There are many types of dust in the production environment of the power and coal industries, mainly including silicon dust, coal dust, boiler dust, asbestos dust, cement dust, welding fumes, etc. Its characteristics are that the content of free silica in the dust is high, and the dispersion of the dust is also relatively high, which is mostly respiratory dust. Therefore, it poses a greater risk to personnel exposed to dust. According to the physical and chemical properties of productive dust, the concentration in the air, the amount of dust entering the human body, and the affected areas, the hazards produced also vary, mainly including respiratory diseases such as rhinitis, pharyngitis, tracheitis, bronchitis, etc. The Chinese government, as well as the power and coal industries, attach great importance to dust prevention work. Therefore, strengthening the detection of free silica content in dust is a very important and urgent task. In the past, the detection of free silica content in dust was carried out using the "pyrophosphate gravimetric method" specified in the "Method for Determination of Dust in Workplace Air" (GB5748-85). This method has a series of problems such as complex operating steps, a wide variety of reagents used, long detection cycles, poor accuracy, and strict laboratory conditions, which make it difficult to meet the requirements of on-site batch testing. In order to improve the accuracy of detection and achieve the purpose of batch detection, a FC-2000D free silica analyzer for dust has been specially developed to detect the content of free silica in dust. To meet the needs of different customers, the FC-3000D free silica analyzer for dust has also been launched (with imported spectrometer as the main unit)

Considering the accuracy and speed of instrument testing, FC-4000D has been specially introduced based on FC-2000D, with indicators and performance comparable to imported instruments. The testing speed has been increased from the original ten minutes per sample to ten seconds. Improve testing accuracy by an order of magnitude.

The company's products have obtained a number of national patent technologies, and the product launch has been recognized by the majority of customers, and have been widely used in middling coal Group, China Coal Group, Longmei Group, etc.

technical parameter

Compliant with the national standard testing method and the National Occupational Health Standard GBZ/T 192.4-2007 of the People's Republic of China

working principle

By using the principle of interferometer interference frequency modulation, the light emitted by the light source is converted into interference light through a Michelson interferometer, and then the interference light is irradiated onto the sample. The receiver receives the interference light with sample information, and the computer software performs Fourier transform to obtain the spectral image of the sample.

Product Features

1. Intelligent human-computer interaction design, allowing you to quickly and proficiently operate regardless of whether you have been exposed to it or not;

2. Unique data collection preview full monitoring mode, with a clear view of the collection process;

3. The whole machine is molded into an integrated mold, and the main components are aligned with the needle without adjustment. Users can replace the light source, detector, beam splitter, etc. by themselves, and it is convenient and flexible. Thoroughly solving the problem of difficult maintenance of traditional optical structures, users can install and easily replace optical components by themselves;

4. Equipped with an intelligent humidity automatic reminder device, it reduces the workload of operators in instrument maintenance. The electronic humidity digital intuitive display function will automatically remind users to replace desiccants, solving the biggest hidden danger in infrared use;

5. The instrument comes with a self checking program that can perform self checks on various indicators of the instrument at any time, and has real-time hardware online diagnosis;

6. More powerful software features: with self diagnostic function to ensure correct instrument status and testing parameters; Powerful data processing and analysis software, easy to handle operations such as peak calibration, peak area integration, baseline calibration, etc; Infrared software: Chinese version of 32-bit processing software. Including: infrared control, spectrum processing, data conversion, multi-component quantification and other operating software; H2O/CO2 automatic compensation software, self checking software; Macro program software;

7. Real time hardware online diagnosis: continuous online monitoring of all optical components (laser, light source, detector, beam splitter); Ensure that the instrument is always in excellent working condition and the measurement spectrum is accurate and reliable. Real time hardware online diagnosis: continuous online monitoring of all optical components (laser, light source, detector, beam splitter); Ensure that the instrument is always in excellent working condition, with software H2O/CO2 automatic compensation software that automatically removes water and carbon dioxide from the air;

8. The overall sealing and drying design of the optical platform improves the efficiency of light transmission and has excellent moisture resistance. Can adapt to various operating environments and reduce the impact of air absorption;

9. The instrument comes with analysis software and standard transmission accessories that can be assembled, such as sample preparation accessories for liquid tanks or KBr tablets. The sample warehouse can conveniently install ATR sample preparation accessories, accelerate sample preparation time, shorten cleaning time, and expand instrument functions;

10. Large sample compartment design, convenient for expanding various infrared accessories;

11. Equipped with a professional dust free silica automatic analysis system, it automatically issues experimental detection reports.

Instrument configuration

The free silica analyzer consists of a free silica analyzer host, silica analysis software, powder sample press, sample mold, grinder, KBr spectral purity, standard sample, etc;

Attachment:

GBZ

National Occupational Health Standards of the People's Republic of China

GBZ/T 192.4—2007

Dust in the air of the workplacedetermination

ThePart 4: Free silica content

Method for determination of dust in the air of workplace

Part 4: Content of free silica in dust

2007year06month18Daily Release 2007year12month30Daily implementation

Ministry of Health, PRC hair cloth

front word

GBZ/T 192according toIn the air of the workplaceThe characteristics of dust measurement are divided into the following five parts:

——The1Part: Total dust concentration

——The2Part: Concentration of respiratory dust

——The3Part: Dust dispersion

——The4Part: Free silica content

——The5Part: Concentration of asbestos fibers

This section isGBZ/T192The th4Part of it is inGB 5748-85Method for determination of dust in workplace air,GB16225-1996Appendix to the Health Standards for Respiratory Silicon Dust in Workshop AirBDust Free SilicaXLine Diffraction Measurement Method ",GB16245-1996Appendix to the Hygiene Standards for Respiratory Coal Dust in WorkplacesBThe method for determining free silica in respiratory coal dust by infrared spectroscopy isMade from basic revisions.

This section was proposed by the National Occupational Health Standards Committee.

This section is approved by the Ministry of Health of the People's Republic of China.

This sectionDrafting units: School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Industrial Hygiene Technology Research Institute of Wuhan Iron and Steel Company, Institute of Occupational Disease Prevention and Control of Dongfeng Motor Corporation, Wuhan Institute of Occupational Disease Prevention and Control, Hubei Provincial Center for Disease Control and Prevention, Fujian Provincial Center for Disease Control and Prevention, Liaoning Provincial Center for Disease Control and Prevention, Wuhan Analytical Instrument Factory.

This sectionMain drafters: Yang Lei, Chen WeihongLiu ZhanyuanChen Jingqiong, Li Jichao, Yi Guilin, Yang Jingbo, Mei Yong, Peng Kailiang, Liu Jiafa, Ye Bingjie.

5.1 principle

α-Quartz in infrared spectroscopy12.5μm（800cm^-1）The12.8μm（780cm^-1）And14.4（694cm^-1）μmA highly specific absorption band appears at this point, and within a certain range, its absorbance value isα-The quality of quartz is linearly related. Quantitative determination is carried out by measuring absorbance.

5.2 instrument

5.2.1Ceramic crucible and crucible clamp.

5.2.2Box type resistance furnace or low-temperature ashing furnace.

5.2.3Analytical balance with a sensitivity of0.01mg.

5.2.4Drying oven and dryer.

5.2.5Agate milk bowl.

5.2.6Tablet press and ingot mold.

5.2.7 200Dust sieve.

5.2.8Infrared spectrophotometer. withXAxis horizontal coordinate record900cm^-1~600cm^-1The spectrum, in900cm^-1Correct the zero point and100%, in order toYThe vertical axis represents absorbance.

5.3 reagent

5.3.1 Potassium bromide, high-grade purity or spectral purity, over200After sieving, grind by wet method, and then150After drying at ℃, store in a dryer for later use.

5.3.2Anhydrous ethanol, analytical grade.

5.3.3standardα-Quartz dust, with a purity of99%Above, granularity<5μm.

5.4 Sample collection

According to the measurement purpose, the sample collection method is described inGBZ 159andGBZ/T XXX.2orGBZ/T XXX.1The amount of dust collected on the filter membrane is greater than0.1mgAt this time, it can be directly used to determine the content of free silica in this method.

5.5 determination

5.5.1Sample processing: Accurately weigh the mass of dust on the filter membrane with dust collected（G）. Then fold the dust receiving surface inward in half3Next, place it in a porcelain crucible and place it in a low-temperature ashing furnace or resistance furnace (less than600After ashing at ℃, cool down and place in a dryer for later use. Weighing250mgAfter grinding and mixing the potassium bromide and ashed dust samples together in an agate mortar, they are placed in a drying oven along with the tablet mold（110℃±5℃)10minPlace the dried mixed sample in a compression mold and apply pressure25MPa, Continuously3minThe prepared ingot is used as the sample for measurement. At the same time, take a blank filter membrane and process it as a blank control sample.

5.5.2Drawing of Quartz Standard Curve: Accurately Weighing Standards of Different Massesα-Shi Yingchen（0.01mg ~1.00mg）Join separately250mgPotassium bromide is thoroughly ground evenly in an agate mortar, and transparent ingots are made according to the above sample preparation method. Place standard quartz ingots of different qualities in the optical path of the sample chamber for scanning800cm^-1、780cm^-1and694cm^-1The absorbance values at three locations are plotted on the y-axis, with quartz mass as the reference（mg）Draw three different wavelengths for the horizontal axisα-Quartz standard curve and calculate the regression equation of the standard curve. In the absence of interference, it is generally recommended to use800cm^-1Quantitative analysis of standard curves.

5.5.3Sample measurement: Scan and record the sample ingot and blank control sample ingot separately in the optical path of the sample chamber800cm^-1(or694cm^-1）Measure the absorbance value of the sample by repeated scanning3Next, after subtracting the average absorbance of the blank control sample from the average absorbance of the measured sampleα-The mass of free silica in the sample obtained from the quartz standard curve（m）.

5.5.4 calculation According to the formula（3）Calculate the content of free silica in dust:

（3）In the formula:SiO₂（F）——Free silica (α) in dust-The content of quartz,%；

m——The mass of free silica in the measured dust sample,mg；

G——Dust sample quality,mg.

5.6 matters needing attention

5.6.1The alpha of this law-The detected amount of quartz is0.01mgRelative standard deviation（RSD）For0.64%~1.41%The average recovery rate is96.0%~99.8%.

5.6.2 The particle size of dust has a certain impact on the measurement results, therefore, the sample and quartz dust used to make the standard curve should be thoroughly ground to make their particle size smaller than5μmOccupying95%Only then can analysis and determination be carried out.

5.6.3 The ashing temperature has a certain impact on the quantitative results of coal mine dust samples. If the coal dust sample contains a large amount of kaolin components, it will be higher than600Decomposition occurs during ashing at ℃800cm^-1Interference occurs nearby, such as when the ashing temperature is below600At ℃, this interference band can be eliminated.

5.6.4 If the dust contains components such as clay, mica, amphibole, feldspar, etc., it can be800cm^-1If there is interference nearby, it can be used694cm^-1Quantitative analysis of the standard curve.

5.6.5 To reduce random measurement errors, the laboratory temperature should be controlled within18℃~24℃, relative humidity less than50%It is appropriate.

5.6.6 The analysis conditions for preparing quartz standard curve samples should be completely consistent with the conditions of the tested sample to reduce errorsPoor.