GB/T 2999-2025Refractory materials - Determination of bulk density of granular materials (English PDF)

6.1 Specimen Preparation

Take representative specimens from the laboratory sample as specified. After crushing, sieve (particles smaller than 5.0 mm may be directly sieved), until all specimens pass through a test sieve with a 5.0 mm aperture (8.1.1). In addition, discard particles smaller than 2.0 mm. Place the specimens on the test sieve (8.1.1) and use water to wash them or blow air (for water- sensitive specimens) to remove dust or loose particles adhering to the surface.

6.2 Number of Specimens

Use the quartering method to reduce the dried granular specimens to 200 g ~ 500 g for testing.

8.1 Equipment

8.1.1 Test sieve. conforming to the provisions of GB/T 6005, with apertures of 2.0 mm and 5.0 mm, and equipped with a sieve bottom and sieve cover.

8.1.2 Electric drying oven. temperature control accuracy of 110 °C ± 5 °C.

8.1.3 Desiccator.

8.1.4 Balance. with a division value of 0.01 g.

8.1.5 Non-absorbent fiber cloth, such as polyester and nylon fiber cloth.

8.1.6 Immersion tank.

8.1.7 Vacuumizing device. capable of reducing the absolute pressure to no more than 2,500 Pa and measuring the absolute pressure.

8.1.8 Immersion liquid. for materials that do not react with water, the immersion liquid shall be pure water. For materials that are susceptible to hydration reaction in contact with water, kerosene or other suitable organic liquids shall be used. The immersion liquid shall be stable at an absolute pressure higher than that used in the test. If the immersion liquid becomes contaminated or flocculent, it shall be promptly replaced.

8.1.9 Basket with netting on top. a basket with a handle, made with a mesh with an aperture of

1 mm.

8.1.10 Container with overflow tube. with an appropriate size to accommodate the specimen

when determining the mass of a saturated specimen suspended in the immersion liquid.

8.1.11 Cotton gauze. approximately 60 cm x 60 cm in size.

8.1.12 Weighing bottle. 60 mm in diameter, 30 mm in height.

8.1.13 Hydrostatic balance or hydrometer. with a division value of 0.001 g/cm3.

8.2 Specimen Immersion

Carefully place the weighed specimen (m1) on a non-absorbent fiber cloth (8.1.5), use a string to securely wrap it, and place it in an immersion tank (8.1.6). Place the tank in a vacuumizing device (8.1.7) and evacuate it to an absolute pressure of less than 2,500 Pa. Maintain the specimen at this vacuum level for 5 minutes. Then, disconnect the immersion tank from the vacuum pump. If the specimen in the immersion tank no longer degasses and the pressure no longer increases, re-connect the immersion tank to the vacuum pump and start injecting the immersion liquid. Within 3 minutes, fill the tank, until the immersion liquid covers the specimen by approximately 20 mm. Maintain this pressure for approximately 5 minutes, then, turn off the vacuum pump, remove the immersion tank, and allow it to rest in air for 30 minutes. Throughout the immersion process, the specimen shall remain covered by the immersion liquid, until it is removed and weighed.

8.3 Determination of the Mass (m2) of Saturated Specimens Suspended in the

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