incinerate at low temperature, burn in a high-temperature furnace at 1000°C for 1 hour, take out and cool slightly, place in a desiccator, cool to room temperature, weigh, and burn repeatedly until constant weight. 7.3.4 Add a small amount of water to moisten the residue, add 4 drops of sulfuric acid (4.6) and 5mL of hydrofluoric acid (4.5), place the platinum crucible on an electric furnace and slowly evaporate until all the sulfur trioxide white smoke is emitted. Burn in a high-temperature furnace at 1000°C for 30 minutes, take out and cool slightly, place in a desiccator, cool to room temperature, weigh, and burn repeatedly until constant weight.
8 Calculation of analysis results
Calculate the mass percentage of silicon according to formula (1): [(ml = m) - (m = m)] × 0. 467 4 × 100Si(%) =
Wherein: mi--
YB/T 178.1.—2000
Mass of precipitate and platinum before hydrofluoric acid treatment, g; Mass of precipitate and platinum crucible after hydrofluoric acid treatment·g; Mass of blank and crucible with sample before hydrofluoric acid treatment, g; Mass of blank and crucible with sample after hydrofluoric acid treatment, g; Mass of sample, g;
Coefficient for converting silicon dioxide into silicon.
Analysis results are 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 2. Table 2
4.00～20.00
>20.00~45.00
10 Test report
The test report should include the following contents:
a) Identification of the test material, laboratory and analysis date; b) The degree of compliance with the provisions of this standard;
c) Analysis results and their expression;
d) Abnormal phenomena observed during the measurement;
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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