The first group standard in the field of titanium dioxide-determination of specific oxides in titanium dioxide X-ray fluorescence spectrometry

Shandong Dongjia led the development of CSTM (China Materials and Test group standards) standard "Titanium white powder in the determination of specific oxides X-ray fluorescence spectroscopy", the National Chemical Industry Productivity Promotion Center titanium white sub-center organization coordination "Pansteel Group Titanium Resources Co., Ltd.", "Shandong Daun Titanium Co., Ltd." and other units to participate in the standard, after a year of joint efforts, has now entered the standard approval stage.
1 Range
This standard specifies test principles, reagents or materials, instruments, samples, test steps, test data processing, precision and test reports for determining the content of titanium dioxide (TiO2), silicon dioxide (SiO2), aluminum trioxide (Al2O3) and iron trioxide (Fe2O3) using X-ray fluorescence spectroscopy.
standard is applicable to the determination of the above four specific oxides with content of more than 0.005% in titanium white powder
the
. The determination of other types of oxides may also be referred to this standard.
2 normative reference file
the following files are essential for the application of this file. Where a reference file is dated, the date-only version applies to this document. Any reference file that does not note a date, the latest version (including all modification orders) applies to this document.
GB/T 3186 color paint, varnish and varnish with varnish raw materials sampling
GB/T 6682-2008 Analysis laboratory water specifications and test methods
GB/T 8170 numerical repair rules and limit values of the
3 principle
samples by melting or pressure sheet legal into a sample, using X-ray fluorescence spectroscopy to determine the X-ray fluorescence spectral strength of the characteristics of the elements to be tested. Standard samples are tested with a melt sample and the background is measured at the baseline near the characteristic spectral line as a sample background deduction. The basic α between elements is corrected by theoretical coefficient, and the spectral line interference correction is carried out at the same time, and the spectral line strength and concentration after correction are used as calibration curves. The oxide content is calculated according to the quantitative relationship between the X-ray fluorescence spectral strength of the element to be measured and the corresponding oxide content of the element to be measured.
4 Reagents or Materials
Unless otherwise specified, only reagents identified as analyzing purity and above and distilled or deionized water that meet the requirements of GB/T 6682-2008 level III water are used in the analysis.
4.1
Calibration oxides: titanium dioxide, content greater than or equal to 99.99% (mass fraction); If you calibrate the value of the oxide without burning loss, the amount of burn loss is determined.
4.2
: waterless lithium tyborate, excellent pure, 700 degrees C burning at least 2h, cooled in the dryer to room temperature standby.
: Waterless lithium tyborate is used as a melt when the sample is used in the legal sample of the melt. Other suitable melts, such as waterless lithium boric acid, can also be used.
4.3
release agent: lithium bromide saturated water solution.
: Lithium bromide saturated aqueous solution is used as a release agent when preparing samples for the legal system of the melt. Other suitable release agents, such as ammonium bromide release agents, can also be used.
4.4
adhesive: boric acid.
: Boric acid is used as a binder when pressing legal samples. Other suitable binders, such as cellulose, are also available.
5 Instruments
5.1
wavelength dispersion X-ray fluorescence spectroscopy analyzer: end window target X-ray tube, power is not less than 3kW.
5.2
: Actual score value d s 0.1mg.
5.3
platinum-gold palladium (95 per cent Pt plus 5 per cent Au).
: When the fuses are melted and molded directly in the platinum-gold crucible, the inner wall of the platinum-gold crucible bottom should be smooth and smooth.
5.4
-gold mold (95% Pt-5%Au): about 1 mm thick and not easily deformed. The mold is regularly polished with a gold cast with a grain size of 14 m, making the glass sheet easy to peel off from the mold without breaking.
: Platinum-gold molds and platinum-gold crucibles can be combined.
5.5
: Automatic flame melter or high frequency inductive melter. If other types of fuses are used, the temperature is not less than 1100 degrees C and the temperature is controllable.
5.6
powder pressure sampler: the maximum pressure is not less than 15MPa, you can choose to set the production pressure.
5.7
: maximum temperature is not less than 1100 degrees C.
5.8
drying box: can maintain the temperature (105±2) degrees C.
5.9
dryer: contains a suitable desiccant.
5.10
: 30mL.
5.11
steel metal sieve: aperture 75 m.
6 samples
be sampled according to GB/T 3186 or by agreed methods. The amount of sampling is determined according to the testing needs.
the sample is finely ground, all stainless steel metal sieves with an aperture of 75 m (see 5.11), placed in a drying box (see 5.8) and pre-dried 2h to 4h at (105±2) degrees C and stored in a dryer (see 5.9).
7 Test Step
7.1 Parallel Test
two trials in parallel.
7.2 sample preparation
7.2.1 melting method
7.2.1.1 burn loss measurement
with clean porcelain crucible (see 5.10), burned at 1050 degrees C to constant weight, cooling standby. A dry sample of about 2g (accurate to 0.1 mg) is described, placed in a constant-weight porcelain crucible (see 5.10), then placed in a Maffer furnace (see 5.7), burned to constant at 1050 degrees C, cooled to room temperature, placed in a dryer (see 5.9), and burned for test samples. Sample burn-loss (LOI) is expressed as a mass score (%) and is calculated in formula (1):

m0 - dry sample quality in grams
(g);
calibration oxides such as titanium dioxide, silica, aluminum trioxide and iron trioxide (see 4.1) have a burn loss value and do not require this procedure.
7.2.1.2 Preparation of standard samples
calibration oxides such as titanium dioxide, silica, aluminum trioxide and iron trioxide (see 4.1) to prepare standard samples in an appropriate proportion. When drawing standard curves using standard samples, each chemical composition should have sufficient content range and a certain gradient.
In platinum-gold palladium (see 5.3), the standard sample, waterless lithium tyborbonate (see 4.2), accurate to 0.1 mg, sample melt ratio of 1:20, mixed evenly after adding 2 to 3 drops of lithium bromide de-molding agent (see 4.3), put into the melting machine (see 5.5), heat up to 1050 degrees C, until fully melted, then poured into the platinum-gold mold (see 5.4) and cooled to room temperature to make a glass melt with smooth surface, no obvious cracks and other defects, stored in the dryer (see 5.9) to prevent moisture absorption and contamination. When measuring, only the edges of the sample can be taken to avoid contamination of the X-ray measuring surface.
: The sample melt ratio can also be adjusted according to the actual situation.
such as titanium dioxide, silica, aluminum trioxide, iron trioxide and other calibration oxides (see 4.1) have a burn loss value, the actual sample amount can be obtained by conversion.
the preparation of the test sample
test sample is consistent with the preparation of the standard sample (see 7.2.1.2).
7.2.2 Pressure Plate Method
7.2.2.1 Preparation of standard samples
calibration oxides such as titanium dioxide, silica, aluminum trioxide, iron trioxide (see 4.1) are used to prepare standard samples in an appropriate proportion. When drawing standard curves using standard samples, each chemical composition should have sufficient content range and a certain gradient.
the standard samples using the melting method (see 7.2.1.2).
can also be used to prepare standard samples of the pressure chip legal system. It is said that the standard sample of about 4g preparation is put in the mold, with boric acid powder (see 4.4) trim mat bottom, pressurized to 10MPa in the powder sampler (see 5.6), maintain 5s, reduce pressure to remove, put in the dryer (see 5.9) to save, to prevent moisture absorption and pollution. The standard samples made should have smooth surfaces and no obvious cracks and other defects. When measuring, only the edges of the sample can be taken to avoid contamination of the X-ray measuring surface.
: The production pressure and hold time can also be adjusted according to the actual situation.
7.2.2.2 Preparation of test samples
The preparation steps for test samples are consistent with the method of preparing standard samples for press-chip legal systems (see 7.2.2.1).
7.3 X-ray fluorescence spectroscopy
7.3.1 measurement conditions
set the appropriate X-ray tube voltage, current, input the measurement parameters of each analysis element and the content of the oxides in the standard sample. Since the test parameters depend on the instrument used, the general parameters of X-ray fluorescence spectral analysis cannot be given, and the parameters listed in Appendix A have been shown to be appropriate for the test.
7.3.2 Background Correction
the background is measured at the baseline near the feature line as a sample background deduction. The peak X-ray intensity of the feature line is calculated as the net strength of the analytical line after deducting the background X-ray intensity.
7.3.3 calibration curve
the spectral strength of each of the measured elements in the standard sample series. The measured X-ray intensity is corrected by the background (see 7.3.2) to establish a calibration curve between the corresponding content of each specific oxide. The basic α between elements is corrected by theoretically correcting the coefficient.
the calibration curve established by the melt, which is used for the content test of the tablet sample, the dilution of the sample by the melt is taken into account and the conversion is required.
: If there are elements of spectral overlap interference, spectral overlap interference correction is also required when measuring the content of other types of oxides by reference to this standard.
of the calibration curve at 7.3.3.1
is determined using another standard sample that is not involved in the calibration curve. The relative deviation between the measured value and the theoretical value of each specific oxide content should be less than the corresponding repetition limit, confirm that the calibration curve is valid, otherwise it is not valid and should be re-made.
7.3.3.2 Drift Correction
Select a suitable sample with known specific oxide content, with good uniformity and stability, prepare samples with melting chip legal system, as drift correction samples to correct the instrument regularly, can be corrected by single or two points, correction time interval, according to the stability of the instrument and the analysis of the environment.
7.3.4 sample test
the sample to be tested under the same test conditions as the test standard sample, the X-ray intensity of the test sample should be within the range of the calibration curve. Based on the calibration curve (see 7.3.3), calculate the content of the element oxide i in the test sample Ci.
8 Test Data Processing
8.1
Melting
The content of the element oxide i to be tested in the sample is measured in mass fraction omega i, expressed in % and calculated according to the following formula:
:
Ci - the content of the element oxide i in the test sample, expressed in
%;
8.2
press sheet method
the content of the element oxide i to be tested in the sample is measured in mass fraction omega pressure i, expressed in %, according to the following formula:
:
Ci - the test sample of the element to be tested oxide i content, expressed in %.
8.3
data
the average of the results of the two parallel tests and the results are reported on an average basis. When the measured value is greater than or equal to 0.10%, it is reserved until two places after the dot, and when the measured value is greater than or equal to 0.005% and less than 0.10%, it is reserved for three places after the dot. All result data are repaired in accordance with GB/T 8170.
9 Precision
9.1 Repetition Limit (r)
the measurement of two independent test results under repetitive conditions, in the average range given below, the relative deviation of the two test results does not exceed the relative deviation listed in the table below, and the relative deviation does not exceed 5%.
9.2 Reproducible Limit (R)
obtains the measured value of two independent test results under reproducible conditions, and within the average given below, the relative deviation of the two test results does not exceed the relative deviation listed in the table below, and the relative deviation does not exceed 5%.
10 Test Report
The test report should include at least the following:
a) this standard number;
b) identify all the details necessary for the product to be tested;
c) the method used to prepare the sample for the calibration curve and the test sample
(melting, or pressing);
d) any differences from the prescribed test method;
e) the test date.
A
(Data Appendix)
X-ray fluorescence spectroscopy assay conditions
X-ray fluorescence spectroscopy assay conditions are available in Table A.1.
if you intend to participate in the development of this standard, please contact the Titanium Powder Center of the National Chemical Industry Productivity Promotion Center by December 18, 2018 at 0519