HG 2958.7-1988 Determination of iron content in celestite ore Sulfosalicylic acid spectrophotometric method HG2958.7-1988 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of iron content in celestite ore
Sulfosalicylic acid spectrophotmetric method
Ceiestlte ores- Determination of iron contentSulphosalicylic acid spectrophotmetric method Subject content and scope of application
This standard specifies the determination of iron content in celestite ore by sulfosalicylic acid spectrophotometric method. This standard is applicable to celestite ore products with iron oxide content of 0.1% to 12%. 2 Method Summary
UDC 549. 761. 3
GB 9018. 7
Pr8.7-tPe
The sample is acidified after sodium hydroxide-sodium peroxide molten water leaching. In sodium acetate-hydrochloric acid buffer solution (pH 5.3), trivalent iron and sulfosalicylic acid form a yellow-brown complex. At a wavelength of 450nm, ferric oxide complies with Beer's law in the range of 0 to 1000ug/100mL.
3 Reagents and solutions
3.1 Sodium hydroxide (GB629-81);
3.2 Sodium peroxide;
3.3 Hydrochloric acid (GB62277)
3.4 ​​Hydrochloric acid: 1+1 solution;
Hydrochloric acid: 1+1 Solution:
Ammonia (GB63177): 1-1 solution,
Sulfosalicylic acid (HG3-991--81): 20% solution (filtered and stored in a brown bottle); Lactic acid: 1-4 solution;www.bzxz.net
Sodium acetate (CH,COONa·31I,O) (GR 693-77); Buffer solution: Dissolve 500g sodium acetate (3.9) in 500mL hot hydrochloric acid (3.5), filter, cool, and dilute with water to 1000ml. Add 3.10
ferric oxide (high purity reagent);
ferric oxide standard solution: 100mg/L. Weigh 1.0000? of ferric oxide 3.12
(3.11) pre-calcined at 750~~800C for 1h in a 200mL beaker, add 30mL hydrochloric acid (3.4), and heat at low temperature until dissolved. Finally, cool to room temperature, transfer to a 100DmL ​​volumetric flask, dilute with water to the mark, and shake well. Pipette 50.00mL of the above solution into a 500mL volumetric flask, dilute with water to the mark, and shake well. This solution contains 100μg of ferric oxide per milliliter.
4 Instrument
Spectrophotometer.
Approved by the Ministry of Chemical Industry of the People's Republic of China on March 21, 198818
Implemented on December 1, 1988
5 Sample
GB 9018.788
The sample shall pass through a 0.075mm sieve (GB6003-85), be dried at 105~110℃ to constant weight, and be placed in a desiccator to cool to room temperature. 6 Analysis steps
6.1 Take 0.1~0.3g of sample (weighed to 0.0002g) and add 3g of sodium hydroxide (3.1) and a little sodium peroxide (3.2) to a jar. Cover with a lid (leave a gap), place in a furnace, raise the temperature to 300°C, wait for 10min, continue to raise the temperature to 700°C, keep for 30min, take out and cool, place in a 250m. beaker, add 3040mL of hot water, heat to remove the molten material, use a few drops of hydrochloric acid (3.5), wash with hot water, add 10mL of hydrochloric acid (3,3), cover the surface, heat and boil for several minutes, remove, cool to room temperature, transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. 6.2 Dry filtration. Take 5.00-25.00ml of the filtrate in a 100mL volumetric flask and dilute to 50ml with water. 6.31mL lactic acid (3.8), 1mL salicylic acid solution (3.7), add nitrogen water (3.6) dropwise, the solution changes from purple red to yellow. Add 10ml buffer (3.10), dilute with water to the mark, shake well. After 10 minutes, use a 1m absorption cell (if the iron oxide content in the test cell is less than 1.00%, use a 2cm absorption cell), at 450° on the spectrophotometer, use the empty test solution as the reference drop, and measure its absorbance. Perform a blank test at this time.
7 Drawing of standard curve
Use a micro-burette to take 0.00, 1.00, 2.0), 4.10, 6.00, 8.00, 10.00mL of ferric oxide standard solution (3.12) and put them into a group of 100mL bottles respectively, dilute to mL with water, and proceed as per analysis step 6.3, taking the reagent blank as the reference solution and measuring the absorbance.
Draw the standard curve with the micrograms of ferric oxide contained in 100mL of the standard colorimetric solution as the coordinate and the corresponding absorbance as the ordinate.
Calculation of analysis results
The percentage content (X) of ferric oxide (FeO2) is calculated as follows: x=mx 10
-× 100
Wherein: m, - the amount of ferric oxide found on the standard curve, limit; - the volume of the test solution taken, ml;
the mass of the sample,.
9Tolerance
The difference between the results of the determination in the same experimental space should be less than the value shown in the following table. %
FeO3O3 (Fe,O2)
0.1-~ 1.00
2> 1.00-~ 5.00
2 3.00 ~- 12.00
Additional remarks:
GE 9018.7—88
This standard is under the jurisdiction of the Chemical Industry Design and Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Chemical Industry Design and Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Min Yuyao and An Lihua. 20
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