HG 2957.5-1984 Determination of aluminum content of alum ore Volumetric method
Some standard content:
1 Scope of application
National Standard of the People's Republic of China
Determination of aluminum content of alunite ore
Volumetric method
Alunite ores-Betermination of aluminiwm content.-Volumetric method
UDC 549.762 : 543
-24:546.621
GB 4581.5-84
Adjusted to: MG/2Ps7.5 -1Pa4
This standard specifies the use of fluoride salt to replace the FDTA volumetric method to determine the oxidation content of more than 5% in alunite ore. 2 Related standards
GB4581.1--84 "General rules for analysis of alunite ore". Gi34581.2-84 "Methods for taking and preparing analysis samples of alunite ore". 3 Method Summary
The sample is alkali fused to separate and remove disturbing elements such as iron and titanium by precipitation. Add excess EDTA to complex with aluminum ions. At pH-6, use zinc acetate to titrate excess FDTA, then add sodium fluoride to convert aluminum ions complexed by EDTA into fluoroaluminum complex ions and release an equivalent amount of EDTA. Then use zinc acetate solution to titrate the released EUTA to calculate the content of aluminum oxide. 4 Reagents and solutions
4.1 Sodium hydroxide (GB629-81).
4.2 Sodium percyanide.
(Specific gravity 1.19): 1+1.
4.3 Hot acid (GB 622-77)0
4.4 Nitric acid (GB626-78)
(Specific gravity 1.42).
4.5 Glacial acetic acid (GB676-78) (specific gravity 1.05). 4.6 Ammonia water (GB631-77) (specific gravity 0.90): 1+1. Sodium fluoride (GB1264-77): 4%, stored in a material bottle. 4.7
4.8 p-nitrophenol: 0.2% ethanol solution. Xylenol: 0.5% ethanol solution. Weigh 0.5g xylenol orange and dissolve it in 20ml water, add 80ml ethanol, spread evenly. 4.9
Store in a brown bottle.
Absolute ethanol (GB678-78).
Ammonium acetate (GB1292-77).
4.12 Acetic acid-ammonium acetate buffer solution (pH ~ 6): weigh 300 g ammonium acetate, dissolve in 500 ml water, filter, add 12.3 ml glacial acetic acid (4.5), dilute to 1000 ml with water, shake well. 4.13 Aluminum flakes.
4.14 Standard aluminum solution: 1.000 mg aluminum oxide per liter. Accurately weigh 0.5293 g aluminum flakes (4.13) (the oxide film needs to be removed) in a 150 ml beaker, add 20 ml aqua regia, heat on a hot plate to dissolve, cool and transfer to a 1000 ml volumetric flask, dilute to scale with water, shake well. 4.15 Disodium ethylenediaminetetraacetate (GB 140178) (EDTA): about 0.02M. 4.16 Zinc acetate (HG 3-1098-77): about 0.02M. 4.16.1 Preparation
Promulgated by the State Bureau of Standards on July 20, 1984
Implemented on June 1, 1985
GB 4581.5—84Www.bzxZ.net
Weigh 4.4 g of acetic acid 2n(CH,COO)·2H0 and dissolve it in water. Add 2 ml of glacial acetic acid (4.5), dilute to 1000 ml with water, and shake for approx.
4.16.2 Calibration
Put 20 liters of aluminum standard solution into a 500 mm Erlenmeyer flask, add 30 ml of 0.02M EDTA solution, and perform the following operations as in 5.2. 4.16.3 Calculation of titer
The titer of acetic acid solution on aluminum oxide is calculated according to formula (1): T
Wherein: - the titer of zinc sulfate solution on aluminum oxide, g/ml; the weight of aluminum oxide contained in the absorbed potassium standard solution, g; the volume of zinc sulfate solution, liters.
5 Determination Procedure
5.1 Weigh 0.2g of sample and spread it evenly in a silver crucible or nickel-gold glass. Add a small amount of anhydrous ethanol to wet the sample. Cover the surface with 4g of sodium hydroxide (4.1) and 0.2g of sodium peroxide (4.2). Cover the sample in a furnace and heat it from low temperature to 650-700℃ to melt for 15-20 minutes (take it out and shake it once at 650℃), take it out and cool it. Put the sample into a 150ml beaker, add 50ml of hot water, cover the surface with blood, heat to remove the molten block, wash it out with hot water, [if the solution is green, add 5-6 drops of ethanol (4.10)] and boil it for a while. After cooling, transfer to a 10-liter volumetric flask, dilute to the mark with water, shake well, and filter immediately. 5.2 Pipette 50 ml of the filtrate into a 500 ml flask, add 30-10 ml of EDTA solution (4.15), and then dilute to about 150 liters with water, add 2-3 drops of hydroxyphenol indicator solution (4.8), quickly neutralize with hydrochloric acid solution (4.3) until the yellow color disappears, add 10 liters of acid-ammonium acetate buffer solution (4.12) of pH 6, heat and boil for 2-3 minutes. Remove and cool to room temperature. Add 3-4 drops of dioxin orange indicator solution (4.9), and titrate with zinc acetate solution (4.16) until the solution changes from yellow to red (ignore the reading). Add 20 ml of sodium fluoride solution (4.7), shake, heat and boil for 2-3 minutes, remove and cool to room temperature. Add 1-2 drops of xylenol orange indicator solution (4.9) and titrate with zinc acetate solution (4.16) until the solution changes from yellow to red. 6. Expression and calculation of results
The percentage content (X) of cobalt oxide (AI2O3) is calculated by formula (2): V
Where: V
-total volume of the test solution, ml;
volume of the aliquot solution, ml:
(2))
-residue of zinc acetate solution, goodness,
titer of zinc acetate solution against lead oxide, g/L: W
tolerance
weight of sample, g.
Content of alumina, %
Tolerance (absolute value), %
GB 4581.5--84
Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and drafted by the Chemical Industry and Mining Design Institute of the Ministry of Chemical Industry. The main drafter of this standard is Cheng Maomei.
From the date of implementation of this standard, the original Ministry of Chemical Industry standard HG1-353-66 "Alumite System-Analysis Method" will be invalid. 11
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