Test method for mixed catalyst solution of cobalt acetate, manganese acetate and hydrobromic acid (5)

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Dilute the sample with water, filter, separate the water-insoluble matter, dry and weigh it until the mass is constant, and calculate the mass fraction of the water-insoluble matter.

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Figure 1 Schematic diagram of suction filter device

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Put the filter membrane in an oven at (110±2)°C for 30 minutes, take it out and place it in a desiccator for 30 minutes, weigh it, repeat the above operation until the quality is constant, and record the quality of the filter membrane

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The mass fraction of water insoluble matter w ₄ , the value is expressed in %, calculated according to formula (5):

w ₄ =(m ₁ -m ₂ )/m×100.

Where:

m ₁ ——the value of the mass of water-insoluble matter added to the filter membrane, in grams (g);

m ₂ -the value of the filter membrane mass, in grams (g);

m-The value of the mass of the sample, in grams (g)

The calculation result is expressed to two decimal places

Take the arithmetic mean of the two parallel determination results as the determination result

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In a nitric acid medium, after heating the sample to remove the interference of hydrobromic acid , chloride and silver ions form insoluble silver chloride precipitates, making the sample solution turbid, and the sample solution is compared with the standard turbidity solution of the vapor (Cl).
, To determine the limit value of chloride content
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The detection range is chloride (CI) ₂ mg/L～50mg/L
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2 Reagents

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1 Nitric acid solution: 3+7
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2 Silver nitrate solution: 17g/L
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3 Chloride (CI) standard solution: 0.
1mg/mL
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3 Analysis steps

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1 Preparation of standard turbidity solution

Weigh 10g or an appropriate amount of sample, accurate to 0.
1g, place it in a 50mL beaker, add 20mL nitric acid solution, heat to boiling for about 5min (note: this operation should be carried out in a fume hood), cool to room temperature, add 5mL silver nitrate solution , Mixing: filter the solution into a 50mL colorimetric tube, add 2mL nitric acid solution, 5mL silver nitrate solution, accurately add appropriate amount of chloride (CI) standard solution, dilute to 50mL, and mix
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The amount of chloride (CI) standard solution added should be determined according to the limit value of the amide content of the sample.
The principle of the amount added is that the turbidity of the standard turbidity solution is close to or deeper than the turbidity of the sample solution
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2 Determination of sample solution

Weigh 10g or an appropriate amount of sample, accurate to 0.
1g, place it in a 50mL beaker, add 20mL of nitric acid solution, heat to boiling for about 5 minutes, rinse the beaker with a small amount of water, continue heating for 10 minutes, cool to room temperature, and transfer to a 50mL colorimetric tube , Add 2mL slightly acidic solution, 5mL silver nitrate solution, dilute to 50mL, and mix
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After placing it together with the standard turbidity solution for 10 minutes, perform the axial daily turbidity
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Related links: Test method for mixed catalyst solutions of cobalt acetate, manganese acetate, and hydrobromic acid (4)