This standard specifies the maximum permissible concentration of magnesium oxide (smoke) in workshop air and its monitoring and inspection methods. This standard applies to all types of enterprises that produce and use magnesium oxide. GB 16195-1996 Hygienic Standard for Magnesium Oxide (Smoke) in Workshop Air GB16195-1996 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Health standard for magnesium oxide (fume) in the air of workplace
1 Subject content and scope of application
This standard specifies the maximum allowable concentration of magnesium oxide (fume) in the air of workplace and its monitoring and inspection methods. This standard applies to all types of enterprises that produce and use magnesium oxide. 2
Health requirements
The maximum allowable concentration of magnesium oxide (fume) in the air of workplace is 10mg/m2. 3 Monitoring and inspection methods
GB16195-1996
The monitoring and inspection methods of this standard adopt the Dadan yellow colorimetric method, see Appendix A or the atomic absorption spectrometry method, see Appendix B. 4 Supervision and implementation
Health and epidemic prevention agencies at all levels are responsible for supervising the implementation of this standard. Approved by the State Administration of Technical Supervision on April 3, 1996, and implemented on September 1, 1996
A1 Principle
GB 16195-
—1996
Appendix A
Dadan Yellow Colorimetric Method
(Supplement)
In an alkaline solution of pH 12, the generated magnesium hydroxide colloid adsorbs Dadan Yellow to show orange-red color. The color depth of the solution is proportional to the magnesium ion concentration within a certain range. The detection limit of this method is 1.5μg magnesium oxide/25mL. A2 Apparatus
A2.1 Sampling clamp.
A2.2 Filter material: microporous filter membrane, pore size 0.8μm. A2.3 Vacuum pump.
A2.4 Flowmeter, 0～10L/min.
Conical flask, 50ml.
A2.6 Electric heating plate.
Colorimetric tube with stopper, 25ml.
A2.8 Spectrophotometer.
A3 Reagents
A3.1 0.5% Dadan yellow stock solution: weigh 0.5g Dadan yellow, add water to 100ml, put in a brown bottle, and store in a refrigerator at 4℃. Dilute to 0.005% solution before use.
A3.2 0.5% polyvinyl alcohol solution, heat in a beaker with constant stirring to dissolve. A3.3 0.01% calcium carbonate solution: weigh 0.01g calcium carbonate, add about 10ml water and a few drops of concentrated hydrochloric acid, shake to dissolve, and add water to 100ml.
A3.4 10% triethanolamine stock solution: measure 10ml triethanolamine, add water to 100ml, and mix well. A3.51% triethanolamine working solution: Take 10% triethanolamine stock solution and dilute it with water. A3.60.1% citric acid solution.
A3.71mol/L sodium hydroxide solution.
A3.81:9 perchloric acid-nitric acid mixed digestion solution. A3.9 Magnesium oxide stock solution: Accurately weigh 0.1g magnesium oxide and place it in a 50mL conical flask, add 5mL1:9 perchloric acid-nitric acid mixed digestion solution, heat and digest on a hot plate until white precipitate is seen, and dilute the precipitate to 100mL with deionized water. 1mL of this solution = 1mg magnesium oxide.
A3.10 Standard application solution: 1mL15ug magnesium oxide. Take 1.5mL of the above magnesium oxide stock solution and dilute it to 100mL with water (freshly prepared before use).
A4 Sampling
Fix the microporous filter membrane on the sampling clamp and draw 50-100L of air at a speed of 5-10L/min. A5 Analysis Steps
A5.1 Sample Treatment
GB 16195--1996
Place the sampling filter membrane in a 50mL conical flask (also as a blank), add 5mL of 1:9 perchloric acid-nitric acid mixed digestion solution. Heat and digest on a hot plate (if the digestion solution is insufficient, add 2mL) until a white precipitate is seen. Remove and cool, dissolve with deionized water, transfer all into a 25mL colorimetric tube, add water to the 25mL mark, and mix well. A5.2 Sample Analysis
Take 0.1-10mL of the above sample solution into a 25mL colorimetric tube. If it is less than 10mL, add water to 10mL. The following operations are carried out according to the standard tube (see Table A1).
Add 0.5mL 0.1% citric acid solution and 1.0mL 1% triethanolamine solution to each sample and standard tube, mix well, add 2.0mL 0.5% polyvinyl alcohol solution, 5ml 0.005% Dadan yellow solution, 2.0mL 1mol/L sodium hydroxide solution, and add water to 25mL. Cover the stopper and shake for half a minute, and measure at a wavelength of 545nm with a 5cm colorimetric cup. Table A1 Standard tube
Standard solution, ml1
0.01% calcium carbonate, ml.
Add water to, ml.
Magnesium oxide content·ug
A6 Calculation
Where: X-magnesium oxide concentration in air, mg/m2; magnesium oxide content in sample, ug;
V. ——gas sampling volume under standard conditions, L. 2
Appendix B
Atomic absorption spectrophotometry
(Supplement)
B1 Principle
(Al)
The magnesium and its compound dust or smoke in the air is collected on the filter material, digested by a mixture of perchloric acid and nitric acid, and then passed through an air-acetylene flame to form magnesium vapor. The absorption value is measured at a wavelength of 285.2nm and compared with the standard series for quantification. The sensitivity of this method is 0.0015μg/mL.
B2.1 Sampling clip.
B2.2 Filter material: microporous filter membrane, pore size 0.8μm; or perchlorethylene filter membrane. B2.3 Vacuum pump.
B2.4 Flowmeter, 0~10L/min.
B2.5 Conical flask 50mL.
B2.6 Electric heating plate.
B2.7 Stoppered colorimetric tube, 10 ml.
GB 16195-1996
B2.8 Atomic absorption spectrophotometer: equipped with acetylene-air flame burner and hollow cathode magnesium lamp or tungsten magnesium lamp. B3 Reagents
B3.1 Nitric acid (superior grade).
B3.2 Perchloric acid (superior grade).
B3.31:9 Perchloric acid-nitric acid mixed digestion solution. B3.4 Magnesium standard solution: Accurately weigh spectrally pure magnesium powder or its salt, dissolve it in nitric acid to prepare 1mg/mL 1mol/L nitric acid solution, and then dilute this solution with 0.5mol/L nitric acid to 5μg/mL magnesium standard solution. B3.5 Deionized water (resistance 60×104α·cm or more). B3.6 Strontium chloride (or lanthanum chloride) aqueous solution: prepare 1ml. containing 25mg strontium (superior grade pure) or. B4 Sampling
Place the microporous filter membrane or dust-detecting membrane in the sampling clamp and clamp it tightly. Use the sampler to sample more than 50L at a speed of 5-101./min. B5 Analysis steps
Place the sampled filter material in a 50mL conical flask, add 5mL of 1:9 perchloric acid-nitric acid mixed digestion solution and digest it on a hot plate with a slow fire (if using a dust-detecting membrane, add 10mL of 1:4 mixed digestion solution and cover the pot upside down). Digest until the solution is colorless and transparent, then heat it strongly until all the thick white smoke comes out, then remove it (do not evaporate it to dryness), cool it, add a little deionized water, and wash the conical flask several times. Transfer the entire amount into a colorimetric tube, add 1mL of strontium chloride aqueous solution, and dilute to the 10mL mark. At the same time, make 3 blank controls for the filter material, and prepare standard tubes according to Table B1: Prepare standard tubes in Table B1
Standard solution, mL
Strontium chloride solution
Add 0.5mol/L nitric acid
Magnesium concentration, μg/mL
Add 1mL to each tube
to 10mL scale
Measure the absorption value according to the best conditions of the instrument, but the wavelength should be selected at 285.2nm. The calculation formula is as follows: Vc
X = 1. 65
Where: X-bZxz.net
Magnesium oxide concentration in the air, mg/m~;
C-magnesium concentration in the standard curve, μg/mL;
V-dilution volume, mL;
V. -sampling volume under standard conditions, L.
B6 Notes
The standard curve series can be adjusted appropriately according to the concentration on site. 120
·(B1)
Additional Notes:
GB16195-1996
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard is drafted by the Sichuan Provincial Institute of Labor Hygiene and Occupational Disease Prevention and Control. The main drafters of this standard are Wang Dingguo and Wu Zengshu. This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases, Chinese Academy of Preventive Medicine, the technical unit entrusted by the Ministry of Health. 421
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