GB 18552-2001 Occupational exposure limits for tantalum and its oxides in workplace air

This standard specifies the maximum permissible concentration and time-weighted average permissible concentration of tantalum and its oxides in the air of a workplace and their monitoring and inspection methods. This standard is applicable to all types of industrial enterprises that produce and use tantalum and its oxides. GB 18552-2001 Occupational exposure limits for tantalum and its oxides in the air of a workplace GB18552-2001 Standard download decompression password: www.bzxz.net

GB18552—2001
This standard is formulated based on toxicological experiments, on-site labor hygiene surveys and epidemiological survey data and reference to foreign occupational exposure limits. It is a hygienic standard used for workshop environmental monitoring and health supervision. This standard will be implemented from May 1, 2002. Appendix A of this standard is the appendix to the standard, which is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Hunan Provincial Institute of Labor Hygiene and Occupational Disease Prevention and Control, and the Epidemic Prevention Station of Zhuzhou Cemented Carbide Factory participated in the drafting. The main drafters of this standard are Chen Yuxu and Yin Xiaohua. This standard is entrusted to the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine for interpretation. 697
1 Scope
National Standard of the People's Republic of China
Occupational exposure limit for tantalumand its uxide in the air of workplaceGB 18552-2001
This standard specifies the maximum permissible concentration and time-weighted average permissible concentration of tantalum and its uxide in the air of workplace and their monitoring and inspection methods.
This standard is applicable to all kinds of industrial enterprises that produce and use tantalum and its uxide. 2 Hygiene requirements
The maximum permissible concentration of tantalum and its uxide in the air of workplace (by group) is 10 mg/m3, and the time-weighted average permissible concentration is 5 mg/tm*.
3 Monitoring and inspection methods
The monitoring and inspection methods of this standard adopt iodine green spectrophotometry, see Appendix A (Appendix to the standard). Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on December 4, 2001698
Implementation on May 1, 2002
A1 Principle
GB 18552—2001
Appendix A
(Appendix to the standard)
Iodine green spectrophotometry
Phthium and its oxides in the air are collected with perchloroethylene filter membrane. After ashing, in an acidic solution, palladium ions are complexed with fluoride ions and then react with iodine green to form a purple-blue complex. The complex is extracted with benzene and quantified by colorimetry. A2 Instruments
A2.1 Perchloroethylene filter membrane (dust filter). A2.2 Dust sample clamp and small plastic sampling clamp. A2.3 Dust sampler: flow range (5~30)L/min; air sampler: flow range (0~3)L/min. A2.4 Stoppered colorimetric tube: 20ml*
A2.5 Platinum crucible, alcohol burner.
A2.6 Spectrophotometer
A3 Reagents
The experimental water is deionized water.
A3.1 Potassium pyrosulfate.
A3.2 Citric acid solution: 100g/L..50g/L. A3.3 Sulfuric acid solution: 0.5mol/L, 0.25mol/l. A3.4 Sodium fluoride solution: 1mol/1. (Put in a plastic bottle) A3.5 Iodine green solution: 5.0g/I.
A3.6 Benzene: high-grade pure.
A3.7 Molybdenum pentoxide standard solution: Accurately weigh 0.0500 g of molybdenum pentoxide (Ta2();, 99, 99%) in a platinum flask, add about 3 g of potassium pyrosulfate, and melt on an alcohol burner until transparent; after cooling, add 10 mL of 50/L citric acid solution, heat to dissolve the clot; quantitatively transfer to a 500 mL volumetric flask with 0.25 mol/L sulfuric acid solution and dilute to the scale. This solution is 100 μg/ml. The standard stock solution is stored in a plastic bottle. Before use, dilute with water to a 10/ml molybdenum pentoxide standard solution. A4 Sampling
A4.1 Fixed-point sampling: Place the filter membrane in the dust sampling clip. At the sampling point, use a small dust sampler to collect 100L research gas sample at a flow rate of 20L/min.
GB.18552--2001
A5.3 Drawing of standard curve: Prepare the standard series according to Table A1. Table A1Ta2O, preparation of standard series
Standard solution, ml.
Water, mL
Amount of lead pentadienide (TazO:), pgwww.bzxz.net
Tube u 5m Inject 1ml
Hydrogenation rate bag whole -
GB18552—2001
Test results. During colorimetric analysis, the absorbance slowly decreases due to the color of the organic layer adsorbed by the colorimetric cup, so the colorimetric analysis should be performed as soon as possible after the extract is poured into the colorimetric cup; soaking the colorimetric cup in acetone can improve the stability of the measurement. A7.5 If the content of molybdenum pentoxide in the sample exceeds the linear range of the standard curve, it can be diluted with water and then measured: multiply the dilution factor when calculating.
A7.6 Determine 10g of molybdenum pentoxide (Taz), the following coexisting ions are not disturbed: 20mgCo\+10ngCa2+.1mgCr51500μg Cu\+,Nis+、Mn'+,100μg Hg2+,Cd2+,Fe(total iron),Nbil,20μg Se2t.
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