The fly ash testing items mainly include two aspects: physical properties and chemical composition. These tests and their methods are described in detail below:
1. Physical performance testing.
Density detection. Density is one of the important parameters of fly ash quality, and its detection method usually adopts the pycnometer method. The steps are as follows:
1) Clean the pycnometer and dry it
2) Fill the pycnometer with a fly ash sample, weigh and record;
3) Add an appropriate amount of distilled water to the pycnometer, weigh and record;
4) Mix the water and sample in the pycnometer and stir well, and then let stand for a while
5) Pour out the liquid in the pycnometer, weigh and record again after drying the pycnometer.
By calculating the formula, the density of fly ash can be derived.
Moisture content detection.
Moisture content refers to the percentage of the amount of moisture contained in the fly ash to the mass of the dry fly ash. The detection method is as follows:
1) Take a certain amount of fly ash sample and record its quality;
2) Place the sample in an oven and dry at 105 °C to constant weight
3) Take out the sample, cool it to room temperature and weigh it again and record it.
By calculating the formula, the moisture content of fly ash can be obtained.
Fineness detection. Fineness refers to the fineness of fly ash particles, and its detection method usually adopts the sieving method. The steps are as follows:
1) Put a certain amount of fly ash sample into a sieve;
2) Use a vibrating sieve or manual sieving method to pass the sample through a sieve with different pore sizes
3) Collect samples on each sieve, weigh them separately and record them;
4) Calculate the mass percentage of the sample on each sieve.
By analyzing the distribution of samples on different sieves, the fineness of fly ash can be determined.
2. Chemical composition testing.
Silica content testing.
Silica is one of the most abundant elements in fly ash, and its detection method can be acid or alkali soluble. The steps are as follows:
1) Put the fly ash sample into an acid-soluble or alkali-soluble container;
2) Add an appropriate amount of acid or alkali solution to fully dissolve the sample;
3) Filter the dissolved solution and collect the filtrate;
4) Titration or colorimetric method was used to determine the content of silicon in the filtrate.
By calculating the formula, the amount of silicon in fly ash can be obtained.
Aluminum content testing.
Aluminum is also one of the more abundant elements in fly ash, and its detection method is similar to that of silicon content detection. The steps are as follows:
1) Put the fly ash sample into an acid-soluble or alkali-soluble container;
2) Add an appropriate amount of acid or alkali solution to fully dissolve the sample;
3) Filter the dissolved solution and collect the filtrate;
4) Determination of aluminum content in the filtrate by titration or colorimetric method.
By calculating the formula, the amount of aluminum in fly ash can be determined.
Iron content test.
The content of iron in fly ash is relatively low, but its presence is more complex. Iron content can be determined using the same acid-soluble or alkali-soluble method. The procedure is similar to that for silicon and aluminum. By calculating the formula, the amount of iron in fly ash can be obtained.
Calcium content test.
The content of calcium in fly ash is low, but its existence form is more special. The determination of calcium content can be performed using the following methods:
1) Put the fly ash sample into an acid-soluble container;
2) Add an appropriate amount of acid solution to fully dissolve the sample;
3) Filter the dissolved solution and collect the filtrate;
4) Titration was used to determine the calcium content in the filtrate. By calculating the formula, the amount of calcium in fly ash can be obtained.
Sulfur content detection.
Sulfur is found in lower levels in fly ash but is also one of the elements of concern. The determination of sulfur content can be carried out using the following methods:
1) Put the fly ash sample into a high-temperature furnace and burn it;
2) Dissolve the burned sample with acid;
3) Filter the dissolved solution and collect the filtrate;
4) Titration was used to determine the sulfur content in the filtrate. By calculating the formula, the amount of sulfur in fly ash can be obtained.