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Testing Method of Chemical Stability of Daily-use Enamel Cookware

Testing Method of Chemical Stability of Daily-use Enamel Cookware

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  • Time of issue:2023-04-19
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(Summary description)Methods for testing the acid resistance, antimony reaction, lead reaction and alkali resistance of daily-use enamel cookware:

Testing Method of Chemical Stability of Daily-use Enamel Cookware

(Summary description)Methods for testing the acid resistance, antimony reaction, lead reaction and alkali resistance of daily-use enamel cookware:

  • Categories:Company news
  • Author:
  • Origin:
  • Time of issue:2023-04-19
  • Views:0
Information

Methods for testing the acid resistance, antimony reaction, lead reaction and alkali resistance of daily-use enamel cookware:

1. Determination of acid resistance

1. Weightlessness method

To clean the sample, use 1.5ml of 4% acetic acid per square centimeter of immersion area, use a measuring cylinder to take the proportion of 4% acetic acid, use the measuring cylinder to measure 4% (weight percent) acetic acid solution into the cup to be tested, record Lower the liquid level, heat on a 600-watt electric stove, and boil slightly for 1 hour. During the boiling process, the evaporated acid liquid is replenished at any time to keep the liquid level at the same height. After cooling, use the original acid solution to adjust to the original liquid level, so that the liquid level is always kept at the same height. After cooling, adjust to the original liquid level with the original acid solution, stir evenly with a glass rod, draw 100ml with a pipette and pour it into a beaker with constant weight. Evaporate to dryness on the heating electrode, then dry in an oven at 100~105°C, and weigh until constant weight.

Weight loss calculation method: W=0.015(A2-A1)X1000

In the formula, W——weight of sediment per unit area, mg/cm²

A2 - the weight of the container and the sediment, in grams;

A1——the weight of the container, in grams.

Calculation of the amount of acid used in the barrel-shaped sample:

V=ΠR²H

V=1.5F=1.5(ΠR²=2ΠRH)

That is, 1.5 (ΠR²+2ΠRH)=ΠR²H

So H=1.5R/R-3

In the formula, V - the number of milliliters of acetic acid solution contained in the sample;

R - the radius of the barrel-shaped sample;

H - the height of acetic acid;

F - the area of the sample subjected to the action of the acid solution.

2. Trace method

Suitable for miscellaneous products.

Immerse the filter paper strip in 0.2% (weight percent) acetic acid solution, take out the filter paper strip and stick it close to the inside of the sample to be tested, and place it in the greenhouse for 20 minutes. Remove the filter paper strip, wash and dry the sample with water, smear it with manganese dioxide over 200 mesh, and then wipe it with absorbent cotton. There must be no traces of pollution on the surface of the corroded area.

2. Antimony reaction

Take out 5ml of the acid solution used for the determination of acid resistance, put it in an evaporating dish and concentrate it to 1~2ml, add a few grains of sodium thiosulfate, if there is antimony, there will be orange-red precipitation.

3. Lead reaction

Take out the acid solution used for acid determination, concentrate to 1/2 of the original volume, and add a few drops of 10% potassium chromate solution. If lead is present, there will be a yellow precipitate.

4. Determination of Alkali Resistance

Place the sample at an angle, inject it with boiling 20% sodium carbonate solution, leave it at room temperature for 2 hours, pour off the lye, wash it with water, dry it, and check whether the enamel loses its original luster.

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