Customs knowledge: How much do you know about imported cemen

作者：迦泰通报关 电话：18521306667 来源:www.jtia56.cn 发布日期：2023-10-10 15:50:05

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How much do you know about imported cement

Cement is the most commonly used and widely used building material in construction engineering, and its quality is directly related to the quality and safety of buildings. In recent years, the import volume of cement in China has been increasing year by year. In 2020, the value of imported cement and cement clinker was 10.479 billion yuan, a year-on-year increase of 31.34%.

HS code classification of imported cement

1. Portland cement. Clinker is finely ground and made into cement, which is currently the most common variety with silicate as the main component. According to tax classification, white cement is classified as 2523.2100, while other types of Portland cement are classified as 2523.2900.

2. Alumina cement. Also known as high alumina cement or refractory cement, with aluminate as the main component and alumina content of about 50%. It has high early strength, corrosion resistance, and high temperature resistance. According to tax classification, bauxite cement is classified as 2523.3000.

3. Common cement also includes slag cement, sulfate rich cement (made by mixing finely ground blast furnace slag with accelerator and gypsum), and volcanic ash cement, which are classified according to tax regulations and classified as 2523.9000.

4. The semi-finished products obtained by sintering limestone containing natural or artificially mixed with appropriate proportions of clay as cement clinker should be classified as 2523.1000 according to tax regulations.

Quality and safety requirements for imported cement

China's "General Portland Cement" (GB 175-2010) sets clear requirements for cement quality:

1. Requirements for cement identification labels

The cement packaging bag should be clearly marked with: executive standard, cement variety, code, strength grade, manufacturer's name and number, factory number, packaging date, and net content.

Both sides of the packaging bags for Portland cement and ordinary Portland cement should be printed or sprayed with red cement names and strength grades.

The packaging bags of slag Portland cement, fly ash Portland cement, volcanic ash Portland cement, and composite Portland cement should be printed or sprayed with black or blue cement names and strength grades on both sides. When shipping in bulk, a card with the same content as the bag label should be submitted.

2. Radioactivity

The specific activity of radioactivity should meet both the internal exposure index IRa not greater than 1.0 and the external exposure index Ir not greater than 1.0.

3. Chemical composition

4. Water soluble chromium (VI) in cement

The water-soluble chromium (VI) in cement should comply with the requirements of GB31893, with a limit value of ≤ 10mg/kg.

5. Stability

1) The boiling method inspection is qualified.

2) The stability of the autoclave is qualified.

6. Strength

7. Fineness

The fineness of Portland cement is expressed in terms of specific surface area, which is not less than 300m2/kg but not more than 400m2/kg.

The fineness of ordinary Portland cement, slag Portland cement, fly ash Portland cement, volcanic ash Portland cement, and composite Portland cement is 45% μ The residue on the m square hole sieve is not less than 5%.

When there are special requirements, they shall be determined through negotiation between the buyer and the seller.

8. Setting time

The initial setting time of Portland cement shall not be less than 45 minutes, and the final setting time shall not exceed 390 minutes.

The initial setting time of ordinary Portland cement, slag Portland cement, fly ash Portland cement, volcanic ash Portland cement, and composite Portland cement shall not be less than 45 minutes, and the final setting time shall not exceed 600 minutes.

9. Composition requirements