HG 2958.8-1988 Determination of aluminum content in celestite ore Chrome azure S spectrophotometric method
Some standard content:
National Standard of the People's Republic of China
Determination of aluminium content in celestite ores
Chromazuril Sspectrophotometric method
Cclestite ores Dietermination of aluminium content-
Chromazuril Sspectrophotometric method Subject content and scope of application
This standard specifies the determination of aluminium content in celestite ores by the chromazuril Sspectrophotometric method. This standard is applicable to celestite ores with a lead oxide content of 0.1% to 1%. 2 Method summary
UDC 549. 761. 3
GB 9018. 8-.- 88
2158.8-188
The sample is melted with sodium hydroxide, extracted with hydrochloric acid, and aluminum is coprecipitated with hexamethylenetetramine using iron as a carrier to separate it from strontium, lead, etc. The precipitate is dissolved with hydrochloric acid. In the presence of polyvinyl alcohol in acetate buffer solution, aluminum and chrome blue S form a purple-red complex, and its absorbance is measured at 620nm in a spectrophotometer. 3 Reagents and solutions
Sodium hydroxide (GB629-81)
3.2 Sodium peroxide:
Hydrochloric acid (GB62277) 1+1 solution:
Hydrochloric acid: 1+2 solution;
Hydrochloric acid: 1+99 Solvent;
Nitric acid (GB626-78): 1+1 solution; 3.6
Ammonium acetate (GB129277);
Sodium acetate (CH,COONa-3H1,O) (GB693-77) Potassium hydroxide (GB2306-80): 5% solution (lead-free), stored in a plastic bottle: Ascorbic acid: 2.5% solution (prepared when used) Methanol (GB68379);
Anhydrous ethanol (GB678-78);
Hexamethylenetetramine (GB1400-78): 25% solution; 3.13
Nitrogen chloride ammonium (GB658-77); 2% solution; 3.14
Methyl orange (HGB30 89-59: 0.1% solution; ammonia water (GB631-77): 1+1 solution;
polyvinyl alcohol: 4% solution. Dissolve 4g polyvinyl alcohol in 10m, methanol (3.11) add 70mL water, heat to boiling, filter, cool. Dilute with water to 100ml.,
3.18 chrome azure S: .1% solution, dissolve 1g chrome azure S in 6mL nitric acid (3.6), add 500mL anhydrous ethanol (3.12), 200mL water, mix, transfer this solution into a 1000mL volumetric flask, dilute with water to the scale, shake well. Approved by the Ministry of Chemical Industry of the People's Republic of China on March 21, 1988, implemented on December 1, 1988
GB 9018. 8—88
This solution can be used for 14 days;
3.19 Z. Acid buffer solution: dissolve 271g ammonium acetate (3.7) in 100mL water, dissolve 109g sodium acetate (3.8) in 250ml. water, combine the two solutions, filter, dilute with water to 1000mL, shake; 3.20 Alumina standard solution: 10.0m/L. Weigh 0.1058g of metal lead (99.90%) with surface oxide removed and place it in a beaker, add 25mL hydrochloric acid (3.3), heat to dissolve, evaporate the solution to wet salt, add 5mL hydrochloric acid (3.3), rinse the beaker with water, add 1 hot melt wave until the salts are dissolved, cool, transfer to a 1000mL container, dilute with water to the scale, and shake. Aspirate 25.00mL 1: Put the standard solution in a 500mL volumetric flask, add 5mL hydrochloric acid (3.3), dilute to the mark with water, and shake well. This solution contains 1 cobalt oxide per liter.
3.21 High iron solution: weigh 1.0g ferric oxide (excluding aluminum) in a 250mL beaker, add 25ml. lack of acid (3.3).: heat bath solution, cool, transfer to a 1000mL volumetric flask, dilute to the mark with water: 4 Instrument
Spectrophotometer.
5 Sample
The sample passes through a 0.075mm sieve (GB6003-85). Dry at 105~110r! to constant weight, and place in a ten-blast towel to cool to room temperature. 6 Analysis steps www.bzxz.net
6.1 Weigh 0.20.38g of sample (accurate weighing 0.0002g) in a crucible, add 1g of sodium hydroxide (3.1) and a little sodium peroxide (3.2), cover the crucible (leave a gap), place the crucible in a muffle furnace, raise the temperature to 300℃, stay for 10min, continue to raise the temperature to 700℃, keep for 3min, take out and cool. Put the crucible in a 250mL beaker, add 10mL of water and 25mL of hydrochloric acid (3.3), heat at low temperature, take out the molten material, rinse it with water, add 5mL of high iron solution (3.21), cover the surface, and heat to boiling. 6.2 Dilute with water to 100mL, add 1~2 drops of neutral orange indicator (3.15), add 5ml. hexamethylenetetramine solution (3.13), add water (3.16) to neutralize until the solution turns yellow, then add hydrochloric acid (3.3) until the solution turns red and 3~4 drops in excess. Add 20ml hexamethylenetetramine solution (3.13) under stirring. Heat and boil for 1~2min. After the precipitate settles, filter it with medium-speed filter paper while it is hot. Wash the beaker and precipitate twice with hot ammonium chloride washing solution (3.11): 6.3 Use 8ml. hot hydrochloric acid (3.4) to dissolve the filter paper and the residual precipitate in the beaker in a 100mL volumetric flask, wash the filter paper several times and the beaker 3~4 times with hot hydrochloric acid washing solution (.5), cool to room temperature, dilute with water to 100mL, shake the spoon, and leave to clarify. Pipette 5.00 mL of clear liquid into a 100 mL volumetric flask and dilute to 50 mL with water.6.4 Add 1 drop of base orange indicator solution (3.15) and carefully add potassium hydroxide solution (3.9) while shaking continuously until the solution just turns yellow. Add 6 drops of hydrochloric acid (3.3) (drop directly into the solution, do not let it flow down the wall). Shake the spoon. Add 2 mL of ascorbic acid solution (3.10), shake well, and let stand for 5 minutes. Add 10 mL of chrome blue solution (3.18), 5 mL of polyvinyl alcohol solution (3.17), and 20 mL of acetate buffer solution (3.19) along the neck of the volumetric flask in a circle, and dilute to the scale with water. Shake the hook. After 30 minutes, select a 2 cm absorption cell and measure its absorbance at 620 nm in a spectrophotometer with the empty test solution as the reference solution.
Perform a blank test at the same time.
7 Drawing of standard curve
Use micro-burette to measure 0.00, 1.00, 2.00, 4.006.00, 8.00, 10.00mL of aluminum oxide standard solution (3.20) respectively in a 100mL container, add 5ml of blank test solution, and dilute to 50nL with water. The following analysis is carried out according to step 6.4, and the absorbance of the blank solution is measured with the reagent as the reference solution.
The standard curve is drawn with the micrograms of aluminum xenon contained in 100mL of standard colorimetric solution as the horizontal axis and the corresponding absorbance as the vertical axis.
Calculation of analysis results
The content (X) of aluminum oxide (A,O) is calculated as follows: x = m_×10--
武中·m
Allowance difference
The amount of aluminum oxide on the standard curve becomes u%: the mass of the sample, 8.
The value of the laboratory test result should be less than the value shown in the table below. Lead
0. 10 ~ 0. 5n
> 0. 50 ~-1. 00
Additional Notes:
This standard is under the jurisdiction of the Chemical Industry Design and Research Institute of the Ministry of Chemical Industry. The Ministry of Chemical Industry Chemical Industry Design and Research Institute is responsible for drafting this standard. The main drafter of this standard is Di Lihua.
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