This standard is applicable to the determination of particle size distribution of yttrium oxide and europium oxide by light transmission method. GB/T 8761-1988 Determination of particle size distribution of yttrium oxide and europium oxide by light transmission sedimentation method GB/T8761-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of particle size distribution of yttrium oxide andeuropium oxide by sedimentation and light obscuration method This standard applies to the determination of particle size distribution of yttrium oxide andeuropium oxide by sedimentation and light obscuration method. 1 Principle
At the beginning of sedimentation (t=0), the powder suspension is in a uniform state, and its mass concentration is C0UDC 661.866+661
.866.1:620.186
GB 8761.-88
At a depth below the liquid surface, a beam of parallel light is passed through the suspension (see Figure 1). In the early stage of particle sedimentation, particles of various sizes at the beam plane are replaced by particles reaching the beam plane from above, so the concentration at the beam plane remains unchanged. When the largest particle in the suspension crosses the beam plane from the liquid surface, no larger particle reaches the beam plane anymore, so the concentration at this point begins to decrease. Figure 1 Schematic diagram of the method principle
1—light source; 2—suspension
At the moment (starting from the moment of uniformity of the suspension), the suspension at the plane of the light beam (depth) contains only those particles whose diameter is smaller than that determined by the Stokes formula, see formula (1): 18n·h
(pe-μ)gt
Formula I: n2-liquid viscosity, N·s/m,
h sedimentation height, m;
-effective density of solid powder, kg/m2; density of liquid medium, kg/m2;
gravitational acceleration (take 9.81), m/s;
sedimentation time, S.
When light passes through the suspension, in addition to the absorption of light by the liquid itself, the powder particles in the suspension also scatter and absorb light, resulting in attenuation of light intensity. The attenuation of light intensity satisfies the Beer-Lambert law. China Nonferrous Metals Industry Corporation approved 388 on February 4, 1988.
implemented on February 1, 1989
wherein: le1
GB 8761-88
Ig(I./) = kmca·1www.bzxz.net
is the intensity of the incident light with the same intensity after passing through the liquid medium and the intensity of the light passing through the suspension at time;
extinction coefficient;
C. ——mass concentration of the suspension + g/L. L is the thickness of the suspension layer, cm.;
If after a time interval of (1/j = i+1), the intensity of the light passing through the suspension changes from, to (1,), since at time t and t, all particles with a particle size greater than d. and d, (d:) have settled to the beam plane, the particle mass is given by formula (3): Amy oc dn(Igt, -- Igl.)
dm = (d, +d,)/2
Where: Ami--
The mass of particles with a particle size between d, and d. in the sample; the average value of particle sizes d, and d,.
Calculate d(1gl,igli) for each selected particle size interval, and then calculate the sum for all particle size intervals. Then the mass percentage of particles with a particle size of. to in the sample is given by formula (5): mj (%)
2Reagents
2.1Sodium hexametaphosphate solution, 0.2%.
dm(Igt, - Igt)
Sd.(igl. - Igt,)
2.2 Sub-boiling distilled water, ion exchange water is distilled through quartz sub-boiling. 2.3 Glycerol anhydrous ethanol solution, 20%.
3 Instruments
Micron light transmission particle size distribution analyzer, measuring range 0.1~50μm. 3.1
3.2 Ultrasonic cleaner, power 20~45W, frequency 35~40Hz. 3.3 Gun-type stirrer.
Thermometer, 0~50℃ (accurate to 0.1). Sample preparation and requirements
4.1 Sampling quantity: Take two samples for measurement and take the average value. X100
4.2 Sampling method: After fully mixing the oxidized billion or oxidized silver sample, take the front, back, left and right four points with a radius of about 1.0 and a radius of about 0.01. In a 150mL beaker, add 100mL sodium hexametaphosphate solution (2.1) (for europium oxidation) or glycerol anhydrous ethanol solution (2.3) (for europium oxidation).
4.3 Ultrasonic dispersion; put the beaker into an ultrasonic cleaner (3.2) at a power of 45W for 3 minutes of ultrasonic dispersion, remove it and place it at room temperature for testing.
5 Measurement steps
Measurement steps take SKC-2000 as an example.
5.1 Turn on the power to put the instrument in normal working condition. 5.2 Input test conditions:
5.2.1 Use a thermometer (3.4) to measure the temperature of the ultrasonically dispersed sample (4.3) system. According to this temperature, find out the density and viscosity values ​​of the sodium hexametaphosphate solution (2.1) or glycerol anhydrous ethanol solution (2.3) at this temperature in the table and input them into the microprocessor. 385
GB 8761-88
5.2.2 Input the particle size interval: for powders below 5μm, take 1μm; for powders below 10μm, take 2μm; for powders below 30μm, take 5μm; for powders below 50um, take 10μm.
5.3 Put the sedimentation tank containing the sodium hexametaphosphate solution (2.1) or glycerol anhydrous ethanol solution (2.3) into the instrument in a vertical and balanced manner and measure its light transmittance 1 (at this time 1.100).
5.4 Preparation of suspension: Transfer the ultrasonically dispersed sample (4.3) to the sedimentation tank under strong stirring, repeatedly invert the tank by instant inversion method, mix more than ten times, and adjust the initial concentration so that the measured light transmittance 1g (1./1) is between 1.3 and 1.1. 5.5 Immediately put the sedimentation tank containing the uniformly mixed suspension (5.4) into the instrument, and measure the natural sedimentation and centrifugal sedimentation according to the instrument operating procedures.
5.6 Print the experimental report.
6 Representation of results
For each particle size interval &, the mass percentage to is processed and converted into the cumulative mass percentage of each particle size, and the table is presented. It can also be presented in a chart: the particle size is the horizontal axis, the cumulative mass percentage of particles smaller than the particle size is the vertical axis, and the particle size at 50% is the central particle size (ts.). The representation method takes yttrium oxide as an example, as shown in Table (1) and Figure (2). 6.1 Expressed in tabular form
Sample name: Yttrium oxide.
Medium liquid: 0.2% sodium hexametaphosphate solution. Table 1
Between particle sizes,
Cumulative mass,
6.2 Expressed in particle size distribution curve
de. =3. 84
7Tolerance
Result expression method
The relative deviation of the center particle size analysis results between laboratories should be less than 10%. 390
Test report
The test report shall include the following contents:
This standard number,
Details of the sample required,
The instrument used;
Sample processing method (dispersion conditions);
GB876188
Viscosity value and density value of the medium, name and amount of dispersant; test results;
Any details that may affect the test results.
Additional remarks:
This standard was drafted by Beijing General Research Institute of Nonferrous Metals and Shanghai Yuelong Chemical Plant. This standard was drafted by Shanghai Yuelong Chemical Plant.
The main drafters of this standard are Chen Manli and Zhang Shenxiong. 391
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