Coal asphalt is an important raw material in the field of petroleum processing and coal chemical industry, and its quality directly affects road construction and other industrial applications. Taric acid and phenol are key chemical components in coal pitch, and understanding their content is essential to evaluate the performance of asphalt. In this paper, we will introduce in detail the detection methods of taric acid and phenol content of coal pitch, including experimental equipment, steps and calculation methods.
This method aims to determine the taric acid content of road coal asphalt, which is widely applicable to the quality control and research of asphalt products.
Double-ball measuring tubes – made of glass
Iron frame - attached to the iron ring, the inner diameter of the ring is 49-56mm.
Coal pitch distillation test device
Sodium hydroxide solution – 18.3% concentration.
Solvents – trichloroethylene, benzene.
Distilled water, thermostatic sink, Erlenmeyer flask and other auxiliary equipment.
Preparation
First, wash the tubing tube with trichloroethylene, lotion and distilled water to ensure that the equipment is clean. Next, the coal pitch specimen is treated according to the T0641 distillation method, the fractions are distilled from different temperature ranges, and their total mass is recorded.
Test procedure
Place the distilled fraction in an Erlenmeyer flask and heat it in a 60 °C constant temperature bath for 20 minutes until the fraction is completely melted.
The fraction is injected into a double-ball assay tube, rinsed with a benzene Erlenmeyer flask, and the wash is also transferred to the assay tube.
Add 50mL of sodium hydroxide solution, shake for 3 minutes, and let stand until the solution is stratified.
Drain the lower liquid from the double ball tube, then add 30 mL of sodium hydroxide solution and repeat the above steps.
Finally, 65 mL of benzene was added to the assay tube, shaken and washed several times, and then allowed to stand, and the scale on the tube was accurately read, and the volume of taric acid was recorded.
The volume of taric acid is calculated according to the formula described below, and the taric acid content of the sample is expressed as a percentage by volume.
At least two parallel tests of the same sample, if the error of the two measurement results does not exceed 1%, the average value will be taken as the test results.
This method is used to determine the phenolic content of road coal asphalt, which is suitable for the quality control of various coal asphalt.
Double-ball test tube – same as taric acid content test.
Iron frame - iron ring with an inner diameter of 49-56mm.
Sodium hydroxide solution – chemically pure, concentration of 10% and sodium chloride added to saturation.
Lotion - a mixture of potassium dichromate and concentrated sulfuric acid.
Benzene, distilled water, etc.
Preparation
Similarly, wash the double-ball assay tubes using a wash solution and sodium hydroxide solution to ensure experimental accuracy.
Test procedure
Sodium hydroxide solution treatment – Inject the sodium hydroxide solution into the B ball of the assay tube and read the scale value.
Add the medium oil fraction – pour the distilled medium oil fraction into the assay tube and rinse with benzene.
Shake to mix – invert the assay tube so that the sodium hydroxide solution is well mixed with the medium oil fraction and let it stand for 1 hour to observe the stratification.
The phenolic content of coal pitch is also expressed as a percentage by volume, which is calculated in a similar way to the taric acid content.
Make sure to run at least two parallel tests on the same specimen to get an accurate average as the final result.
The taric acid and phenol content detection methods of coal pitch provide a scientific basis for ensuring the performance and safety of asphalt products. Through the above-mentioned standardized experimental procedures, the quality of coal asphalt can be accurately evaluated, and the sustainable development of road construction and related industries can be promoted.