GB/T 4634-1996 Determination of potassium, sodium, iron, calcium, magnesium and manganese in coal ash (atomic absorption spectrophotometry)
Some standard content:
GB/T4634---1996
This standard is a revision of GB4634--84 determination method for potassium, sodium, iron, calcium, magnesium and manganese in coal (original absorption spectrophotometry) based on GB/T1.1--93 standardization work guidelines. The main revisions are: 1. According to the relevant provisions of the promulgated "Legal Measurement Units", "Coal Quality Analysis Test Methods-General Provisions" and "Terms and Terms Related to Coal Quality and Coal Analysis", the non-standard terms, symbols, units, etc. in the original standard have been modified. 2. Based on many years of practical experience, some cumbersome links in the original standard test steps have been deleted and revised. 3. A volumetric flask has been added, and measures to prevent contamination of test glassware have been added. From the date of entry into force, this standard will replace GB4634--84. Appendix A of this standard is the appendix of the standard.
This standard is proposed by the Ministry of Coal Industry of the People's Republic of China. This standard is under the jurisdiction of the National Coal Standardization Technical Committee. This standard was drafted by: Beijing Coal Chemistry Research Institute of China Coal Research Institute, Laboratory of Zhejiang Coalfield Geological Exploration Company, Sichuan Coalfield Geological Research Institute.
The main drafter of this standard: Zhang Chuanzhi.
National Standard of the People's Republic of China
Determination of potassium, sodium, iron, calcium, magnesium and manganese in coal ash by atomic absorption spectrometric method1 Scope
GB/T4634—1996wwW.bzxz.Net
Replaces GB4634--84
This standard specifies the determination method of potassium, sodium, iron, calcium, magnesium and manganese in coal ash, and is applicable to the determination of potassium, sodium, iron, calcium, magnesium and manganese in dry lignite, bituminous coal and anthracite ash.
2 Principle
The sample is decomposed by perchloric acid-hydrofluoric acid. In the hydrochloric acid medium, release agent lanthanum or strontium is added to eliminate the interference of aluminum, titanium, etc. on calcium and magnesium, and the atomic absorption measurement is carried out with acetylene-air flame.
3 Instruments and equipment
3.1 Atomic absorption spectrophotometer.
3.2 Light source: hollow cathode lamp of potassium, sodium, iron, calcium, magnesium, and manganese elements. 3.3 Analytical balance: sensitivity 0.1mg.
3.4 Electric heating plate: adjustable temperature.
3.5 Polytetrafluoroethylene: 30mL.
3.6 Volumetric flask: 50ml.
Note: To prevent contamination, all glassware used in the test must be cleaned with 1+9 hydrochloric acid solution, especially the volumetric flask used for determining potassium and sodium must be cleaned with 3+97 hot hydrochloric acid solution and tested for sodium ion dissolution before use. 4 Reagents
Unless otherwise specified, all reagents used are of high-grade purity, and the water used is double distilled water or deionized water. 4.1 Hydrofluoric acid (GB 620).
4.2 Perchloric acid (GB623).
4.3 Hydrochloric acid (GB622).
4.4 Lanthanum solution (50mgLa/ml): Weigh 29.4g of high-purity (99.99%) lanthanum trioxide into a 400mL beaker, add 50mL of water, slowly add 100mL of (1+1) hydrochloric acid, heat to dissolve, cool and transfer to a 500mL volumetric flask, dilute to the mark with water, shake well, and transfer to a plastic bottle.
4.5 Strontium solution (50mgSr/ml.): Weigh 152g of strontium chloride (SrCl2·6H20) purified by recrystallization into a 400ml beaker, add water to dissolve, transfer to a 1000mL volumetric flask, add water to dilute to the scale, shake well, and transfer to a plastic bottle. Note: 1) Strontium chloride purification method: 1000g strontium chloride (SrCl2·6H20) is added with 400mL of water, heated to about 70℃ to dissolve, and 400mL of ethanol is added while hot, and after low overflow recrystallization, it is filtered and dried at 40-50℃. 4.6 Aluminum solution (1mgAl,0)/mL): Weigh 4.736g of aluminum chloride (AlCls6H0) in a 400mL beaker, add water to dissolve, transfer to a 1000g volumetric flask, add water to dilute to the scale, shake well, and transfer to a plastic bottle. 4.7 Potassium standard stock solution (1mgK0/ml): Weigh 1.5829g of high-purity potassium chloride (99.99%) burned at 500C for 30min in a 400mlL beaker, add water to dissolve, transfer to a 1000g volumetric flask, add water to dilute to the scale, shake well, and transfer to a plastic bottle. 4.8 Sodium standard stock solution (1mg Na2O3/ml): weigh 1.8859g of high-purity sodium chloride (99.99%) burned at 500C for 30min in a 400ml beaker, add water to dissolve, transfer to a 1.000mL volumetric flask, dilute to scale with water, shake well, and transfer to a plastic bottle. 4.9 Calcium standard stock solution (1mg CaO/mL): weigh 1.784g of high-purity calcium carbonate (99.99%) baked at 110 for 1h in a 400ml beaker, add 50ml of water, cover with a watch glass, slowly add 20mL of (1+1) hydrochloric acid along the wall of the beaker, heat and boil to drive out carbon dioxide after dissolution, rinse the watch glass and the wall of the beaker with water, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, shake well, and transfer to a plastic bottle. 4.10 Magnesium standard stock solution (1mgMgO/ml): Weigh 0.6030g of high-purity magnesium metal (99.99%) in a 400ml beaker, add 40ml of (1+1) hydrochloric acid solution, heat to dissolve completely, cool to room temperature, transfer to a 1000ml volumetric flask, dilute to scale with water, shake well, and transfer to a plastic bottle.
4.11 Iron standard stock solution (1mgFe2Os/mL): Weigh 1.000g of high-purity ferric oxide (99.99%) baked at 110℃ for 1h in a 400ml beaker, add 40ml of (1+1) hydrochloric acid solution, cover with a watch glass, slowly heat to dissolve, cool to room temperature, transfer to a 1000ml volumetric flask, dilute to scale with water, shake well, and transfer to a plastic bottle. 4.12 Manganese standard stock solution (1mgMnOz/ml): Weigh 1.000g of high-purity manganese dioxide into a 400mL beaker, add 40ml of (1+1) hydrochloric acid solution, cover with blood, slowly heat until completely dissolved, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, shake, and transfer to a plastic bottle.
4.13 Iron, calcium, and magnesium mixed standard working solution (Fe2O:, CaO200μg/mL, MgO50ug/mL): Accurately pipette 100mL of iron standard stock solution (4.11), 100mL of calcium standard stock solution (4.9), and 25mL of magnesium standard stock solution (4.10) into a 500mL volumetric flask, dilute to scale with water, shake, and transfer to a plastic bottle. 4.14 Potassium, sodium, and manganese mixed standard working solution (KzO, Na2O, MnO, 50μg/ml each): Accurately pipette 25mL each of potassium standard stock solution (4.7), sodium standard stock solution (4.8), and manganese standard stock solution (4.12) into a 500mL volumetric flask, dilute to scale with water, shake well, and transfer to a plastic bottle.
5 Test steps
5.1 Preparation of ash sample
The coal sample for analysis is burned into coal ash according to the ash-making conditions specified in the slow ash-making method (3.1) in GB212--91 "Industrial Analysis Methods of Coal". Then grind the coal ash with an agate mortar until it passes through a 160-mesh sieve, put it into a ground-mouth bottle, and store it in a desiccator. The ash sample should be burned at 815±10℃ for 30min before weighing.
5.2 Sample decomposition
Weigh 0.1±0.01g of the ash sample (5.1), accurate to 0.0002g, in polytetrafluoroethylene, moisten with water, add 2ml. perchloric acid, 10ml hydrofluoric acid, place on a hot plate and heat slowly (temperature not higher than 250℃), steam until white smoke is almost gone, remove the crucible, cool slightly, add (1+1) hydrochloric acid 10ml, water 10mL, place on the hot plate and heat until it is almost boiling and keep for 2min, remove the crucible, transfer the sample solution in the crucible into a 100mL volumetric flask with hot water, cool to room temperature, add water to dilute to the scale, and shake well. This solution is the original solution. Note: A reagent blank should be made for each batch of sample decomposition. Except for not adding ash sample to the reagent blank, the rest of the operation is the same as the sample decomposition. 5.3 Preparation of sample solutions to be tested
5.3.1 Sample solutions to be tested for iron, calcium, and magnesium: Accurately pipette 5 ml of the stock solution (5.2) into a 50 ml volumetric flask, add 2 ml of lanthanum solution (4.4) (when strontium is used as a release agent, add 2 ml of strontium solution instead) and 1 ml of (1+3) hydrochloric acid solution, dilute to the mark with water, and shake well. 5.3.2 Potassium, sodium, and manganese sample solutions: Accurately pipette 5 mL of the stock solution (5.2) into a 50 mL volumetric flask, add 1 mL of (1+3) hydrochloric acid solution, dilute to the mark with water, and shake well. 5.4 Preparation of mixed standard solutions series
5.4.1 Iron, calcium, and magnesium mixed standard solutions series: Pipette 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0 mL of the mixed standard working solutions (4.13) of iron, calcium, and magnesium respectively into a 100 mL volumetric flask, add 4 mL of lanthanum solution (when strontium is used as a release agent, add 4 mL of strontium solution and 3 mL of aluminum solution instead), and 4 mL of (1+3) hydrochloric acid solution, dilute to the mark with water, and shake well. The concentration of ferric oxide and calcium oxide in this standard series of solutions is 0-20ug/ml, and the concentration of magnesium oxide is 0-5μg/mL. 5.4.2 Potassium, sodium, and manganese mixed standard series of solutions: Pipette potassium, sodium, and manganese mixed standard working solutions (4.14) 0, 1.0, 2.0, 3.0, 4.0, 5.0.6.0.7.0.8.0, 9.0, and 10.0ml into a 100ml volumetric flask, add 4ml of (1+3) hydrochloric acid solution, dilute to the mark with water, and shake well. The concentration of potassium oxide, sodium oxide, and manganese dioxide in this standard series of solutions is 0-5ug/mL. Note: The concentration interval of the mixed standard series solutions in 5.4.1 and 5.4.2 may be increased or decreased depending on the instrument performance and the curvature of the working curve. 5.5 Determination of iron, calcium, magnesium, potassium, sodium and manganese 5.5.1 Determination of instrument working conditions: In addition to the analysis lines of each element specified in Table 1 and the flame gas used, adjust other instrument parameters: lamp current, passband width, burner height and angle, flow rate and pressure of fuel gas and auxiliary gas, etc. to the optimal values for the instrument used. Table 1
Analysis line, nm
Flame gas
Acetylene-air
Acetylene-air
Acetylene-air
Acetylene-air
Acetylene-air
Acetylene-air
5.5.2 Determination: According to the instrument working conditions determined in 5.5.1, measure the absorbance of the corresponding elements in the sample solution (5.3.1, 5.3.2) and the standard series solution (5.4.1, 5.4.2). Note: During the determination, use double distilled water to adjust the zero. The absorbance measured by the sample and the standard should be subtracted from the absorbance of the blank, and then used to draw the working curve and calculate the results.
5.5.3 Drawing of the working curve: With the concentration of the component measured in the standard series as the horizontal axis and the absorbance as the vertical axis, draw the working curve of each measured component on the coordinate paper.
6 Calculation of results
The concentration of the component (μg/mL) is found from the absorbance of the component in the sample solution on the working curve of the corresponding component, and its percentage content is calculated according to formula (1):
R.0.(%) = × 0. 001 × 100
Wherein: R..--K), Na2O.FeO3CaO, MgO, MnO2 and other components to be determined; · the concentration of the component to be determined found on the working curve, μg/mL; - sample mass, g.
7 Precision
Precision is as specified in Table 2:
GB/T 4634--- 1996
Content range
5～10
5～10
Repeatability
Reproducibility
GB/T4634-1996
Appendix A
(Standard Appendix)
Determination of iron, calcium and magnesium in fly ash of alkali fusion sample system Except for the following provisions, the other provisions are the same as the main text of this standard. A1 Preparation of sample solutions of iron, calcium and magnesium to be tested: Accurately pipette 5ml of sample solution A (6.1.2) in the coal ash component analysis method of GB/T1574. In a 50ml volumetric flask, add 4ml of lanthanum solution (when strontium is used as a release agent, add 4ml of strontium solution instead) and dilute to the scale with water. A2 Iron, calcium, magnesium mixed standard series solution: Pipette iron, calcium, magnesium mixed standard working solution (4.13) 0, 1.0, 2.0, 3.0, 4.05.0.6.0.7.0, 8.0, 9.0.10.0ml respectively into a 100ml volumetric flask, add 5ml of sample blank solution, 4ml of lanthanum solution (when using strontium as a release agent, add 4ml of strontium solution and 3ml of aluminum solution instead), dilute to the scale with water, and shake well. The concentration of iron trioxide and calcium oxide in this series of standard solutions is 0-20μg/ml, and the concentration of magnesium oxide is 0~~5μg/mL. A3 Result Calculation
The absorbance of the measured component in the sample solution is obtained. The concentration of the component is found on the working curve of the corresponding component, and its percentage content is calculated according to formula (A1):
RO.(%)= c×0. 002 5
Formula: RO.-Fe2O, CaO, MgO and other measured components; 100.
CThe concentration of each measured element found on the working curve, ug/mL; m.Sample mass..
(A1)g.
7 Precision
Precision is as specified in Table 2:
GB/T 4634--- 1996
Content range
5～10
5～10
Repeatability
Reproducibility
GB/T4634-1996
Appendix A
(Standard Appendix)
Determination of iron, calcium and magnesium in fly ash of alkali fusion system Except for the following provisions, the other provisions are the same as the main text of this standard. A1 Preparation of iron, calcium and magnesium sample solutions to be tested: Accurately pipette 5 ml of sample solution A (6.1.2) in the coal ash component analysis method of GB/T1574. In a 50 ml volumetric flask, add 4 ml of lanthanum solution (when strontium is used as a release agent, add 4 ml of strontium solution instead) and dilute to the scale with water. A2 Iron, calcium, magnesium mixed standard series solution: Pipette iron, calcium, magnesium mixed standard working solution (4.13) 0, 1.0, 2.0, 3.0, 4.05.0.6.0.7.0, 8.0, 9.0.10.0ml respectively into a 100ml volumetric flask, add 5ml of sample blank solution, 4ml of lanthanum solution (when using strontium as a release agent, add 4ml of strontium solution and 3ml of aluminum solution instead), dilute to the scale with water, and shake well. The concentration of iron trioxide and calcium oxide in this series of standard solutions is 0-20μg/ml, and the concentration of magnesium oxide is 0~~5μg/mL. A3 Result Calculation
The absorbance of the measured component in the sample solution is obtained. The concentration of the component is found on the working curve of the corresponding component, and its percentage content is calculated according to formula (A1):
RO.(%)= c×0. 002 5
Formula: RO.-Fe2O, CaO, MgO and other measured components; 100.
CThe concentration of each measured element found on the working curve, ug/mL; m.Sample mass..
(A1)g.
7 Precision
Precision is as specified in Table 2:
GB/T 4634--- 1996
Content range
5～10
5～10
Repeatability
Reproducibility
GB/T4634-1996
Appendix A
(Standard Appendix)
Determination of iron, calcium and magnesium in fly ash of alkali fusion system Except for the following provisions, the other provisions are the same as the main text of this standard. A1 Preparation of iron, calcium and magnesium sample solutions to be tested: Accurately pipette 5 ml of sample solution A (6.1.2) in the coal ash component analysis method of GB/T1574. In a 50 ml volumetric flask, add 4 ml of lanthanum solution (when strontium is used as a release agent, add 4 ml of strontium solution instead) and dilute to the scale with water. A2 Iron, calcium, magnesium mixed standard series solution: Pipette iron, calcium, magnesium mixed standard working solution (4.13) 0, 1.0, 2.0, 3.0, 4.05.0.6.0.7.0, 8.0, 9.0.10.0ml respectively into a 100ml volumetric flask, add 5ml of sample blank solution, 4ml of lanthanum solution (when using strontium as a release agent, add 4ml of strontium solution and 3ml of aluminum solution instead), dilute to the scale with water, and shake well. The concentration of iron trioxide and calcium oxide in this series of standard solutions is 0-20μg/ml, and the concentration of magnesium oxide is 0~~5μg/mL. A3 Result Calculation
The absorbance of the measured component in the sample solution is obtained. The concentration of the component is found on the working curve of the corresponding component, and its percentage content is calculated according to formula (A1):
RO.(%)= c×0. 002 5
Formula: RO.-Fe2O, CaO, MgO and other measured components; 100.
CThe concentration of each measured element found on the working curve, ug/mL; m.Sample mass..
(A1)
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