Measurement method for industrial grade sulfuric acid:

This method is only applicable for estimating the concentration of sulfuric acid, and is only suitable for estimating industrial sulfuric acid with a concentration of less than 98% (m/m). Estimated values cannot be used as analytical measurement results. [2]

B. 1 Method principle

Measure the density of sulfuric acid at 20 ℃ using a densimeter or convert it to the density at 20 ℃ by measuring the density at working temperature. Look up the table and use interpolation to find the sulfuric acid concentration corresponding to the density.

B. 2 Instruments

Density meter (calibrated at 20 ℃ with a scale of 0.005g/cm3);

Glass measuring cylinder (with a minimum volume of 500ml, a diameter greater than the density meter, a diameter of at least 25mm, and a height greater than the immersion height of the density meter, at least 25mm);

Thermometer (0-50 ℃, with a division value of 0.1 ℃).

B. 3 Measurement steps

Follow the procedures of B3.1 or B3.2.

B3.1 Take approximately 500ml of the sample and place it in a glass measuring cylinder. Adjust the temperature of the sample in the cylinder to 20 ± 0.5 ℃.

Insert a densitometer and check again if the sample temperature is 20 ± 0.5 ℃ after stabilization. Read the density indicated by the densitometer scale.

B3.2 Take approximately 500ml of the sample and place it in a glass measuring cylinder. Measure the temperature of the sample using a thermometer.

Insert a densitometer and measure the sample temperature again after stabilization, and read the density indicated by the densitometer scale.

B3.3 Estimation of sulfuric acid concentration

When measuring the density according to B3.1, according to the density indicated by the densitometer, the corresponding concentration can be found by comparing the density and concentration of sulfuric acid at 20 ℃ in Table B2.

When measuring density according to B3.2, convert the density indicated by the density meter to the density at 20 ℃ according to equation (B1).

ρ 20= ρ T * [1+0.000025 (20-t)] - (20-t) * K (B1)

In the equation ρ Density at 20-20 ℃, g/cm3;

ρ T - density indicated by the densitometer during measurement, g/cm3;

0.000025- Density meter glass expansion coefficient;

T - sample temperature during measurement, ℃;

K - Temperature correction coefficient for sample density, given in Table B1.

Table B1 Temperature Correction Factors for Density

Density, g/cm3 correction factor K Density, g/cm3 correction factor K

1.151-1.200 0.0007 1.561-1.700 0.0010

1.221-1.420 0.0008 1.701-1.770 0.0011

1.421-1.560 0.0009 1.771-1.840 0.0012

Industrial grade sulfuric acid